Research ArticleChemical and Oxygen Isotopic Composition of Roman andLate Antique Glass from Northern Greece

Alberta Silvestri1 Elissavet Dotsika23 Antonio Longinelli4

Enricomaria Selmo4 and Sophia Doukata-Demertzi5

1Department of Geosciences University of Padova Via G Gradenigo 6 35131 Padova Italy2Institute of Material Science Stable Isotope Unit NCSR ldquoDemokritosrdquo Aghia Paraskevi 15310 Attiki Greece3Institute of Geosciences and Earth Resources CNR Via G Moruzzi 1 56124 Pisa Italy4Department of Physics and Earth Sciences University of Parma Via GP Usberti 157A 43100 Parma Italy512th Ephorate of Byzantine Antiquities General Directorate of Antiquities and Cultural Heritage Athens Greece

Correspondence should be addressed to Elissavet Dotsika edotsikainndemokritosgr

Received 15 November 2016 Accepted 8 March 2017 Published 18 April 2017

Academic Editor Kaustubha Mohanty

Copyright copy 2017 Alberta Silvestri et alThis is an open access article distributed under theCreative CommonsAttribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

The present paper emphasizes the importance of measuring the oxygen isotopic and chemical compositions of ancient glass inorder to constrain some features such as age raw materials and production technologies and to identify the ldquofingerprintrdquo of localproductions In this context thirty-nine Roman and late Antique glass samples and eight chert samples from northern Greece wereselected and analysed for their oxygen isotopic and chemical compositions Results show that the majority of glass samples areproduced using natron as flux and have 12057518O values of about 155permil plus or minus a few tenths of one per mil suggesting that rawmaterials probably come from Levantine area Four samples are heavily enriched in 18O and their chemical composition clearlyshows that they were made with soda plant ash as flux Isotopic and chemical data of Greek chert samples support the hypothesisof local production of the above samples About half of the glass samples have chemical compositions which allow their age to beconstrained to the late Antique period For the remaining glass similarities with literature compositional groups are reported anddiscussed

1 Introduction

It is well-known that at different periods of history glasswas produced by adding a flux composed of natron (termhere adopted with the meaning of usually complex oftenpolyphase evaporitic deposits rich in carbonates of sodium)or soda ash from the combustion of halophytic plants such asSalsola or Salicornia or potash ash from the combustionof trees such as beech birch and oak to quartz pebblesor quartz-limestone sand [1] The use of these different rawmaterials influences not only final chemical compositions ofthe resulting glass [1] but also the oxygen isotopic composi-tionsThe addition of natron during melting normally causes18O enrichment in final glass at least when natron from theevaporitic lakes ofWadiNatrun in Egypt is used as its oxygenisotopic composition is heavily enriched in 18O [2 3] The

ash should not greatly affect oxygen isotopic composition ofglass which reflects that of the network former (normallySiO2 added to the batch in the form of quartz pebbles orquartz-limestone sand) [3] although Tite et al [4] statedthat ash when relatively rich in carbonates bicarbonates andhydrates may cause some isotopic changes in final product

In this context the existence inGreece of locally producedglass vessels [5] as well as the import and trade of raw glassand glass artefacts probably produced inNear East orMiddleEast countries draws attention to the importance of identify-ing the ldquofingerprintrdquo of Roman and late Antique glass madein Greece of distinguishing raw materials and fluxes usedfor glass melting of defining production technologies andindirectly of better constraining the age of analysed objectsMeasurements of oxygen isotopic and chemical composi-tions of glass samples and possible raw materials seem

HindawiJournal of ChemistryVolume 2017 Article ID 2956075 14 pageshttpsdoiorg10115520172956075

2 Journal of Chemistry

promising tools to advance in this direction To the best ofour knowledge the present paper is the first contributionreporting chemical and oxygen isotopic analyses of Romanand late Antique glass from northern Greece and chemicalmineralogical and oxygen isotopic analyses of Greek chertwhich revealed particularly interesting to discriminate var-ious raw materials and production technologies and toadvance hypothesis on possible local products

2 Materials and Methods

21 Materials In the present study thirty-nine glass sampleswere analysed from the isotopic and chemical points ofview Twenty-nine samples come from various archaeologicalexcavations in Thessaloniki In particular ten samples comefrom the Agora area The age of these samples is generallycomprised within the Roman and late Antique periods(1stndash6th centuries AD)Their colour varies from colourless tolight green light blue greenbrown green-blue and blue(Table 1) The other nineteen samples come from variousarchaeological excavations in Thessaloniki and their age iscomparable with that of the samples fromAgoraTheir colouris mainly green or greenish but blue light yellow brownaquamarine light green or colourless samples are alsoselected (Table 1)

The fragmentary state of the Thessaloniki glass samplesdid not allow typological characterisation except for thosenamed 1-3 2-3 3-3 and 6-3 which were all identified asbottles and sample 3-4 which is an oil lamp

In addition to glass from Thessaloniki a set of tensamples all typologically identified as pane fragments comesfrom the palaeo-Christian church of Maroneia located in thenorth-easternmost part of Greece The age of the Maroneiasamples ranges from the 4th to the 6th centuries AD and thecolours range from colourless to light yellow light greengreen green-blue and light blue (Table 1)

Finally eight samples composed of chert from the quarryin Triadi of Thessaloniki (Central Macedonia Greece) wereselected for isotopic chemical and mineralogical analysesChert is a hard dense cryptocrystalline sedimentary rockessentially composed of tiny quartz crystals that is less thanabout 30120583m in diameter and may occur as nodular con-cretions and less commonly as layered formations (beddedchert) Chert is found in both western Greece and theThessa-loniki region (northern Greece) as layers in carbonate andormagmatic rocks and chert quarries dated to prehistorictimes have been found near Thessaloniki In particular theabove prehistoric chert quarries are located along a steepvalley 2 km north of the Triadi village at the foothills of theChortiatisMountain (CentralMacedonia)The rocks are partof aMesozoic ophiolite complex and consistmainly of dunitesand peridotites partly serpentinized as well as gabbrosExtended silicified rocks comprising mostly chert occur atthe upper part of the dunites and peridotites and below thegabbros In addition rare milky-white microcrystallinequartz veins crosscut silicified rocks The existence of chertformations in Greece would be in favour of their use for glassproduction and the present paper is also aimed at verifyingthis hypothesis

22 Methods Oxygen isotope measurements on glass andchert samples were carried out according to well-establishedtechniques In order to avoid contamination glass sampleswere carefully cleaned prior to analysis Fragments werecrushed in a stainless steel mortar and then finely groundin an agate mortar Aliquots of about 6-7mg of the resultingpowder were placed in the nickel vessels of a fluorination lineThe samples were then degassed to better than 10minus3mmHgfor at least one hour and frozen to the temperature ofliquid nitrogen a fivefold stoichiometric amount of BrF5 wasintroduced into each vessel and the samples were reactedat 600 plusmn 10∘C for about 12 h The oxygen produced by thereaction was converted to CO2 by cycling over a hollowcylinder of spectrographically pure graphite and inductivelyheated to about 800∘C in the presence of a platinum catalystCO2 samples were measured for their oxygen isotope ratiosin a Finnigan Delta S mass spectrometer versus a laboratoryCO2 standard This standard was prepared by reacting apowdered very pure Carrara marble with 100 phosphoricacid at 25∘C Its isotopic values are the following +245permil(12057513C versus VPDB) and minus245permil (12057518O versus VPDB) Untilnow we have calibrated our working standard versus NBS-19the isotopic values of which were taken as +195permil (12057513C)and minus220permil (12057518O) and versus NBS-20 with isotopic valuesof minus106permil (12057513C) and minus414permil (12057518O) (the NBS-20 isotopicstandard has not been available for many years We had rea-sonable quantities of NBS-19 andNBS-20 standards inheritedfrom three Italian universities and three foreign researchcentres where A Longinelli previously worked)

Isotopic results are reported in the usual delta termi-nology versus the VSMOW isotopic standard delta beingdefined as follows

120575 = [(119877sample minus 119877standard)119877standard ] times 1000 (1)

where 119877 is the ratio between the heavy and the light isotopein this case 18O16O The delta values were converted fromVPDB to VSMOW standard according to the method ofFriedman and OrsquoNeil [6]

The reported values are the means of two or more con-sistent measurements of each sampleThe standard deviationof the glass measurements is very good ranging on averagebetween plusmn01 and plusmn02permil (2120590)

The chemical compositions of glass samples weredetected by electron microprobe analysis (EMPA) Theinstrument used for quantitative analysis of major andminor elements was a CAMECA SX50 equipped with fourwavelength-dispersive spectrometers (WDS) The bulk com-position of the analysed materials was identified by randompoint microanalyses (generally 10 per sample) and meansand standard deviations were calculated Standard deviationsrange from about 002 to about 05 thus proving thehomogeneity of the glass fragments only mean values arereported in the tables Analysed elements were NaMg Al SiP S Cl K Ca Ti Mn Fe Sb Co Ni Cu Zn Sn and PbThefollowing standards were employed synthetic pure oxidesfor Mg Al Fe and Sn a synthetic MnTi oxide for Mn and Ti

Journal of Chemistry 3

Table 1 List of analysed glasses from Greece Colour age and provenance also shown

Sample Colour Age ProvenanceNumber Century AD1-1 Light green 1stndash6th Agora-Thessaloniki2-1 Green blue 1stndash6th Agora-Thessaloniki3-1 Colourless 1stndash6th Agora-Thessaloniki4-1 Blue 1stndash6th Agora-Thessaloniki5-1 Light green 1stndash6th Agora-Thessaloniki6-1 Colourless 1stndash6th Agora-Thessaloniki7-1 Greenbrown 1stndash6th Agora-Thessaloniki8-1 Light green 1stndash6th Agora-Thessaloniki9-1 Light blue 1stndash6th Agora-Thessaloniki10-1 Colourless 1stndash6th Agora-Thessaloniki1-2 Light green 4thndash6th Maroneia church2-2 Green 4thndash6th Maroneia church3-2 Light yellow 4thndash6th Maroneia church4-2 Green-blue 4thndash6th Maroneia church5-2 Light green 4thndash6th Maroneia church6-2 Colourless 4thndash6th Maroneia church7-2 Light yellow 4thndash6th Maroneia church8-2 Very light brown 4thndash6th Maroneia church9-2 Light blue 4thndash6th Maroneia church10-2 Very light green 4thndash6th Maroneia church1-3 Light green 1thndash6th Agora cryptoporticus-Thessaloniki2-3 Colourless 1thndash6th Agora cryptoporticus-Thessaloniki3-3 Light green 3th-4th West cemetery tomb-Thessaloniki4-3 Green 1thndash6th School of religion-Thessaloniki5-3 Greenish 1thndash6th School of religion-Thessaloniki6-3 Colourless 6th Administration building-Thessaloniki7-3 Light yellow 1thndash6th Administration building-Thessaloniki3-4 Light green 5th-6th landscape of Nastos-Thessaloniki4-4 Greenish 1stndash6th Socratous street-Thessaloniki5-4 Greenish 1stndash6th Socratous street-Thessaloniki6-4 Greenish 1stndash6th Socratous street-Thessaloniki7-4 Aquamarine 1stndash6th Socratous street-Thessaloniki8-4 Green 1stndash6th Thessaloniki9-4 Colourless 1stndash6th Thessaloniki10-4 Blue 1stndash6th Thessaloniki11-4 Green 1stndash6th Thessaloniki12-4 Brown 1stndash6th Thessaloniki13-4 Greenish 1stndash6th Thessaloniki14-4 Green 1stndash6th Thessaloniki

albite for Na diopside for Si and Ca apatite for P sphaleritefor Zn and S vanadinite for Cl orthoclase for K Sb2S for SbPbS for Pb and pure elements for Co Ni and Cu Operatingconditions were 20 kV and 2 nA sample current with beamdefocused at not less than 10 120583m forNa K Si and Al in orderto minimise the loss of alkali elements and better evaluate Sicontents and at 20 kV and 30 nA for other elements X-raycounts were converted to oxide weight percentages with thePAP (CAMECA) correction programThe detailed analytical

conditions used and the precision accuracy and detectionlimits of EMPA are given in Silvestri and Marcante [7] asthe present samples were subjected to the same analyticalprotocol It is stressed here that the precision and accuracyof data were calculated by comparisons with measures onthe international reference standard Corning glass B inthe same analytical conditions as our Greek samples Theprecision of EMPA data was generally between 05 and10 for major and minor elements respectively Accuracy

4 Journal of Chemistry

Table 2 Isotopic and chemical composition of Roman and late Antique glasses from Thessaloniki Agora 1stndash6th century AD in age Notethat CoO and NiO contents are not reported because they are lower than EMPA detection limits for all samples (LOD of CoO and NiO =003wt)

Sample 12057518O SiO2 Na2O CaO Al2O3 K2O MgO FeO TiO2 MnO P2O5 SO3 Cl CuO ZnO SnO2 Sb2O3 PbONumber (VSMOW) Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt1-1 155 6617 1690 860 268 065 146 122 018 164 013 035 068 lt003 lt004 lt004 lt004 lt0082-1 156 6465 1496 614 316 094 149 111 020 148 065 016 065 067 004 089 lt004 2903-1 155 7148 1540 742 244 037 059 058 009 055 002 024 096 lt003 lt004 lt004 lt004 lt0084-1 156 6424 988 574 159 1147 348 030 003 lt005 130 007 064 lt003 lt004 lt004 009 lt0085-1 154 6768 1694 708 273 057 096 159 028 109 007 023 109 lt003 lt004 lt004 lt004 lt0086-1 155 7298 1700 498 209 056 051 029 009 lt005 001 022 090 lt003 lt004 lt004 025 lt0087-1 156 6543 1976 654 238 040 108 114 026 112 002 027 160 014 lt004 lt004 lt004 0338-1 155 6714 1683 786 292 091 129 165 020 145 026 025 054 lt003 lt004 lt004 lt004 lt0089-1 156 6553 1733 784 295 085 141 139 019 167 026 030 053 lt003 lt004 lt004 lt004 lt00810-1 155 7651 967 811 025 378 103 006 lt004 lt005 006 040 019 lt003 lt004 lt004 lt004 lt008

155 plusmn 007permilmean isotopic composition

was better than 1 for SiO2 Na2O and FeO better than 5for CaO K2O P2O5 and Sb2O3 and not worse than 12 forother major and minor elements

The chemical and mineralogical compositions of chertsamples were obtained bymeans of X-ray fluorescence (XRF)and X-ray powder diffraction (XRPD) respectively

X-ray fluorescence (XRF) was carried out on a PhilipsPW 2400 instrument equipped with a Rh tube with a ratedcapacity of 3 kW (60 kV125mA max) Three primary col-limators (150 300 and 700120583m spacing) and four analyticalcrystals (TlAp100 LiF200 Ge111 and PE002) were selectedThe spectrometer was interfaced with a personal computerwith SuperQ software (Philips) Instrumental parametersand analytical conditions are detailed in Alberta et al [8]Geological reference standards were used for calibration [9]Precision was better than 06 for major andminor elementsand about 3 for trace elements XRF accuracy was checkedby reference standards [9] and was within 05 wt for Silower than 3 for othermajor andminor elements and lowerthan 5 for traces The lowest detection limits of XRF werewithin 002wt for Al2O3 MgO and Na2O within 04 wtfor SiO2 and within 0005wt for TiO2 Fe2O3 MnO CaOK2O and P2O5 and range from 3 to 10 ppm for trace elementsFor this type of analysis chert fragments were crushed in anagatemortarThe resulting powders were heated in an oven at860∘C for 20min and then at 980∘C for 2 hours and the losson ignition (LOI) was determined The powders were thenmixed with Li2B4O7 at a 1 10 ratio and beads were prepared

XRPD data were obtained on a computer-controlledPhilips XrsquoPert PRO with Bragg-Brentano 120579-120579 geometry Thenormal-focus CuX-ray tube (CuK1205721 120582= 0154056 nm) oper-ated at 40KV and 20mA Data were recorded in the 2∘ndash70∘2120579 range in step-scan mode with step width increments of002∘ and a step counting time of 10 s Data were processedby the XrsquoPert HighScore (PANalytical copyright) 2120579 and 119889values were calculated with the second-derivative algorithmof Savitzky andGolay [10] All XRPDdiffraction profiles werecarried out on about 500mg of samples finely ground into anagate mortar

It should be stressed here that XRPD analyses werecarried out on all the chert samples while XRF analyseswere carried out only on samples Trd 1-2 and Trd 1-5 whichare representative of the two mineralogical compositionsidentified

3 Results and Discussion

31 Results The ten samples from the Thessaloniki Agorashow an extremely homogeneous oxygen isotopic composi-tion (154ndash156permil Table 2) All the samples from the churchof Maroneia 4thndash6th centuries AD in age also have isotopiccompositions ranging from 152 to 160permil with mean valueequal to 156plusmn025permil(Table 3)Theirmean isotopic values arepractically identical to those of the first set of samples fromThessaloniki although the range of values from Maroneia isslightly largerThe isotopic results obtained on the remainingnineteen glasses from Thessaloniki indicate that only ninesamples (4-3 5-3 7-3 4-4 5-4 6-4 7-4 11-4 and 14-4)have values very close to those measured in samples fromThessaloniki Agora and Maroneia (Table 4)

In contrast with the remarkable isotopic homogeneity ofthemajority ofGreek glass samples (2939 samples) chemicalcompositions are rather heterogeneous (Tables 2 3 and 4)In particular samples 1-1 5-1 8-1 9-1 (Table 2) 4-3 6-4 11-4 and 14-4 (Table 4) from Thessaloniki and all the samplesfrom Maroneia (Table 3) show SiO2 contents ranging from6448 to 6768wt Na2O from 1636 to 1846wt CaOfrom 702 to 907wt and Al2O3 from 229 to 292wtK2O and MgO contents are both lower than 15 wt in allthe considered samples although MgO is higher than K2O(MgO = 125 plusmn 015wt versus K2O = 070 plusmn 013wt)Thisgroup of samples also shows the highest iron titanium andmanganese contents (FeO from 080 to 212 wt TiO2 from014 to 037wt and MnO from 096 to 265wt) andnondetectable trace elements

The other glass samples from Thessaloniki (2-1 3-1 6-17-1 5-3 7-3 4-4 5-4 and 7-4) whose 12057518O is in the range153ndash156permil (Tables 2 and 4) also show comparable SiO2

Journal of Chemistry 5

Table 3 Isotopic and chemical composition of glasses fromMaroneia 4thndash6th centuries AD in age Note that CoO NiO CuO ZnO SnO2Sb2O3 and PbO contents are not reported because they are lower than EMPA detection limits for all samples (LOD of CoO NiO and CuO =003 wt LOD of ZnO SnO2 Sb2O3 = 004 wt LOD of PbO = 008 wt)

Sample 12057518O SiO2 Na2O CaO Al2O3 K2O MgO FeO TiO2 MnO P2O5 SO3 ClNumber (VSMOW) Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt1-2 154 6711 1739 784 229 061 110 106 015 154 007 030 1022-2 155 6623 1780 783 270 076 123 133 017 123 015 031 0923-2 156 6462 1770 898 240 072 147 104 016 182 012 034 0924-2 159 6564 1846 795 270 082 121 138 016 096 013 032 0915-2 156 6570 1738 825 238 059 121 088 015 169 009 034 0956-2 156 6679 1717 750 253 060 125 098 016 184 008 030 1007-2 157 6463 1796 907 257 071 150 110 018 172 013 033 0928-2 152 6556 1756 752 250 065 125 093 017 234 009 029 1019-2 160 6613 1814 783 273 084 122 128 015 099 016 034 09010-2 153 6659 1636 859 240 069 111 088 017 160 011 036 087

156 plusmn 02permilmean isotopic composition

Table 4 Isotopic and chemical composition of Roman and late Antique glasses from Thessaloniki 1stndash6th centuries AD in age Sampleswith moderate and strong 18O enrichment are in italics and bold font respectively Note that NiO ZnO and SnO2 contents are not reportedbecause they are lower than EMPA detection limits for all samples (LOD of NiO = 003wt LOD of ZnO and SnO2 = 004wt)

Sample 12057518O SiO2 Na2O CaO Al2O3 K2O MgO FeO TiO2 MnO P2O5 SO3 Cl CoO CuO Sb2O3 PbONumber (VSMOW) Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt1-3 226 6746 1300 974 117 485 201 058 006 096 069 007 128 lt003 lt003 lt004 lt0082-3 225 6731 1320 980 115 477 200 057 005 096 066 007 129 lt003 lt003 lt004 lt0083-3 186 6695 1946 671 221 043 096 063 010 127 010 025 143 lt003 lt003 lt004 lt0084-3 158 6420 1767 702 285 040 128 212 037 265 010 040 123 lt003 lt003 lt004 lt0085-3 156 6789 1617 864 268 053 083 044 007 136 007 035 119 lt003 lt003 lt004 lt0086-3 173 6492 1919 821 232 059 106 094 014 158 007 045 087 lt003 lt003 lt004 lt0087-3 152 7162 1553 647 263 065 042 026 004 033 009 003 106 lt003 lt003 lt004 lt0083-4 161 6478 1862 775 237 059 119 115 015 152 005 044 093 lt003 lt003 lt004 lt0084-4 153 6732 1696 785 252 031 088 072 022 161 001 028 136 lt003 lt003 lt004 lt0085-4 153 6678 1796 652 240 050 095 079 021 166 002 029 119 lt003 lt003 lt004 lt0086-4 153 6525 1746 783 246 062 100 080 015 192 005 047 099 lt003 lt003 004 lt0087-4 153 6580 1876 630 189 054 087 067 010 077 004 031 146 lt003 178 lt004 lt0088-4 156 6156 1248 1003 390 495 193 079 017 073 043 014 088 lt003 lt003 004 0509-4 227 6780 980 921 110 545 235 051 005 067 052 010 091 lt003 lt003 004 lt00810-4 164 6546 1983 636 248 049 116 117 016 011 001 052 123 004 021 lt004 06311-4 154 6451 1791 864 265 076 118 143 014 066 011 045 098 lt003 lt003 lt004 lt00812-4 205 6272 1179 945 134 440 204 092 006 438 039 013 105 lt003 lt003 006 lt00813-4 173 6444 1268 964 234 423 207 076 012 121 042 016 101 lt003 lt003 004 01414-4 156 6448 1781 723 258 079 134 197 015 115 014 054 098 lt003 lt003 lt004 lt008

Na2O CaO K2O and MgO contents with the previousglass samples although they differ in contents of colour-ingdecolouring elements for example iron copper man-ganese and antimony and minor elements for example tinand lead (Tables 2 and 4) In particular samples 5-3 4-4 and5-4 show concentrations of manganese higher than 1 wtwhereas sample 6-1 has nomanganese but antimony (Table 2)Instead samples 3-1 and 7-3 do not reveal any manganeseor antimony (Tables 2 and 4) Sample 2-1 from ThessalonikiAgora has relatively high concentrations of CuO SnO2 PbO

and P2O5 (Table 2) The chemical composition of sample7-1 is comparable with that of sample 2-1 except for thelower copper and lead contents (Table 2) Lastly samples 4-1 and 10-1 from Thessaloniki Agora which have comparable12057518Ovalues show chemical compositions different from eachother except for the similar (and relatively low) content ofsodium (about 10 wt Na2O) and the absence of manganeseand trace elements in both samples In particular sample 4-1has lower SiO2 and CaO and higher Al2O3 K2O MgO FeOP2O5 and Cl than sample 10-1 (Table 2)

6 Journal of Chemistry

Table 5 12057518O(VSMOW) of chert samples from the quarries in Triadiof Thessaloniki (Central Macedonia Greece)

Samples 12057518O(VSMOW) MeanTrd 1-1 250 251 250Trd 1-2 234 235 234Trd 1-4 236 238 237Trd 1-5 260 261 260Trd 2-1 242 244 243Trd 3-1 261 260 260Trd 3-2 258 260 259Trd 5-2 225 223 224

Mean value 246 plusmn 14permil

Lastly sample 8-4 fromThessaloniki with 12057518O equal to156permil is characterised by lower silicium and sodium con-tents and higher calcium aluminium potassium magne-sium and phosphorous contents (Table 4) than other glasseswith comparable isotopic composition

In addition to samples with isotopic signatures rangingfrom 152 to 160permil the isotopic data indicate that foursamples fromThessaloniki are heavily enriched by about 7permilsample 12-4 has 12057518O equal to 205permil and samples 1-3 2-3and 9-4 have values from 225 to 227permil Finally other fivesamples fromThessaloniki (3-3 6-3 3-4 10-4 and 13-4) showmoderate 18O enrichment with values between 161 and186permil (Table 4)

The chemical analyses of the heavily enriched glass(Table 4) show that all samples are characterised by higherCaO K2O MgO and P2O5 and lower Na2O and Al2O3contents than other Greek samples with lower isotopic com-position In addition sample 12-4 also has exceptionally highmanganese (MnO = 438wt Table 4)

The samples with moderate 18O enrichment show quitevariable chemical compositions but comparable to those ofsamples with lower and higher isotopic compositions Sam-ples 3-3 (12057518O= 186permil) and 10-4 (12057518O= 164permil) have chem-ical compositions comparable to those of samples 5-3 4-4and 5-4 although sample 10-4 has very little Mn and highCu and Pb (Table 4) Sample 6-3 (12057518O = 173permil) is similarin chemical composition to samples 1-1 5-1 8-1 91 4-3 6-4 11-4 and 14-4 from Thessaloniki (Tables 2 and 4) and allthe samples from Maroneia (Table 3) Finally the chemicalcomposition of sample 13-4 (12057518O = 173permil) is very similar tothose of the heavily enriched glass as deduced from itslow Na2O and Al2O3 and high CaO K2O MgO and P2O5contents (Table 4)

The isotopic data obtained on the chert samples from thequarries in Triadi ofThessaloniki show that mean 12057518O value(equal to 246 plusmn 14permil Table 5) is comparable to those ofGreek glass samples heavily enriched (mean 12057518O value =221 plusmn 11permil) Mineralogical data obtained by means ofXRPD show chert samples are a mixture of quartz andgoethite (semiquantitative contents of the two phases 94quartz and 6 goethite) except for sample Trd 1-5 composedof only quartz (Figure 1)

XRF data furtherly confirm the mineralogical composi-tions sample Trd 1-2 being almost entirely composed of SiO2and Fe2O3 and Trd 1-5 of only SiO2 (Table 6)

32 Discussion The majority of the analysed samples fromThessaloniki and all the samples from Maroneia have ahomogeneous oxygen isotopic composition (12057518O value =156 plusmn 025permil Table 2 and Figure 2) which is equal orvery close to the mean value of ldquoRomanrdquo glass as deducedfrom a set of isotopic measurements on glass from Europedated from the 1st to the 4th centuries AD which show arelatively narrow range of 12057518O (from about 154permil to 160permil)[2 3] Similar results (Figure 2) were also obtained for lateAntiqueearly Medieval samples from Grado and Vicenzatwo sites in Northern Italy [3] and for coeval glass from theNear East [11 12]

These similarities may be explained by assuming thatthe Greek glass samples were produced with raw materialswith equal or very similar oxygen isotopic compositionSand from the rivers Belus in Palestine and Volturno inItaly mentioned by Pliny the Elder in Naturalis Historia asmaterials for making glass is suitable for glass productionand has the same oxygen isotopic composition when theVolturno sandundergoes selective grinding [3] It follows thatglass produced with either Belus or Volturno sand as networkformer and natron as flux is practically indistinguishablefrom the oxygen isotopic point of view Consequently theisotopic composition of most of the Greek samples in Tables2 3 and 4 cannot help to distinguish among glass samplesimported from Italy or the Near East or glass samplesproduced inGreek secondary glassworkshops bymelting rawglass from the geographic point of view a Levantine originfor the Greek glass samples is quite reasonable This origin isreinforced by data reported in Brill [13] on five cullets froman ancient glass workshop at Jalame in western Galilee (3rd-4th centuries AD) The author suggests that the silica usedfor these cullets came from sand taken from the mouth ofthe Belus and that the oxygen isotopic composition of quartzwas enriched in 18O by the calcium carbonate contained inthe sand in the form of sea shells with natron as flux The12057518O values of the Jalame glass are slightly lower than thoseof Greek samples and range from about 14 to 15permil (Figure 2)Although the use of various other raw materials cannot becompletely excluded this small difference may be explainedby amounts of natron used for melting which are slightlysmaller in Jalame than in Greek glass samples The oxygenisotopic study carried out by Silvestri et al [3] on Romannatron glass demonstrated the ldquopositive natron effectrdquo that isit is presumed that flux which has very positive 12057518O valuescaused 18O enrichment in the final glass as confirmed bythe plot of Na2O versus 12057518O which clearly shows a positivecorrelation Other glass samples from the Near East have12057518O values close to those of our samples showing ldquoRomanrdquovalues (Figure 2) These samples measured by Leslie et al[12] came from different locations three from the BethShersquoan in Israel (6th-7th centuries AD) mean value 146permilthree from Tel el-Ashmunein in Egypt (8th-9th centuries)mean value 148permil and three from Carthage in Tunisia

Journal of Chemistry 7

10 20 30 40 50 60 70

Cou

nts

0

TRD-1-2

Peak list

Goethite syn FeO(OH)

50000

100000

150000

Quartz low SiO2

Position (∘2휃) (copper (Cu))

(a)

TRD-1-5

10 20 30 40 50 60 70

Cou

nts

Peak list

0

100000

200000

Quartz low SiO2

Position (∘2휃) (copper (Cu))

(b)

Figure 1 XRPD patterns of chert samples named Trd 1-2 (a) and Trd 1-5 (b) representative of the twomineralogical compositions identified

(4thndash6th centuries) mean value 150permil All these samplesare obtained using natron from the evaporitic lakes of WadiNatron in Egypt The provenance of sand from a relativelyshort stretch of the eastern Mediterranean coast is suggestedfor the Beth Shersquoan samples and the similarity between thedelta values of the Tel el-Ashmunein and Carthage samplesis explained by their production with the same Egyptiansand The isotopic similarity among these three groups ofsamples can be explained taking into account a commonprovenance for natron and that Levantine sand comes fromEgypt and is transported up to the eastern Mediterraneancoast by sea currents [14 15] therefore the use of sandand flux with similar provenance yields glass samples withsimilar isotopic compositions The same source may thusbe hypothesised for the Greek glass samples analysed hereHowever it should be stressed that natural natron depositsin the region of Macedonia in northern Greece were well-known in the time of Plato (5th century BC) and werealso described by Pliny the Elder in his Naturalis HistoriaeHatzopoulos and Loukopoulou [16] identified Lake Chalastra(so-called in antiquity that is the place where the ldquoCha-lastraion nitronrdquo formed and dissolved over a period of afew days) as the modern lake of Picrolimni located about20 km NW of Thessaloniki The geochemical conditionsresponsible for the formation of ldquoChalastraion nitronrdquo haverecently been studied and discussed by Dotsika et al [17]The salts deposited by the lake brine were mineralogicallyidentified by XRD analysis and include not only calcite anddolomite but also trona (Na2CO3sdotNaHCO3sdot2H2O) burkeite(Na2CO3sdot2Na2SO4) and halite (NaCl) thus confirming themineralogical similarity between these deposits and thosefrom Wadi Natron in Egypt However the oxygen isotopiccompositions determined on the Picrolimni salt deposits

range from about 11 to 25permil (VSMOW) much lower than thevalues for Wadi Natron (about 34 to 40permil [2 3]) Thereforein the case of our samples use of ldquoChalastraion nitronrdquo as fluxcan hardly be considered

In contrast with the remarkable isotopic homogeneity ofthe majority of Greek samples (2939 samples) the chemicalcomposition is rather heterogeneous (Tables 2 3 and 4)although they are all obtainedwith natron as flux having bothK2O and MgO contents lower than 15 wt In particularsamples 1-1 5-1 8-1 9-1 4-3 6-4 11-4 and 14-4 fromThessaloniki (Tables 2 and 4) and all the samples fromMaroneia (Table 3) show the HIMT (High Iron Magnesiumand Titanium) signature This reference group is defined byhigh levels of iron (ge07 wt)manganese (usually sim1-2 wt)magnesium (usuallyge08 wt) and titanium (ge01 wt) andits yellow-green colour is due to the amount of iron sugges-tive of a relatively impure sand source [18] These also are thekey characteristics of Greek glass samples which have highFeO (120 plusmn 031wt) MnO (154 plusmn 035wt) MgO (124 plusmn016wt) and TiO2 (018plusmn005wt) contentsThe acronymHIMT was first applied by Freestone [19] to raw glass fromCarthage and glass vessels from Cyprus [20] although glasswith high contents of iron manganese and titanium wasalready identified by Sanderson et al [21] However all theGreek samples (except 4-3) containing about 50ndash60 of theamount of iron titanium and manganese oxides measuredin ldquotypicalrdquo HIMT glass such as Group 1 of Foy et al [22](about 121 plusmn 031wt as FeO 017 plusmn 003wt as TiO2and 151 plusmn 037wt as MnO versus 2 plusmn 08wt as FeO05 plusmn 01wt as TiO2 and 22 plusmn 04wt as MnO for Greeksamples and Group 1 resp) show a better fit with ldquoGroup 2rdquoof Foy et al [22] whichmay be considered as a ldquoweakrdquo HIMTglass [18] due to lower contents of the key oxides of HIMT

8 Journal of Chemistry

Table6Ch

emicalcompo

sitions

ofchertsam

plesn

amed

Trd1-2

andTrd1-5

representativeof

thetwomineralogicalcompo

sitions

identifi

ed(X

RFdataL

OIlosson

ignitio

n)N

otethat

GaYNbLaC

eandUcontentsaren

otrepo

rted

becausetheyarelow

erthan

XRFdetectionlim

itsfora

llsamples

(LODof

Ga=

5ppm

LODof

YNbandU=3p

pmLODof

LaandCe=

10pp

m)

Sample

SiO2

TiO2

Al 2O3

Fe2O3

MnO

MgO

CaO

Na 2O

K 2O

P 2O5

LOI

ScV

CrCo

Ni

CuZn

RbSr

ZrBa

Nd

PbTh

Num

berWt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

Trd1-2

9068

001

021

713

015

037

012

005

001

002

218

9314

507

124

146

1846

78

920

1912

7Trd1-5

9998lt00

05lt00

2lt00

05lt00

05lt00

2lt00

05lt00

2lt00

05lt00

05000lt3lt3lt3lt3lt3lt3lt3lt3lt3lt3lt10lt10lt10lt3

Journal of Chemistry 9

10 11 42 10 9 5 9 16 414

15

16

17

18

19

Number of samples

훿18O

(VSM

OW

)(permil

)

Figure 2 Comparisons among 12057518O(VSMOW) values of natron glasssamples [open symbols Thessaloniki Agora (◻) Maroneia ()Thessaloniki various sites (998779)Thessaloniki glass withmoderate 18Oenrichment (I)] and those already reported in the literature [fullsymbols Roman glass from Europe (◼) [2] Roman glass from IuliaFelix (X) [3] 4th century AD glass from Jalame (998771) [2] HIMTglass from Carthage and Levantine natron glass (bold plus sign)[12] late Antique-earlyMedieval glass fromGrado ad Vicenza (boldmultiplication sign) [3]] Number of analysed samples is also shown

glass (Figure 3) Instead sample 4-3 has FeO TiO2 andMnO contents (Table 4) perfectly comparable with ldquotypicalrdquoHIMT glass [18 22] In general HIMT glass has also beenidentified in Britain [18] Egypt [23] France [22] Italy [24ndash29] Cyprus [20 30] Carthage [31] Bulgaria [32] andAlbania[33] The chemical and isotopic signatures of HIMT glass aresuggestive of continental sand sources of high maturity richin heavy minerals and located in the Near East probablyin Egypt [12 31 34] As regards the dating of the referencegroups in general terms the HIMT group is probably morecharacteristic of the period from the mid-4th century ADonwards although according to current research its compo-sition seems to have continued after the 5th century [18]In addition according to Schibille et al [31] ldquoGroup 2rdquo isdated to the 5th-6th centuries and is thus coeval with theglass from Maroneia Consequently the age of Thessalonikiglass samples similar in composition to those of ldquoGroup 2rdquois constrained to the late Antique period

The other glass samples from Thessaloniki (2-1 3-1 6-17-1 5-3 7-3 4-4 5-4 and 7-4) whose 12057518O is in therange of ldquoRomanrdquo values also show the chemical compo-sition typical of Roman glass [35] although they differ incontents of manganese and antimony (Figure 3) and traceelements In particular samples 3-1 5-3 4-4 and 5-4 showMnO gt 05 wt which suggests its intentional addition asa decolouriser [36] whereas sample 6-1 has no manganesebut antimony (Table 2) As these two elements the principal

decolourisers used between the 1st and 4th centuries ADwere both predominant from the late 1st to the 3rd centuriesand as the use of manganese increased from the end of the3rd to the 4th century [36ndash38] the age of these samples isconstrained accordingly Instead samples 3-1 and 7-3 do notreveal any intentional addition of decolouriser having noantimony and MnO lt 05 wt (Tables 2 and 4) Sample 2-1from Thessaloniki Agora has relatively high concentrationsof CuO SnO2 PbO and P2O5 (Table 2) suggesting theinclusion of cullet perhaps coloured and opaque mosaictesserae containing high quantities of one or more of theseelements in the glass batch The chemical composition ofsample 7-1 is not far from that of sample 2-1 although the con-centrations of copper and lead are much lower than those insample 2-1 (Table 2) This indicates that the presence ofthe above elements is due to recycling of earlier colouredglass because they occur in concentrations higher than thoseattributable to impurities in the raw materials but too low tohave any technological significance [39] Conversely the highCu in sample 7-4 not associated with high Sn Co Pb Sband Zn (Table 4) suggests that this element was intentionallyadded to produce the aquamarine colour

Lastly chemical similarities between samples 4-1 and 10-1from Thessaloniki Agora and data reported in the literatureare difficult to establish Sample 4-1 seems quite comparablewith some soda-potash-lime glass from the 14th-centuryworkshop at Saint-Chely (France) Two different hypothesesboth equally valid from an analytical point of view are pro-posed to explain the peculiar chemical composition of theseLate Medieval French samples [40] both soda and potashash were used by the glass-workers soda ash remaining themain component recycled glass from the surrounding areaswith both potash and soda ash compositions was used asrawmaterials Sample 10-1 also approaches although not per-fectly the composition of ldquomixed soda-potash glassrdquo dated toLate Bronze age [40] and the oxygen isotopic data obtained byBrill et al [2] on some Late Bronze age objects are also quitecomparable with that of sample 10-1 On the contrary oxygenisotope data on samples with chemical composition similarto sample 4-1 are unfortunately still lacking although dataon Medieval soda ash and late Medieval and modern potashash glass are systematically lower and range from about 12to 145permil [2 3] In any case both isotopic and chemical datasuggest that the age proposed for samples 4-1 and 10-1 fromThessaloniki Agora should be revised

The chemical analyses of the heavily enriched glass(Table 4) show that all samples were melted with soda ashas flux their K2O MgO and P2O5 contents being higherthan those of the other samples (Figure 3) The low Al2O3content suggests that as well as flux a different silica sourcewas used to produce these samples Leslie et al [12] reportsome highly variable isotopic results from glass samples10thndash13th centuries in age from Rarsquos al-Hadd (Oman) one ofwhich is close to 20permil (Figure 4) Heavily enriched 12057518Ovalues which range from 216 to 226permil have already beenmeasured by Brill et al [2] on glass samples from Nimrud(Iraq) dated to the 7th century BC the author obviouslyconcluded that ldquothese glasses must represent a glassmaking

10 Journal of Chemistry

60 64 68 72 76 808

12

16

20N

a 2O

(wt

)

SiO2 (wt)

(a)

0 2 4 6

Natron

Soda plant ash

0

1

2

3

4

MgO

(wt

)

K2O (wt)

(b)

4 6 8 10 120

1

2

3

4

Al 2O

3 (w

t)

CaO (wt)

(c)

0 05 1 15 2 250

1

2

3

4

5

MnO

(wt

)

FeO (wt)

(d)

Figure 3 Na2O versus SiO2 (a) MgO versus K2O (b) Al2O3 versus CaO (c) and MnO versus FeO (d) contents of Greek glass samplessubdivided by provenance Thessaloniki Agora () Maroneia (I) Thessaloniki various sites (998779 natron glass 998771 soda ash glass) Meanchemical compositions and standard deviations of main compositional natron groups identified in literature and comparable with Greeksamples are also shown ldquoRomanrdquo glass (bold plus sign) Group 2 (bold multiplication sign) [22 35]

tradition thatmade use of some particular rawmaterialrdquo Twosamples from Aphrodisias (Turkey) 6th-7th centuries ADin age also yielded 12057518O values of about 234permil (Figure 4)All the samples reported in the literature with very positive12057518O values were obtained with soda ash as flux althoughthey show lowerK2OMgOandhigherNa2OK2Oratios thanGreek samples suggesting the use of different kinds of plantash

In Europe and Mediterranean area soda ash glass datesfrom the 9th century AD onwards [4 41] This wouldexclude a Roman age for Greek soda ash samples unlessthey were produced with raw glass imported from areas suchas Mesopotamia and Iran where plant ash continued to beused as flux in glass production throughout the period ofnatron dominance in the West [4] However so far chemicalcomparisons with 3rdndash7th-century soda ash glass from Iraq

Journal of Chemistry 11

7 6 2 8 6

12

16

20

24훿18O

(VSM

OW

)(permil

)

Number of samples

Figure 4 Comparisons among 12057518O(VSMOW) values of plant ash glasssamples [open symbols Thessaloniki various sites (◻)] and thosealready reported in the literature [full symbols glass from Nimrudand Aphrodisias (◼) [2] glass from Rarsquos al-Hadd (e) and Levantinesoda ash glass (X) [12] Medieval soda ash glass from Italy (998771) [3]]Number of analysed samples is also shown

[42 43] have not shown any consistency with Greek samplesIn addition the heavily enriched 12057518O values do indicatethat their raw materials differed from those normally used inRoman andMedieval glass production and this wouldmatchthe possibility of the different origin of these materials Theuse of ash as flux may cause some 18O enrichment when theash is particularly rich in carbonate bicarbonate and hydrate[4] but hardly to this extent Previous oxygen isotopic dataobtained on Medieval soda ash glass from the Western andEastern Mediterranean (Figure 4) indicate that the additionof ash did not contribute to isotopically heavy oxygen and the12057518Ovalues essentially reflect the silica source (eg [2 3 12])In the case of Greek heavily enriched glass the silica source isdifficult to identify taking into account the fact that quartzwith anomalously heavy isotopic composition is uncommoninmagmatic sedimentary or metamorphic rocks Due to thelarge oxygen isotopic fractionation between SiO2 andwater atlow temperatures biogenic silica and chert have the highest18O16O ratios observed in rocks [44] Therefore the Greeksamples with high isotopic values may be the product oflocal glass workshops which used raw materials composedof chert with the addition of ash probably obtained fromvarious plant species other than those considered by Titeet al [4] or differently pretreated The isotopic chemicaland mineralogical data obtained on a selection of chertsamples from the quarries in Triadi of Thessaloniki (CentralMacedonia Greece) furtherly support the hypothesis of localproduction at least if we consider sample Trd 1-5 composedof only quartz

In the case of samples with moderate 18O enrichmentseveral causes must be considered to explain their valuesSample 3-3 (12057518O= 186permil) has a chemical composition quiteclose to that of Roman glass decolourised by the addition ofMn [45] sample 6-3 (12057518O= 173permil) is chemically comparableto ldquoGroup 2rdquo of Foy et al [22] and its suggested age (6thcentury AD) matches the chronological diffusion of the ref-erence group However both samples have 12057518O higher thanthe average ldquoRomanrdquo or ldquoHIMTrdquo values

In view of the high Na2O content of samples 3-3 and 6-3(Table 4) 18O enrichment may be explained by remelting ofprevious glass with addition of further amounts of natron asflux which causes an increase in Na2O concentration and inthe 18O content of the final products

Apart from their slightly higher 12057518O values (161 and164permil resp) samples 3-4 and 10-4 show quite differentchemical compositions Sample 3-4 is chemically comparablewith ldquoGroup 2rdquo [22] the chronological diffusion ofwhich alsomatches the age proposed (5th-6th centuries AD) whereassample 10-4 is similar to Roman glass 1stndash3rd centuries Adin age although the presence of Cu and Pb may also indicaterecycling of coloured and opaque glass as in the case ofsample 7-1 Both samplesmay be produced in local secondaryworkshops by recycling previous glass (perhaps from theLevantine area) with the addition of further amounts ofnatron as flux as suggested by their high Na2O content(Table 4) thus increasing the 18Ocontent of the final product

According to its chemical composition sample 13-4(Table 4 12057518O= 173permil) was obtained with soda ash as flux asdeduced from its high K2O MgO and P2O5 contents Wesuggest a different starting material for this sample as in thecase of other soda plant ash glass identified in the Greekassemblage

Lastly sample 8-4 from Thessaloniki has 12057518O of 156permilthat is within the average Roman values suggesting the use ofBelus or Volturno sand and Egyptian natron as rawmaterialsbut its chemical composition is comparable to that of glassproduced with soda plant ash as flux The chronologicaldiffusion of soda ash glass in Europe andMediterranean area[4 41] excludes a Roman age for this sample and chem-ical comparisons with 3rdndash7th-century soda ash glass fromIraq [42 43] where plant ash continued to be used as fluxthroughout the period of natron dominance in the West [4]have not shown any consistency with the present sampleTherefore great uncertainty remains in the case of sample 8-4 as regards both its age and provenance also in view of theheavily enriched oxygen signatures of other soda ash samplesidentified here (Table 4) However sample 8-4 differs fromthe others due to its lower SiO2 (616 wt) and higher Al2O3(390wt) which suggest a different silica source probably asilica sand rich in feldsparsThis source may be characterisedby a less positive oxygen signature probably related to thefeldspars content of the sand which influences the 18Ocontent of the final productThis hypothesis is also supportedby the isotopic and chemical signatures of sample 13-4Obtained again with soda plant ash as flux this sample hasAl2O3 content intermediate between that of sample 8-4 andall other Greek soda ash samples and consequently shows anintermediate 12057518O value

12 Journal of Chemistry

4 Conclusions

The results of the present study emphasize the importanceof measuring the oxygen isotopic and chemical compositionsof glass samples in order to constrain some features such asage raw materials and production technology Comparisonsof our isotopic and chemical data with those reported in theliterature particularly in the case of glass from the Levantinearea are of particular interest as regards the trading ofraw glass to secondary workshops in Greece although forsome samples obtained with soda ash as flux and heavilyenriched in 18O production from local raw materials cannotbe completely excluded

In summary the thirty-nine glass samples from northernGreece studied here have oxygen isotopic compositionswhich allow them to be subdivided into three groups

The first is composed of twenty-nine samples (severalfrom Thessaloniki and all those from Maroneia) with 12057518Ovalues equal or very close to themean value of Roman glassesfrom European and Middle Eastern areas These similaritiesimply their production with raw materials with equal or veryclose oxygen isotopic composition such as sand from therivers Belus in Palestine and Volturno in Italy as suggestedby Pliny the Elder In contrast with the remarkable isotopichomogeneity heterogeneous chemical compositions allowthe subdivision of these samples into several subgroupswhich are compared with major compositional groups iden-tified in the Western Mediterranean during the first millen-nium AD

Seven samples from Thessaloniki and all the samplesfrom Maroneia show chemical similarity with ldquoGroup 2rdquo ofFoy et al [22] while one sample shows chemical simi-larity with HIMT glass Accordingly their age should beconstrained to the late Antique period for the Thessalonikiglass and confirmed for the Maroneia samples (ie 4thndash6thcenturies AD) Nine samples from Thessaloniki are chemi-cally comparable with Roman glass although they differ incolouringdecolouring elements and recycling indicators Inparticular in some samples the identification of manganeseintentionally added as a decolourant allows us to constraintheir age according to the chronological diffusion reported inthe literature of this decolourant that is from the 3rd to 4thcenturies AD Lastly three samples from Thessaloniki(1stndash6th centuries AD) with 12057518O values comparable withldquoRomanrdquo values have chemical compositions very differentfrom ldquotypicalrdquo Roman glass suggesting different productiontechnologies

The second isotopic group is composed of four samplesfrom Thessaloniki showing heavily enriched 12057518O values(205 to 227permil) their chemical analyses indicate that theywere obtained using soda ash as flux which has little effect onthe final oxygen isotopic composition of glass These high12057518O values may be explained by the use of silica rawmaterials with heavy 18O enrichment such as chert which isalso found in the Thessaloniki region Therefore these sam-ples may be the product of local glass factories

The third group is composed of five samples from Thes-saloniki showing moderate 18O enrichment (161 to 186permil)

From the chemical point of view four samples are natronglass with compositions similar to Roman or ldquoweakrdquo HIMTgroups and one is a soda ash glass In the case of natron glassthe moderate 18O enrichment may be obtained by recyclingglass (perhaps from the Levantine area) in local secondaryworkshops with the addition of further amounts of natron asflux as suggested by their high Na2O contents In the case ofsoda ash themoderate 18O enrichment with respect to otherGreek soda ash glass may be due to the use of less positivesilica source

In conclusion these interesting results the first obtainedon glass samples from northern Greece support trades andcommercial exchanges between theNear East andGreece andsuggest although further data are required to confirm it thatthe ldquofingerprintrdquo ofGreek glass production could be related tothe use of local chert and soda ash as possible raw materials

