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Winter 2004 Gems & Gemology - GIA · PDF fileWinter 2004 VOLUME 40, ... Natural diamond containing Ni • Chalcedony from Iran • Clinohumite ... • Unusual star and “cat’s-eye”

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VOLUME 40, NO. 4Winter 2004

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REGULAR FEATURES _____________________Lab Notes

Faceted apophyllite with “crop circles” • Luminescent “hopper” diamond • “Magnetic” natural pink diamond • Diamond with many microscopic carbonateinclusions • Unusual near-colorless synthetic diamond • Orangy brown iolite fromMadagascar • “Flashing” labradorite • Natural saltwater mussel pearls • Treated-color“golden” South Sea cultured pearls • Quartz in three colors

Gem News International

Natural diamond containing Ni • Chalcedony from Iran • Clinohumite fromTajikistan • Corundum-fuchsite-kyanite rock from India • Cristobalite and opal mix-ture from Madagascar • Jeremejevite from Madagascar • Kyanite from Tanzania • Sapphires from Afghanistan and Pakistan • Sapphires from Baffin Island, Canada• Unusual star and “cat’s-eye” sapphire • Cat’s-eye topaz from Ukraine • Triplitefrom Pakistan • Gem localities in Zambia and Malawi • Barite “spears” in fluorite • Inclusions in Arizona peridot • Double-eye chatoyant quartz • Graphite inclusionsin quartz from Brazil • Quartz with molybdenite • Rutile “moth” in quartz • Synthetic corundum with unusual color zoning • Imitation clam “pearl”

Book Reviews

Gemological Abstracts

2004 Index

The Last Page: Diamond Animation on Our Fall Cover

EDITORIAL _____________First GIA Gemological Research ConferenceAlice S. Keller

LETTERS ____________

FEATURE ARTICLES _____________The Creation of a Magnificent Suite of Peridot Jewelry:From the Himalayas to Fifth AvenueRobert E. Kane

Chronicles the making of a peridot jewelry suite, from the rough mined inPakistan to the design and manufacture of the ensemble by Van Cleef & Arpels.

An Updated Chart on the Characteristics of HPHT-Grown Synthetic DiamondsJames E. Shigley, Christopher M. Breeding, and Andy Hsi-Tien Shen

Summarizes the features of synthetic diamonds currently in the gem marketthat are grown at high pressure and high temperature (HPHT) conditions.

NOTES AND NEW TECHNIQUES ______A New Method for Detecting Be Diffusion–Treated Sapphires:Laser-Induced Breakdown Spectroscopy (LIBS)Michael S. Krzemnicki, Henry A. Hänni, and Roy A. Walters

Presents a new analytical technique for detecting the presence of berylliumdiffusion in corundum.

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s readers of this journal know, modern gemology isexpanding in many exciting directions. Although tradi-tionally rooted in mineralogy and geology, gemology

now extends into fields such as physics, chemistry, and mate-rials science. This evolution has come in response to increas-ingly sophisticated synthetic gem materials and treatments, aswell as the availability of natural gems from an ever greaternumber of sources. Much ofcontemporary research isfocused on the nondestructivecharacterization of gem materi-als to document their gemologi-cal properties and determinemeans of identification—of thegem material itself, whether it isnatural or synthetic, and thecause (natural or treated) of itscolor and other features. At thesame time, advanced geologicfieldwork at known gem locali-ties, and the documentation ofnew deposits, continues to yieldimportant insights into the origins of gems.

To explore the latest breakthroughs in gemology and related sciences, GIA will host its first-ever Gemological ResearchConference August 26–27, 2006, in San Diego, California, at theManchester Grand Hyatt Hotel. This event, held in conjunctionwith the 4th International Gemological Symposium (August27–29), is being co-chaired by two prominent G&G authors andeditors, Dr. James Shigley and Brendan Laurs. The Conferencewill not only provide an international forum for gemologists toshare the results of their latest studies, but it will also give scien-tists and specialists from other disciplines an opportunity to contribute to modern gemological research. GIA hopes to holdsubsequent research conferences on a regular basis.

The following six general themes (scheduled in two parallelsessions) will be addressed at the 2006 conference:

• Gem Characterization Techniques • Diamond and Corundum Treatments • Laboratory Growth of Gem Materials • Geology of Gem Deposits • New Gem Occurrences • General Gemology (including Pearls)

Each session will feature invited lectures and submitted pre-sentations by prominent gemologists and other researchersfrom around the world, plus opportunities for interactive

discussions with audience members. In addition, a poster session will take place on August 27, for which participantscan submit innovative research on any topic of gemologicalinterest. Poster session presenters will be encouraged toshow samples, with gemological microscopes available foruse. Poster presenters may also leave their exhibits up forviewing during the International Gemological Symposium,

which will follow immediately.

Potential presenters are asked tosubmit an abstract in electronicformat by March 1, 2006.Abstracts for oral presentationsshould be submitted to the organizing committee at [email protected] for poster presenta-tions, and requests for informa-tion on poster guidelines, shouldbe submitted to Dona Dirlam [email protected]. Abstracts forboth oral and poster presenta-

tions given at the research conference will be published byGems & Gemology in a special Proceedings volume.

The science of gemology is the key to preserving the integrityof the gem industry. As new treatments and synthetics areintroduced, and new gem materials appear in the market-place, we must develop the intellectual resources to addressthem. The GIA Gemological Research Conference will helpshape the future of our science.

I urge you to join us in San Diego in 2006 for both theGemological Research Conference and the InternationalGemological Symposium. For more information on participat-ing as a presenter or attendee at the Conference, visit G&Gonline at www.gia.edu/gemsandgemology and click on theGemological Research Conference link, or send an e-mail [email protected]. Regular updates on this Conferenceand the 4th International Gemological Symposium willappear on GIA’s Web site at www.gia.edu.

You, too, can help shape the future of gemology.

Alice S. KellerEditor-in-Chief

A

First GIA Gemological Research ConferenceWill Kick Off 2006 International Gemological Symposium

EDITORIAL GEMS & GEMOLOGY WINTER 2004 283

LETTERS GEMS & GEMOLOGY WINTER 2004 285

Photoluminescence Peak in Synthetic Diamonds Due to Ruby Inclusions?In the Summer 2004 G&G (pp. 128–145), Shigley et al.reported on a comprehensive study of colored syntheticdiamonds distributed by Chatham Created Gems. In thisarticle, the authors ascribe a photoluminescence featureat 693 nm seen in the pink synthetic diamond samples toa nickel-related defect. I assume this is because, in theirreferences, A.M. Zaitsev (Optical Properties of Diamond:A Data Handbook, Springer Verlag, Berlin, 2001) quoteda center at 693.7 nm that was ascribed to nickel by V.A. Nadolinny.

I would like to suggest that there is ample evidencethat what the authors have probably seen is, in fact, theCr3+ ruby doublet, such as that seen in near-colorless syn-thetic diamond and documented on my Web site atwww.gis.net/~adamas/raman.html.

The authors state that the synthetic pinks they exam-ined were type IIa (Ib’s with low nitrogen) and containedmetallic inclusions. This is consistent with the charac-teristics of near-colorless synthetic diamonds, which usealuminum as a nitrogen getter. The getter seems toresult in precipitation of the flux into the crystal as wellas eliminating the nitrogen, and where you have alu-minum, you typically create oxides, trapping oxygen.The use of low-purity iron and nickel for a catalyst is asource of trace chromium, all the necessary ingredientsfor the formation of Al2O3 + Cr3+, i.e., ruby.

At room temperature, the ruby doublet exists at692.9 nm (1.789 eV) and 694.3 nm (1.785 eV), with theprimary luminescence peak shifting with decreasingtemperature to 693.4 nm (1.788 eV; see M. J. Weber,Handbook of Laser Wavelengths, CRC Press, BocaRaton, Florida, 1999).

K. Iakoubovskii and G. J. Adriaenssens’s high-resolu-tion photoluminescence data on a Co-grown syntheticdiamond (“Comment on ‘Evidence for a Fe-related defectcentre in diamond,’” Journal of Physics: CondensedMatter, Vol. 14, No. 21, 2002, pp. 5459–5460) andAdamas Gemological Laboratory’s lower-resolution (0.35nm quantization/pixel) SAS2000 photoluminescencedata on multiple samples and multiple-sourced Ni-Fecatalyst near-colorless synthetic diamonds, clearly showthe presence of this “ruby” doublet.

Possibly because of the very, very strong laser-induced broad-band fluorescence in the two samples of

Chatham pink synthetic diamonds I have, I have notbeen able to personally resolve the 693 nm featureusing either 488, 514, or 532 nm excitations. This mayalso be due to the requisite low integration times,although the authors noted that the feature was “rare,”occurring in less than one-third of the samples tested,somewhat consistent with our statistics (see web pageabove) on the feature in near-colorless synthetic dia-mond. It would be interesting to know whether, in theauthors’ samples tested, there was a correlationbetween fluorescence strength and observability of the693 nm feature.

Martin D. HaskeBrookline, Massachusetts

Reply

We appreciate the opportunity to respond to Mr. Haske’scomments, but we disagree with his suggestions. Uponcloser inspection (see figure 1), the luminescence feature

LETTERSLETTERS

Figure 1. These photoluminescence spectra (takenunder identical conditions at 77 K) show the classic“ruby doublet” in corundum at 692.0 and 693.4 nm(top) and a different peak at 694.2 nm in a pink syn-thetic diamond (bottom). The ruby doublet is due tochromium fluorescence, while it is likely the synthet-ic diamond peak is due to nickel impurities.

286 LETTERS GEMS & GEMOLOGY WINTER 2004

in the pink synthetic diamond spectrum is centered at694.2 nm, and it lacks a doublet peak at shorter wave-lengths. For comparison, a corundum sample was ana-lyzed under identical conditions (i.e., the same instru-ment and collection parameters and at 77 K; mostcorundum—from near-colorless varieties to ruby—con-tains at least small amounts of chromium and thus canexhibit Cr fluorescence peaks at the same positions,depending on the temperature). The position and struc-ture of the chromium fluorescence peaks are very differ-ent from the 694.2 nm peak in the pink synthetic dia-monds reported in our article. Given the currently avail-able information, the closest, most reasonable correla-tion for this feature is the 693.7 nm peak attributed tonickel in Zaitsev (2001). Admittedly, the general under-standing of photoluminescence features in diamond isevolving, and future research may provide additionalinformation on specific peak positions and causes. Also,we know of no confirmation by other analytical tech-niques of the occurrence of ruby within submicroscopicinclusions in synthetic diamonds.

While not stated directly in his letter, Mr. Haske sug-gests on his Web site that this same luminescence featuremay be useful as an identification criterion for low-nitro-gen synthetic diamonds. We believe this suggestion toalso be problematic. This luminescence feature, if inter-preted correctly as being due to ruby, is completely inclu-sion and flux-metal dependent. Unlike other more practi-cal identification features that are based on propertiesintrinsic to the synthetic diamond or the HPHT growthprocess (such as color and fluorescence zoning), the occur-rence of this so-called “Cr3+ fluorescence” depends solely

on the quantity of inclusions present and the compositionof the flux metals used. These two factors vary widelybetween manufacturers, and even between growth runs ata single manufacturer, making this feature unreliable andinappropriate as a means of identification. Furthermore,as indicated by Iakoubovskii and Adriaenssens, the analy-sis spot location (i.e., its proximity to inclusions) dictateswhether or not “chromium fluorescence” is observed in adiamond.

Perhaps even more problematic is the fact that inclu-sions of corundum in natural diamond have been reportedon occasion (see, e.g., H. O. A. Meyer and E. J. Gübelin,“Ruby in diamond,” Fall 1981 Gems & Gemology, pp.153–156; E. J. Gübelin and J. I. Koivula, Photoatlas ofInclusions in Gemstones, ABC Edition, Zurich, 1986, p. 97). GIA is currently working with a natural colorlessdiamond that contains several blue sapphire inclusions.Figure 2 shows a photoluminescence spectrum collectednear one of the corundum inclusions in this diamondusing the same operating conditions as used for the spectra in figure 1. In addition to the common diamondpeaks, a distinct chromium fluorescence doublet at 692.0and 693.4 nm is present. The fact that these spectral features can be detected in natural diamonds sheds addi-tional doubt on their reliability for synthetic diamondidentification.

James E. ShigleyChristopher M. Breeding

Andy Hsi-tien Shen

Patents on Treatment Processes for Certain Colored Synthetic Diamonds The colored synthetic diamonds described by J. E.Shigley and co-authors (Summer 2004, pp. 128–145)include both as-grown samples (especially yellow, blue,and green of type Ib, type IIb, and a mixed Ib + IIb type)and those that were treated after crystal growth (espe-cially green and pink type Ib). Unfortunately, no detailsof the irradiation or irradiation-plus-heat treatment pro-cedures were given.

Thus, it is worth mentioning that the processes ofcreating various colors in type Ib synthetic diamondsby irradiation and subsequent heat treatment aredescribed in detail in a series of Japanese (JP), European(EP), German (DE), and United States (US) patent docu-ments, all with priority dates in the late 1980s–early1990s and all assigned to Sumitomo Electric Industries,Osaka, Japan.

Detailed production information for the following col-ors is described in these patents:

• Purple: JP 01-131014A, EP 0 316 856 A1, DE 38 78 532T2, US 4,950,463, priority date November 17, 1987

• Bluish green: JP 01-138112 A, November 25, 1987• Green: JP 01-183409 A, EP 0 324 179 A1, DE 38 75 604

Figure 2. The photoluminescence spectrum of a natu-ral colorless diamond with corundum inclusionsshows a distinct chromium fluorescence doublet at692.0 and 693.4 nm. Thus, while this feature has alsobeen observed in some synthetic diamonds, it shouldnot be considered diagnostic.

LETTERS GEMS & GEMOLOGY WINTER 2004 287

T2, US 4,959,201, January 13, 1988• Red and pink: JP 06-263418 A, EP 0 615 954 A1, March

15, 1993.

In a first step, irradiation of type Ib synthetic dia-monds is performed by electrons in the 2–4 MeV energyrange (to obtain a purple, bluish green, or green color) orin the 1–10 MeV energy range (to obtain red or pink).Subsequently, the synthetic diamonds are annealed in avacuum at temperatures of 550–600°C (bluish green),800–1100°C (purple), 1500–1800°C (green), 600–800°C(red), and 800–1100°C (pink). The production of variousdefect centers (e.g., H2, H3, H4, GR1, and N-V), whichare responsible for the different colorations, is alsodescribed in detail.

These patent documents may be helpful in under-standing the mechanism of color formation and theproperties of these treated type Ib synthetic diamonds,and in completing the knowledge necessary for a separa-tion of natural and synthetic samples. For furtherdetails, the reader is referred to the documents cited,which are available via the Internet from the respectivepatent offices.

Karl SchmetzerPetershausen, Germany

Cut Article Recognizes Contributions of “Outside” EffortsI very much enjoyed the article, “A Foundation forGrading the Overall Cut Quality of Round Brilliant CutDiamonds” in the Fall 2004 G&G (pp. 202–228). I espe-cially appreciated the references to contributions fromamateurs Bob Long, Norm Steele, and Bob Strickland. Thearticle is top notch.

Reading this article called to mind a visit I made to theHenry Ford Museum in Detroit, Michigan. One aim oftheir exhibits is to show how technology evolves withtime. There are wheat harvesting machines in a line rang-ing from the earliest models to the most current. The samecan be said for several other exhibits, such as milk purifica-tion machines, artificial lights for cameras, and locomo-tives. The one lesson that is apparent from these exhibits isthat steady improvements usually come from people insidetheir field. It is the dramatic jumps in technology thatcome from the fringe players outside of the mainstream. Sothe world is a result of both types of contributions. Gems& Gemology recognizes both, and I couldn’t be happier.

Thanks once again for such a great journal as G&G.Bob Ayres

Birmingham, Michigan

ssembling even one matched pair of gems for earrings can be a difficult process.Assembling an elaborate matched suite—

for a necklace, bracelet, ring, and earrings—is theultimate challenge. Typically, a matched suite iscompiled by selecting gems that have essentially thesame color, clarity, dimensions, and cutting propor-tions from a large group of faceted gems. The greaterthe number of gems to choose from (e.g., hundredsto thousands), the faster a large or intricate matchedsuite can be assembled. Elaborate suites may takeyears to complete if they are not intentionally cutfrom the rough. As gems of the appropriate size,shape, color, and clarity are purchased or come fromthe cutting factory, they are added one at a time tothe suite. Re-cutting of gems that are close inappearance is often necessary. Only rarely does agem dealer–cutter have the opportunity, take thetime, or incur the cost to intentionally fashion alarge set of precisely matched gemstones for a jewel-ry ensemble from a large parcel of rough.

This article describes and chronicles the makingof just such an ensemble, the magnificent peridot,diamond, and platinum jewelry suite shown on thecover and in figure 1. The availability of a continued

supply of large, fine peridots from a relatively newlocality in Pakistan provided the material needed tocompile the stones for this suite, which wereexpertly preformed and faceted by two mastercraftsmen. Although many excellent books and arti-cles explain the details of jewelry manufacture (see,e.g., Untracht, 1982; Revere, 2001), few also explorethe intricacies of creating a suite of haute couturejewelry, as is provided here by a unique visit to theworkshops at Van Cleef & Arpels. This article takesthe reader from the mines high in the HimalayaMountains of Pakistan, through the assessment ofthe rough and the cutting of the faceted gems, to thedesign and creation of the final jewelry suite.

THE SAPAT VALLEY PERIDOT DEPOSIT IN PAKISTANIn the early 1990s, the famous Arizona peridotmines supplied 80–95% of the world’s peridots;

288 PERIDOT JEWELRY SUITE GEMS & GEMOLOGY WINTER 2004

A

THE CREATION OF A MAGNIFICENT SUITE

OF PERIDOT JEWELRY: FROM THE HIMALAYAS TO FIFTH AVENUE

Robert E. Kane

See end of article for About the Authors and Acknowledgments.GEMS & GEMOLOGY, Vol. 40, No. 4, pp. 288–302.© 2004 Gemological Institute of America

The ultimate value of a gemstone suite lies not only in the cost and quality of the materialsthemselves, but also in the selection of the rough, the quality of the faceting, and the intricacyof the setting in a well-designed and well-manufactured suite of jewelry. This article chroniclesthe creation of a fine suite of peridot jewelry from the mine in the Himalayas to the manufac-ture of the necklace, bracelet, ring, and earrings. Eight kilograms (40,000 carats) of peridotrough from the Sapat Valley region of Pakistan was purchased in early 2004. Following theassessment of the rough, careful preforming and faceting produced a precisely matched suite ofAsscher-cut peridots. The suite comprises 54 gems ranging from 3.57 to 18.30 ct, for a totalweight of 350.40 ct. Van Cleef & Arpels in Paris designed the jewelry, and the New York ate-lier of Van Cleef & Arpels manufactured the five pieces.

most of these weighed less than 1 ct, and only rarelydid they reach 3 ct (Federman, 1992). AlthoughBurma/Myanmar has long been known to producesome beautiful large faceted peridots (as, historical-ly, has Egypt), such stones have never been consis-tently available in large quantities.

In 1994, however, extraordinary amounts of fine,large gem peridot entered the international gem andmineral markets (Koivula et al., 1994a; Federman,1995; Milisenda et al., 1995; Frazier and Frazier,1997). This new source of peridot was in Pakistan:near Sapat Nala, in the Sapat Valley, Mansehra dis-trict, North West Frontier Province (Kausar andKhan, 1996; Hammer, 2004—see figure 2).According to Jan and Khan (1996, p. 17), “the peridotoccurs in pockets and veins located in shear zones inpartially serpentinized dunitic host rocks.” Themine is situated in the western HimalayaMountains at an elevation of 4,500 m (15,000 feet)above sea level. Koivula et al. (1994a) reported thatthe mine could be reached by a seven-hour horse-back ride and a two-day hike from the closest popu-lated area, Basham Village. The typical routethrough the Jalkot Valley to the mine is potentiallyvery dangerous and not recommended for nonlocals.

This discovery—along with current production ofsmaller stones from China, Vietnam, Ethiopia,Tanzania, and Myanmar, as well as Arizona—hastransformed peridot into even more of a “main-stream” gemstone for jewelry manufacture aroundthe world. The Pakistani peridot is far cleaner andlarger than the Arizona material and typically ismore uniform in color than the Burmese material.One of the author’s international manufacturing sup-pliers reported faceting nearly half a million carats ofArizona peridot during the last 15 years, with nomore than a handful of clean (nearly flawless) stonesover 10 ct produced; the average size of relativelyclean faceted stones was about 2 ct. However, overthe last three years, his operation has faceted morethan 30,000 carats of Pakistani peridot; 35% of theproduction has been over 5 ct, with nearly one thirdof these in the 10–20 ct range. The author has evenseen the occasional faceted peridot from Pakistanthat exceeded 100 ct. As an additional example of theprolific nature of this mine, the author recentlyexamined a beautiful, well-matched Pakistani peridotnecklace, ring, and earring suite comprising 16faceted peridots with a total weight of more than 400ct. The continued production of large, fine pieces of

Figure 1. This unique suiteof peridots and diamonds

set in platinum wasdesigned and manufac-

tured by Van Cleef &Arpels. The necklace con-tains 31 faceted peridots

ranging from 3.78 to 13.78ct, with a total weight of228.22 ct; the ring stone

weighs 18.30 ct; the peri-dots in the earrings range

from 3.57 to 4.55 ct, with atotal weight of 24.31 ct,

and the bracelet contains16 matching peridots

weighing a total of 79.57ct. The custom-cut

Pakistani peridots wereprovided by Fine GemsInternational, Helena,

Montana. The diamonds(D-E color, VVS clarity)

were supplied by Van Cleef& Arpels. Photo by Harold

& Erica Van Pelt.

PERIDOT JEWELRY SUITE GEMS & GEMOLOGY WINTER 2004 289

rough from Pakistan has had a significant impact onthe jeweler’s ability to create attractive designs con-taining numerous large matched peridots.

GEMOLOGY OF PERIDOT FROM PAKISTANAs noted above, peridot from Pakistan often occursas large gemmy crystals. With the exception of theoccasionally occurring black acicular inclusions ofludwigite-vonsenite, which are unique to peridotfrom Pakistan (Koivula et al., 1994b; Milisenda etal., 1995; Peretti and Gübelin, 1996), the gemologi-cal properties of Pakistani peridot are consistentwith those of peridot from other geographic locali-ties. They are summarized in table 1.

ASSESSMENT AND ACQUISITION OF THE PERIDOT ROUGH Eight kilograms (40,000 carats) of gem-quality peri-dot rough from the Sapat Valley, Pakistan, was pur-chased in February 2004 by an experienced manu-facturer. Figure 3 shows some of the larger piecesfrom this parcel, which yielded a number of thegems in the jewelry suite. Sellers of gem rough typi-cally start with a high asking price, recognizing thatthey will have to negotiate down. The purchasermust carefully study each piece in the parcel, deter-mining the shape, size, and cutting yield, as well asmarket demand and the potential selling price ofthe cut gems, before making an offer. An accurateassessment and a little luck can produce a profit; amiscalculation can result in a loss.

Many of the steps in determining the yield andpotential value of the faceted gemstones expected

from a rough parcel overlap and are repeated duringthe sawing and preforming stages (see below). Oncethe identity of the gem mineral is established (again,see table 1), the rough is examined for color, trans-parency, and inclusions. Some dealers use a light-box (again, see figure 3), while others use only aportable, high-intensity flashlight such as one utiliz-ing a xenon light bulb and lithium batteries. Thelatter produces reliable results in either the field orthe office. (For more information on identifyinggems in the field, see Boehm, 2002.)

290 PERIDOT JEWELRY SUITE GEMS & GEMOLOGY WINTER 2004

Figure 2. The peridotdeposit is located in theSapat Valley, Mansehradistrict, North WestFrontier Province,Pakistan, about 240 km(by air) north-northeastof Peshawar. The routethrough Jalkot Valley isdangerous and is notrecommended for nonlo-cals. Note that certainborders in this area arein dispute.

TABLE 1. Properties of peridot from Pakistana.