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

The authors are grateful to D Grammenos director ofthe Archaeological Museum of Thessaloniki for providingglass samples from Thessaloniki R Carampin (Istituto diGeoscienze e Georisorse Sezione di Padova CNR) F Gallo(Dipartimento dei Beni Culturali Universita di Padova) andD Pasqual (Dipartimento diGeoscienze Universita di Padova)are thanked for their kind support to execution of chemicalanalyses Financial support was provided by ldquoEx 60rdquo fundsof the University of Padova (principal investigator AlbertaSilvestri)

References

[1] R Newton andD DavisonConservation of Glass Butterworth-Heinemann Oxford UK 1999

[2] R H Brill R N Clayton T K Mayeda and C P StapletonldquoOxygen isotope analyses of early glassesrdquo in Chemical Analysesof Early Glasses R H Brill Ed vol 2 pp 303ndash322 CorningMuseum of Glass New York NY USA 1999

[3] A Silvestri A Longinelli andGMolin ldquo12057518Omeasurements ofarchaeological glass (Roman toModern age) and rawmaterialspossible interpretationrdquo Journal of Archaeological Science vol37 no 3 pp 549ndash560 2010

[4] M S Tite A Shortland Y Maniatis D Kavoussanaki and S AHarris ldquoThe composition of the soda-rich and mixed alkaliplant ashes used in the production of glassrdquo Journal of Archae-ological Science vol 33 no 9 pp 1284ndash1292 2006

[5] C Antonaras ldquoGlass working in Roman and early ChristianThessaloniki older and more recent findsrdquo in Proceedings of theHistory Technology and Conservation of Ancient Metals Glassesand Enamels International Symposium Athens Greece Novem-ber 2011

[6] I Friedman and J R OrsquoNeil ldquoCompilation of stable isotopefractionation factors of geochemical interestrdquo in Data of

Journal of Chemistry 13

Geochemistry Geological Survey Professional Paper 440-KKchapter KK 1977

[7] A Silvestri and A Marcante ldquoThe glass of Nogara (Verona) aldquowindowrdquo on production technology of mid-Medieval times inNorthern Italyrdquo Journal of Archaeological Science vol 38 no 10pp 2509ndash2522 2011

[8] S Alberta M Gianmario and P Valentina ldquoThe stained glasswindow of the southern transept of St Anthonyrsquos Basilica(Padova Italy) study of glasses and grisaille paint layersrdquoSpectrochimica ActamdashPart B Atomic Spectroscopy vol 66 no1 pp 81ndash87 2011

[9] K Govindaraju ldquoCompilation of working values and sampledescription for 383 geostandardsrdquoGeostandards Newsletter vol18 pp 1ndash158 1994

[10] A Savitzky andM J EGolay ldquoSmoothing anddifferentiation ofdata by simplified least squares proceduresrdquo Analytical Chem-istry vol 36 no 8 pp 1627ndash1639 1964

[11] J Henderson J A Evans H J Sloane M J Leng and CDoherty ldquoThe use of oxygen strontium and lead isotopesto provenance ancient glasses in the Middle Eastrdquo Journal ofArchaeological Science vol 32 no 5 pp 665ndash673 2005

[12] K A Leslie I C Freestone D Lowry and M Thirlwall ldquoTheprovenance and technology of Near Eastern glass oxygenisotopes by laser fluorination as a complement to strontiumrdquoArchaeometry vol 48 no 2 pp 253ndash270 2006

[13] R H Brill ldquoScientific investigations of the Jalame glass andrelated findsrdquo in Excavations at Jalame Site of a Glass Factory inLate Roman Palestine G D Wienberg Ed pp 257ndash293University of Missouri Press Columbia Mo USA 1988

[14] M Pomerancblum ldquoThe distribution of heavy minerals andtheir hydraulic equivalents in sediments of the Mediterraneancontinental shelf of Israelrdquo SEPM Journal of SedimentaryResearch vol 36 pp 162ndash174 1966

[15] D J Stanley Y Mart and Y Nir ldquoClay mineral distributions tointerpret Nile cell provenance and dispersal II Coastal plainfrom Nile delta to northern Israelrdquo Journal of Coastal Researchvol 13 no 2 pp 506ndash533 1997

[16] M B Hatzopoulos and L D Loukopoulou Morrylos Centrede Recherches de lrsquoAntiquite Grecque et Romaine AthenesGreece 1989

[17] E Dotsika D Poutoukis I Tzavidopoulos Y Maniatis DIgnatiadou and B Raco ldquoA natron source at Pikrolimni Lake inGreece Geochemical evidencerdquo Journal of Geochemical Explo-ration vol 103 no 2-3 pp 133ndash143 2009

[18] H E Foster and C M Jackson ldquoThe composition of ldquonaturallycolouredrdquo late Roman vessel glass from Britain and the impli-cations for models of glass production and supplyrdquo Journal ofArchaeological Science vol 36 no 2 pp 189ndash204 2009

[19] I C Freestone ldquoAppendix chemical analysis of lsquorawrsquo glass frag-mentsrdquo in Excavations at Carthage Volume II1 The CircularHarbour North SideThe Site and FindsOther than Pottery H RHurst Ed British Academy Monographs in Archaeology N∘4p 290 Oxford University Press Oxford UK 1994

[20] I C Freestone M Ponting and M J Hughes ldquoThe origins ofByzantine glass from Maroni Petrera Cyprusrdquo Archaeometryvol 44 no 2 pp 257ndash272 2002

[21] D C W Sanderson J R Hunter and S E Warren ldquoEnergydispersive X-ray fluorescence analysis of 1stmillennium ad glassfrom Britainrdquo Journal of Archaeological Science vol 11 no 1 pp53ndash69 1984

[22] D Foy M Picon M Vichy and V Thirion-Merle ldquoCar-acterisation des verres de la fin de lrsquoAntiquite en Mediterraneeoccidentale lrsquoemergence de nouveaux courants commerciauxrdquoin Echanges et Commerce du Verre dans le Monde Antique DFoy and M D Nenna Eds Actes du Colloque de lrsquoAssociationFrancaise pour lrsquoArcheologie du Verre Aix-en-Provence etMarseille June 2001 pp 41ndash85 Monique Mergoil MontagnacFrance 2003

[23] D Rosenow and T Rehren ldquoHerding cats Roman to LateAntique glass groups from Bubastis northern Egyptrdquo Journal ofArchaeological Science vol 49 no 1 pp 170ndash184 2014

[24] P Mirti A Casoli and L Appolonia ldquoScientific analysis ofroman glass from augusta praetoriardquo Archaeometry vol 35 no2 pp 225ndash240 1993

[25] A Silvestri G Molin and G Salviulo ldquoRoman and medievalglass from the Italian area bulk characterization and relation-ships with production technologiesrdquo Archaeometry vol 47 no4 pp 797ndash816 2005

[26] A Silvestri S Tonietto and G Molin ldquoThe palaeo-Christianglass mosaic of St Prosdocimus (Padova Italy) archaeometriccharacterisation of lsquogoldrsquo tesseraerdquo Journal of ArchaeologicalScience vol 38 no 12 pp 3402ndash3414 2011

[27] F Gallo and A Silvestri ldquoMedieval glass from Rocca di Asolo(northern italy) an archaeometric studyrdquoArchaeometry vol 54no 6 pp 1023ndash1039 2012

[28] F Gallo A Marcante A Silvestri and G Molin ldquoThe glass ofthe ldquoCasa delle Bestie Feriterdquo a first systematic archaeometricstudy on Late Roman vessels from Aquileiardquo Journal of Archae-ological Science vol 41 pp 7ndash20 2014

[29] S Maltoni T Chinni M Vandini E Cirelli A Silvestri andG Molin ldquoArchaeological and archaeometric study of the glassfinds from the ancient harbour of Classe (Ravenna-Italy) newevidencerdquo Heritage Science vol 3 no 1 article 13 2015

[30] A Ceglia P Cosyns K Nys H Terryn H Thienpont and WMeulebroeck ldquoLate antique glass distribution and consumptionin Cyprus a chemical studyrdquo Journal of Archaeological Sciencevol 61 pp 213ndash222 2015

[31] N Schibille A Sterrett-Krause and I C Freestone ldquoGlassgroups glass supply and recycling in late Roman CarthagerdquoArchaeological and Anthropological Sciences pp 1ndash19 2016

[32] A Cholakova T Rehren and I C Freestone ldquoCompositionalidentification of 6th c AD glass from the Lower DanuberdquoJournal of Archaeological Science Reports vol 7 pp 625ndash6322016

[33] S Conte T Chinni R Arletti and M Vandini ldquoButrint(Albania) between eastern and western Mediterranean glassproduction EMPA and LA-ICP-MS of late antique and earlymedieval findsrdquo Journal of Archaeological Science vol 49 no1 pp 6ndash20 2014

[34] I C Freestone S Wolf and M Thirlwall ldquoThe production ofHIMT glass elemental and isotopic evidencerdquo inAnnales du 16eCongres de lrsquoAssociation Internationale pour lrsquoHistoire du Verre(AIHV rsquo05) pp 153ndash157 London UK 2005

[35] M D Nenna M Picon and M Vichy ldquoAteliers primaries etsecondaries en Egypte a lrsquoepoque greco-romainerdquo in La Routedu Verre Ateliers Primaires et Secondaires du Second Millenaireav J-C au Moyen Age M D Nenna Ed vol 33 pp 97ndash112Travaux de la Maison de lrsquoOrient Mediterraneen 2000

[36] C M Jackson ldquoMaking colourless glass in the Roman periodrdquoArchaeometry vol 47 no 4 pp 763ndash780 2005

[37] E V Sayre ldquoThe intentional use of antimony and manganese inancient glassesrdquo in Advances in Glass Technology Part 2 F R

14 Journal of Chemistry

Matson and G Rindone Eds pp 263ndash282 Plenum Press NewYork NY USA 1963

[38] H E Foster and C M Jackson ldquoThe composition of lateRomano-British colourless vessel glass glass production andconsumptionrdquo Journal of Archaeological Science vol 37 no 12pp 3068ndash3080 2010

[39] J Henderson ldquoThe raw materials of early glass productionrdquoOxford Journal of Archaeology vol 4 no 3 pp 267ndash291 1985

[40] B Gratuze and K Janssens ldquoProvenance analysis of glassartefactsrdquo inNon-Destructive Microanalysis of Cultural HeritageMaterials K Janssens and R Van Grieken Eds pp 663ndash712Elsevier Amsterdam The Netherlands 2004

[41] J Henderson ldquoTradition and experiment in first millenniumAD glass productionmdashthe emergence of early Islamic glasstechnology in late antiquityrdquoAccounts of Chemical Research vol35 no 8 pp 594ndash602 2002

[42] P Mirti M Pace M M Negro Ponzi and M Aceto ldquoICP-MSanalysis of glass fragments of Parthian and Sasanian epoch fromSeleucia and Veh Ardasır (Central Iraq)rdquoArchaeometry vol 50no 3 pp 429ndash450 2008

[43] P Mirti M Pace M Malandrino and M N Ponzi ldquoSasanianglass from Veh Ardasır new evidences by ICP-MS analysisrdquoJournal of Archaeological Science vol 36 no 4 pp 1061ndash10692009

[44] J Hoefs Stable Isotope Geochemistry Springer Berlin Ger-many 5th edition 2004

[45] A Silvestri G Molin and G Salviulo ldquoThe colourless glass ofIulia Felixrdquo Journal of Archaeological Science vol 35 no 2 pp331ndash341 2008

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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CatalystsJournal of

Journal of Chemistry 3

Table 1 List of analysed glasses from Greece Colour age and provenance also shown

Sample Colour Age ProvenanceNumber Century AD1-1 Light green 1stndash6th Agora-Thessaloniki2-1 Green blue 1stndash6th Agora-Thessaloniki3-1 Colourless 1stndash6th Agora-Thessaloniki4-1 Blue 1stndash6th Agora-Thessaloniki5-1 Light green 1stndash6th Agora-Thessaloniki6-1 Colourless 1stndash6th Agora-Thessaloniki7-1 Greenbrown 1stndash6th Agora-Thessaloniki8-1 Light green 1stndash6th Agora-Thessaloniki9-1 Light blue 1stndash6th Agora-Thessaloniki10-1 Colourless 1stndash6th Agora-Thessaloniki1-2 Light green 4thndash6th Maroneia church2-2 Green 4thndash6th Maroneia church3-2 Light yellow 4thndash6th Maroneia church4-2 Green-blue 4thndash6th Maroneia church5-2 Light green 4thndash6th Maroneia church6-2 Colourless 4thndash6th Maroneia church7-2 Light yellow 4thndash6th Maroneia church8-2 Very light brown 4thndash6th Maroneia church9-2 Light blue 4thndash6th Maroneia church10-2 Very light green 4thndash6th Maroneia church1-3 Light green 1thndash6th Agora cryptoporticus-Thessaloniki2-3 Colourless 1thndash6th Agora cryptoporticus-Thessaloniki3-3 Light green 3th-4th West cemetery tomb-Thessaloniki4-3 Green 1thndash6th School of religion-Thessaloniki5-3 Greenish 1thndash6th School of religion-Thessaloniki6-3 Colourless 6th Administration building-Thessaloniki7-3 Light yellow 1thndash6th Administration building-Thessaloniki3-4 Light green 5th-6th landscape of Nastos-Thessaloniki4-4 Greenish 1stndash6th Socratous street-Thessaloniki5-4 Greenish 1stndash6th Socratous street-Thessaloniki6-4 Greenish 1stndash6th Socratous street-Thessaloniki7-4 Aquamarine 1stndash6th Socratous street-Thessaloniki8-4 Green 1stndash6th Thessaloniki9-4 Colourless 1stndash6th Thessaloniki10-4 Blue 1stndash6th Thessaloniki11-4 Green 1stndash6th Thessaloniki12-4 Brown 1stndash6th Thessaloniki13-4 Greenish 1stndash6th Thessaloniki14-4 Green 1stndash6th Thessaloniki

albite for Na diopside for Si and Ca apatite for P sphaleritefor Zn and S vanadinite for Cl orthoclase for K Sb2S for SbPbS for Pb and pure elements for Co Ni and Cu Operatingconditions were 20 kV and 2 nA sample current with beamdefocused at not less than 10 120583m forNa K Si and Al in orderto minimise the loss of alkali elements and better evaluate Sicontents and at 20 kV and 30 nA for other elements X-raycounts were converted to oxide weight percentages with thePAP (CAMECA) correction programThe detailed analytical

conditions used and the precision accuracy and detectionlimits of EMPA are given in Silvestri and Marcante [7] asthe present samples were subjected to the same analyticalprotocol It is stressed here that the precision and accuracyof data were calculated by comparisons with measures onthe international reference standard Corning glass B inthe same analytical conditions as our Greek samples Theprecision of EMPA data was generally between 05 and10 for major and minor elements respectively Accuracy

4 Journal of Chemistry

Table 2 Isotopic and chemical composition of Roman and late Antique glasses from Thessaloniki Agora 1stndash6th century AD in age Notethat CoO and NiO contents are not reported because they are lower than EMPA detection limits for all samples (LOD of CoO and NiO =003wt)

Sample 12057518O SiO2 Na2O CaO Al2O3 K2O MgO FeO TiO2 MnO P2O5 SO3 Cl CuO ZnO SnO2 Sb2O3 PbONumber (VSMOW) Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt1-1 155 6617 1690 860 268 065 146 122 018 164 013 035 068 lt003 lt004 lt004 lt004 lt0082-1 156 6465 1496 614 316 094 149 111 020 148 065 016 065 067 004 089 lt004 2903-1 155 7148 1540 742 244 037 059 058 009 055 002 024 096 lt003 lt004 lt004 lt004 lt0084-1 156 6424 988 574 159 1147 348 030 003 lt005 130 007 064 lt003 lt004 lt004 009 lt0085-1 154 6768 1694 708 273 057 096 159 028 109 007 023 109 lt003 lt004 lt004 lt004 lt0086-1 155 7298 1700 498 209 056 051 029 009 lt005 001 022 090 lt003 lt004 lt004 025 lt0087-1 156 6543 1976 654 238 040 108 114 026 112 002 027 160 014 lt004 lt004 lt004 0338-1 155 6714 1683 786 292 091 129 165 020 145 026 025 054 lt003 lt004 lt004 lt004 lt0089-1 156 6553 1733 784 295 085 141 139 019 167 026 030 053 lt003 lt004 lt004 lt004 lt00810-1 155 7651 967 811 025 378 103 006 lt004 lt005 006 040 019 lt003 lt004 lt004 lt004 lt008

155 plusmn 007permilmean isotopic composition

was better than 1 for SiO2 Na2O and FeO better than 5for CaO K2O P2O5 and Sb2O3 and not worse than 12 forother major and minor elements

The chemical and mineralogical compositions of chertsamples were obtained bymeans of X-ray fluorescence (XRF)and X-ray powder diffraction (XRPD) respectively

X-ray fluorescence (XRF) was carried out on a PhilipsPW 2400 instrument equipped with a Rh tube with a ratedcapacity of 3 kW (60 kV125mA max) Three primary col-limators (150 300 and 700120583m spacing) and four analyticalcrystals (TlAp100 LiF200 Ge111 and PE002) were selectedThe spectrometer was interfaced with a personal computerwith SuperQ software (Philips) Instrumental parametersand analytical conditions are detailed in Alberta et al [8]Geological reference standards were used for calibration [9]Precision was better than 06 for major andminor elementsand about 3 for trace elements XRF accuracy was checkedby reference standards [9] and was within 05 wt for Silower than 3 for othermajor andminor elements and lowerthan 5 for traces The lowest detection limits of XRF werewithin 002wt for Al2O3 MgO and Na2O within 04 wtfor SiO2 and within 0005wt for TiO2 Fe2O3 MnO CaOK2O and P2O5 and range from 3 to 10 ppm for trace elementsFor this type of analysis chert fragments were crushed in anagatemortarThe resulting powders were heated in an oven at860∘C for 20min and then at 980∘C for 2 hours and the losson ignition (LOI) was determined The powders were thenmixed with Li2B4O7 at a 1 10 ratio and beads were prepared

XRPD data were obtained on a computer-controlledPhilips XrsquoPert PRO with Bragg-Brentano 120579-120579 geometry Thenormal-focus CuX-ray tube (CuK1205721 120582= 0154056 nm) oper-ated at 40KV and 20mA Data were recorded in the 2∘ndash70∘2120579 range in step-scan mode with step width increments of002∘ and a step counting time of 10 s Data were processedby the XrsquoPert HighScore (PANalytical copyright) 2120579 and 119889values were calculated with the second-derivative algorithmof Savitzky andGolay [10] All XRPDdiffraction profiles werecarried out on about 500mg of samples finely ground into anagate mortar

It should be stressed here that XRPD analyses werecarried out on all the chert samples while XRF analyseswere carried out only on samples Trd 1-2 and Trd 1-5 whichare representative of the two mineralogical compositionsidentified

3 Results and Discussion

31 Results The ten samples from the Thessaloniki Agorashow an extremely homogeneous oxygen isotopic composi-tion (154ndash156permil Table 2) All the samples from the churchof Maroneia 4thndash6th centuries AD in age also have isotopiccompositions ranging from 152 to 160permil with mean valueequal to 156plusmn025permil(Table 3)Theirmean isotopic values arepractically identical to those of the first set of samples fromThessaloniki although the range of values from Maroneia isslightly largerThe isotopic results obtained on the remainingnineteen glasses from Thessaloniki indicate that only ninesamples (4-3 5-3 7-3 4-4 5-4 6-4 7-4 11-4 and 14-4)have values very close to those measured in samples fromThessaloniki Agora and Maroneia (Table 4)

In contrast with the remarkable isotopic homogeneity ofthemajority ofGreek glass samples (2939 samples) chemicalcompositions are rather heterogeneous (Tables 2 3 and 4)In particular samples 1-1 5-1 8-1 9-1 (Table 2) 4-3 6-4 11-4 and 14-4 (Table 4) from Thessaloniki and all the samplesfrom Maroneia (Table 3) show SiO2 contents ranging from6448 to 6768wt Na2O from 1636 to 1846wt CaOfrom 702 to 907wt and Al2O3 from 229 to 292wtK2O and MgO contents are both lower than 15 wt in allthe considered samples although MgO is higher than K2O(MgO = 125 plusmn 015wt versus K2O = 070 plusmn 013wt)Thisgroup of samples also shows the highest iron titanium andmanganese contents (FeO from 080 to 212 wt TiO2 from014 to 037wt and MnO from 096 to 265wt) andnondetectable trace elements

The other glass samples from Thessaloniki (2-1 3-1 6-17-1 5-3 7-3 4-4 5-4 and 7-4) whose 12057518O is in the range153ndash156permil (Tables 2 and 4) also show comparable SiO2

Journal of Chemistry 5

Table 3 Isotopic and chemical composition of glasses fromMaroneia 4thndash6th centuries AD in age Note that CoO NiO CuO ZnO SnO2Sb2O3 and PbO contents are not reported because they are lower than EMPA detection limits for all samples (LOD of CoO NiO and CuO =003 wt LOD of ZnO SnO2 Sb2O3 = 004 wt LOD of PbO = 008 wt)

Sample 12057518O SiO2 Na2O CaO Al2O3 K2O MgO FeO TiO2 MnO P2O5 SO3 ClNumber (VSMOW) Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt1-2 154 6711 1739 784 229 061 110 106 015 154 007 030 1022-2 155 6623 1780 783 270 076 123 133 017 123 015 031 0923-2 156 6462 1770 898 240 072 147 104 016 182 012 034 0924-2 159 6564 1846 795 270 082 121 138 016 096 013 032 0915-2 156 6570 1738 825 238 059 121 088 015 169 009 034 0956-2 156 6679 1717 750 253 060 125 098 016 184 008 030 1007-2 157 6463 1796 907 257 071 150 110 018 172 013 033 0928-2 152 6556 1756 752 250 065 125 093 017 234 009 029 1019-2 160 6613 1814 783 273 084 122 128 015 099 016 034 09010-2 153 6659 1636 859 240 069 111 088 017 160 011 036 087

156 plusmn 02permilmean isotopic composition

Table 4 Isotopic and chemical composition of Roman and late Antique glasses from Thessaloniki 1stndash6th centuries AD in age Sampleswith moderate and strong 18O enrichment are in italics and bold font respectively Note that NiO ZnO and SnO2 contents are not reportedbecause they are lower than EMPA detection limits for all samples (LOD of NiO = 003wt LOD of ZnO and SnO2 = 004wt)

Sample 12057518O SiO2 Na2O CaO Al2O3 K2O MgO FeO TiO2 MnO P2O5 SO3 Cl CoO CuO Sb2O3 PbONumber (VSMOW) Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt1-3 226 6746 1300 974 117 485 201 058 006 096 069 007 128 lt003 lt003 lt004 lt0082-3 225 6731 1320 980 115 477 200 057 005 096 066 007 129 lt003 lt003 lt004 lt0083-3 186 6695 1946 671 221 043 096 063 010 127 010 025 143 lt003 lt003 lt004 lt0084-3 158 6420 1767 702 285 040 128 212 037 265 010 040 123 lt003 lt003 lt004 lt0085-3 156 6789 1617 864 268 053 083 044 007 136 007 035 119 lt003 lt003 lt004 lt0086-3 173 6492 1919 821 232 059 106 094 014 158 007 045 087 lt003 lt003 lt004 lt0087-3 152 7162 1553 647 263 065 042 026 004 033 009 003 106 lt003 lt003 lt004 lt0083-4 161 6478 1862 775 237 059 119 115 015 152 005 044 093 lt003 lt003 lt004 lt0084-4 153 6732 1696 785 252 031 088 072 022 161 001 028 136 lt003 lt003 lt004 lt0085-4 153 6678 1796 652 240 050 095 079 021 166 002 029 119 lt003 lt003 lt004 lt0086-4 153 6525 1746 783 246 062 100 080 015 192 005 047 099 lt003 lt003 004 lt0087-4 153 6580 1876 630 189 054 087 067 010 077 004 031 146 lt003 178 lt004 lt0088-4 156 6156 1248 1003 390 495 193 079 017 073 043 014 088 lt003 lt003 004 0509-4 227 6780 980 921 110 545 235 051 005 067 052 010 091 lt003 lt003 004 lt00810-4 164 6546 1983 636 248 049 116 117 016 011 001 052 123 004 021 lt004 06311-4 154 6451 1791 864 265 076 118 143 014 066 011 045 098 lt003 lt003 lt004 lt00812-4 205 6272 1179 945 134 440 204 092 006 438 039 013 105 lt003 lt003 006 lt00813-4 173 6444 1268 964 234 423 207 076 012 121 042 016 101 lt003 lt003 004 01414-4 156 6448 1781 723 258 079 134 197 015 115 014 054 098 lt003 lt003 lt004 lt008

Na2O CaO K2O and MgO contents with the previousglass samples although they differ in contents of colour-ingdecolouring elements for example iron copper man-ganese and antimony and minor elements for example tinand lead (Tables 2 and 4) In particular samples 5-3 4-4 and5-4 show concentrations of manganese higher than 1 wtwhereas sample 6-1 has nomanganese but antimony (Table 2)Instead samples 3-1 and 7-3 do not reveal any manganeseor antimony (Tables 2 and 4) Sample 2-1 from ThessalonikiAgora has relatively high concentrations of CuO SnO2 PbO

and P2O5 (Table 2) The chemical composition of sample7-1 is comparable with that of sample 2-1 except for thelower copper and lead contents (Table 2) Lastly samples 4-1 and 10-1 from Thessaloniki Agora which have comparable12057518Ovalues show chemical compositions different from eachother except for the similar (and relatively low) content ofsodium (about 10 wt Na2O) and the absence of manganeseand trace elements in both samples In particular sample 4-1has lower SiO2 and CaO and higher Al2O3 K2O MgO FeOP2O5 and Cl than sample 10-1 (Table 2)

6 Journal of Chemistry

Table 5 12057518O(VSMOW) of chert samples from the quarries in Triadiof Thessaloniki (Central Macedonia Greece)

Samples 12057518O(VSMOW) MeanTrd 1-1 250 251 250Trd 1-2 234 235 234Trd 1-4 236 238 237Trd 1-5 260 261 260Trd 2-1 242 244 243Trd 3-1 261 260 260Trd 3-2 258 260 259Trd 5-2 225 223 224

Mean value 246 plusmn 14permil

Lastly sample 8-4 fromThessaloniki with 12057518O equal to156permil is characterised by lower silicium and sodium con-tents and higher calcium aluminium potassium magne-sium and phosphorous contents (Table 4) than other glasseswith comparable isotopic composition

In addition to samples with isotopic signatures rangingfrom 152 to 160permil the isotopic data indicate that foursamples fromThessaloniki are heavily enriched by about 7permilsample 12-4 has 12057518O equal to 205permil and samples 1-3 2-3and 9-4 have values from 225 to 227permil Finally other fivesamples fromThessaloniki (3-3 6-3 3-4 10-4 and 13-4) showmoderate 18O enrichment with values between 161 and186permil (Table 4)

The chemical analyses of the heavily enriched glass(Table 4) show that all samples are characterised by higherCaO K2O MgO and P2O5 and lower Na2O and Al2O3contents than other Greek samples with lower isotopic com-position In addition sample 12-4 also has exceptionally highmanganese (MnO = 438wt Table 4)

The samples with moderate 18O enrichment show quitevariable chemical compositions but comparable to those ofsamples with lower and higher isotopic compositions Sam-ples 3-3 (12057518O= 186permil) and 10-4 (12057518O= 164permil) have chem-ical compositions comparable to those of samples 5-3 4-4and 5-4 although sample 10-4 has very little Mn and highCu and Pb (Table 4) Sample 6-3 (12057518O = 173permil) is similarin chemical composition to samples 1-1 5-1 8-1 91 4-3 6-4 11-4 and 14-4 from Thessaloniki (Tables 2 and 4) and allthe samples from Maroneia (Table 3) Finally the chemicalcomposition of sample 13-4 (12057518O = 173permil) is very similar tothose of the heavily enriched glass as deduced from itslow Na2O and Al2O3 and high CaO K2O MgO and P2O5contents (Table 4)

The isotopic data obtained on the chert samples from thequarries in Triadi ofThessaloniki show that mean 12057518O value(equal to 246 plusmn 14permil Table 5) is comparable to those ofGreek glass samples heavily enriched (mean 12057518O value =221 plusmn 11permil) Mineralogical data obtained by means ofXRPD show chert samples are a mixture of quartz andgoethite (semiquantitative contents of the two phases 94quartz and 6 goethite) except for sample Trd 1-5 composedof only quartz (Figure 1)

XRF data furtherly confirm the mineralogical composi-tions sample Trd 1-2 being almost entirely composed of SiO2and Fe2O3 and Trd 1-5 of only SiO2 (Table 6)

32 Discussion The majority of the analysed samples fromThessaloniki and all the samples from Maroneia have ahomogeneous oxygen isotopic composition (12057518O value =156 plusmn 025permil Table 2 and Figure 2) which is equal orvery close to the mean value of ldquoRomanrdquo glass as deducedfrom a set of isotopic measurements on glass from Europedated from the 1st to the 4th centuries AD which show arelatively narrow range of 12057518O (from about 154permil to 160permil)[2 3] Similar results (Figure 2) were also obtained for lateAntiqueearly Medieval samples from Grado and Vicenzatwo sites in Northern Italy [3] and for coeval glass from theNear East [11 12]

These similarities may be explained by assuming thatthe Greek glass samples were produced with raw materialswith equal or very similar oxygen isotopic compositionSand from the rivers Belus in Palestine and Volturno inItaly mentioned by Pliny the Elder in Naturalis Historia asmaterials for making glass is suitable for glass productionand has the same oxygen isotopic composition when theVolturno sandundergoes selective grinding [3] It follows thatglass produced with either Belus or Volturno sand as networkformer and natron as flux is practically indistinguishablefrom the oxygen isotopic point of view Consequently theisotopic composition of most of the Greek samples in Tables2 3 and 4 cannot help to distinguish among glass samplesimported from Italy or the Near East or glass samplesproduced inGreek secondary glassworkshops bymelting rawglass from the geographic point of view a Levantine originfor the Greek glass samples is quite reasonable This origin isreinforced by data reported in Brill [13] on five cullets froman ancient glass workshop at Jalame in western Galilee (3rd-4th centuries AD) The author suggests that the silica usedfor these cullets came from sand taken from the mouth ofthe Belus and that the oxygen isotopic composition of quartzwas enriched in 18O by the calcium carbonate contained inthe sand in the form of sea shells with natron as flux The12057518O values of the Jalame glass are slightly lower than thoseof Greek samples and range from about 14 to 15permil (Figure 2)Although the use of various other raw materials cannot becompletely excluded this small difference may be explainedby amounts of natron used for melting which are slightlysmaller in Jalame than in Greek glass samples The oxygenisotopic study carried out by Silvestri et al [3] on Romannatron glass demonstrated the ldquopositive natron effectrdquo that isit is presumed that flux which has very positive 12057518O valuescaused 18O enrichment in the final glass as confirmed bythe plot of Na2O versus 12057518O which clearly shows a positivecorrelation Other glass samples from the Near East have12057518O values close to those of our samples showing ldquoRomanrdquovalues (Figure 2) These samples measured by Leslie et al[12] came from different locations three from the BethShersquoan in Israel (6th-7th centuries AD) mean value 146permilthree from Tel el-Ashmunein in Egypt (8th-9th centuries)mean value 148permil and three from Carthage in Tunisia

Journal of Chemistry 7

10 20 30 40 50 60 70

Cou

nts

0

TRD-1-2

Peak list

Goethite syn FeO(OH)

50000

100000

150000

Quartz low SiO2

Position (∘2휃) (copper (Cu))

(a)

TRD-1-5

10 20 30 40 50 60 70

Cou

nts

Peak list

0

100000

200000

Quartz low SiO2

Position (∘2휃) (copper (Cu))

(b)

Figure 1 XRPD patterns of chert samples named Trd 1-2 (a) and Trd 1-5 (b) representative of the twomineralogical compositions identified

(4thndash6th centuries) mean value 150permil All these samplesare obtained using natron from the evaporitic lakes of WadiNatron in Egypt The provenance of sand from a relativelyshort stretch of the eastern Mediterranean coast is suggestedfor the Beth Shersquoan samples and the similarity between thedelta values of the Tel el-Ashmunein and Carthage samplesis explained by their production with the same Egyptiansand The isotopic similarity among these three groups ofsamples can be explained taking into account a commonprovenance for natron and that Levantine sand comes fromEgypt and is transported up to the eastern Mediterraneancoast by sea currents [14 15] therefore the use of sandand flux with similar provenance yields glass samples withsimilar isotopic compositions The same source may thusbe hypothesised for the Greek glass samples analysed hereHowever it should be stressed that natural natron depositsin the region of Macedonia in northern Greece were well-known in the time of Plato (5th century BC) and werealso described by Pliny the Elder in his Naturalis HistoriaeHatzopoulos and Loukopoulou [16] identified Lake Chalastra(so-called in antiquity that is the place where the ldquoCha-lastraion nitronrdquo formed and dissolved over a period of afew days) as the modern lake of Picrolimni located about20 km NW of Thessaloniki The geochemical conditionsresponsible for the formation of ldquoChalastraion nitronrdquo haverecently been studied and discussed by Dotsika et al [17]The salts deposited by the lake brine were mineralogicallyidentified by XRD analysis and include not only calcite anddolomite but also trona (Na2CO3sdotNaHCO3sdot2H2O) burkeite(Na2CO3sdot2Na2SO4) and halite (NaCl) thus confirming themineralogical similarity between these deposits and thosefrom Wadi Natron in Egypt However the oxygen isotopiccompositions determined on the Picrolimni salt deposits

range from about 11 to 25permil (VSMOW) much lower than thevalues for Wadi Natron (about 34 to 40permil [2 3]) Thereforein the case of our samples use of ldquoChalastraion nitronrdquo as fluxcan hardly be considered

In contrast with the remarkable isotopic homogeneity ofthe majority of Greek samples (2939 samples) the chemicalcomposition is rather heterogeneous (Tables 2 3 and 4)although they are all obtainedwith natron as flux having bothK2O and MgO contents lower than 15 wt In particularsamples 1-1 5-1 8-1 9-1 4-3 6-4 11-4 and 14-4 fromThessaloniki (Tables 2 and 4) and all the samples fromMaroneia (Table 3) show the HIMT (High Iron Magnesiumand Titanium) signature This reference group is defined byhigh levels of iron (ge07 wt)manganese (usually sim1-2 wt)magnesium (usuallyge08 wt) and titanium (ge01 wt) andits yellow-green colour is due to the amount of iron sugges-tive of a relatively impure sand source [18] These also are thekey characteristics of Greek glass samples which have highFeO (120 plusmn 031wt) MnO (154 plusmn 035wt) MgO (124 plusmn016wt) and TiO2 (018plusmn005wt) contentsThe acronymHIMT was first applied by Freestone [19] to raw glass fromCarthage and glass vessels from Cyprus [20] although glasswith high contents of iron manganese and titanium wasalready identified by Sanderson et al [21] However all theGreek samples (except 4-3) containing about 50ndash60 of theamount of iron titanium and manganese oxides measuredin ldquotypicalrdquo HIMT glass such as Group 1 of Foy et al [22](about 121 plusmn 031wt as FeO 017 plusmn 003wt as TiO2and 151 plusmn 037wt as MnO versus 2 plusmn 08wt as FeO05 plusmn 01wt as TiO2 and 22 plusmn 04wt as MnO for Greeksamples and Group 1 resp) show a better fit with ldquoGroup 2rdquoof Foy et al [22] whichmay be considered as a ldquoweakrdquo HIMTglass [18] due to lower contents of the key oxides of HIMT

8 Journal of Chemistry

Table6Ch

emicalcompo

sitions

ofchertsam

plesn

amed

Trd1-2

andTrd1-5

representativeof

thetwomineralogicalcompo

sitions

identifi

ed(X

RFdataL

OIlosson

ignitio

n)N

otethat

GaYNbLaC

eandUcontentsaren

otrepo

rted

becausetheyarelow

erthan

XRFdetectionlim

itsfora

llsamples

(LODof

Ga=

5ppm

LODof

YNbandU=3p

pmLODof

LaandCe=

10pp

m)

Sample

SiO2

TiO2

Al 2O3

Fe2O3

MnO

MgO

CaO

Na 2O

K 2O

P 2O5

LOI

ScV

CrCo

Ni

CuZn

RbSr

ZrBa

Nd

PbTh

Num

berWt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

Trd1-2

9068

001

021

713

015

037

012

005

001

002

218

9314

507

124

146

1846

78

920

1912

7Trd1-5

9998lt00

05lt00

2lt00

05lt00

05lt00

2lt00

05lt00

2lt00

05lt00

05000lt3lt3lt3lt3lt3lt3lt3lt3lt3lt3lt10lt10lt10lt3

Journal of Chemistry 9

10 11 42 10 9 5 9 16 414

15

16

17

18

19

Number of samples

훿18O

(VSM

OW

)(permil

)

Figure 2 Comparisons among 12057518O(VSMOW) values of natron glasssamples [open symbols Thessaloniki Agora (◻) Maroneia ()Thessaloniki various sites (998779)Thessaloniki glass withmoderate 18Oenrichment (I)] and those already reported in the literature [fullsymbols Roman glass from Europe (◼) [2] Roman glass from IuliaFelix (X) [3] 4th century AD glass from Jalame (998771) [2] HIMTglass from Carthage and Levantine natron glass (bold plus sign)[12] late Antique-earlyMedieval glass fromGrado ad Vicenza (boldmultiplication sign) [3]] Number of analysed samples is also shown

glass (Figure 3) Instead sample 4-3 has FeO TiO2 andMnO contents (Table 4) perfectly comparable with ldquotypicalrdquoHIMT glass [18 22] In general HIMT glass has also beenidentified in Britain [18] Egypt [23] France [22] Italy [24ndash29] Cyprus [20 30] Carthage [31] Bulgaria [32] andAlbania[33] The chemical and isotopic signatures of HIMT glass aresuggestive of continental sand sources of high maturity richin heavy minerals and located in the Near East probablyin Egypt [12 31 34] As regards the dating of the referencegroups in general terms the HIMT group is probably morecharacteristic of the period from the mid-4th century ADonwards although according to current research its compo-sition seems to have continued after the 5th century [18]In addition according to Schibille et al [31] ldquoGroup 2rdquo isdated to the 5th-6th centuries and is thus coeval with theglass from Maroneia Consequently the age of Thessalonikiglass samples similar in composition to those of ldquoGroup 2rdquois constrained to the late Antique period

The other glass samples from Thessaloniki (2-1 3-1 6-17-1 5-3 7-3 4-4 5-4 and 7-4) whose 12057518O is in therange of ldquoRomanrdquo values also show the chemical compo-sition typical of Roman glass [35] although they differ incontents of manganese and antimony (Figure 3) and traceelements In particular samples 3-1 5-3 4-4 and 5-4 showMnO gt 05 wt which suggests its intentional addition asa decolouriser [36] whereas sample 6-1 has no manganesebut antimony (Table 2) As these two elements the principal

decolourisers used between the 1st and 4th centuries ADwere both predominant from the late 1st to the 3rd centuriesand as the use of manganese increased from the end of the3rd to the 4th century [36ndash38] the age of these samples isconstrained accordingly Instead samples 3-1 and 7-3 do notreveal any intentional addition of decolouriser having noantimony and MnO lt 05 wt (Tables 2 and 4) Sample 2-1from Thessaloniki Agora has relatively high concentrationsof CuO SnO2 PbO and P2O5 (Table 2) suggesting theinclusion of cullet perhaps coloured and opaque mosaictesserae containing high quantities of one or more of theseelements in the glass batch The chemical composition ofsample 7-1 is not far from that of sample 2-1 although the con-centrations of copper and lead are much lower than those insample 2-1 (Table 2) This indicates that the presence ofthe above elements is due to recycling of earlier colouredglass because they occur in concentrations higher than thoseattributable to impurities in the raw materials but too low tohave any technological significance [39] Conversely the highCu in sample 7-4 not associated with high Sn Co Pb Sband Zn (Table 4) suggests that this element was intentionallyadded to produce the aquamarine colour

Lastly chemical similarities between samples 4-1 and 10-1from Thessaloniki Agora and data reported in the literatureare difficult to establish Sample 4-1 seems quite comparablewith some soda-potash-lime glass from the 14th-centuryworkshop at Saint-Chely (France) Two different hypothesesboth equally valid from an analytical point of view are pro-posed to explain the peculiar chemical composition of theseLate Medieval French samples [40] both soda and potashash were used by the glass-workers soda ash remaining themain component recycled glass from the surrounding areaswith both potash and soda ash compositions was used asrawmaterials Sample 10-1 also approaches although not per-fectly the composition of ldquomixed soda-potash glassrdquo dated toLate Bronze age [40] and the oxygen isotopic data obtained byBrill et al [2] on some Late Bronze age objects are also quitecomparable with that of sample 10-1 On the contrary oxygenisotope data on samples with chemical composition similarto sample 4-1 are unfortunately still lacking although dataon Medieval soda ash and late Medieval and modern potashash glass are systematically lower and range from about 12to 145permil [2 3] In any case both isotopic and chemical datasuggest that the age proposed for samples 4-1 and 10-1 fromThessaloniki Agora should be revised

The chemical analyses of the heavily enriched glass(Table 4) show that all samples were melted with soda ashas flux their K2O MgO and P2O5 contents being higherthan those of the other samples (Figure 3) The low Al2O3content suggests that as well as flux a different silica sourcewas used to produce these samples Leslie et al [12] reportsome highly variable isotopic results from glass samples10thndash13th centuries in age from Rarsquos al-Hadd (Oman) one ofwhich is close to 20permil (Figure 4) Heavily enriched 12057518Ovalues which range from 216 to 226permil have already beenmeasured by Brill et al [2] on glass samples from Nimrud(Iraq) dated to the 7th century BC the author obviouslyconcluded that ldquothese glasses must represent a glassmaking

10 Journal of Chemistry

60 64 68 72 76 808

12

16

20N

a 2O

(wt

)

SiO2 (wt)

(a)

0 2 4 6

Natron

Soda plant ash

0

1

2

3

4

MgO

(wt

)

K2O (wt)

(b)

4 6 8 10 120

1

2

3

4

Al 2O

3 (w

t)

CaO (wt)

(c)

0 05 1 15 2 250

1

2

3

4

5

MnO

(wt

)

FeO (wt)

(d)

Figure 3 Na2O versus SiO2 (a) MgO versus K2O (b) Al2O3 versus CaO (c) and MnO versus FeO (d) contents of Greek glass samplessubdivided by provenance Thessaloniki Agora () Maroneia (I) Thessaloniki various sites (998779 natron glass 998771 soda ash glass) Meanchemical compositions and standard deviations of main compositional natron groups identified in literature and comparable with Greeksamples are also shown ldquoRomanrdquo glass (bold plus sign) Group 2 (bold multiplication sign) [22 35]

tradition thatmade use of some particular rawmaterialrdquo Twosamples from Aphrodisias (Turkey) 6th-7th centuries ADin age also yielded 12057518O values of about 234permil (Figure 4)All the samples reported in the literature with very positive12057518O values were obtained with soda ash as flux althoughthey show lowerK2OMgOandhigherNa2OK2Oratios thanGreek samples suggesting the use of different kinds of plantash

In Europe and Mediterranean area soda ash glass datesfrom the 9th century AD onwards [4 41] This wouldexclude a Roman age for Greek soda ash samples unlessthey were produced with raw glass imported from areas suchas Mesopotamia and Iran where plant ash continued to beused as flux in glass production throughout the period ofnatron dominance in the West [4] However so far chemicalcomparisons with 3rdndash7th-century soda ash glass from Iraq

Journal of Chemistry 11

7 6 2 8 6

12

16

20

24훿18O

(VSM

OW

)(permil

)

Number of samples

Figure 4 Comparisons among 12057518O(VSMOW) values of plant ash glasssamples [open symbols Thessaloniki various sites (◻)] and thosealready reported in the literature [full symbols glass from Nimrudand Aphrodisias (◼) [2] glass from Rarsquos al-Hadd (e) and Levantinesoda ash glass (X) [12] Medieval soda ash glass from Italy (998771) [3]]Number of analysed samples is also shown

[42 43] have not shown any consistency with Greek samplesIn addition the heavily enriched 12057518O values do indicatethat their raw materials differed from those normally used inRoman andMedieval glass production and this wouldmatchthe possibility of the different origin of these materials Theuse of ash as flux may cause some 18O enrichment when theash is particularly rich in carbonate bicarbonate and hydrate[4] but hardly to this extent Previous oxygen isotopic dataobtained on Medieval soda ash glass from the Western andEastern Mediterranean (Figure 4) indicate that the additionof ash did not contribute to isotopically heavy oxygen and the12057518Ovalues essentially reflect the silica source (eg [2 3 12])In the case of Greek heavily enriched glass the silica source isdifficult to identify taking into account the fact that quartzwith anomalously heavy isotopic composition is uncommoninmagmatic sedimentary or metamorphic rocks Due to thelarge oxygen isotopic fractionation between SiO2 andwater atlow temperatures biogenic silica and chert have the highest18O16O ratios observed in rocks [44] Therefore the Greeksamples with high isotopic values may be the product oflocal glass workshops which used raw materials composedof chert with the addition of ash probably obtained fromvarious plant species other than those considered by Titeet al [4] or differently pretreated The isotopic chemicaland mineralogical data obtained on a selection of chertsamples from the quarries in Triadi of Thessaloniki (CentralMacedonia Greece) furtherly support the hypothesis of localproduction at least if we consider sample Trd 1-5 composedof only quartz

In the case of samples with moderate 18O enrichmentseveral causes must be considered to explain their valuesSample 3-3 (12057518O= 186permil) has a chemical composition quiteclose to that of Roman glass decolourised by the addition ofMn [45] sample 6-3 (12057518O= 173permil) is chemically comparableto ldquoGroup 2rdquo of Foy et al [22] and its suggested age (6thcentury AD) matches the chronological diffusion of the ref-erence group However both samples have 12057518O higher thanthe average ldquoRomanrdquo or ldquoHIMTrdquo values

In view of the high Na2O content of samples 3-3 and 6-3(Table 4) 18O enrichment may be explained by remelting ofprevious glass with addition of further amounts of natron asflux which causes an increase in Na2O concentration and inthe 18O content of the final products

Apart from their slightly higher 12057518O values (161 and164permil resp) samples 3-4 and 10-4 show quite differentchemical compositions Sample 3-4 is chemically comparablewith ldquoGroup 2rdquo [22] the chronological diffusion ofwhich alsomatches the age proposed (5th-6th centuries AD) whereassample 10-4 is similar to Roman glass 1stndash3rd centuries Adin age although the presence of Cu and Pb may also indicaterecycling of coloured and opaque glass as in the case ofsample 7-1 Both samplesmay be produced in local secondaryworkshops by recycling previous glass (perhaps from theLevantine area) with the addition of further amounts ofnatron as flux as suggested by their high Na2O content(Table 4) thus increasing the 18Ocontent of the final product

According to its chemical composition sample 13-4(Table 4 12057518O= 173permil) was obtained with soda ash as flux asdeduced from its high K2O MgO and P2O5 contents Wesuggest a different starting material for this sample as in thecase of other soda plant ash glass identified in the Greekassemblage

Lastly sample 8-4 from Thessaloniki has 12057518O of 156permilthat is within the average Roman values suggesting the use ofBelus or Volturno sand and Egyptian natron as rawmaterialsbut its chemical composition is comparable to that of glassproduced with soda plant ash as flux The chronologicaldiffusion of soda ash glass in Europe andMediterranean area[4 41] excludes a Roman age for this sample and chem-ical comparisons with 3rdndash7th-century soda ash glass fromIraq [42 43] where plant ash continued to be used as fluxthroughout the period of natron dominance in the West [4]have not shown any consistency with the present sampleTherefore great uncertainty remains in the case of sample 8-4 as regards both its age and provenance also in view of theheavily enriched oxygen signatures of other soda ash samplesidentified here (Table 4) However sample 8-4 differs fromthe others due to its lower SiO2 (616 wt) and higher Al2O3(390wt) which suggest a different silica source probably asilica sand rich in feldsparsThis source may be characterisedby a less positive oxygen signature probably related to thefeldspars content of the sand which influences the 18Ocontent of the final productThis hypothesis is also supportedby the isotopic and chemical signatures of sample 13-4Obtained again with soda plant ash as flux this sample hasAl2O3 content intermediate between that of sample 8-4 andall other Greek soda ash samples and consequently shows anintermediate 12057518O value

12 Journal of Chemistry

4 Conclusions

The results of the present study emphasize the importanceof measuring the oxygen isotopic and chemical compositionsof glass samples in order to constrain some features such asage raw materials and production technology Comparisonsof our isotopic and chemical data with those reported in theliterature particularly in the case of glass from the Levantinearea are of particular interest as regards the trading ofraw glass to secondary workshops in Greece although forsome samples obtained with soda ash as flux and heavilyenriched in 18O production from local raw materials cannotbe completely excluded

In summary the thirty-nine glass samples from northernGreece studied here have oxygen isotopic compositionswhich allow them to be subdivided into three groups