Property Description

Refractive indicesb nx = 1.648–1.653ny = 1.663–1.671nz = 1.683–1689

Birefringenceb 0.035–0.038Specific gravityb 3.29–3.37Spectroscope spectra Typical peridot Fe2+ absorptionb: distinct,

yet diffuse absorption bands at about 453, 477, and 497 nm, as well as a weaker band at about 529 nm (the last often seen only in large stones)c

Internal features Acicular inclusions of ludwigite-vonseniteb,c,d; veils (fingerprints, feathers)composed of tiny fluid inclusions, and growth structuresb

aThe gemological properties of Pakistani peridot are consistent withthose of peridot from other geographic localities, with the exceptionof the ludwigite-vonsenite inclusions (which have not been reportedin peridot from any other locality).bMilisenda et al., 1995.cKoivula et al., 1994b.dPeretti and Gübelin, 1996.

It is important to note that while artificial light isideal for assessing inclusions, natural daylight isvital when judging color quality. Estimating thecolor of the completed faceted gem requires a thor-ough understanding of the relationship between thecolor observed in the rough crystal and the final face-up color. An excellent discussion on this difficultand complicated subject, as well as other aspects ofevaluating gem rough, can be found in Sevdermishand Mashiah (1996). However, when assessing gemrough, there is no substitute for years of experience.

By carefully studying the 8 kg of peridot rough, itwas estimated that a 20% recovery of faceted gems(or 8,000 carats) could be produced. Although therewere many large pieces of rough (up to 35 g), thepresence of inclusions and fractures in nearly all thelarge crystals meant they would need to be sawninto smaller pieces. Therefore, it was expected that8–10% of the cut gems would weigh under 1 ct;10–15% would weigh 1–2 ct, 40–50% would weigh2–5 ct, and the remaining approximately 25–40%would be stones in the 5–20 ct range. The finalaverage yield of approximately 6,500 ct of facetedstones was 16.2%, slightly lower than the originalestimate. Of special significance to this article, theauthor and the manufacturer decided that anextraordinarily well-matched suite of gems could becut from the parcel due to the uniformity of color.

DESIGNING THE GEMSIf properly executed, the cut of a gemstone showcas-es the gem’s inherent beauty in vibrant color andradiating brilliance. A skilled cutter, or lapidary, cantake a seemingly unattractive piece of rough andtransform it into a beautiful gemstone. Likewise, anunskilled lapidary can ruin a stone with poor cut-ting and color orientation, resulting in a dull,unattractive, misshapen gem. Excellent cutting—inboth planning and execution—is therefore essentialto bringing out the maximum beauty of a gemstone.

A good gem cutter typically fashions a piece ofrough for maximum weight retention, while alsotrying to maximize beauty. This is frequently anongoing struggle, as the cutter must strike a balancebetween beauty—which depends on proper cuttingproportions, symmetry, and color orientation—andthe higher price that a greater weight may bring.Preforming (or pre-shaping), the process of grindinga piece of rough into the approximate shape of thefinished stone, is a critical step in maximizing thevalue of a parcel of rough. In fact, many successful

buyers of gem rough are exceptional preformers, andwill often personally pre-shape most or all of theparcels of rough they purchase.

The initial steps in the processing of coloredstones and diamonds differ significantly. In the“manufacture” of diamonds, a master cutter (ormarker) marks the precise cleaving and/or sawinglocations on the exterior of the rough diamond crys-tal using indelible ink (“India ink”). Thereafter, thevarious processing steps are carried out by differentindividual professionals, such as the sawyer,cleaver, bruter, and polisher (see, e.g., Watermeyer1991; Sevdermish and Mashiah, 1996; Caspi, 1997).

In contrast, the colored stone preformer ordesigner alone typically undertakes nearly all of theprocessing steps. With many colored gems, thisincludes breaking (cobbing) or cleaving (of thosegems having cleavage), sawing, preforming, andgirdling (shaping). Once the preform is produced, itis turned over to the master cutter. He or she isresponsible for the placement of the facets andachieving the final polish.

Most of the original 8 kg of peridot rough waspreformed in the United States by the manufactur-er, who is also a master preformer. The peridots pre-pared for the jewelry suite described in this article,as well as many other large and important stones

Figure 3. This representative selection shows 330 g(1,650 ct) of the larger peridot pieces from the 8 kg(40,000 ct) parcel, from which some of the gems seenon the cover and in figure 1 were cut. The rough hasbeen placed on a light-box (typically composed of atranslucent white plastic top, illuminated frombelow with fluorescent lighting), which is often usedto evaluate colored gem rough. Photo by Jeff Scovil.

PERIDOT JEWELRY SUITE GEMS & GEMOLOGY WINTER 2004 291

from the same parcel, were faceted by a European-trained master cutter with 30 years of faceting expe-rience, who now lives in the U.S. Most of theremaining stones were cut in China.

The major design element of the matched peri-dot suite—the shape, size, and number of gems—was decided early in the preforming process. The

Asscher cut (an early emerald cut with very widecorners, a high crown, and a deep pavilion) wasselected for its classic look. Although this cuttingstyle accentuates color and brilliance, it also high-lights any inclusions present in the gem. Therefore,it was critical that only loupe-clean pieces of roughbe used. As the necklace suite neared completion, atrapezoid shape was added as the “center” stone toadd interest to the design.

Examination and Marking of the Peridot Rough. Theperidot rough was first sorted into parcels based onsize. Each size-specific parcel was next examined ona fluorescent light-box and sorted again for clarityusing the unaided eye. Then, each piece of peridotrough was held very close to an intense incandescentlight source. A bright, bare light bulb can be used forthis last step, but many professionals prefer a fiber-optic light. Gently rotating the piece of rough, thepreformer observes the colors from different direc-tions; locates fractures and solid inclusions; and visu-alizes the final shape, size, and table location of thefinished gem. The location of the table is critical indetermining the face-up color of many faceted gems,because in pleochroic gem materials different colorsare seen in the different crystallographic directions.

From this initial evaluation, the preformer canoften predict the final weight and monetary value ofthe completed gemstone—in many cases, even

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Figure 5. Sawing is one of the most important steps ingem cutting. The first series of cuts are made throughcracks or veils (“fingerprints”) in the rough. Here, thepreformer uses a high-speed, liquid-cooled saw with a0.2 mm thick diamond blade on one of the peridots.Photo by Jeff Scovil.

Figure 4. These diagrams illustrate various preformdecisions that might be made during the sawing pro-cess. The red dashed lines show where the stoneswould be marked for saw cuts; the white dashed linesindicate the shapes of the gems that would be fash-ioned from the resulting pieces. Image 1 shows thesawing direction through a veil. Image 2 shows athick crystal that could be sawn into two pieces fromwhich matching emerald cuts might be faceted. Indiagram 3, the red dashed line indicates where thispiece would be sawn to remove the included sectionon the right. The elongated pear shape in 4a might bedifficult to sell, so the preformer could decide to cuttwo smaller gems (4b). In diagram 5, four possiblechoices are shown for the same piece of rough; factorssuch as depth, cavities or indentations, and inclusionscould influence the final decision. Adapted fromSevdermish and Mashiah (1996).

before the first saw cut or grinding. Much of thisassessment is done without the aid of magnifica-tion, although some preformers use a head-loupe,such as an OptiVisor. During this process, the pre-former uses indelible ink to mark areas containinginclusions, deep indentations, and cavities that needto be sawn away, usually directly along fracturesand veils, and to plan the final gems (figure 4).

Cobbing of Gem Rough. Another method of remov-ing poorly colored, opaque, included, and/or frac-tured material (as well as other adhering minerals ormatrix) from facetable gem rough is cobbing. Thiscan be done by striking the rough with a small metalhammer to remove unwanted areas (Epstein, 1988)or by using a specially designed pair of steel pliers. Ifthe unwanted area does not traverse the piece ofrough, pliers are not used because facetable areasmay be accidentally crushed or removed. These situ-ations call for the use of a trim-saw (Sevdermish andMashiah, 1996). Many preformers prefer to use onlya saw with expensive gem rough, because it is farmore controllable. All of the peridot rough describedin this project was trimmed with a saw.

Sawing the Peridot Rough. Following the ink mark-ings (again, see figure 4), the lapidary makes the first

cuts using a high-speed, liquid-cooled saw with asintered diamond blade (figure 5). The blades usedfor the peridot were a mere 0.2 mm thick. Althoughsomewhat difficult to maneuver (they bend very eas-ily, causing the saw cut to stray off the marked line),these thin blades save material and improve yield.

Next, the preformer evaluates each piece ofsawn rough to determine if additional saw-cuts arenecessary to produce finished stones with a mini-mum of weight loss. This is done by again holdingthe sawn piece up to a bright light to check for anyremaining inclusions. If inclusions are still present,the preformer decides whether to remove them bysawing or grinding. Some rough requires multiplesaw cuts to produce the desired shape.

Most gem cutters believe that sawing is the mostimportant step in controlling the yield of the rough.Once the sawing of the peridots was completed, allthe pieces that lent themselves to Asscher cuts wereselected out of the parcel.

Grinding the Preforms. At this stage, the pre-former again examines each piece of sawn rough todetermine the ideal shape and proportions that canbe cut from it (figure 6). As has been pointed out,in many cases this is an ongoing struggle and com-promise between weight retention and beauty. In

Figure 6. At the pre-forming stage, the pre-former visualizes theshape, proportions, andtable location of the fin-ished gem. These ideal-ized diagrams illustratethe transition fromrough to finished pre-form for three popularshapes. Adapted fromSevdermish andMashiah (1996).

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creating the peridot jewelry suite, weight retentionwas much less of a consideration, since the intentwas to create the most precisely matched set pos-

sible from the original parcel. The beauty, unique-ness, and rarity of such a suite would more thancompensate for the reduced yield.

The next step in the preforming processinvolves grinding the sawn rough into the approxi-mate shape of the finished gem (figures 7 and 8). Inthis case, three diamond-impregnated wheels—coarse, medium, and fine grit—were used to pre-form the peridot rough.

Some of the questions the preformer must consid-er are: Will the culet meet the edge of the rough so asto have the proper total depth, while not wasting toomuch material? (If not, another shape must be creat-ed from this particular piece of rough, and anothersawn piece must be chosen for the jewelry suite.)Will the face-up color orientation match the color ofthe rest of the suite? Is there enough material underthe proposed table to enable cutting the properangles, so that the gem will not be too shallow orwindowed? (If not, a smaller stone must be shaped.)

If the stone has great value—for example, a largenatural-color ruby—the preformer may first grindthe table into place and give the rough to the cutterto polish the table. This enables a clear view intothe stone so that a better assessment of color,including distribution and clarity, can be madebefore the rest of the stone is preformed.

After the table is in place, the sawn rough isground into the desired shape. While it does nothave to be perfect, it does need to follow closely theshape and proportions desired for the final facetedgem (again, see figures 6 and 8). With the peridotsuite, care was taken to ensure that the opposingsides of the preforms were parallel. The preformeralso made certain that all the proportions (such ascrown and pavilion angles, crown height and pavil-ion depth, table size, even girdle thickness, etc.)were consistent from one preform to the next.Minor corrections needed for these proportionscould be made later by the faceter.

Any cracks and inclusions not removed duringthe sawing process are dealt with at this stage. Theperidot suite required very clean stones, so all (ornearly all) inclusions were sawn or ground out ofthe preforms. However, with gem material forwhich some inclusions are allowable (such as emer-alds), or with very expensive material (such as natu-ral-color Mogok rubies), inclusions are left in thepreforms, but the cut is designed to make them asinconspicuous as possible. For example, the per-former tries not to place inclusions at or near theculet because they will reflect throughout the fin-

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Figure 8. As the preforms were completed, they werelaid out to check for consistency of color (hue, tone,and saturation) from one stone to the next and, for

the necklace, to ensure the smooth graduation fromlarge to small sizes. This photo shows the beginning

stages of this process; as more preforms were com-pleted they were added, and some (including a few ofthose shown here) were removed. Photo by Jeff Scovil.

Figure 7. The sawn piece of rough is then groundagainst a diamond-impregnated wheel to produce theapproximate shape and proportions of the finishedgemstone. This step is crucial to the design of thefinal gem. Photo by Jeff Scovil.

ished stone when viewed in the face-up position. Some shapes are easier to sell than others, so it is

often better to choose a more popular shape even ifit results in a greater weight loss from the originalrough. The girdles can be rough-cut by hand on thepreforming grinder (again, see figure 7), or they canbe cut using a girdle-grinding machine. The initialgirdling (shaping) of the peridots in this suite wasdone during the preforming stage.

Once the peridot suite preforms were completed,they were laid out to be sure that the hue, tone, andsaturation of the stones matched and, for the neck-lace, that the transition from large to small sizeswas smooth (again, see figure 8). The preforms forthe necklace were then sorted into “matched” pairsand delivered to the master cutter with instructionsthat each pair of opposing stones must have parallelsides and be precisely matched.

Placement and Polishing of the Facets. Several dif-ferent kinds of faceting approaches and equipmentchoices exist (see, e.g., Sinkankas, 1984;Sevdermish and Mashiah, 1996). A slightly modi-fied version of the classic Swiss jam-peg facetingsystem (with copper laps charged with diamondpowder) was used to facet this peridot suite (figure9). Although the jam-peg system is primitive inappearance, an experienced lapidary can produceextraordinarily well-cut gemstones with it, and var-ious versions have long been used by many of thefinest cutters in the world. The beauty of the sys-tem lies in the fact that it allows flexibility inchoosing facet angles and, for the experienced jam-peg cutter, it is faster than the protractor-type(index) system, in which the dop is held mechani-cally at specific angles (Sinkankas, 1984).

The jam-peg system used to facet the peridotsuite includes a dop-stick that is held in the cutter’shand. The flat end of the dop-stick, or rod, has thepreformed stone attached by either cold or hotcementing (wax also can be used, as was the casewith the peridot suite). The cutter presses the endholding the gem against the diamond-charged, hori-zontally rotating cutting lap, while the other (point-ed) end of the dop-stick is “jammed” into a chosenhole (actually a shallow depression) that corre-sponds to a particular facet angle relative to the cut-ting wheel. These holes are precisely placed in asolid surface called an arc (A in figure 10), whichwas curved metal in the case of the peridot suiteproject, although other systems employ a flat-sur-faced arc, which may be made of either wood ormetal. The arc is attached to the table by a verticalsupport. By positioning the pointed end of the dop-stick into different holes of the jam-peg arc, the cut-ter determines the angles and position of the facets.

The dividing head (C in figure 10) determines thecircumferential angles, as well as additional anglesof altitude. A simple octagonal dividing head is ade-quate for square and rectangular emerald cuts (andwas used in the cutting of the peridot suite), whereasa more complex dividing head is required for othershapes (see, e.g., Sevdermish and Mashiah, 1996).

The first step is to facet the crown. The facetsare initially formed using a rough-textured lap toremove material quickly. This generates heat, sothe rotating lap is cooled with water. The next stepis undertaken with a final cutting lap, or pre-polishlap, which removes much less material but pro-duces a slightly smoother, yet still rough surface.This allows the cutter to create all the facets at the

Figure 9. Once preformed, the pieces were delivered tothe master cutter. Shown here is the slightly modified,classic Swiss jam-peg system that was used to facetthe peridot suite. Photo by Jeff Scovil.

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desired angles and sizes. Once the crown is faceted,an ultra-high polish is achieved using a copper lapcharged with very fine diamond powder (up to50,000 grit). Because very little material is removedduring the polishing process, much less heat is gen-erated, so water for cooling is not necessary duringthis final step (for the peridots, however, oil wasmixed with the fine diamond powder).

After faceting of the crown is complete, thestone is removed from the dop-stick and cleaned ofall adhesive. It is then remounted with the dop-stick perpendicular to the table, so that the uncutpavilion is exposed and the stone is centered on thedop’s longitudinal axis. Once the stone is attachedand centered on the dop, the cutter repeats the pro-cess of placing and polishing facets. The polishing ofthe girdle is the final stage in the faceting processwhile the stone is still on the dop-stick.

Sorting, Matching, and Slight Re-Cutting of theSuite. As each matched pair (opposing stones) in thenecklace was completed, they were carefullychecked to ensure that the color and all proportionswere essentially the same. Minor deviations in pro-portions were remedied by slight re-cutting. Anyother objectionable differences would cause thestone to be rejected, and another would be cut toreplace it in the suite. The same quality-control pro-cess was undertaken for the stones in the braceletand earrings. As the finished gems were completed,they were positioned to simulate the actual jewelryset (figure 11). The layout was then evaluated toensure that hues, tones, saturations, and shapes

matched, and that there was a smooth transition insizes in the necklace.

Once we were satisfied with the 54 faceted peri-dots (which ranged from 3.57 to 18.30 ct, for a totalof 350.40 ct), the suite was ready for the next majorphase: the design of the jewelry, the cutting of thediamonds, and the manufacture of the finishedpieces.

THE DESIGN AND MANUFACTURE OF THE JEWELRY SUITEThe completed matched suite of unset peridots wassold to an American client, who desired well-designed and finely crafted jewelry. Suwa (2001)stated that the highest quality of jewelry fabrication(representing just a few percent of the total market)is accomplished by marrying a well-planned designconcept to the highest standards of craftsmanshipusing the finest materials and taking the necessarytime. A superior design is not only aestheticallypleasing, but it also results in a finished piece that iscomfortable to wear while it holds the gems secure-ly. For these peridots, the client chose Van Cleef &Arpels to design and manufacture the jewelry.

A Brief History of Van Cleef & Arpels. The venera-ble firm of Van Cleef & Arpels began in 1896, withthe marriage of Estelle Arpels, daughter of Leon, agem trader, and Alfred Van Cleef, the son of a dia-mond merchant from Amsterdam. Alfred joined hisnew brothers-in-law to create a jewelry house. Thesuccess of this collaboration allowed them to move,

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Figure 10. With the jam-peg system,the cutting angles are achieved byusing the arc as illustrated here.Image 1 is a front view of the arc,showing the precisely placed holesinto which the pointed end of the dop-stick is “jammed.” Images 2–4 showthe jam-peg process from the side,with A the arc, B the dop-stick, C theoctagonal dividing head, D the cut-ting lap, and E the gem. The positionof the dop-stick when cutting thetable of a stone is illustrated in image2, with 3 showing the position for cut-ting the crown facets (with a similarposition, but different angles, for thepavilion facets), and 4 the positionused for the girdle. Adapted fromSevdermish and Mashiah (1996).

in 1906, to the Place Vendôme in Paris, an arearenowned for its elegance and luxury, and the head-quarters remains located there today.

Van Cleef & Arpels’s clients have included roy-alty and Hollywood legends, as well as other dis-criminating clientele. In 1956, VCA was designated“official supplier to the Principality” of Monaco,and a decade later their designs were selected frommore than 50 proposals for the crown to be used atthe coronation of Farah Pahlavi, who was to marrythe Shah of Iran.

To this day, Van Cleef & Arpels is renowned forits innovative designs and techniques such as the“invisible setting,” in which the prongs are hiddenbeneath the crown of the gemstone. The companyprides itself on using only the highest-quality gemsin their superbly crafted jewelry.

Creation of the Design at the Van Cleef & ArpelsParis Atelier. A designer at the Paris atelier wascommissioned to produce two very simple yetsophisticated design renderings. The goal was tocreate a distinctive and attractive suite of jewelry toshowcase the peridots. The degree of manufacturingdifficulty was not considered as important as thefinal design.

The first illustration consisted of a moderndesign composed of uneven lateral baguette dia-monds set between the Asscher-cut peridots. Thesecond rendering, the one ultimately chosen by theclient, consists of paired baguette diamonds set par-allel to one another between the main gemstones inthe necklace, and single baguette diamonds betweenthe peridots in the bracelet and earrings, as well as inthe back of the necklace. The ring contains two rowsof baguette diamonds on each side of the shank, andbaguettes on the peridot gallery (figure 12).

Handcrafting the Jewelry at the Van Cleef & ArpelsNew York Atelier. After the design was approved,the director of production in the New York atelierconsulted his foreman to determine which jewelerswould work on which pieces of the suite (i.e., thenecklace, bracelet, earrings, or ring). The selectionwas made based on each jeweler’s particular area ofexpertise. The jewelers selected to manufacturevarious parts of the suite specialized in hand fabri-cation and, with the exception of the ring, were thein-house experts for making hinges and joiningmechanisms. Five different master jewelers workedon the suite, spending a combined total of morethan 900 hours.

Making the Settings. The suite was handmadefrom a standard platinum alloy consisting of 95%platinum and 5% ruthenium. Pure platinum issoft, whereas platinum alloys are more durableand thus increase the wearability. The settings forall of the peridots include upper and lower gal-leries (sometimes referred to as bezels) that arejoined by four prongs (figure 13). The outside mea-surements of the upper galleries were made small-er than the outer dimensions of the peridot—sothat when finished, no metal would be visiblefrom a top view except for the top portions of thetapered prongs. The upper and lower gallerieswere made from platinum sheet. Then, the prongswere made by hand using rectangular wire to fitthe gallery to the peridot at the appropriate angle.

Figure 11. The final selection of cut peridots resultedin this matched suite comprising a total weight of350.40 ct, with the 54 pieces ranging from 3.57 to18.30 ct. Photo by Harold & Erica Van Pelt.

PERIDOT JEWELRY SUITE GEMS & GEMOLOGY WINTER 2004 297

After the gallery pieces and prongs were formed,they were filed, pre-polished, and assembled (fig-ure 14). In contrast to gold, platinum is muchmore resistant to polishing because of its extremedensity. However, platinum also holds its lusterthrough assembly and soldering, so the settingsrequired minimal additional polishing during thefinishing process.

The jewelers then made the settings for thebaguette diamonds in the necklace, earrings, andbracelet. The metal consisted of two preciselyformed pieces of platinum placed on either side ofthe diamond to secure it, with a channel-type set-ting running the length of the narrow ends of thebaguettes (that, again, was the only metal visiblefrom the top view).

Creating the Hinges and Connectors. Next, thejewelers hand-fabricated the hinges and connectors(figure 15). The connection in a piece of jewelryactually marries the stones and metal. It is extreme-ly important in couture craftsmanship to hide theconnections as much as possible, so they are notvisible to the unaided eye and do not detract fromthe essence of the design.

To construct the bracelet, two platinum tubeswere attached to the peridot settings and one tothe setting for each of the baguette diamonds.Platinum hinge wires were inserted through thetubes to join the bracelet segments. After thebracelet was joined, it was flexible and smooth,moving laterally with no play and evenly follow-ing the contour of the wrist when worn.

298 PERIDOT JEWELRY SUITE GEMS & GEMOLOGY WINTER 2004

Figure 12. A color ren-dering of the jewelrysuite was created bythe Van Cleef &Arpels design team inParis. This compositeimage of the designsshows the plans forthe necklace, bracelet,ring, and earrings. © Van Cleef & Arpels.

For the necklace and earrings, special connectionswere used that when joined can move in two direc-tions, so the necklace lies comfortably on the contourof the neck and the earrings move and dangle freely.

Figure 13. The peridot settings were hand fabricatedfrom sheet and wire platinum. They are composed ofupper and lower galleries, and four prongs. The base ofthe setting, or the lower gallery, is cut out with a jew-elers saw. The bearing—a notch cut in each prongwith a setting burr—serves as a “seat” for properlypositioning and securing the gem. (Note that thisschematic diagram is to clarify terminology only; itdoes not represent the actual peridot settings.)

Figure 15. The jeweler hand-fabricates the hinges andconnectors for the suite. For the bracelet, two plat-inum tubes were attached to the peridot settings andone to the settings for the baguette diamonds.Platinum hinge wires were inserted through the tubesto “join” the bracelet; the ends were then flanged.Photo by Robert Weldon.

Figure 14. The setting (gallery and prongs) for each ofthe peridots was handmade to fit that stone. This photoshows the process underway. One tray holds the actualstones placed table-down over a color copy of the ren-dering; above this is a second tray with another copy ofthe rendering on which the settings have been placed intheir proper position. The master jeweler then files andshapes each setting by hand to ensure the proper fit ofthe specific gem (inset). Photos by Robert Weldon.

PERIDOT JEWELRY SUITE GEMS & GEMOLOGY WINTER 2004 299

The Finishing Steps. After the fabrication andassembly were completed, the jewelry items weredetailed, polished, and finished by the in-house fin-

ishing expert. This was done before the peridotsand diamonds were set, because polishing variousparts prior to assembly enables the jeweler toachieve a mirror finish on areas that would not beeasily accessible once all the gems were set.

Upon completion of the individual jewelry set-tings for the peridot suite, VCA turned to the dia-monds. To supply the precisely cut diamondsrequired, the company either had existingbaguettes recut to their specifications or had themspecially cut from the rough. Not only were thediamonds cut to the proper length, but in areaswhere the necklace curves (essentially, the fronthalf) and in the ring, the ends of many of the dia-monds also had to be fashioned to the proper angleso they would fit perfectly into the settings.Incorporated into the suite’s various jewelry piecesare more than 90 diamonds, with a total weight ofapproximately 21 carats. All are D-E color and VVSor better clarity.

After the finishing process, the settings, dia-monds, and peridots were given to two different set-ters—one for the diamonds and another, who spe-cializes in large colored stones, for the peridots (fig-ure 16). More time and care is required to set peri-dots—than, for example, sapphires—because of theironly fair to good toughness and 61/2 –7 hardness.

The colored stone setter begins by verticallytapering the outside of the prongs; the bearings arethen cut with a setting burr, and the peridot isplaced at the proper height and evenly in the prongbearings (figure 17). At this point, the prongs are

300 PERIDOT JEWELRY SUITE GEMS & GEMOLOGY WINTER 2004

Figure 16. To set the peridots, a bracelet section compris-ing three main settings, with baguette diamonds separat-ing the peridots, was put into a shellac stick on the end ofa wooden handle. This stick allows the jeweler to firmlyhold the section in one hand, while setting the gemsusing the appropriate tools. Photo by Robert Weldon.

Figure 17. Using a sanding wheel on a flexible shaft-motor, the setter vertically tapers the outside of the prongsholding the peridots (left). Bearings are then meticulously cut in each prong slightly above the upper gallerywire where the peridot will finally be seated (center), and the peridot is carefully positioned in the prong bear-ings (right). Photos by Robert Weldon.

pushed, one at a time, over the corners of thecrown. A jeweler’s saw is used to cut the prong tothe correct length (figure 18). Great care is taken tokeep the saw blade from touching the peridot, asthis would damage it. Last, the prongs are filed andpolished.

The primary goal was to set the peridots as lowas possible without letting the culets extend belowthe bottom gallery. After setting, they were per-fectly even and at the same height in each multi-stone piece.

Making the Ring. Although the above procedurewas applied for the necklace, earrings, and bracelet,a somewhat different process was used for the ring.This mounting started with a model that was pre-cisely hand-carved from a special wax used exclu-sively for items with intricate detail. The masterwax model was then cast in platinum and the plat-inum perfected by filing and polishing. To createthe sharpest and most precise details, which are not

possible with lost wax casting, the ring was com-pleted by hand fabricating the remaining compo-nents. Sheet and wire platinum were used to createthe upper and lower galleries and the four prongsthat would encase the peridot. The upper portion ofthe inside ring shank was then carefully crafted (fig-ure 19). After the components were soldered, theperidot and all 24 specially cut diamonds were fittedprior to pre-finishing, polishing, and then setting.

CONCLUDING THOUGHTSDuring the past 30 years, the gem and jewelryindustries have been blessed with a plethora of newgem deposits around the world, yielding extraordi-nary qualities and quantities of a wide variety ofgemstones. The discovery in the early 1990s of theSapat Valley peridot deposit is an exceptional exam-ple. The consistent availability of large, fine piecesof rough from Pakistan has had a significant impacton the jeweler’s ability to create beautiful designs

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Figure 18. The setter uses a prong-pusher to bend the prongs one at a time over the crown at each corner (upperleft). The prongs are then carefully shortened using a jeweler’s saw (lower left and right). Photos by Robert Weldon.

with important stones. The added benefit of anexpert preformer and faceter, as well as the talenteddesigners and craftspeople at Van Cleef & Arpels,enabled the creation of the matched necklace,

bracelet, ring, and earring suite described in thisarticle. If the gem dealer, cutter, and jeweler areinnovative and look for such opportunities, extraor-dinary jewelry can be produced.

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REFERENCESBoehm E. (2002). Portable instruments and tips on practical

gemology in the field. Gems & Gemology, Vol. 38, No. 1, pp.14–27.

Caspi A. (1997) Modern diamond cutting and polishing. Gems &Gemology, Vol. 33, No. 2, pp. 102–121.

Epstein D.S. (1988) Amethyst mining in Brazil. Gems &Gemology, Vol. 24, No. 4, pp. 214–228.

Federman D. (1992) Gem profile: Arizona peridot: Desert green.Modern Jeweler, Vol. 90, No. 5, pp. 39–40.

Federman D. (1995) Gem profile: Pakistan peridot. ModernJeweler, Vol. 94, No. 8, p. 14.

Frazier S., Frazier A. (1997) The perils of peridot pursuit. LapidaryJournal, Vol. 50, No. 12, pp. 18–23.

Hammer V.M.F. (2004) The many shades of Pakistan’s greengemstones. In ExtraLapis English No. 6: Pakistan—Minerals,Mountains & Majesty, Lapis International, LLC, pp. 64–71.

Jan M.Q., Khan M.A. (1996) Petrology of gem peridot from Sapatmafic-ultramafic complex, Kohistan, NW Himalaya. Geo-logical Bulletin, University of Peshawar, Vol. 29, pp. 17–26.

Kausar A.B., Khan T. (1996) Peridot mineralization in the Sapatultramafic sequence, Naran-Kohistan, Pakistan. Geologica,Vol. 2, pp. 69–75.

Koivula J.I., Kammerling R.C., Fritsch E., Eds. (1994a) Gem

News: Peridot from Pakistan. Gems & Gemology, Vol. 30,No. 3, p. 196.

Koivula J.I., Kammerling R.C., Fritsch E., Eds. (1994b) GemNews: More on peridot from Pakistan. Gems & Gemology,Vol. 30, No. 4, pp. 271–280.

Milisenda C.C, Bank H., Henn A. (1995) Peridot aus Pakistan.Zeitschrift der Deutschen Gemmologischen Gesellschaft,Vol. 44, No. 2/3, pp. 33–42.

Peretti A., Gübelin E.J. (1996) New inclusions in Pakistani peri-dot: Vonsenite-Ludwigite needles. Jewel Siam, Vol. 6, No. 6,pp. 68–69.

Revere A. (2001) The Art of Jewelry Making: Classic & OriginalDesigns. Sterling/Chapelle, New York, 144 pp.

Sevdermish M., Mashiah A. (1996) The Dealer’s Book of Gems andDiamonds, Vols. I and II. Kal Printing House, Israel, 1004 pp.

Sinkankas J. (1984) Gem Cutting: A Lapidary’s Manual, 3rd ed.Van Nostrand Reinhold Co., New York, 365 pp.

Suwa Y. (2001) Gemstones: Quality and Value, Volume 3—Jewelry (English edition). Sekai Bunka Publishing Inc., Tokyo,144 pp.

Untracht O. (1982) Jewelry Concepts and Technology.Doubleday Books, New York, 864 pp.

Watermeyer B. (1991) Diamond Cutting, 4th ed. Publ. by theauthor, Johannesburg, South Africa, 405 pp.

ABOUT THE AUTHORMr. Kane is a noted research gemologist and president of FineGems International, Helena, Montana ([email protected]).

ACKNOWLEDGMENTS: The author thanks the staff of VanCleef & Arpels (in Paris and New York) for their extraordinary

professionalism and kind cooperation. He also thanks Markand Lainie Mann for very useful information regarding themanufacture of jewelry, and Erica and Harold Van Pelt, JeffScovil, and Robert Weldon for their exceptional photographs.The author holds a shared copyright with the photographersand GIA on all the photographs in this article.

Figure 19. The maincomponent of the ringwas lost wax cast inplatinum. The settingfor the peridot (com-prising the upper andlower galleries, andfour prongs) washand-fabricated fromplatinum sheet andwire. The upperinside-shank sectionwas carefully fit tothe ring (inset), beforesoldering and trim-ming. Photo byRobert Weldon.

HPHT-GROWN SYNTHETIC DIAMOND CHART GEMS & GEMOLOGY WINTER 2004 303

lmost a decade ago, Shigley et al. (1995) pub-lished a comprehensive chart to illustratethe distinctive characteristics of yellow, col-

orless, and blue natural and synthetic diamonds. Theaccompanying article reviewed synthetic diamondproduction at the time, and discussed how the infor-mation presented on the chart was acquired andorganized. It also included a box that provided a“practical guide for separating natural from synthet-ic diamonds.” The chart was distributed to all Gems& Gemology subscribers, and a laminated versionwas subsequently made available for purchase.

Since that time, and especially within the pastseveral years, the situation of synthetic diamonds inthe jewelry marketplace has become more compli-cated. Lab-created colored diamonds are now beingproduced in several countries (including Russia, theUkraine, Japan, the U.S., and perhaps China andelsewhere), although the quantities continue to bevery limited. And today they are being sold specifi-cally for jewelry applications (figure 1), with adver-tisements for synthetic diamonds seen occasionallyin trade publications and other industry media.Recent inquiries to three distributors in the U.S.—Chatham Created Gems of San Francisco, Cali-

fornia; Gemesis Corp. of Sarasota, Florida; andLucent Diamonds Inc. of Lakewood, Colorado—indicate that their combined production of crystalsis on the order of 1,000 carats per month (mainly yel-low colors), a quantity that does not meet their cus-tomer demand.

The synthetic diamonds currently in the gemmarket are grown at high pressure and high temper-ature (HPHT) conditions by the temperature-gradi-ent technique using several kinds of high-pressureequipment (belt, tetrahedral, cubic, and octahedralpresses as well as BARS apparatuses), and one ormore transition metals (such as Ni, Co, and Fe) as aflux solvent/catalyst. Typical growth temperaturesare 1350–1600°C. Some lab-grown diamonds arebeing subjected to post-growth treatment processes(such as irradiation or annealing, or both) to changetheir colors (and, in some cases, other gemologicalproperties such as UV fluorescence). Thus, thegemologist is now confronted with the need to rec-

A

AN UPDATED CHART ON THECHARACTERISTICS OF HPHT-GROWN

SYNTHETIC DIAMONDS

James E. Shigley, Christopher M. Breeding, and Andy Hsi-Tien Shen

See end of article for About the Authors and Acknowledgments.GEMS & GEMOLOGY, Vol. 40, No. 4, pp. 303–313.© 2004 Gemological Institute of America

A new chart, supplementing the one published in the Winter 1995 issue of Gems & Gemology,summarizes the features of both as-grown (“non-modified”) and treated (“modified”) syntheticdiamonds currently in the gem market (that is, those grown by the high pressure/high temperaturetechnique). It includes photographs of visual features, information about visible-range absorptionspectra, and illustrations of growth-structure patterns as revealed by ultraviolet fluorescence imag-ing. The chart is designed to help gemologists recognize the greater variety of laboratory-createddiamonds that might be encountered today.

ognize faceted synthetic diamonds with colors thatare not only “as-grown” (yellow to yellow-brown tobrown, blue, green, and colorless), but also resultfrom post-growth treatment processes (yellow, yel-low-brown, brown, pink, red, purple, green, or blue-green), as described in Shigley et al. (2004).

While the information presented in the 1995chart remains valid, the contents of the updatedchart reflect the wider variety of HPHT-grown syn-thetic diamonds now in the marketplace1. However,this new chart is not a comprehensive guide to theidentification of as-grown and treated synthetic dia-monds; rather, it provides an overview of the com-mon characteristics of these materials, which canbe helpful in separating them from their naturalcounterparts.

Recently, synthetic diamonds suitable for jewel-ry use have also been produced in small numbers athigh temperatures but low pressures by the chemi-cal vapor deposition (CVD) process. This material,which is not yet commercially available for jewelrypurposes, has very different gemological propertiesfrom HPHT-grown samples and, therefore, is notincluded in this new chart. For further informationon CVD-grown material, see Wang et al. (2003) andMartineau et al. (2004).

CONTENTS OF THE NEW CHARTThe new chart is organized differently from the onepublished in 1995 (figure 2). Given the greateramount of information and broader variety of mate-rial available, the present chart focuses entirely onsynthetic diamonds and does not include entries fornatural diamonds. (The reader is directed to the ref-erences cited in Shigley et al., 1995—and informa-tion provided on that chart—for information on nat-ural as well as early synthetic diamonds. Also, dur-ing the past decade, several books and articles havedescribed many of the features of both natural andlab-created diamonds; these are listed in theAdditional Reading section at the end of this article.)

Regardless of their color, synthetic diamondsgrown by the HPHT technique from a moltenmetal flux have some common characteristics as aresult of their growth conditions. These includetheir cuboctahedral crystal shape (figure 3), growthfeatures (such as surface markings, color zoning,and graining), and metallic inclusions. Repre-sentative photos and photomicrographs illustratingthese three types of characteristics are groupedtogether across the upper portion of the new chartas a way to emphasize their common occurrence inHPHT-grown synthetic diamonds from all currentmanufacturers.

The lower portion of the chart is divided intotwo sections—one for information on synthetic dia-monds with as-grown (or “non-modified”) colors,and the other for those with treated (or “modified”)colors (figure 4). For the latter, the entries are divid-

304 HPHT-GROWN SYNTHETIC DIAMOND CHART GEMS & GEMOLOGY WINTER 2004

Figure 1. HPHT-grownSynthetic diamonds arenow available in the gemand jewelry market-place, as is evident fromthis attractive 1.00–1.25ct synthetic yellow dia-mond jewelry providedby Gemesis Corp. (thecolorless diamonds arenatural) and the (eachunder 1 ct) loose synthet-ic diamonds from Lucent Diamonds andChatham CreatedGems. Composite photo:jewelry images courtesyof Gemesis Corp.; loosediamond photos byHarold & Erica Van Pelt.

1Reports in the scientific literature indicate that as-grown synthetic dia-monds with a green color can also be produced when growth occursfrom a nickel solvent-catalyst along with a component in the flux thatactively combines with nitrogen (i.e., a nitrogen “getter”; see Chrenkoand Strong, 1975; Kanda, 1999). To the best of our knowledge, thiskind of synthetic diamond is not presently available in the market.

ed into the following four categories: (1) HPHTannealing, (2 and 3) irradiation plus annealing attwo different temperatures, and (4) irradiation only.Organizing information in this way is not meant toimply that the distinction of untreated and treatedcolors in synthetic diamonds is important. Rather,it is designed to help the gemologist who must testan unknown sample with a color that might not atfirst be considered typical of synthetic diamonds. Inaddition, in some cases—such as yellow or green—the color may be either as-grown or treated.

In this lower portion of the chart, the entries arepresented in a column format by color and diamondtype (a grouping of diamonds into one of several cat-egories based on their physical and spectral proper-ties; see, e.g., Fritsch and Scarratt, 1992; Wilks andWilks, 1994, pp. 62–82). Presenting information inthis way provides a basis for better understandingthe properties of the samples in each category. Thevisual features summarized in these two sectionsare supplemented by representative visible-rangeabsorption spectra, as well as by ultraviolet fluores-cence images of growth structure obtained with theDiamond Trading Company (DTC) DiamondViewinstrument (Welbourn et al., 1996). Such data areincreasingly important to confirm the identity ofsome synthetic diamonds. Information obtained bynondestructive chemical analyses for transitionmetals (such as Ni and Fe), as well as by other spec-troscopic (infrared and photoluminescence),cathodoluminescence, and analytical techniquesavailable in the larger gemological laboratories, mayalso be useful for synthetic diamond recognition.

The information presented in the chart is basedon data collected at GIA over the past 25 years onapproximately 500 synthetic diamonds from allknown sources of production. The photos and pho-tomicrographs were selected to illustrate those visu-al features of lab-grown diamonds useful for identifi-cation purposes.

We do not indicate the manufacturer or distributorof the synthetic diamonds illustrated on the chart fortwo reasons. First, we know that once a synthetic dia-mond is sold in the trade, such information may nolonger be available (unless a distinctive marking visi-ble with magnification is placed on the girdle surface

Figure 3. HPHT-grown synthetic diamond crystalsare usually cuboctahedral in shape, as illustratedby these colored synthetic diamonds fromChatham Created Gems, which weigh between0.44 and 1.74 ct. Photo by Maha Tannous.

Figure 2. The chart pub-lished by Shigley et al. in

1995 included informa-tion on natural diamonds

as well as on the kindsof HPHT-grown synthetic

diamonds available atthat time.

HPHT-GROWN SYNTHETIC DIAMOND CHART GEMS & GEMOLOGY WINTER 2004 305

306 HPHT-GROWN SYNTHETIC DIAMOND CHART GEMS & GEMOLOGY WINTER 2004

by the manufacturer [see below]). Second, since eachcommercial source uses the same basic HPHT growthtechnique (although, possibly, with different equip-ment and procedures), all synthetic diamonds createdwith this method have many similar gemologicalproperties that do not necessarily allow for a differenti-ation of the products of various manufacturers.

The visible absorption spectra included in thechart (collected at liquid nitrogen temperature) illus-trate the general pattern of spectral features for eachkind of synthetic diamond. These features corre-spond in some instances to those that might be seenusing a desk-model spectroscope, and they give riseto the colors of the synthetic diamonds. Specificsharp absorption bands shown on the chart may ormay not be present in the spectrum of a particularsample for several reasons (i.e., the type of sample,the method of growth, the flux metals used duringgrowth, and the manufacturer, as well as the type ofspectrometer and the data collection conditions).Conversely, other synthetic diamonds may exhibitadditional spectral features not shown here. Theinterested reader is referred to the more completedescriptions of diamond spectra that have been pub-lished (see Wilks and Wilks, 1994; Collins, 2000,2001; and Zaitsev, 2001).

The organization of information in the chartrequires some clarification. First, in both naturaland synthetic diamonds there are variations innitrogen and boron contents, and in the degree ofnitrogen atom aggregation. Both these factors definediamond type (i.e., type I, type II). Thus, the varioustype designations actually fall along a continuum,rather than being completely distinct categories asimplied by the columnar organization of the lowerportion of the chart. Also, with regard to “non-mod-ified” (or as-grown) versus “modified” (or treated)colors, in reality, HPHT growth conditions andHPHT treatment conditions may in some instances(e.g., “yellow/brown,” as-grown and as treated withHPHT annealing) be very similar. Consequently,

one might see a corresponding similarity in theproperties of some synthetic diamonds of the samecolor listed on the lower left and lower right portionsof the chart. Last, the information given represents aconsensus of observations on the synthetic dia-monds that GIA has documented to date. In somecases (for example, irradiated green synthetic dia-monds), only a limited number of samples wereavailable to us for examination. As we study moresamples in specific color groups, certain informationmay need to be expanded or modified.

It should be emphasized that we have notobserved all the features shown on the chart inevery synthetic diamond we have examined.Rather, all synthetic diamonds we have document-ed exhibited one or more of the distinctive proper-ties listed here. This reinforces the importance ofbasing identification conclusions on as wide a vari-ety of properties as possible rather than on just oneor two features.

SYNTHETIC DIAMOND IDENTIFICATIONThe ability to recognize a synthetic diamond firstrequires an understanding of the kinds of as-grownand treated materials that are now available. Overallproduction of gem-quality crystals remains very lim-ited—to the best of our knowledge, perhaps 12,000carats per year. Almost all are colored crystals up toabout 2 ct (with faceted material up to about 1 ct). Itis now possible to produce synthetic diamonds thatcontain little nitrogen and, as a result, might not bestrongly colored. However, growth of type IIa color-less material continues to be difficult to achieve inthe laboratory, and we do not believe it is availablein significant quantities for jewelry purposes. GIAhas documented only a few faceted colorless syn-thetic diamonds obtained from the gem trade duringthe past decade (see, e.g., Rockwell, 2004).

In recent years, improvements in growth technol-ogy and techniques have resulted in colored synthet-

Figure 4. Synthetic diamonds currently sold for jewelry purposes display a range of as-grown and treated colors. Theas-grown yellow crystal (2.43 ct) and three yellow faceted samples (0.28–0.84 ct) shown on the left represent the mostcommon kind of synthetic diamond produced today. The colors of the green-to-blue faceted samples (0.20–0.40 ct)shown in the center also were produced during growth. In contrast, the pink-to-pinkish purple colors of the facetedsamples (0.16–0.50 ct) shown on the right result from post-growth treatment processes. Photos by Maha Tannous.

ic diamond crystals that are larger, have lower impu-rity contents, and are better quality. This finer quali-ty is evident in the presence of few if any metallicinclusions and flaws, as well as less obvious colorzoning in some cases. Nonetheless, lab-created dia-monds can still be recognized by a variety of meth-ods. Numerous articles (including the present one)and shorter reports describing these methods, whichwere published in Gems & Gemology over the past30 years, have been collected together for a specialvolume that will be made available by GIA in early2005 (Shigley, in preparation). By reviewing thisinformation, as well as what is presented on thischart, the gemologist will be better prepared to rec-ognize this material. The key identifying features ofsynthetic diamonds are summarized below.

Crystal Shape and Growth Structure. Natural dia-mond crystals typically exhibit an octahedral form,with many variations due to growth and/or dissolu-tion (Orlov, 1977, pp. 59–106; Wilks and Wilks,1994, pp. 108–126). In contrast, synthetic diamondsusually have a cuboctahedral form (again, see figure3), which overlies a geometric arrangement of octa-hedral, cubic, and dodecahedral internal growth sec-tors. In a vertical orientation, these sectors radiateupwards and outwards from the seed location at thebase of the crystal (see Welbourn et al., 1996, p. 162,

figure 5). Diamond crystallization is accompaniedby the incorporation of different amounts of impuri-ties in these sectors—thus leading to a segregationof these impurities between sectors. Differentialincorporation of impurities gives rise to the distinc-tive zoning of color, graining, and luminescenceseen in many synthetic (as compared to natural) dia-monds. When present, boundaries between adjacentcolor zones are usually sharp and planar (figure 5);they also may intersect to form angular patterns.Adjacent zones may be distinguished merely bylighter and darker appearances of the same color, orby zones of very different color. For example, cer-tain lab-grown green samples now being sold byChatham Created Gems exhibit both yellow andblue growth sectors when examined with a micro-scope (see Shigley et al., 2004). Post-growth colortreatment processes do not obscure or remove thesedistinctive visual features, although it may be possi-ble to lessen the visibility of the color zoning duringgrowth (especially if one growth sector predomi-nates within the crystal, while other sectors of dif-fering color are smaller and thus less obvious).

Careful examination using a gemological micro-scope and different lighting techniques is the bestway to see this growth sector–related color zoningin lab-grown diamonds. Immersion of the sample ina liquid (even water) for better observation is also

Figure 5. Colored syn-thetic diamonds oftenexhibit distinct colorzoning due to differencesin impurity contentsbetween internal growthsectors. These fourexamples (0.17–0.68 ct)illustrate how thesezoning patterns oftenappear as seen throughthe crown and pavilionfacets. Immersing thematerial in a liquid(here, water) can aid inthe observation of thesepatterns. Photos by J. E.Shigley; magnified 20¥.

HPHT-GROWN SYNTHETIC DIAMOND CHART GEMS & GEMOLOGY WINTER 2004 307

helpful. Such zoning should be evident as wellwhen the sample is examined with a standard UVfluorescence unit or the DTC DiamondView.Depending on the viewing orientation, the zoningcan display two-, three-, or four-fold patterns relatedto the diamond’s cubic crystal symmetry. In mostcases, the table facet of a polished sample is orient-ed approximately parallel to the cube face of theoriginal crystal for maximum weight retention dur-ing faceting. Therefore, it is often best to look forany four-fold color or fluorescence zoning pattern byobserving through the table or crown facets—or,alternatively, nearly parallel to the girdle facets—while rotating the sample. The key is to examine asample in several orientations to look for changes incolor or fluorescence separated by distinct planarboundaries (figure 6).