The first is composed of twenty-nine samples (severalfrom Thessaloniki and all those from Maroneia) with 12057518Ovalues equal or very close to themean value of Roman glassesfrom European and Middle Eastern areas These similaritiesimply their production with raw materials with equal or veryclose oxygen isotopic composition such as sand from therivers Belus in Palestine and Volturno in Italy as suggestedby Pliny the Elder In contrast with the remarkable isotopichomogeneity heterogeneous chemical compositions allowthe subdivision of these samples into several subgroupswhich are compared with major compositional groups iden-tified in the Western Mediterranean during the first millen-nium AD

Seven samples from Thessaloniki and all the samplesfrom Maroneia show chemical similarity with ldquoGroup 2rdquo ofFoy et al [22] while one sample shows chemical simi-larity with HIMT glass Accordingly their age should beconstrained to the late Antique period for the Thessalonikiglass and confirmed for the Maroneia samples (ie 4thndash6thcenturies AD) Nine samples from Thessaloniki are chemi-cally comparable with Roman glass although they differ incolouringdecolouring elements and recycling indicators Inparticular in some samples the identification of manganeseintentionally added as a decolourant allows us to constraintheir age according to the chronological diffusion reported inthe literature of this decolourant that is from the 3rd to 4thcenturies AD Lastly three samples from Thessaloniki(1stndash6th centuries AD) with 12057518O values comparable withldquoRomanrdquo values have chemical compositions very differentfrom ldquotypicalrdquo Roman glass suggesting different productiontechnologies

The second isotopic group is composed of four samplesfrom Thessaloniki showing heavily enriched 12057518O values(205 to 227permil) their chemical analyses indicate that theywere obtained using soda ash as flux which has little effect onthe final oxygen isotopic composition of glass These high12057518O values may be explained by the use of silica rawmaterials with heavy 18O enrichment such as chert which isalso found in the Thessaloniki region Therefore these sam-ples may be the product of local glass factories

The third group is composed of five samples from Thes-saloniki showing moderate 18O enrichment (161 to 186permil)

From the chemical point of view four samples are natronglass with compositions similar to Roman or ldquoweakrdquo HIMTgroups and one is a soda ash glass In the case of natron glassthe moderate 18O enrichment may be obtained by recyclingglass (perhaps from the Levantine area) in local secondaryworkshops with the addition of further amounts of natron asflux as suggested by their high Na2O contents In the case ofsoda ash themoderate 18O enrichment with respect to otherGreek soda ash glass may be due to the use of less positivesilica source

In conclusion these interesting results the first obtainedon glass samples from northern Greece support trades andcommercial exchanges between theNear East andGreece andsuggest although further data are required to confirm it thatthe ldquofingerprintrdquo ofGreek glass production could be related tothe use of local chert and soda ash as possible raw materials

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

The authors are grateful to D Grammenos director ofthe Archaeological Museum of Thessaloniki for providingglass samples from Thessaloniki R Carampin (Istituto diGeoscienze e Georisorse Sezione di Padova CNR) F Gallo(Dipartimento dei Beni Culturali Universita di Padova) andD Pasqual (Dipartimento diGeoscienze Universita di Padova)are thanked for their kind support to execution of chemicalanalyses Financial support was provided by ldquoEx 60rdquo fundsof the University of Padova (principal investigator AlbertaSilvestri)

References

[1] R Newton andD DavisonConservation of Glass Butterworth-Heinemann Oxford UK 1999

[2] R H Brill R N Clayton T K Mayeda and C P StapletonldquoOxygen isotope analyses of early glassesrdquo in Chemical Analysesof Early Glasses R H Brill Ed vol 2 pp 303ndash322 CorningMuseum of Glass New York NY USA 1999

[3] A Silvestri A Longinelli andGMolin ldquo12057518Omeasurements ofarchaeological glass (Roman toModern age) and rawmaterialspossible interpretationrdquo Journal of Archaeological Science vol37 no 3 pp 549ndash560 2010

[4] M S Tite A Shortland Y Maniatis D Kavoussanaki and S AHarris ldquoThe composition of the soda-rich and mixed alkaliplant ashes used in the production of glassrdquo Journal of Archae-ological Science vol 33 no 9 pp 1284ndash1292 2006

[5] C Antonaras ldquoGlass working in Roman and early ChristianThessaloniki older and more recent findsrdquo in Proceedings of theHistory Technology and Conservation of Ancient Metals Glassesand Enamels International Symposium Athens Greece Novem-ber 2011

[6] I Friedman and J R OrsquoNeil ldquoCompilation of stable isotopefractionation factors of geochemical interestrdquo in Data of

Journal of Chemistry 13

Geochemistry Geological Survey Professional Paper 440-KKchapter KK 1977

[7] A Silvestri and A Marcante ldquoThe glass of Nogara (Verona) aldquowindowrdquo on production technology of mid-Medieval times inNorthern Italyrdquo Journal of Archaeological Science vol 38 no 10pp 2509ndash2522 2011

[8] S Alberta M Gianmario and P Valentina ldquoThe stained glasswindow of the southern transept of St Anthonyrsquos Basilica(Padova Italy) study of glasses and grisaille paint layersrdquoSpectrochimica ActamdashPart B Atomic Spectroscopy vol 66 no1 pp 81ndash87 2011

[9] K Govindaraju ldquoCompilation of working values and sampledescription for 383 geostandardsrdquoGeostandards Newsletter vol18 pp 1ndash158 1994

[10] A Savitzky andM J EGolay ldquoSmoothing anddifferentiation ofdata by simplified least squares proceduresrdquo Analytical Chem-istry vol 36 no 8 pp 1627ndash1639 1964

[11] J Henderson J A Evans H J Sloane M J Leng and CDoherty ldquoThe use of oxygen strontium and lead isotopesto provenance ancient glasses in the Middle Eastrdquo Journal ofArchaeological Science vol 32 no 5 pp 665ndash673 2005

[12] K A Leslie I C Freestone D Lowry and M Thirlwall ldquoTheprovenance and technology of Near Eastern glass oxygenisotopes by laser fluorination as a complement to strontiumrdquoArchaeometry vol 48 no 2 pp 253ndash270 2006

[13] R H Brill ldquoScientific investigations of the Jalame glass andrelated findsrdquo in Excavations at Jalame Site of a Glass Factory inLate Roman Palestine G D Wienberg Ed pp 257ndash293University of Missouri Press Columbia Mo USA 1988

[14] M Pomerancblum ldquoThe distribution of heavy minerals andtheir hydraulic equivalents in sediments of the Mediterraneancontinental shelf of Israelrdquo SEPM Journal of SedimentaryResearch vol 36 pp 162ndash174 1966

[15] D J Stanley Y Mart and Y Nir ldquoClay mineral distributions tointerpret Nile cell provenance and dispersal II Coastal plainfrom Nile delta to northern Israelrdquo Journal of Coastal Researchvol 13 no 2 pp 506ndash533 1997

[16] M B Hatzopoulos and L D Loukopoulou Morrylos Centrede Recherches de lrsquoAntiquite Grecque et Romaine AthenesGreece 1989

[17] E Dotsika D Poutoukis I Tzavidopoulos Y Maniatis DIgnatiadou and B Raco ldquoA natron source at Pikrolimni Lake inGreece Geochemical evidencerdquo Journal of Geochemical Explo-ration vol 103 no 2-3 pp 133ndash143 2009

[18] H E Foster and C M Jackson ldquoThe composition of ldquonaturallycolouredrdquo late Roman vessel glass from Britain and the impli-cations for models of glass production and supplyrdquo Journal ofArchaeological Science vol 36 no 2 pp 189ndash204 2009

[19] I C Freestone ldquoAppendix chemical analysis of lsquorawrsquo glass frag-mentsrdquo in Excavations at Carthage Volume II1 The CircularHarbour North SideThe Site and FindsOther than Pottery H RHurst Ed British Academy Monographs in Archaeology N∘4p 290 Oxford University Press Oxford UK 1994

[20] I C Freestone M Ponting and M J Hughes ldquoThe origins ofByzantine glass from Maroni Petrera Cyprusrdquo Archaeometryvol 44 no 2 pp 257ndash272 2002

[21] D C W Sanderson J R Hunter and S E Warren ldquoEnergydispersive X-ray fluorescence analysis of 1stmillennium ad glassfrom Britainrdquo Journal of Archaeological Science vol 11 no 1 pp53ndash69 1984

[22] D Foy M Picon M Vichy and V Thirion-Merle ldquoCar-acterisation des verres de la fin de lrsquoAntiquite en Mediterraneeoccidentale lrsquoemergence de nouveaux courants commerciauxrdquoin Echanges et Commerce du Verre dans le Monde Antique DFoy and M D Nenna Eds Actes du Colloque de lrsquoAssociationFrancaise pour lrsquoArcheologie du Verre Aix-en-Provence etMarseille June 2001 pp 41ndash85 Monique Mergoil MontagnacFrance 2003

[23] D Rosenow and T Rehren ldquoHerding cats Roman to LateAntique glass groups from Bubastis northern Egyptrdquo Journal ofArchaeological Science vol 49 no 1 pp 170ndash184 2014

[24] P Mirti A Casoli and L Appolonia ldquoScientific analysis ofroman glass from augusta praetoriardquo Archaeometry vol 35 no2 pp 225ndash240 1993

[25] A Silvestri G Molin and G Salviulo ldquoRoman and medievalglass from the Italian area bulk characterization and relation-ships with production technologiesrdquo Archaeometry vol 47 no4 pp 797ndash816 2005

[26] A Silvestri S Tonietto and G Molin ldquoThe palaeo-Christianglass mosaic of St Prosdocimus (Padova Italy) archaeometriccharacterisation of lsquogoldrsquo tesseraerdquo Journal of ArchaeologicalScience vol 38 no 12 pp 3402ndash3414 2011

[27] F Gallo and A Silvestri ldquoMedieval glass from Rocca di Asolo(northern italy) an archaeometric studyrdquoArchaeometry vol 54no 6 pp 1023ndash1039 2012

[28] F Gallo A Marcante A Silvestri and G Molin ldquoThe glass ofthe ldquoCasa delle Bestie Feriterdquo a first systematic archaeometricstudy on Late Roman vessels from Aquileiardquo Journal of Archae-ological Science vol 41 pp 7ndash20 2014

[29] S Maltoni T Chinni M Vandini E Cirelli A Silvestri andG Molin ldquoArchaeological and archaeometric study of the glassfinds from the ancient harbour of Classe (Ravenna-Italy) newevidencerdquo Heritage Science vol 3 no 1 article 13 2015

[30] A Ceglia P Cosyns K Nys H Terryn H Thienpont and WMeulebroeck ldquoLate antique glass distribution and consumptionin Cyprus a chemical studyrdquo Journal of Archaeological Sciencevol 61 pp 213ndash222 2015

[31] N Schibille A Sterrett-Krause and I C Freestone ldquoGlassgroups glass supply and recycling in late Roman CarthagerdquoArchaeological and Anthropological Sciences pp 1ndash19 2016

[32] A Cholakova T Rehren and I C Freestone ldquoCompositionalidentification of 6th c AD glass from the Lower DanuberdquoJournal of Archaeological Science Reports vol 7 pp 625ndash6322016

[33] S Conte T Chinni R Arletti and M Vandini ldquoButrint(Albania) between eastern and western Mediterranean glassproduction EMPA and LA-ICP-MS of late antique and earlymedieval findsrdquo Journal of Archaeological Science vol 49 no1 pp 6ndash20 2014

[34] I C Freestone S Wolf and M Thirlwall ldquoThe production ofHIMT glass elemental and isotopic evidencerdquo inAnnales du 16eCongres de lrsquoAssociation Internationale pour lrsquoHistoire du Verre(AIHV rsquo05) pp 153ndash157 London UK 2005

[35] M D Nenna M Picon and M Vichy ldquoAteliers primaries etsecondaries en Egypte a lrsquoepoque greco-romainerdquo in La Routedu Verre Ateliers Primaires et Secondaires du Second Millenaireav J-C au Moyen Age M D Nenna Ed vol 33 pp 97ndash112Travaux de la Maison de lrsquoOrient Mediterraneen 2000

[36] C M Jackson ldquoMaking colourless glass in the Roman periodrdquoArchaeometry vol 47 no 4 pp 763ndash780 2005

[37] E V Sayre ldquoThe intentional use of antimony and manganese inancient glassesrdquo in Advances in Glass Technology Part 2 F R

14 Journal of Chemistry

Matson and G Rindone Eds pp 263ndash282 Plenum Press NewYork NY USA 1963

[38] H E Foster and C M Jackson ldquoThe composition of lateRomano-British colourless vessel glass glass production andconsumptionrdquo Journal of Archaeological Science vol 37 no 12pp 3068ndash3080 2010

[39] J Henderson ldquoThe raw materials of early glass productionrdquoOxford Journal of Archaeology vol 4 no 3 pp 267ndash291 1985

[40] B Gratuze and K Janssens ldquoProvenance analysis of glassartefactsrdquo inNon-Destructive Microanalysis of Cultural HeritageMaterials K Janssens and R Van Grieken Eds pp 663ndash712Elsevier Amsterdam The Netherlands 2004

[41] J Henderson ldquoTradition and experiment in first millenniumAD glass productionmdashthe emergence of early Islamic glasstechnology in late antiquityrdquoAccounts of Chemical Research vol35 no 8 pp 594ndash602 2002

[42] P Mirti M Pace M M Negro Ponzi and M Aceto ldquoICP-MSanalysis of glass fragments of Parthian and Sasanian epoch fromSeleucia and Veh Ardasır (Central Iraq)rdquoArchaeometry vol 50no 3 pp 429ndash450 2008

[43] P Mirti M Pace M Malandrino and M N Ponzi ldquoSasanianglass from Veh Ardasır new evidences by ICP-MS analysisrdquoJournal of Archaeological Science vol 36 no 4 pp 1061ndash10692009

[44] J Hoefs Stable Isotope Geochemistry Springer Berlin Ger-many 5th edition 2004

[45] A Silvestri G Molin and G Salviulo ldquoThe colourless glass ofIulia Felixrdquo Journal of Archaeological Science vol 35 no 2 pp331ndash341 2008

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 201

International Journal ofInternational Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal ofInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

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Analytical Methods in Chemistry

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Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

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The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

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Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

4 Journal of Chemistry

Table 2 Isotopic and chemical composition of Roman and late Antique glasses from Thessaloniki Agora 1stndash6th century AD in age Notethat CoO and NiO contents are not reported because they are lower than EMPA detection limits for all samples (LOD of CoO and NiO =003wt)

Sample 12057518O SiO2 Na2O CaO Al2O3 K2O MgO FeO TiO2 MnO P2O5 SO3 Cl CuO ZnO SnO2 Sb2O3 PbONumber (VSMOW) Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt1-1 155 6617 1690 860 268 065 146 122 018 164 013 035 068 lt003 lt004 lt004 lt004 lt0082-1 156 6465 1496 614 316 094 149 111 020 148 065 016 065 067 004 089 lt004 2903-1 155 7148 1540 742 244 037 059 058 009 055 002 024 096 lt003 lt004 lt004 lt004 lt0084-1 156 6424 988 574 159 1147 348 030 003 lt005 130 007 064 lt003 lt004 lt004 009 lt0085-1 154 6768 1694 708 273 057 096 159 028 109 007 023 109 lt003 lt004 lt004 lt004 lt0086-1 155 7298 1700 498 209 056 051 029 009 lt005 001 022 090 lt003 lt004 lt004 025 lt0087-1 156 6543 1976 654 238 040 108 114 026 112 002 027 160 014 lt004 lt004 lt004 0338-1 155 6714 1683 786 292 091 129 165 020 145 026 025 054 lt003 lt004 lt004 lt004 lt0089-1 156 6553 1733 784 295 085 141 139 019 167 026 030 053 lt003 lt004 lt004 lt004 lt00810-1 155 7651 967 811 025 378 103 006 lt004 lt005 006 040 019 lt003 lt004 lt004 lt004 lt008

155 plusmn 007permilmean isotopic composition

was better than 1 for SiO2 Na2O and FeO better than 5for CaO K2O P2O5 and Sb2O3 and not worse than 12 forother major and minor elements

The chemical and mineralogical compositions of chertsamples were obtained bymeans of X-ray fluorescence (XRF)and X-ray powder diffraction (XRPD) respectively

X-ray fluorescence (XRF) was carried out on a PhilipsPW 2400 instrument equipped with a Rh tube with a ratedcapacity of 3 kW (60 kV125mA max) Three primary col-limators (150 300 and 700120583m spacing) and four analyticalcrystals (TlAp100 LiF200 Ge111 and PE002) were selectedThe spectrometer was interfaced with a personal computerwith SuperQ software (Philips) Instrumental parametersand analytical conditions are detailed in Alberta et al [8]Geological reference standards were used for calibration [9]Precision was better than 06 for major andminor elementsand about 3 for trace elements XRF accuracy was checkedby reference standards [9] and was within 05 wt for Silower than 3 for othermajor andminor elements and lowerthan 5 for traces The lowest detection limits of XRF werewithin 002wt for Al2O3 MgO and Na2O within 04 wtfor SiO2 and within 0005wt for TiO2 Fe2O3 MnO CaOK2O and P2O5 and range from 3 to 10 ppm for trace elementsFor this type of analysis chert fragments were crushed in anagatemortarThe resulting powders were heated in an oven at860∘C for 20min and then at 980∘C for 2 hours and the losson ignition (LOI) was determined The powders were thenmixed with Li2B4O7 at a 1 10 ratio and beads were prepared

XRPD data were obtained on a computer-controlledPhilips XrsquoPert PRO with Bragg-Brentano 120579-120579 geometry Thenormal-focus CuX-ray tube (CuK1205721 120582= 0154056 nm) oper-ated at 40KV and 20mA Data were recorded in the 2∘ndash70∘2120579 range in step-scan mode with step width increments of002∘ and a step counting time of 10 s Data were processedby the XrsquoPert HighScore (PANalytical copyright) 2120579 and 119889values were calculated with the second-derivative algorithmof Savitzky andGolay [10] All XRPDdiffraction profiles werecarried out on about 500mg of samples finely ground into anagate mortar

It should be stressed here that XRPD analyses werecarried out on all the chert samples while XRF analyseswere carried out only on samples Trd 1-2 and Trd 1-5 whichare representative of the two mineralogical compositionsidentified

3 Results and Discussion

31 Results The ten samples from the Thessaloniki Agorashow an extremely homogeneous oxygen isotopic composi-tion (154ndash156permil Table 2) All the samples from the churchof Maroneia 4thndash6th centuries AD in age also have isotopiccompositions ranging from 152 to 160permil with mean valueequal to 156plusmn025permil(Table 3)Theirmean isotopic values arepractically identical to those of the first set of samples fromThessaloniki although the range of values from Maroneia isslightly largerThe isotopic results obtained on the remainingnineteen glasses from Thessaloniki indicate that only ninesamples (4-3 5-3 7-3 4-4 5-4 6-4 7-4 11-4 and 14-4)have values very close to those measured in samples fromThessaloniki Agora and Maroneia (Table 4)

In contrast with the remarkable isotopic homogeneity ofthemajority ofGreek glass samples (2939 samples) chemicalcompositions are rather heterogeneous (Tables 2 3 and 4)In particular samples 1-1 5-1 8-1 9-1 (Table 2) 4-3 6-4 11-4 and 14-4 (Table 4) from Thessaloniki and all the samplesfrom Maroneia (Table 3) show SiO2 contents ranging from6448 to 6768wt Na2O from 1636 to 1846wt CaOfrom 702 to 907wt and Al2O3 from 229 to 292wtK2O and MgO contents are both lower than 15 wt in allthe considered samples although MgO is higher than K2O(MgO = 125 plusmn 015wt versus K2O = 070 plusmn 013wt)Thisgroup of samples also shows the highest iron titanium andmanganese contents (FeO from 080 to 212 wt TiO2 from014 to 037wt and MnO from 096 to 265wt) andnondetectable trace elements

The other glass samples from Thessaloniki (2-1 3-1 6-17-1 5-3 7-3 4-4 5-4 and 7-4) whose 12057518O is in the range153ndash156permil (Tables 2 and 4) also show comparable SiO2

Journal of Chemistry 5

Table 3 Isotopic and chemical composition of glasses fromMaroneia 4thndash6th centuries AD in age Note that CoO NiO CuO ZnO SnO2Sb2O3 and PbO contents are not reported because they are lower than EMPA detection limits for all samples (LOD of CoO NiO and CuO =003 wt LOD of ZnO SnO2 Sb2O3 = 004 wt LOD of PbO = 008 wt)

Sample 12057518O SiO2 Na2O CaO Al2O3 K2O MgO FeO TiO2 MnO P2O5 SO3 ClNumber (VSMOW) Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt1-2 154 6711 1739 784 229 061 110 106 015 154 007 030 1022-2 155 6623 1780 783 270 076 123 133 017 123 015 031 0923-2 156 6462 1770 898 240 072 147 104 016 182 012 034 0924-2 159 6564 1846 795 270 082 121 138 016 096 013 032 0915-2 156 6570 1738 825 238 059 121 088 015 169 009 034 0956-2 156 6679 1717 750 253 060 125 098 016 184 008 030 1007-2 157 6463 1796 907 257 071 150 110 018 172 013 033 0928-2 152 6556 1756 752 250 065 125 093 017 234 009 029 1019-2 160 6613 1814 783 273 084 122 128 015 099 016 034 09010-2 153 6659 1636 859 240 069 111 088 017 160 011 036 087

156 plusmn 02permilmean isotopic composition

Table 4 Isotopic and chemical composition of Roman and late Antique glasses from Thessaloniki 1stndash6th centuries AD in age Sampleswith moderate and strong 18O enrichment are in italics and bold font respectively Note that NiO ZnO and SnO2 contents are not reportedbecause they are lower than EMPA detection limits for all samples (LOD of NiO = 003wt LOD of ZnO and SnO2 = 004wt)

Sample 12057518O SiO2 Na2O CaO Al2O3 K2O MgO FeO TiO2 MnO P2O5 SO3 Cl CoO CuO Sb2O3 PbONumber (VSMOW) Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt1-3 226 6746 1300 974 117 485 201 058 006 096 069 007 128 lt003 lt003 lt004 lt0082-3 225 6731 1320 980 115 477 200 057 005 096 066 007 129 lt003 lt003 lt004 lt0083-3 186 6695 1946 671 221 043 096 063 010 127 010 025 143 lt003 lt003 lt004 lt0084-3 158 6420 1767 702 285 040 128 212 037 265 010 040 123 lt003 lt003 lt004 lt0085-3 156 6789 1617 864 268 053 083 044 007 136 007 035 119 lt003 lt003 lt004 lt0086-3 173 6492 1919 821 232 059 106 094 014 158 007 045 087 lt003 lt003 lt004 lt0087-3 152 7162 1553 647 263 065 042 026 004 033 009 003 106 lt003 lt003 lt004 lt0083-4 161 6478 1862 775 237 059 119 115 015 152 005 044 093 lt003 lt003 lt004 lt0084-4 153 6732 1696 785 252 031 088 072 022 161 001 028 136 lt003 lt003 lt004 lt0085-4 153 6678 1796 652 240 050 095 079 021 166 002 029 119 lt003 lt003 lt004 lt0086-4 153 6525 1746 783 246 062 100 080 015 192 005 047 099 lt003 lt003 004 lt0087-4 153 6580 1876 630 189 054 087 067 010 077 004 031 146 lt003 178 lt004 lt0088-4 156 6156 1248 1003 390 495 193 079 017 073 043 014 088 lt003 lt003 004 0509-4 227 6780 980 921 110 545 235 051 005 067 052 010 091 lt003 lt003 004 lt00810-4 164 6546 1983 636 248 049 116 117 016 011 001 052 123 004 021 lt004 06311-4 154 6451 1791 864 265 076 118 143 014 066 011 045 098 lt003 lt003 lt004 lt00812-4 205 6272 1179 945 134 440 204 092 006 438 039 013 105 lt003 lt003 006 lt00813-4 173 6444 1268 964 234 423 207 076 012 121 042 016 101 lt003 lt003 004 01414-4 156 6448 1781 723 258 079 134 197 015 115 014 054 098 lt003 lt003 lt004 lt008

Na2O CaO K2O and MgO contents with the previousglass samples although they differ in contents of colour-ingdecolouring elements for example iron copper man-ganese and antimony and minor elements for example tinand lead (Tables 2 and 4) In particular samples 5-3 4-4 and5-4 show concentrations of manganese higher than 1 wtwhereas sample 6-1 has nomanganese but antimony (Table 2)Instead samples 3-1 and 7-3 do not reveal any manganeseor antimony (Tables 2 and 4) Sample 2-1 from ThessalonikiAgora has relatively high concentrations of CuO SnO2 PbO

and P2O5 (Table 2) The chemical composition of sample7-1 is comparable with that of sample 2-1 except for thelower copper and lead contents (Table 2) Lastly samples 4-1 and 10-1 from Thessaloniki Agora which have comparable12057518Ovalues show chemical compositions different from eachother except for the similar (and relatively low) content ofsodium (about 10 wt Na2O) and the absence of manganeseand trace elements in both samples In particular sample 4-1has lower SiO2 and CaO and higher Al2O3 K2O MgO FeOP2O5 and Cl than sample 10-1 (Table 2)

6 Journal of Chemistry

Table 5 12057518O(VSMOW) of chert samples from the quarries in Triadiof Thessaloniki (Central Macedonia Greece)

Samples 12057518O(VSMOW) MeanTrd 1-1 250 251 250Trd 1-2 234 235 234Trd 1-4 236 238 237Trd 1-5 260 261 260Trd 2-1 242 244 243Trd 3-1 261 260 260Trd 3-2 258 260 259Trd 5-2 225 223 224

Mean value 246 plusmn 14permil

Lastly sample 8-4 fromThessaloniki with 12057518O equal to156permil is characterised by lower silicium and sodium con-tents and higher calcium aluminium potassium magne-sium and phosphorous contents (Table 4) than other glasseswith comparable isotopic composition

In addition to samples with isotopic signatures rangingfrom 152 to 160permil the isotopic data indicate that foursamples fromThessaloniki are heavily enriched by about 7permilsample 12-4 has 12057518O equal to 205permil and samples 1-3 2-3and 9-4 have values from 225 to 227permil Finally other fivesamples fromThessaloniki (3-3 6-3 3-4 10-4 and 13-4) showmoderate 18O enrichment with values between 161 and186permil (Table 4)

The chemical analyses of the heavily enriched glass(Table 4) show that all samples are characterised by higherCaO K2O MgO and P2O5 and lower Na2O and Al2O3contents than other Greek samples with lower isotopic com-position In addition sample 12-4 also has exceptionally highmanganese (MnO = 438wt Table 4)

The samples with moderate 18O enrichment show quitevariable chemical compositions but comparable to those ofsamples with lower and higher isotopic compositions Sam-ples 3-3 (12057518O= 186permil) and 10-4 (12057518O= 164permil) have chem-ical compositions comparable to those of samples 5-3 4-4and 5-4 although sample 10-4 has very little Mn and highCu and Pb (Table 4) Sample 6-3 (12057518O = 173permil) is similarin chemical composition to samples 1-1 5-1 8-1 91 4-3 6-4 11-4 and 14-4 from Thessaloniki (Tables 2 and 4) and allthe samples from Maroneia (Table 3) Finally the chemicalcomposition of sample 13-4 (12057518O = 173permil) is very similar tothose of the heavily enriched glass as deduced from itslow Na2O and Al2O3 and high CaO K2O MgO and P2O5contents (Table 4)

The isotopic data obtained on the chert samples from thequarries in Triadi ofThessaloniki show that mean 12057518O value(equal to 246 plusmn 14permil Table 5) is comparable to those ofGreek glass samples heavily enriched (mean 12057518O value =221 plusmn 11permil) Mineralogical data obtained by means ofXRPD show chert samples are a mixture of quartz andgoethite (semiquantitative contents of the two phases 94quartz and 6 goethite) except for sample Trd 1-5 composedof only quartz (Figure 1)

XRF data furtherly confirm the mineralogical composi-tions sample Trd 1-2 being almost entirely composed of SiO2and Fe2O3 and Trd 1-5 of only SiO2 (Table 6)

32 Discussion The majority of the analysed samples fromThessaloniki and all the samples from Maroneia have ahomogeneous oxygen isotopic composition (12057518O value =156 plusmn 025permil Table 2 and Figure 2) which is equal orvery close to the mean value of ldquoRomanrdquo glass as deducedfrom a set of isotopic measurements on glass from Europedated from the 1st to the 4th centuries AD which show arelatively narrow range of 12057518O (from about 154permil to 160permil)[2 3] Similar results (Figure 2) were also obtained for lateAntiqueearly Medieval samples from Grado and Vicenzatwo sites in Northern Italy [3] and for coeval glass from theNear East [11 12]

These similarities may be explained by assuming thatthe Greek glass samples were produced with raw materialswith equal or very similar oxygen isotopic compositionSand from the rivers Belus in Palestine and Volturno inItaly mentioned by Pliny the Elder in Naturalis Historia asmaterials for making glass is suitable for glass productionand has the same oxygen isotopic composition when theVolturno sandundergoes selective grinding [3] It follows thatglass produced with either Belus or Volturno sand as networkformer and natron as flux is practically indistinguishablefrom the oxygen isotopic point of view Consequently theisotopic composition of most of the Greek samples in Tables2 3 and 4 cannot help to distinguish among glass samplesimported from Italy or the Near East or glass samplesproduced inGreek secondary glassworkshops bymelting rawglass from the geographic point of view a Levantine originfor the Greek glass samples is quite reasonable This origin isreinforced by data reported in Brill [13] on five cullets froman ancient glass workshop at Jalame in western Galilee (3rd-4th centuries AD) The author suggests that the silica usedfor these cullets came from sand taken from the mouth ofthe Belus and that the oxygen isotopic composition of quartzwas enriched in 18O by the calcium carbonate contained inthe sand in the form of sea shells with natron as flux The12057518O values of the Jalame glass are slightly lower than thoseof Greek samples and range from about 14 to 15permil (Figure 2)Although the use of various other raw materials cannot becompletely excluded this small difference may be explainedby amounts of natron used for melting which are slightlysmaller in Jalame than in Greek glass samples The oxygenisotopic study carried out by Silvestri et al [3] on Romannatron glass demonstrated the ldquopositive natron effectrdquo that isit is presumed that flux which has very positive 12057518O valuescaused 18O enrichment in the final glass as confirmed bythe plot of Na2O versus 12057518O which clearly shows a positivecorrelation Other glass samples from the Near East have12057518O values close to those of our samples showing ldquoRomanrdquovalues (Figure 2) These samples measured by Leslie et al[12] came from different locations three from the BethShersquoan in Israel (6th-7th centuries AD) mean value 146permilthree from Tel el-Ashmunein in Egypt (8th-9th centuries)mean value 148permil and three from Carthage in Tunisia

Journal of Chemistry 7

10 20 30 40 50 60 70

Cou

nts

0

TRD-1-2

Peak list

Goethite syn FeO(OH)

50000

100000

150000

Quartz low SiO2

Position (∘2휃) (copper (Cu))

(a)

TRD-1-5

10 20 30 40 50 60 70

Cou

nts

Peak list

0

100000

200000

Quartz low SiO2

Position (∘2휃) (copper (Cu))

(b)

Figure 1 XRPD patterns of chert samples named Trd 1-2 (a) and Trd 1-5 (b) representative of the twomineralogical compositions identified

(4thndash6th centuries) mean value 150permil All these samplesare obtained using natron from the evaporitic lakes of WadiNatron in Egypt The provenance of sand from a relativelyshort stretch of the eastern Mediterranean coast is suggestedfor the Beth Shersquoan samples and the similarity between thedelta values of the Tel el-Ashmunein and Carthage samplesis explained by their production with the same Egyptiansand The isotopic similarity among these three groups ofsamples can be explained taking into account a commonprovenance for natron and that Levantine sand comes fromEgypt and is transported up to the eastern Mediterraneancoast by sea currents [14 15] therefore the use of sandand flux with similar provenance yields glass samples withsimilar isotopic compositions The same source may thusbe hypothesised for the Greek glass samples analysed hereHowever it should be stressed that natural natron depositsin the region of Macedonia in northern Greece were well-known in the time of Plato (5th century BC) and werealso described by Pliny the Elder in his Naturalis HistoriaeHatzopoulos and Loukopoulou [16] identified Lake Chalastra(so-called in antiquity that is the place where the ldquoCha-lastraion nitronrdquo formed and dissolved over a period of afew days) as the modern lake of Picrolimni located about20 km NW of Thessaloniki The geochemical conditionsresponsible for the formation of ldquoChalastraion nitronrdquo haverecently been studied and discussed by Dotsika et al [17]The salts deposited by the lake brine were mineralogicallyidentified by XRD analysis and include not only calcite anddolomite but also trona (Na2CO3sdotNaHCO3sdot2H2O) burkeite(Na2CO3sdot2Na2SO4) and halite (NaCl) thus confirming themineralogical similarity between these deposits and thosefrom Wadi Natron in Egypt However the oxygen isotopiccompositions determined on the Picrolimni salt deposits

range from about 11 to 25permil (VSMOW) much lower than thevalues for Wadi Natron (about 34 to 40permil [2 3]) Thereforein the case of our samples use of ldquoChalastraion nitronrdquo as fluxcan hardly be considered

In contrast with the remarkable isotopic homogeneity ofthe majority of Greek samples (2939 samples) the chemicalcomposition is rather heterogeneous (Tables 2 3 and 4)although they are all obtainedwith natron as flux having bothK2O and MgO contents lower than 15 wt In particularsamples 1-1 5-1 8-1 9-1 4-3 6-4 11-4 and 14-4 fromThessaloniki (Tables 2 and 4) and all the samples fromMaroneia (Table 3) show the HIMT (High Iron Magnesiumand Titanium) signature This reference group is defined byhigh levels of iron (ge07 wt)manganese (usually sim1-2 wt)magnesium (usuallyge08 wt) and titanium (ge01 wt) andits yellow-green colour is due to the amount of iron sugges-tive of a relatively impure sand source [18] These also are thekey characteristics of Greek glass samples which have highFeO (120 plusmn 031wt) MnO (154 plusmn 035wt) MgO (124 plusmn016wt) and TiO2 (018plusmn005wt) contentsThe acronymHIMT was first applied by Freestone [19] to raw glass fromCarthage and glass vessels from Cyprus [20] although glasswith high contents of iron manganese and titanium wasalready identified by Sanderson et al [21] However all theGreek samples (except 4-3) containing about 50ndash60 of theamount of iron titanium and manganese oxides measuredin ldquotypicalrdquo HIMT glass such as Group 1 of Foy et al [22](about 121 plusmn 031wt as FeO 017 plusmn 003wt as TiO2and 151 plusmn 037wt as MnO versus 2 plusmn 08wt as FeO05 plusmn 01wt as TiO2 and 22 plusmn 04wt as MnO for Greeksamples and Group 1 resp) show a better fit with ldquoGroup 2rdquoof Foy et al [22] whichmay be considered as a ldquoweakrdquo HIMTglass [18] due to lower contents of the key oxides of HIMT

8 Journal of Chemistry

Table6Ch

emicalcompo

sitions

ofchertsam

plesn

amed

Trd1-2

andTrd1-5

representativeof

thetwomineralogicalcompo

sitions

identifi

ed(X

RFdataL

OIlosson

ignitio

n)N

otethat

GaYNbLaC

eandUcontentsaren

otrepo

rted

becausetheyarelow

erthan

XRFdetectionlim

itsfora

llsamples

(LODof

Ga=

5ppm

LODof

YNbandU=3p

pmLODof

LaandCe=

10pp

m)

Sample

SiO2

TiO2

Al 2O3

Fe2O3

MnO

MgO

CaO

Na 2O

K 2O

P 2O5

LOI

ScV

CrCo

Ni

CuZn

RbSr

ZrBa

Nd

PbTh

Num

berWt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

Trd1-2

9068

001

021

713

015

037

012

005

001

002

218

9314

507

124

146

1846

78

920

1912

7Trd1-5

9998lt00

05lt00

2lt00

05lt00

05lt00

2lt00

05lt00

2lt00

05lt00

05000lt3lt3lt3lt3lt3lt3lt3lt3lt3lt3lt10lt10lt10lt3

Journal of Chemistry 9

10 11 42 10 9 5 9 16 414

15

16

17

18

19

Number of samples

훿18O

(VSM

OW

)(permil

)

Figure 2 Comparisons among 12057518O(VSMOW) values of natron glasssamples [open symbols Thessaloniki Agora (◻) Maroneia ()Thessaloniki various sites (998779)Thessaloniki glass withmoderate 18Oenrichment (I)] and those already reported in the literature [fullsymbols Roman glass from Europe (◼) [2] Roman glass from IuliaFelix (X) [3] 4th century AD glass from Jalame (998771) [2] HIMTglass from Carthage and Levantine natron glass (bold plus sign)[12] late Antique-earlyMedieval glass fromGrado ad Vicenza (boldmultiplication sign) [3]] Number of analysed samples is also shown

glass (Figure 3) Instead sample 4-3 has FeO TiO2 andMnO contents (Table 4) perfectly comparable with ldquotypicalrdquoHIMT glass [18 22] In general HIMT glass has also beenidentified in Britain [18] Egypt [23] France [22] Italy [24ndash29] Cyprus [20 30] Carthage [31] Bulgaria [32] andAlbania[33] The chemical and isotopic signatures of HIMT glass aresuggestive of continental sand sources of high maturity richin heavy minerals and located in the Near East probablyin Egypt [12 31 34] As regards the dating of the referencegroups in general terms the HIMT group is probably morecharacteristic of the period from the mid-4th century ADonwards although according to current research its compo-sition seems to have continued after the 5th century [18]In addition according to Schibille et al [31] ldquoGroup 2rdquo isdated to the 5th-6th centuries and is thus coeval with theglass from Maroneia Consequently the age of Thessalonikiglass samples similar in composition to those of ldquoGroup 2rdquois constrained to the late Antique period

The other glass samples from Thessaloniki (2-1 3-1 6-17-1 5-3 7-3 4-4 5-4 and 7-4) whose 12057518O is in therange of ldquoRomanrdquo values also show the chemical compo-sition typical of Roman glass [35] although they differ incontents of manganese and antimony (Figure 3) and traceelements In particular samples 3-1 5-3 4-4 and 5-4 showMnO gt 05 wt which suggests its intentional addition asa decolouriser [36] whereas sample 6-1 has no manganesebut antimony (Table 2) As these two elements the principal

decolourisers used between the 1st and 4th centuries ADwere both predominant from the late 1st to the 3rd centuriesand as the use of manganese increased from the end of the3rd to the 4th century [36ndash38] the age of these samples isconstrained accordingly Instead samples 3-1 and 7-3 do notreveal any intentional addition of decolouriser having noantimony and MnO lt 05 wt (Tables 2 and 4) Sample 2-1from Thessaloniki Agora has relatively high concentrationsof CuO SnO2 PbO and P2O5 (Table 2) suggesting theinclusion of cullet perhaps coloured and opaque mosaictesserae containing high quantities of one or more of theseelements in the glass batch The chemical composition ofsample 7-1 is not far from that of sample 2-1 although the con-centrations of copper and lead are much lower than those insample 2-1 (Table 2) This indicates that the presence ofthe above elements is due to recycling of earlier colouredglass because they occur in concentrations higher than thoseattributable to impurities in the raw materials but too low tohave any technological significance [39] Conversely the highCu in sample 7-4 not associated with high Sn Co Pb Sband Zn (Table 4) suggests that this element was intentionallyadded to produce the aquamarine colour

Lastly chemical similarities between samples 4-1 and 10-1from Thessaloniki Agora and data reported in the literatureare difficult to establish Sample 4-1 seems quite comparablewith some soda-potash-lime glass from the 14th-centuryworkshop at Saint-Chely (France) Two different hypothesesboth equally valid from an analytical point of view are pro-posed to explain the peculiar chemical composition of theseLate Medieval French samples [40] both soda and potashash were used by the glass-workers soda ash remaining themain component recycled glass from the surrounding areaswith both potash and soda ash compositions was used asrawmaterials Sample 10-1 also approaches although not per-fectly the composition of ldquomixed soda-potash glassrdquo dated toLate Bronze age [40] and the oxygen isotopic data obtained byBrill et al [2] on some Late Bronze age objects are also quitecomparable with that of sample 10-1 On the contrary oxygenisotope data on samples with chemical composition similarto sample 4-1 are unfortunately still lacking although dataon Medieval soda ash and late Medieval and modern potashash glass are systematically lower and range from about 12to 145permil [2 3] In any case both isotopic and chemical datasuggest that the age proposed for samples 4-1 and 10-1 fromThessaloniki Agora should be revised

The chemical analyses of the heavily enriched glass(Table 4) show that all samples were melted with soda ashas flux their K2O MgO and P2O5 contents being higherthan those of the other samples (Figure 3) The low Al2O3content suggests that as well as flux a different silica sourcewas used to produce these samples Leslie et al [12] reportsome highly variable isotopic results from glass samples10thndash13th centuries in age from Rarsquos al-Hadd (Oman) one ofwhich is close to 20permil (Figure 4) Heavily enriched 12057518Ovalues which range from 216 to 226permil have already beenmeasured by Brill et al [2] on glass samples from Nimrud(Iraq) dated to the 7th century BC the author obviouslyconcluded that ldquothese glasses must represent a glassmaking

10 Journal of Chemistry

60 64 68 72 76 808

12

16

20N

a 2O

(wt

)

SiO2 (wt)

(a)

0 2 4 6

Natron

Soda plant ash

0

1

2

3

4

MgO

(wt

)

K2O (wt)

(b)

4 6 8 10 120

1

2

3

4

Al 2O

3 (w

t)

CaO (wt)

(c)

0 05 1 15 2 250

1

2

3

4

5

MnO

(wt

)

FeO (wt)

(d)

Figure 3 Na2O versus SiO2 (a) MgO versus K2O (b) Al2O3 versus CaO (c) and MnO versus FeO (d) contents of Greek glass samplessubdivided by provenance Thessaloniki Agora () Maroneia (I) Thessaloniki various sites (998779 natron glass 998771 soda ash glass) Meanchemical compositions and standard deviations of main compositional natron groups identified in literature and comparable with Greeksamples are also shown ldquoRomanrdquo glass (bold plus sign) Group 2 (bold multiplication sign) [22 35]

tradition thatmade use of some particular rawmaterialrdquo Twosamples from Aphrodisias (Turkey) 6th-7th centuries ADin age also yielded 12057518O values of about 234permil (Figure 4)All the samples reported in the literature with very positive12057518O values were obtained with soda ash as flux althoughthey show lowerK2OMgOandhigherNa2OK2Oratios thanGreek samples suggesting the use of different kinds of plantash

In Europe and Mediterranean area soda ash glass datesfrom the 9th century AD onwards [4 41] This wouldexclude a Roman age for Greek soda ash samples unlessthey were produced with raw glass imported from areas suchas Mesopotamia and Iran where plant ash continued to beused as flux in glass production throughout the period ofnatron dominance in the West [4] However so far chemicalcomparisons with 3rdndash7th-century soda ash glass from Iraq

Journal of Chemistry 11

7 6 2 8 6

12

16

20

24훿18O

(VSM

OW

)(permil

)

Number of samples

Figure 4 Comparisons among 12057518O(VSMOW) values of plant ash glasssamples [open symbols Thessaloniki various sites (◻)] and thosealready reported in the literature [full symbols glass from Nimrudand Aphrodisias (◼) [2] glass from Rarsquos al-Hadd (e) and Levantinesoda ash glass (X) [12] Medieval soda ash glass from Italy (998771) [3]]Number of analysed samples is also shown

[42 43] have not shown any consistency with Greek samplesIn addition the heavily enriched 12057518O values do indicatethat their raw materials differed from those normally used inRoman andMedieval glass production and this wouldmatchthe possibility of the different origin of these materials Theuse of ash as flux may cause some 18O enrichment when theash is particularly rich in carbonate bicarbonate and hydrate[4] but hardly to this extent Previous oxygen isotopic dataobtained on Medieval soda ash glass from the Western andEastern Mediterranean (Figure 4) indicate that the additionof ash did not contribute to isotopically heavy oxygen and the12057518Ovalues essentially reflect the silica source (eg [2 3 12])In the case of Greek heavily enriched glass the silica source isdifficult to identify taking into account the fact that quartzwith anomalously heavy isotopic composition is uncommoninmagmatic sedimentary or metamorphic rocks Due to thelarge oxygen isotopic fractionation between SiO2 andwater atlow temperatures biogenic silica and chert have the highest18O16O ratios observed in rocks [44] Therefore the Greeksamples with high isotopic values may be the product oflocal glass workshops which used raw materials composedof chert with the addition of ash probably obtained fromvarious plant species other than those considered by Titeet al [4] or differently pretreated The isotopic chemicaland mineralogical data obtained on a selection of chertsamples from the quarries in Triadi of Thessaloniki (CentralMacedonia Greece) furtherly support the hypothesis of localproduction at least if we consider sample Trd 1-5 composedof only quartz

In the case of samples with moderate 18O enrichmentseveral causes must be considered to explain their valuesSample 3-3 (12057518O= 186permil) has a chemical composition quiteclose to that of Roman glass decolourised by the addition ofMn [45] sample 6-3 (12057518O= 173permil) is chemically comparableto ldquoGroup 2rdquo of Foy et al [22] and its suggested age (6thcentury AD) matches the chronological diffusion of the ref-erence group However both samples have 12057518O higher thanthe average ldquoRomanrdquo or ldquoHIMTrdquo values

In view of the high Na2O content of samples 3-3 and 6-3(Table 4) 18O enrichment may be explained by remelting ofprevious glass with addition of further amounts of natron asflux which causes an increase in Na2O concentration and inthe 18O content of the final products

Apart from their slightly higher 12057518O values (161 and164permil resp) samples 3-4 and 10-4 show quite differentchemical compositions Sample 3-4 is chemically comparablewith ldquoGroup 2rdquo [22] the chronological diffusion ofwhich alsomatches the age proposed (5th-6th centuries AD) whereassample 10-4 is similar to Roman glass 1stndash3rd centuries Adin age although the presence of Cu and Pb may also indicaterecycling of coloured and opaque glass as in the case ofsample 7-1 Both samplesmay be produced in local secondaryworkshops by recycling previous glass (perhaps from theLevantine area) with the addition of further amounts ofnatron as flux as suggested by their high Na2O content(Table 4) thus increasing the 18Ocontent of the final product

According to its chemical composition sample 13-4(Table 4 12057518O= 173permil) was obtained with soda ash as flux asdeduced from its high K2O MgO and P2O5 contents Wesuggest a different starting material for this sample as in thecase of other soda plant ash glass identified in the Greekassemblage

Lastly sample 8-4 from Thessaloniki has 12057518O of 156permilthat is within the average Roman values suggesting the use ofBelus or Volturno sand and Egyptian natron as rawmaterialsbut its chemical composition is comparable to that of glassproduced with soda plant ash as flux The chronologicaldiffusion of soda ash glass in Europe andMediterranean area[4 41] excludes a Roman age for this sample and chem-ical comparisons with 3rdndash7th-century soda ash glass fromIraq [42 43] where plant ash continued to be used as fluxthroughout the period of natron dominance in the West [4]have not shown any consistency with the present sampleTherefore great uncertainty remains in the case of sample 8-4 as regards both its age and provenance also in view of theheavily enriched oxygen signatures of other soda ash samplesidentified here (Table 4) However sample 8-4 differs fromthe others due to its lower SiO2 (616 wt) and higher Al2O3(390wt) which suggest a different silica source probably asilica sand rich in feldsparsThis source may be characterisedby a less positive oxygen signature probably related to thefeldspars content of the sand which influences the 18Ocontent of the final productThis hypothesis is also supportedby the isotopic and chemical signatures of sample 13-4Obtained again with soda plant ash as flux this sample hasAl2O3 content intermediate between that of sample 8-4 andall other Greek soda ash samples and consequently shows anintermediate 12057518O value

12 Journal of Chemistry

4 Conclusions

The results of the present study emphasize the importanceof measuring the oxygen isotopic and chemical compositionsof glass samples in order to constrain some features such asage raw materials and production technology Comparisonsof our isotopic and chemical data with those reported in theliterature particularly in the case of glass from the Levantinearea are of particular interest as regards the trading ofraw glass to secondary workshops in Greece although forsome samples obtained with soda ash as flux and heavilyenriched in 18O production from local raw materials cannotbe completely excluded

In summary the thirty-nine glass samples from northernGreece studied here have oxygen isotopic compositionswhich allow them to be subdivided into three groups

The first is composed of twenty-nine samples (severalfrom Thessaloniki and all those from Maroneia) with 12057518Ovalues equal or very close to themean value of Roman glassesfrom European and Middle Eastern areas These similaritiesimply their production with raw materials with equal or veryclose oxygen isotopic composition such as sand from therivers Belus in Palestine and Volturno in Italy as suggestedby Pliny the Elder In contrast with the remarkable isotopichomogeneity heterogeneous chemical compositions allowthe subdivision of these samples into several subgroupswhich are compared with major compositional groups iden-tified in the Western Mediterranean during the first millen-nium AD

Seven samples from Thessaloniki and all the samplesfrom Maroneia show chemical similarity with ldquoGroup 2rdquo ofFoy et al [22] while one sample shows chemical simi-larity with HIMT glass Accordingly their age should beconstrained to the late Antique period for the Thessalonikiglass and confirmed for the Maroneia samples (ie 4thndash6thcenturies AD) Nine samples from Thessaloniki are chemi-cally comparable with Roman glass although they differ incolouringdecolouring elements and recycling indicators Inparticular in some samples the identification of manganeseintentionally added as a decolourant allows us to constraintheir age according to the chronological diffusion reported inthe literature of this decolourant that is from the 3rd to 4thcenturies AD Lastly three samples from Thessaloniki(1stndash6th centuries AD) with 12057518O values comparable withldquoRomanrdquo values have chemical compositions very differentfrom ldquotypicalrdquo Roman glass suggesting different productiontechnologies

The second isotopic group is composed of four samplesfrom Thessaloniki showing heavily enriched 12057518O values(205 to 227permil) their chemical analyses indicate that theywere obtained using soda ash as flux which has little effect onthe final oxygen isotopic composition of glass These high12057518O values may be explained by the use of silica rawmaterials with heavy 18O enrichment such as chert which isalso found in the Thessaloniki region Therefore these sam-ples may be the product of local glass factories

The third group is composed of five samples from Thes-saloniki showing moderate 18O enrichment (161 to 186permil)

From the chemical point of view four samples are natronglass with compositions similar to Roman or ldquoweakrdquo HIMTgroups and one is a soda ash glass In the case of natron glassthe moderate 18O enrichment may be obtained by recyclingglass (perhaps from the Levantine area) in local secondaryworkshops with the addition of further amounts of natron asflux as suggested by their high Na2O contents In the case ofsoda ash themoderate 18O enrichment with respect to otherGreek soda ash glass may be due to the use of less positivesilica source

In conclusion these interesting results the first obtainedon glass samples from northern Greece support trades andcommercial exchanges between theNear East andGreece andsuggest although further data are required to confirm it thatthe ldquofingerprintrdquo ofGreek glass production could be related tothe use of local chert and soda ash as possible raw materials

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

The authors are grateful to D Grammenos director ofthe Archaeological Museum of Thessaloniki for providingglass samples from Thessaloniki R Carampin (Istituto diGeoscienze e Georisorse Sezione di Padova CNR) F Gallo(Dipartimento dei Beni Culturali Universita di Padova) andD Pasqual (Dipartimento diGeoscienze Universita di Padova)are thanked for their kind support to execution of chemicalanalyses Financial support was provided by ldquoEx 60rdquo fundsof the University of Padova (principal investigator AlbertaSilvestri)

References

[1] R Newton andD DavisonConservation of Glass Butterworth-Heinemann Oxford UK 1999

[2] R H Brill R N Clayton T K Mayeda and C P StapletonldquoOxygen isotope analyses of early glassesrdquo in Chemical Analysesof Early Glasses R H Brill Ed vol 2 pp 303ndash322 CorningMuseum of Glass New York NY USA 1999

[3] A Silvestri A Longinelli andGMolin ldquo12057518Omeasurements ofarchaeological glass (Roman toModern age) and rawmaterialspossible interpretationrdquo Journal of Archaeological Science vol37 no 3 pp 549ndash560 2010

[4] M S Tite A Shortland Y Maniatis D Kavoussanaki and S AHarris ldquoThe composition of the soda-rich and mixed alkaliplant ashes used in the production of glassrdquo Journal of Archae-ological Science vol 33 no 9 pp 1284ndash1292 2006

[5] C Antonaras ldquoGlass working in Roman and early ChristianThessaloniki older and more recent findsrdquo in Proceedings of theHistory Technology and Conservation of Ancient Metals Glassesand Enamels International Symposium Athens Greece Novem-ber 2011

[6] I Friedman and J R OrsquoNeil ldquoCompilation of stable isotopefractionation factors of geochemical interestrdquo in Data of

Journal of Chemistry 13

Geochemistry Geological Survey Professional Paper 440-KKchapter KK 1977

[7] A Silvestri and A Marcante ldquoThe glass of Nogara (Verona) aldquowindowrdquo on production technology of mid-Medieval times inNorthern Italyrdquo Journal of Archaeological Science vol 38 no 10pp 2509ndash2522 2011

[8] S Alberta M Gianmario and P Valentina ldquoThe stained glasswindow of the southern transept of St Anthonyrsquos Basilica(Padova Italy) study of glasses and grisaille paint layersrdquoSpectrochimica ActamdashPart B Atomic Spectroscopy vol 66 no1 pp 81ndash87 2011

[9] K Govindaraju ldquoCompilation of working values and sampledescription for 383 geostandardsrdquoGeostandards Newsletter vol18 pp 1ndash158 1994

[10] A Savitzky andM J EGolay ldquoSmoothing anddifferentiation ofdata by simplified least squares proceduresrdquo Analytical Chem-istry vol 36 no 8 pp 1627ndash1639 1964

[11] J Henderson J A Evans H J Sloane M J Leng and CDoherty ldquoThe use of oxygen strontium and lead isotopesto provenance ancient glasses in the Middle Eastrdquo Journal ofArchaeological Science vol 32 no 5 pp 665ndash673 2005

[12] K A Leslie I C Freestone D Lowry and M Thirlwall ldquoTheprovenance and technology of Near Eastern glass oxygenisotopes by laser fluorination as a complement to strontiumrdquoArchaeometry vol 48 no 2 pp 253ndash270 2006

[13] R H Brill ldquoScientific investigations of the Jalame glass andrelated findsrdquo in Excavations at Jalame Site of a Glass Factory inLate Roman Palestine G D Wienberg Ed pp 257ndash293University of Missouri Press Columbia Mo USA 1988

[14] M Pomerancblum ldquoThe distribution of heavy minerals andtheir hydraulic equivalents in sediments of the Mediterraneancontinental shelf of Israelrdquo SEPM Journal of SedimentaryResearch vol 36 pp 162ndash174 1966

[15] D J Stanley Y Mart and Y Nir ldquoClay mineral distributions tointerpret Nile cell provenance and dispersal II Coastal plainfrom Nile delta to northern Israelrdquo Journal of Coastal Researchvol 13 no 2 pp 506ndash533 1997

[16] M B Hatzopoulos and L D Loukopoulou Morrylos Centrede Recherches de lrsquoAntiquite Grecque et Romaine AthenesGreece 1989

[17] E Dotsika D Poutoukis I Tzavidopoulos Y Maniatis DIgnatiadou and B Raco ldquoA natron source at Pikrolimni Lake inGreece Geochemical evidencerdquo Journal of Geochemical Explo-ration vol 103 no 2-3 pp 133ndash143 2009

[18] H E Foster and C M Jackson ldquoThe composition of ldquonaturallycolouredrdquo late Roman vessel glass from Britain and the impli-cations for models of glass production and supplyrdquo Journal ofArchaeological Science vol 36 no 2 pp 189ndash204 2009

[19] I C Freestone ldquoAppendix chemical analysis of lsquorawrsquo glass frag-mentsrdquo in Excavations at Carthage Volume II1 The CircularHarbour North SideThe Site and FindsOther than Pottery H RHurst Ed British Academy Monographs in Archaeology N∘4p 290 Oxford University Press Oxford UK 1994

[20] I C Freestone M Ponting and M J Hughes ldquoThe origins ofByzantine glass from Maroni Petrera Cyprusrdquo Archaeometryvol 44 no 2 pp 257ndash272 2002

[21] D C W Sanderson J R Hunter and S E Warren ldquoEnergydispersive X-ray fluorescence analysis of 1stmillennium ad glassfrom Britainrdquo Journal of Archaeological Science vol 11 no 1 pp53ndash69 1984

[22] D Foy M Picon M Vichy and V Thirion-Merle ldquoCar-acterisation des verres de la fin de lrsquoAntiquite en Mediterraneeoccidentale lrsquoemergence de nouveaux courants commerciauxrdquoin Echanges et Commerce du Verre dans le Monde Antique DFoy and M D Nenna Eds Actes du Colloque de lrsquoAssociationFrancaise pour lrsquoArcheologie du Verre Aix-en-Provence etMarseille June 2001 pp 41ndash85 Monique Mergoil MontagnacFrance 2003

[23] D Rosenow and T Rehren ldquoHerding cats Roman to LateAntique glass groups from Bubastis northern Egyptrdquo Journal ofArchaeological Science vol 49 no 1 pp 170ndash184 2014

[24] P Mirti A Casoli and L Appolonia ldquoScientific analysis ofroman glass from augusta praetoriardquo Archaeometry vol 35 no2 pp 225ndash240 1993

[25] A Silvestri G Molin and G Salviulo ldquoRoman and medievalglass from the Italian area bulk characterization and relation-ships with production technologiesrdquo Archaeometry vol 47 no4 pp 797ndash816 2005

[26] A Silvestri S Tonietto and G Molin ldquoThe palaeo-Christianglass mosaic of St Prosdocimus (Padova Italy) archaeometriccharacterisation of lsquogoldrsquo tesseraerdquo Journal of ArchaeologicalScience vol 38 no 12 pp 3402ndash3414 2011

[27] F Gallo and A Silvestri ldquoMedieval glass from Rocca di Asolo(northern italy) an archaeometric studyrdquoArchaeometry vol 54no 6 pp 1023ndash1039 2012

[28] F Gallo A Marcante A Silvestri and G Molin ldquoThe glass ofthe ldquoCasa delle Bestie Feriterdquo a first systematic archaeometricstudy on Late Roman vessels from Aquileiardquo Journal of Archae-ological Science vol 41 pp 7ndash20 2014

[29] S Maltoni T Chinni M Vandini E Cirelli A Silvestri andG Molin ldquoArchaeological and archaeometric study of the glassfinds from the ancient harbour of Classe (Ravenna-Italy) newevidencerdquo Heritage Science vol 3 no 1 article 13 2015

[30] A Ceglia P Cosyns K Nys H Terryn H Thienpont and WMeulebroeck ldquoLate antique glass distribution and consumptionin Cyprus a chemical studyrdquo Journal of Archaeological Sciencevol 61 pp 213ndash222 2015

[31] N Schibille A Sterrett-Krause and I C Freestone ldquoGlassgroups glass supply and recycling in late Roman CarthagerdquoArchaeological and Anthropological Sciences pp 1ndash19 2016

[32] A Cholakova T Rehren and I C Freestone ldquoCompositionalidentification of 6th c AD glass from the Lower DanuberdquoJournal of Archaeological Science Reports vol 7 pp 625ndash6322016

[33] S Conte T Chinni R Arletti and M Vandini ldquoButrint(Albania) between eastern and western Mediterranean glassproduction EMPA and LA-ICP-MS of late antique and earlymedieval findsrdquo Journal of Archaeological Science vol 49 no1 pp 6ndash20 2014

[34] I C Freestone S Wolf and M Thirlwall ldquoThe production ofHIMT glass elemental and isotopic evidencerdquo inAnnales du 16eCongres de lrsquoAssociation Internationale pour lrsquoHistoire du Verre(AIHV rsquo05) pp 153ndash157 London UK 2005

[35] M D Nenna M Picon and M Vichy ldquoAteliers primaries etsecondaries en Egypte a lrsquoepoque greco-romainerdquo in La Routedu Verre Ateliers Primaires et Secondaires du Second Millenaireav J-C au Moyen Age M D Nenna Ed vol 33 pp 97ndash112Travaux de la Maison de lrsquoOrient Mediterraneen 2000

[36] C M Jackson ldquoMaking colourless glass in the Roman periodrdquoArchaeometry vol 47 no 4 pp 763ndash780 2005

[37] E V Sayre ldquoThe intentional use of antimony and manganese inancient glassesrdquo in Advances in Glass Technology Part 2 F R

14 Journal of Chemistry

Matson and G Rindone Eds pp 263ndash282 Plenum Press NewYork NY USA 1963

[38] H E Foster and C M Jackson ldquoThe composition of lateRomano-British colourless vessel glass glass production andconsumptionrdquo Journal of Archaeological Science vol 37 no 12pp 3068ndash3080 2010

[39] J Henderson ldquoThe raw materials of early glass productionrdquoOxford Journal of Archaeology vol 4 no 3 pp 267ndash291 1985

[40] B Gratuze and K Janssens ldquoProvenance analysis of glassartefactsrdquo inNon-Destructive Microanalysis of Cultural HeritageMaterials K Janssens and R Van Grieken Eds pp 663ndash712Elsevier Amsterdam The Netherlands 2004

[41] J Henderson ldquoTradition and experiment in first millenniumAD glass productionmdashthe emergence of early Islamic glasstechnology in late antiquityrdquoAccounts of Chemical Research vol35 no 8 pp 594ndash602 2002

[42] P Mirti M Pace M M Negro Ponzi and M Aceto ldquoICP-MSanalysis of glass fragments of Parthian and Sasanian epoch fromSeleucia and Veh Ardasır (Central Iraq)rdquoArchaeometry vol 50no 3 pp 429ndash450 2008

[43] P Mirti M Pace M Malandrino and M N Ponzi ldquoSasanianglass from Veh Ardasır new evidences by ICP-MS analysisrdquoJournal of Archaeological Science vol 36 no 4 pp 1061ndash10692009

[44] J Hoefs Stable Isotope Geochemistry Springer Berlin Ger-many 5th edition 2004

[45] A Silvestri G Molin and G Salviulo ldquoThe colourless glass ofIulia Felixrdquo Journal of Archaeological Science vol 35 no 2 pp331ndash341 2008

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 201

International Journal ofInternational Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal ofInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

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Analytical Methods in Chemistry

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Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

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The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Journal of

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Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Journal of Chemistry 5

Table 3 Isotopic and chemical composition of glasses fromMaroneia 4thndash6th centuries AD in age Note that CoO NiO CuO ZnO SnO2Sb2O3 and PbO contents are not reported because they are lower than EMPA detection limits for all samples (LOD of CoO NiO and CuO =003 wt LOD of ZnO SnO2 Sb2O3 = 004 wt LOD of PbO = 008 wt)

Sample 12057518O SiO2 Na2O CaO Al2O3 K2O MgO FeO TiO2 MnO P2O5 SO3 ClNumber (VSMOW) Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt1-2 154 6711 1739 784 229 061 110 106 015 154 007 030 1022-2 155 6623 1780 783 270 076 123 133 017 123 015 031 0923-2 156 6462 1770 898 240 072 147 104 016 182 012 034 0924-2 159 6564 1846 795 270 082 121 138 016 096 013 032 0915-2 156 6570 1738 825 238 059 121 088 015 169 009 034 0956-2 156 6679 1717 750 253 060 125 098 016 184 008 030 1007-2 157 6463 1796 907 257 071 150 110 018 172 013 033 0928-2 152 6556 1756 752 250 065 125 093 017 234 009 029 1019-2 160 6613 1814 783 273 084 122 128 015 099 016 034 09010-2 153 6659 1636 859 240 069 111 088 017 160 011 036 087

156 plusmn 02permilmean isotopic composition

Table 4 Isotopic and chemical composition of Roman and late Antique glasses from Thessaloniki 1stndash6th centuries AD in age Sampleswith moderate and strong 18O enrichment are in italics and bold font respectively Note that NiO ZnO and SnO2 contents are not reportedbecause they are lower than EMPA detection limits for all samples (LOD of NiO = 003wt LOD of ZnO and SnO2 = 004wt)

Sample 12057518O SiO2 Na2O CaO Al2O3 K2O MgO FeO TiO2 MnO P2O5 SO3 Cl CoO CuO Sb2O3 PbONumber (VSMOW) Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt Wt1-3 226 6746 1300 974 117 485 201 058 006 096 069 007 128 lt003 lt003 lt004 lt0082-3 225 6731 1320 980 115 477 200 057 005 096 066 007 129 lt003 lt003 lt004 lt0083-3 186 6695 1946 671 221 043 096 063 010 127 010 025 143 lt003 lt003 lt004 lt0084-3 158 6420 1767 702 285 040 128 212 037 265 010 040 123 lt003 lt003 lt004 lt0085-3 156 6789 1617 864 268 053 083 044 007 136 007 035 119 lt003 lt003 lt004 lt0086-3 173 6492 1919 821 232 059 106 094 014 158 007 045 087 lt003 lt003 lt004 lt0087-3 152 7162 1553 647 263 065 042 026 004 033 009 003 106 lt003 lt003 lt004 lt0083-4 161 6478 1862 775 237 059 119 115 015 152 005 044 093 lt003 lt003 lt004 lt0084-4 153 6732 1696 785 252 031 088 072 022 161 001 028 136 lt003 lt003 lt004 lt0085-4 153 6678 1796 652 240 050 095 079 021 166 002 029 119 lt003 lt003 lt004 lt0086-4 153 6525 1746 783 246 062 100 080 015 192 005 047 099 lt003 lt003 004 lt0087-4 153 6580 1876 630 189 054 087 067 010 077 004 031 146 lt003 178 lt004 lt0088-4 156 6156 1248 1003 390 495 193 079 017 073 043 014 088 lt003 lt003 004 0509-4 227 6780 980 921 110 545 235 051 005 067 052 010 091 lt003 lt003 004 lt00810-4 164 6546 1983 636 248 049 116 117 016 011 001 052 123 004 021 lt004 06311-4 154 6451 1791 864 265 076 118 143 014 066 011 045 098 lt003 lt003 lt004 lt00812-4 205 6272 1179 945 134 440 204 092 006 438 039 013 105 lt003 lt003 006 lt00813-4 173 6444 1268 964 234 423 207 076 012 121 042 016 101 lt003 lt003 004 01414-4 156 6448 1781 723 258 079 134 197 015 115 014 054 098 lt003 lt003 lt004 lt008

Na2O CaO K2O and MgO contents with the previousglass samples although they differ in contents of colour-ingdecolouring elements for example iron copper man-ganese and antimony and minor elements for example tinand lead (Tables 2 and 4) In particular samples 5-3 4-4 and5-4 show concentrations of manganese higher than 1 wtwhereas sample 6-1 has nomanganese but antimony (Table 2)Instead samples 3-1 and 7-3 do not reveal any manganeseor antimony (Tables 2 and 4) Sample 2-1 from ThessalonikiAgora has relatively high concentrations of CuO SnO2 PbO

and P2O5 (Table 2) The chemical composition of sample7-1 is comparable with that of sample 2-1 except for thelower copper and lead contents (Table 2) Lastly samples 4-1 and 10-1 from Thessaloniki Agora which have comparable12057518Ovalues show chemical compositions different from eachother except for the similar (and relatively low) content ofsodium (about 10 wt Na2O) and the absence of manganeseand trace elements in both samples In particular sample 4-1has lower SiO2 and CaO and higher Al2O3 K2O MgO FeOP2O5 and Cl than sample 10-1 (Table 2)

6 Journal of Chemistry

Table 5 12057518O(VSMOW) of chert samples from the quarries in Triadiof Thessaloniki (Central Macedonia Greece)

Samples 12057518O(VSMOW) MeanTrd 1-1 250 251 250Trd 1-2 234 235 234Trd 1-4 236 238 237Trd 1-5 260 261 260Trd 2-1 242 244 243Trd 3-1 261 260 260Trd 3-2 258 260 259Trd 5-2 225 223 224

Mean value 246 plusmn 14permil

Lastly sample 8-4 fromThessaloniki with 12057518O equal to156permil is characterised by lower silicium and sodium con-tents and higher calcium aluminium potassium magne-sium and phosphorous contents (Table 4) than other glasseswith comparable isotopic composition

In addition to samples with isotopic signatures rangingfrom 152 to 160permil the isotopic data indicate that foursamples fromThessaloniki are heavily enriched by about 7permilsample 12-4 has 12057518O equal to 205permil and samples 1-3 2-3and 9-4 have values from 225 to 227permil Finally other fivesamples fromThessaloniki (3-3 6-3 3-4 10-4 and 13-4) showmoderate 18O enrichment with values between 161 and186permil (Table 4)

The chemical analyses of the heavily enriched glass(Table 4) show that all samples are characterised by higherCaO K2O MgO and P2O5 and lower Na2O and Al2O3contents than other Greek samples with lower isotopic com-position In addition sample 12-4 also has exceptionally highmanganese (MnO = 438wt Table 4)

The samples with moderate 18O enrichment show quitevariable chemical compositions but comparable to those ofsamples with lower and higher isotopic compositions Sam-ples 3-3 (12057518O= 186permil) and 10-4 (12057518O= 164permil) have chem-ical compositions comparable to those of samples 5-3 4-4and 5-4 although sample 10-4 has very little Mn and highCu and Pb (Table 4) Sample 6-3 (12057518O = 173permil) is similarin chemical composition to samples 1-1 5-1 8-1 91 4-3 6-4 11-4 and 14-4 from Thessaloniki (Tables 2 and 4) and allthe samples from Maroneia (Table 3) Finally the chemicalcomposition of sample 13-4 (12057518O = 173permil) is very similar tothose of the heavily enriched glass as deduced from itslow Na2O and Al2O3 and high CaO K2O MgO and P2O5contents (Table 4)

The isotopic data obtained on the chert samples from thequarries in Triadi ofThessaloniki show that mean 12057518O value(equal to 246 plusmn 14permil Table 5) is comparable to those ofGreek glass samples heavily enriched (mean 12057518O value =221 plusmn 11permil) Mineralogical data obtained by means ofXRPD show chert samples are a mixture of quartz andgoethite (semiquantitative contents of the two phases 94quartz and 6 goethite) except for sample Trd 1-5 composedof only quartz (Figure 1)

XRF data furtherly confirm the mineralogical composi-tions sample Trd 1-2 being almost entirely composed of SiO2and Fe2O3 and Trd 1-5 of only SiO2 (Table 6)

32 Discussion The majority of the analysed samples fromThessaloniki and all the samples from Maroneia have ahomogeneous oxygen isotopic composition (12057518O value =156 plusmn 025permil Table 2 and Figure 2) which is equal orvery close to the mean value of ldquoRomanrdquo glass as deducedfrom a set of isotopic measurements on glass from Europedated from the 1st to the 4th centuries AD which show arelatively narrow range of 12057518O (from about 154permil to 160permil)[2 3] Similar results (Figure 2) were also obtained for lateAntiqueearly Medieval samples from Grado and Vicenzatwo sites in Northern Italy [3] and for coeval glass from theNear East [11 12]

These similarities may be explained by assuming thatthe Greek glass samples were produced with raw materialswith equal or very similar oxygen isotopic compositionSand from the rivers Belus in Palestine and Volturno inItaly mentioned by Pliny the Elder in Naturalis Historia asmaterials for making glass is suitable for glass productionand has the same oxygen isotopic composition when theVolturno sandundergoes selective grinding [3] It follows thatglass produced with either Belus or Volturno sand as networkformer and natron as flux is practically indistinguishablefrom the oxygen isotopic point of view Consequently theisotopic composition of most of the Greek samples in Tables2 3 and 4 cannot help to distinguish among glass samplesimported from Italy or the Near East or glass samplesproduced inGreek secondary glassworkshops bymelting rawglass from the geographic point of view a Levantine originfor the Greek glass samples is quite reasonable This origin isreinforced by data reported in Brill [13] on five cullets froman ancient glass workshop at Jalame in western Galilee (3rd-4th centuries AD) The author suggests that the silica usedfor these cullets came from sand taken from the mouth ofthe Belus and that the oxygen isotopic composition of quartzwas enriched in 18O by the calcium carbonate contained inthe sand in the form of sea shells with natron as flux The12057518O values of the Jalame glass are slightly lower than thoseof Greek samples and range from about 14 to 15permil (Figure 2)Although the use of various other raw materials cannot becompletely excluded this small difference may be explainedby amounts of natron used for melting which are slightlysmaller in Jalame than in Greek glass samples The oxygenisotopic study carried out by Silvestri et al [3] on Romannatron glass demonstrated the ldquopositive natron effectrdquo that isit is presumed that flux which has very positive 12057518O valuescaused 18O enrichment in the final glass as confirmed bythe plot of Na2O versus 12057518O which clearly shows a positivecorrelation Other glass samples from the Near East have12057518O values close to those of our samples showing ldquoRomanrdquovalues (Figure 2) These samples measured by Leslie et al[12] came from different locations three from the BethShersquoan in Israel (6th-7th centuries AD) mean value 146permilthree from Tel el-Ashmunein in Egypt (8th-9th centuries)mean value 148permil and three from Carthage in Tunisia

Journal of Chemistry 7

10 20 30 40 50 60 70

Cou

nts

0

TRD-1-2

Peak list

Goethite syn FeO(OH)

50000

100000

150000

Quartz low SiO2

Position (∘2휃) (copper (Cu))

(a)

TRD-1-5

10 20 30 40 50 60 70

Cou

nts

Peak list

0

100000

200000

Quartz low SiO2

Position (∘2휃) (copper (Cu))

(b)

Figure 1 XRPD patterns of chert samples named Trd 1-2 (a) and Trd 1-5 (b) representative of the twomineralogical compositions identified

(4thndash6th centuries) mean value 150permil All these samplesare obtained using natron from the evaporitic lakes of WadiNatron in Egypt The provenance of sand from a relativelyshort stretch of the eastern Mediterranean coast is suggestedfor the Beth Shersquoan samples and the similarity between thedelta values of the Tel el-Ashmunein and Carthage samplesis explained by their production with the same Egyptiansand The isotopic similarity among these three groups ofsamples can be explained taking into account a commonprovenance for natron and that Levantine sand comes fromEgypt and is transported up to the eastern Mediterraneancoast by sea currents [14 15] therefore the use of sandand flux with similar provenance yields glass samples withsimilar isotopic compositions The same source may thusbe hypothesised for the Greek glass samples analysed hereHowever it should be stressed that natural natron depositsin the region of Macedonia in northern Greece were well-known in the time of Plato (5th century BC) and werealso described by Pliny the Elder in his Naturalis HistoriaeHatzopoulos and Loukopoulou [16] identified Lake Chalastra(so-called in antiquity that is the place where the ldquoCha-lastraion nitronrdquo formed and dissolved over a period of afew days) as the modern lake of Picrolimni located about20 km NW of Thessaloniki The geochemical conditionsresponsible for the formation of ldquoChalastraion nitronrdquo haverecently been studied and discussed by Dotsika et al [17]The salts deposited by the lake brine were mineralogicallyidentified by XRD analysis and include not only calcite anddolomite but also trona (Na2CO3sdotNaHCO3sdot2H2O) burkeite(Na2CO3sdot2Na2SO4) and halite (NaCl) thus confirming themineralogical similarity between these deposits and thosefrom Wadi Natron in Egypt However the oxygen isotopiccompositions determined on the Picrolimni salt deposits

range from about 11 to 25permil (VSMOW) much lower than thevalues for Wadi Natron (about 34 to 40permil [2 3]) Thereforein the case of our samples use of ldquoChalastraion nitronrdquo as fluxcan hardly be considered

In contrast with the remarkable isotopic homogeneity ofthe majority of Greek samples (2939 samples) the chemicalcomposition is rather heterogeneous (Tables 2 3 and 4)although they are all obtainedwith natron as flux having bothK2O and MgO contents lower than 15 wt In particularsamples 1-1 5-1 8-1 9-1 4-3 6-4 11-4 and 14-4 fromThessaloniki (Tables 2 and 4) and all the samples fromMaroneia (Table 3) show the HIMT (High Iron Magnesiumand Titanium) signature This reference group is defined byhigh levels of iron (ge07 wt)manganese (usually sim1-2 wt)magnesium (usuallyge08 wt) and titanium (ge01 wt) andits yellow-green colour is due to the amount of iron sugges-tive of a relatively impure sand source [18] These also are thekey characteristics of Greek glass samples which have highFeO (120 plusmn 031wt) MnO (154 plusmn 035wt) MgO (124 plusmn016wt) and TiO2 (018plusmn005wt) contentsThe acronymHIMT was first applied by Freestone [19] to raw glass fromCarthage and glass vessels from Cyprus [20] although glasswith high contents of iron manganese and titanium wasalready identified by Sanderson et al [21] However all theGreek samples (except 4-3) containing about 50ndash60 of theamount of iron titanium and manganese oxides measuredin ldquotypicalrdquo HIMT glass such as Group 1 of Foy et al [22](about 121 plusmn 031wt as FeO 017 plusmn 003wt as TiO2and 151 plusmn 037wt as MnO versus 2 plusmn 08wt as FeO05 plusmn 01wt as TiO2 and 22 plusmn 04wt as MnO for Greeksamples and Group 1 resp) show a better fit with ldquoGroup 2rdquoof Foy et al [22] whichmay be considered as a ldquoweakrdquo HIMTglass [18] due to lower contents of the key oxides of HIMT

8 Journal of Chemistry

Table6Ch

emicalcompo

sitions

ofchertsam

plesn

amed

Trd1-2

andTrd1-5

representativeof

thetwomineralogicalcompo

sitions

identifi

ed(X

RFdataL

OIlosson

ignitio

n)N

otethat

GaYNbLaC

eandUcontentsaren

otrepo

rted

becausetheyarelow

erthan

XRFdetectionlim

itsfora

llsamples

(LODof

Ga=

5ppm

LODof

YNbandU=3p

pmLODof

LaandCe=

10pp

m)

Sample

SiO2

TiO2

Al 2O3

Fe2O3

MnO

MgO

CaO

Na 2O

K 2O

P 2O5

LOI

ScV

CrCo

Ni

CuZn

RbSr

ZrBa

Nd

PbTh

Num

berWt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

Trd1-2

9068

001

021

713

015

037

012

005

001

002

218

9314

507

124

146

1846

78

920

1912

7Trd1-5

9998lt00

05lt00

2lt00

05lt00

05lt00

2lt00

05lt00

2lt00

05lt00

05000lt3lt3lt3lt3lt3lt3lt3lt3lt3lt3lt10lt10lt10lt3

Journal of Chemistry 9

10 11 42 10 9 5 9 16 414

15

16

17

18

19

Number of samples

훿18O

(VSM

OW

)(permil

)

Figure 2 Comparisons among 12057518O(VSMOW) values of natron glasssamples [open symbols Thessaloniki Agora (◻) Maroneia ()Thessaloniki various sites (998779)Thessaloniki glass withmoderate 18Oenrichment (I)] and those already reported in the literature [fullsymbols Roman glass from Europe (◼) [2] Roman glass from IuliaFelix (X) [3] 4th century AD glass from Jalame (998771) [2] HIMTglass from Carthage and Levantine natron glass (bold plus sign)[12] late Antique-earlyMedieval glass fromGrado ad Vicenza (boldmultiplication sign) [3]] Number of analysed samples is also shown

glass (Figure 3) Instead sample 4-3 has FeO TiO2 andMnO contents (Table 4) perfectly comparable with ldquotypicalrdquoHIMT glass [18 22] In general HIMT glass has also beenidentified in Britain [18] Egypt [23] France [22] Italy [24ndash29] Cyprus [20 30] Carthage [31] Bulgaria [32] andAlbania[33] The chemical and isotopic signatures of HIMT glass aresuggestive of continental sand sources of high maturity richin heavy minerals and located in the Near East probablyin Egypt [12 31 34] As regards the dating of the referencegroups in general terms the HIMT group is probably morecharacteristic of the period from the mid-4th century ADonwards although according to current research its compo-sition seems to have continued after the 5th century [18]In addition according to Schibille et al [31] ldquoGroup 2rdquo isdated to the 5th-6th centuries and is thus coeval with theglass from Maroneia Consequently the age of Thessalonikiglass samples similar in composition to those of ldquoGroup 2rdquois constrained to the late Antique period

The other glass samples from Thessaloniki (2-1 3-1 6-17-1 5-3 7-3 4-4 5-4 and 7-4) whose 12057518O is in therange of ldquoRomanrdquo values also show the chemical compo-sition typical of Roman glass [35] although they differ incontents of manganese and antimony (Figure 3) and traceelements In particular samples 3-1 5-3 4-4 and 5-4 showMnO gt 05 wt which suggests its intentional addition asa decolouriser [36] whereas sample 6-1 has no manganesebut antimony (Table 2) As these two elements the principal

decolourisers used between the 1st and 4th centuries ADwere both predominant from the late 1st to the 3rd centuriesand as the use of manganese increased from the end of the3rd to the 4th century [36ndash38] the age of these samples isconstrained accordingly Instead samples 3-1 and 7-3 do notreveal any intentional addition of decolouriser having noantimony and MnO lt 05 wt (Tables 2 and 4) Sample 2-1from Thessaloniki Agora has relatively high concentrationsof CuO SnO2 PbO and P2O5 (Table 2) suggesting theinclusion of cullet perhaps coloured and opaque mosaictesserae containing high quantities of one or more of theseelements in the glass batch The chemical composition ofsample 7-1 is not far from that of sample 2-1 although the con-centrations of copper and lead are much lower than those insample 2-1 (Table 2) This indicates that the presence ofthe above elements is due to recycling of earlier colouredglass because they occur in concentrations higher than thoseattributable to impurities in the raw materials but too low tohave any technological significance [39] Conversely the highCu in sample 7-4 not associated with high Sn Co Pb Sband Zn (Table 4) suggests that this element was intentionallyadded to produce the aquamarine colour

Lastly chemical similarities between samples 4-1 and 10-1from Thessaloniki Agora and data reported in the literatureare difficult to establish Sample 4-1 seems quite comparablewith some soda-potash-lime glass from the 14th-centuryworkshop at Saint-Chely (France) Two different hypothesesboth equally valid from an analytical point of view are pro-posed to explain the peculiar chemical composition of theseLate Medieval French samples [40] both soda and potashash were used by the glass-workers soda ash remaining themain component recycled glass from the surrounding areaswith both potash and soda ash compositions was used asrawmaterials Sample 10-1 also approaches although not per-fectly the composition of ldquomixed soda-potash glassrdquo dated toLate Bronze age [40] and the oxygen isotopic data obtained byBrill et al [2] on some Late Bronze age objects are also quitecomparable with that of sample 10-1 On the contrary oxygenisotope data on samples with chemical composition similarto sample 4-1 are unfortunately still lacking although dataon Medieval soda ash and late Medieval and modern potashash glass are systematically lower and range from about 12to 145permil [2 3] In any case both isotopic and chemical datasuggest that the age proposed for samples 4-1 and 10-1 fromThessaloniki Agora should be revised

The chemical analyses of the heavily enriched glass(Table 4) show that all samples were melted with soda ashas flux their K2O MgO and P2O5 contents being higherthan those of the other samples (Figure 3) The low Al2O3content suggests that as well as flux a different silica sourcewas used to produce these samples Leslie et al [12] reportsome highly variable isotopic results from glass samples10thndash13th centuries in age from Rarsquos al-Hadd (Oman) one ofwhich is close to 20permil (Figure 4) Heavily enriched 12057518Ovalues which range from 216 to 226permil have already beenmeasured by Brill et al [2] on glass samples from Nimrud(Iraq) dated to the 7th century BC the author obviouslyconcluded that ldquothese glasses must represent a glassmaking

10 Journal of Chemistry

60 64 68 72 76 808

12

16

20N

a 2O

(wt

)

SiO2 (wt)

(a)

0 2 4 6

Natron

Soda plant ash

0

1

2

3

4

MgO

(wt

)

K2O (wt)

(b)

4 6 8 10 120

1

2

3

4

Al 2O

3 (w

t)

CaO (wt)

(c)

0 05 1 15 2 250

1

2

3

4

5

MnO

(wt

)

FeO (wt)

(d)

Figure 3 Na2O versus SiO2 (a) MgO versus K2O (b) Al2O3 versus CaO (c) and MnO versus FeO (d) contents of Greek glass samplessubdivided by provenance Thessaloniki Agora () Maroneia (I) Thessaloniki various sites (998779 natron glass 998771 soda ash glass) Meanchemical compositions and standard deviations of main compositional natron groups identified in literature and comparable with Greeksamples are also shown ldquoRomanrdquo glass (bold plus sign) Group 2 (bold multiplication sign) [22 35]

tradition thatmade use of some particular rawmaterialrdquo Twosamples from Aphrodisias (Turkey) 6th-7th centuries ADin age also yielded 12057518O values of about 234permil (Figure 4)All the samples reported in the literature with very positive12057518O values were obtained with soda ash as flux althoughthey show lowerK2OMgOandhigherNa2OK2Oratios thanGreek samples suggesting the use of different kinds of plantash

In Europe and Mediterranean area soda ash glass datesfrom the 9th century AD onwards [4 41] This wouldexclude a Roman age for Greek soda ash samples unlessthey were produced with raw glass imported from areas suchas Mesopotamia and Iran where plant ash continued to beused as flux in glass production throughout the period ofnatron dominance in the West [4] However so far chemicalcomparisons with 3rdndash7th-century soda ash glass from Iraq

Journal of Chemistry 11

7 6 2 8 6

12

16

20

24훿18O

(VSM

OW

)(permil

)

Number of samples

Figure 4 Comparisons among 12057518O(VSMOW) values of plant ash glasssamples [open symbols Thessaloniki various sites (◻)] and thosealready reported in the literature [full symbols glass from Nimrudand Aphrodisias (◼) [2] glass from Rarsquos al-Hadd (e) and Levantinesoda ash glass (X) [12] Medieval soda ash glass from Italy (998771) [3]]Number of analysed samples is also shown

[42 43] have not shown any consistency with Greek samplesIn addition the heavily enriched 12057518O values do indicatethat their raw materials differed from those normally used inRoman andMedieval glass production and this wouldmatchthe possibility of the different origin of these materials Theuse of ash as flux may cause some 18O enrichment when theash is particularly rich in carbonate bicarbonate and hydrate[4] but hardly to this extent Previous oxygen isotopic dataobtained on Medieval soda ash glass from the Western andEastern Mediterranean (Figure 4) indicate that the additionof ash did not contribute to isotopically heavy oxygen and the12057518Ovalues essentially reflect the silica source (eg [2 3 12])In the case of Greek heavily enriched glass the silica source isdifficult to identify taking into account the fact that quartzwith anomalously heavy isotopic composition is uncommoninmagmatic sedimentary or metamorphic rocks Due to thelarge oxygen isotopic fractionation between SiO2 andwater atlow temperatures biogenic silica and chert have the highest18O16O ratios observed in rocks [44] Therefore the Greeksamples with high isotopic values may be the product oflocal glass workshops which used raw materials composedof chert with the addition of ash probably obtained fromvarious plant species other than those considered by Titeet al [4] or differently pretreated The isotopic chemicaland mineralogical data obtained on a selection of chertsamples from the quarries in Triadi of Thessaloniki (CentralMacedonia Greece) furtherly support the hypothesis of localproduction at least if we consider sample Trd 1-5 composedof only quartz

In the case of samples with moderate 18O enrichmentseveral causes must be considered to explain their valuesSample 3-3 (12057518O= 186permil) has a chemical composition quiteclose to that of Roman glass decolourised by the addition ofMn [45] sample 6-3 (12057518O= 173permil) is chemically comparableto ldquoGroup 2rdquo of Foy et al [22] and its suggested age (6thcentury AD) matches the chronological diffusion of the ref-erence group However both samples have 12057518O higher thanthe average ldquoRomanrdquo or ldquoHIMTrdquo values

In view of the high Na2O content of samples 3-3 and 6-3(Table 4) 18O enrichment may be explained by remelting ofprevious glass with addition of further amounts of natron asflux which causes an increase in Na2O concentration and inthe 18O content of the final products

Apart from their slightly higher 12057518O values (161 and164permil resp) samples 3-4 and 10-4 show quite differentchemical compositions Sample 3-4 is chemically comparablewith ldquoGroup 2rdquo [22] the chronological diffusion ofwhich alsomatches the age proposed (5th-6th centuries AD) whereassample 10-4 is similar to Roman glass 1stndash3rd centuries Adin age although the presence of Cu and Pb may also indicaterecycling of coloured and opaque glass as in the case ofsample 7-1 Both samplesmay be produced in local secondaryworkshops by recycling previous glass (perhaps from theLevantine area) with the addition of further amounts ofnatron as flux as suggested by their high Na2O content(Table 4) thus increasing the 18Ocontent of the final product

According to its chemical composition sample 13-4(Table 4 12057518O= 173permil) was obtained with soda ash as flux asdeduced from its high K2O MgO and P2O5 contents Wesuggest a different starting material for this sample as in thecase of other soda plant ash glass identified in the Greekassemblage

Lastly sample 8-4 from Thessaloniki has 12057518O of 156permilthat is within the average Roman values suggesting the use ofBelus or Volturno sand and Egyptian natron as rawmaterialsbut its chemical composition is comparable to that of glassproduced with soda plant ash as flux The chronologicaldiffusion of soda ash glass in Europe andMediterranean area[4 41] excludes a Roman age for this sample and chem-ical comparisons with 3rdndash7th-century soda ash glass fromIraq [42 43] where plant ash continued to be used as fluxthroughout the period of natron dominance in the West [4]have not shown any consistency with the present sampleTherefore great uncertainty remains in the case of sample 8-4 as regards both its age and provenance also in view of theheavily enriched oxygen signatures of other soda ash samplesidentified here (Table 4) However sample 8-4 differs fromthe others due to its lower SiO2 (616 wt) and higher Al2O3(390wt) which suggest a different silica source probably asilica sand rich in feldsparsThis source may be characterisedby a less positive oxygen signature probably related to thefeldspars content of the sand which influences the 18Ocontent of the final productThis hypothesis is also supportedby the isotopic and chemical signatures of sample 13-4Obtained again with soda plant ash as flux this sample hasAl2O3 content intermediate between that of sample 8-4 andall other Greek soda ash samples and consequently shows anintermediate 12057518O value

12 Journal of Chemistry

4 Conclusions

The results of the present study emphasize the importanceof measuring the oxygen isotopic and chemical compositionsof glass samples in order to constrain some features such asage raw materials and production technology Comparisonsof our isotopic and chemical data with those reported in theliterature particularly in the case of glass from the Levantinearea are of particular interest as regards the trading ofraw glass to secondary workshops in Greece although forsome samples obtained with soda ash as flux and heavilyenriched in 18O production from local raw materials cannotbe completely excluded

In summary the thirty-nine glass samples from northernGreece studied here have oxygen isotopic compositionswhich allow them to be subdivided into three groups

The first is composed of twenty-nine samples (severalfrom Thessaloniki and all those from Maroneia) with 12057518Ovalues equal or very close to themean value of Roman glassesfrom European and Middle Eastern areas These similaritiesimply their production with raw materials with equal or veryclose oxygen isotopic composition such as sand from therivers Belus in Palestine and Volturno in Italy as suggestedby Pliny the Elder In contrast with the remarkable isotopichomogeneity heterogeneous chemical compositions allowthe subdivision of these samples into several subgroupswhich are compared with major compositional groups iden-tified in the Western Mediterranean during the first millen-nium AD

Seven samples from Thessaloniki and all the samplesfrom Maroneia show chemical similarity with ldquoGroup 2rdquo ofFoy et al [22] while one sample shows chemical simi-larity with HIMT glass Accordingly their age should beconstrained to the late Antique period for the Thessalonikiglass and confirmed for the Maroneia samples (ie 4thndash6thcenturies AD) Nine samples from Thessaloniki are chemi-cally comparable with Roman glass although they differ incolouringdecolouring elements and recycling indicators Inparticular in some samples the identification of manganeseintentionally added as a decolourant allows us to constraintheir age according to the chronological diffusion reported inthe literature of this decolourant that is from the 3rd to 4thcenturies AD Lastly three samples from Thessaloniki(1stndash6th centuries AD) with 12057518O values comparable withldquoRomanrdquo values have chemical compositions very differentfrom ldquotypicalrdquo Roman glass suggesting different productiontechnologies

The second isotopic group is composed of four samplesfrom Thessaloniki showing heavily enriched 12057518O values(205 to 227permil) their chemical analyses indicate that theywere obtained using soda ash as flux which has little effect onthe final oxygen isotopic composition of glass These high12057518O values may be explained by the use of silica rawmaterials with heavy 18O enrichment such as chert which isalso found in the Thessaloniki region Therefore these sam-ples may be the product of local glass factories

The third group is composed of five samples from Thes-saloniki showing moderate 18O enrichment (161 to 186permil)

From the chemical point of view four samples are natronglass with compositions similar to Roman or ldquoweakrdquo HIMTgroups and one is a soda ash glass In the case of natron glassthe moderate 18O enrichment may be obtained by recyclingglass (perhaps from the Levantine area) in local secondaryworkshops with the addition of further amounts of natron asflux as suggested by their high Na2O contents In the case ofsoda ash themoderate 18O enrichment with respect to otherGreek soda ash glass may be due to the use of less positivesilica source

In conclusion these interesting results the first obtainedon glass samples from northern Greece support trades andcommercial exchanges between theNear East andGreece andsuggest although further data are required to confirm it thatthe ldquofingerprintrdquo ofGreek glass production could be related tothe use of local chert and soda ash as possible raw materials

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

The authors are grateful to D Grammenos director ofthe Archaeological Museum of Thessaloniki for providingglass samples from Thessaloniki R Carampin (Istituto diGeoscienze e Georisorse Sezione di Padova CNR) F Gallo(Dipartimento dei Beni Culturali Universita di Padova) andD Pasqual (Dipartimento diGeoscienze Universita di Padova)are thanked for their kind support to execution of chemicalanalyses Financial support was provided by ldquoEx 60rdquo fundsof the University of Padova (principal investigator AlbertaSilvestri)

References

[1] R Newton andD DavisonConservation of Glass Butterworth-Heinemann Oxford UK 1999

[2] R H Brill R N Clayton T K Mayeda and C P StapletonldquoOxygen isotope analyses of early glassesrdquo in Chemical Analysesof Early Glasses R H Brill Ed vol 2 pp 303ndash322 CorningMuseum of Glass New York NY USA 1999

[3] A Silvestri A Longinelli andGMolin ldquo12057518Omeasurements ofarchaeological glass (Roman toModern age) and rawmaterialspossible interpretationrdquo Journal of Archaeological Science vol37 no 3 pp 549ndash560 2010

[4] M S Tite A Shortland Y Maniatis D Kavoussanaki and S AHarris ldquoThe composition of the soda-rich and mixed alkaliplant ashes used in the production of glassrdquo Journal of Archae-ological Science vol 33 no 9 pp 1284ndash1292 2006

[5] C Antonaras ldquoGlass working in Roman and early ChristianThessaloniki older and more recent findsrdquo in Proceedings of theHistory Technology and Conservation of Ancient Metals Glassesand Enamels International Symposium Athens Greece Novem-ber 2011

[6] I Friedman and J R OrsquoNeil ldquoCompilation of stable isotopefractionation factors of geochemical interestrdquo in Data of

Journal of Chemistry 13

Geochemistry Geological Survey Professional Paper 440-KKchapter KK 1977

[7] A Silvestri and A Marcante ldquoThe glass of Nogara (Verona) aldquowindowrdquo on production technology of mid-Medieval times inNorthern Italyrdquo Journal of Archaeological Science vol 38 no 10pp 2509ndash2522 2011

[8] S Alberta M Gianmario and P Valentina ldquoThe stained glasswindow of the southern transept of St Anthonyrsquos Basilica(Padova Italy) study of glasses and grisaille paint layersrdquoSpectrochimica ActamdashPart B Atomic Spectroscopy vol 66 no1 pp 81ndash87 2011

[9] K Govindaraju ldquoCompilation of working values and sampledescription for 383 geostandardsrdquoGeostandards Newsletter vol18 pp 1ndash158 1994

[10] A Savitzky andM J EGolay ldquoSmoothing anddifferentiation ofdata by simplified least squares proceduresrdquo Analytical Chem-istry vol 36 no 8 pp 1627ndash1639 1964

[11] J Henderson J A Evans H J Sloane M J Leng and CDoherty ldquoThe use of oxygen strontium and lead isotopesto provenance ancient glasses in the Middle Eastrdquo Journal ofArchaeological Science vol 32 no 5 pp 665ndash673 2005

[12] K A Leslie I C Freestone D Lowry and M Thirlwall ldquoTheprovenance and technology of Near Eastern glass oxygenisotopes by laser fluorination as a complement to strontiumrdquoArchaeometry vol 48 no 2 pp 253ndash270 2006

[13] R H Brill ldquoScientific investigations of the Jalame glass andrelated findsrdquo in Excavations at Jalame Site of a Glass Factory inLate Roman Palestine G D Wienberg Ed pp 257ndash293University of Missouri Press Columbia Mo USA 1988

[14] M Pomerancblum ldquoThe distribution of heavy minerals andtheir hydraulic equivalents in sediments of the Mediterraneancontinental shelf of Israelrdquo SEPM Journal of SedimentaryResearch vol 36 pp 162ndash174 1966

[15] D J Stanley Y Mart and Y Nir ldquoClay mineral distributions tointerpret Nile cell provenance and dispersal II Coastal plainfrom Nile delta to northern Israelrdquo Journal of Coastal Researchvol 13 no 2 pp 506ndash533 1997

[16] M B Hatzopoulos and L D Loukopoulou Morrylos Centrede Recherches de lrsquoAntiquite Grecque et Romaine AthenesGreece 1989

[17] E Dotsika D Poutoukis I Tzavidopoulos Y Maniatis DIgnatiadou and B Raco ldquoA natron source at Pikrolimni Lake inGreece Geochemical evidencerdquo Journal of Geochemical Explo-ration vol 103 no 2-3 pp 133ndash143 2009

[18] H E Foster and C M Jackson ldquoThe composition of ldquonaturallycolouredrdquo late Roman vessel glass from Britain and the impli-cations for models of glass production and supplyrdquo Journal ofArchaeological Science vol 36 no 2 pp 189ndash204 2009