Inclusions, Graining, and “Strain” Patterns. Unlessthey are prevented from forming during growth, orare physically removed during faceting, metallicinclusions are a common feature in many polishedsynthetic diamonds. They may be rounded, elon-gate, or irregular in shape, and will appear opaque intransmitted light and dark gray-to-black (sometimeswith a metallic luster) in reflected light. They mayoccur singly or in groups, and can vary in size. In

some cases, their large size makes them virtuallyeye-visible (figure 7); whereas in other instances,they are so tiny as to be described as “pinpoint”inclusions, which are often seen in diffuse, cloud-like arrangements (figure 8). (Note that althoughsome of these pinpoint inclusions may be metallic,others may represent different phases formed duringsynthesis.) Some of these inclusions may even be

308 HPHT-GROWN SYNTHETIC DIAMOND CHART GEMS & GEMOLOGY WINTER 2004

Figure 7. Metallic inclusions, such as those shown inthis 0.26 ct pink sample, are a distinctive visual fea-ture of many HPHT-grown synthetic diamonds.Photomicrograph by Shane McClure; magnified 25¥.

Figure 6. These four DTCDiamondView images of a0.43 ct blue synthetic dia-mond illustrate the chang-ing pattern of fluorescentand nonfluorescent growthsectors seen as the sample isrotated. The face-up view(A) shows the four-fold,cross-shaped fluorescencepattern typical of HPHT-grown synthetic diamonds,although in this orientationthe sample displays a slight-ly complicated arrangementof growth sectors. As thesample is rotated towardthe pavilion (B and C), thegrowth sector arrangementbecomes more regular instructure. Fine growth stria-tions (resulting from slightvariations in impurity con-tents during growth) are vis-ible within the yellowishfluorescing sectors in thepavilion views (C and D).Images by Andy Shen.

AA B

C D

invisible with the magnification of a standard gemo-logical microscope. Because the flux inclusionsoften contain iron, they can result in the syntheticdiamond being attracted to a magnet.

Natural diamonds may display linear, cross-hatched, or irregular (“mosaic”) internal grainingpatterns (Kane, 1980). In synthetic diamonds, inter-nal graining in linear or intersecting geometric pat-terns appears to be the result of slight differences inrefractive index between adjacent growth sectors, orbetween successive parallel “layers” of materialbeneath the crystal faces. It is best seen along theboundaries between sectors, or in planes that paral-lel the outer shape of the original crystal. Since thecuboctahedral crystals are often faceted in square orrectangular shapes for weight retention, one goodplace to check for graining in faceted samples isnear the corners of the table facet (and adjacentcrown facets) with magnification (a fiber-optic illu-minator can be quite helpful).

Most natural diamonds exhibit anomalous dou-ble refraction (ADR) in banded, cross-hatched, ormottled patterns with bright interference colors(when observed through crossed polarizing filters;see Orlov, 1977, pp. 109–116). In comparison, ourexperience is that synthetic diamonds display muchweaker, cross-like “strain” patterns with subduedinterference colors (black or gray).

Luminescence. Given the wide variety of syntheticdiamonds now available, their reactions to long-and short-wave UV radiation can differ greatly interms of fluorescence intensity, color, distributionpattern, and phosphorescence. While it has beenwidely reported that most lab-grown samples dis-play stronger fluorescence to short-wave UV than tolong-wave, the opposite reaction has also beenobserved (as well as the same intensity reaction toboth UV lamps), and some samples are inert to bothUV excitations. To check for weak UV fluorescencereactions, it is best to observe the sample while in adarkened room, after the eyes have had time toadjust to low light levels. In more recent years, wehave noticed an increasing number of synthetic dia-monds that display only weak UV fluorescence, orno fluorescence reaction at all.

As mentioned, fluorescence colors can also vary,but typically they range from green to blue to yellowto orange or orange-red. More importantly, however,this fluorescence is often unevenly distributed, sothat some portions of the sample fluoresce whereasothers do not (or they fluoresce with different colors;

see figure 9). This uneven distribution is again areflection of the arrangement of internal growth sec-tors with their differing impurity contents, so thereis a direct spatial relationship between color, grain-ing, and UV fluorescence patterns. In the most obvi-ous cases, this uneven fluorescence is seen as asquare and/or cross-shaped geometric pattern. Again,the orientation of the faceted shape with respect tothe original crystal will influence how color, grain-ing, and fluorescence patterns appear, so it is impor-tant to examine a sample in several orientations.

Similar fluorescence patterns in synthetic dia-monds can be observed using the cathodolumines-cence technique (where the sample is exposed to abeam of electrons while being held in a vacuumchamber). The DTC DiamondView, where fluores-cence reactions are excited by exposure of the sam-ple to UV radiation with wavelengths shorter than230 nm, also provides an excellent tool for viewingsurface-related fluorescence and phosphorescencepatterns in a sample at different orientations (seeWelbourn et al., 1996, and figure 6).

Colorless synthetic diamonds, and any coloredsamples that contain boron as an impurity, frequent-ly display persistent greenish or yellowish phospho-rescence (for up to 60 seconds or longer) when theUV lamp is turned off (see Shigley et al., 1997). Sincephosphorescence is a phenomenon that decreases inintensity over time, it is again important to checkfor this kind of luminescence by viewing the sam-ples in a darkened room. A good technique is toclose one’s eyes, and then open them at the sametime the UV lamp is turned off. Blue (and some near-colorless) synthetic samples containing boron willexhibit electrical conductivity and, interestingly,

Figure 8. In some cases, synthetic diamonds display“clouds” of pinpoint inclusions of uncertain identity.Since some natural diamonds also exhibit similarcloud-like arrangements, these pinpoint inclusions donot provide a reliable means of separation. Photo-micrograph by Shane McClure; magnified 30¥.

HPHT-GROWN SYNTHETIC DIAMOND CHART GEMS & GEMOLOGY WINTER 2004 309

will often display visible electroluminescence in theform of momentary tiny flashes of white to bluishwhite light when the samples are touched by theconductometer probe.

Chemical and Spectroscopic Analysis. Non-destructive methods of chemical analysis provideanother rapid means of identifying synthetic dia-monds by detecting flux metals (Ni, Co, and Fe) thatare used in diamond growth. Particularly useful inrecognizing lab-created diamonds, especially thosethat lack distinctive visual features, are several spec-troscopy techniques that are found today in manygemological laboratories. Because diamond is rela-tively transparent from the infrared through the visi-ble and ultraviolet regions of the electromagneticspectrum, numerous absorption and emission fea-tures can be detected by these techniques (Zaitsev,2001, lists the spectral features individually alongwith a brief description of what is known aboutthem). Specific bands caused by the presence of tran-sition metals are valuable for detecting either as-

grown or treated synthetic diamonds by visible spec-troscopy (for example, those at 494, 658, and 732 nm,as well as several others, which are all due to nickel;see again Zaitsev, 2001). Caution must be exercised,however, as we now know that some natural dia-monds contain small amounts of nickel (see, e.g.,Chalain, 2003; Lang et al., 2004; Hainschwang andNotari, 2004). Photoluminescence (PL) spectroscopyis increasingly important for gem laboratories, sincemany of the optical centers in diamond have associ-ated sharp PL bands that are useful for identificationpurposes. The interested reader is referred to articlescited in the reference list for examples of the applica-tion of these and other spectroscopy methods to dia-mond characterization (see, e.g., Lawson et al., 1996;Collins, 2000, 2001; Zaitsev, 2000, 2001; Yelisseyevet al., 2002). Additional analytical techniques fordetecting synthetic diamonds may become useful inthe future.

Other features. As an aid to identification and disclo-sure, some manufacturers are inscribing a distinctive

310 HPHT-GROWN SYNTHETIC DIAMOND CHART GEMS & GEMOLOGY WINTER 2004

Figure 9. These four syn-thetic diamonds exhibittypical zoned fluorescencereactions when exposed tolong-wave (top left, treated)and short-wave (remainingthree images, as grown)ultraviolet radiation. Inour experience, the fluores-cence is usually stronger toshort-wave UV than long-wave for as-grown syntheticdiamonds, whereas it canbe of equal intensity orstronger to long-wave UVfor treated synthetic dia-monds. In each instanceshown here, certain growthsectors are fluorescingwhile others are not,resulting in a four-foldcross-shaped pattern. It isimportant to examine thesample both face-up andface-down, since the fluo-rescence may be emittedfrom just a localized area.Photos by Shane Elen andJohn I. Koivula.

mark or other information on the girdle facets of theirpolished synthetic diamonds; such a mark is easilyvisible with 10¥ magnification. In addition, certaingem-testing laboratories have agreed to issue gradingreports on synthetic diamonds along with a clearlyworded statement that they are laboratory grown.

CONCLUSIONThe chart accompanying this article presents char-acteristics of both as-grown and treated syntheticdiamonds produced under HPHT conditions using ametal or metal-alloy flux. While visual featuressuch as color zoning and metallic inclusions remainvaluable identification criteria, efforts to producebetter-quality synthetic diamonds have resulted insuch features becoming less evident (or even absent)in some recently grown material. Therefore, therecording of visible-range absorption and other spec-tra, and the observation of UV fluorescence pat-terns, have become increasingly important for syn-thetic diamond identification.

Particularly problematic for jewelers and gemol-ogists are small stones. It is easier, faster, and cheap-er to grow synthetic diamonds in the form of melee,but the small size means that the visual identifyingfeatures usually are more difficult to see with themicroscope, and the large numbers make individualtesting of whole parcels impractical. The best solu-tion for parcels of melee is to submit representativesamples to a gem-testing laboratory where thematerial can be fully characterized.

As one looks toward the future, continuedresearch on diamond growth—and the possibilitythat more and larger synthetic diamonds will be pro-duced—could pose further challenges for the jewelryindustry. Although not yet a commercial process,

the chemical vapor deposition (CVD) techniquecould yield larger synthetic diamonds that mightlack, for example, growth sector–related color andUV fluorescence zoning patterns (in addition, theywould not contain metallic inclusions). The absenceof these features would make identification in astandard gemological laboratory more difficult, espe-cially in colorless material, although the evidencefrom samples examined to date indicates that suchmaterial is clearly identifiable with advanced tech-niques such as the DTC DiamondView.

Scientific efforts are also underway to grow dia-monds using flux materials other than transitionmetals (such as carbonate or silicate compounds;see, e.g., Arima et al., 2002: Litvin et al., 2002; Okadaet al., 2002; Pal’yanov et al., 2002; Yamaoka et al.,2002). So far, only microscopic diamond crystalshave been produced in this way. However, crystal-lization from these fluxes under HPHT conditionsmay eventually yield larger synthetic diamonds thatlack some of the diagnostic features (such as metal-lic inclusions) seen in the HPHT material currentlybeing marketed. Again, there is no evidence to datethat such a growth process has been devised that canyield a synthetic diamond crystal of sufficient sizeand quality to make it suitable for faceting.

Improvements in diamond growth capabilities arean inevitable result of the ongoing scientific interestin diamond as a desirable high-technology material.As new kinds of synthetic diamonds are produced,gemological research must continue to develop prac-tical means of identifying them using both standardand more sophisticated techniques. The goal is tocreate detection methods that can be applied to allsynthetic diamonds—even those of melee size,where the rapid screening of large numbers of dia-monds of unknown origin will be important.

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Chalain J-P. (2003) Gem News International: A natural yellow dia-mond with nickel-related optical centers. Gems & Gemology,Vol. 39, No. 4, pp. 325–326.

Chrenko R.M., Strong H.M. (1975) Physical Properties ofDiamond. Report No. 75CRDO89, General Electric Co.,

ABOUT THE AUTHORS

Dr. Shigley is director of research, and Dr. Breeding and Dr.Shen are research scientists, in the GIA Gem Laboratory,Carlsbad, California.

Acknowledgments: The following individuals at GIA contributed tothe collection of the information and photographic images used in

this chart: Dino DeGhionno, Thomas Gelb, Scott Guhin, ShaneElen, Matthew Hall, John King, John Koivula, Dr. Taijin Lu, ShaneMcClure, Sam Muhlmeister, Elizabeth Quinn, Dr. Ilene Reinitz,Christopher Smith, Maha Tannous, and Dr. Wuyi Wang. We thankChatham Created Gems of San Francisco, California, the GemesisCorporation of Sarasota, Florida, and Lucent Diamonds Inc. ofLakewood, Colorado, for their loans of recent samples for study.

HPHT-GROWN SYNTHETIC DIAMOND CHART GEMS & GEMOLOGY WINTER 2004 311

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This article describes the first application oflaser-induced breakdown spectroscopy (LIBS) togemology. So far, the detection of Be-diffusedsapphire and ruby has been based on LA-ICP-MS or SIMS, neither of which is readily avail-able to most laboratories. In this study, we useLIBS to detect beryllium in corundum at verylow concentrations (down to ~2 ppm). Thistechnique is a reliable tool for identifying Bediffusion–treated sapphires, and is affordable formost commercial gemological laboratories. Aswith other laser-based techniques, LIBS maycause slight damage to a gemstone, but this canbe minimized by choosing appropriate instru-ment parameters.

apphires treated by beryllium diffusion enteredthe gem trade in mid-2001, and the first labo-ratory alert on this treatment was issued by

the American Gem Trade Association in New Yorkon January 8, 2002 (Scarratt, 2002). This treatmentmodifies various colors of corundum into stones ofmore attractive hues, usually yellow or orange toorangy red (figure 1). Some of these colors are ratherrare in untreated or traditionally heated corundum,so the stones may be very valuable, especially theorangy pink variety (“padparadscha”). Several stud-ies of Be-diffused corundum have revealed that thepresence of low concentrations of beryllium (i.e.,~5–10 ppm) in the corundum lattice may result in adistinct yellow-to-orange coloration (Hänni andPettke, 2002; Peretti and Günther, 2002; Emmett et

al., 2003; Pisutha-Arnoud et al., 2004). In contrast,untreated or traditionally heated sapphires of simi-lar color contain no Be or have only minute traces(i.e., parts-per-billion [ppb] levels) of this light ele-ment (Emmett et al., 2003; D. Günther, pers.comm., 2004).

Unfortunately, the detection of Be-diffused sap-phires has proved difficult, because testing by tradi-tional nondestructive analytical methods (e.g., ener-gy-dispersive X-ray fluorescence [EDXRF]) cannotdetect light elements such as Be. Although someBe-diffused sapphires can be identified by a yellow-ish orange rim when observed in immersion (see,e.g., Hänni and Pettke, 2002; McClure et al., 2002;Peretti and Günther, 2002; Emmett et al., 2003),often no such diffusion feature is present. Untilnow, the reliable detection of Be diffusion has usual-ly required highly sophisticated methods, such aslaser ablation–inductively coupled plasma–massspectrometry (LA-ICP-MS) or secondary ion massspectrometry (SIMS). Both techniques are slightlydestructive, as they vaporize a minute quantity ofthe sample for analysis with a mass spectrometer(Guillong and Günther, 2001).

Since the two analytical techniques describedabove are quite expensive, time consuming, andonly rarely at the disposal of gemological laborato-ries, we investigated a more affordable technology.In July 2003, we began to evaluate the potential of

314 NOTES AND NEW TECHNIQUES GEMS & GEMOLOGY WINTER 2004

S

A NEW METHOD FOR DETECTINGBE DIFFUSION–TREATED SAPPHIRES:

LASER-INDUCED BREAKDOWNSPECTROSCOPY (LIBS)Michael S. Krzemnicki, Henry A. Hänni, and Roy A. Walters

See end of article for About the Authors and Acknowledgments.GEMS & GEMOLOGY, Vol. 40, No. 4, pp. 314–322.© 2004 Gemological Institute of America

NOTES & NEW TECHNIQUES

laser-induced breakdown spectroscopy (LIBS) forgemstone analysis. As in the other methods men-tioned above, LIBS analysis also is slightly destruc-tive, as a small portion of the sample is ablated by alaser. Our initial results revealed the potential ofLIBS to detect Be-diffused corundum (Hänni andKrzemnicki, 2004). In April 2004, SSEF became thefirst laboratory to install a LIBS instrument that wasspecially designed for gemstone analysis. Since July2004, SSEF has offered Be detection in corundum asa regular service to its clients. In this article, we pre-sent the first detailed results obtained by LIBS onberyllium-diffused corundum, as analyzed with theSSEF GemLIBS system (table 1).

LIBS BACKGROUNDLIBS can provide qualitative to semiquantitativechemical data. Initial studies on laser spark spec-troscopy (Brech and Cross, 1962; Allemand, 1972;Corney, 1977) were further developed in the early1980s, mainly by scientists at Los Alamos NationalLaboratory in New Mexico. Radziemski et al.(1983) showed the ability of LIBS to detect traceconcentrations of Be (in air) as low as 0.5 ppm.Recently, major improvements in laser and spec-trometer technology have dramatically expandedthe possibilities and applications of LIBS for mili-tary uses, environmental monitoring, process con-trol, and material analysis (Bogue, 2004); theseinclude remote in-situ testing of fine particulatematter (Carranza and Hahn, 2002) and real-timeanalysis of steel composition during production(Gruber et al., 2004). The use of LIBS in the gem

industry has so far been rather limited, and hasinvolved analyzing the composition of jewelrymetal alloys (e.g., García-Ayuso et al., 2002) as wellas Be-diffused corundum (Krzemnicki and Hänni,2004).

The principle behind LIBS is the interaction of alaser with a sample to produce an optical emissionspectrum that is specific to that sample. A pulsedlaser focused onto a sample (solid, liquid, or gas)vaporizes a small portion for analysis. The super-heated, ablated material is transformed into a plas-ma, a form of matter in which the original chemicalbonds of the substance are broken apart and theresulting atoms are converted into a mixture of neu-tral atoms, ions, and electrons. The atoms and ionswithin the expanding plasma lose some of theirenergy by emitting light, which produces a charac-teristic emission spectrum in the ultraviolet, visi-ble, and near-infrared spectral range. The spectrumis then recorded with a spectrometer. Due to com-plex plasma dynamics, LIBS does not yield quantita-tive data. By using reference standards of knowncomposition, it is sometimes possible to calibratethe instrument to generate semiquantitative data,such as for Be in a corundum matrix (Krzemnickiand Hänni, 2004).

MATERIALS AND METHODSIn this study, we present data on 21 well-character-ized faceted natural sapphires and rubies, as well asthree synthetic corundums (figures 2 and 3; table 2).Six of the natural corundums were Be-diffused (Be-1–Be-6). Fifteen of the natural samples were

Figure 1. The attractivecolors of the UmbaValley (Tanzania) sap-phires in this compositephoto were produced byBe diffusion. The loosestones range from 1.27 to7.91 ct, and the sapphiresin the 18K white goldjewelry are 3.19 ct (ringcenter stone) and 3.52 cttotal weight (leaf pen-dant). Photo by MyriamNaftule Whitney; cour-tesy of Nafco Gems,Scottsdale, Arizona.

NOTES AND NEW TECHNIQUES GEMS & GEMOLOGY WINTER 2004 315

not Be-diffused (NBe-1–NBe-15), but nine of themwere heated by traditional methods. The naturalsamples were compared to a flame-fusion synthet-ic orange sapphire (BeS-1) that was doped with aminute amount of Be (2–3 ppm measured by LA-ICP-MS) to investigate the detection limit of ourparticular LIBS configuration. In addition, a flame-fusion synthetic ruby (NBeS-1) and a flame-fusionsynthetic color-change sapphire (NBeS-2) were

analyzed to study possible peak interference bychromium and vanadium with the Be emissiondoublet at 313 nm in the LIBS spectra.

All samples were chemically analyzed byEDXRF spectrometry, using a Tracor Spectrace5000 instrument, to determine semiquantitativeconcentrations of Ti, V, Cr, Fe, and Ga. Additionalelements (such as Na, Mg, Si, Ca, Mn, Ni, Cu, andZn) were typically below the EDXRF detectionlimit. As EDXRF spectrometry is not capable ofanalyzing light elements such as Be, only by usingmethods such as LIBS, LA-ICP-MS, or SIMS is itpossible to detect them in corundum. We used LA-ICP-MS to obtain quantitative data on Be (and othertrace elements) in all six Be-treated samples (Be-1–Be-6), in three of the stones treated by traditionalheating (NBe-1, NBe-6, and NBe-14), and in the Be-doped synthetic sapphire (BeS-1), for comparisonwith the LIBS spectra. The LA-ICP-MS analyseswere obtained using a pulsed Excimer ArF laserwith a characteristic wavelength of 193 nm for sam-ple ablation, combined with special optics tohomogenize the energy distribution across the laserbeam (Günther et al., 1997; now commerciallyavailable as the GeoLas system). The ICP-MS was aquadrupole instrument from PerkinElmer, theELAN 6100. The size of the ablated laser pits wasabout 100 mm in diameter and a few tens ofmicrometers deep. In contrast to many other com-mercially available LA-ICP mass spectrometers,this instrument is characterized by a perfectly flatlaser beam geometry, which enables drilling of very

316 NOTES AND NEW TECHNIQUES GEMS & GEMOLOGY WINTER 2004

Figure 2. These are some of the corundum samplesthat were analyzed by LIBS for this study. The facetedstones on the left are Be-diffused sapphires (Be-1 toBe-4). On the bottom right are samples that have beenheated by traditional methods with no Be-diffusion(NBe-1, NBe-6, and NBe-14). In the background are asplit boule of orange flame-fusion synthetic sapphirethat was doped with Be (sample BeS-1) and a facetedflame-fusion synthetic ruby without Be (sampleNBeS-1). Photo by M. S. Krzemnicki, © SSEF.

Figure 3. These are the additional non-Be-diffused nat-ural corundum samples that were analyzed for this

study. From left to right, top row: NBe-9 (Umba,Tanzania), NBe-15 (Luc Yen, Vietnam), NBe-5 and

NBe-3 (Sri Lanka), NBe-10 (Tunduru, Tanzania); andbottom row: NBe-8 and NBe-7 (Tanzania), NBe-13

(Ilakaka, Madagascar), NBe-4 and NBe-2 (Sri Lanka),NBe-11 and NBe-12 (Tunduru, Tanzania). As expected,

the LIBS analyses for all of these samples revealed noevidence of beryllium. Photo by H. A. Hänni, © SSEF.

TABLE 1. Characteristics of the SSEF GemLIBS system.

Laser: Single-pulsed Nd:YAG laserPulse duration 7 nanosecondsWavelength 1064 nmEnergy 100 millijoulesFrequency 3 HzFocus lens 35 mm

Spectrometer: Ocean Optics LIBS2000+

Range 200–980 nm broadband spectrumQ-switch delay 2 microsecondsAnalysis Simultaneous, real-timeResolution 0.1 nm FWHM (full width at half maxium)

Sample chamberDimensions 17 ¥ 22 ¥ 14 cm (width ¥ height ¥ depth)Protection Laser safety plastic, 180° visibilityConditions Measured in airSample holder Manual x-y-z sample stage

precise flat round laser holes. More details aboutthis setup will be provided in an article on the appli-cation of LA-ICP-MS in gemology (M. S. Krzem-nicki et al., in preparation)

The SSEF GemLIBS system used for the LIBSanalyses consists of an Ocean Optics LIBS 2000+instrument that was modified for gemological pur-poses with an x-y-z sample holder for precise tar-geting (see table 1 and figures 4 and 5). The samplewas fixed to a glass plate with some Blu-Tack andpositioned under the laser. The system uses a sin-gle-pulse 1064 nm Nd:YAG laser (pulse duration of7 nanoseconds with an energy of 100 millijoules[mJ]) from BigSky Quantel. A series of overlappinghigh-resolution fiber-optic spectrometers enablesthe simultaneous recording of emission spectra inthe range 200–980 nm, in which the emission lines

of all elements are found. The peak resolution (fullwidth at half maximum [FWHM]) is 0.1 nm. Thus,it is possible to detect emission lines that are veryclose to one another.

Laser safety is an important consideration whenperforming LIBS analysis or other laser-based experi-ments (e.g., Raman and LA-ICP-MS). The laser ener-gy used for LIBS analysis is powerful, and reflectionfrom gemstone facets may cause damage to the reti-na of the eye. The system comes with a transparentlaser-protected sample chamber. LIBS analysesshould only be carried out while the sample cham-ber is completely closed.

In our study, numerous emission lines fromelements of the corundum matrix (Al, Cr, Fe, V,Ti) and the atmosphere (O, N) were encountered.In accordance with Radziemski et al. (1983), Be

TABLE 2. LIBS samples for this study on Be diffusion–treated corundum.a

Weight LA-ICP-MS LIBSSample Mineral Treatment (ct) Form Origin Be (ppm) Be detection

Be-1 Purple sapphire Be diffusion 0.63 Faceted East Africa 34–49 PositiveBe-2 Orange sapphire Be diffusion 1.26 Polished slab East Africa 5–21 PositiveBe-3 Orange sapphire Be diffusion 1.00 Faceted East Africa 8–11 PositiveBe-4 Orange sapphire Be diffusion 0.85 Faceted East Africa 8–10 PositiveBe-5 Orange sapphire Be diffusion 0.98 Faceted East Africa 4–10 PositiveBe-6 Yellow sapphire Be diffusion 0.97 Faceted Sri Lanka 9–11 Positive

BeS-1 Synthetic orange sapphireb Be diffusion 242.17 Split boule Flame fusion 2–3 Positive(very low)

NBeS-1 Synthetic ruby None 5.47 Faceted Flame fusion na NegativeNBeS-2 Synthetic V-corundum None 2.64 Faceted Flame fusion na Negative

NBe-1 Yellow sapphire Heated 1.51 Faceted Sri Lanka bdl NegativeNBe-2 Yellow sapphire Heated 2.57 Faceted Sri Lanka na NegativeNBe-3 Light yellow sapphire Heated 2.18 Faceted Sri Lanka na NegativeNBe-4 Orangy pink sapphirec None 0.73 Faceted Sri Lanka na NegativeNBe-5 Pink sapphire None 2.10 Faceted Sri Lanka na NegativeNBe-6 Sapphire Heated 1.22 Faceted Sri Lanka bdl NegativeNBe-7 Ruby None 0.60 Faceted Tanzania na NegativeNBe-8 Light purple sapphire None 0.88 Faceted Tanzania (Umba) na NegativeNBe-9 Slightly brownish None 1.53 Faceted Tanzania (Umba) na Negative

pinkish orange sapphireNBe-10 Pink sapphire Heated 1.10 Faceted Tanzania (Tunduru) na NegativeNBe-11 Pink sapphire Heated 1.27 Faceted Tanzania (Tunduru) na NegativeNBe-12 Light pink sapphire Heated 1.47 Faceted Tanzania (Tunduru) na NegativeNBe-13 Light pink sapphire Heated 2.15 Faceted Madagascar (Ilakaka) na NegativeNBe-14 Ruby Heated 1.05 Faceted Kenya bdl NegativeNBe-15 Ruby None 2.40 Polished Vietnam (Luc Yen) na Negative

fragment

a Abbreviations: bdl = below detection limit (0.3–0.8 ppm); na = not analyzed by LA-ICP-MS (only EDXRF), so Be was not quantified.b Analyses performed near the rim of the cleaved Be-doped synthetic orange sapphire.c Also referred to as the “padparadscha” variety of corundum.

NOTES AND NEW TECHNIQUES GEMS & GEMOLOGY WINTER 2004 317

318 NOTES AND NEW TECHNIQUES GEMS & GEMOLOGY WINTER 2004

detection was based on the presence of the first-order ionic Be II doublet at 313.042 and 313.107nm (NIST database). Using our LIBS system, this

doublet was not resolved but appeared as a singlepeak centered at 313.08 nm. A weaker Be emis-sion was found at 234.86 nm. However, this emis-sion was not used, since Fe from the corundummatrix may produce overlapping peaks.

Repeated testing revealed that about 20 lasershots per LIBS analysis resulted in a high signal-to-background ratio for the Be emission at 313nm. Additional laser pulses only slightlyincreased this ratio. The method was furtherimproved by focusing the laser slightly above thesurface of the sample. We found that the delayafter the laser pulse, which is when the character-istic optical emission of an element is analyzed, isalso an important factor. Immediately after thelaser pulse, the plasma emission is dominated bycontinuous light emission. Only after a certaindelay can the characteristic optical emission ofthe elements be detected. However, different ele-ments may reveal maximum characteristic opti-cal emissions at different delays after the laser

Figure 4. The SSEF GemLIBS system consists of asample chamber with an attached pulsed Nd:YAG

laser, a series of high-resolution fiber-optic spectrom-eters, the laser power supply, and a computer for

controlling the system and analyzing the spectra.Photo by H. A. Hänni, © SSEF.

Figure 5. Thisschematic diagramshows the individualconstituents of theSSEF GemLIBS system.

pulse. We found that a delay of 2 micro-seconds was ideal for beryllium detec-tion in corundum.

We performed extensive testing to minimizethe possibility of laser-induced internal damageto the gem sample. We established that a laserenergy of 100 mJ is ideal for Be detection in acorundum matrix. At this energy, the laser abla-tion spot on the surface of the gemstone is mini-mized and internal damage is avoided. Higherenergies (e.g., 150 or 200 mJ) may lead to damage,as part of the laser energy is transmitted throughthe sample, resulting in small disc-like tensioncracks along the laser path. Note, too, that theanalyzed spot should not be located close to anear-surface fracture or inclusion, as in rare casesthis may cause a tiny tension crack. It is there-fore recommended that a gemologist examine thesample with a microscope before choosing thespot for LIBS analysis.

With our optimized setup, the tiny laser spotson a sample’s surface have a diameter of lessthan 0.1 mm (100 µm) and a maximum depth of30–50 µm (figure 6). This is similar to the size ofthe laser holes generated by LA-ICP-MS. TheLIBS laser spots may be detected by a closeinspection of the sample with a 10¥ loupe, butthey do not affect the overall appearance of thegemstone. As the vaporized portion of the sam-ple is redeposited around the hole after thebreakdown of the plasma, a small iridescent zonemay be visible around the LIBS spot (about 2 mmin diameter). It can be easily removed with aslight repolishing. By analyzing faceted sampleson or near their girdle, the tiny laser spots areinconsequential. The girdle also is of interestbecause it is usually rather poorly repolishedafter treatment, thus offering a better possibilityof finding minute areas that are filled with resid-ual Be-enriched flux material (Hänni and Pettke,2002; Emmett et al.; 2003). For the detection ofBe-diffusion treatment by LIBS, a maximum oftwo or three spots is chosen for analysis.

RESULTSThe LIBS spectra were averaged from 20 individuallaser pulses to obtain the best counting statisticsover the whole broad-band range from 200 to 980nm (see, e.g., figure 7). The highest peaks in theultraviolet to mid-visible spectral range are due toAl. The peaks in the upper spectral range (>600 nm)

are mainly due to oxygen and some nitrogen fromthe atmosphere (air).

Figure 8 compares the LIBS spectra of the Bediffusion–treated sapphires (Be-1–Be-6 and BeS-1)to those of two Be-free flame-fusion synthetic

Figure 7. This LIBS spectrum of a purple Be-diffusedsapphire (sample Be-1) shows the full spectral rangebetween 200 and 980 nm. Numerous atomic andionic emission lines are present, which may partiallyinterfere with one another. The main peaks are due toaluminum. Emission due to beryllium produces apeak at approximately 313.08 nm.

Figure 6. Two LIBS laser spots are visible near the gir-dle of this yellow sapphire. A micrometer scale isshown for comparison. The diameter of these tinylaser spots is less than 0.1 mm, similar to that of theholes produced by LA-ICP-MS. They are hardly visiblewith 10¥ magnification, and are particularly incon-spicuous when located on or near the girdle (photo byH. A. Hänni, © SSEF). The SEM image in the insetshows a closer view of a LIBS laser hole, which in thiscase is about 0.03 mm deep (micrograph by M.Düggelin, © SEM Laboratory, University of Basel,Switzerland).

1 mm

NOTES AND NEW TECHNIQUES GEMS & GEMOLOGY WINTER 2004 319

corundum samples (NBeS-1 and NBeS-2). Thedominant (and truncated) peaks at about 308 and309 nm are due to the Al in corundum. The spec-tra are shown without normalization of the Al IIemission at 309.27 nm. Nevertheless, there is adistinct positive correlation between the heightof the 313.08 nm Be peak and the beryllium con-centration as measured by LA-ICP-MS. At a lowconcentration of 2–3 ppm (BeS-1), the Be peak isvery small. The LIBS analyses on this cleaved Be-doped synthetic sample were taken close to the

LA-ICP-MS spots, near the rim. Based on theanalysis of this sample, we estimate that thedetection limit for Be in corundum is ~2 ppmwith our LIBS system.

At a much higher Be concentration (Be-1,34–49 ppm), the Be peak measured with LIBS wasmuch stronger. The range of Be indicated for eachsample in table 2 is based on several LA-ICP-MSanalyses and reflects the inhomogeneity of thesesamples (especially sample Be-2, with concentra-tions ranging from 5 to 21 ppm Be). As each spec-

320 NOTES AND NEW TECHNIQUES GEMS & GEMOLOGY WINTER 2004

Figure 8. These LIBSspectra in the range of307–317 nm are of Be-treated sapphires (Be-1to Be-6) and an orangeBe-doped flame-fusionsynthetic sapphire (BeS-1) shown in comparisonto the spectra of two Be-free flame-fusion syn-thetic samples (NBeS-1and NBeS-2). The313.08 nm Be peak isthe basis for the detec-tion of Be-treated sap-phires. Fortunately, thispeak does not exactlyoverlap any of thenumerous Cr and Vpeaks in that region.

Figure 9. The LIBS spec-tra of the samples thatwere either untreated or heated by traditionalmethods (NBe-1 toNBe-15) do not show Beemission at 313.08 nm.The dominant peaks atabout 308 and 309 nmare due to Al.

trum in figure 8 represents a single LIBS spot, itreflects only the Be concentration at that particu-lar location. Consequently, to better characterize asample with LIBS, it is often useful to analyze thestone in several places.

The spectra of two beryllium-free synthetic sam-ples showed no Be peak at 313.08 nm, but they didshow several peaks in the 310–314 nm region (fig-ure 8) that are due to chromium (NBeS-1) and vana-dium (NBeS-2).

Figure 9 presents the LIBS spectra of all thecorundum samples that were not subjected to Be-diffusion treatment. The spectra are quite uniform,and none shows a Be peak at 313.08 nm. Althoughthe composition of these samples varied (especiallyCr and V), there do not appear to be any distinctchromium or vanadium emissions in the spectralrange of 307–317 nm.

DISCUSSIONOur investigations show that Be-diffused sapphirescan be reliably detected by LIBS. In one sample(BeS-1), our system was able to detect a Be con-centration as low as ~2–3 ppm. As discussed byPisutha-Arnoud et al. (2004), very low Be concen-trations (on the order of 3 ppm) may result in theformation of a stable yellow (or brown, in Fe-freestones) color center in corundum, and thisappears to be the case for the orange syntheticsapphire (BeS-1).

The Be diffusion–treated natural sapphires (Be-1to Be-6) showed distinctly higher Be concentrationsthan the Be-doped synthetic sample. The levels ofBe measured by LA-ICP-MS in these samples (4–49ppm Be) are consistent with those reported for Be-diffused sapphires in the literature (see, e.g., Hänniand Pettke, 2002; Emmett et al., 2003). All the LIBSspectra from these samples showed a moderate todistinct Be emission peak centered at 313.08 nm.

A comparison of the Be-containing samples withthe two untreated flame-fusion synthetics revealedno peak overlap at 313.08 nm from the corundummatrix. Chromium and vanadium peaks may be inthe same range near 313 nm, as shown by the highlyCr- and V-doped synthetic samples (NBeS-1 andNBeS-2; figure 8), but they do not exactly overlapwith Be emission. Potentially overlapping emissionsfrom other elements were not observed; their emis-sion intensity in the corundum matrix is too low toproduce any interference with the Be emission at313 nm.

In the natural untreated or traditionally heatedcorundum samples (NBe-1 to NBe-15), no Beemission at 313 nm could be detected. This wasexpected since LA-ICP-MS data on three of thesamples (NBe-1, NBe-6, NBe-14) showed thatberyllium was below the detection limit (general-ly <0.3–0.8 ppm).

CONCLUSIONSOur investigations using the modified OceanOptics LIBS 2000+ system (SSEF GemLIBS) weresuccessful in detecting Be-diffusion of corundum.Based on extensive research, we have developed ananalytical technique for routine testing of facetedcorundum for the presence of beryllium.

Compared to other methods of Be detection,LIBS has several advantages. The sample prepara-tion is very simple (i.e., attaching the stone to aglass plate with Blu-Tack), and no vacuum is need-ed for analysis. The LIBS instrument is much lessexpensive than SIMS or LA-ICP-MS, and it also iseasier to maintain. (As a general rule, a LIBS sys-tem costs US$20,000–$90,000, whereas LA-ICP-MS ranges from $200,000 to $500,000 and SIMSmay run from $750,000 to over $2,000,000.) Whenequipped with broad-band spectrometers, LIBS iscapable of simultaneous multi-element detection(from low to high atomic weights). The detectionlimit for Be in corundum is quite low, at about 2ppm (depending on the experimental parameters).After calibration and validation of a specific LIBSsystem, Be detection in corundum can be done byknowledgeable lab personnel without extensivetraining.

A disadvantage of LIBS is that it is slightlydestructive. Even when it is properly used, the laserleaves small spots on the surface of the gemstone,similar to other Be detection methods such as LA-ICP-MS and SIMS. Also, the LIBS technique onlyyields qualitative to semiquantitative data, unlikethe other two Be-detection techniques.

This article describes the first systematic use ofLIBS in gemology, that is, for the detection of Be-diffused sapphires. LIBS may also have somepotential for determining the geographic origin ofgemstones and identifying color modification inpearls and other gem materials, since this tech-nique can detect a full range of elements, even attrace levels. Moreover, its relatively low costmakes it a viable technique for many gemologicallaboratories.

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322 NOTES AND NEW TECHNIQUES GEMS & GEMOLOGY WINTER 2004

ABOUT THE AUTHORS

Dr. Krzemnicki is a gemologist and director of education atthe SSEF Swiss Gemmological Institute in Basel, Switzerland.Dr. Hänni is director of SSEF and professor at the Universityof Basel, Switzerland. Dr. Walters is vice president ofresearch and development at Ocean Optics Inc., Orlando,Florida.

ACKNOWLEDGMENTS: The authors thank Kees Van DeSteeg, Richard Grootveld, and all of the staff at Ocean OpticsInc. for their support during the installation of the LIBS instru-ment at SSEF. Further thanks go to Hans-Ruedi Rüegg of the

Mineralogical Institute, University of Basel, for technical assis-tance. LA-ICP-MS analyses were carried out at the Institute ofMineral Resources at the Swiss Federal Institute ofTechnology (ETH) Zurich by Dr. Thomas Pettke, under thedirection of Dr. Christoph Heinrich. Greatly appreciated arediscussions with, and information provided by, Dr. DetlefGünther (ETH Zurich, Switzerland), Dr. Johannes Heitz(Johannes Kepler University, Linz, Austria), and Dr. JohnEmmett (Crystal Chemistry, Brush Prairie, Washington). Wethank Werner Spaltenstein (Multicolor Ltd., Chanthaburi,Thailand) and Djeva S.A. (Monthey, Switzerland) for donatingsamples for this research.

REFERENCES Allemand C.D. (1972) Spectroscopy of single-spike laser-generat-

ed plasmas. Spectrochimica Acta Part B, Vol. 27, pp. 185–188.Bogue R.W. (2004) Boom time for LIBS technology. Sensor

Review, Vol. 24, No. 4, pp. 353–357.Brech F., Cross L. (1962) Optical microemission stimulated by a

ruby maser. Applied Spectroscopy, Vol. 16, p. 59.Carranza J.E., Hahn D.W. (2002) Assessment of the upper particle

size limit for quantitative analysis of aerosols using laser-induced breakdown spectroscopy. Analytical Chemistry, Vol.74, No. 21, pp. 5450–5454.

Corney A. (1977) Atomic and Laser Spectroscopy. ClarendonPress, Oxford, England.

Emmett J.L., Scarratt K., McClure S.F., Moses T., Douthit T.R.,Hughes R., Novak S., Shigley J.E., Wang W., Bordelon O.,Kane R.E. (2003) Beryllium diffusion of ruby and sapphire.Gems & Gemology, Vol. 39, No. 2, pp. 84–135.

García-Ayuso L.E., Amador-Hernández J., Fernández-RomeroJ.M., Luque de Castro M.D. (2002) Characterization of jew-ellery products by laser-induced breakdown spectroscopy.Analytica Chimica Acta, Vol. 457, No. 2, pp. 247–256.

Gruber J., Heitz J., Arnold N., Bäuerle D., Ramaseder N., MeyerW., Hochörtler J., Koch F., (2004) In-situ analysis of metalmelts in metallurgic vacuum devices by laser-induced break-down spectroscopy. Applied Spectroscopy, Vol. 58, No. 4, pp.457–462.

Guillong M., Günther D. (2001) Quasi “non-destructive” laserablation–inductively coupled plasma–mass spectrometry fin-gerprinting of sapphires. Spectrochimica Acta Part B, Vol. 56,No. 6, pp. 1219–1231.

Günther D., Frischknecht R., Heinrich C.A. (1997) Capabilitiesof an argon fluoride 193 nm excimer laser for a laser ablationinductively coupled plasma mass spectrometry microanalysisof geological materials. Journal of Analytical Atomic Spec-

trometry, Vol. 12, pp. 939–944.Hänni H.A., Pettke T. (2002) Eine neue Diffusionsbehandlung

liefert orangefarbene und gelbe Saphire. Gemmologie:Zeitschrift der Deutschen Gemmologischen Gesellschaft,Vol. 51, No. 4, pp. 137–152.

Hänni H.A., Krzemnicki M.S., Kiefert L., Chalain J.P. (2004) Einneues Instrument für die analytische Gemmologie: LIBS.Gemmologie: Zeitschrift der Deutschen GemmologischenGesellschaft, Vol. 53, No. 2/3, pp. 79–86.

Hänni H.A., Krzemnicki M.S. (2004) A new tool in analyticalgemology: LIBS. 29th International Gemological Congress,Wuhan, China, p. 63.

Krzemnicki M.S., Hänni H.A. (2004) The potential of LIBS ingemstone testing: Detection of Be-diffusion treated corundumand determination of country of origin based on chemicalfingerprinting. 3rd International Conference on LaserInduced Plasma Spectroscopy and Applications, September28–October 1, Malaga, Spain.

McClure S., Moses T., Wang W., Hall M., Koivula J.I. (2002) GemNews International: A new corundum treatment fromThailand. Gems & Gemology, Vol. 38, No. 1, pp. 86–90.

Peretti A., Günther D. (2002) Colour enhancement of naturalfancy sapphires with a new heat-treatment technique (Part A).Contributions to Gemmology, Vol. 1, pp. 1–48.

Pisutha-Arnoud V., Häger T., Wathanakul P., Atichat W. (2004)Yellow and brown coloration in beryllium treated sapphires.Journal of Gemmology, Vol. 29, No. 2, pp. 77–103.

Radziemski L.J., Cremers D.A., Loree T.R. (1983) Detection ofberyllium by laser-induced-breakdown spectroscopy.Spectrochimica Acta Part B, Vol. 38, No. 1/2, pp. 349–355.

Scarratt K. (2002) Orange-pink sapphire alert. American GemTrade Association, www.agta.org/consumer/gtclab/orange-sapphirealert.htm.

www.gia.edu/gemsandgemology

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LAB NOTES GEMS & GEMOLOGY WINTER 2004 323

Faceted APOPHYLLITEWith “Crop Circles” Although apophyllite is found inbeautiful transparent colorless topale green tetragonal crystals of rela-tively good size, it is virtually un-heard of as a faceted gemstone. Onthe one hand, its perfect basal {001}cleavage makes it difficult to cut. Onthe other, as a hydrated silicate[(KCa4Si8O20(OH,F)•8H2O], apophyl-lite is also very susceptible to heatdamage, so even the friction fromgrinding and polishing on a lap cangenerate enough heat to cause crack-ing. It was therefore of interest to doc-ument gemologically the 6.28 ct near-colorless oval modified brilliant cut(13.11 ¥ 11.48 ¥ 9.31 mm) apophyllite

shown in figure 1, the first facetedapophyllite we have seen in the labo-ratory. The gem, from Poona, India (alocality famous for apophyllite), wasprovided for examination by interna-tionally known Scottish gemologistAlan Hodgkinson.

True to its nature, this facetedapophyllite had a relatively largecleavage open to the surface (again,see figure 1), which was clearly visi-ble through the table facet. Thecleavage was oriented in a planeslightly off parallel to the table, analignment that was probably inten-tional. Had the planes of the tableand the cleavage been parallel, itwould have been virtually impossibleto get a good polish on the table facet.

Gemological identification wasrelatively straightforward, with onlystandard instruments needed. Whenthe stone was examined through thetable facet, a uniaxial optic figurewas clearly visible in polarized light.The refractive index was recorded as no = 1.531 and ne = 1.534 inmonochromatic near-sodium equiva-lent light, with a corresponding bire-fringence of 0.003. The stone wasinert to both long- and short-waveultraviolet radiation, and the hydro-static specific gravity was 2.38.

As seen in figure 2, the most strik-ing feature of this gem was the condi-tion of its internal cleavage surfaceswhen viewed with magnification.Rather than being more or less “feath-ery” in appearance, as is common onfresh cleavage surfaces, this particularcleavage was relatively smooth. It

showed distinctive rectangular, circu-lar, and square patterns, with some

© 2004 Gemological Institute of America

GEMS & GEMOLOGY, Vol. 40, No. 4, pp. 323–333

Editor’s note: The initials at the end of each itemidentify the editor(s) or contributing editor(s)who provided that item. Full names are given forother GIA Gem Laboratory contributors.

EDITORSThomas M. Moses, Ilene Reinitz, Shane F. McClure, and Mary L. JohnsonGIA Gem Laboratory

CONTRIBUTING EDITORSG. Robert CrowningshieldGIA Gem Laboratory, East Coast

Cheryl Y. WentzellGIA Gem Laboratory, West Coast

Figure 1. This 6.28 ct stone—fromPoona, India—is the first facetedapophyllite we have encounteredin the laboratory. Note the slightiridescence visible beneath thetable facet.

Figure 2. With 15¥ magnification,the apophyllite’s perfect basal{001} cleavage shows a pleasing“crop circle” geometry colored bybright interference colors.

squares being contained in the centersof the circles. This was somewhatreminiscent of the infamous and rela-tively controversial “crop circles” thathave been found in some farm fields.From the overall appearance of theinner walls of the cleavage, we suspectthat the interesting geometric formswere the result of regrowth, ratherthan post-growth etching.

John I. Koivula and Maha Tannous

DIAMONDLuminescent “Hopper” DiamondThe vast majority of the diamondsgraded by the GIA Gem Laboratory arepolished goods, so we enjoy the oppor-tunity to examine natural diamondcrystals that exhibit attractive colorsor shapes, as well as other features.Such crystals are “gems” in their ownright, and because of their intriguingbeauty they often remain in their natu-ral state, uncut. It was therefore withinterest that we recently examined a2.03 ct transparent, near-colorless dia-mond cube that showed significanthopper growth (that is, where the faceshave grown more at the edges and cor-ners than in the center) and etching,with the center of each of the cubefaces depressed and the edges and cor-ners extended (figure 3).

The crystal, which measured 5.90¥ 5.72 ¥ 5.67 mm, was purchased inAntwerp by Chris Amo of CEO

Enterprises, Amherst, New York. Hespotted it at a diamond cutting factoryas it was being checked for UV lumi-nescence. The crystal stood outimmediately because of its bright yel-low fluorescence to long-wave UVradiation, and the fact it looked like aglowing star when viewed in a direc-tion toward a corner point (figure 4).After purchasing the crystal, whichwas in a parcel of rough diamondsreportedly from the DemocraticRepublic of the Congo, Mr. Amo soldit to gem and mineral collectorWilliam W. Pinch of Rochester, NewYork, who in turn provided it to thelaboratory for examination.

Strain was visible in the diamondcrystal when it was examined withmagnification between crossed polar-izers; the strain colors served to high-light the cubic etch figures and othersurface contours (figure 5) visible onall the crystal’s faces. Using the deepUV radiation of the Diamond TradingCompany (DTC) DiamondView, wedid not observe any growth zoning.Fourier-transform infrared (FTIR) spec-trometry showed that the crystal wasa type IaA, with significant amountsof both nitrogen and hydrogen.