[19] I C Freestone ldquoAppendix chemical analysis of lsquorawrsquo glass frag-mentsrdquo in Excavations at Carthage Volume II1 The CircularHarbour North SideThe Site and FindsOther than Pottery H RHurst Ed British Academy Monographs in Archaeology N∘4p 290 Oxford University Press Oxford UK 1994

[20] I C Freestone M Ponting and M J Hughes ldquoThe origins ofByzantine glass from Maroni Petrera Cyprusrdquo Archaeometryvol 44 no 2 pp 257ndash272 2002

[21] D C W Sanderson J R Hunter and S E Warren ldquoEnergydispersive X-ray fluorescence analysis of 1stmillennium ad glassfrom Britainrdquo Journal of Archaeological Science vol 11 no 1 pp53ndash69 1984

[22] D Foy M Picon M Vichy and V Thirion-Merle ldquoCar-acterisation des verres de la fin de lrsquoAntiquite en Mediterraneeoccidentale lrsquoemergence de nouveaux courants commerciauxrdquoin Echanges et Commerce du Verre dans le Monde Antique DFoy and M D Nenna Eds Actes du Colloque de lrsquoAssociationFrancaise pour lrsquoArcheologie du Verre Aix-en-Provence etMarseille June 2001 pp 41ndash85 Monique Mergoil MontagnacFrance 2003

[23] D Rosenow and T Rehren ldquoHerding cats Roman to LateAntique glass groups from Bubastis northern Egyptrdquo Journal ofArchaeological Science vol 49 no 1 pp 170ndash184 2014

[24] P Mirti A Casoli and L Appolonia ldquoScientific analysis ofroman glass from augusta praetoriardquo Archaeometry vol 35 no2 pp 225ndash240 1993

[25] A Silvestri G Molin and G Salviulo ldquoRoman and medievalglass from the Italian area bulk characterization and relation-ships with production technologiesrdquo Archaeometry vol 47 no4 pp 797ndash816 2005

[26] A Silvestri S Tonietto and G Molin ldquoThe palaeo-Christianglass mosaic of St Prosdocimus (Padova Italy) archaeometriccharacterisation of lsquogoldrsquo tesseraerdquo Journal of ArchaeologicalScience vol 38 no 12 pp 3402ndash3414 2011

[27] F Gallo and A Silvestri ldquoMedieval glass from Rocca di Asolo(northern italy) an archaeometric studyrdquoArchaeometry vol 54no 6 pp 1023ndash1039 2012

[28] F Gallo A Marcante A Silvestri and G Molin ldquoThe glass ofthe ldquoCasa delle Bestie Feriterdquo a first systematic archaeometricstudy on Late Roman vessels from Aquileiardquo Journal of Archae-ological Science vol 41 pp 7ndash20 2014

[29] S Maltoni T Chinni M Vandini E Cirelli A Silvestri andG Molin ldquoArchaeological and archaeometric study of the glassfinds from the ancient harbour of Classe (Ravenna-Italy) newevidencerdquo Heritage Science vol 3 no 1 article 13 2015

[30] A Ceglia P Cosyns K Nys H Terryn H Thienpont and WMeulebroeck ldquoLate antique glass distribution and consumptionin Cyprus a chemical studyrdquo Journal of Archaeological Sciencevol 61 pp 213ndash222 2015

[31] N Schibille A Sterrett-Krause and I C Freestone ldquoGlassgroups glass supply and recycling in late Roman CarthagerdquoArchaeological and Anthropological Sciences pp 1ndash19 2016

[32] A Cholakova T Rehren and I C Freestone ldquoCompositionalidentification of 6th c AD glass from the Lower DanuberdquoJournal of Archaeological Science Reports vol 7 pp 625ndash6322016

[33] S Conte T Chinni R Arletti and M Vandini ldquoButrint(Albania) between eastern and western Mediterranean glassproduction EMPA and LA-ICP-MS of late antique and earlymedieval findsrdquo Journal of Archaeological Science vol 49 no1 pp 6ndash20 2014

[34] I C Freestone S Wolf and M Thirlwall ldquoThe production ofHIMT glass elemental and isotopic evidencerdquo inAnnales du 16eCongres de lrsquoAssociation Internationale pour lrsquoHistoire du Verre(AIHV rsquo05) pp 153ndash157 London UK 2005

[35] M D Nenna M Picon and M Vichy ldquoAteliers primaries etsecondaries en Egypte a lrsquoepoque greco-romainerdquo in La Routedu Verre Ateliers Primaires et Secondaires du Second Millenaireav J-C au Moyen Age M D Nenna Ed vol 33 pp 97ndash112Travaux de la Maison de lrsquoOrient Mediterraneen 2000

[36] C M Jackson ldquoMaking colourless glass in the Roman periodrdquoArchaeometry vol 47 no 4 pp 763ndash780 2005

[37] E V Sayre ldquoThe intentional use of antimony and manganese inancient glassesrdquo in Advances in Glass Technology Part 2 F R

14 Journal of Chemistry

Matson and G Rindone Eds pp 263ndash282 Plenum Press NewYork NY USA 1963

[38] H E Foster and C M Jackson ldquoThe composition of lateRomano-British colourless vessel glass glass production andconsumptionrdquo Journal of Archaeological Science vol 37 no 12pp 3068ndash3080 2010

[39] J Henderson ldquoThe raw materials of early glass productionrdquoOxford Journal of Archaeology vol 4 no 3 pp 267ndash291 1985

[40] B Gratuze and K Janssens ldquoProvenance analysis of glassartefactsrdquo inNon-Destructive Microanalysis of Cultural HeritageMaterials K Janssens and R Van Grieken Eds pp 663ndash712Elsevier Amsterdam The Netherlands 2004

[41] J Henderson ldquoTradition and experiment in first millenniumAD glass productionmdashthe emergence of early Islamic glasstechnology in late antiquityrdquoAccounts of Chemical Research vol35 no 8 pp 594ndash602 2002

[42] P Mirti M Pace M M Negro Ponzi and M Aceto ldquoICP-MSanalysis of glass fragments of Parthian and Sasanian epoch fromSeleucia and Veh Ardasır (Central Iraq)rdquoArchaeometry vol 50no 3 pp 429ndash450 2008

[43] P Mirti M Pace M Malandrino and M N Ponzi ldquoSasanianglass from Veh Ardasır new evidences by ICP-MS analysisrdquoJournal of Archaeological Science vol 36 no 4 pp 1061ndash10692009

[44] J Hoefs Stable Isotope Geochemistry Springer Berlin Ger-many 5th edition 2004

[45] A Silvestri G Molin and G Salviulo ldquoThe colourless glass ofIulia Felixrdquo Journal of Archaeological Science vol 35 no 2 pp331ndash341 2008

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Hindawi Publishing Corporation httpwwwhindawicom Volume 201

International Journal ofInternational Journal ofPhotoenergy

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Carbohydrate Chemistry

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Advances in

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Analytical Methods in Chemistry

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Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Medicinal ChemistryInternational Journal of

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Quantum Chemistry

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Organic Chemistry International

ElectrochemistryInternational Journal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

6 Journal of Chemistry

Table 5 12057518O(VSMOW) of chert samples from the quarries in Triadiof Thessaloniki (Central Macedonia Greece)

Samples 12057518O(VSMOW) MeanTrd 1-1 250 251 250Trd 1-2 234 235 234Trd 1-4 236 238 237Trd 1-5 260 261 260Trd 2-1 242 244 243Trd 3-1 261 260 260Trd 3-2 258 260 259Trd 5-2 225 223 224

Mean value 246 plusmn 14permil

Lastly sample 8-4 fromThessaloniki with 12057518O equal to156permil is characterised by lower silicium and sodium con-tents and higher calcium aluminium potassium magne-sium and phosphorous contents (Table 4) than other glasseswith comparable isotopic composition

In addition to samples with isotopic signatures rangingfrom 152 to 160permil the isotopic data indicate that foursamples fromThessaloniki are heavily enriched by about 7permilsample 12-4 has 12057518O equal to 205permil and samples 1-3 2-3and 9-4 have values from 225 to 227permil Finally other fivesamples fromThessaloniki (3-3 6-3 3-4 10-4 and 13-4) showmoderate 18O enrichment with values between 161 and186permil (Table 4)

The chemical analyses of the heavily enriched glass(Table 4) show that all samples are characterised by higherCaO K2O MgO and P2O5 and lower Na2O and Al2O3contents than other Greek samples with lower isotopic com-position In addition sample 12-4 also has exceptionally highmanganese (MnO = 438wt Table 4)

The samples with moderate 18O enrichment show quitevariable chemical compositions but comparable to those ofsamples with lower and higher isotopic compositions Sam-ples 3-3 (12057518O= 186permil) and 10-4 (12057518O= 164permil) have chem-ical compositions comparable to those of samples 5-3 4-4and 5-4 although sample 10-4 has very little Mn and highCu and Pb (Table 4) Sample 6-3 (12057518O = 173permil) is similarin chemical composition to samples 1-1 5-1 8-1 91 4-3 6-4 11-4 and 14-4 from Thessaloniki (Tables 2 and 4) and allthe samples from Maroneia (Table 3) Finally the chemicalcomposition of sample 13-4 (12057518O = 173permil) is very similar tothose of the heavily enriched glass as deduced from itslow Na2O and Al2O3 and high CaO K2O MgO and P2O5contents (Table 4)

The isotopic data obtained on the chert samples from thequarries in Triadi ofThessaloniki show that mean 12057518O value(equal to 246 plusmn 14permil Table 5) is comparable to those ofGreek glass samples heavily enriched (mean 12057518O value =221 plusmn 11permil) Mineralogical data obtained by means ofXRPD show chert samples are a mixture of quartz andgoethite (semiquantitative contents of the two phases 94quartz and 6 goethite) except for sample Trd 1-5 composedof only quartz (Figure 1)

XRF data furtherly confirm the mineralogical composi-tions sample Trd 1-2 being almost entirely composed of SiO2and Fe2O3 and Trd 1-5 of only SiO2 (Table 6)

32 Discussion The majority of the analysed samples fromThessaloniki and all the samples from Maroneia have ahomogeneous oxygen isotopic composition (12057518O value =156 plusmn 025permil Table 2 and Figure 2) which is equal orvery close to the mean value of ldquoRomanrdquo glass as deducedfrom a set of isotopic measurements on glass from Europedated from the 1st to the 4th centuries AD which show arelatively narrow range of 12057518O (from about 154permil to 160permil)[2 3] Similar results (Figure 2) were also obtained for lateAntiqueearly Medieval samples from Grado and Vicenzatwo sites in Northern Italy [3] and for coeval glass from theNear East [11 12]

These similarities may be explained by assuming thatthe Greek glass samples were produced with raw materialswith equal or very similar oxygen isotopic compositionSand from the rivers Belus in Palestine and Volturno inItaly mentioned by Pliny the Elder in Naturalis Historia asmaterials for making glass is suitable for glass productionand has the same oxygen isotopic composition when theVolturno sandundergoes selective grinding [3] It follows thatglass produced with either Belus or Volturno sand as networkformer and natron as flux is practically indistinguishablefrom the oxygen isotopic point of view Consequently theisotopic composition of most of the Greek samples in Tables2 3 and 4 cannot help to distinguish among glass samplesimported from Italy or the Near East or glass samplesproduced inGreek secondary glassworkshops bymelting rawglass from the geographic point of view a Levantine originfor the Greek glass samples is quite reasonable This origin isreinforced by data reported in Brill [13] on five cullets froman ancient glass workshop at Jalame in western Galilee (3rd-4th centuries AD) The author suggests that the silica usedfor these cullets came from sand taken from the mouth ofthe Belus and that the oxygen isotopic composition of quartzwas enriched in 18O by the calcium carbonate contained inthe sand in the form of sea shells with natron as flux The12057518O values of the Jalame glass are slightly lower than thoseof Greek samples and range from about 14 to 15permil (Figure 2)Although the use of various other raw materials cannot becompletely excluded this small difference may be explainedby amounts of natron used for melting which are slightlysmaller in Jalame than in Greek glass samples The oxygenisotopic study carried out by Silvestri et al [3] on Romannatron glass demonstrated the ldquopositive natron effectrdquo that isit is presumed that flux which has very positive 12057518O valuescaused 18O enrichment in the final glass as confirmed bythe plot of Na2O versus 12057518O which clearly shows a positivecorrelation Other glass samples from the Near East have12057518O values close to those of our samples showing ldquoRomanrdquovalues (Figure 2) These samples measured by Leslie et al[12] came from different locations three from the BethShersquoan in Israel (6th-7th centuries AD) mean value 146permilthree from Tel el-Ashmunein in Egypt (8th-9th centuries)mean value 148permil and three from Carthage in Tunisia

Journal of Chemistry 7

10 20 30 40 50 60 70

Cou

nts

0

TRD-1-2

Peak list

Goethite syn FeO(OH)

50000

100000

150000

Quartz low SiO2

Position (∘2휃) (copper (Cu))

(a)

TRD-1-5

10 20 30 40 50 60 70

Cou

nts

Peak list

0

100000

200000

Quartz low SiO2

Position (∘2휃) (copper (Cu))

(b)

Figure 1 XRPD patterns of chert samples named Trd 1-2 (a) and Trd 1-5 (b) representative of the twomineralogical compositions identified

(4thndash6th centuries) mean value 150permil All these samplesare obtained using natron from the evaporitic lakes of WadiNatron in Egypt The provenance of sand from a relativelyshort stretch of the eastern Mediterranean coast is suggestedfor the Beth Shersquoan samples and the similarity between thedelta values of the Tel el-Ashmunein and Carthage samplesis explained by their production with the same Egyptiansand The isotopic similarity among these three groups ofsamples can be explained taking into account a commonprovenance for natron and that Levantine sand comes fromEgypt and is transported up to the eastern Mediterraneancoast by sea currents [14 15] therefore the use of sandand flux with similar provenance yields glass samples withsimilar isotopic compositions The same source may thusbe hypothesised for the Greek glass samples analysed hereHowever it should be stressed that natural natron depositsin the region of Macedonia in northern Greece were well-known in the time of Plato (5th century BC) and werealso described by Pliny the Elder in his Naturalis HistoriaeHatzopoulos and Loukopoulou [16] identified Lake Chalastra(so-called in antiquity that is the place where the ldquoCha-lastraion nitronrdquo formed and dissolved over a period of afew days) as the modern lake of Picrolimni located about20 km NW of Thessaloniki The geochemical conditionsresponsible for the formation of ldquoChalastraion nitronrdquo haverecently been studied and discussed by Dotsika et al [17]The salts deposited by the lake brine were mineralogicallyidentified by XRD analysis and include not only calcite anddolomite but also trona (Na2CO3sdotNaHCO3sdot2H2O) burkeite(Na2CO3sdot2Na2SO4) and halite (NaCl) thus confirming themineralogical similarity between these deposits and thosefrom Wadi Natron in Egypt However the oxygen isotopiccompositions determined on the Picrolimni salt deposits

range from about 11 to 25permil (VSMOW) much lower than thevalues for Wadi Natron (about 34 to 40permil [2 3]) Thereforein the case of our samples use of ldquoChalastraion nitronrdquo as fluxcan hardly be considered

In contrast with the remarkable isotopic homogeneity ofthe majority of Greek samples (2939 samples) the chemicalcomposition is rather heterogeneous (Tables 2 3 and 4)although they are all obtainedwith natron as flux having bothK2O and MgO contents lower than 15 wt In particularsamples 1-1 5-1 8-1 9-1 4-3 6-4 11-4 and 14-4 fromThessaloniki (Tables 2 and 4) and all the samples fromMaroneia (Table 3) show the HIMT (High Iron Magnesiumand Titanium) signature This reference group is defined byhigh levels of iron (ge07 wt)manganese (usually sim1-2 wt)magnesium (usuallyge08 wt) and titanium (ge01 wt) andits yellow-green colour is due to the amount of iron sugges-tive of a relatively impure sand source [18] These also are thekey characteristics of Greek glass samples which have highFeO (120 plusmn 031wt) MnO (154 plusmn 035wt) MgO (124 plusmn016wt) and TiO2 (018plusmn005wt) contentsThe acronymHIMT was first applied by Freestone [19] to raw glass fromCarthage and glass vessels from Cyprus [20] although glasswith high contents of iron manganese and titanium wasalready identified by Sanderson et al [21] However all theGreek samples (except 4-3) containing about 50ndash60 of theamount of iron titanium and manganese oxides measuredin ldquotypicalrdquo HIMT glass such as Group 1 of Foy et al [22](about 121 plusmn 031wt as FeO 017 plusmn 003wt as TiO2and 151 plusmn 037wt as MnO versus 2 plusmn 08wt as FeO05 plusmn 01wt as TiO2 and 22 plusmn 04wt as MnO for Greeksamples and Group 1 resp) show a better fit with ldquoGroup 2rdquoof Foy et al [22] whichmay be considered as a ldquoweakrdquo HIMTglass [18] due to lower contents of the key oxides of HIMT

8 Journal of Chemistry

Table6Ch

emicalcompo

sitions

ofchertsam

plesn

amed

Trd1-2

andTrd1-5

representativeof

thetwomineralogicalcompo

sitions

identifi

ed(X

RFdataL

OIlosson

ignitio

n)N

otethat

GaYNbLaC

eandUcontentsaren

otrepo

rted

becausetheyarelow

erthan

XRFdetectionlim

itsfora

llsamples

(LODof

Ga=

5ppm

LODof

YNbandU=3p

pmLODof

LaandCe=

10pp

m)

Sample

SiO2

TiO2

Al 2O3

Fe2O3

MnO

MgO

CaO

Na 2O

K 2O

P 2O5

LOI

ScV

CrCo

Ni

CuZn

RbSr

ZrBa

Nd

PbTh

Num

berWt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

Trd1-2

9068

001

021

713

015

037

012

005

001

002

218

9314

507

124

146

1846

78

920

1912

7Trd1-5

9998lt00

05lt00

2lt00

05lt00

05lt00

2lt00

05lt00

2lt00

05lt00

05000lt3lt3lt3lt3lt3lt3lt3lt3lt3lt3lt10lt10lt10lt3

Journal of Chemistry 9

10 11 42 10 9 5 9 16 414

15

16

17

18

19

Number of samples

훿18O

(VSM

OW

)(permil

)

Figure 2 Comparisons among 12057518O(VSMOW) values of natron glasssamples [open symbols Thessaloniki Agora (◻) Maroneia ()Thessaloniki various sites (998779)Thessaloniki glass withmoderate 18Oenrichment (I)] and those already reported in the literature [fullsymbols Roman glass from Europe (◼) [2] Roman glass from IuliaFelix (X) [3] 4th century AD glass from Jalame (998771) [2] HIMTglass from Carthage and Levantine natron glass (bold plus sign)[12] late Antique-earlyMedieval glass fromGrado ad Vicenza (boldmultiplication sign) [3]] Number of analysed samples is also shown

glass (Figure 3) Instead sample 4-3 has FeO TiO2 andMnO contents (Table 4) perfectly comparable with ldquotypicalrdquoHIMT glass [18 22] In general HIMT glass has also beenidentified in Britain [18] Egypt [23] France [22] Italy [24ndash29] Cyprus [20 30] Carthage [31] Bulgaria [32] andAlbania[33] The chemical and isotopic signatures of HIMT glass aresuggestive of continental sand sources of high maturity richin heavy minerals and located in the Near East probablyin Egypt [12 31 34] As regards the dating of the referencegroups in general terms the HIMT group is probably morecharacteristic of the period from the mid-4th century ADonwards although according to current research its compo-sition seems to have continued after the 5th century [18]In addition according to Schibille et al [31] ldquoGroup 2rdquo isdated to the 5th-6th centuries and is thus coeval with theglass from Maroneia Consequently the age of Thessalonikiglass samples similar in composition to those of ldquoGroup 2rdquois constrained to the late Antique period

The other glass samples from Thessaloniki (2-1 3-1 6-17-1 5-3 7-3 4-4 5-4 and 7-4) whose 12057518O is in therange of ldquoRomanrdquo values also show the chemical compo-sition typical of Roman glass [35] although they differ incontents of manganese and antimony (Figure 3) and traceelements In particular samples 3-1 5-3 4-4 and 5-4 showMnO gt 05 wt which suggests its intentional addition asa decolouriser [36] whereas sample 6-1 has no manganesebut antimony (Table 2) As these two elements the principal

decolourisers used between the 1st and 4th centuries ADwere both predominant from the late 1st to the 3rd centuriesand as the use of manganese increased from the end of the3rd to the 4th century [36ndash38] the age of these samples isconstrained accordingly Instead samples 3-1 and 7-3 do notreveal any intentional addition of decolouriser having noantimony and MnO lt 05 wt (Tables 2 and 4) Sample 2-1from Thessaloniki Agora has relatively high concentrationsof CuO SnO2 PbO and P2O5 (Table 2) suggesting theinclusion of cullet perhaps coloured and opaque mosaictesserae containing high quantities of one or more of theseelements in the glass batch The chemical composition ofsample 7-1 is not far from that of sample 2-1 although the con-centrations of copper and lead are much lower than those insample 2-1 (Table 2) This indicates that the presence ofthe above elements is due to recycling of earlier colouredglass because they occur in concentrations higher than thoseattributable to impurities in the raw materials but too low tohave any technological significance [39] Conversely the highCu in sample 7-4 not associated with high Sn Co Pb Sband Zn (Table 4) suggests that this element was intentionallyadded to produce the aquamarine colour

Lastly chemical similarities between samples 4-1 and 10-1from Thessaloniki Agora and data reported in the literatureare difficult to establish Sample 4-1 seems quite comparablewith some soda-potash-lime glass from the 14th-centuryworkshop at Saint-Chely (France) Two different hypothesesboth equally valid from an analytical point of view are pro-posed to explain the peculiar chemical composition of theseLate Medieval French samples [40] both soda and potashash were used by the glass-workers soda ash remaining themain component recycled glass from the surrounding areaswith both potash and soda ash compositions was used asrawmaterials Sample 10-1 also approaches although not per-fectly the composition of ldquomixed soda-potash glassrdquo dated toLate Bronze age [40] and the oxygen isotopic data obtained byBrill et al [2] on some Late Bronze age objects are also quitecomparable with that of sample 10-1 On the contrary oxygenisotope data on samples with chemical composition similarto sample 4-1 are unfortunately still lacking although dataon Medieval soda ash and late Medieval and modern potashash glass are systematically lower and range from about 12to 145permil [2 3] In any case both isotopic and chemical datasuggest that the age proposed for samples 4-1 and 10-1 fromThessaloniki Agora should be revised

The chemical analyses of the heavily enriched glass(Table 4) show that all samples were melted with soda ashas flux their K2O MgO and P2O5 contents being higherthan those of the other samples (Figure 3) The low Al2O3content suggests that as well as flux a different silica sourcewas used to produce these samples Leslie et al [12] reportsome highly variable isotopic results from glass samples10thndash13th centuries in age from Rarsquos al-Hadd (Oman) one ofwhich is close to 20permil (Figure 4) Heavily enriched 12057518Ovalues which range from 216 to 226permil have already beenmeasured by Brill et al [2] on glass samples from Nimrud(Iraq) dated to the 7th century BC the author obviouslyconcluded that ldquothese glasses must represent a glassmaking

10 Journal of Chemistry

60 64 68 72 76 808

12

16

20N

a 2O

(wt

)

SiO2 (wt)

(a)

0 2 4 6

Natron

Soda plant ash

0

1

2

3

4

MgO

(wt

)

K2O (wt)

(b)

4 6 8 10 120

1

2

3

4

Al 2O

3 (w

t)

CaO (wt)

(c)

0 05 1 15 2 250

1

2

3

4

5

MnO

(wt

)

FeO (wt)

(d)

Figure 3 Na2O versus SiO2 (a) MgO versus K2O (b) Al2O3 versus CaO (c) and MnO versus FeO (d) contents of Greek glass samplessubdivided by provenance Thessaloniki Agora () Maroneia (I) Thessaloniki various sites (998779 natron glass 998771 soda ash glass) Meanchemical compositions and standard deviations of main compositional natron groups identified in literature and comparable with Greeksamples are also shown ldquoRomanrdquo glass (bold plus sign) Group 2 (bold multiplication sign) [22 35]

tradition thatmade use of some particular rawmaterialrdquo Twosamples from Aphrodisias (Turkey) 6th-7th centuries ADin age also yielded 12057518O values of about 234permil (Figure 4)All the samples reported in the literature with very positive12057518O values were obtained with soda ash as flux althoughthey show lowerK2OMgOandhigherNa2OK2Oratios thanGreek samples suggesting the use of different kinds of plantash

In Europe and Mediterranean area soda ash glass datesfrom the 9th century AD onwards [4 41] This wouldexclude a Roman age for Greek soda ash samples unlessthey were produced with raw glass imported from areas suchas Mesopotamia and Iran where plant ash continued to beused as flux in glass production throughout the period ofnatron dominance in the West [4] However so far chemicalcomparisons with 3rdndash7th-century soda ash glass from Iraq

Journal of Chemistry 11

7 6 2 8 6

12

16

20

24훿18O

(VSM

OW

)(permil

)

Number of samples

Figure 4 Comparisons among 12057518O(VSMOW) values of plant ash glasssamples [open symbols Thessaloniki various sites (◻)] and thosealready reported in the literature [full symbols glass from Nimrudand Aphrodisias (◼) [2] glass from Rarsquos al-Hadd (e) and Levantinesoda ash glass (X) [12] Medieval soda ash glass from Italy (998771) [3]]Number of analysed samples is also shown

[42 43] have not shown any consistency with Greek samplesIn addition the heavily enriched 12057518O values do indicatethat their raw materials differed from those normally used inRoman andMedieval glass production and this wouldmatchthe possibility of the different origin of these materials Theuse of ash as flux may cause some 18O enrichment when theash is particularly rich in carbonate bicarbonate and hydrate[4] but hardly to this extent Previous oxygen isotopic dataobtained on Medieval soda ash glass from the Western andEastern Mediterranean (Figure 4) indicate that the additionof ash did not contribute to isotopically heavy oxygen and the12057518Ovalues essentially reflect the silica source (eg [2 3 12])In the case of Greek heavily enriched glass the silica source isdifficult to identify taking into account the fact that quartzwith anomalously heavy isotopic composition is uncommoninmagmatic sedimentary or metamorphic rocks Due to thelarge oxygen isotopic fractionation between SiO2 andwater atlow temperatures biogenic silica and chert have the highest18O16O ratios observed in rocks [44] Therefore the Greeksamples with high isotopic values may be the product oflocal glass workshops which used raw materials composedof chert with the addition of ash probably obtained fromvarious plant species other than those considered by Titeet al [4] or differently pretreated The isotopic chemicaland mineralogical data obtained on a selection of chertsamples from the quarries in Triadi of Thessaloniki (CentralMacedonia Greece) furtherly support the hypothesis of localproduction at least if we consider sample Trd 1-5 composedof only quartz

In the case of samples with moderate 18O enrichmentseveral causes must be considered to explain their valuesSample 3-3 (12057518O= 186permil) has a chemical composition quiteclose to that of Roman glass decolourised by the addition ofMn [45] sample 6-3 (12057518O= 173permil) is chemically comparableto ldquoGroup 2rdquo of Foy et al [22] and its suggested age (6thcentury AD) matches the chronological diffusion of the ref-erence group However both samples have 12057518O higher thanthe average ldquoRomanrdquo or ldquoHIMTrdquo values

In view of the high Na2O content of samples 3-3 and 6-3(Table 4) 18O enrichment may be explained by remelting ofprevious glass with addition of further amounts of natron asflux which causes an increase in Na2O concentration and inthe 18O content of the final products

Apart from their slightly higher 12057518O values (161 and164permil resp) samples 3-4 and 10-4 show quite differentchemical compositions Sample 3-4 is chemically comparablewith ldquoGroup 2rdquo [22] the chronological diffusion ofwhich alsomatches the age proposed (5th-6th centuries AD) whereassample 10-4 is similar to Roman glass 1stndash3rd centuries Adin age although the presence of Cu and Pb may also indicaterecycling of coloured and opaque glass as in the case ofsample 7-1 Both samplesmay be produced in local secondaryworkshops by recycling previous glass (perhaps from theLevantine area) with the addition of further amounts ofnatron as flux as suggested by their high Na2O content(Table 4) thus increasing the 18Ocontent of the final product

According to its chemical composition sample 13-4(Table 4 12057518O= 173permil) was obtained with soda ash as flux asdeduced from its high K2O MgO and P2O5 contents Wesuggest a different starting material for this sample as in thecase of other soda plant ash glass identified in the Greekassemblage

Lastly sample 8-4 from Thessaloniki has 12057518O of 156permilthat is within the average Roman values suggesting the use ofBelus or Volturno sand and Egyptian natron as rawmaterialsbut its chemical composition is comparable to that of glassproduced with soda plant ash as flux The chronologicaldiffusion of soda ash glass in Europe andMediterranean area[4 41] excludes a Roman age for this sample and chem-ical comparisons with 3rdndash7th-century soda ash glass fromIraq [42 43] where plant ash continued to be used as fluxthroughout the period of natron dominance in the West [4]have not shown any consistency with the present sampleTherefore great uncertainty remains in the case of sample 8-4 as regards both its age and provenance also in view of theheavily enriched oxygen signatures of other soda ash samplesidentified here (Table 4) However sample 8-4 differs fromthe others due to its lower SiO2 (616 wt) and higher Al2O3(390wt) which suggest a different silica source probably asilica sand rich in feldsparsThis source may be characterisedby a less positive oxygen signature probably related to thefeldspars content of the sand which influences the 18Ocontent of the final productThis hypothesis is also supportedby the isotopic and chemical signatures of sample 13-4Obtained again with soda plant ash as flux this sample hasAl2O3 content intermediate between that of sample 8-4 andall other Greek soda ash samples and consequently shows anintermediate 12057518O value

12 Journal of Chemistry

4 Conclusions

The results of the present study emphasize the importanceof measuring the oxygen isotopic and chemical compositionsof glass samples in order to constrain some features such asage raw materials and production technology Comparisonsof our isotopic and chemical data with those reported in theliterature particularly in the case of glass from the Levantinearea are of particular interest as regards the trading ofraw glass to secondary workshops in Greece although forsome samples obtained with soda ash as flux and heavilyenriched in 18O production from local raw materials cannotbe completely excluded

In summary the thirty-nine glass samples from northernGreece studied here have oxygen isotopic compositionswhich allow them to be subdivided into three groups

The first is composed of twenty-nine samples (severalfrom Thessaloniki and all those from Maroneia) with 12057518Ovalues equal or very close to themean value of Roman glassesfrom European and Middle Eastern areas These similaritiesimply their production with raw materials with equal or veryclose oxygen isotopic composition such as sand from therivers Belus in Palestine and Volturno in Italy as suggestedby Pliny the Elder In contrast with the remarkable isotopichomogeneity heterogeneous chemical compositions allowthe subdivision of these samples into several subgroupswhich are compared with major compositional groups iden-tified in the Western Mediterranean during the first millen-nium AD

Seven samples from Thessaloniki and all the samplesfrom Maroneia show chemical similarity with ldquoGroup 2rdquo ofFoy et al [22] while one sample shows chemical simi-larity with HIMT glass Accordingly their age should beconstrained to the late Antique period for the Thessalonikiglass and confirmed for the Maroneia samples (ie 4thndash6thcenturies AD) Nine samples from Thessaloniki are chemi-cally comparable with Roman glass although they differ incolouringdecolouring elements and recycling indicators Inparticular in some samples the identification of manganeseintentionally added as a decolourant allows us to constraintheir age according to the chronological diffusion reported inthe literature of this decolourant that is from the 3rd to 4thcenturies AD Lastly three samples from Thessaloniki(1stndash6th centuries AD) with 12057518O values comparable withldquoRomanrdquo values have chemical compositions very differentfrom ldquotypicalrdquo Roman glass suggesting different productiontechnologies

The second isotopic group is composed of four samplesfrom Thessaloniki showing heavily enriched 12057518O values(205 to 227permil) their chemical analyses indicate that theywere obtained using soda ash as flux which has little effect onthe final oxygen isotopic composition of glass These high12057518O values may be explained by the use of silica rawmaterials with heavy 18O enrichment such as chert which isalso found in the Thessaloniki region Therefore these sam-ples may be the product of local glass factories

The third group is composed of five samples from Thes-saloniki showing moderate 18O enrichment (161 to 186permil)

From the chemical point of view four samples are natronglass with compositions similar to Roman or ldquoweakrdquo HIMTgroups and one is a soda ash glass In the case of natron glassthe moderate 18O enrichment may be obtained by recyclingglass (perhaps from the Levantine area) in local secondaryworkshops with the addition of further amounts of natron asflux as suggested by their high Na2O contents In the case ofsoda ash themoderate 18O enrichment with respect to otherGreek soda ash glass may be due to the use of less positivesilica source

In conclusion these interesting results the first obtainedon glass samples from northern Greece support trades andcommercial exchanges between theNear East andGreece andsuggest although further data are required to confirm it thatthe ldquofingerprintrdquo ofGreek glass production could be related tothe use of local chert and soda ash as possible raw materials

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

The authors are grateful to D Grammenos director ofthe Archaeological Museum of Thessaloniki for providingglass samples from Thessaloniki R Carampin (Istituto diGeoscienze e Georisorse Sezione di Padova CNR) F Gallo(Dipartimento dei Beni Culturali Universita di Padova) andD Pasqual (Dipartimento diGeoscienze Universita di Padova)are thanked for their kind support to execution of chemicalanalyses Financial support was provided by ldquoEx 60rdquo fundsof the University of Padova (principal investigator AlbertaSilvestri)

References

[1] R Newton andD DavisonConservation of Glass Butterworth-Heinemann Oxford UK 1999

[2] R H Brill R N Clayton T K Mayeda and C P StapletonldquoOxygen isotope analyses of early glassesrdquo in Chemical Analysesof Early Glasses R H Brill Ed vol 2 pp 303ndash322 CorningMuseum of Glass New York NY USA 1999

[3] A Silvestri A Longinelli andGMolin ldquo12057518Omeasurements ofarchaeological glass (Roman toModern age) and rawmaterialspossible interpretationrdquo Journal of Archaeological Science vol37 no 3 pp 549ndash560 2010

[4] M S Tite A Shortland Y Maniatis D Kavoussanaki and S AHarris ldquoThe composition of the soda-rich and mixed alkaliplant ashes used in the production of glassrdquo Journal of Archae-ological Science vol 33 no 9 pp 1284ndash1292 2006

[5] C Antonaras ldquoGlass working in Roman and early ChristianThessaloniki older and more recent findsrdquo in Proceedings of theHistory Technology and Conservation of Ancient Metals Glassesand Enamels International Symposium Athens Greece Novem-ber 2011

[6] I Friedman and J R OrsquoNeil ldquoCompilation of stable isotopefractionation factors of geochemical interestrdquo in Data of

Journal of Chemistry 13

Geochemistry Geological Survey Professional Paper 440-KKchapter KK 1977

[7] A Silvestri and A Marcante ldquoThe glass of Nogara (Verona) aldquowindowrdquo on production technology of mid-Medieval times inNorthern Italyrdquo Journal of Archaeological Science vol 38 no 10pp 2509ndash2522 2011

[8] S Alberta M Gianmario and P Valentina ldquoThe stained glasswindow of the southern transept of St Anthonyrsquos Basilica(Padova Italy) study of glasses and grisaille paint layersrdquoSpectrochimica ActamdashPart B Atomic Spectroscopy vol 66 no1 pp 81ndash87 2011

[9] K Govindaraju ldquoCompilation of working values and sampledescription for 383 geostandardsrdquoGeostandards Newsletter vol18 pp 1ndash158 1994

[10] A Savitzky andM J EGolay ldquoSmoothing anddifferentiation ofdata by simplified least squares proceduresrdquo Analytical Chem-istry vol 36 no 8 pp 1627ndash1639 1964

[11] J Henderson J A Evans H J Sloane M J Leng and CDoherty ldquoThe use of oxygen strontium and lead isotopesto provenance ancient glasses in the Middle Eastrdquo Journal ofArchaeological Science vol 32 no 5 pp 665ndash673 2005

[12] K A Leslie I C Freestone D Lowry and M Thirlwall ldquoTheprovenance and technology of Near Eastern glass oxygenisotopes by laser fluorination as a complement to strontiumrdquoArchaeometry vol 48 no 2 pp 253ndash270 2006

[13] R H Brill ldquoScientific investigations of the Jalame glass andrelated findsrdquo in Excavations at Jalame Site of a Glass Factory inLate Roman Palestine G D Wienberg Ed pp 257ndash293University of Missouri Press Columbia Mo USA 1988

[14] M Pomerancblum ldquoThe distribution of heavy minerals andtheir hydraulic equivalents in sediments of the Mediterraneancontinental shelf of Israelrdquo SEPM Journal of SedimentaryResearch vol 36 pp 162ndash174 1966

[15] D J Stanley Y Mart and Y Nir ldquoClay mineral distributions tointerpret Nile cell provenance and dispersal II Coastal plainfrom Nile delta to northern Israelrdquo Journal of Coastal Researchvol 13 no 2 pp 506ndash533 1997

[16] M B Hatzopoulos and L D Loukopoulou Morrylos Centrede Recherches de lrsquoAntiquite Grecque et Romaine AthenesGreece 1989

[17] E Dotsika D Poutoukis I Tzavidopoulos Y Maniatis DIgnatiadou and B Raco ldquoA natron source at Pikrolimni Lake inGreece Geochemical evidencerdquo Journal of Geochemical Explo-ration vol 103 no 2-3 pp 133ndash143 2009

[18] H E Foster and C M Jackson ldquoThe composition of ldquonaturallycolouredrdquo late Roman vessel glass from Britain and the impli-cations for models of glass production and supplyrdquo Journal ofArchaeological Science vol 36 no 2 pp 189ndash204 2009

[19] I C Freestone ldquoAppendix chemical analysis of lsquorawrsquo glass frag-mentsrdquo in Excavations at Carthage Volume II1 The CircularHarbour North SideThe Site and FindsOther than Pottery H RHurst Ed British Academy Monographs in Archaeology N∘4p 290 Oxford University Press Oxford UK 1994

[20] I C Freestone M Ponting and M J Hughes ldquoThe origins ofByzantine glass from Maroni Petrera Cyprusrdquo Archaeometryvol 44 no 2 pp 257ndash272 2002

[21] D C W Sanderson J R Hunter and S E Warren ldquoEnergydispersive X-ray fluorescence analysis of 1stmillennium ad glassfrom Britainrdquo Journal of Archaeological Science vol 11 no 1 pp53ndash69 1984

[22] D Foy M Picon M Vichy and V Thirion-Merle ldquoCar-acterisation des verres de la fin de lrsquoAntiquite en Mediterraneeoccidentale lrsquoemergence de nouveaux courants commerciauxrdquoin Echanges et Commerce du Verre dans le Monde Antique DFoy and M D Nenna Eds Actes du Colloque de lrsquoAssociationFrancaise pour lrsquoArcheologie du Verre Aix-en-Provence etMarseille June 2001 pp 41ndash85 Monique Mergoil MontagnacFrance 2003

[23] D Rosenow and T Rehren ldquoHerding cats Roman to LateAntique glass groups from Bubastis northern Egyptrdquo Journal ofArchaeological Science vol 49 no 1 pp 170ndash184 2014

[24] P Mirti A Casoli and L Appolonia ldquoScientific analysis ofroman glass from augusta praetoriardquo Archaeometry vol 35 no2 pp 225ndash240 1993

[25] A Silvestri G Molin and G Salviulo ldquoRoman and medievalglass from the Italian area bulk characterization and relation-ships with production technologiesrdquo Archaeometry vol 47 no4 pp 797ndash816 2005

[26] A Silvestri S Tonietto and G Molin ldquoThe palaeo-Christianglass mosaic of St Prosdocimus (Padova Italy) archaeometriccharacterisation of lsquogoldrsquo tesseraerdquo Journal of ArchaeologicalScience vol 38 no 12 pp 3402ndash3414 2011

[27] F Gallo and A Silvestri ldquoMedieval glass from Rocca di Asolo(northern italy) an archaeometric studyrdquoArchaeometry vol 54no 6 pp 1023ndash1039 2012

[28] F Gallo A Marcante A Silvestri and G Molin ldquoThe glass ofthe ldquoCasa delle Bestie Feriterdquo a first systematic archaeometricstudy on Late Roman vessels from Aquileiardquo Journal of Archae-ological Science vol 41 pp 7ndash20 2014

[29] S Maltoni T Chinni M Vandini E Cirelli A Silvestri andG Molin ldquoArchaeological and archaeometric study of the glassfinds from the ancient harbour of Classe (Ravenna-Italy) newevidencerdquo Heritage Science vol 3 no 1 article 13 2015

[30] A Ceglia P Cosyns K Nys H Terryn H Thienpont and WMeulebroeck ldquoLate antique glass distribution and consumptionin Cyprus a chemical studyrdquo Journal of Archaeological Sciencevol 61 pp 213ndash222 2015

[31] N Schibille A Sterrett-Krause and I C Freestone ldquoGlassgroups glass supply and recycling in late Roman CarthagerdquoArchaeological and Anthropological Sciences pp 1ndash19 2016

[32] A Cholakova T Rehren and I C Freestone ldquoCompositionalidentification of 6th c AD glass from the Lower DanuberdquoJournal of Archaeological Science Reports vol 7 pp 625ndash6322016

[33] S Conte T Chinni R Arletti and M Vandini ldquoButrint(Albania) between eastern and western Mediterranean glassproduction EMPA and LA-ICP-MS of late antique and earlymedieval findsrdquo Journal of Archaeological Science vol 49 no1 pp 6ndash20 2014

[34] I C Freestone S Wolf and M Thirlwall ldquoThe production ofHIMT glass elemental and isotopic evidencerdquo inAnnales du 16eCongres de lrsquoAssociation Internationale pour lrsquoHistoire du Verre(AIHV rsquo05) pp 153ndash157 London UK 2005

[35] M D Nenna M Picon and M Vichy ldquoAteliers primaries etsecondaries en Egypte a lrsquoepoque greco-romainerdquo in La Routedu Verre Ateliers Primaires et Secondaires du Second Millenaireav J-C au Moyen Age M D Nenna Ed vol 33 pp 97ndash112Travaux de la Maison de lrsquoOrient Mediterraneen 2000

[36] C M Jackson ldquoMaking colourless glass in the Roman periodrdquoArchaeometry vol 47 no 4 pp 763ndash780 2005

[37] E V Sayre ldquoThe intentional use of antimony and manganese inancient glassesrdquo in Advances in Glass Technology Part 2 F R

14 Journal of Chemistry

Matson and G Rindone Eds pp 263ndash282 Plenum Press NewYork NY USA 1963

[38] H E Foster and C M Jackson ldquoThe composition of lateRomano-British colourless vessel glass glass production andconsumptionrdquo Journal of Archaeological Science vol 37 no 12pp 3068ndash3080 2010

[39] J Henderson ldquoThe raw materials of early glass productionrdquoOxford Journal of Archaeology vol 4 no 3 pp 267ndash291 1985

[40] B Gratuze and K Janssens ldquoProvenance analysis of glassartefactsrdquo inNon-Destructive Microanalysis of Cultural HeritageMaterials K Janssens and R Van Grieken Eds pp 663ndash712Elsevier Amsterdam The Netherlands 2004

[41] J Henderson ldquoTradition and experiment in first millenniumAD glass productionmdashthe emergence of early Islamic glasstechnology in late antiquityrdquoAccounts of Chemical Research vol35 no 8 pp 594ndash602 2002

[42] P Mirti M Pace M M Negro Ponzi and M Aceto ldquoICP-MSanalysis of glass fragments of Parthian and Sasanian epoch fromSeleucia and Veh Ardasır (Central Iraq)rdquoArchaeometry vol 50no 3 pp 429ndash450 2008

[43] P Mirti M Pace M Malandrino and M N Ponzi ldquoSasanianglass from Veh Ardasır new evidences by ICP-MS analysisrdquoJournal of Archaeological Science vol 36 no 4 pp 1061ndash10692009

[44] J Hoefs Stable Isotope Geochemistry Springer Berlin Ger-many 5th edition 2004

[45] A Silvestri G Molin and G Salviulo ldquoThe colourless glass ofIulia Felixrdquo Journal of Archaeological Science vol 35 no 2 pp331ndash341 2008

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 201

International Journal ofInternational Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal ofInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Journal of Chemistry 7

10 20 30 40 50 60 70

Cou

nts

0

TRD-1-2

Peak list

Goethite syn FeO(OH)

50000

100000

150000

Quartz low SiO2

Position (∘2휃) (copper (Cu))

(a)

TRD-1-5

10 20 30 40 50 60 70

Cou

nts

Peak list

0

100000

200000

Quartz low SiO2

Position (∘2휃) (copper (Cu))

(b)

Figure 1 XRPD patterns of chert samples named Trd 1-2 (a) and Trd 1-5 (b) representative of the twomineralogical compositions identified

(4thndash6th centuries) mean value 150permil All these samplesare obtained using natron from the evaporitic lakes of WadiNatron in Egypt The provenance of sand from a relativelyshort stretch of the eastern Mediterranean coast is suggestedfor the Beth Shersquoan samples and the similarity between thedelta values of the Tel el-Ashmunein and Carthage samplesis explained by their production with the same Egyptiansand The isotopic similarity among these three groups ofsamples can be explained taking into account a commonprovenance for natron and that Levantine sand comes fromEgypt and is transported up to the eastern Mediterraneancoast by sea currents [14 15] therefore the use of sandand flux with similar provenance yields glass samples withsimilar isotopic compositions The same source may thusbe hypothesised for the Greek glass samples analysed hereHowever it should be stressed that natural natron depositsin the region of Macedonia in northern Greece were well-known in the time of Plato (5th century BC) and werealso described by Pliny the Elder in his Naturalis HistoriaeHatzopoulos and Loukopoulou [16] identified Lake Chalastra(so-called in antiquity that is the place where the ldquoCha-lastraion nitronrdquo formed and dissolved over a period of afew days) as the modern lake of Picrolimni located about20 km NW of Thessaloniki The geochemical conditionsresponsible for the formation of ldquoChalastraion nitronrdquo haverecently been studied and discussed by Dotsika et al [17]The salts deposited by the lake brine were mineralogicallyidentified by XRD analysis and include not only calcite anddolomite but also trona (Na2CO3sdotNaHCO3sdot2H2O) burkeite(Na2CO3sdot2Na2SO4) and halite (NaCl) thus confirming themineralogical similarity between these deposits and thosefrom Wadi Natron in Egypt However the oxygen isotopiccompositions determined on the Picrolimni salt deposits

range from about 11 to 25permil (VSMOW) much lower than thevalues for Wadi Natron (about 34 to 40permil [2 3]) Thereforein the case of our samples use of ldquoChalastraion nitronrdquo as fluxcan hardly be considered

In contrast with the remarkable isotopic homogeneity ofthe majority of Greek samples (2939 samples) the chemicalcomposition is rather heterogeneous (Tables 2 3 and 4)although they are all obtainedwith natron as flux having bothK2O and MgO contents lower than 15 wt In particularsamples 1-1 5-1 8-1 9-1 4-3 6-4 11-4 and 14-4 fromThessaloniki (Tables 2 and 4) and all the samples fromMaroneia (Table 3) show the HIMT (High Iron Magnesiumand Titanium) signature This reference group is defined byhigh levels of iron (ge07 wt)manganese (usually sim1-2 wt)magnesium (usuallyge08 wt) and titanium (ge01 wt) andits yellow-green colour is due to the amount of iron sugges-tive of a relatively impure sand source [18] These also are thekey characteristics of Greek glass samples which have highFeO (120 plusmn 031wt) MnO (154 plusmn 035wt) MgO (124 plusmn016wt) and TiO2 (018plusmn005wt) contentsThe acronymHIMT was first applied by Freestone [19] to raw glass fromCarthage and glass vessels from Cyprus [20] although glasswith high contents of iron manganese and titanium wasalready identified by Sanderson et al [21] However all theGreek samples (except 4-3) containing about 50ndash60 of theamount of iron titanium and manganese oxides measuredin ldquotypicalrdquo HIMT glass such as Group 1 of Foy et al [22](about 121 plusmn 031wt as FeO 017 plusmn 003wt as TiO2and 151 plusmn 037wt as MnO versus 2 plusmn 08wt as FeO05 plusmn 01wt as TiO2 and 22 plusmn 04wt as MnO for Greeksamples and Group 1 resp) show a better fit with ldquoGroup 2rdquoof Foy et al [22] whichmay be considered as a ldquoweakrdquo HIMTglass [18] due to lower contents of the key oxides of HIMT

8 Journal of Chemistry

Table6Ch

emicalcompo

sitions

ofchertsam

plesn

amed

Trd1-2

andTrd1-5

representativeof

thetwomineralogicalcompo

sitions

identifi

ed(X

RFdataL

OIlosson

ignitio

n)N

otethat

GaYNbLaC

eandUcontentsaren

otrepo

rted

becausetheyarelow

erthan

XRFdetectionlim

itsfora

llsamples

(LODof

Ga=

5ppm

LODof

YNbandU=3p

pmLODof

LaandCe=

10pp

m)