It is not often that we see a crystal,such as this diamond from the Congo,

that possesses all the attributes (beau-ty, durability, and rarity) required of agem, as well as distinctive fluores-cence and surface features.

John I. Koivula, Maha Tannous, and Christopher M. Breeding

“Magnetic” Natural Pink DiamondOne interesting feature of some syn-thetic diamonds is their attraction to asimple magnet. (Strictly speaking, dia-monds do not possess any magnetism.)This apparent “magnetism” is due tothe existence of metallic inclusions—usually the flux materials, such as Fe,Ni, or Co, used in the growth process.While magnetism is a very good indi-cation that a diamond is synthetic,some rare exceptions do exist.

Recently, a 0.12 ct Fancy Intensepurplish pink diamond (figure 6) sub-mitted to the West Coast laboratorydemonstrated apparent magnetism(figure 7). In addition to pink graining,magnification revealed several inclu-sions, among them “feathers” and

324 LAB NOTES GEMS & GEMOLOGY WINTER 2004

Figure 3. Note the cavernousappearance seen on the faces of this2.03 ct “hopper” diamond crystal.

Figure 4. When viewed directlytoward a corner, this 2.03 ctetched diamond cube showed anobvious stellate form that was fur-ther accentuated by the strong yel-low fluorescence to long-wave UV.

Figure 5. Viewed between crossedpolarizers with 10¥ magnification,intense strain colors in the 2.03 ctdiamond highlight the cubic etchpits and related surface contours.

dark features, a few of which reachedthe surface. Some of these featureshad a platy habit, while others wereirregular in shape. The diamond alsohad several cavities on the girdle andpavilion facets that were filled with adark material. It had a few cloud-likepatches of pinpoint inclusions, buttheir appearance was different fromthe clouds we have seen in syntheticdiamonds. When observed with a

desk-model spectroscope, the dia-mond showed only a 415 nm “Cape”line. It fluoresced blue to standardlong-wave UV radiation, and yellowand blue to short-wave UV. Whenexamined with the DTC Diamond-View fluorescence imaging system(figure 8), it did not show the cross-shaped zoning typically seen in mostsynthetic diamonds. Last, no bandsthat could be attributed to Ni or otherflux metals were observed in the pho-toluminescence spectrum. On thebasis of these results, we concludedthat the diamond was natural.

When a magnet was brought closeto the diamond, however, it attractedthe dark material that was exposed incavities along the girdle (figure 9).When we analyzed this dark materialusing energy-dispersive X-ray fluores-cence (EDXRF) spectroscopy, wefound Fe and Ca to be the major com-ponents. We studied the exposed darkmaterial further using Raman spec-troscopy and found features that couldbe attributed to hematite, limonite(rust), and diamond. We concludedthat this dark material was residuefrom the manufacturing process.Metallic fragments within the residuecaused the magnetic behavior of thissample, while oxidation of the ironfragments generated the hematite andlimonite peaks observed in the Ramanspectra. We attempted to analyze thedark inclusions in the diamond withRaman spectroscopy, but the spectradid not reveal any recognizable fea-tures. Raman analyses of some ofthese inclusions where they reachedthe surface produced spectra similar tothe spectrum of the dark material inthe cavities, but this also may be fromresidue covering those inclusions.

The magnetic response of this natu-ral diamond was similar in intensity towhat we have seen in synthetic dia-monds with metallic inclusions.Cleaning the diamond with acid wouldpresumably dissolve this residue, andthereby render the diamond “nonmag-netic.” Attraction to a magnet remainsa useful way to check for synthetic dia-monds, but as with other gem testingmethods, this should not be the soleidentification criterion.

Andy H. Shen and James E. Shigley

Diamond with Many Microscopic Carbonate InclusionsMineral and fluid inclusions in dia-mond have been studied extensively,because of the unique informationthey offer about diamond formationand the geochemistry of the Earth’smantle. Carbonate, phosphate, andwater inclusions of microscopic scalealso have been reported in the coatingson many of those natural diamonds

Figure 8. In this fluorescenceimage recorded with the DTCDiamondView, the cross-shapedzoning pattern typical of mostsynthetic diamonds is absent.The residue-filled surface cavitiescan be seen along the girdle onthe left side of the diamond.

Figure 9. This photomicrographshows the residue-filled surfacecavities along the girdle of thediamond. Chemical analysis byEDXRF revealed the presence ofFe and Ca in the residue.Magnified 60¥.

Figure 6. This 0.12 ct FancyIntense purplish pink natural dia-mond demonstrated apparentmagnetism.

Figure 7. Because of iron-contain-ing residue in surface cavities,this diamond could be suspendedwhen touched by a magnet.

LAB NOTES GEMS & GEMOLOGY WINTER 2004 325

326 LAB NOTES GEMS & GEMOLOGY WINTER 2004

that have a translucent outside “skin”and a transparent gem-quality core(see, e.g., O. Navon et al., “Mantle-derived fluids in diamond micro-inclu-sions,” Nature, Vol. 335, 1988, pp.784–789). Ranging up to 1 mm thick,these coatings generally are removedby the cutting and polishing process,although coatings on some (usually

very small) cuboid opaque diamondscould extend to the central part of thecrystals. The East Coast laboratoryrecently examined a faceted diamond(figure 10) that had dense microscopiccarbonate inclusions similar to thosefound in such coatings; however, themicro-inclusions occurred throughoutthe entire stone, with relatively largeparticles aligned in many nearly paral-lel bands (figure 11). These inclusions

also showed some interesting featuresin their composition.

The 2.38 ct round brilliant cut(8.63 ¥ 8.66 ¥ 5.27 mm) was colorgraded Fancy Dark brown–greenishyellow, and its clarity was at the bot-tom of the GIA clarity grading scale.Indeed, it was translucent due to themicro-inclusions. No transparentregion was observed even with mag-nification. Infrared absorption spec-troscopy showed that the diamondwas a type IaA, with very low nitro-gen but relatively high hydrogen con-centrations (figure 12). Strong absorp-tions at 1471–1433 and 874 cm-1, anda weak but sharp absorption at 729cm-1, from micro-inclusions of calciteand dolomite-ankerite were detected.These features are similar to thoseobserved for micro-inclusions in dia-mond coatings. However, a strongand sharp peak at 3698 cm-1 also wasobserved, which is not present incoatings and rarely occurs in dia-mond. Another unusual feature ofthis diamond was that no water com-ponent was detected. Water is verycommon in diamond coatings, andthe absence of water and the relative-ly large size of this diamond indicatethat it crystallized in a stable carbon-ate-rich and water-poor environment.

Despite the low clarity, this dia-mond was of interest due to thenumerous micro-carbonate inclusionsand their uniform arrangement.

Wuyi Wang and TMM

Unusual Near-Colorless SYNTHETIC DIAMONDRecently, a 0.32 ct near-colorlessround brilliant was submitted to theWest Coast laboratory for a DiamondDossier report. Gemological examina-tion of the inclusions and spectroscop-ic analysis suggested that this was nota typical diamond. Further testingwith the DTC DiamondView instru-ment strongly indicated that the dia-mond was, in fact, a synthetic.Although GIA does not provide coloror clarity grading services for syntheticdiamonds, had this been a natural

Figure 12. The IR absorption spectrum of this unusual diamond revealedthe presence of calcite and dolomite-ankerite (i.e., features at 1471–1433,874, and 729 cm-1). The absorption at 3698 cm-1 is rarely observed in dia-mond or its inclusions; its assignment is unclear.

Figure 10. This 2.38 ct FancyDark brown–greenish yellow dia-mond contains numerous micro-scopic carbonate inclusions.

Figure 11. Micro-inclusions occurthroughout the 2.38 ct diamond,and relatively large particles arealigned to form many nearly par-allel bands. Width of the image is 3.2 mm.

stone it would have been equivalentto the VS range in clarity, with only afew small inclusions in the crown,and approximately I color.

It is extraordinary to encountersuch a high-quality near-colorless syn-thetic diamond in the marketplace,because this material is extremely dif-ficult to grow by conventional highpressure/high temperature processes.Considerable effort and expense mustbe undertaken to prevent nitrogen(which causes yellow in diamonds)from being incorporated during dia-mond growth. Furthermore, the pro-cesses required to limit nitrogenalmost always result in abundant,readily visible inclusions.

Previous researchers have de-scribed experimental synthetic dia-monds from De Beers and GeneralElectric Co. that showed propertiessimilar to this sample (see, e.g., J. E.Shigley et al., “Gemological propertiesof near-colorless synthetic diamonds,”Spring 1997 Gems & Gemology, pp.42–53). Because of the rarity of thistype of near-colorless synthetic dia-mond, a full description of its proper-ties is presented here.

Microscopic examination revealedopaque metallic-appearing inclusions,pinpoint inclusions, and a number ofvery thin, translucent, parallelogram-shaped platelets that appeared gray-blue to brown and transparent intransmitted light (figure 13). Similarinclusions were described by Shigleyet al.; however, those platelets weretriangular. When viewed betweencrossed polarizing filters, anomalousbirefringence (“strain”) was observedto be associated with the platelets;but the cross-hatched, or “tatami,”strain typical of natural type IIa dia-monds was absent. A cloud of veryfine pinpoint inclusions, similar tothose often seen in synthetic dia-monds, was evenly distributedthroughout the sample, although itwas not dense enough to have a sig-nificant effect on clarity. The opaqueinclusions in this synthetic diamondappeared as fine black rods, needles,or sub-rounded particles in transmit-ted light. Several of these reached the

surface and appeared metallic and“gold” colored in reflected light. Theopaque inclusions were not attracted

to a magnet, and Raman spectroscopysuggested that they consisted of non-diamond, carbon-rich material.

All known colorless and near-col-orless synthetic diamonds are type IIa;that is, they are effectively nitrogen-free. While spectroscopic analysisusually indicates that natural type IIadiamonds do contain very smallamounts of nitrogen, absorption andphotoluminescence spectra showedno evidence of nitrogen in this sam-ple. However, the mid-infraredabsorption spectrum displayed a fea-ture at 2803 cm-1, which indicates thepresence of small amounts of boron(figure 14). Consistent with this find-ing, the sample was electrically con-ductive in a few directions.

When examined with long-waveUV radiation, the synthetic diamondwas inert and showed no phosphores-cence. The short-wave reaction wasan unevenly distributed weak yellow-ish green, with a weak to moderategreenish phosphorescence that lastedmore than one minute. Cathodo-luminescence and DiamondView

Figure 13. This 0.32 ct near-colorlesssynthetic diamond, submitted tothe lab for a grading report, revealedopaque metallic-appearing inclu-sions, “pinpoints,” and numerousparallelogram-shaped platelets.Reflected light, magnified 35¥.

Figure 14. The mid-infrared absorption spectrum of this synthetic dia-mond indicates the presence of small amounts of boron, as demonstratedby the feature at 2803 cm-1. As would be expected, the synthetic diamondwas electrically conductive in some directions.

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328 LAB NOTES GEMS & GEMOLOGY WINTER 2004

reactions were pale blue and uneven,with a cuboctahedral growth pattern(i.e., square and cross-shaped zones) aswell as strong blue phosphorescence,both of which are typical of syntheticdiamonds (figure 15).

Although the rarity of high-quali-ty colorless synthetic diamondsmakes it easy to believe that one willnot encounter such material in thetrade, this sample serves as a strongreminder that these diamonds doexist and can be difficult for gemolo-gists to identify without very carefulexamination of inclusions and fluo-rescence reactions.

Kimberly M. Rockwell

Orangy Brown IOLITEFrom MadagascarA 4.45 ct transparent orangy brownoval modified brilliant was recentlysubmitted to the West Coast laborato-ry for identification (figure 16) byMark Kaufman of Kaufman Enter-prises, San Diego, California. Gemo-logical testing revealed that it wasbiaxial with R.I.’s of 1.532–1.541(birefringence 0.009) and an S.G. of2.57 (determined hydrostatically). Itdid not fluoresce to either long- orshort-wave UV radiation and had onlya weak-to-medium absorption bandcentered at 490 nm. The stone wasrepresented as iolite from Mada-gascar, and the properties we recorded

were consistent with those previouslyreported in the literature for this gem(see R. Webster, Gems, 5th ed., rev. byP. G. Read, Butterworth-Heinemann,Oxford, 1994, pp. 345–346). Due to itsunusual color, we decided to performRaman analysis, which confirmedthat it was indeed iolite. Microscopicexamination of the stone revealedfractures, iridescent dust-like particlesthroughout, “fingerprints,” short nee-dles, and spotty orange-brown colorconcentrations, along with unusual“roiled” growth zoning.

Most in the trade are familiar withthe gem iolite (also known ascordierite) and its typical, attractivevioletish blue color. It usually hasstrong pleochroism, consisting of deep

violetish blue and near-colorless tolight yellow-brown colors that can beobserved without the aid of a polariz-ing filter (see Spring 2001 Gem NewsInternational, pp. 69–70). The iolitereported here also displayed fairlystrong pleochroism, but the strengthsof the individual colors were reversed.Whereas the violetish blue pleochroiccolor is typically the strongest iniolite, this orangy brown iolite’s domi-nant pleochroic color was yellow-orange. It did have a grayish violetpleochroic component, but this wasquite a bit weaker than the yellow-orange, so much so that it was noteasily visible with the unaided eye.

In researching this material, wefound very few references that listedbrown as a possible color for iolite,and even the ones we found statedthat this color was rare. None of thegemologists in the West Coast lab hadpreviously seen an iolite of this color.

Elizabeth P. Quinn

Flashing LABRADORITELabradorite is a relatively commonmember of the feldspar group. It is socommon, in fact, that large polishedslabs of rock containing labradores-cent phenocrysts of this mineral areused in the building and constructionindustries for walls and countertops.Like all gem materials, however,there is a very limited supply of fine-quality labradorite suitable for gemand jewelry applications.

The West Coast laboratory recent-ly examined two well-polishedlabradorite gems, said to be fromIndia, that were sent to us by lapidaryLeon M. Agee of Deer Park, Washing-ton. These stones displayed veryattractive and dramatic bandedlabradorescence, which seemed toflash as the stones and/or overheadlight source were moved back andforth in a direction perpendicular tothe obvious lamellar twin structure.

The larger of the two stones wasan 85.58 ct polished trapezoidal piecethat measured 40.15 ¥ 28.16 ¥ 8.61mm, while the other was a 34.98 ct

Figure 16. This 4.45 ct orangybrown stone proved to be iolite.The color is very unusual for iolite,which is typically violetish blue.

Figure 15. Cathodoluminescence (left) and DTC DiamondView (right)testing of the near-colorless synthetic diamond showed the cuboctahedralgrowth pattern and strong blue phosphorescence typical of synthetics.

oval cabochon measuring 33.09 ¥14.30 x 6.17 mm. As shown in figure17, the labradorescence presenteditself in relatively typical intense-to-muted shades of blue, green, and yel-low. In addition to the labradorescentflash shown by both stones, the cabo-chon displayed a blue chatoyant band(also seen in figure 17), which seemedto be independent of the shift in colorof the lamellar twin layers.

The labradorescent shift was par-

ticularly interesting when viewedwith low magnification. As seen infigure 18 (left), almost the entire sur-face area displayed labradorescentinterference colors; only a few thinbands appeared dark. When the lightposition was shifted 90° across thestone (figure 18, right), the broad col-ored areas went dark, while the once-dark thin twin layers showed brightlabradorescence.

John I. Koivula and Maha Tannous

Natural Saltwater Mussel PEARLSNacreous saltwater pearls almostinvariably originate from oysters (e.g.,Pinctada sp. and Pteria sterna) or oneof several species of abalone. Althoughthere are some attractive non-nacreous“pearls” that originate from variousmollusks (conch, melo melo, scallop,clam, etc.), it is rare to see attractive,colorful nacreous pearls from such anordinary bivalve as a common saltwa-ter mussel. The West Coast laboratoryrecently had the opportunity to exam-ine two such natural pearls. The firstwas a 22.77 ct grayish purple and whitebaroque-shape pearl (figure 19) submit-ted by Jeremy Norris of Oasis Pearl inAlbion, California. Mr. Norris report-ed that the pearl was recovered from the Pacific Coast of Baja California,Mexico. He also provided a shell of thesaltwater mussel species from whichhe thought the pearl originated (again,see figure 19). Comparison to photos of various saltwater mussels and con-sultations with malacological expertsindicated that the shell was that of Mytilus californianus, the Californiamussel (2004 pers. comms. from, e.g.,Paul Valentich-Scott, Curator of Mala-cology, Santa Barbara Museum ofNatural History).

The first task was to determinewhether the specimen was a truenacreous pearl. This was readilyproved by examination with magnifi-cation, which revealed a nacre plateletstructure. However, the appearance ofthe overlapped “suture lines” (figure20) differed from that seen in an oysterpearl, suggesting that it was fromanother type of mollusk.

X-radiography revealed a struc-ture that was typical of naturalpearls. Long-wave UV fluorescencewas very weak dark brown to inert,mottled with weak light yellow andmoderate to strong whitish areas thatcorresponded to the white areas onthe pearl.

The pearl did not fluoresce to X-rays, which is typical for dark-coloredpearls regardless of their freshwater orsaltwater origin. EDXRF analysis,however, confirmed the absence of

Figure 17. Accented by their characteristic labradorescent colors, thesetwo phenomenal labradorites, weighing 85.58 and 34.98 ct, show distinctlamellar twinning. The cabochon also displays chatoyancy.

Figure 18. When examined with low (5¥) magnification, almost the entireimaged surface of the trapezoidal labradorite displayed interference col-ors, with only a few thin twin bands remaining dark (left). When the inci-dent light was shifted 90° (right), the thin twin layers showed labradores-cence, while the rest of the stone went dark.

LAB NOTES GEMS & GEMOLOGY WINTER 2004 329

330 LAB NOTES GEMS & GEMOLOGY WINTER 2004

Mn, which proved the pearl was ofsaltwater origin.

With the saltwater mussel shellavailable, we decided to obtain UV-Vis and Raman spectra for both thepearl and the shell to see if there wasa close correlation between the two.In fact, the UV-Vis reflectance spectraproved to be very similar, with atransmission maximum centeredaround 600 nm that would contributeto the reddish modifying component

in the color of the pearl. Likewise, theRaman spectra for the pearl and theshell were nearly identical, with twodistinct peaks at approximately 1094and 1482 cm-1 that are consistentwith the presence of carotenes.

These matching spectra wouldsuggest that the pearl originated from

this, or a closely related, type of mol-lusk. However, since it could not beconfirmed that the pearl was pro-duced by the type of mussel whoseshell was provided, Mr. Norris sent usanother darker, but very similar, 3.82ct grayish purple mussel pearl with anaccompanying shell that a local fish-erman stated was the same as thehost of that pearl (figure 21). Mr.Norris reported that these items alsowere recovered from the Pacific Coastof Baja California, where they arefound in intertidal, estuary, and man-grove areas. Although the interior ofthe M. californianus shell contained asmall patch of highly iridescent nacretoward its outer edge (again, see figure19), the color of this area and the darkviolet pigments in the colored part ofthe shell interior did not closelyresemble that of the pearl’s nacre. Thesecond saltwater mussel shell, how-ever, was smaller, slightly differentfrom the first, and had an interiormother-of-pearl surface with a reddishpurple color that closely matched thatof the two pearls (again, see figure 21).Experts agreed that the smaller shellwas that of Modiolus capax (e.g., P.Valentich-Scott, pers. comm., 2004).M. capax, the fat-horse mussel, has a

Figure 20. The suture lines of thismussel pearl are notably differentfrom those of saltwater oysterpearls, with a textured zone alongthe leading edge that causes themto appear coarser and morebroadly defined. Magnified 25¥.

Figure 19. This attractive grayish purple pearl (18.35 ¥ 16.30 ¥ 10.85 mm)is shown with a saltwater mussel shell from Mytilus californianus (theCalifornia mussel). Both were recovered from the Pacific Coast of BajaCalifornia, Mexico.

Figure 21. This smaller, darker grayish purple pearl (10.15 ¥ 9.15 ¥ 5.75mm) rests on the shell of the saltwater mussel Modiolus capax (also foundin Mexico), which has an interior surface that more closely matches theappearance of both this pearl and the one in figure 19.

reddish shell, a nacreous interior, andgrows up to approximately 14 cm inlength, a size capable of producing thelarge pearl shown in figure 19. LikeM. californianus, it is also of the fami-ly Mytilidae.

UV-Vis and Raman spectra werecollected for the second pearl andshell specimens to compare with thefirst. The UV-Vis reflectance spectrawere all very similar to each other,and the Raman spectra were all near-ly identical, with the same caroteneabsorption peaks. The Raman spectraalso matched those for another com-mon North American saltwater mus-sel that was found in Carlsbad,California, most likely a Mytilus gal-loprovincialis (European blue musselor bay mussel). The similaritiesamong these Raman spectra are incontrast to the distinct differencesfrom those for a pink conch pearl,which had a CaCO3 peak at 1085 cm-1

and carotene peaks at 1124 and 1512cm-1, as well as from those of severalpurple to pink freshwater pearls,which had a 1084 cm-1 CaCO3 peakand carotene peaks at 1130 and 1523cm-1. The similarity in the databetween the purple saltwater pearlsand their accompanying musselshells, along with the dissimilarity todata collected from more disparatespecies, strongly indicated that thepurple pearls originated from one of agroup of closely related mussels,probably of the Mytilidae family, andquite possibly from genus Modiolus.

CYW and Shane Elen

Treated-Color “Golden” South Sea CULTURED PEARLSDetermining the origin of color for“golden” South Sea cultured pearlshas been an increasingly importantchallenge in recent years. The growingdemand for these cultured pearls, forwhich natural-color supplies are limit-ed, has led to a greater variety of treat-ed-color products in the marketplace.

Two recent G&G articles by S.Elen addressed the identification oftreated-color “golden” South Sea

pearls (“Spectral reflectance and fluo-rescence characteristics of natural-color and heat-treated ‘golden’ SouthSea cultured pearls,” Summer 2001,pp. 114–123; “Update on the identifi-cation of treated ‘golden’ South Seacultured pearls,” Summer 2002, pp.156–159). The 2001 article showedthat the natural-color cultured pearlsexhibit a broad absorption featurefrom 330 to 460 nm, which is thecombination of two individualabsorption features: 330–385 nm and385–460 nm. The treated-color“golden” South Sea cultured pearlsexamined had UV-visible absorptionfeatures in the 330–385 nm regionthat were consistently weaker thanthose of their natural-color counter-parts. Some—but not all—of thetreated-color samples also exhibitedcolor concentrations in nacre defectsand/or around the drill holes.

The East Coast laboratory recentlyexamined three strands containing atotal of 87 drop-shaped “golden”South Sea cultured pearls (as indicatedby X-radiography) ranging from 18.15¥ 15.55 ¥ 14.90 mm to 13.50 ¥ 12.45 ¥12.10 mm. The overall color was anunnatural orangy yellow with an

unusual pinkish cast evident in somelighting conditions (figure 22). With10¥ magnification, all these culturedpearls showed a slightly mottled nacrewith small raised spots and patches.They also exhibited visible signs ofdye, including an unevenly distributedcolor accompanied by small concen-trations of a deep red dye. Some of thedyed areas were dendritic in shape,whereas others were visible below thesurface, indicating the cultured pearlswere dyed after drilling.

Reflectance spectra were collect-ed for all 87 of the cultured pearls(figure 23). We then compared thereflectance spectra of these treated-color samples to the spectrum of anatural-color cultured pearl shown inElen (2001, figure 8). The natural-color spectrum exhibited the charac-teristic broad absorption from 330 to460 nm, with stronger absorption inthe UV (330–385 nm) than in theblue (385–460 nm). The treated-colorcultured pearls showed increasedabsorption (i.e., lower reflectance) at~305 nm, in contrast to the well-defined reflectance feature in natural-color cultured pearls. A very weak~345 nm absorption and a 415–430

Figure 22. These three strands of drop-shaped “golden” South Sea culturedpearls proved to be treated color.