Sample

SiO2

TiO2

Al 2O3

Fe2O3

MnO

MgO

CaO

Na 2O

K 2O

P 2O5

LOI

ScV

CrCo

Ni

CuZn

RbSr

ZrBa

Nd

PbTh

Num

berWt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

Trd1-2

9068

001

021

713

015

037

012

005

001

002

218

9314

507

124

146

1846

78

920

1912

7Trd1-5

9998lt00

05lt00

2lt00

05lt00

05lt00

2lt00

05lt00

2lt00

05lt00

05000lt3lt3lt3lt3lt3lt3lt3lt3lt3lt3lt10lt10lt10lt3

Journal of Chemistry 9

10 11 42 10 9 5 9 16 414

15

16

17

18

19

Number of samples

훿18O

(VSM

OW

)(permil

)

Figure 2 Comparisons among 12057518O(VSMOW) values of natron glasssamples [open symbols Thessaloniki Agora (◻) Maroneia ()Thessaloniki various sites (998779)Thessaloniki glass withmoderate 18Oenrichment (I)] and those already reported in the literature [fullsymbols Roman glass from Europe (◼) [2] Roman glass from IuliaFelix (X) [3] 4th century AD glass from Jalame (998771) [2] HIMTglass from Carthage and Levantine natron glass (bold plus sign)[12] late Antique-earlyMedieval glass fromGrado ad Vicenza (boldmultiplication sign) [3]] Number of analysed samples is also shown

glass (Figure 3) Instead sample 4-3 has FeO TiO2 andMnO contents (Table 4) perfectly comparable with ldquotypicalrdquoHIMT glass [18 22] In general HIMT glass has also beenidentified in Britain [18] Egypt [23] France [22] Italy [24ndash29] Cyprus [20 30] Carthage [31] Bulgaria [32] andAlbania[33] The chemical and isotopic signatures of HIMT glass aresuggestive of continental sand sources of high maturity richin heavy minerals and located in the Near East probablyin Egypt [12 31 34] As regards the dating of the referencegroups in general terms the HIMT group is probably morecharacteristic of the period from the mid-4th century ADonwards although according to current research its compo-sition seems to have continued after the 5th century [18]In addition according to Schibille et al [31] ldquoGroup 2rdquo isdated to the 5th-6th centuries and is thus coeval with theglass from Maroneia Consequently the age of Thessalonikiglass samples similar in composition to those of ldquoGroup 2rdquois constrained to the late Antique period

The other glass samples from Thessaloniki (2-1 3-1 6-17-1 5-3 7-3 4-4 5-4 and 7-4) whose 12057518O is in therange of ldquoRomanrdquo values also show the chemical compo-sition typical of Roman glass [35] although they differ incontents of manganese and antimony (Figure 3) and traceelements In particular samples 3-1 5-3 4-4 and 5-4 showMnO gt 05 wt which suggests its intentional addition asa decolouriser [36] whereas sample 6-1 has no manganesebut antimony (Table 2) As these two elements the principal

decolourisers used between the 1st and 4th centuries ADwere both predominant from the late 1st to the 3rd centuriesand as the use of manganese increased from the end of the3rd to the 4th century [36ndash38] the age of these samples isconstrained accordingly Instead samples 3-1 and 7-3 do notreveal any intentional addition of decolouriser having noantimony and MnO lt 05 wt (Tables 2 and 4) Sample 2-1from Thessaloniki Agora has relatively high concentrationsof CuO SnO2 PbO and P2O5 (Table 2) suggesting theinclusion of cullet perhaps coloured and opaque mosaictesserae containing high quantities of one or more of theseelements in the glass batch The chemical composition ofsample 7-1 is not far from that of sample 2-1 although the con-centrations of copper and lead are much lower than those insample 2-1 (Table 2) This indicates that the presence ofthe above elements is due to recycling of earlier colouredglass because they occur in concentrations higher than thoseattributable to impurities in the raw materials but too low tohave any technological significance [39] Conversely the highCu in sample 7-4 not associated with high Sn Co Pb Sband Zn (Table 4) suggests that this element was intentionallyadded to produce the aquamarine colour

Lastly chemical similarities between samples 4-1 and 10-1from Thessaloniki Agora and data reported in the literatureare difficult to establish Sample 4-1 seems quite comparablewith some soda-potash-lime glass from the 14th-centuryworkshop at Saint-Chely (France) Two different hypothesesboth equally valid from an analytical point of view are pro-posed to explain the peculiar chemical composition of theseLate Medieval French samples [40] both soda and potashash were used by the glass-workers soda ash remaining themain component recycled glass from the surrounding areaswith both potash and soda ash compositions was used asrawmaterials Sample 10-1 also approaches although not per-fectly the composition of ldquomixed soda-potash glassrdquo dated toLate Bronze age [40] and the oxygen isotopic data obtained byBrill et al [2] on some Late Bronze age objects are also quitecomparable with that of sample 10-1 On the contrary oxygenisotope data on samples with chemical composition similarto sample 4-1 are unfortunately still lacking although dataon Medieval soda ash and late Medieval and modern potashash glass are systematically lower and range from about 12to 145permil [2 3] In any case both isotopic and chemical datasuggest that the age proposed for samples 4-1 and 10-1 fromThessaloniki Agora should be revised

The chemical analyses of the heavily enriched glass(Table 4) show that all samples were melted with soda ashas flux their K2O MgO and P2O5 contents being higherthan those of the other samples (Figure 3) The low Al2O3content suggests that as well as flux a different silica sourcewas used to produce these samples Leslie et al [12] reportsome highly variable isotopic results from glass samples10thndash13th centuries in age from Rarsquos al-Hadd (Oman) one ofwhich is close to 20permil (Figure 4) Heavily enriched 12057518Ovalues which range from 216 to 226permil have already beenmeasured by Brill et al [2] on glass samples from Nimrud(Iraq) dated to the 7th century BC the author obviouslyconcluded that ldquothese glasses must represent a glassmaking

10 Journal of Chemistry

60 64 68 72 76 808

12

16

20N

a 2O

(wt

)

SiO2 (wt)

(a)

0 2 4 6

Natron

Soda plant ash

0

1

2

3

4

MgO

(wt

)

K2O (wt)

(b)

4 6 8 10 120

1

2

3

4

Al 2O

3 (w

t)

CaO (wt)

(c)

0 05 1 15 2 250

1

2

3

4

5

MnO

(wt

)

FeO (wt)

(d)

Figure 3 Na2O versus SiO2 (a) MgO versus K2O (b) Al2O3 versus CaO (c) and MnO versus FeO (d) contents of Greek glass samplessubdivided by provenance Thessaloniki Agora () Maroneia (I) Thessaloniki various sites (998779 natron glass 998771 soda ash glass) Meanchemical compositions and standard deviations of main compositional natron groups identified in literature and comparable with Greeksamples are also shown ldquoRomanrdquo glass (bold plus sign) Group 2 (bold multiplication sign) [22 35]

tradition thatmade use of some particular rawmaterialrdquo Twosamples from Aphrodisias (Turkey) 6th-7th centuries ADin age also yielded 12057518O values of about 234permil (Figure 4)All the samples reported in the literature with very positive12057518O values were obtained with soda ash as flux althoughthey show lowerK2OMgOandhigherNa2OK2Oratios thanGreek samples suggesting the use of different kinds of plantash

In Europe and Mediterranean area soda ash glass datesfrom the 9th century AD onwards [4 41] This wouldexclude a Roman age for Greek soda ash samples unlessthey were produced with raw glass imported from areas suchas Mesopotamia and Iran where plant ash continued to beused as flux in glass production throughout the period ofnatron dominance in the West [4] However so far chemicalcomparisons with 3rdndash7th-century soda ash glass from Iraq

Journal of Chemistry 11

7 6 2 8 6

12

16

20

24훿18O

(VSM

OW

)(permil

)

Number of samples

Figure 4 Comparisons among 12057518O(VSMOW) values of plant ash glasssamples [open symbols Thessaloniki various sites (◻)] and thosealready reported in the literature [full symbols glass from Nimrudand Aphrodisias (◼) [2] glass from Rarsquos al-Hadd (e) and Levantinesoda ash glass (X) [12] Medieval soda ash glass from Italy (998771) [3]]Number of analysed samples is also shown

[42 43] have not shown any consistency with Greek samplesIn addition the heavily enriched 12057518O values do indicatethat their raw materials differed from those normally used inRoman andMedieval glass production and this wouldmatchthe possibility of the different origin of these materials Theuse of ash as flux may cause some 18O enrichment when theash is particularly rich in carbonate bicarbonate and hydrate[4] but hardly to this extent Previous oxygen isotopic dataobtained on Medieval soda ash glass from the Western andEastern Mediterranean (Figure 4) indicate that the additionof ash did not contribute to isotopically heavy oxygen and the12057518Ovalues essentially reflect the silica source (eg [2 3 12])In the case of Greek heavily enriched glass the silica source isdifficult to identify taking into account the fact that quartzwith anomalously heavy isotopic composition is uncommoninmagmatic sedimentary or metamorphic rocks Due to thelarge oxygen isotopic fractionation between SiO2 andwater atlow temperatures biogenic silica and chert have the highest18O16O ratios observed in rocks [44] Therefore the Greeksamples with high isotopic values may be the product oflocal glass workshops which used raw materials composedof chert with the addition of ash probably obtained fromvarious plant species other than those considered by Titeet al [4] or differently pretreated The isotopic chemicaland mineralogical data obtained on a selection of chertsamples from the quarries in Triadi of Thessaloniki (CentralMacedonia Greece) furtherly support the hypothesis of localproduction at least if we consider sample Trd 1-5 composedof only quartz

In the case of samples with moderate 18O enrichmentseveral causes must be considered to explain their valuesSample 3-3 (12057518O= 186permil) has a chemical composition quiteclose to that of Roman glass decolourised by the addition ofMn [45] sample 6-3 (12057518O= 173permil) is chemically comparableto ldquoGroup 2rdquo of Foy et al [22] and its suggested age (6thcentury AD) matches the chronological diffusion of the ref-erence group However both samples have 12057518O higher thanthe average ldquoRomanrdquo or ldquoHIMTrdquo values

In view of the high Na2O content of samples 3-3 and 6-3(Table 4) 18O enrichment may be explained by remelting ofprevious glass with addition of further amounts of natron asflux which causes an increase in Na2O concentration and inthe 18O content of the final products

Apart from their slightly higher 12057518O values (161 and164permil resp) samples 3-4 and 10-4 show quite differentchemical compositions Sample 3-4 is chemically comparablewith ldquoGroup 2rdquo [22] the chronological diffusion ofwhich alsomatches the age proposed (5th-6th centuries AD) whereassample 10-4 is similar to Roman glass 1stndash3rd centuries Adin age although the presence of Cu and Pb may also indicaterecycling of coloured and opaque glass as in the case ofsample 7-1 Both samplesmay be produced in local secondaryworkshops by recycling previous glass (perhaps from theLevantine area) with the addition of further amounts ofnatron as flux as suggested by their high Na2O content(Table 4) thus increasing the 18Ocontent of the final product

According to its chemical composition sample 13-4(Table 4 12057518O= 173permil) was obtained with soda ash as flux asdeduced from its high K2O MgO and P2O5 contents Wesuggest a different starting material for this sample as in thecase of other soda plant ash glass identified in the Greekassemblage

Lastly sample 8-4 from Thessaloniki has 12057518O of 156permilthat is within the average Roman values suggesting the use ofBelus or Volturno sand and Egyptian natron as rawmaterialsbut its chemical composition is comparable to that of glassproduced with soda plant ash as flux The chronologicaldiffusion of soda ash glass in Europe andMediterranean area[4 41] excludes a Roman age for this sample and chem-ical comparisons with 3rdndash7th-century soda ash glass fromIraq [42 43] where plant ash continued to be used as fluxthroughout the period of natron dominance in the West [4]have not shown any consistency with the present sampleTherefore great uncertainty remains in the case of sample 8-4 as regards both its age and provenance also in view of theheavily enriched oxygen signatures of other soda ash samplesidentified here (Table 4) However sample 8-4 differs fromthe others due to its lower SiO2 (616 wt) and higher Al2O3(390wt) which suggest a different silica source probably asilica sand rich in feldsparsThis source may be characterisedby a less positive oxygen signature probably related to thefeldspars content of the sand which influences the 18Ocontent of the final productThis hypothesis is also supportedby the isotopic and chemical signatures of sample 13-4Obtained again with soda plant ash as flux this sample hasAl2O3 content intermediate between that of sample 8-4 andall other Greek soda ash samples and consequently shows anintermediate 12057518O value

12 Journal of Chemistry

4 Conclusions

The results of the present study emphasize the importanceof measuring the oxygen isotopic and chemical compositionsof glass samples in order to constrain some features such asage raw materials and production technology Comparisonsof our isotopic and chemical data with those reported in theliterature particularly in the case of glass from the Levantinearea are of particular interest as regards the trading ofraw glass to secondary workshops in Greece although forsome samples obtained with soda ash as flux and heavilyenriched in 18O production from local raw materials cannotbe completely excluded

In summary the thirty-nine glass samples from northernGreece studied here have oxygen isotopic compositionswhich allow them to be subdivided into three groups

The first is composed of twenty-nine samples (severalfrom Thessaloniki and all those from Maroneia) with 12057518Ovalues equal or very close to themean value of Roman glassesfrom European and Middle Eastern areas These similaritiesimply their production with raw materials with equal or veryclose oxygen isotopic composition such as sand from therivers Belus in Palestine and Volturno in Italy as suggestedby Pliny the Elder In contrast with the remarkable isotopichomogeneity heterogeneous chemical compositions allowthe subdivision of these samples into several subgroupswhich are compared with major compositional groups iden-tified in the Western Mediterranean during the first millen-nium AD

Seven samples from Thessaloniki and all the samplesfrom Maroneia show chemical similarity with ldquoGroup 2rdquo ofFoy et al [22] while one sample shows chemical simi-larity with HIMT glass Accordingly their age should beconstrained to the late Antique period for the Thessalonikiglass and confirmed for the Maroneia samples (ie 4thndash6thcenturies AD) Nine samples from Thessaloniki are chemi-cally comparable with Roman glass although they differ incolouringdecolouring elements and recycling indicators Inparticular in some samples the identification of manganeseintentionally added as a decolourant allows us to constraintheir age according to the chronological diffusion reported inthe literature of this decolourant that is from the 3rd to 4thcenturies AD Lastly three samples from Thessaloniki(1stndash6th centuries AD) with 12057518O values comparable withldquoRomanrdquo values have chemical compositions very differentfrom ldquotypicalrdquo Roman glass suggesting different productiontechnologies

The second isotopic group is composed of four samplesfrom Thessaloniki showing heavily enriched 12057518O values(205 to 227permil) their chemical analyses indicate that theywere obtained using soda ash as flux which has little effect onthe final oxygen isotopic composition of glass These high12057518O values may be explained by the use of silica rawmaterials with heavy 18O enrichment such as chert which isalso found in the Thessaloniki region Therefore these sam-ples may be the product of local glass factories

The third group is composed of five samples from Thes-saloniki showing moderate 18O enrichment (161 to 186permil)

From the chemical point of view four samples are natronglass with compositions similar to Roman or ldquoweakrdquo HIMTgroups and one is a soda ash glass In the case of natron glassthe moderate 18O enrichment may be obtained by recyclingglass (perhaps from the Levantine area) in local secondaryworkshops with the addition of further amounts of natron asflux as suggested by their high Na2O contents In the case ofsoda ash themoderate 18O enrichment with respect to otherGreek soda ash glass may be due to the use of less positivesilica source

In conclusion these interesting results the first obtainedon glass samples from northern Greece support trades andcommercial exchanges between theNear East andGreece andsuggest although further data are required to confirm it thatthe ldquofingerprintrdquo ofGreek glass production could be related tothe use of local chert and soda ash as possible raw materials

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

The authors are grateful to D Grammenos director ofthe Archaeological Museum of Thessaloniki for providingglass samples from Thessaloniki R Carampin (Istituto diGeoscienze e Georisorse Sezione di Padova CNR) F Gallo(Dipartimento dei Beni Culturali Universita di Padova) andD Pasqual (Dipartimento diGeoscienze Universita di Padova)are thanked for their kind support to execution of chemicalanalyses Financial support was provided by ldquoEx 60rdquo fundsof the University of Padova (principal investigator AlbertaSilvestri)

References

[1] R Newton andD DavisonConservation of Glass Butterworth-Heinemann Oxford UK 1999

[2] R H Brill R N Clayton T K Mayeda and C P StapletonldquoOxygen isotope analyses of early glassesrdquo in Chemical Analysesof Early Glasses R H Brill Ed vol 2 pp 303ndash322 CorningMuseum of Glass New York NY USA 1999

[3] A Silvestri A Longinelli andGMolin ldquo12057518Omeasurements ofarchaeological glass (Roman toModern age) and rawmaterialspossible interpretationrdquo Journal of Archaeological Science vol37 no 3 pp 549ndash560 2010

[4] M S Tite A Shortland Y Maniatis D Kavoussanaki and S AHarris ldquoThe composition of the soda-rich and mixed alkaliplant ashes used in the production of glassrdquo Journal of Archae-ological Science vol 33 no 9 pp 1284ndash1292 2006

[5] C Antonaras ldquoGlass working in Roman and early ChristianThessaloniki older and more recent findsrdquo in Proceedings of theHistory Technology and Conservation of Ancient Metals Glassesand Enamels International Symposium Athens Greece Novem-ber 2011

[6] I Friedman and J R OrsquoNeil ldquoCompilation of stable isotopefractionation factors of geochemical interestrdquo in Data of

Journal of Chemistry 13

Geochemistry Geological Survey Professional Paper 440-KKchapter KK 1977

[7] A Silvestri and A Marcante ldquoThe glass of Nogara (Verona) aldquowindowrdquo on production technology of mid-Medieval times inNorthern Italyrdquo Journal of Archaeological Science vol 38 no 10pp 2509ndash2522 2011

[8] S Alberta M Gianmario and P Valentina ldquoThe stained glasswindow of the southern transept of St Anthonyrsquos Basilica(Padova Italy) study of glasses and grisaille paint layersrdquoSpectrochimica ActamdashPart B Atomic Spectroscopy vol 66 no1 pp 81ndash87 2011

[9] K Govindaraju ldquoCompilation of working values and sampledescription for 383 geostandardsrdquoGeostandards Newsletter vol18 pp 1ndash158 1994

[10] A Savitzky andM J EGolay ldquoSmoothing anddifferentiation ofdata by simplified least squares proceduresrdquo Analytical Chem-istry vol 36 no 8 pp 1627ndash1639 1964

[11] J Henderson J A Evans H J Sloane M J Leng and CDoherty ldquoThe use of oxygen strontium and lead isotopesto provenance ancient glasses in the Middle Eastrdquo Journal ofArchaeological Science vol 32 no 5 pp 665ndash673 2005

[12] K A Leslie I C Freestone D Lowry and M Thirlwall ldquoTheprovenance and technology of Near Eastern glass oxygenisotopes by laser fluorination as a complement to strontiumrdquoArchaeometry vol 48 no 2 pp 253ndash270 2006

[13] R H Brill ldquoScientific investigations of the Jalame glass andrelated findsrdquo in Excavations at Jalame Site of a Glass Factory inLate Roman Palestine G D Wienberg Ed pp 257ndash293University of Missouri Press Columbia Mo USA 1988

[14] M Pomerancblum ldquoThe distribution of heavy minerals andtheir hydraulic equivalents in sediments of the Mediterraneancontinental shelf of Israelrdquo SEPM Journal of SedimentaryResearch vol 36 pp 162ndash174 1966

[15] D J Stanley Y Mart and Y Nir ldquoClay mineral distributions tointerpret Nile cell provenance and dispersal II Coastal plainfrom Nile delta to northern Israelrdquo Journal of Coastal Researchvol 13 no 2 pp 506ndash533 1997

[16] M B Hatzopoulos and L D Loukopoulou Morrylos Centrede Recherches de lrsquoAntiquite Grecque et Romaine AthenesGreece 1989

[17] E Dotsika D Poutoukis I Tzavidopoulos Y Maniatis DIgnatiadou and B Raco ldquoA natron source at Pikrolimni Lake inGreece Geochemical evidencerdquo Journal of Geochemical Explo-ration vol 103 no 2-3 pp 133ndash143 2009

[18] H E Foster and C M Jackson ldquoThe composition of ldquonaturallycolouredrdquo late Roman vessel glass from Britain and the impli-cations for models of glass production and supplyrdquo Journal ofArchaeological Science vol 36 no 2 pp 189ndash204 2009

[19] I C Freestone ldquoAppendix chemical analysis of lsquorawrsquo glass frag-mentsrdquo in Excavations at Carthage Volume II1 The CircularHarbour North SideThe Site and FindsOther than Pottery H RHurst Ed British Academy Monographs in Archaeology N∘4p 290 Oxford University Press Oxford UK 1994

[20] I C Freestone M Ponting and M J Hughes ldquoThe origins ofByzantine glass from Maroni Petrera Cyprusrdquo Archaeometryvol 44 no 2 pp 257ndash272 2002

[21] D C W Sanderson J R Hunter and S E Warren ldquoEnergydispersive X-ray fluorescence analysis of 1stmillennium ad glassfrom Britainrdquo Journal of Archaeological Science vol 11 no 1 pp53ndash69 1984

[22] D Foy M Picon M Vichy and V Thirion-Merle ldquoCar-acterisation des verres de la fin de lrsquoAntiquite en Mediterraneeoccidentale lrsquoemergence de nouveaux courants commerciauxrdquoin Echanges et Commerce du Verre dans le Monde Antique DFoy and M D Nenna Eds Actes du Colloque de lrsquoAssociationFrancaise pour lrsquoArcheologie du Verre Aix-en-Provence etMarseille June 2001 pp 41ndash85 Monique Mergoil MontagnacFrance 2003

[23] D Rosenow and T Rehren ldquoHerding cats Roman to LateAntique glass groups from Bubastis northern Egyptrdquo Journal ofArchaeological Science vol 49 no 1 pp 170ndash184 2014

[24] P Mirti A Casoli and L Appolonia ldquoScientific analysis ofroman glass from augusta praetoriardquo Archaeometry vol 35 no2 pp 225ndash240 1993

[25] A Silvestri G Molin and G Salviulo ldquoRoman and medievalglass from the Italian area bulk characterization and relation-ships with production technologiesrdquo Archaeometry vol 47 no4 pp 797ndash816 2005

[26] A Silvestri S Tonietto and G Molin ldquoThe palaeo-Christianglass mosaic of St Prosdocimus (Padova Italy) archaeometriccharacterisation of lsquogoldrsquo tesseraerdquo Journal of ArchaeologicalScience vol 38 no 12 pp 3402ndash3414 2011

[27] F Gallo and A Silvestri ldquoMedieval glass from Rocca di Asolo(northern italy) an archaeometric studyrdquoArchaeometry vol 54no 6 pp 1023ndash1039 2012

[28] F Gallo A Marcante A Silvestri and G Molin ldquoThe glass ofthe ldquoCasa delle Bestie Feriterdquo a first systematic archaeometricstudy on Late Roman vessels from Aquileiardquo Journal of Archae-ological Science vol 41 pp 7ndash20 2014

[29] S Maltoni T Chinni M Vandini E Cirelli A Silvestri andG Molin ldquoArchaeological and archaeometric study of the glassfinds from the ancient harbour of Classe (Ravenna-Italy) newevidencerdquo Heritage Science vol 3 no 1 article 13 2015

[30] A Ceglia P Cosyns K Nys H Terryn H Thienpont and WMeulebroeck ldquoLate antique glass distribution and consumptionin Cyprus a chemical studyrdquo Journal of Archaeological Sciencevol 61 pp 213ndash222 2015

[31] N Schibille A Sterrett-Krause and I C Freestone ldquoGlassgroups glass supply and recycling in late Roman CarthagerdquoArchaeological and Anthropological Sciences pp 1ndash19 2016

[32] A Cholakova T Rehren and I C Freestone ldquoCompositionalidentification of 6th c AD glass from the Lower DanuberdquoJournal of Archaeological Science Reports vol 7 pp 625ndash6322016

[33] S Conte T Chinni R Arletti and M Vandini ldquoButrint(Albania) between eastern and western Mediterranean glassproduction EMPA and LA-ICP-MS of late antique and earlymedieval findsrdquo Journal of Archaeological Science vol 49 no1 pp 6ndash20 2014

[34] I C Freestone S Wolf and M Thirlwall ldquoThe production ofHIMT glass elemental and isotopic evidencerdquo inAnnales du 16eCongres de lrsquoAssociation Internationale pour lrsquoHistoire du Verre(AIHV rsquo05) pp 153ndash157 London UK 2005

[35] M D Nenna M Picon and M Vichy ldquoAteliers primaries etsecondaries en Egypte a lrsquoepoque greco-romainerdquo in La Routedu Verre Ateliers Primaires et Secondaires du Second Millenaireav J-C au Moyen Age M D Nenna Ed vol 33 pp 97ndash112Travaux de la Maison de lrsquoOrient Mediterraneen 2000

[36] C M Jackson ldquoMaking colourless glass in the Roman periodrdquoArchaeometry vol 47 no 4 pp 763ndash780 2005

[37] E V Sayre ldquoThe intentional use of antimony and manganese inancient glassesrdquo in Advances in Glass Technology Part 2 F R

14 Journal of Chemistry

Matson and G Rindone Eds pp 263ndash282 Plenum Press NewYork NY USA 1963

[38] H E Foster and C M Jackson ldquoThe composition of lateRomano-British colourless vessel glass glass production andconsumptionrdquo Journal of Archaeological Science vol 37 no 12pp 3068ndash3080 2010

[39] J Henderson ldquoThe raw materials of early glass productionrdquoOxford Journal of Archaeology vol 4 no 3 pp 267ndash291 1985

[40] B Gratuze and K Janssens ldquoProvenance analysis of glassartefactsrdquo inNon-Destructive Microanalysis of Cultural HeritageMaterials K Janssens and R Van Grieken Eds pp 663ndash712Elsevier Amsterdam The Netherlands 2004

[41] J Henderson ldquoTradition and experiment in first millenniumAD glass productionmdashthe emergence of early Islamic glasstechnology in late antiquityrdquoAccounts of Chemical Research vol35 no 8 pp 594ndash602 2002

[42] P Mirti M Pace M M Negro Ponzi and M Aceto ldquoICP-MSanalysis of glass fragments of Parthian and Sasanian epoch fromSeleucia and Veh Ardasır (Central Iraq)rdquoArchaeometry vol 50no 3 pp 429ndash450 2008

[43] P Mirti M Pace M Malandrino and M N Ponzi ldquoSasanianglass from Veh Ardasır new evidences by ICP-MS analysisrdquoJournal of Archaeological Science vol 36 no 4 pp 1061ndash10692009

[44] J Hoefs Stable Isotope Geochemistry Springer Berlin Ger-many 5th edition 2004

[45] A Silvestri G Molin and G Salviulo ldquoThe colourless glass ofIulia Felixrdquo Journal of Archaeological Science vol 35 no 2 pp331ndash341 2008

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 201

International Journal ofInternational Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal ofInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

8 Journal of Chemistry

Table6Ch

emicalcompo

sitions

ofchertsam

plesn

amed

Trd1-2

andTrd1-5

representativeof

thetwomineralogicalcompo

sitions

identifi

ed(X

RFdataL

OIlosson

ignitio

n)N

otethat

GaYNbLaC

eandUcontentsaren

otrepo

rted

becausetheyarelow

erthan

XRFdetectionlim

itsfora

llsamples

(LODof

Ga=

5ppm

LODof

YNbandU=3p

pmLODof

LaandCe=

10pp

m)

Sample

SiO2

TiO2

Al 2O3

Fe2O3

MnO

MgO

CaO

Na 2O

K 2O

P 2O5

LOI

ScV

CrCo

Ni

CuZn

RbSr

ZrBa

Nd

PbTh

Num

berWt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

Wt

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

Trd1-2

9068

001

021

713

015

037

012

005

001

002

218

9314

507

124

146

1846

78

920

1912

7Trd1-5

9998lt00

05lt00

2lt00

05lt00

05lt00

2lt00

05lt00

2lt00

05lt00

05000lt3lt3lt3lt3lt3lt3lt3lt3lt3lt3lt10lt10lt10lt3

Journal of Chemistry 9

10 11 42 10 9 5 9 16 414

15

16

17

18

19

Number of samples

훿18O

(VSM

OW

)(permil

)

Figure 2 Comparisons among 12057518O(VSMOW) values of natron glasssamples [open symbols Thessaloniki Agora (◻) Maroneia ()Thessaloniki various sites (998779)Thessaloniki glass withmoderate 18Oenrichment (I)] and those already reported in the literature [fullsymbols Roman glass from Europe (◼) [2] Roman glass from IuliaFelix (X) [3] 4th century AD glass from Jalame (998771) [2] HIMTglass from Carthage and Levantine natron glass (bold plus sign)[12] late Antique-earlyMedieval glass fromGrado ad Vicenza (boldmultiplication sign) [3]] Number of analysed samples is also shown

glass (Figure 3) Instead sample 4-3 has FeO TiO2 andMnO contents (Table 4) perfectly comparable with ldquotypicalrdquoHIMT glass [18 22] In general HIMT glass has also beenidentified in Britain [18] Egypt [23] France [22] Italy [24ndash29] Cyprus [20 30] Carthage [31] Bulgaria [32] andAlbania[33] The chemical and isotopic signatures of HIMT glass aresuggestive of continental sand sources of high maturity richin heavy minerals and located in the Near East probablyin Egypt [12 31 34] As regards the dating of the referencegroups in general terms the HIMT group is probably morecharacteristic of the period from the mid-4th century ADonwards although according to current research its compo-sition seems to have continued after the 5th century [18]In addition according to Schibille et al [31] ldquoGroup 2rdquo isdated to the 5th-6th centuries and is thus coeval with theglass from Maroneia Consequently the age of Thessalonikiglass samples similar in composition to those of ldquoGroup 2rdquois constrained to the late Antique period

The other glass samples from Thessaloniki (2-1 3-1 6-17-1 5-3 7-3 4-4 5-4 and 7-4) whose 12057518O is in therange of ldquoRomanrdquo values also show the chemical compo-sition typical of Roman glass [35] although they differ incontents of manganese and antimony (Figure 3) and traceelements In particular samples 3-1 5-3 4-4 and 5-4 showMnO gt 05 wt which suggests its intentional addition asa decolouriser [36] whereas sample 6-1 has no manganesebut antimony (Table 2) As these two elements the principal

decolourisers used between the 1st and 4th centuries ADwere both predominant from the late 1st to the 3rd centuriesand as the use of manganese increased from the end of the3rd to the 4th century [36ndash38] the age of these samples isconstrained accordingly Instead samples 3-1 and 7-3 do notreveal any intentional addition of decolouriser having noantimony and MnO lt 05 wt (Tables 2 and 4) Sample 2-1from Thessaloniki Agora has relatively high concentrationsof CuO SnO2 PbO and P2O5 (Table 2) suggesting theinclusion of cullet perhaps coloured and opaque mosaictesserae containing high quantities of one or more of theseelements in the glass batch The chemical composition ofsample 7-1 is not far from that of sample 2-1 although the con-centrations of copper and lead are much lower than those insample 2-1 (Table 2) This indicates that the presence ofthe above elements is due to recycling of earlier colouredglass because they occur in concentrations higher than thoseattributable to impurities in the raw materials but too low tohave any technological significance [39] Conversely the highCu in sample 7-4 not associated with high Sn Co Pb Sband Zn (Table 4) suggests that this element was intentionallyadded to produce the aquamarine colour

Lastly chemical similarities between samples 4-1 and 10-1from Thessaloniki Agora and data reported in the literatureare difficult to establish Sample 4-1 seems quite comparablewith some soda-potash-lime glass from the 14th-centuryworkshop at Saint-Chely (France) Two different hypothesesboth equally valid from an analytical point of view are pro-posed to explain the peculiar chemical composition of theseLate Medieval French samples [40] both soda and potashash were used by the glass-workers soda ash remaining themain component recycled glass from the surrounding areaswith both potash and soda ash compositions was used asrawmaterials Sample 10-1 also approaches although not per-fectly the composition of ldquomixed soda-potash glassrdquo dated toLate Bronze age [40] and the oxygen isotopic data obtained byBrill et al [2] on some Late Bronze age objects are also quitecomparable with that of sample 10-1 On the contrary oxygenisotope data on samples with chemical composition similarto sample 4-1 are unfortunately still lacking although dataon Medieval soda ash and late Medieval and modern potashash glass are systematically lower and range from about 12to 145permil [2 3] In any case both isotopic and chemical datasuggest that the age proposed for samples 4-1 and 10-1 fromThessaloniki Agora should be revised

The chemical analyses of the heavily enriched glass(Table 4) show that all samples were melted with soda ashas flux their K2O MgO and P2O5 contents being higherthan those of the other samples (Figure 3) The low Al2O3content suggests that as well as flux a different silica sourcewas used to produce these samples Leslie et al [12] reportsome highly variable isotopic results from glass samples10thndash13th centuries in age from Rarsquos al-Hadd (Oman) one ofwhich is close to 20permil (Figure 4) Heavily enriched 12057518Ovalues which range from 216 to 226permil have already beenmeasured by Brill et al [2] on glass samples from Nimrud(Iraq) dated to the 7th century BC the author obviouslyconcluded that ldquothese glasses must represent a glassmaking

10 Journal of Chemistry

60 64 68 72 76 808

12

16

20N

a 2O

(wt

)

SiO2 (wt)

(a)

0 2 4 6

Natron

Soda plant ash

0

1

2

3

4

MgO

(wt

)

K2O (wt)

(b)

4 6 8 10 120

1

2

3

4

Al 2O

3 (w

t)

CaO (wt)

(c)

0 05 1 15 2 250

1

2

3

4

5

MnO

(wt

)

FeO (wt)

(d)

Figure 3 Na2O versus SiO2 (a) MgO versus K2O (b) Al2O3 versus CaO (c) and MnO versus FeO (d) contents of Greek glass samplessubdivided by provenance Thessaloniki Agora () Maroneia (I) Thessaloniki various sites (998779 natron glass 998771 soda ash glass) Meanchemical compositions and standard deviations of main compositional natron groups identified in literature and comparable with Greeksamples are also shown ldquoRomanrdquo glass (bold plus sign) Group 2 (bold multiplication sign) [22 35]

tradition thatmade use of some particular rawmaterialrdquo Twosamples from Aphrodisias (Turkey) 6th-7th centuries ADin age also yielded 12057518O values of about 234permil (Figure 4)All the samples reported in the literature with very positive12057518O values were obtained with soda ash as flux althoughthey show lowerK2OMgOandhigherNa2OK2Oratios thanGreek samples suggesting the use of different kinds of plantash

In Europe and Mediterranean area soda ash glass datesfrom the 9th century AD onwards [4 41] This wouldexclude a Roman age for Greek soda ash samples unlessthey were produced with raw glass imported from areas suchas Mesopotamia and Iran where plant ash continued to beused as flux in glass production throughout the period ofnatron dominance in the West [4] However so far chemicalcomparisons with 3rdndash7th-century soda ash glass from Iraq

Journal of Chemistry 11

7 6 2 8 6

12

16

20

24훿18O

(VSM

OW

)(permil

)

Number of samples

Figure 4 Comparisons among 12057518O(VSMOW) values of plant ash glasssamples [open symbols Thessaloniki various sites (◻)] and thosealready reported in the literature [full symbols glass from Nimrudand Aphrodisias (◼) [2] glass from Rarsquos al-Hadd (e) and Levantinesoda ash glass (X) [12] Medieval soda ash glass from Italy (998771) [3]]Number of analysed samples is also shown

[42 43] have not shown any consistency with Greek samplesIn addition the heavily enriched 12057518O values do indicatethat their raw materials differed from those normally used inRoman andMedieval glass production and this wouldmatchthe possibility of the different origin of these materials Theuse of ash as flux may cause some 18O enrichment when theash is particularly rich in carbonate bicarbonate and hydrate[4] but hardly to this extent Previous oxygen isotopic dataobtained on Medieval soda ash glass from the Western andEastern Mediterranean (Figure 4) indicate that the additionof ash did not contribute to isotopically heavy oxygen and the12057518Ovalues essentially reflect the silica source (eg [2 3 12])In the case of Greek heavily enriched glass the silica source isdifficult to identify taking into account the fact that quartzwith anomalously heavy isotopic composition is uncommoninmagmatic sedimentary or metamorphic rocks Due to thelarge oxygen isotopic fractionation between SiO2 andwater atlow temperatures biogenic silica and chert have the highest18O16O ratios observed in rocks [44] Therefore the Greeksamples with high isotopic values may be the product oflocal glass workshops which used raw materials composedof chert with the addition of ash probably obtained fromvarious plant species other than those considered by Titeet al [4] or differently pretreated The isotopic chemicaland mineralogical data obtained on a selection of chertsamples from the quarries in Triadi of Thessaloniki (CentralMacedonia Greece) furtherly support the hypothesis of localproduction at least if we consider sample Trd 1-5 composedof only quartz

In the case of samples with moderate 18O enrichmentseveral causes must be considered to explain their valuesSample 3-3 (12057518O= 186permil) has a chemical composition quiteclose to that of Roman glass decolourised by the addition ofMn [45] sample 6-3 (12057518O= 173permil) is chemically comparableto ldquoGroup 2rdquo of Foy et al [22] and its suggested age (6thcentury AD) matches the chronological diffusion of the ref-erence group However both samples have 12057518O higher thanthe average ldquoRomanrdquo or ldquoHIMTrdquo values

In view of the high Na2O content of samples 3-3 and 6-3(Table 4) 18O enrichment may be explained by remelting ofprevious glass with addition of further amounts of natron asflux which causes an increase in Na2O concentration and inthe 18O content of the final products

Apart from their slightly higher 12057518O values (161 and164permil resp) samples 3-4 and 10-4 show quite differentchemical compositions Sample 3-4 is chemically comparablewith ldquoGroup 2rdquo [22] the chronological diffusion ofwhich alsomatches the age proposed (5th-6th centuries AD) whereassample 10-4 is similar to Roman glass 1stndash3rd centuries Adin age although the presence of Cu and Pb may also indicaterecycling of coloured and opaque glass as in the case ofsample 7-1 Both samplesmay be produced in local secondaryworkshops by recycling previous glass (perhaps from theLevantine area) with the addition of further amounts ofnatron as flux as suggested by their high Na2O content(Table 4) thus increasing the 18Ocontent of the final product

According to its chemical composition sample 13-4(Table 4 12057518O= 173permil) was obtained with soda ash as flux asdeduced from its high K2O MgO and P2O5 contents Wesuggest a different starting material for this sample as in thecase of other soda plant ash glass identified in the Greekassemblage

Lastly sample 8-4 from Thessaloniki has 12057518O of 156permilthat is within the average Roman values suggesting the use ofBelus or Volturno sand and Egyptian natron as rawmaterialsbut its chemical composition is comparable to that of glassproduced with soda plant ash as flux The chronologicaldiffusion of soda ash glass in Europe andMediterranean area[4 41] excludes a Roman age for this sample and chem-ical comparisons with 3rdndash7th-century soda ash glass fromIraq [42 43] where plant ash continued to be used as fluxthroughout the period of natron dominance in the West [4]have not shown any consistency with the present sampleTherefore great uncertainty remains in the case of sample 8-4 as regards both its age and provenance also in view of theheavily enriched oxygen signatures of other soda ash samplesidentified here (Table 4) However sample 8-4 differs fromthe others due to its lower SiO2 (616 wt) and higher Al2O3(390wt) which suggest a different silica source probably asilica sand rich in feldsparsThis source may be characterisedby a less positive oxygen signature probably related to thefeldspars content of the sand which influences the 18Ocontent of the final productThis hypothesis is also supportedby the isotopic and chemical signatures of sample 13-4Obtained again with soda plant ash as flux this sample hasAl2O3 content intermediate between that of sample 8-4 andall other Greek soda ash samples and consequently shows anintermediate 12057518O value

12 Journal of Chemistry

4 Conclusions

The results of the present study emphasize the importanceof measuring the oxygen isotopic and chemical compositionsof glass samples in order to constrain some features such asage raw materials and production technology Comparisonsof our isotopic and chemical data with those reported in theliterature particularly in the case of glass from the Levantinearea are of particular interest as regards the trading ofraw glass to secondary workshops in Greece although forsome samples obtained with soda ash as flux and heavilyenriched in 18O production from local raw materials cannotbe completely excluded

In summary the thirty-nine glass samples from northernGreece studied here have oxygen isotopic compositionswhich allow them to be subdivided into three groups

The first is composed of twenty-nine samples (severalfrom Thessaloniki and all those from Maroneia) with 12057518Ovalues equal or very close to themean value of Roman glassesfrom European and Middle Eastern areas These similaritiesimply their production with raw materials with equal or veryclose oxygen isotopic composition such as sand from therivers Belus in Palestine and Volturno in Italy as suggestedby Pliny the Elder In contrast with the remarkable isotopichomogeneity heterogeneous chemical compositions allowthe subdivision of these samples into several subgroupswhich are compared with major compositional groups iden-tified in the Western Mediterranean during the first millen-nium AD

Seven samples from Thessaloniki and all the samplesfrom Maroneia show chemical similarity with ldquoGroup 2rdquo ofFoy et al [22] while one sample shows chemical simi-larity with HIMT glass Accordingly their age should beconstrained to the late Antique period for the Thessalonikiglass and confirmed for the Maroneia samples (ie 4thndash6thcenturies AD) Nine samples from Thessaloniki are chemi-cally comparable with Roman glass although they differ incolouringdecolouring elements and recycling indicators Inparticular in some samples the identification of manganeseintentionally added as a decolourant allows us to constraintheir age according to the chronological diffusion reported inthe literature of this decolourant that is from the 3rd to 4thcenturies AD Lastly three samples from Thessaloniki(1stndash6th centuries AD) with 12057518O values comparable withldquoRomanrdquo values have chemical compositions very differentfrom ldquotypicalrdquo Roman glass suggesting different productiontechnologies

The second isotopic group is composed of four samplesfrom Thessaloniki showing heavily enriched 12057518O values(205 to 227permil) their chemical analyses indicate that theywere obtained using soda ash as flux which has little effect onthe final oxygen isotopic composition of glass These high12057518O values may be explained by the use of silica rawmaterials with heavy 18O enrichment such as chert which isalso found in the Thessaloniki region Therefore these sam-ples may be the product of local glass factories

The third group is composed of five samples from Thes-saloniki showing moderate 18O enrichment (161 to 186permil)

From the chemical point of view four samples are natronglass with compositions similar to Roman or ldquoweakrdquo HIMTgroups and one is a soda ash glass In the case of natron glassthe moderate 18O enrichment may be obtained by recyclingglass (perhaps from the Levantine area) in local secondaryworkshops with the addition of further amounts of natron asflux as suggested by their high Na2O contents In the case ofsoda ash themoderate 18O enrichment with respect to otherGreek soda ash glass may be due to the use of less positivesilica source

In conclusion these interesting results the first obtainedon glass samples from northern Greece support trades andcommercial exchanges between theNear East andGreece andsuggest although further data are required to confirm it thatthe ldquofingerprintrdquo ofGreek glass production could be related tothe use of local chert and soda ash as possible raw materials

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

The authors are grateful to D Grammenos director ofthe Archaeological Museum of Thessaloniki for providingglass samples from Thessaloniki R Carampin (Istituto diGeoscienze e Georisorse Sezione di Padova CNR) F Gallo(Dipartimento dei Beni Culturali Universita di Padova) andD Pasqual (Dipartimento diGeoscienze Universita di Padova)are thanked for their kind support to execution of chemicalanalyses Financial support was provided by ldquoEx 60rdquo fundsof the University of Padova (principal investigator AlbertaSilvestri)

References

[1] R Newton andD DavisonConservation of Glass Butterworth-Heinemann Oxford UK 1999

[2] R H Brill R N Clayton T K Mayeda and C P StapletonldquoOxygen isotope analyses of early glassesrdquo in Chemical Analysesof Early Glasses R H Brill Ed vol 2 pp 303ndash322 CorningMuseum of Glass New York NY USA 1999

[3] A Silvestri A Longinelli andGMolin ldquo12057518Omeasurements ofarchaeological glass (Roman toModern age) and rawmaterialspossible interpretationrdquo Journal of Archaeological Science vol37 no 3 pp 549ndash560 2010

[4] M S Tite A Shortland Y Maniatis D Kavoussanaki and S AHarris ldquoThe composition of the soda-rich and mixed alkaliplant ashes used in the production of glassrdquo Journal of Archae-ological Science vol 33 no 9 pp 1284ndash1292 2006

[5] C Antonaras ldquoGlass working in Roman and early ChristianThessaloniki older and more recent findsrdquo in Proceedings of theHistory Technology and Conservation of Ancient Metals Glassesand Enamels International Symposium Athens Greece Novem-ber 2011

[6] I Friedman and J R OrsquoNeil ldquoCompilation of stable isotopefractionation factors of geochemical interestrdquo in Data of

Journal of Chemistry 13

Geochemistry Geological Survey Professional Paper 440-KKchapter KK 1977

[7] A Silvestri and A Marcante ldquoThe glass of Nogara (Verona) aldquowindowrdquo on production technology of mid-Medieval times inNorthern Italyrdquo Journal of Archaeological Science vol 38 no 10pp 2509ndash2522 2011

[8] S Alberta M Gianmario and P Valentina ldquoThe stained glasswindow of the southern transept of St Anthonyrsquos Basilica(Padova Italy) study of glasses and grisaille paint layersrdquoSpectrochimica ActamdashPart B Atomic Spectroscopy vol 66 no1 pp 81ndash87 2011

[9] K Govindaraju ldquoCompilation of working values and sampledescription for 383 geostandardsrdquoGeostandards Newsletter vol18 pp 1ndash158 1994

[10] A Savitzky andM J EGolay ldquoSmoothing anddifferentiation ofdata by simplified least squares proceduresrdquo Analytical Chem-istry vol 36 no 8 pp 1627ndash1639 1964

[11] J Henderson J A Evans H J Sloane M J Leng and CDoherty ldquoThe use of oxygen strontium and lead isotopesto provenance ancient glasses in the Middle Eastrdquo Journal ofArchaeological Science vol 32 no 5 pp 665ndash673 2005

[12] K A Leslie I C Freestone D Lowry and M Thirlwall ldquoTheprovenance and technology of Near Eastern glass oxygenisotopes by laser fluorination as a complement to strontiumrdquoArchaeometry vol 48 no 2 pp 253ndash270 2006

[13] R H Brill ldquoScientific investigations of the Jalame glass andrelated findsrdquo in Excavations at Jalame Site of a Glass Factory inLate Roman Palestine G D Wienberg Ed pp 257ndash293University of Missouri Press Columbia Mo USA 1988

[14] M Pomerancblum ldquoThe distribution of heavy minerals andtheir hydraulic equivalents in sediments of the Mediterraneancontinental shelf of Israelrdquo SEPM Journal of SedimentaryResearch vol 36 pp 162ndash174 1966

[15] D J Stanley Y Mart and Y Nir ldquoClay mineral distributions tointerpret Nile cell provenance and dispersal II Coastal plainfrom Nile delta to northern Israelrdquo Journal of Coastal Researchvol 13 no 2 pp 506ndash533 1997

[16] M B Hatzopoulos and L D Loukopoulou Morrylos Centrede Recherches de lrsquoAntiquite Grecque et Romaine AthenesGreece 1989

[17] E Dotsika D Poutoukis I Tzavidopoulos Y Maniatis DIgnatiadou and B Raco ldquoA natron source at Pikrolimni Lake inGreece Geochemical evidencerdquo Journal of Geochemical Explo-ration vol 103 no 2-3 pp 133ndash143 2009

[18] H E Foster and C M Jackson ldquoThe composition of ldquonaturallycolouredrdquo late Roman vessel glass from Britain and the impli-cations for models of glass production and supplyrdquo Journal ofArchaeological Science vol 36 no 2 pp 189ndash204 2009

[19] I C Freestone ldquoAppendix chemical analysis of lsquorawrsquo glass frag-mentsrdquo in Excavations at Carthage Volume II1 The CircularHarbour North SideThe Site and FindsOther than Pottery H RHurst Ed British Academy Monographs in Archaeology N∘4p 290 Oxford University Press Oxford UK 1994

[20] I C Freestone M Ponting and M J Hughes ldquoThe origins ofByzantine glass from Maroni Petrera Cyprusrdquo Archaeometryvol 44 no 2 pp 257ndash272 2002

[21] D C W Sanderson J R Hunter and S E Warren ldquoEnergydispersive X-ray fluorescence analysis of 1stmillennium ad glassfrom Britainrdquo Journal of Archaeological Science vol 11 no 1 pp53ndash69 1984

[22] D Foy M Picon M Vichy and V Thirion-Merle ldquoCar-acterisation des verres de la fin de lrsquoAntiquite en Mediterraneeoccidentale lrsquoemergence de nouveaux courants commerciauxrdquoin Echanges et Commerce du Verre dans le Monde Antique DFoy and M D Nenna Eds Actes du Colloque de lrsquoAssociationFrancaise pour lrsquoArcheologie du Verre Aix-en-Provence etMarseille June 2001 pp 41ndash85 Monique Mergoil MontagnacFrance 2003

[23] D Rosenow and T Rehren ldquoHerding cats Roman to LateAntique glass groups from Bubastis northern Egyptrdquo Journal ofArchaeological Science vol 49 no 1 pp 170ndash184 2014

[24] P Mirti A Casoli and L Appolonia ldquoScientific analysis ofroman glass from augusta praetoriardquo Archaeometry vol 35 no2 pp 225ndash240 1993

[25] A Silvestri G Molin and G Salviulo ldquoRoman and medievalglass from the Italian area bulk characterization and relation-ships with production technologiesrdquo Archaeometry vol 47 no4 pp 797ndash816 2005

[26] A Silvestri S Tonietto and G Molin ldquoThe palaeo-Christianglass mosaic of St Prosdocimus (Padova Italy) archaeometriccharacterisation of lsquogoldrsquo tesseraerdquo Journal of ArchaeologicalScience vol 38 no 12 pp 3402ndash3414 2011

[27] F Gallo and A Silvestri ldquoMedieval glass from Rocca di Asolo(northern italy) an archaeometric studyrdquoArchaeometry vol 54no 6 pp 1023ndash1039 2012

[28] F Gallo A Marcante A Silvestri and G Molin ldquoThe glass ofthe ldquoCasa delle Bestie Feriterdquo a first systematic archaeometricstudy on Late Roman vessels from Aquileiardquo Journal of Archae-ological Science vol 41 pp 7ndash20 2014

[29] S Maltoni T Chinni M Vandini E Cirelli A Silvestri andG Molin ldquoArchaeological and archaeometric study of the glassfinds from the ancient harbour of Classe (Ravenna-Italy) newevidencerdquo Heritage Science vol 3 no 1 article 13 2015

[30] A Ceglia P Cosyns K Nys H Terryn H Thienpont and WMeulebroeck ldquoLate antique glass distribution and consumptionin Cyprus a chemical studyrdquo Journal of Archaeological Sciencevol 61 pp 213ndash222 2015

[31] N Schibille A Sterrett-Krause and I C Freestone ldquoGlassgroups glass supply and recycling in late Roman CarthagerdquoArchaeological and Anthropological Sciences pp 1ndash19 2016

[32] A Cholakova T Rehren and I C Freestone ldquoCompositionalidentification of 6th c AD glass from the Lower DanuberdquoJournal of Archaeological Science Reports vol 7 pp 625ndash6322016

[33] S Conte T Chinni R Arletti and M Vandini ldquoButrint(Albania) between eastern and western Mediterranean glassproduction EMPA and LA-ICP-MS of late antique and earlymedieval findsrdquo Journal of Archaeological Science vol 49 no1 pp 6ndash20 2014

[34] I C Freestone S Wolf and M Thirlwall ldquoThe production ofHIMT glass elemental and isotopic evidencerdquo inAnnales du 16eCongres de lrsquoAssociation Internationale pour lrsquoHistoire du Verre(AIHV rsquo05) pp 153ndash157 London UK 2005

[35] M D Nenna M Picon and M Vichy ldquoAteliers primaries etsecondaries en Egypte a lrsquoepoque greco-romainerdquo in La Routedu Verre Ateliers Primaires et Secondaires du Second Millenaireav J-C au Moyen Age M D Nenna Ed vol 33 pp 97ndash112Travaux de la Maison de lrsquoOrient Mediterraneen 2000

[36] C M Jackson ldquoMaking colourless glass in the Roman periodrdquoArchaeometry vol 47 no 4 pp 763ndash780 2005

[37] E V Sayre ldquoThe intentional use of antimony and manganese inancient glassesrdquo in Advances in Glass Technology Part 2 F R

14 Journal of Chemistry

Matson and G Rindone Eds pp 263ndash282 Plenum Press NewYork NY USA 1963

[38] H E Foster and C M Jackson ldquoThe composition of lateRomano-British colourless vessel glass glass production andconsumptionrdquo Journal of Archaeological Science vol 37 no 12pp 3068ndash3080 2010

[39] J Henderson ldquoThe raw materials of early glass productionrdquoOxford Journal of Archaeology vol 4 no 3 pp 267ndash291 1985

[40] B Gratuze and K Janssens ldquoProvenance analysis of glassartefactsrdquo inNon-Destructive Microanalysis of Cultural HeritageMaterials K Janssens and R Van Grieken Eds pp 663ndash712Elsevier Amsterdam The Netherlands 2004

[41] J Henderson ldquoTradition and experiment in first millenniumAD glass productionmdashthe emergence of early Islamic glasstechnology in late antiquityrdquoAccounts of Chemical Research vol35 no 8 pp 594ndash602 2002

[42] P Mirti M Pace M M Negro Ponzi and M Aceto ldquoICP-MSanalysis of glass fragments of Parthian and Sasanian epoch fromSeleucia and Veh Ardasır (Central Iraq)rdquoArchaeometry vol 50no 3 pp 429ndash450 2008

[43] P Mirti M Pace M Malandrino and M N Ponzi ldquoSasanianglass from Veh Ardasır new evidences by ICP-MS analysisrdquoJournal of Archaeological Science vol 36 no 4 pp 1061ndash10692009

[44] J Hoefs Stable Isotope Geochemistry Springer Berlin Ger-many 5th edition 2004

[45] A Silvestri G Molin and G Salviulo ldquoThe colourless glass ofIulia Felixrdquo Journal of Archaeological Science vol 35 no 2 pp331ndash341 2008

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 201

International Journal ofInternational Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal ofInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Journal of Chemistry 9

10 11 42 10 9 5 9 16 414

15

16

17

18

19

Number of samples

훿18O

(VSM

OW

)(permil

)

Figure 2 Comparisons among 12057518O(VSMOW) values of natron glasssamples [open symbols Thessaloniki Agora (◻) Maroneia ()Thessaloniki various sites (998779)Thessaloniki glass withmoderate 18Oenrichment (I)] and those already reported in the literature [fullsymbols Roman glass from Europe (◼) [2] Roman glass from IuliaFelix (X) [3] 4th century AD glass from Jalame (998771) [2] HIMTglass from Carthage and Levantine natron glass (bold plus sign)[12] late Antique-earlyMedieval glass fromGrado ad Vicenza (boldmultiplication sign) [3]] Number of analysed samples is also shown

glass (Figure 3) Instead sample 4-3 has FeO TiO2 andMnO contents (Table 4) perfectly comparable with ldquotypicalrdquoHIMT glass [18 22] In general HIMT glass has also beenidentified in Britain [18] Egypt [23] France [22] Italy [24ndash29] Cyprus [20 30] Carthage [31] Bulgaria [32] andAlbania[33] The chemical and isotopic signatures of HIMT glass aresuggestive of continental sand sources of high maturity richin heavy minerals and located in the Near East probablyin Egypt [12 31 34] As regards the dating of the referencegroups in general terms the HIMT group is probably morecharacteristic of the period from the mid-4th century ADonwards although according to current research its compo-sition seems to have continued after the 5th century [18]In addition according to Schibille et al [31] ldquoGroup 2rdquo isdated to the 5th-6th centuries and is thus coeval with theglass from Maroneia Consequently the age of Thessalonikiglass samples similar in composition to those of ldquoGroup 2rdquois constrained to the late Antique period

The other glass samples from Thessaloniki (2-1 3-1 6-17-1 5-3 7-3 4-4 5-4 and 7-4) whose 12057518O is in therange of ldquoRomanrdquo values also show the chemical compo-sition typical of Roman glass [35] although they differ incontents of manganese and antimony (Figure 3) and traceelements In particular samples 3-1 5-3 4-4 and 5-4 showMnO gt 05 wt which suggests its intentional addition asa decolouriser [36] whereas sample 6-1 has no manganesebut antimony (Table 2) As these two elements the principal

decolourisers used between the 1st and 4th centuries ADwere both predominant from the late 1st to the 3rd centuriesand as the use of manganese increased from the end of the3rd to the 4th century [36ndash38] the age of these samples isconstrained accordingly Instead samples 3-1 and 7-3 do notreveal any intentional addition of decolouriser having noantimony and MnO lt 05 wt (Tables 2 and 4) Sample 2-1from Thessaloniki Agora has relatively high concentrationsof CuO SnO2 PbO and P2O5 (Table 2) suggesting theinclusion of cullet perhaps coloured and opaque mosaictesserae containing high quantities of one or more of theseelements in the glass batch The chemical composition ofsample 7-1 is not far from that of sample 2-1 although the con-centrations of copper and lead are much lower than those insample 2-1 (Table 2) This indicates that the presence ofthe above elements is due to recycling of earlier colouredglass because they occur in concentrations higher than thoseattributable to impurities in the raw materials but too low tohave any technological significance [39] Conversely the highCu in sample 7-4 not associated with high Sn Co Pb Sband Zn (Table 4) suggests that this element was intentionallyadded to produce the aquamarine colour

Lastly chemical similarities between samples 4-1 and 10-1from Thessaloniki Agora and data reported in the literatureare difficult to establish Sample 4-1 seems quite comparablewith some soda-potash-lime glass from the 14th-centuryworkshop at Saint-Chely (France) Two different hypothesesboth equally valid from an analytical point of view are pro-posed to explain the peculiar chemical composition of theseLate Medieval French samples [40] both soda and potashash were used by the glass-workers soda ash remaining themain component recycled glass from the surrounding areaswith both potash and soda ash compositions was used asrawmaterials Sample 10-1 also approaches although not per-fectly the composition of ldquomixed soda-potash glassrdquo dated toLate Bronze age [40] and the oxygen isotopic data obtained byBrill et al [2] on some Late Bronze age objects are also quitecomparable with that of sample 10-1 On the contrary oxygenisotope data on samples with chemical composition similarto sample 4-1 are unfortunately still lacking although dataon Medieval soda ash and late Medieval and modern potashash glass are systematically lower and range from about 12to 145permil [2 3] In any case both isotopic and chemical datasuggest that the age proposed for samples 4-1 and 10-1 fromThessaloniki Agora should be revised

The chemical analyses of the heavily enriched glass(Table 4) show that all samples were melted with soda ashas flux their K2O MgO and P2O5 contents being higherthan those of the other samples (Figure 3) The low Al2O3content suggests that as well as flux a different silica sourcewas used to produce these samples Leslie et al [12] reportsome highly variable isotopic results from glass samples10thndash13th centuries in age from Rarsquos al-Hadd (Oman) one ofwhich is close to 20permil (Figure 4) Heavily enriched 12057518Ovalues which range from 216 to 226permil have already beenmeasured by Brill et al [2] on glass samples from Nimrud(Iraq) dated to the 7th century BC the author obviouslyconcluded that ldquothese glasses must represent a glassmaking

10 Journal of Chemistry

60 64 68 72 76 808

12

16

20N

a 2O

(wt

)

SiO2 (wt)

(a)

0 2 4 6

Natron

Soda plant ash

0

1

2

3

4

MgO

(wt

)

K2O (wt)

(b)

4 6 8 10 120

1

2

3

4

Al 2O

3 (w

t)

CaO (wt)

(c)

0 05 1 15 2 250

1

2

3

4

5

MnO

(wt

)

FeO (wt)

(d)

Figure 3 Na2O versus SiO2 (a) MgO versus K2O (b) Al2O3 versus CaO (c) and MnO versus FeO (d) contents of Greek glass samplessubdivided by provenance Thessaloniki Agora () Maroneia (I) Thessaloniki various sites (998779 natron glass 998771 soda ash glass) Meanchemical compositions and standard deviations of main compositional natron groups identified in literature and comparable with Greeksamples are also shown ldquoRomanrdquo glass (bold plus sign) Group 2 (bold multiplication sign) [22 35]

tradition thatmade use of some particular rawmaterialrdquo Twosamples from Aphrodisias (Turkey) 6th-7th centuries ADin age also yielded 12057518O values of about 234permil (Figure 4)All the samples reported in the literature with very positive12057518O values were obtained with soda ash as flux althoughthey show lowerK2OMgOandhigherNa2OK2Oratios thanGreek samples suggesting the use of different kinds of plantash

In Europe and Mediterranean area soda ash glass datesfrom the 9th century AD onwards [4 41] This wouldexclude a Roman age for Greek soda ash samples unlessthey were produced with raw glass imported from areas suchas Mesopotamia and Iran where plant ash continued to beused as flux in glass production throughout the period ofnatron dominance in the West [4] However so far chemicalcomparisons with 3rdndash7th-century soda ash glass from Iraq

Journal of Chemistry 11

7 6 2 8 6

12

16

20

24훿18O

(VSM

OW

)(permil

)

Number of samples

Figure 4 Comparisons among 12057518O(VSMOW) values of plant ash glasssamples [open symbols Thessaloniki various sites (◻)] and thosealready reported in the literature [full symbols glass from Nimrudand Aphrodisias (◼) [2] glass from Rarsquos al-Hadd (e) and Levantinesoda ash glass (X) [12] Medieval soda ash glass from Italy (998771) [3]]Number of analysed samples is also shown

[42 43] have not shown any consistency with Greek samplesIn addition the heavily enriched 12057518O values do indicatethat their raw materials differed from those normally used inRoman andMedieval glass production and this wouldmatchthe possibility of the different origin of these materials Theuse of ash as flux may cause some 18O enrichment when theash is particularly rich in carbonate bicarbonate and hydrate[4] but hardly to this extent Previous oxygen isotopic dataobtained on Medieval soda ash glass from the Western andEastern Mediterranean (Figure 4) indicate that the additionof ash did not contribute to isotopically heavy oxygen and the12057518Ovalues essentially reflect the silica source (eg [2 3 12])In the case of Greek heavily enriched glass the silica source isdifficult to identify taking into account the fact that quartzwith anomalously heavy isotopic composition is uncommoninmagmatic sedimentary or metamorphic rocks Due to thelarge oxygen isotopic fractionation between SiO2 andwater atlow temperatures biogenic silica and chert have the highest18O16O ratios observed in rocks [44] Therefore the Greeksamples with high isotopic values may be the product oflocal glass workshops which used raw materials composedof chert with the addition of ash probably obtained fromvarious plant species other than those considered by Titeet al [4] or differently pretreated The isotopic chemicaland mineralogical data obtained on a selection of chertsamples from the quarries in Triadi of Thessaloniki (CentralMacedonia Greece) furtherly support the hypothesis of localproduction at least if we consider sample Trd 1-5 composedof only quartz

In the case of samples with moderate 18O enrichmentseveral causes must be considered to explain their valuesSample 3-3 (12057518O= 186permil) has a chemical composition quiteclose to that of Roman glass decolourised by the addition ofMn [45] sample 6-3 (12057518O= 173permil) is chemically comparableto ldquoGroup 2rdquo of Foy et al [22] and its suggested age (6thcentury AD) matches the chronological diffusion of the ref-erence group However both samples have 12057518O higher thanthe average ldquoRomanrdquo or ldquoHIMTrdquo values

In view of the high Na2O content of samples 3-3 and 6-3(Table 4) 18O enrichment may be explained by remelting ofprevious glass with addition of further amounts of natron asflux which causes an increase in Na2O concentration and inthe 18O content of the final products

Apart from their slightly higher 12057518O values (161 and164permil resp) samples 3-4 and 10-4 show quite differentchemical compositions Sample 3-4 is chemically comparablewith ldquoGroup 2rdquo [22] the chronological diffusion ofwhich alsomatches the age proposed (5th-6th centuries AD) whereassample 10-4 is similar to Roman glass 1stndash3rd centuries Adin age although the presence of Cu and Pb may also indicaterecycling of coloured and opaque glass as in the case ofsample 7-1 Both samplesmay be produced in local secondaryworkshops by recycling previous glass (perhaps from theLevantine area) with the addition of further amounts ofnatron as flux as suggested by their high Na2O content(Table 4) thus increasing the 18Ocontent of the final product

According to its chemical composition sample 13-4(Table 4 12057518O= 173permil) was obtained with soda ash as flux asdeduced from its high K2O MgO and P2O5 contents Wesuggest a different starting material for this sample as in thecase of other soda plant ash glass identified in the Greekassemblage

Lastly sample 8-4 from Thessaloniki has 12057518O of 156permilthat is within the average Roman values suggesting the use ofBelus or Volturno sand and Egyptian natron as rawmaterialsbut its chemical composition is comparable to that of glassproduced with soda plant ash as flux The chronologicaldiffusion of soda ash glass in Europe andMediterranean area[4 41] excludes a Roman age for this sample and chem-ical comparisons with 3rdndash7th-century soda ash glass fromIraq [42 43] where plant ash continued to be used as fluxthroughout the period of natron dominance in the West [4]have not shown any consistency with the present sampleTherefore great uncertainty remains in the case of sample 8-4 as regards both its age and provenance also in view of theheavily enriched oxygen signatures of other soda ash samplesidentified here (Table 4) However sample 8-4 differs fromthe others due to its lower SiO2 (616 wt) and higher Al2O3(390wt) which suggest a different silica source probably asilica sand rich in feldsparsThis source may be characterisedby a less positive oxygen signature probably related to thefeldspars content of the sand which influences the 18Ocontent of the final productThis hypothesis is also supportedby the isotopic and chemical signatures of sample 13-4Obtained again with soda plant ash as flux this sample hasAl2O3 content intermediate between that of sample 8-4 andall other Greek soda ash samples and consequently shows anintermediate 12057518O value

12 Journal of Chemistry

4 Conclusions

The results of the present study emphasize the importanceof measuring the oxygen isotopic and chemical compositionsof glass samples in order to constrain some features such asage raw materials and production technology Comparisonsof our isotopic and chemical data with those reported in theliterature particularly in the case of glass from the Levantinearea are of particular interest as regards the trading ofraw glass to secondary workshops in Greece although forsome samples obtained with soda ash as flux and heavilyenriched in 18O production from local raw materials cannotbe completely excluded

In summary the thirty-nine glass samples from northernGreece studied here have oxygen isotopic compositionswhich allow them to be subdivided into three groups

The first is composed of twenty-nine samples (severalfrom Thessaloniki and all those from Maroneia) with 12057518Ovalues equal or very close to themean value of Roman glassesfrom European and Middle Eastern areas These similaritiesimply their production with raw materials with equal or veryclose oxygen isotopic composition such as sand from therivers Belus in Palestine and Volturno in Italy as suggestedby Pliny the Elder In contrast with the remarkable isotopichomogeneity heterogeneous chemical compositions allowthe subdivision of these samples into several subgroupswhich are compared with major compositional groups iden-tified in the Western Mediterranean during the first millen-nium AD

Seven samples from Thessaloniki and all the samplesfrom Maroneia show chemical similarity with ldquoGroup 2rdquo ofFoy et al [22] while one sample shows chemical simi-larity with HIMT glass Accordingly their age should beconstrained to the late Antique period for the Thessalonikiglass and confirmed for the Maroneia samples (ie 4thndash6thcenturies AD) Nine samples from Thessaloniki are chemi-cally comparable with Roman glass although they differ incolouringdecolouring elements and recycling indicators Inparticular in some samples the identification of manganeseintentionally added as a decolourant allows us to constraintheir age according to the chronological diffusion reported inthe literature of this decolourant that is from the 3rd to 4thcenturies AD Lastly three samples from Thessaloniki(1stndash6th centuries AD) with 12057518O values comparable withldquoRomanrdquo values have chemical compositions very differentfrom ldquotypicalrdquo Roman glass suggesting different productiontechnologies

The second isotopic group is composed of four samplesfrom Thessaloniki showing heavily enriched 12057518O values(205 to 227permil) their chemical analyses indicate that theywere obtained using soda ash as flux which has little effect onthe final oxygen isotopic composition of glass These high12057518O values may be explained by the use of silica rawmaterials with heavy 18O enrichment such as chert which isalso found in the Thessaloniki region Therefore these sam-ples may be the product of local glass factories

The third group is composed of five samples from Thes-saloniki showing moderate 18O enrichment (161 to 186permil)

From the chemical point of view four samples are natronglass with compositions similar to Roman or ldquoweakrdquo HIMTgroups and one is a soda ash glass In the case of natron glassthe moderate 18O enrichment may be obtained by recyclingglass (perhaps from the Levantine area) in local secondaryworkshops with the addition of further amounts of natron asflux as suggested by their high Na2O contents In the case ofsoda ash themoderate 18O enrichment with respect to otherGreek soda ash glass may be due to the use of less positivesilica source

In conclusion these interesting results the first obtainedon glass samples from northern Greece support trades andcommercial exchanges between theNear East andGreece andsuggest although further data are required to confirm it thatthe ldquofingerprintrdquo ofGreek glass production could be related tothe use of local chert and soda ash as possible raw materials

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

The authors are grateful to D Grammenos director ofthe Archaeological Museum of Thessaloniki for providingglass samples from Thessaloniki R Carampin (Istituto diGeoscienze e Georisorse Sezione di Padova CNR) F Gallo(Dipartimento dei Beni Culturali Universita di Padova) andD Pasqual (Dipartimento diGeoscienze Universita di Padova)are thanked for their kind support to execution of chemicalanalyses Financial support was provided by ldquoEx 60rdquo fundsof the University of Padova (principal investigator AlbertaSilvestri)

References

[1] R Newton andD DavisonConservation of Glass Butterworth-Heinemann Oxford UK 1999

[2] R H Brill R N Clayton T K Mayeda and C P StapletonldquoOxygen isotope analyses of early glassesrdquo in Chemical Analysesof Early Glasses R H Brill Ed vol 2 pp 303ndash322 CorningMuseum of Glass New York NY USA 1999

[3] A Silvestri A Longinelli andGMolin ldquo12057518Omeasurements ofarchaeological glass (Roman toModern age) and rawmaterialspossible interpretationrdquo Journal of Archaeological Science vol37 no 3 pp 549ndash560 2010

[4] M S Tite A Shortland Y Maniatis D Kavoussanaki and S AHarris ldquoThe composition of the soda-rich and mixed alkaliplant ashes used in the production of glassrdquo Journal of Archae-ological Science vol 33 no 9 pp 1284ndash1292 2006

[5] C Antonaras ldquoGlass working in Roman and early ChristianThessaloniki older and more recent findsrdquo in Proceedings of theHistory Technology and Conservation of Ancient Metals Glassesand Enamels International Symposium Athens Greece Novem-ber 2011

[6] I Friedman and J R OrsquoNeil ldquoCompilation of stable isotopefractionation factors of geochemical interestrdquo in Data of

Journal of Chemistry 13

Geochemistry Geological Survey Professional Paper 440-KKchapter KK 1977

[7] A Silvestri and A Marcante ldquoThe glass of Nogara (Verona) aldquowindowrdquo on production technology of mid-Medieval times inNorthern Italyrdquo Journal of Archaeological Science vol 38 no 10pp 2509ndash2522 2011

[8] S Alberta M Gianmario and P Valentina ldquoThe stained glasswindow of the southern transept of St Anthonyrsquos Basilica(Padova Italy) study of glasses and grisaille paint layersrdquoSpectrochimica ActamdashPart B Atomic Spectroscopy vol 66 no1 pp 81ndash87 2011

[9] K Govindaraju ldquoCompilation of working values and sampledescription for 383 geostandardsrdquoGeostandards Newsletter vol18 pp 1ndash158 1994

[10] A Savitzky andM J EGolay ldquoSmoothing anddifferentiation ofdata by simplified least squares proceduresrdquo Analytical Chem-istry vol 36 no 8 pp 1627ndash1639 1964

[11] J Henderson J A Evans H J Sloane M J Leng and CDoherty ldquoThe use of oxygen strontium and lead isotopesto provenance ancient glasses in the Middle Eastrdquo Journal ofArchaeological Science vol 32 no 5 pp 665ndash673 2005

[12] K A Leslie I C Freestone D Lowry and M Thirlwall ldquoTheprovenance and technology of Near Eastern glass oxygenisotopes by laser fluorination as a complement to strontiumrdquoArchaeometry vol 48 no 2 pp 253ndash270 2006

[13] R H Brill ldquoScientific investigations of the Jalame glass andrelated findsrdquo in Excavations at Jalame Site of a Glass Factory inLate Roman Palestine G D Wienberg Ed pp 257ndash293University of Missouri Press Columbia Mo USA 1988

[14] M Pomerancblum ldquoThe distribution of heavy minerals andtheir hydraulic equivalents in sediments of the Mediterraneancontinental shelf of Israelrdquo SEPM Journal of SedimentaryResearch vol 36 pp 162ndash174 1966

[15] D J Stanley Y Mart and Y Nir ldquoClay mineral distributions tointerpret Nile cell provenance and dispersal II Coastal plainfrom Nile delta to northern Israelrdquo Journal of Coastal Researchvol 13 no 2 pp 506ndash533 1997

[16] M B Hatzopoulos and L D Loukopoulou Morrylos Centrede Recherches de lrsquoAntiquite Grecque et Romaine AthenesGreece 1989

[17] E Dotsika D Poutoukis I Tzavidopoulos Y Maniatis DIgnatiadou and B Raco ldquoA natron source at Pikrolimni Lake inGreece Geochemical evidencerdquo Journal of Geochemical Explo-ration vol 103 no 2-3 pp 133ndash143 2009

[18] H E Foster and C M Jackson ldquoThe composition of ldquonaturallycolouredrdquo late Roman vessel glass from Britain and the impli-cations for models of glass production and supplyrdquo Journal ofArchaeological Science vol 36 no 2 pp 189ndash204 2009

[19] I C Freestone ldquoAppendix chemical analysis of lsquorawrsquo glass frag-mentsrdquo in Excavations at Carthage Volume II1 The CircularHarbour North SideThe Site and FindsOther than Pottery H RHurst Ed British Academy Monographs in Archaeology N∘4p 290 Oxford University Press Oxford UK 1994

[20] I C Freestone M Ponting and M J Hughes ldquoThe origins ofByzantine glass from Maroni Petrera Cyprusrdquo Archaeometryvol 44 no 2 pp 257ndash272 2002

[21] D C W Sanderson J R Hunter and S E Warren ldquoEnergydispersive X-ray fluorescence analysis of 1stmillennium ad glassfrom Britainrdquo Journal of Archaeological Science vol 11 no 1 pp53ndash69 1984

[22] D Foy M Picon M Vichy and V Thirion-Merle ldquoCar-acterisation des verres de la fin de lrsquoAntiquite en Mediterraneeoccidentale lrsquoemergence de nouveaux courants commerciauxrdquoin Echanges et Commerce du Verre dans le Monde Antique DFoy and M D Nenna Eds Actes du Colloque de lrsquoAssociationFrancaise pour lrsquoArcheologie du Verre Aix-en-Provence etMarseille June 2001 pp 41ndash85 Monique Mergoil MontagnacFrance 2003

[23] D Rosenow and T Rehren ldquoHerding cats Roman to LateAntique glass groups from Bubastis northern Egyptrdquo Journal ofArchaeological Science vol 49 no 1 pp 170ndash184 2014

[24] P Mirti A Casoli and L Appolonia ldquoScientific analysis ofroman glass from augusta praetoriardquo Archaeometry vol 35 no2 pp 225ndash240 1993

[25] A Silvestri G Molin and G Salviulo ldquoRoman and medievalglass from the Italian area bulk characterization and relation-ships with production technologiesrdquo Archaeometry vol 47 no4 pp 797ndash816 2005

[26] A Silvestri S Tonietto and G Molin ldquoThe palaeo-Christianglass mosaic of St Prosdocimus (Padova Italy) archaeometriccharacterisation of lsquogoldrsquo tesseraerdquo Journal of ArchaeologicalScience vol 38 no 12 pp 3402ndash3414 2011

[27] F Gallo and A Silvestri ldquoMedieval glass from Rocca di Asolo(northern italy) an archaeometric studyrdquoArchaeometry vol 54no 6 pp 1023ndash1039 2012

[28] F Gallo A Marcante A Silvestri and G Molin ldquoThe glass ofthe ldquoCasa delle Bestie Feriterdquo a first systematic archaeometricstudy on Late Roman vessels from Aquileiardquo Journal of Archae-ological Science vol 41 pp 7ndash20 2014

[29] S Maltoni T Chinni M Vandini E Cirelli A Silvestri andG Molin ldquoArchaeological and archaeometric study of the glassfinds from the ancient harbour of Classe (Ravenna-Italy) newevidencerdquo Heritage Science vol 3 no 1 article 13 2015

[30] A Ceglia P Cosyns K Nys H Terryn H Thienpont and WMeulebroeck ldquoLate antique glass distribution and consumptionin Cyprus a chemical studyrdquo Journal of Archaeological Sciencevol 61 pp 213ndash222 2015

[31] N Schibille A Sterrett-Krause and I C Freestone ldquoGlassgroups glass supply and recycling in late Roman CarthagerdquoArchaeological and Anthropological Sciences pp 1ndash19 2016

[32] A Cholakova T Rehren and I C Freestone ldquoCompositionalidentification of 6th c AD glass from the Lower DanuberdquoJournal of Archaeological Science Reports vol 7 pp 625ndash6322016

[33] S Conte T Chinni R Arletti and M Vandini ldquoButrint(Albania) between eastern and western Mediterranean glassproduction EMPA and LA-ICP-MS of late antique and earlymedieval findsrdquo Journal of Archaeological Science vol 49 no1 pp 6ndash20 2014

[34] I C Freestone S Wolf and M Thirlwall ldquoThe production ofHIMT glass elemental and isotopic evidencerdquo inAnnales du 16eCongres de lrsquoAssociation Internationale pour lrsquoHistoire du Verre(AIHV rsquo05) pp 153ndash157 London UK 2005

[35] M D Nenna M Picon and M Vichy ldquoAteliers primaries etsecondaries en Egypte a lrsquoepoque greco-romainerdquo in La Routedu Verre Ateliers Primaires et Secondaires du Second Millenaireav J-C au Moyen Age M D Nenna Ed vol 33 pp 97ndash112Travaux de la Maison de lrsquoOrient Mediterraneen 2000

[36] C M Jackson ldquoMaking colourless glass in the Roman periodrdquoArchaeometry vol 47 no 4 pp 763ndash780 2005

[37] E V Sayre ldquoThe intentional use of antimony and manganese inancient glassesrdquo in Advances in Glass Technology Part 2 F R

14 Journal of Chemistry

Matson and G Rindone Eds pp 263ndash282 Plenum Press NewYork NY USA 1963

[38] H E Foster and C M Jackson ldquoThe composition of lateRomano-British colourless vessel glass glass production andconsumptionrdquo Journal of Archaeological Science vol 37 no 12pp 3068ndash3080 2010

[39] J Henderson ldquoThe raw materials of early glass productionrdquoOxford Journal of Archaeology vol 4 no 3 pp 267ndash291 1985

[40] B Gratuze and K Janssens ldquoProvenance analysis of glassartefactsrdquo inNon-Destructive Microanalysis of Cultural HeritageMaterials K Janssens and R Van Grieken Eds pp 663ndash712Elsevier Amsterdam The Netherlands 2004

[41] J Henderson ldquoTradition and experiment in first millenniumAD glass productionmdashthe emergence of early Islamic glasstechnology in late antiquityrdquoAccounts of Chemical Research vol35 no 8 pp 594ndash602 2002

[42] P Mirti M Pace M M Negro Ponzi and M Aceto ldquoICP-MSanalysis of glass fragments of Parthian and Sasanian epoch fromSeleucia and Veh Ardasır (Central Iraq)rdquoArchaeometry vol 50no 3 pp 429ndash450 2008

[43] P Mirti M Pace M Malandrino and M N Ponzi ldquoSasanianglass from Veh Ardasır new evidences by ICP-MS analysisrdquoJournal of Archaeological Science vol 36 no 4 pp 1061ndash10692009

[44] J Hoefs Stable Isotope Geochemistry Springer Berlin Ger-many 5th edition 2004

[45] A Silvestri G Molin and G Salviulo ldquoThe colourless glass ofIulia Felixrdquo Journal of Archaeological Science vol 35 no 2 pp331ndash341 2008

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 201

International Journal ofInternational Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal ofInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

10 Journal of Chemistry

60 64 68 72 76 808

12

16

20N

a 2O

(wt

)

SiO2 (wt)

(a)

0 2 4 6

Natron

Soda plant ash

0

1

2

3

4

MgO

(wt

)

K2O (wt)

(b)

4 6 8 10 120

1

2

3

4

Al 2O

3 (w

t)

CaO (wt)

(c)

0 05 1 15 2 250

1

2

3

4

5

MnO

(wt

)

FeO (wt)

(d)

Figure 3 Na2O versus SiO2 (a) MgO versus K2O (b) Al2O3 versus CaO (c) and MnO versus FeO (d) contents of Greek glass samplessubdivided by provenance Thessaloniki Agora () Maroneia (I) Thessaloniki various sites (998779 natron glass 998771 soda ash glass) Meanchemical compositions and standard deviations of main compositional natron groups identified in literature and comparable with Greeksamples are also shown ldquoRomanrdquo glass (bold plus sign) Group 2 (bold multiplication sign) [22 35]

tradition thatmade use of some particular rawmaterialrdquo Twosamples from Aphrodisias (Turkey) 6th-7th centuries ADin age also yielded 12057518O values of about 234permil (Figure 4)All the samples reported in the literature with very positive12057518O values were obtained with soda ash as flux althoughthey show lowerK2OMgOandhigherNa2OK2Oratios thanGreek samples suggesting the use of different kinds of plantash

In Europe and Mediterranean area soda ash glass datesfrom the 9th century AD onwards [4 41] This wouldexclude a Roman age for Greek soda ash samples unlessthey were produced with raw glass imported from areas suchas Mesopotamia and Iran where plant ash continued to beused as flux in glass production throughout the period ofnatron dominance in the West [4] However so far chemicalcomparisons with 3rdndash7th-century soda ash glass from Iraq

Journal of Chemistry 11

7 6 2 8 6

12

16

20

24훿18O

(VSM

OW

)(permil

)

Number of samples

Figure 4 Comparisons among 12057518O(VSMOW) values of plant ash glasssamples [open symbols Thessaloniki various sites (◻)] and thosealready reported in the literature [full symbols glass from Nimrudand Aphrodisias (◼) [2] glass from Rarsquos al-Hadd (e) and Levantinesoda ash glass (X) [12] Medieval soda ash glass from Italy (998771) [3]]Number of analysed samples is also shown

[42 43] have not shown any consistency with Greek samplesIn addition the heavily enriched 12057518O values do indicatethat their raw materials differed from those normally used inRoman andMedieval glass production and this wouldmatchthe possibility of the different origin of these materials Theuse of ash as flux may cause some 18O enrichment when theash is particularly rich in carbonate bicarbonate and hydrate[4] but hardly to this extent Previous oxygen isotopic dataobtained on Medieval soda ash glass from the Western andEastern Mediterranean (Figure 4) indicate that the additionof ash did not contribute to isotopically heavy oxygen and the12057518Ovalues essentially reflect the silica source (eg [2 3 12])In the case of Greek heavily enriched glass the silica source isdifficult to identify taking into account the fact that quartzwith anomalously heavy isotopic composition is uncommoninmagmatic sedimentary or metamorphic rocks Due to thelarge oxygen isotopic fractionation between SiO2 andwater atlow temperatures biogenic silica and chert have the highest18O16O ratios observed in rocks [44] Therefore the Greeksamples with high isotopic values may be the product oflocal glass workshops which used raw materials composedof chert with the addition of ash probably obtained fromvarious plant species other than those considered by Titeet al [4] or differently pretreated The isotopic chemicaland mineralogical data obtained on a selection of chertsamples from the quarries in Triadi of Thessaloniki (CentralMacedonia Greece) furtherly support the hypothesis of localproduction at least if we consider sample Trd 1-5 composedof only quartz

In the case of samples with moderate 18O enrichmentseveral causes must be considered to explain their valuesSample 3-3 (12057518O= 186permil) has a chemical composition quiteclose to that of Roman glass decolourised by the addition ofMn [45] sample 6-3 (12057518O= 173permil) is chemically comparableto ldquoGroup 2rdquo of Foy et al [22] and its suggested age (6thcentury AD) matches the chronological diffusion of the ref-erence group However both samples have 12057518O higher thanthe average ldquoRomanrdquo or ldquoHIMTrdquo values

In view of the high Na2O content of samples 3-3 and 6-3(Table 4) 18O enrichment may be explained by remelting ofprevious glass with addition of further amounts of natron asflux which causes an increase in Na2O concentration and inthe 18O content of the final products

Apart from their slightly higher 12057518O values (161 and164permil resp) samples 3-4 and 10-4 show quite differentchemical compositions Sample 3-4 is chemically comparablewith ldquoGroup 2rdquo [22] the chronological diffusion ofwhich alsomatches the age proposed (5th-6th centuries AD) whereassample 10-4 is similar to Roman glass 1stndash3rd centuries Adin age although the presence of Cu and Pb may also indicaterecycling of coloured and opaque glass as in the case ofsample 7-1 Both samplesmay be produced in local secondaryworkshops by recycling previous glass (perhaps from theLevantine area) with the addition of further amounts ofnatron as flux as suggested by their high Na2O content(Table 4) thus increasing the 18Ocontent of the final product

According to its chemical composition sample 13-4(Table 4 12057518O= 173permil) was obtained with soda ash as flux asdeduced from its high K2O MgO and P2O5 contents Wesuggest a different starting material for this sample as in thecase of other soda plant ash glass identified in the Greekassemblage

Lastly sample 8-4 from Thessaloniki has 12057518O of 156permilthat is within the average Roman values suggesting the use ofBelus or Volturno sand and Egyptian natron as rawmaterialsbut its chemical composition is comparable to that of glassproduced with soda plant ash as flux The chronologicaldiffusion of soda ash glass in Europe andMediterranean area[4 41] excludes a Roman age for this sample and chem-ical comparisons with 3rdndash7th-century soda ash glass fromIraq [42 43] where plant ash continued to be used as fluxthroughout the period of natron dominance in the West [4]have not shown any consistency with the present sampleTherefore great uncertainty remains in the case of sample 8-4 as regards both its age and provenance also in view of theheavily enriched oxygen signatures of other soda ash samplesidentified here (Table 4) However sample 8-4 differs fromthe others due to its lower SiO2 (616 wt) and higher Al2O3(390wt) which suggest a different silica source probably asilica sand rich in feldsparsThis source may be characterisedby a less positive oxygen signature probably related to thefeldspars content of the sand which influences the 18Ocontent of the final productThis hypothesis is also supportedby the isotopic and chemical signatures of sample 13-4Obtained again with soda plant ash as flux this sample hasAl2O3 content intermediate between that of sample 8-4 andall other Greek soda ash samples and consequently shows anintermediate 12057518O value

12 Journal of Chemistry

4 Conclusions

The results of the present study emphasize the importanceof measuring the oxygen isotopic and chemical compositionsof glass samples in order to constrain some features such asage raw materials and production technology Comparisonsof our isotopic and chemical data with those reported in theliterature particularly in the case of glass from the Levantinearea are of particular interest as regards the trading ofraw glass to secondary workshops in Greece although forsome samples obtained with soda ash as flux and heavilyenriched in 18O production from local raw materials cannotbe completely excluded

In summary the thirty-nine glass samples from northernGreece studied here have oxygen isotopic compositionswhich allow them to be subdivided into three groups

The first is composed of twenty-nine samples (severalfrom Thessaloniki and all those from Maroneia) with 12057518Ovalues equal or very close to themean value of Roman glassesfrom European and Middle Eastern areas These similaritiesimply their production with raw materials with equal or veryclose oxygen isotopic composition such as sand from therivers Belus in Palestine and Volturno in Italy as suggestedby Pliny the Elder In contrast with the remarkable isotopichomogeneity heterogeneous chemical compositions allowthe subdivision of these samples into several subgroupswhich are compared with major compositional groups iden-tified in the Western Mediterranean during the first millen-nium AD

Seven samples from Thessaloniki and all the samplesfrom Maroneia show chemical similarity with ldquoGroup 2rdquo ofFoy et al [22] while one sample shows chemical simi-larity with HIMT glass Accordingly their age should beconstrained to the late Antique period for the Thessalonikiglass and confirmed for the Maroneia samples (ie 4thndash6thcenturies AD) Nine samples from Thessaloniki are chemi-cally comparable with Roman glass although they differ incolouringdecolouring elements and recycling indicators Inparticular in some samples the identification of manganeseintentionally added as a decolourant allows us to constraintheir age according to the chronological diffusion reported inthe literature of this decolourant that is from the 3rd to 4thcenturies AD Lastly three samples from Thessaloniki(1stndash6th centuries AD) with 12057518O values comparable withldquoRomanrdquo values have chemical compositions very differentfrom ldquotypicalrdquo Roman glass suggesting different productiontechnologies

The second isotopic group is composed of four samplesfrom Thessaloniki showing heavily enriched 12057518O values(205 to 227permil) their chemical analyses indicate that theywere obtained using soda ash as flux which has little effect onthe final oxygen isotopic composition of glass These high12057518O values may be explained by the use of silica rawmaterials with heavy 18O enrichment such as chert which isalso found in the Thessaloniki region Therefore these sam-ples may be the product of local glass factories

The third group is composed of five samples from Thes-saloniki showing moderate 18O enrichment (161 to 186permil)

From the chemical point of view four samples are natronglass with compositions similar to Roman or ldquoweakrdquo HIMTgroups and one is a soda ash glass In the case of natron glassthe moderate 18O enrichment may be obtained by recyclingglass (perhaps from the Levantine area) in local secondaryworkshops with the addition of further amounts of natron asflux as suggested by their high Na2O contents In the case ofsoda ash themoderate 18O enrichment with respect to otherGreek soda ash glass may be due to the use of less positivesilica source

In conclusion these interesting results the first obtainedon glass samples from northern Greece support trades andcommercial exchanges between theNear East andGreece andsuggest although further data are required to confirm it thatthe ldquofingerprintrdquo ofGreek glass production could be related tothe use of local chert and soda ash as possible raw materials

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

The authors are grateful to D Grammenos director ofthe Archaeological Museum of Thessaloniki for providingglass samples from Thessaloniki R Carampin (Istituto diGeoscienze e Georisorse Sezione di Padova CNR) F Gallo(Dipartimento dei Beni Culturali Universita di Padova) andD Pasqual (Dipartimento diGeoscienze Universita di Padova)are thanked for their kind support to execution of chemicalanalyses Financial support was provided by ldquoEx 60rdquo fundsof the University of Padova (principal investigator AlbertaSilvestri)

References

[1] R Newton andD DavisonConservation of Glass Butterworth-Heinemann Oxford UK 1999

[2] R H Brill R N Clayton T K Mayeda and C P StapletonldquoOxygen isotope analyses of early glassesrdquo in Chemical Analysesof Early Glasses R H Brill Ed vol 2 pp 303ndash322 CorningMuseum of Glass New York NY USA 1999

[3] A Silvestri A Longinelli andGMolin ldquo12057518Omeasurements ofarchaeological glass (Roman toModern age) and rawmaterialspossible interpretationrdquo Journal of Archaeological Science vol37 no 3 pp 549ndash560 2010

[4] M S Tite A Shortland Y Maniatis D Kavoussanaki and S AHarris ldquoThe composition of the soda-rich and mixed alkaliplant ashes used in the production of glassrdquo Journal of Archae-ological Science vol 33 no 9 pp 1284ndash1292 2006

[5] C Antonaras ldquoGlass working in Roman and early ChristianThessaloniki older and more recent findsrdquo in Proceedings of theHistory Technology and Conservation of Ancient Metals Glassesand Enamels International Symposium Athens Greece Novem-ber 2011

[6] I Friedman and J R OrsquoNeil ldquoCompilation of stable isotopefractionation factors of geochemical interestrdquo in Data of

Journal of Chemistry 13

Geochemistry Geological Survey Professional Paper 440-KKchapter KK 1977

[7] A Silvestri and A Marcante ldquoThe glass of Nogara (Verona) aldquowindowrdquo on production technology of mid-Medieval times inNorthern Italyrdquo Journal of Archaeological Science vol 38 no 10pp 2509ndash2522 2011

[8] S Alberta M Gianmario and P Valentina ldquoThe stained glasswindow of the southern transept of St Anthonyrsquos Basilica(Padova Italy) study of glasses and grisaille paint layersrdquoSpectrochimica ActamdashPart B Atomic Spectroscopy vol 66 no1 pp 81ndash87 2011

[9] K Govindaraju ldquoCompilation of working values and sampledescription for 383 geostandardsrdquoGeostandards Newsletter vol18 pp 1ndash158 1994

[10] A Savitzky andM J EGolay ldquoSmoothing anddifferentiation ofdata by simplified least squares proceduresrdquo Analytical Chem-istry vol 36 no 8 pp 1627ndash1639 1964

[11] J Henderson J A Evans H J Sloane M J Leng and CDoherty ldquoThe use of oxygen strontium and lead isotopesto provenance ancient glasses in the Middle Eastrdquo Journal ofArchaeological Science vol 32 no 5 pp 665ndash673 2005

[12] K A Leslie I C Freestone D Lowry and M Thirlwall ldquoTheprovenance and technology of Near Eastern glass oxygenisotopes by laser fluorination as a complement to strontiumrdquoArchaeometry vol 48 no 2 pp 253ndash270 2006

[13] R H Brill ldquoScientific investigations of the Jalame glass andrelated findsrdquo in Excavations at Jalame Site of a Glass Factory inLate Roman Palestine G D Wienberg Ed pp 257ndash293University of Missouri Press Columbia Mo USA 1988

[14] M Pomerancblum ldquoThe distribution of heavy minerals andtheir hydraulic equivalents in sediments of the Mediterraneancontinental shelf of Israelrdquo SEPM Journal of SedimentaryResearch vol 36 pp 162ndash174 1966

[15] D J Stanley Y Mart and Y Nir ldquoClay mineral distributions tointerpret Nile cell provenance and dispersal II Coastal plainfrom Nile delta to northern Israelrdquo Journal of Coastal Researchvol 13 no 2 pp 506ndash533 1997

[16] M B Hatzopoulos and L D Loukopoulou Morrylos Centrede Recherches de lrsquoAntiquite Grecque et Romaine AthenesGreece 1989

[17] E Dotsika D Poutoukis I Tzavidopoulos Y Maniatis DIgnatiadou and B Raco ldquoA natron source at Pikrolimni Lake inGreece Geochemical evidencerdquo Journal of Geochemical Explo-ration vol 103 no 2-3 pp 133ndash143 2009

[18] H E Foster and C M Jackson ldquoThe composition of ldquonaturallycolouredrdquo late Roman vessel glass from Britain and the impli-cations for models of glass production and supplyrdquo Journal ofArchaeological Science vol 36 no 2 pp 189ndash204 2009

[19] I C Freestone ldquoAppendix chemical analysis of lsquorawrsquo glass frag-mentsrdquo in Excavations at Carthage Volume II1 The CircularHarbour North SideThe Site and FindsOther than Pottery H RHurst Ed British Academy Monographs in Archaeology N∘4p 290 Oxford University Press Oxford UK 1994

[20] I C Freestone M Ponting and M J Hughes ldquoThe origins ofByzantine glass from Maroni Petrera Cyprusrdquo Archaeometryvol 44 no 2 pp 257ndash272 2002

[21] D C W Sanderson J R Hunter and S E Warren ldquoEnergydispersive X-ray fluorescence analysis of 1stmillennium ad glassfrom Britainrdquo Journal of Archaeological Science vol 11 no 1 pp53ndash69 1984

[22] D Foy M Picon M Vichy and V Thirion-Merle ldquoCar-acterisation des verres de la fin de lrsquoAntiquite en Mediterraneeoccidentale lrsquoemergence de nouveaux courants commerciauxrdquoin Echanges et Commerce du Verre dans le Monde Antique DFoy and M D Nenna Eds Actes du Colloque de lrsquoAssociationFrancaise pour lrsquoArcheologie du Verre Aix-en-Provence etMarseille June 2001 pp 41ndash85 Monique Mergoil MontagnacFrance 2003

[23] D Rosenow and T Rehren ldquoHerding cats Roman to LateAntique glass groups from Bubastis northern Egyptrdquo Journal ofArchaeological Science vol 49 no 1 pp 170ndash184 2014

[24] P Mirti A Casoli and L Appolonia ldquoScientific analysis ofroman glass from augusta praetoriardquo Archaeometry vol 35 no2 pp 225ndash240 1993

[25] A Silvestri G Molin and G Salviulo ldquoRoman and medievalglass from the Italian area bulk characterization and relation-ships with production technologiesrdquo Archaeometry vol 47 no4 pp 797ndash816 2005

[26] A Silvestri S Tonietto and G Molin ldquoThe palaeo-Christianglass mosaic of St Prosdocimus (Padova Italy) archaeometriccharacterisation of lsquogoldrsquo tesseraerdquo Journal of ArchaeologicalScience vol 38 no 12 pp 3402ndash3414 2011

[27] F Gallo and A Silvestri ldquoMedieval glass from Rocca di Asolo(northern italy) an archaeometric studyrdquoArchaeometry vol 54no 6 pp 1023ndash1039 2012

[28] F Gallo A Marcante A Silvestri and G Molin ldquoThe glass ofthe ldquoCasa delle Bestie Feriterdquo a first systematic archaeometricstudy on Late Roman vessels from Aquileiardquo Journal of Archae-ological Science vol 41 pp 7ndash20 2014

[29] S Maltoni T Chinni M Vandini E Cirelli A Silvestri andG Molin ldquoArchaeological and archaeometric study of the glassfinds from the ancient harbour of Classe (Ravenna-Italy) newevidencerdquo Heritage Science vol 3 no 1 article 13 2015

[30] A Ceglia P Cosyns K Nys H Terryn H Thienpont and WMeulebroeck ldquoLate antique glass distribution and consumptionin Cyprus a chemical studyrdquo Journal of Archaeological Sciencevol 61 pp 213ndash222 2015