LAB NOTES GEMS & GEMOLOGY WINTER 2004 331

nm absorption feature for 84 of the87 treated-color cultured pearls wereconsistent with the Elen results, par-ticularly for orangy yellow treated-color cultured pearls (see Elen, 2001,figure 9).

These results support Elen’s con-clusion that the absence of a 330–385nm absorption is characteristic oftreated-color “golden” culturedpearls. In addition, the absence of awell-defined reflectance feature at~305 nm was characteristic of thesetreated-color “golden” culturedpearls. Differences between the spec-tra of the treated-color samples inElen’s studies and those describedhere probably result from differencesin the pre-treatment characteristicsof the cultured pearls and/or varia-tions in the treatment method.

Carolyn van der Bogert

QUARTZ in Three ColorsIn the Spring 2003 Lab Notes section(pp. 44–45), we discussed how somegem materials gain apparent bodycol-or through the presence of brightlycolored inclusions. The material fea-tured in that note was quartz that

was colored dark grayish blue by ran-domly scattered indicolite rods andneedles. Apparent blue color in natu-ral quartz was also mentioned asresulting from various other mineralinclusions, among them ajoite, ahydrated potassium sodium copperaluminum silicate hydroxide.

The West Coast laboratory recent-ly had the opportunity to examine afreeform step-cut quartz (figure 24,

left) that was colored a pleasing lightblue by the presence of numerousfibers of ajoite (figure 25), which wereidentified by Raman analysis. This3.52 ct gem (15.50 ¥ 9.49 ¥ 6.17 mm)was faceted by Art Grant of Coast toCoast Rare Gems in Martville, NewYork, who sent it to the laboratory forexamination. The original roughmaterial was from the Messina mine,Transvaal, Republic of South Africa, alocality well known among collectorsfor its specimens of quartz with inclu-sions of copper minerals.

At approximately the same time,the laboratory received for study twoadditional faceted quartzes that werecolored by mineral inclusions. Thelargest of these was a 9.41 ct shield-shaped step cut (figure 24, center)that was fashioned from Russian“strawberry” quartz by Leon M.Agee. As expected for so-called straw-berry quartz, and as shown in figure26, this stone was colored by ultra-thin intense red inclusions ofhematite (identified by Raman analy-sis), but it was unusual for the inten-sity and evenness of the color.

The third quartz (figure 24, right)was a 3.38 ct mottled dark green, pear-shaped step cut provided for examina-tion by mineral collector Edward R.Swoboda of Beverly Hills, California,who reported that the locality wasKastamonu, in northern Turkey.

332 LAB NOTES GEMS & GEMOLOGY WINTER 2004

Figure 24. These three quartz gems are colored by mineral inclusions.Left to right, the color results from ajoite (3.52 ct), hematite (9.41 ct),and népouite (3.38 ct).

Figure 23. The South Sea cultured pearls in this study exhibited absorp-tion features at ~345 and 415–430 nm that previously were reported intreated-color cultured pearls. The absence of a 305 nm reflectance featureis also consistent with treatment; natural-color cultured pearls show awell-defined 305 nm reflectance feature. (The spectrum of a natural-colororangy yellow pearl shown here is from Elen, 2001.)

Magnification showed that the greenbodycolor came from numerous densesprays and compact masses of a greenmineral (figure 27). X-ray powderdiffraction analysis of a small amountscraped from the surface of the stonerevealed the mineral to be a closematch for népouite, a nickeliferousmember of the kaolinite-serpentinegroup.

These three gems illustrate howmineral inclusions can provide verypleasing colors to stones that wouldotherwise be near-colorless. In allthree cases, we were told, the color

provided by the inclusions was themain reason these stones were cut.

John I. Koivula, Maha Tannous, and Dino DeGhionno

ERRATUMThe clarity-enhanced ruby entry inthe Fall 2004 Lab Notes section (pp.247–249) incorrectly stated that theglassy residue left by heat treatmentof natural rubies can facilitate thepartial healing of a fracture. It is fluxthat facilitates partial healing by dis-solving the walls of a fracture, and

then new crystallization (syntheticgrowth) occurs. The areas closest tothe walls of a fracture are often syn-thetic corundum, and the center ofthe “filled fracture” is a noncrys-talline glass byproduct.

PHOTO CREDITSMaha Tannous—1, 3, 4, 6, 7, 15–17, and24; John I. Koivula—2, 5, 18, 20, and25–27; Andy Shen—8 and 9; ElizabethSchrader—10 and 22; Wuyi Wang—11;Shane F. McClure—13; C. D. Mengason—19 and 21.

Figure 25. Colored by the presenceof copper, these ajoite fibers areresponsible for the blue face-upappearance of their otherwise col-orless quartz host. Magnified 15¥.

Figure 26. This quartz gained itscolor from the presence of numer-ous red transparent-to-translu-cent inclusions of hematite.Magnified 10¥.

Figure 27. The green color of thisquartz was provided by numerousdense sprays and compact massesof népouite, which in turn gets itscolor from nickel. Magnified 10¥.

LAB NOTES GEMS & GEMOLOGY WINTER 2004 333

diamonds,” Diamond and Related Materials, Vol. 11, 2001,pp. 125–131) and others have attributed a number of photo-luminescence features detected in natural diamonds tonickel. More recently, the UV-Vis-NIR optical centers relat-ed to Ni and nickel-nitrogen complexes in a natural dia-mond were published by J.-P. Chalain (see the Winter 2003Gem News International section, pp. 325–326).

The present contributors recently analyzed a saturatedorangy yellow 1.33 ct natural diamond (figure 1) that con-tained elevated contents of Ni and exhibited very interest-ing properties. The diamond fluoresced pinkish orange toboth long- and short-wave UV excitation, which is a veryrare emission color for diamond. Yellow phosphorescencelasting several seconds also was observed, which wasmore distinct after short-wave UV excitation.

Internal features consisted of fractures and distinctetch channels, some with a tabular appearance (figure 1,inset). The morphology of these etch channels resembledthat of the metallic flux inclusions in some HPHT-grownsynthetic diamonds. These inclusions are sometimes dis-solved during particular post-growth conditions, leavingbehind hollow channels.

Infrared spectroscopy revealed that this was a low-

DIAMONDS A natural diamond with very high Ni content. Nickel indiamond (as point defects and nickel-nitrogen complexes) ismainly known in synthetics that are grown from a Ni-con-taining catalyst. These synthetic diamonds may contain alarge number of Ni-related absorption features in a wideregion of the spectrum, from the UV to the NIR (S. C. Lawson, and H. Kanda, “An annealing study of nickelpoint defects in high-pressure synthetic diamond,” Journalof Applied Physics, Vol. 73, No. 8, 1993, pp. 3967–3973).The presence of trace Ni impurities in natural diamonds hasbeen known for years, but little has been published on theassociated spectral features. K. Iakoubovskii and G. J.Adriaenssens (“Optical characterization of natural Argyle

334 GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004

EDITORBrendan M. Laurs ([email protected])

CONTRIBUTING EDITORSEmmanuel Fritsch, IMN, University of Nantes, France ([email protected])

Henry A. Hänni, SSEF, Basel, Switzerland([email protected])

Kenneth V. G. Scarratt, AGTA Gemological TestingCenter, New York ([email protected])

Karl Schmetzer, Petershausen, Germany ([email protected])

James E. Shigley, GIA Research,Carlsbad, California ([email protected])

Christopher P. Smith, GIA Gem Laboratory,New York ([email protected])

Editor’s note: The initials at the end of each item identify the editor or contributing editor who provided it. Full names and affiliations are given for other contributors.

Interested contributors should send information andillustrations to Brendan Laurs at [email protected] (e-mail), 760-603-4595 (fax), or GIA, 5345 Armada Drive, Carlsbad, CA 92008. Original photos will be returned after considera-tion or publication.GEMS & GEMOLOGY, Vol. 40, No. 4, pp. 334–357© 2004 Gemological Institute of America

Figure 1. This 1.33 ct orangy yellow natural diamonddisplayed unusual Ni-related absorption features. Thestone contains numerous hollow etch channels (seeinset; magnified 25×), some of which appear dark inthe photo of the diamond. Photos by F. Notari.

Figure 2. The FTIR spec-trum indicates that thesample is a low-nitrogentype IaA natural diamondwith a distinct Ib charac-ter, as shown by peaks at1359 and 1237 cm−1 andseveral sharp absorptionsbetween 3270 and ~3000cm−1 (see insets). Thespectrum proves naturalorigin, since most of thesefeatures are unknown insynthetic diamonds.

Figure 3. Numerous absorp-tions are evident in this low-temperature Vis-NIR spectrumof the diamond. The insetview of the 560–940 nm regionshows two separately recordedspectra from this sample todemonstrate the reproducibili-ty of the small absorptions.Besides the possibly oscillatingnature of the defect(s) respon-sible for the 600–720 nmabsorptions, the vibronicnature of the broad band at800 nm with its zero phononline at 891 nm is apparent.

GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004 335

nitrogen type IaA diamond with a very distinct Ib charac-ter, as shown by peaks at 1359 and 1237 cm−1 and severalsharp, weak absorptions between 3270 and ~3000 cm−1,with main features at 3180 and 3143 cm−1 (figure 2; see G. S. Woods and A. T. Collins, “Infrared absorption spectraof hydrogen complexes in type I diamonds,” Journal ofPhysics and Chemistry of Solids, Vol. 44, No. 5, 1983, pp.471–475). This spectrum indicated natural origin, sincemost of the features recorded are unknown in syntheticdiamonds.

A low-temperature Vis-NIR spectrum in the 400–1000nm range was recorded to detect possible color treatment(figure 3). This spectrum was very unusual and exhibited atleast 36 absorptions, with multiple oscillations between600 and 720 nm. These oscillations are apparent as two dis-tinct groups of absorptions with individual peaks that showregular spacing (i.e., 6–9 nm for the first group [610–647nm] and about 8–9 nm for the second group [686–720 nm]).The oscillating nature of the second group is clearer thanthe first, which has rather variable spacing, intensity, and

curve shapes (see figure 3, inset). Such spectral properties indiamond have been reported before, and the oscillatingnature of the defects has been documented by I. M. Reinitzet al. (“An oscillating visible light optical center in somenatural green to yellow diamonds,” Diamond and RelatedMaterials, Vol. 7, 1998, pp. 313–316). Those authors indi-cated that such a spectrum is extremely rare and possiblydue to vibronic interactions of some unknown molecularspecies, particularly in green diamonds. In contrast, the sat-urated orangy yellow color of the 1.33 ct diamonddescribed here can be explained by the absence of the twobroad bands centered at ~700 and 600 nm, as seen in thespectrum of a green diamond published by Reinitz et al.The transmission window in the green part of the spec-trum of the 1.33 ct diamond is distinctly weaker, so thestone appears yellow. There is no indication that the colorof this diamond resulted from a treatment process.

A strong absorption at 891 nm (not mentioned byReinitz et al., since their spectra did not extend above 850nm) appeared to be a “normal” zero-phonon line, and thus

336 GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004

the broad band centered at approximately 800 nm can beinterpreted as the vibronic structure of this defect (again,see figure 3). To our knowledge, this is the first time thatthe 891 nm system has been documented in any diamond,natural or synthetic.

In our experience, the general appearance and posi-tions of several absorptions in this spectrum have distinctsimilarities to the spectra of certain synthetic diamondsgrown with a Ni catalyst, especially after annealing athigh temperature. We have recorded Vis-NIR spectra ofhigh-Ni synthetic diamonds with up to 25 sharp absorp-tions between 470 and 819 nm. Some of the absorptionsseen in the spectrum of the 1.33 ct orangy yellow dia-mond were detected by us in a Ni-rich dark yellow-brownGemesis synthetic diamond (i.e., at 572, 610, 617, 647,661, 670, 694, 711, 747, and 819 nm). In contrast, thecombination of bands at 426 and 480 nm is known in nat-ural diamonds exhibiting a thermochroic and photochroiccolor change, the so-called “chameleon” diamonds (E.Fritsch, et al., “Examination of the twenty-two caratgreen chameleon diamond,” in D. J. Content, Ed., AGreen Diamond: A Study of Chameleonism, W. S.Maney & Son, Leeds, England, 1995, p. 25). Such dia-monds also exhibit an 800 nm band, although they lackthe vibronic structure seen in the spectrum of this sam-ple. The 426 nm band provides additional proof that thisis a natural diamond.

The low-temperature photoluminescence spectrum ofthe diamond provided further evidence of Ni-related defects(figure 4). The PL spectrum was very similar to those ofchameleon diamonds analyzed by these contributors, and

many of the observed emissions correspond to known fea-tures that are assigned to Ni point defects and nickel-nitro-gen complexes. The features at 639, 657, 677, 690, 705, 723,739, 800, and 884 nm seen in this diamond have been iden-tified in Ni-catalyst synthetic diamonds and attributed tonickel defects (A. M. Zaitsev, Optical Properties ofDiamond: A Data Handbook, Springer-Verlag, Berlin, 2001,pp. 140–197). In addition to these, the present authors knowof emissions at 581, 590, 604, 616, 647, and 756 nm in syn-thetic diamonds grown from a Ni-containing catalyst.

EDXRF spectroscopy of the diamond revealed distinctpeaks for both Ni and Fe. From the spectrum we estimatedthe Ni content of the diamond at 30–50 ppm. While the Fecontent was not too unusual for a natural diamond, thedetection of Ni by EDXRF spectroscopy has so far beenrestricted to synthetic diamonds grown by the tempera-ture gradient method using a Ni-containing catalyst (J. E.Shigley et al., “Gemesis laboratory-created diamonds,”Winter 2002 Gems & Gemology, pp. 301–309). In naturaldiamonds, the Ni content is generally far too low to bedetected by this method.

The same holds true for UV-Vis-NIR absorption spec-troscopy, by which Ni point defects and nickel-nitrogencomplexes can be identified in synthetic diamonds; incontrast, Ni-related features in natural diamonds are veryrarely detected by this method. The only nondestructivemethod to effectively detect extremely low Ni contentsin diamond is photoluminescence spectroscopy (seeZaitsev, 2001).

The complex Vis-NIR and PL spectra of this diamondare explained with high probability by the presence of anunusually high concentration of Ni-related defects. Ourobservation of many absorptions at approximately equalpositions in the Vis-NIR and PL spectra of Ni-catalystsynthetic diamonds, combined with the detection ofremarkable amounts of Ni in the 1.33 ct stone by EDXRF,lead us to propose that at least some of the many peaks inthese spectra are due to naturally occurring Ni and/ornickel-nitrogen complexes. It would be very surprisingnot to detect Ni-related optical absorptions in the PL andVis-NIR spectra of a diamond with such elevated Ni con-tent, especially after the natural annealing this stonemust have experienced, since substantial amounts of itsnitrogen were aggregated. Further chemical analyses ofdiamonds exhibiting these spectral features will be per-formed to confirm these findings as we encounter theappropriate samples.

We thank Dr. Ilene Reinitz of the GIA Gem Laboratoryin New York for reviewing this report.

Thomas Hainschwang ([email protected])Gemlab Gemological Laboratory

Vaduz, Principality of Liechtenstein

Franck Notari GemTechLab Laboratory

Geneva, Switzerland

Figure 4. The low-temperature photoluminescencespectrum of the diamond exhibits several emissionsthat appear to be Ni-related. The inset shows theweak Ni-related feature at 884 nm plus a weak 930nm peak of unknown origin.

GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004 337

COLORED STONES ANDORGANIC MATERIALSAdularescent chalcedony from Iran. Since 2003, violetchalcedony showing adularescence has been recoveredfrom the Qom area near the Qom Salt Lake, about 150 kmsouth-southwest of Tehran (figure 5). This area is under-lain by Eocene andesite volcanic rocks. The chalcedony isfound as irregular nodules that are mostly covered by glau-conite, a green potassium-iron silicate (see figure 5, inset).

Mechanized mining is done by a group of geologistsfrom Tehran, in an area measuring about 700 m2. They pro-duce approximately 800 kg of the chalcedony each month,but only a small portion (±150 kg) shows the violet color inmoderate tones. Overall, the material ranges from lightgrayish violet to dark violet. In addition to the violet chal-cedony, the area has yielded pink, yellow, and brown agate.

Cutting machines have been purchased fromGermany, and the miners are planning to construct a pol-ishing workshop in the future. So far, approximately 30 kgof rough violet chalcedony has been processed, yielding 8kg of cabochons (ranging from 10 to 20 ct) and some pol-ished slabs.

A 22.57 ct cabochon of grayish violet chalcedony dis-playing weak-to-moderate adularescence (figure 6) wasexamined by one of us (EPQ), and the following propertieswere recorded: diaphaneity—translucent; R.I.—1.538 (fromthe flat back); S.G.—2.59; Chelsea filter reaction—none;fluorescence—inert to long- and short-wave UV radiation;and no absorption lines were visible with the desk-modelspectroscope. These properties are consistent with thosereported for chalcedony by R. Webster (Gems, 5th ed.,revised by P. Read, Butterworth-Heinemann, Oxford,England, 1994, pp. 232–233). Microscopic examination ofthe cabochon revealed a “fingerprint” and some agate-likecolor banding along with a very subtle botryoidal structure.

Makhmout Douman ([email protected])Arzawa Mineralogical Inc., New York

Elizabeth P. QuinnGIA Gem Laboratory, Carlsbad

Clinohumite from the Pamir Mountains, Tajikistan.Clinohumite, (Mg,Fe2+)9(SiO4)4(F,OH)2, is a rather uncom-mon gem material that has a Mohs hardness of 6 and typ-ically ranges from orangy yellow to brownish orange.Although faceted examples of clinohumite have beendocumented previously in Gems & Gemology (see LabNotes, Winter 1986, p. 236 and Spring 1988, pp. 47–48;and Spring 1991 Gem News, p. 48), a recent increase inthe availability of this material prompted this update.Samples and information were provided to these contrib-utors by Vladyslav Yavorskyy of Yavorskyy Co. Ltd.,Bangkok, who is marketing clinohumite from the PamirMountains of Tajikistan as “Sunflower stone.”According to Mr. Yavorskyy, gem-quality clinohumitealso is known from two localities in Russia: the southern

Lake Baikal area and the Taymyr region of northernSiberia. The Pamirs constitute the main source, however,and over the past two decades Mr. Yavorskyy has stock-

Figure 6. This 22.57 ct cabochon of adularescent chal-cedony from Iran is shown together with a piece of therough material. The banding that is visible in portionsof the rough is typically excluded from the polishedstones, to achieve a homogeneous appearance. Cour-tesy of Makhmout Douman; photo by Maha Tannous.

Figure 5. Violet chalcedony showing adularescence isbeing mined from the Qom area of central Iran. Fromleft to right, Dr. Edib Dariush, two local miners, andMakhmout Douman are shown with some recent pro-duction; the mining pit can be seen in the back-ground. The inset shows irregular nodules of the chal-cedony that are partially covered by green glauconite.Photos courtesy of Makhmout Douman.

338 GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004

piled a few hundred faceted stones from this mining area(see “‘Sunflower stone’ debuts in Asia,” Jewellery NewsAsia, No. 242, October 2004, p. 30).

According to Mr. Yavorskyy, clean faceted stones fromthe Pamirs usually weigh less than 1 ct, and those in the1–3 ct range are very rare. However, over the past few yearssome larger stones from this area have been cut, weighingup to 17.87 ct (U. Henn et al., “Gem-quality clinohumitefrom Tajikistan and the Taymyr region, northern Siberia,”Journal of Gemmology, Vol. 27, No. 6, 2001, pp. 335–339).Most of the material contains noticeable eye-visible inclu-sions. The rough is mined by local people during the shortsummer season (June–August). Mineral dealer FarooqHashmi (Intimate Gems, Jamaica, New York) reports thatsince the fall of the Taliban, some of the material has beensmuggled into Afghanistan and eventually is traded inPeshawar, Pakistan. The rough is often sold as orangespinel (referred to as “lal” locally), since many of thetraders are not familiar with clinohumite and it is com-monly found in association with gem-quality spinel. Thespinel and clinohumite occur in skarns at several localitiesin the southwestern Pamir Mountains (e.g., Kukh-i-Lal,Sumdzin, Changin), typically within altered gneiss adjacentto magnesian marbles (A. K. Litvinenko, “Nuristan–SouthPamir province of Precambrian gems,” Geology of OreDeposits, Vol. 46, No. 4, 2004, pp. 263–268).

Mr. Yavorskyy loaned two faceted stones (0.68 and1.59 ct) and one crystal of Tajikistan clinohumite to GIAfor examination (figure 7). The following properties wererecorded by one of us (EPQ) on the faceted stones: color—orange and orange-yellow, with moderate pleochroism inorange and yellow; diaphaneity—transparent; R.I.—1.632–1.665 and 1.632–1.666; birefringence—0.033 and0.034; S.G.—3.23 and 3.21; Chelsea filter reaction—none;both stones were inert to long-wave UV radiation but dis-played a characteristic moderate to strong chalky orange-yellow fluorescence to short-wave UV; and both displayeda general absorption to 430 nm with a desk-model spec-

troscope. Microscopic examination revealed two-phaseinclusions, twin planes and transparent straight and angu-lar growth lines in both stones. In addition, the 0.68 ctsample had a fracture that showed evidence of clarityenhancement, and the 1.59 ct stone contained “finger-prints” and mineral inclusions (transparent, near-color-less, low-relief, birefringent crystals) that could not beidentified by Raman spectroscopy due to their position inthe stone.

The properties of these two samples are comparable tothose reported for clinohumite in mineralogical referencebooks (as well as those listed by Henn et al. [2001] and inthe Lab Notes and Gem News entries listed above),although their S.G. values were slightly higher than thosetypically reported from the Pamirs (3.23 and 3.21 vs. 3.18).

BML

Elizabeth P. Quinn

Corundum-fuchsite-kyanite rock from India. A colorfulnew gem material was offered at the Tucson gem showslast February. Although this material—ruby/pink sapphirein a mottled green groundmass—sometimes resemblesruby in zoisite, the green component is mostly fuchsite, agreen, chromium-rich variety of muscovite mica. A fewsamples were purchased separately by two GIA employ-ees. Three of these samples were chosen for characteriza-tion (figure 8). The two cabochons (2.87 and 12.68 ct) werepurchased from Rare Earth Mining Co., Trumbull,Connecticut, and the polished freeform (206.46 ct) wasobtained from Jewel Tunnel Imports, Baldwin Park,California. All the samples were reportedly from India, andthe larger piece was said specifically to be from Mysore.

The following gemological properties were determined:color—variegated and mottled bluish green to green andpurplish pink to purplish red, sometimes with grayish blueand/or brownish white zones; diaphaneity—translucent toopaque; R.I. spot readings—1.76 from the pink/red zones,1.57 or 1.58 from the various green zones, and 1.71 fromthe blue zones; Chelsea filter reaction—strong red reactionfrom the pink/red zones and pink to red reaction from thebluish green and blue-green zones, as well as the greengroundmass. The pink/red portions fluoresced a mottledstrong red to long-wave UV radiation and weak red toshort-wave UV, whereas the bluish green, blue-green, andbrownish white zones fluoresced a mottled weak-to-medi-um chalky blue to long-wave UV and a mottled very weakchalky blue to short-wave UV. For the most part, the greengroundmass and grayish blue zones were inert to bothlong- and short-wave UV. With the desk-model spectro-scope, we observed a typical ruby spectrum from thepink/red zones and lines in the red region of the spectrumfrom all the green areas. These properties confirm that thepurplish red/pink zones were ruby/sapphire. They alsoindicate that the green zones, including the groundmass,are chromium rich. To confirm the identity of the green

Figure 7. Clinohumite is an uncommon gem thatcomes mainly from the Pamir Mountains ofTajikistan. The faceted examples shown here weigh0.68 and 1.59 ct. Courtesy of Yavorskyy Co. Ltd.;photo by Maha Tannous.

zones and better identify the grayish blue material, weturned to Raman analysis.

Raman analysis of the bluish green to green areasshowed the presence of fuchsite mica, which is consistentwith the characteristics given above. Considering the het-erogeneous nature of this rock, additional minerals aremost likely present in the bluish green to green areas—thisis supported by differences in UV fluorescence of the dif-ferent green zones. The grayish blue zones (which, whenpresent, surrounded the corundum; see the large polishedfreeform in figure 8) were identified as kyanite; this also issupported by the limited gemological measurements thatcould be performed on these areas. The brownish whitezones contained a mica, but the particular species couldnot be confirmed with Raman analysis.