[31] N Schibille A Sterrett-Krause and I C Freestone ldquoGlassgroups glass supply and recycling in late Roman CarthagerdquoArchaeological and Anthropological Sciences pp 1ndash19 2016

[32] A Cholakova T Rehren and I C Freestone ldquoCompositionalidentification of 6th c AD glass from the Lower DanuberdquoJournal of Archaeological Science Reports vol 7 pp 625ndash6322016

[33] S Conte T Chinni R Arletti and M Vandini ldquoButrint(Albania) between eastern and western Mediterranean glassproduction EMPA and LA-ICP-MS of late antique and earlymedieval findsrdquo Journal of Archaeological Science vol 49 no1 pp 6ndash20 2014

[34] I C Freestone S Wolf and M Thirlwall ldquoThe production ofHIMT glass elemental and isotopic evidencerdquo inAnnales du 16eCongres de lrsquoAssociation Internationale pour lrsquoHistoire du Verre(AIHV rsquo05) pp 153ndash157 London UK 2005

[35] M D Nenna M Picon and M Vichy ldquoAteliers primaries etsecondaries en Egypte a lrsquoepoque greco-romainerdquo in La Routedu Verre Ateliers Primaires et Secondaires du Second Millenaireav J-C au Moyen Age M D Nenna Ed vol 33 pp 97ndash112Travaux de la Maison de lrsquoOrient Mediterraneen 2000

[36] C M Jackson ldquoMaking colourless glass in the Roman periodrdquoArchaeometry vol 47 no 4 pp 763ndash780 2005

[37] E V Sayre ldquoThe intentional use of antimony and manganese inancient glassesrdquo in Advances in Glass Technology Part 2 F R

14 Journal of Chemistry

Matson and G Rindone Eds pp 263ndash282 Plenum Press NewYork NY USA 1963

[38] H E Foster and C M Jackson ldquoThe composition of lateRomano-British colourless vessel glass glass production andconsumptionrdquo Journal of Archaeological Science vol 37 no 12pp 3068ndash3080 2010

[39] J Henderson ldquoThe raw materials of early glass productionrdquoOxford Journal of Archaeology vol 4 no 3 pp 267ndash291 1985

[40] B Gratuze and K Janssens ldquoProvenance analysis of glassartefactsrdquo inNon-Destructive Microanalysis of Cultural HeritageMaterials K Janssens and R Van Grieken Eds pp 663ndash712Elsevier Amsterdam The Netherlands 2004

[41] J Henderson ldquoTradition and experiment in first millenniumAD glass productionmdashthe emergence of early Islamic glasstechnology in late antiquityrdquoAccounts of Chemical Research vol35 no 8 pp 594ndash602 2002

[42] P Mirti M Pace M M Negro Ponzi and M Aceto ldquoICP-MSanalysis of glass fragments of Parthian and Sasanian epoch fromSeleucia and Veh Ardasır (Central Iraq)rdquoArchaeometry vol 50no 3 pp 429ndash450 2008

[43] P Mirti M Pace M Malandrino and M N Ponzi ldquoSasanianglass from Veh Ardasır new evidences by ICP-MS analysisrdquoJournal of Archaeological Science vol 36 no 4 pp 1061ndash10692009

[44] J Hoefs Stable Isotope Geochemistry Springer Berlin Ger-many 5th edition 2004

[45] A Silvestri G Molin and G Salviulo ldquoThe colourless glass ofIulia Felixrdquo Journal of Archaeological Science vol 35 no 2 pp331ndash341 2008

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 201

International Journal ofInternational Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal ofInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Journal of Chemistry 11

7 6 2 8 6

12

16

20

24훿18O

(VSM

OW

)(permil

)

Number of samples

Figure 4 Comparisons among 12057518O(VSMOW) values of plant ash glasssamples [open symbols Thessaloniki various sites (◻)] and thosealready reported in the literature [full symbols glass from Nimrudand Aphrodisias (◼) [2] glass from Rarsquos al-Hadd (e) and Levantinesoda ash glass (X) [12] Medieval soda ash glass from Italy (998771) [3]]Number of analysed samples is also shown

[42 43] have not shown any consistency with Greek samplesIn addition the heavily enriched 12057518O values do indicatethat their raw materials differed from those normally used inRoman andMedieval glass production and this wouldmatchthe possibility of the different origin of these materials Theuse of ash as flux may cause some 18O enrichment when theash is particularly rich in carbonate bicarbonate and hydrate[4] but hardly to this extent Previous oxygen isotopic dataobtained on Medieval soda ash glass from the Western andEastern Mediterranean (Figure 4) indicate that the additionof ash did not contribute to isotopically heavy oxygen and the12057518Ovalues essentially reflect the silica source (eg [2 3 12])In the case of Greek heavily enriched glass the silica source isdifficult to identify taking into account the fact that quartzwith anomalously heavy isotopic composition is uncommoninmagmatic sedimentary or metamorphic rocks Due to thelarge oxygen isotopic fractionation between SiO2 andwater atlow temperatures biogenic silica and chert have the highest18O16O ratios observed in rocks [44] Therefore the Greeksamples with high isotopic values may be the product oflocal glass workshops which used raw materials composedof chert with the addition of ash probably obtained fromvarious plant species other than those considered by Titeet al [4] or differently pretreated The isotopic chemicaland mineralogical data obtained on a selection of chertsamples from the quarries in Triadi of Thessaloniki (CentralMacedonia Greece) furtherly support the hypothesis of localproduction at least if we consider sample Trd 1-5 composedof only quartz

In the case of samples with moderate 18O enrichmentseveral causes must be considered to explain their valuesSample 3-3 (12057518O= 186permil) has a chemical composition quiteclose to that of Roman glass decolourised by the addition ofMn [45] sample 6-3 (12057518O= 173permil) is chemically comparableto ldquoGroup 2rdquo of Foy et al [22] and its suggested age (6thcentury AD) matches the chronological diffusion of the ref-erence group However both samples have 12057518O higher thanthe average ldquoRomanrdquo or ldquoHIMTrdquo values

In view of the high Na2O content of samples 3-3 and 6-3(Table 4) 18O enrichment may be explained by remelting ofprevious glass with addition of further amounts of natron asflux which causes an increase in Na2O concentration and inthe 18O content of the final products

Apart from their slightly higher 12057518O values (161 and164permil resp) samples 3-4 and 10-4 show quite differentchemical compositions Sample 3-4 is chemically comparablewith ldquoGroup 2rdquo [22] the chronological diffusion ofwhich alsomatches the age proposed (5th-6th centuries AD) whereassample 10-4 is similar to Roman glass 1stndash3rd centuries Adin age although the presence of Cu and Pb may also indicaterecycling of coloured and opaque glass as in the case ofsample 7-1 Both samplesmay be produced in local secondaryworkshops by recycling previous glass (perhaps from theLevantine area) with the addition of further amounts ofnatron as flux as suggested by their high Na2O content(Table 4) thus increasing the 18Ocontent of the final product

According to its chemical composition sample 13-4(Table 4 12057518O= 173permil) was obtained with soda ash as flux asdeduced from its high K2O MgO and P2O5 contents Wesuggest a different starting material for this sample as in thecase of other soda plant ash glass identified in the Greekassemblage

Lastly sample 8-4 from Thessaloniki has 12057518O of 156permilthat is within the average Roman values suggesting the use ofBelus or Volturno sand and Egyptian natron as rawmaterialsbut its chemical composition is comparable to that of glassproduced with soda plant ash as flux The chronologicaldiffusion of soda ash glass in Europe andMediterranean area[4 41] excludes a Roman age for this sample and chem-ical comparisons with 3rdndash7th-century soda ash glass fromIraq [42 43] where plant ash continued to be used as fluxthroughout the period of natron dominance in the West [4]have not shown any consistency with the present sampleTherefore great uncertainty remains in the case of sample 8-4 as regards both its age and provenance also in view of theheavily enriched oxygen signatures of other soda ash samplesidentified here (Table 4) However sample 8-4 differs fromthe others due to its lower SiO2 (616 wt) and higher Al2O3(390wt) which suggest a different silica source probably asilica sand rich in feldsparsThis source may be characterisedby a less positive oxygen signature probably related to thefeldspars content of the sand which influences the 18Ocontent of the final productThis hypothesis is also supportedby the isotopic and chemical signatures of sample 13-4Obtained again with soda plant ash as flux this sample hasAl2O3 content intermediate between that of sample 8-4 andall other Greek soda ash samples and consequently shows anintermediate 12057518O value

12 Journal of Chemistry

4 Conclusions

The results of the present study emphasize the importanceof measuring the oxygen isotopic and chemical compositionsof glass samples in order to constrain some features such asage raw materials and production technology Comparisonsof our isotopic and chemical data with those reported in theliterature particularly in the case of glass from the Levantinearea are of particular interest as regards the trading ofraw glass to secondary workshops in Greece although forsome samples obtained with soda ash as flux and heavilyenriched in 18O production from local raw materials cannotbe completely excluded

In summary the thirty-nine glass samples from northernGreece studied here have oxygen isotopic compositionswhich allow them to be subdivided into three groups

The first is composed of twenty-nine samples (severalfrom Thessaloniki and all those from Maroneia) with 12057518Ovalues equal or very close to themean value of Roman glassesfrom European and Middle Eastern areas These similaritiesimply their production with raw materials with equal or veryclose oxygen isotopic composition such as sand from therivers Belus in Palestine and Volturno in Italy as suggestedby Pliny the Elder In contrast with the remarkable isotopichomogeneity heterogeneous chemical compositions allowthe subdivision of these samples into several subgroupswhich are compared with major compositional groups iden-tified in the Western Mediterranean during the first millen-nium AD

Seven samples from Thessaloniki and all the samplesfrom Maroneia show chemical similarity with ldquoGroup 2rdquo ofFoy et al [22] while one sample shows chemical simi-larity with HIMT glass Accordingly their age should beconstrained to the late Antique period for the Thessalonikiglass and confirmed for the Maroneia samples (ie 4thndash6thcenturies AD) Nine samples from Thessaloniki are chemi-cally comparable with Roman glass although they differ incolouringdecolouring elements and recycling indicators Inparticular in some samples the identification of manganeseintentionally added as a decolourant allows us to constraintheir age according to the chronological diffusion reported inthe literature of this decolourant that is from the 3rd to 4thcenturies AD Lastly three samples from Thessaloniki(1stndash6th centuries AD) with 12057518O values comparable withldquoRomanrdquo values have chemical compositions very differentfrom ldquotypicalrdquo Roman glass suggesting different productiontechnologies

The second isotopic group is composed of four samplesfrom Thessaloniki showing heavily enriched 12057518O values(205 to 227permil) their chemical analyses indicate that theywere obtained using soda ash as flux which has little effect onthe final oxygen isotopic composition of glass These high12057518O values may be explained by the use of silica rawmaterials with heavy 18O enrichment such as chert which isalso found in the Thessaloniki region Therefore these sam-ples may be the product of local glass factories

The third group is composed of five samples from Thes-saloniki showing moderate 18O enrichment (161 to 186permil)

From the chemical point of view four samples are natronglass with compositions similar to Roman or ldquoweakrdquo HIMTgroups and one is a soda ash glass In the case of natron glassthe moderate 18O enrichment may be obtained by recyclingglass (perhaps from the Levantine area) in local secondaryworkshops with the addition of further amounts of natron asflux as suggested by their high Na2O contents In the case ofsoda ash themoderate 18O enrichment with respect to otherGreek soda ash glass may be due to the use of less positivesilica source

In conclusion these interesting results the first obtainedon glass samples from northern Greece support trades andcommercial exchanges between theNear East andGreece andsuggest although further data are required to confirm it thatthe ldquofingerprintrdquo ofGreek glass production could be related tothe use of local chert and soda ash as possible raw materials

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

The authors are grateful to D Grammenos director ofthe Archaeological Museum of Thessaloniki for providingglass samples from Thessaloniki R Carampin (Istituto diGeoscienze e Georisorse Sezione di Padova CNR) F Gallo(Dipartimento dei Beni Culturali Universita di Padova) andD Pasqual (Dipartimento diGeoscienze Universita di Padova)are thanked for their kind support to execution of chemicalanalyses Financial support was provided by ldquoEx 60rdquo fundsof the University of Padova (principal investigator AlbertaSilvestri)

References

[1] R Newton andD DavisonConservation of Glass Butterworth-Heinemann Oxford UK 1999

[2] R H Brill R N Clayton T K Mayeda and C P StapletonldquoOxygen isotope analyses of early glassesrdquo in Chemical Analysesof Early Glasses R H Brill Ed vol 2 pp 303ndash322 CorningMuseum of Glass New York NY USA 1999

[3] A Silvestri A Longinelli andGMolin ldquo12057518Omeasurements ofarchaeological glass (Roman toModern age) and rawmaterialspossible interpretationrdquo Journal of Archaeological Science vol37 no 3 pp 549ndash560 2010

[4] M S Tite A Shortland Y Maniatis D Kavoussanaki and S AHarris ldquoThe composition of the soda-rich and mixed alkaliplant ashes used in the production of glassrdquo Journal of Archae-ological Science vol 33 no 9 pp 1284ndash1292 2006

[5] C Antonaras ldquoGlass working in Roman and early ChristianThessaloniki older and more recent findsrdquo in Proceedings of theHistory Technology and Conservation of Ancient Metals Glassesand Enamels International Symposium Athens Greece Novem-ber 2011

[6] I Friedman and J R OrsquoNeil ldquoCompilation of stable isotopefractionation factors of geochemical interestrdquo in Data of

Journal of Chemistry 13

Geochemistry Geological Survey Professional Paper 440-KKchapter KK 1977

[7] A Silvestri and A Marcante ldquoThe glass of Nogara (Verona) aldquowindowrdquo on production technology of mid-Medieval times inNorthern Italyrdquo Journal of Archaeological Science vol 38 no 10pp 2509ndash2522 2011

[8] S Alberta M Gianmario and P Valentina ldquoThe stained glasswindow of the southern transept of St Anthonyrsquos Basilica(Padova Italy) study of glasses and grisaille paint layersrdquoSpectrochimica ActamdashPart B Atomic Spectroscopy vol 66 no1 pp 81ndash87 2011

[9] K Govindaraju ldquoCompilation of working values and sampledescription for 383 geostandardsrdquoGeostandards Newsletter vol18 pp 1ndash158 1994

[10] A Savitzky andM J EGolay ldquoSmoothing anddifferentiation ofdata by simplified least squares proceduresrdquo Analytical Chem-istry vol 36 no 8 pp 1627ndash1639 1964

[11] J Henderson J A Evans H J Sloane M J Leng and CDoherty ldquoThe use of oxygen strontium and lead isotopesto provenance ancient glasses in the Middle Eastrdquo Journal ofArchaeological Science vol 32 no 5 pp 665ndash673 2005

[12] K A Leslie I C Freestone D Lowry and M Thirlwall ldquoTheprovenance and technology of Near Eastern glass oxygenisotopes by laser fluorination as a complement to strontiumrdquoArchaeometry vol 48 no 2 pp 253ndash270 2006

[13] R H Brill ldquoScientific investigations of the Jalame glass andrelated findsrdquo in Excavations at Jalame Site of a Glass Factory inLate Roman Palestine G D Wienberg Ed pp 257ndash293University of Missouri Press Columbia Mo USA 1988

[14] M Pomerancblum ldquoThe distribution of heavy minerals andtheir hydraulic equivalents in sediments of the Mediterraneancontinental shelf of Israelrdquo SEPM Journal of SedimentaryResearch vol 36 pp 162ndash174 1966

[15] D J Stanley Y Mart and Y Nir ldquoClay mineral distributions tointerpret Nile cell provenance and dispersal II Coastal plainfrom Nile delta to northern Israelrdquo Journal of Coastal Researchvol 13 no 2 pp 506ndash533 1997

[16] M B Hatzopoulos and L D Loukopoulou Morrylos Centrede Recherches de lrsquoAntiquite Grecque et Romaine AthenesGreece 1989

[17] E Dotsika D Poutoukis I Tzavidopoulos Y Maniatis DIgnatiadou and B Raco ldquoA natron source at Pikrolimni Lake inGreece Geochemical evidencerdquo Journal of Geochemical Explo-ration vol 103 no 2-3 pp 133ndash143 2009

[18] H E Foster and C M Jackson ldquoThe composition of ldquonaturallycolouredrdquo late Roman vessel glass from Britain and the impli-cations for models of glass production and supplyrdquo Journal ofArchaeological Science vol 36 no 2 pp 189ndash204 2009

[19] I C Freestone ldquoAppendix chemical analysis of lsquorawrsquo glass frag-mentsrdquo in Excavations at Carthage Volume II1 The CircularHarbour North SideThe Site and FindsOther than Pottery H RHurst Ed British Academy Monographs in Archaeology N∘4p 290 Oxford University Press Oxford UK 1994

[20] I C Freestone M Ponting and M J Hughes ldquoThe origins ofByzantine glass from Maroni Petrera Cyprusrdquo Archaeometryvol 44 no 2 pp 257ndash272 2002

[21] D C W Sanderson J R Hunter and S E Warren ldquoEnergydispersive X-ray fluorescence analysis of 1stmillennium ad glassfrom Britainrdquo Journal of Archaeological Science vol 11 no 1 pp53ndash69 1984

[22] D Foy M Picon M Vichy and V Thirion-Merle ldquoCar-acterisation des verres de la fin de lrsquoAntiquite en Mediterraneeoccidentale lrsquoemergence de nouveaux courants commerciauxrdquoin Echanges et Commerce du Verre dans le Monde Antique DFoy and M D Nenna Eds Actes du Colloque de lrsquoAssociationFrancaise pour lrsquoArcheologie du Verre Aix-en-Provence etMarseille June 2001 pp 41ndash85 Monique Mergoil MontagnacFrance 2003

[23] D Rosenow and T Rehren ldquoHerding cats Roman to LateAntique glass groups from Bubastis northern Egyptrdquo Journal ofArchaeological Science vol 49 no 1 pp 170ndash184 2014

[24] P Mirti A Casoli and L Appolonia ldquoScientific analysis ofroman glass from augusta praetoriardquo Archaeometry vol 35 no2 pp 225ndash240 1993

[25] A Silvestri G Molin and G Salviulo ldquoRoman and medievalglass from the Italian area bulk characterization and relation-ships with production technologiesrdquo Archaeometry vol 47 no4 pp 797ndash816 2005

[26] A Silvestri S Tonietto and G Molin ldquoThe palaeo-Christianglass mosaic of St Prosdocimus (Padova Italy) archaeometriccharacterisation of lsquogoldrsquo tesseraerdquo Journal of ArchaeologicalScience vol 38 no 12 pp 3402ndash3414 2011

[27] F Gallo and A Silvestri ldquoMedieval glass from Rocca di Asolo(northern italy) an archaeometric studyrdquoArchaeometry vol 54no 6 pp 1023ndash1039 2012

[28] F Gallo A Marcante A Silvestri and G Molin ldquoThe glass ofthe ldquoCasa delle Bestie Feriterdquo a first systematic archaeometricstudy on Late Roman vessels from Aquileiardquo Journal of Archae-ological Science vol 41 pp 7ndash20 2014

[29] S Maltoni T Chinni M Vandini E Cirelli A Silvestri andG Molin ldquoArchaeological and archaeometric study of the glassfinds from the ancient harbour of Classe (Ravenna-Italy) newevidencerdquo Heritage Science vol 3 no 1 article 13 2015

[30] A Ceglia P Cosyns K Nys H Terryn H Thienpont and WMeulebroeck ldquoLate antique glass distribution and consumptionin Cyprus a chemical studyrdquo Journal of Archaeological Sciencevol 61 pp 213ndash222 2015

[31] N Schibille A Sterrett-Krause and I C Freestone ldquoGlassgroups glass supply and recycling in late Roman CarthagerdquoArchaeological and Anthropological Sciences pp 1ndash19 2016

[32] A Cholakova T Rehren and I C Freestone ldquoCompositionalidentification of 6th c AD glass from the Lower DanuberdquoJournal of Archaeological Science Reports vol 7 pp 625ndash6322016

[33] S Conte T Chinni R Arletti and M Vandini ldquoButrint(Albania) between eastern and western Mediterranean glassproduction EMPA and LA-ICP-MS of late antique and earlymedieval findsrdquo Journal of Archaeological Science vol 49 no1 pp 6ndash20 2014

[34] I C Freestone S Wolf and M Thirlwall ldquoThe production ofHIMT glass elemental and isotopic evidencerdquo inAnnales du 16eCongres de lrsquoAssociation Internationale pour lrsquoHistoire du Verre(AIHV rsquo05) pp 153ndash157 London UK 2005

[35] M D Nenna M Picon and M Vichy ldquoAteliers primaries etsecondaries en Egypte a lrsquoepoque greco-romainerdquo in La Routedu Verre Ateliers Primaires et Secondaires du Second Millenaireav J-C au Moyen Age M D Nenna Ed vol 33 pp 97ndash112Travaux de la Maison de lrsquoOrient Mediterraneen 2000

[36] C M Jackson ldquoMaking colourless glass in the Roman periodrdquoArchaeometry vol 47 no 4 pp 763ndash780 2005

[37] E V Sayre ldquoThe intentional use of antimony and manganese inancient glassesrdquo in Advances in Glass Technology Part 2 F R

14 Journal of Chemistry

Matson and G Rindone Eds pp 263ndash282 Plenum Press NewYork NY USA 1963

[38] H E Foster and C M Jackson ldquoThe composition of lateRomano-British colourless vessel glass glass production andconsumptionrdquo Journal of Archaeological Science vol 37 no 12pp 3068ndash3080 2010

[39] J Henderson ldquoThe raw materials of early glass productionrdquoOxford Journal of Archaeology vol 4 no 3 pp 267ndash291 1985

[40] B Gratuze and K Janssens ldquoProvenance analysis of glassartefactsrdquo inNon-Destructive Microanalysis of Cultural HeritageMaterials K Janssens and R Van Grieken Eds pp 663ndash712Elsevier Amsterdam The Netherlands 2004

[41] J Henderson ldquoTradition and experiment in first millenniumAD glass productionmdashthe emergence of early Islamic glasstechnology in late antiquityrdquoAccounts of Chemical Research vol35 no 8 pp 594ndash602 2002

[42] P Mirti M Pace M M Negro Ponzi and M Aceto ldquoICP-MSanalysis of glass fragments of Parthian and Sasanian epoch fromSeleucia and Veh Ardasır (Central Iraq)rdquoArchaeometry vol 50no 3 pp 429ndash450 2008

[43] P Mirti M Pace M Malandrino and M N Ponzi ldquoSasanianglass from Veh Ardasır new evidences by ICP-MS analysisrdquoJournal of Archaeological Science vol 36 no 4 pp 1061ndash10692009

[44] J Hoefs Stable Isotope Geochemistry Springer Berlin Ger-many 5th edition 2004

[45] A Silvestri G Molin and G Salviulo ldquoThe colourless glass ofIulia Felixrdquo Journal of Archaeological Science vol 35 no 2 pp331ndash341 2008

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 201

International Journal ofInternational Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal ofInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

12 Journal of Chemistry

4 Conclusions

The results of the present study emphasize the importanceof measuring the oxygen isotopic and chemical compositionsof glass samples in order to constrain some features such asage raw materials and production technology Comparisonsof our isotopic and chemical data with those reported in theliterature particularly in the case of glass from the Levantinearea are of particular interest as regards the trading ofraw glass to secondary workshops in Greece although forsome samples obtained with soda ash as flux and heavilyenriched in 18O production from local raw materials cannotbe completely excluded

In summary the thirty-nine glass samples from northernGreece studied here have oxygen isotopic compositionswhich allow them to be subdivided into three groups

The first is composed of twenty-nine samples (severalfrom Thessaloniki and all those from Maroneia) with 12057518Ovalues equal or very close to themean value of Roman glassesfrom European and Middle Eastern areas These similaritiesimply their production with raw materials with equal or veryclose oxygen isotopic composition such as sand from therivers Belus in Palestine and Volturno in Italy as suggestedby Pliny the Elder In contrast with the remarkable isotopichomogeneity heterogeneous chemical compositions allowthe subdivision of these samples into several subgroupswhich are compared with major compositional groups iden-tified in the Western Mediterranean during the first millen-nium AD

Seven samples from Thessaloniki and all the samplesfrom Maroneia show chemical similarity with ldquoGroup 2rdquo ofFoy et al [22] while one sample shows chemical simi-larity with HIMT glass Accordingly their age should beconstrained to the late Antique period for the Thessalonikiglass and confirmed for the Maroneia samples (ie 4thndash6thcenturies AD) Nine samples from Thessaloniki are chemi-cally comparable with Roman glass although they differ incolouringdecolouring elements and recycling indicators Inparticular in some samples the identification of manganeseintentionally added as a decolourant allows us to constraintheir age according to the chronological diffusion reported inthe literature of this decolourant that is from the 3rd to 4thcenturies AD Lastly three samples from Thessaloniki(1stndash6th centuries AD) with 12057518O values comparable withldquoRomanrdquo values have chemical compositions very differentfrom ldquotypicalrdquo Roman glass suggesting different productiontechnologies

The second isotopic group is composed of four samplesfrom Thessaloniki showing heavily enriched 12057518O values(205 to 227permil) their chemical analyses indicate that theywere obtained using soda ash as flux which has little effect onthe final oxygen isotopic composition of glass These high12057518O values may be explained by the use of silica rawmaterials with heavy 18O enrichment such as chert which isalso found in the Thessaloniki region Therefore these sam-ples may be the product of local glass factories

The third group is composed of five samples from Thes-saloniki showing moderate 18O enrichment (161 to 186permil)

From the chemical point of view four samples are natronglass with compositions similar to Roman or ldquoweakrdquo HIMTgroups and one is a soda ash glass In the case of natron glassthe moderate 18O enrichment may be obtained by recyclingglass (perhaps from the Levantine area) in local secondaryworkshops with the addition of further amounts of natron asflux as suggested by their high Na2O contents In the case ofsoda ash themoderate 18O enrichment with respect to otherGreek soda ash glass may be due to the use of less positivesilica source

In conclusion these interesting results the first obtainedon glass samples from northern Greece support trades andcommercial exchanges between theNear East andGreece andsuggest although further data are required to confirm it thatthe ldquofingerprintrdquo ofGreek glass production could be related tothe use of local chert and soda ash as possible raw materials

Conflicts of Interest

The authors declare that there are no conflicts of interestregarding the publication of this paper

Acknowledgments

The authors are grateful to D Grammenos director ofthe Archaeological Museum of Thessaloniki for providingglass samples from Thessaloniki R Carampin (Istituto diGeoscienze e Georisorse Sezione di Padova CNR) F Gallo(Dipartimento dei Beni Culturali Universita di Padova) andD Pasqual (Dipartimento diGeoscienze Universita di Padova)are thanked for their kind support to execution of chemicalanalyses Financial support was provided by ldquoEx 60rdquo fundsof the University of Padova (principal investigator AlbertaSilvestri)

References

[1] R Newton andD DavisonConservation of Glass Butterworth-Heinemann Oxford UK 1999

[2] R H Brill R N Clayton T K Mayeda and C P StapletonldquoOxygen isotope analyses of early glassesrdquo in Chemical Analysesof Early Glasses R H Brill Ed vol 2 pp 303ndash322 CorningMuseum of Glass New York NY USA 1999

[3] A Silvestri A Longinelli andGMolin ldquo12057518Omeasurements ofarchaeological glass (Roman toModern age) and rawmaterialspossible interpretationrdquo Journal of Archaeological Science vol37 no 3 pp 549ndash560 2010

[4] M S Tite A Shortland Y Maniatis D Kavoussanaki and S AHarris ldquoThe composition of the soda-rich and mixed alkaliplant ashes used in the production of glassrdquo Journal of Archae-ological Science vol 33 no 9 pp 1284ndash1292 2006

[5] C Antonaras ldquoGlass working in Roman and early ChristianThessaloniki older and more recent findsrdquo in Proceedings of theHistory Technology and Conservation of Ancient Metals Glassesand Enamels International Symposium Athens Greece Novem-ber 2011

[6] I Friedman and J R OrsquoNeil ldquoCompilation of stable isotopefractionation factors of geochemical interestrdquo in Data of

Journal of Chemistry 13

Geochemistry Geological Survey Professional Paper 440-KKchapter KK 1977

[7] A Silvestri and A Marcante ldquoThe glass of Nogara (Verona) aldquowindowrdquo on production technology of mid-Medieval times inNorthern Italyrdquo Journal of Archaeological Science vol 38 no 10pp 2509ndash2522 2011

[8] S Alberta M Gianmario and P Valentina ldquoThe stained glasswindow of the southern transept of St Anthonyrsquos Basilica(Padova Italy) study of glasses and grisaille paint layersrdquoSpectrochimica ActamdashPart B Atomic Spectroscopy vol 66 no1 pp 81ndash87 2011

[9] K Govindaraju ldquoCompilation of working values and sampledescription for 383 geostandardsrdquoGeostandards Newsletter vol18 pp 1ndash158 1994

[10] A Savitzky andM J EGolay ldquoSmoothing anddifferentiation ofdata by simplified least squares proceduresrdquo Analytical Chem-istry vol 36 no 8 pp 1627ndash1639 1964

[11] J Henderson J A Evans H J Sloane M J Leng and CDoherty ldquoThe use of oxygen strontium and lead isotopesto provenance ancient glasses in the Middle Eastrdquo Journal ofArchaeological Science vol 32 no 5 pp 665ndash673 2005

[12] K A Leslie I C Freestone D Lowry and M Thirlwall ldquoTheprovenance and technology of Near Eastern glass oxygenisotopes by laser fluorination as a complement to strontiumrdquoArchaeometry vol 48 no 2 pp 253ndash270 2006

[13] R H Brill ldquoScientific investigations of the Jalame glass andrelated findsrdquo in Excavations at Jalame Site of a Glass Factory inLate Roman Palestine G D Wienberg Ed pp 257ndash293University of Missouri Press Columbia Mo USA 1988

[14] M Pomerancblum ldquoThe distribution of heavy minerals andtheir hydraulic equivalents in sediments of the Mediterraneancontinental shelf of Israelrdquo SEPM Journal of SedimentaryResearch vol 36 pp 162ndash174 1966

[15] D J Stanley Y Mart and Y Nir ldquoClay mineral distributions tointerpret Nile cell provenance and dispersal II Coastal plainfrom Nile delta to northern Israelrdquo Journal of Coastal Researchvol 13 no 2 pp 506ndash533 1997

[16] M B Hatzopoulos and L D Loukopoulou Morrylos Centrede Recherches de lrsquoAntiquite Grecque et Romaine AthenesGreece 1989

[17] E Dotsika D Poutoukis I Tzavidopoulos Y Maniatis DIgnatiadou and B Raco ldquoA natron source at Pikrolimni Lake inGreece Geochemical evidencerdquo Journal of Geochemical Explo-ration vol 103 no 2-3 pp 133ndash143 2009

[18] H E Foster and C M Jackson ldquoThe composition of ldquonaturallycolouredrdquo late Roman vessel glass from Britain and the impli-cations for models of glass production and supplyrdquo Journal ofArchaeological Science vol 36 no 2 pp 189ndash204 2009

[19] I C Freestone ldquoAppendix chemical analysis of lsquorawrsquo glass frag-mentsrdquo in Excavations at Carthage Volume II1 The CircularHarbour North SideThe Site and FindsOther than Pottery H RHurst Ed British Academy Monographs in Archaeology N∘4p 290 Oxford University Press Oxford UK 1994

[20] I C Freestone M Ponting and M J Hughes ldquoThe origins ofByzantine glass from Maroni Petrera Cyprusrdquo Archaeometryvol 44 no 2 pp 257ndash272 2002

[21] D C W Sanderson J R Hunter and S E Warren ldquoEnergydispersive X-ray fluorescence analysis of 1stmillennium ad glassfrom Britainrdquo Journal of Archaeological Science vol 11 no 1 pp53ndash69 1984

[22] D Foy M Picon M Vichy and V Thirion-Merle ldquoCar-acterisation des verres de la fin de lrsquoAntiquite en Mediterraneeoccidentale lrsquoemergence de nouveaux courants commerciauxrdquoin Echanges et Commerce du Verre dans le Monde Antique DFoy and M D Nenna Eds Actes du Colloque de lrsquoAssociationFrancaise pour lrsquoArcheologie du Verre Aix-en-Provence etMarseille June 2001 pp 41ndash85 Monique Mergoil MontagnacFrance 2003

[23] D Rosenow and T Rehren ldquoHerding cats Roman to LateAntique glass groups from Bubastis northern Egyptrdquo Journal ofArchaeological Science vol 49 no 1 pp 170ndash184 2014

[24] P Mirti A Casoli and L Appolonia ldquoScientific analysis ofroman glass from augusta praetoriardquo Archaeometry vol 35 no2 pp 225ndash240 1993

[25] A Silvestri G Molin and G Salviulo ldquoRoman and medievalglass from the Italian area bulk characterization and relation-ships with production technologiesrdquo Archaeometry vol 47 no4 pp 797ndash816 2005

[26] A Silvestri S Tonietto and G Molin ldquoThe palaeo-Christianglass mosaic of St Prosdocimus (Padova Italy) archaeometriccharacterisation of lsquogoldrsquo tesseraerdquo Journal of ArchaeologicalScience vol 38 no 12 pp 3402ndash3414 2011

[27] F Gallo and A Silvestri ldquoMedieval glass from Rocca di Asolo(northern italy) an archaeometric studyrdquoArchaeometry vol 54no 6 pp 1023ndash1039 2012

[28] F Gallo A Marcante A Silvestri and G Molin ldquoThe glass ofthe ldquoCasa delle Bestie Feriterdquo a first systematic archaeometricstudy on Late Roman vessels from Aquileiardquo Journal of Archae-ological Science vol 41 pp 7ndash20 2014

[29] S Maltoni T Chinni M Vandini E Cirelli A Silvestri andG Molin ldquoArchaeological and archaeometric study of the glassfinds from the ancient harbour of Classe (Ravenna-Italy) newevidencerdquo Heritage Science vol 3 no 1 article 13 2015

[30] A Ceglia P Cosyns K Nys H Terryn H Thienpont and WMeulebroeck ldquoLate antique glass distribution and consumptionin Cyprus a chemical studyrdquo Journal of Archaeological Sciencevol 61 pp 213ndash222 2015

[31] N Schibille A Sterrett-Krause and I C Freestone ldquoGlassgroups glass supply and recycling in late Roman CarthagerdquoArchaeological and Anthropological Sciences pp 1ndash19 2016

[32] A Cholakova T Rehren and I C Freestone ldquoCompositionalidentification of 6th c AD glass from the Lower DanuberdquoJournal of Archaeological Science Reports vol 7 pp 625ndash6322016

[33] S Conte T Chinni R Arletti and M Vandini ldquoButrint(Albania) between eastern and western Mediterranean glassproduction EMPA and LA-ICP-MS of late antique and earlymedieval findsrdquo Journal of Archaeological Science vol 49 no1 pp 6ndash20 2014

[34] I C Freestone S Wolf and M Thirlwall ldquoThe production ofHIMT glass elemental and isotopic evidencerdquo inAnnales du 16eCongres de lrsquoAssociation Internationale pour lrsquoHistoire du Verre(AIHV rsquo05) pp 153ndash157 London UK 2005

[35] M D Nenna M Picon and M Vichy ldquoAteliers primaries etsecondaries en Egypte a lrsquoepoque greco-romainerdquo in La Routedu Verre Ateliers Primaires et Secondaires du Second Millenaireav J-C au Moyen Age M D Nenna Ed vol 33 pp 97ndash112Travaux de la Maison de lrsquoOrient Mediterraneen 2000

[36] C M Jackson ldquoMaking colourless glass in the Roman periodrdquoArchaeometry vol 47 no 4 pp 763ndash780 2005

[37] E V Sayre ldquoThe intentional use of antimony and manganese inancient glassesrdquo in Advances in Glass Technology Part 2 F R

14 Journal of Chemistry

Matson and G Rindone Eds pp 263ndash282 Plenum Press NewYork NY USA 1963

[38] H E Foster and C M Jackson ldquoThe composition of lateRomano-British colourless vessel glass glass production andconsumptionrdquo Journal of Archaeological Science vol 37 no 12pp 3068ndash3080 2010

[39] J Henderson ldquoThe raw materials of early glass productionrdquoOxford Journal of Archaeology vol 4 no 3 pp 267ndash291 1985

[40] B Gratuze and K Janssens ldquoProvenance analysis of glassartefactsrdquo inNon-Destructive Microanalysis of Cultural HeritageMaterials K Janssens and R Van Grieken Eds pp 663ndash712Elsevier Amsterdam The Netherlands 2004

[41] J Henderson ldquoTradition and experiment in first millenniumAD glass productionmdashthe emergence of early Islamic glasstechnology in late antiquityrdquoAccounts of Chemical Research vol35 no 8 pp 594ndash602 2002

[42] P Mirti M Pace M M Negro Ponzi and M Aceto ldquoICP-MSanalysis of glass fragments of Parthian and Sasanian epoch fromSeleucia and Veh Ardasır (Central Iraq)rdquoArchaeometry vol 50no 3 pp 429ndash450 2008

[43] P Mirti M Pace M Malandrino and M N Ponzi ldquoSasanianglass from Veh Ardasır new evidences by ICP-MS analysisrdquoJournal of Archaeological Science vol 36 no 4 pp 1061ndash10692009

[44] J Hoefs Stable Isotope Geochemistry Springer Berlin Ger-many 5th edition 2004

[45] A Silvestri G Molin and G Salviulo ldquoThe colourless glass ofIulia Felixrdquo Journal of Archaeological Science vol 35 no 2 pp331ndash341 2008

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 201

International Journal ofInternational Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal ofInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Journal of Chemistry 13

Geochemistry Geological Survey Professional Paper 440-KKchapter KK 1977

[7] A Silvestri and A Marcante ldquoThe glass of Nogara (Verona) aldquowindowrdquo on production technology of mid-Medieval times inNorthern Italyrdquo Journal of Archaeological Science vol 38 no 10pp 2509ndash2522 2011

[8] S Alberta M Gianmario and P Valentina ldquoThe stained glasswindow of the southern transept of St Anthonyrsquos Basilica(Padova Italy) study of glasses and grisaille paint layersrdquoSpectrochimica ActamdashPart B Atomic Spectroscopy vol 66 no1 pp 81ndash87 2011

[9] K Govindaraju ldquoCompilation of working values and sampledescription for 383 geostandardsrdquoGeostandards Newsletter vol18 pp 1ndash158 1994

[10] A Savitzky andM J EGolay ldquoSmoothing anddifferentiation ofdata by simplified least squares proceduresrdquo Analytical Chem-istry vol 36 no 8 pp 1627ndash1639 1964

[11] J Henderson J A Evans H J Sloane M J Leng and CDoherty ldquoThe use of oxygen strontium and lead isotopesto provenance ancient glasses in the Middle Eastrdquo Journal ofArchaeological Science vol 32 no 5 pp 665ndash673 2005

[12] K A Leslie I C Freestone D Lowry and M Thirlwall ldquoTheprovenance and technology of Near Eastern glass oxygenisotopes by laser fluorination as a complement to strontiumrdquoArchaeometry vol 48 no 2 pp 253ndash270 2006

[13] R H Brill ldquoScientific investigations of the Jalame glass andrelated findsrdquo in Excavations at Jalame Site of a Glass Factory inLate Roman Palestine G D Wienberg Ed pp 257ndash293University of Missouri Press Columbia Mo USA 1988

[14] M Pomerancblum ldquoThe distribution of heavy minerals andtheir hydraulic equivalents in sediments of the Mediterraneancontinental shelf of Israelrdquo SEPM Journal of SedimentaryResearch vol 36 pp 162ndash174 1966

[15] D J Stanley Y Mart and Y Nir ldquoClay mineral distributions tointerpret Nile cell provenance and dispersal II Coastal plainfrom Nile delta to northern Israelrdquo Journal of Coastal Researchvol 13 no 2 pp 506ndash533 1997

[16] M B Hatzopoulos and L D Loukopoulou Morrylos Centrede Recherches de lrsquoAntiquite Grecque et Romaine AthenesGreece 1989

[17] E Dotsika D Poutoukis I Tzavidopoulos Y Maniatis DIgnatiadou and B Raco ldquoA natron source at Pikrolimni Lake inGreece Geochemical evidencerdquo Journal of Geochemical Explo-ration vol 103 no 2-3 pp 133ndash143 2009

[18] H E Foster and C M Jackson ldquoThe composition of ldquonaturallycolouredrdquo late Roman vessel glass from Britain and the impli-cations for models of glass production and supplyrdquo Journal ofArchaeological Science vol 36 no 2 pp 189ndash204 2009

[19] I C Freestone ldquoAppendix chemical analysis of lsquorawrsquo glass frag-mentsrdquo in Excavations at Carthage Volume II1 The CircularHarbour North SideThe Site and FindsOther than Pottery H RHurst Ed British Academy Monographs in Archaeology N∘4p 290 Oxford University Press Oxford UK 1994

[20] I C Freestone M Ponting and M J Hughes ldquoThe origins ofByzantine glass from Maroni Petrera Cyprusrdquo Archaeometryvol 44 no 2 pp 257ndash272 2002

[21] D C W Sanderson J R Hunter and S E Warren ldquoEnergydispersive X-ray fluorescence analysis of 1stmillennium ad glassfrom Britainrdquo Journal of Archaeological Science vol 11 no 1 pp53ndash69 1984

[22] D Foy M Picon M Vichy and V Thirion-Merle ldquoCar-acterisation des verres de la fin de lrsquoAntiquite en Mediterraneeoccidentale lrsquoemergence de nouveaux courants commerciauxrdquoin Echanges et Commerce du Verre dans le Monde Antique DFoy and M D Nenna Eds Actes du Colloque de lrsquoAssociationFrancaise pour lrsquoArcheologie du Verre Aix-en-Provence etMarseille June 2001 pp 41ndash85 Monique Mergoil MontagnacFrance 2003

[23] D Rosenow and T Rehren ldquoHerding cats Roman to LateAntique glass groups from Bubastis northern Egyptrdquo Journal ofArchaeological Science vol 49 no 1 pp 170ndash184 2014

[24] P Mirti A Casoli and L Appolonia ldquoScientific analysis ofroman glass from augusta praetoriardquo Archaeometry vol 35 no2 pp 225ndash240 1993

[25] A Silvestri G Molin and G Salviulo ldquoRoman and medievalglass from the Italian area bulk characterization and relation-ships with production technologiesrdquo Archaeometry vol 47 no4 pp 797ndash816 2005

[26] A Silvestri S Tonietto and G Molin ldquoThe palaeo-Christianglass mosaic of St Prosdocimus (Padova Italy) archaeometriccharacterisation of lsquogoldrsquo tesseraerdquo Journal of ArchaeologicalScience vol 38 no 12 pp 3402ndash3414 2011

[27] F Gallo and A Silvestri ldquoMedieval glass from Rocca di Asolo(northern italy) an archaeometric studyrdquoArchaeometry vol 54no 6 pp 1023ndash1039 2012

[28] F Gallo A Marcante A Silvestri and G Molin ldquoThe glass ofthe ldquoCasa delle Bestie Feriterdquo a first systematic archaeometricstudy on Late Roman vessels from Aquileiardquo Journal of Archae-ological Science vol 41 pp 7ndash20 2014

[29] S Maltoni T Chinni M Vandini E Cirelli A Silvestri andG Molin ldquoArchaeological and archaeometric study of the glassfinds from the ancient harbour of Classe (Ravenna-Italy) newevidencerdquo Heritage Science vol 3 no 1 article 13 2015

[30] A Ceglia P Cosyns K Nys H Terryn H Thienpont and WMeulebroeck ldquoLate antique glass distribution and consumptionin Cyprus a chemical studyrdquo Journal of Archaeological Sciencevol 61 pp 213ndash222 2015

[31] N Schibille A Sterrett-Krause and I C Freestone ldquoGlassgroups glass supply and recycling in late Roman CarthagerdquoArchaeological and Anthropological Sciences pp 1ndash19 2016

[32] A Cholakova T Rehren and I C Freestone ldquoCompositionalidentification of 6th c AD glass from the Lower DanuberdquoJournal of Archaeological Science Reports vol 7 pp 625ndash6322016

[33] S Conte T Chinni R Arletti and M Vandini ldquoButrint(Albania) between eastern and western Mediterranean glassproduction EMPA and LA-ICP-MS of late antique and earlymedieval findsrdquo Journal of Archaeological Science vol 49 no1 pp 6ndash20 2014

[34] I C Freestone S Wolf and M Thirlwall ldquoThe production ofHIMT glass elemental and isotopic evidencerdquo inAnnales du 16eCongres de lrsquoAssociation Internationale pour lrsquoHistoire du Verre(AIHV rsquo05) pp 153ndash157 London UK 2005

[35] M D Nenna M Picon and M Vichy ldquoAteliers primaries etsecondaries en Egypte a lrsquoepoque greco-romainerdquo in La Routedu Verre Ateliers Primaires et Secondaires du Second Millenaireav J-C au Moyen Age M D Nenna Ed vol 33 pp 97ndash112Travaux de la Maison de lrsquoOrient Mediterraneen 2000

[36] C M Jackson ldquoMaking colourless glass in the Roman periodrdquoArchaeometry vol 47 no 4 pp 763ndash780 2005

[37] E V Sayre ldquoThe intentional use of antimony and manganese inancient glassesrdquo in Advances in Glass Technology Part 2 F R

14 Journal of Chemistry

Matson and G Rindone Eds pp 263ndash282 Plenum Press NewYork NY USA 1963

[38] H E Foster and C M Jackson ldquoThe composition of lateRomano-British colourless vessel glass glass production andconsumptionrdquo Journal of Archaeological Science vol 37 no 12pp 3068ndash3080 2010

[39] J Henderson ldquoThe raw materials of early glass productionrdquoOxford Journal of Archaeology vol 4 no 3 pp 267ndash291 1985

[40] B Gratuze and K Janssens ldquoProvenance analysis of glassartefactsrdquo inNon-Destructive Microanalysis of Cultural HeritageMaterials K Janssens and R Van Grieken Eds pp 663ndash712Elsevier Amsterdam The Netherlands 2004

[41] J Henderson ldquoTradition and experiment in first millenniumAD glass productionmdashthe emergence of early Islamic glasstechnology in late antiquityrdquoAccounts of Chemical Research vol35 no 8 pp 594ndash602 2002

[42] P Mirti M Pace M M Negro Ponzi and M Aceto ldquoICP-MSanalysis of glass fragments of Parthian and Sasanian epoch fromSeleucia and Veh Ardasır (Central Iraq)rdquoArchaeometry vol 50no 3 pp 429ndash450 2008

[43] P Mirti M Pace M Malandrino and M N Ponzi ldquoSasanianglass from Veh Ardasır new evidences by ICP-MS analysisrdquoJournal of Archaeological Science vol 36 no 4 pp 1061ndash10692009

[44] J Hoefs Stable Isotope Geochemistry Springer Berlin Ger-many 5th edition 2004

[45] A Silvestri G Molin and G Salviulo ldquoThe colourless glass ofIulia Felixrdquo Journal of Archaeological Science vol 35 no 2 pp331ndash341 2008

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 201

International Journal ofInternational Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal ofInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

14 Journal of Chemistry

Matson and G Rindone Eds pp 263ndash282 Plenum Press NewYork NY USA 1963

[38] H E Foster and C M Jackson ldquoThe composition of lateRomano-British colourless vessel glass glass production andconsumptionrdquo Journal of Archaeological Science vol 37 no 12pp 3068ndash3080 2010

[39] J Henderson ldquoThe raw materials of early glass productionrdquoOxford Journal of Archaeology vol 4 no 3 pp 267ndash291 1985

[40] B Gratuze and K Janssens ldquoProvenance analysis of glassartefactsrdquo inNon-Destructive Microanalysis of Cultural HeritageMaterials K Janssens and R Van Grieken Eds pp 663ndash712Elsevier Amsterdam The Netherlands 2004

[41] J Henderson ldquoTradition and experiment in first millenniumAD glass productionmdashthe emergence of early Islamic glasstechnology in late antiquityrdquoAccounts of Chemical Research vol35 no 8 pp 594ndash602 2002

[42] P Mirti M Pace M M Negro Ponzi and M Aceto ldquoICP-MSanalysis of glass fragments of Parthian and Sasanian epoch fromSeleucia and Veh Ardasır (Central Iraq)rdquoArchaeometry vol 50no 3 pp 429ndash450 2008

[43] P Mirti M Pace M Malandrino and M N Ponzi ldquoSasanianglass from Veh Ardasır new evidences by ICP-MS analysisrdquoJournal of Archaeological Science vol 36 no 4 pp 1061ndash10692009

[44] J Hoefs Stable Isotope Geochemistry Springer Berlin Ger-many 5th edition 2004

[45] A Silvestri G Molin and G Salviulo ldquoThe colourless glass ofIulia Felixrdquo Journal of Archaeological Science vol 35 no 2 pp331ndash341 2008

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 201

International Journal ofInternational Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal ofInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of

Submit your manuscripts athttpswwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 201

International Journal ofInternational Journal ofPhotoenergy

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Carbohydrate Chemistry

International Journal ofInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Chromatography Research International

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Applied ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Theoretical ChemistryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Spectroscopy

Analytical ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Quantum Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Organic Chemistry International

ElectrochemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CatalystsJournal of