Shortly after the Tucson show, Bill Heher of Rare EarthMining Co., Trumbull, Connecticut, reported that there isa good supply of the rough material, and he has obtainedapproximately 75 kg so far. The material originallyappeared on the market as obelisks and spheres. He alsomentioned that some of the more highly fractured piecesare commonly stabilized with epoxy resin. We confirmedthis by carefully testing the three samples with a thermalreaction tester (TRT). The polished freeform and thesmaller cabochon sweated readily to the TRT; the latterstone also contained large, obviously filled cavities. Thelarger cabochon did not show evidence of a filler.

Although samples of this material that lack kyanitecould be mistaken for the well-known ruby-in-zoisite fromTanzania, they are readily recognizable by the distinctivemicaceous texture of the fuchsite. Similar corundum-fuch-site-kyanite assemblages have been documented fromZimbabwe and South Africa (C. C. Milisenda, “Gemmolo-gie Aktuell: Ruby-fuchsite-kyanite rock from India,”Gemmologie: Zeitschrift der Deutschen GemmologischenGesellschaft, Vol. 52, No. 4, 2003, pp. 124–125).

Elizabeth P. Quinn ([email protected])

A new gem material from Madagascar: A mixture of cris-tobalite and opal. These contributors recently studied around, milky white, 6.84 ct cabochon (figure 9) fromMadagascar. The spot refractive index was 1.45, typical foropal, but the hydrostatic S.G. value was 2.18, which ishigher than expected for an opal with that R.I. Based onextensive opal research done by one of these contributors(EF), an opal with this R.I. would be expected to have anS.G. value in the range of 1.98–2.10. Therefore, we exam-ined the sample in more detail to check for the presence ofinclusions, or another factor that would cause this anoma-lous behavior.

When viewed with a microscope, this sample present-ed two unusual characteristics: (1) a central apparent sepa-ration plane; and (2) sphere-, spicule-, and rod-like polariza-tion features. The sphere-like features, which were about0.5 mm in diameter, revealed a typical uniaxial optic fig-ure between crossed polarizers, with a fibrous, polycrys-talline rim of about 0.1 mm.

As we suspected the material to be opal, we used X-raydiffraction (XRD) and Raman scattering to investigate thesample further. Through the use of a special sample holder,XRD analysis was performed nondestructively on the near-flat base of the cabochon with a D-5000 Bruker powderdiffractometer and a fixed reflection geometry. Accordingto our reference (J. M. Elzea and S. B. Rice, “TEM and X-raydiffraction evidence for cristobalite and tridymite stackingsequences in opal,” Clays and Clay Minerals, Vol. 44, No.4, 1996, pp. 492–500), the pattern obtained was that of α-cristobalite (a polymorph of SiO2). The full width at halfmaximum (FWHM) of the main peak was 0.08°, muchlower than that for opal-C (a poorly crystallized cristobalite,with a FWHM of 0.2 to 0.9), and even lower than that ofthe reference α-cristobalite given by Elzea and Rice (0.15).

Figure 8. The colorful patterns in these cabochons(2.87 and 12.68 ct) and polished freeform (206.46 ct)from India are created by assemblages of ruby/pinksapphire, green fuchsite, and grayish blue kyanite.Photo by Maha Tannous.

GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004 339

Figure 9. This 6.84 ct cabochon (26.5 × 26.5 × 6.8mm) from Madagascar consists of highly crystallinecristobalite and opal. Photo by Alain Cossard.

340 GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004

Even taking into account possible instrumentation differ-ences, the very small FWHM of this peak demonstrated thepresence of highly crystalline cristobalite.

Fourier-transform Raman spectra were obtained with aBruker RFS100 spectrometer. The spectrum of our sample(figure 10) was compared to reference spectra of opal-C fromMexico and α-cristobalite (taken from devitrified glass, atypical reference standard for cristobalite due to the largeamount of material present). On the basis of this compar-ison, we concluded that our sample was a mixture of α-cristobalite and opal-C. The spectrum was dominated bycristobalite features, in particular peaks at 418 and 230 cm−1,but there were small features typical of opal-C (or opal-CT,composed of disordered cristobalite with some tridymite-like stacking) at 1194 and 955 cm−1, which are absent fromthe spectrum of cristobalite. In addition, the water signalaround 3000 cm−1 was dominated by the water signal ofopal, with a broad band centered at about 3220 cm−1. Theabsence of “cristobalitic” water in the spectrum indicatedthat the cristobalite crystals in our sample contained littlewater compared to our reference devitrified glass specimen.

In XRD, the signal from a crystalline phase will alwaysdominate the diffractogram; hence, it was not surprisingthat the opal signal was missing from our pattern, whichwas dominated by α-cristobalite. Also, the presence ofcristobalite explains the relatively high S.G. value. As inmany materials consisting of admixtures with silica, theR.I. is dominated by the silica matrix, whereas the S.G.reveals the presence of the included phase. Here the R.I. istypical for opal (1.45, versus 1.485 for cristobalite), but theS.G. of 2.18 is clearly affected by the presence of cristobalite(2.27–2.32); as noted, a typical S.G. value for opal with an

R.I. of 1.45 is about 2.0. The cristobalite is apparently pre-sent as submicroscopic domains, as evidenced by the con-sistency of Raman spectra recorded on multiple points ofthe cabochon. The milky appearance of the material is con-sistent with the scattering of light from a mixture of submi-croscopic domains, in this case of cristobalite and opal.

To the best of our knowledge, this is the first time thata mixture of highly crystalline cristobalite and opal hasbeen documented as a gem material.

Since characterizing this cabochon, we have had achance to briefly examine additional samples of this milkywhite gem from Madagascar (including a 10 ct emeraldcut), which presented gemological properties and Ramanspectra that were similar to those described for the 6.84 ctcabochon. However, the separation plane and polarizationfeatures noted in that cabochon were not seen in any ofthese additional samples.

Eloïse Gaillou ([email protected]) and Blanca Mocquet

Centre de Recherches Gemmolo-giques Jean-Pierre Chenet (CRG)

Nantes, France

EF

Jeremejevite from Madagascar. In early 2004, a 7.88 ctnear-colorless faceted oval (figure 11) was purchased inMadagascar from a local dealer as “achroite” (colorlesstourmaline). The stone was uniaxial negative, but it hadhigher refractive indices and a lower birefringence thanexpected for tourmaline (1.642–1.650 and 0.008, respec-tively). It was inert to both long- and short-wave UV radia-tion. The S.G. was 3.28, which was too high for tourma-line. These properties, however, were a good match forjeremejevite. Since jeremejevite has not been documented

Figure 11. This 7.88 ct near-colorless jeremejevite rep-resents the first report of this gem species fromMadagascar. The numerous parallel channels arefilled with brown, plate-like inclusions. Photo-micrograph by E. Fritsch; magnified 2×.

Figure 10. FT-Raman spectra of α-cristobalite, opal-C,and the Madagascar cabochon are shown here. Thespectrum of the cabochon is dominated by featuresassociated with cristobalite, but there are also somesmall features typical of opal.

GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004 341

previously from Madagascar, confirmation was soughtusing chemical analysis and Raman scattering.

A Jeol 5800 scanning electron microscope with a PGTenergy-dispersive detector was used to obtain a qualita-tive chemical analysis. The only elements detected wereoxygen, fluorine, and aluminum. Since the chemical com-position of jeremejevite is Al6B5O15(F,OH)3, the analysiswas consistent with that gem, and the absence of siliconruled out tourmaline. A quantitative analysis was notpossible since neither boron nor hydrogen can be detectedwith this instrument.

Raman spectra were obtained with two differentinstruments, a Bruker RFS100 Fourier-transform spec-trometer and a T64000 Jobin-Yvon dispersive spectrome-ter, at a resolution of approximately 4 cm−1. All spectrawere consistent, with some intensity variation dependingon crystallographic orientation. In general, the main fea-tures were sharp peaks at about 372, 328, and 178 cm−1,with slightly broader bands at about 1065 and 960 cm−1.This matched our reference spectrum for jeremejevite,obtained on a blue sample from Namibia.

These results confirmed that the stone was indeed jere-mejevite, and we believe it to be the first reported fromMadagascar. Prior to this discovery, jeremejevite wasfound principally in Namibia. The near-colorless appear-ance is unusual for this species, which is typically blue oryellow (see K. Scarratt et al., “Jeremejevite: A gemologicalupdate,” Fall 2001 Gems & Gemology, pp. 206–211).

The stone contained numerous inclusions; the mostnoticeable were tube-like features (again, see figure 11).These elongated tubes showed significant necking andcontained brown, plate-like inclusions that could be a Nb-Ta oxide, such as manganocolumbite. There were also anumber of more equant inclusions with well-defined crys-tal forms. Among these were a gray crystal with an appar-ent cubo-octahedral morphology resembling betafite oranother pyrochlore-group mineral (figure 12), and pale yel-low crystals with the appearance of feldspar or danburite(figure 13). Unfortunately, none of these well-formed

inclusions gave a useful signal when analyzed by laserRaman microspectroscopy.

According to Dr. Federico Pezzotta of the Museo Civicodi Storia Naturale, Milan, Italy, since news of the jeremeje-vite discovery reached Madagascar in early 2004, severalbuyers have purchased all the available colorless “tourma-lines” offered at the Antsirabe market. However, he is notaware of any additional samples of jeremejevite being found.Dr. Pezzotta reported that the dealer who sold the stone haspurchased rough material with her husband from variouslocations in Madagascar for several years. It was impossiblefor her to recount when the rough jeremejevite was pur-chased, but she was confident that it came from local min-ers at Vohitrakanga, 65 km southwest of Antsirabe.

Blanca Mocquet ([email protected]) and Yves Lulzac

CRG, Nantes, France

EF

Kyanite from Tanzania. Over the past year, small quanti-ties of rough kyanite have been offered by local vendors inArusha, Tanzania. The blue color and elongate crystal formhave led some of the vendors to believe it was aquamarine.Dudley Blauwet of Dudley Blauwet Gems, Louisville,Colorado, saw about 10 kg of rough in March 2004, fromwhich he selected 3 kg for faceting or to sell as mineralspecimens. The crystals ranged up to 12.5 cm long andwere coated by traces of mica, which is consistent with thecommon occurrence of kyanite in micaceous metamorphicrocks. Kyanite is a widespread mineral in high-grade gneiss-es of the Arusha area (S. Muhongo et al., “Pan-African pres-sure-temperature evolution of the Merelani area in theMozambique Belt in northeast Tanzania,” Journal ofAfrican Earth Sciences, Vol. 29, No. 2, 1999, pp. 353–365).

Mr. Blauwet reported that the kyanite rough is com-monly color zoned: The pale greenish blue crystals containelongate dark blue zones. The dark blue portions are gener-ally more transparent than the pale-colored areas, so mostof the cut stones are dark blue. The yield is typically rather

Figure 12. The jeremejevite contained this large cubo-octahedral inclusion that may be betafite or anotherpyrochlore-group mineral. Photomicrograph by E.Fritsch; magnified 11×.

Figure 13. The jeremejevite also contained pale yel-low crystals that could be feldspar or danburite.Photomicrograph by E. Fritsch; magnified 9×.

342 GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004

small, however, due to cleavage problems. While it wouldbe possible to facet long stones approaching 20 ct, moredesirable length-to-width ratios are achievable only by cut-ting smaller gems.

Three emerald-cut stones (figure 14) and two kyanitecrystals were loaned, and an additional crystal was donatedto GIA, by Mr. Blauwet. The cut stones were characterizedby one of us (EPQ), and the results are summarized in table1. Microscopic examination of the two larger stonesrevealed fine needles, stringers of particles, and wispyclouds that were predominantly confined to the dark blueareas. The 5.04 ct kyanite also contained iridescent plateletsthat were predominantly confined to the dark blue portion.Using Raman analysis, we identified inclusions of near-col-orless to light brown zircon and near-colorless muscovite inthe two smaller stones, as well as near-colorless apatite inthe largest sample. Etch tubes and cleavage cracks also wereobserved in all three of the kyanites. In addition, the small-est stone contained iridescent platelets (like those seen inthe 5.04 ct stone), as well as elongate transparent near-color-less needles; however, we were not able to identify theseinclusions by Raman analysis.

Elizabeth P. Quinn

BML

Figure 14. These emerald cuts (8.66, 5.04, and 2.28 ct)show the range of color (and color zoning) seen in kyan-

ite from Tanzania. The crystal (approximately 6.7 cmlong) shows the typical occurrence of facetable dark

blue areas within the predominantly translucent palegreenish blue material. Courtesy of Dudley Blauwet

Gems; photo by Maha Tannous.

TABLE 1. Properties of three faceted kyanites from Tanzania.

Sample

2.28 ct 5.04 ct 8.66 ct

Color Light greenish blue Bi-colored: very dark Very dark blue (uneven)blue and near-colorless

Pleochroism Moderate: greenish Moderate: deep violet- Moderate: deep violet-blue and near-colorless blue and lighter blue blue and lighter blue

Diaphaneity Transparent Transparent to semi- Transparent to semi-transparent transparent

Refractive indices 1.712–1.728 1.711–1.727 1.711–1.727

Birefringence 0.016 0.016 0.016

Specific gravity 3.68 3.68 3.68

Chelsea filter reaction Strong red Weak red from the Moderate to strong red near-colorless zone, from a near-colorless and no reaction from the zone, and no reactionvery dark blue zones from the very dark blue

portions

Transmission Moderate red None Moderate red from a near-luminescence colorless zone, and none

from the very dark blueportions

UV fluorescenceLong-wave Moderate red Very weak red from the Very weak red from a

near-colorless zone, near-colorless zone,otherwise inert otherwise inert

Short-wave Very weak chalky Very weak chalky green Very weak chalky greengreen from the near-colorless from a near-colorless zone,

zone, otherwise inert otherwise inert

Absorption spectrum 680 nm line 670 nm cutoff 680 nm line and weak 450 nm line

Property

Sapphires from Afghanistan and Pakistan. Gem dealerFarooq Hashmi of Intimate Gems, Jamaica, New York,shared some information on the recent production of gem-quality sapphires from Afghanistan and Pakistan, and heloaned or donated several samples to GIA for examination.Mr. Hashmi obtained these samples during a buying tripto Peshawar, Pakistan, in early 2004.

Blue sapphire from Maydan Shahr, Afghanistan. TheSummer 2002 Gem News International section (p. 181)documented dark blue sapphires from a new deposit inAfghanistan, which was represented as “Medan Khar” inVardak Province, west of Kabul. Since that time, thisprovince has been the source of additional sapphires,reportedly from the Maydan Shahr area. It is not clear ifthis new production is from the same locality (with pho-netic allowances for the different spellings) or a differentdeposit. The sapphires are enclosed by a hard white matrix,which makes their recovery quite labor intensive. Mr.Hashmi saw several kilograms of rough in Peshawar, andmost had a hazy or velvety appearance, as well as a slightlygrayish tinge, which differed from the Afghan sapphire wereported on in 2002.

An examination of the 2.10 ct oval mixed-cut sapphirein figure 15 by one of us (EPQ) showed the following prop-erties: color—dark grayish greenish blue, with mediumbluish green and dark violetish blue dichroism; diaphane-ity—transparent; R.I.—1.761–1.770; birefringence—0.009;S.G.—4.03; fluorescence—inert to both long- and short-wave UV radiation; and strong absorption bands at 450,460, and 470 nm visible with the desk-model spectroscope.This stone displayed a medium to strong blue scatteringeffect when viewed with a fiber-optic light. This effect wascaused by the reflection of light off clouds of very fine parti-cles throughout the stone, resulting in a somewhat hazyappearance. Microscopic examination revealed a “finger-print,” a twin plane, a transparent near-colorless birefrin-gent crystal, stringers of pinpoints, and diffuse planar yel-low and blue growth banding. No evidence of heat treat-ment was detected.

Pink sapphire from Batakundi, Pakistan. According to Mr.Hashmi, pink to purple (and rarely blue) corundum has beenmined near the town of Batakundi in Pakistan’s North WestFrontier Province since 1999. Several diggings in the areahave produced mostly low-quality material, but some fac-etable stones were recovered recently. Although gemstonesexceeding 5 ct have been faceted, most weigh less than 2 ct.

Five Batakundi sapphires (0.74–1.98 ct; see, e.g., figure16) were examined by one of us (EPQ) and the followingproperties were recorded: color—purplish pink, pink, andslightly orangy pink, with moderate dichroism in purplishpink to purple-pink and pinkish orange to pink-orange;diaphaneity—transparent to semitransparent; R.I.—ne=1.759–1.760, no=1.767–1.768; birefringence—0.008;S.G.—4.00–4.03; fluorescence—moderate to strong red to

long-wave and very weak red to short-wave UV radiation.The desk-model spectroscope showed general absorption to430 nm, a weak 450 nm band, weak 470 and 480 nm lines, a550–590 nm band, and lines in the red end of the spectrum.

All but the smallest stone displayed a moderate violet-blue scattering effect when viewed with a fiber-optic light.As with the Afghan sapphire reported above, this effect wascaused by reflection of light off clouds of very fine particlesthroughout the stones, which gave them a hazy appear-ance. Microscopic examination revealed that all five sam-ples contained “fingerprints,” fractures, dark metallicinclusions, transparent near-colorless birefringent crystals(one of which was identified by Raman analysis as zircon),straight and/or angular growth banding (purplish pink topink), and short needles resembling rutile. Also presentwere twin planes in four of the stones, needles (with theappearance of boehmite) and two-phase inclusions in three

Figure 15. This 2.10 ct sapphire is reportedly fromMaydan Shahr, Afghanistan. Courtesy of IntimateGems; photo by Maha Tannous.

GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004 343

Figure 16. Batakundi, northern Pakistan, is the sourceof these purplish pink to slightly orangy pink sap-phires (0.96–1.98 ct, faceted). Courtesy of IntimateGems; photo by Maha Tannous.

344 GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004

samples, and an angular blue color zone and large transpar-ent crystals (one of which was identified by Raman analy-sis as apatite) in the smallest stone. No evidence of heattreatment was detected in any of the sapphires. However,one showed evidence of clarity enhancement (i.e., it“sweated” when tested with a thermal reaction tester).

Purple sapphire from northern Pakistan. Another depositin northern Pakistan is the source of purple sapphires. Mr.Hashmi was not able to learn the specific locality. Hereported seeing less than 1 kg of rough in the Peshawarmarket.

A 1.20 ct modified round brilliant sapphire (figure 17)from this area was studied by one of us (EPQ): color—darkpink-purple, with weak to moderate dichroism in pink-purple and orange-pink; diaphaneity—transparent; R.I.—1.761–1.769; birefringence 0.008; S.G.—4.01; fluores-cence—weak red to long-wave and inert to short-wave UVradiation; transmission luminescence—weak red. Thedesk-model spectroscope showed absorption bands at 450,460, and 470 nm, together with lines in the red part of thespectrum. Microscopic examination revealed “finger-prints,” clusters of minute transparent near-colorless bire-fringent crystals, transparent light brown crystals (two ofwhich were identified as monazite with Raman analysis),dark metallic crystals, and needles. No evidence of heattreatment was detected.

Elizabeth P. Quinn

BML

Sapphires from Baffin Island, Canada. In 2002, localprospectors Seemeega and Nowdla Aqpik discovered gem-quality sapphires in an outcrop southwest of the communi-ty of Kimmirut on the south coast of Baffin Island, Nuna-vut, northern Canada (figure 18). To date, six corundumoccurrences have been discovered over a distance of 390 m.

The original occurrence, called “Beluga,” contains deepblue sapphires with violet overtones (figure 19). Individualcrystals up to 7.7 × 2.1 cm have been recovered (again, seefigure 18), although most are in the range of 15 × 4 mm.Some of the sapphires are color-zoned (especially larger crys-tals), and may display concentric, irregular, or end-to-endvariations in hue. The smaller crystals are generally free ofinclusions, whereas the larger ones are often fractured and,in most cases, included with calcite and/or apatite. Needlesof thomsonite, a zeolite mineral, coat grain boundaries andpenetrate deeply into some of the crystals.

Most of the Beluga sapphire crystals exhibit spectacu-lar zoning in cathodoluminescence which corresponds tothe color zoning. Very faint compositional zoning wassometimes seen in backscattered-electron images obtainedwith a scanning electron microscope. Electron-microprobeanalysis of 10 sapphire samples yielded maximum TiO2and FeO values of 0.13 and 0.30 wt.%, respectively.

In August 2004, fragments of yellow, colorless, andlight blue sapphires were discovered at another occurrencelocated 50 m from the Beluga lens, over an area about 0.5 ×0.5 m. Called “Beluga South,” this locality also containsweathered fragments of a corundum-bearing plagioclase-muscovite-calcite rock. Microprobe analyses of the yellow

Figure 17. Northern Pakistan is also the source of this1.20 ct purple sapphire and crystal fragment.Courtesy of Intimate Gems; photo by Maha Tannous.

Figure 18. Deep blue sapphires were discovered insouthern Baffin Island, Canada, in 2002. One of theoriginal prospectors, Seemeega Aqpik, is shown witha matrix specimen containing a sapphire crystal thatmeasures 7.7 cm long. Photo by William Rohtert.

GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004 345

and colorless sapphires (one sample of each) showed thatthe dominant chromophore in the yellow material wasiron, with up to 0.04 wt.% FeO; all other potential chro-mophores were below the detection limit.

Two yellow sapphires from the Beluga South occur-rence were loaned to GIA for examination (1.09 and 1.47ct; figure 20). The following properties were recorded byone of us (EPQ): color—yellow to orangy yellow, with nopleochroism observed; diaphaneity—transparent; R.I.—1.758–1.766; birefringence—0.008; S.G.—3.99 and 4.01;Chelsea filter reaction—none; and fluorescence—moderateorange to long-wave and very weak orange to short-waveUV radiation. No absorption features were visible with adesk-model spectroscope. Microscopic examinationrevealed that both stones contained a few long white nee-dles, and the oval sapphire also had a single “fingerprint.”No evidence of heat treatment was seen.

The Baffin Island sapphires are hosted by calc-silicatelenses in a marble unit of the metasedimentary LakeHarbour Group, near a major terrane boundary within thePaleoproterozoic Trans-Hudson Orogen. Silica-poor (i.e.,syenitic or ijolitic) magmas may have played a role in theinitial formation of the calc-silicate lenses. The Belugasapphires occur with plagioclase, clinopyroxene, phlogo-pite, muscovite, calcite, graphite, nepheline and scapolite.Apatite, rutile, titanite, and zircon are common in the hostrock, and rare phases include chlorite, tourmaline (dravite),monazite, sanbornite, thorianite, and uraninite (identifiedby energy-dispersive spectroscopy). Petrographic studiessuggest that this diverse mineral suite formed during retro-grade metamorphism accompanied by infiltration of CO2-bearing fluids. The area also hosts other gem varieties incomplexly deformed, high-grade metamorphic rocks.These include diopside, pargasite, garnet, spinel, scapolite,tourmaline, apatite, zircon, moonstone, and lapis lazuli.The continental collision setting of southern Baffin is anal-ogous to gem-producing areas within the India-Asia colli-sion zone (i.e., from Afghanistan to Vietnam).

In late 2003, the mineral rights to the sapphire-bearingarea of southern Baffin Island were acquired by True North

Gems Inc. So far, True North has polished 137 sapphiresfrom the Beluga lens, with a total weight of 19.33 carats.The largest stone is a 0.66 ct trilliant (figure 19). In addi-tion, 67 yellow and colorless sapphires have been cut fromthe Beluga South occurrence, with a total weight of 10.62carats. The largest yellow sapphire is a 1.47 ct oval (figure20). All of the color varieties have been cut as calibratedround brilliants in sizes down to 1 mm, with most stonesmeasuring 3 mm in diameter.

Anthony N. LeCheminant([email protected])

Petrogen ConsultantsManotick, Ontario, Canada

Lee A. Groat, Gregory M. Dipple, James K. MortensenUniversity of British Columbia

Vancouver, British Columbia, Canada

Paul GertzbeinDepartment of Indian Affairs

and Northern DevelopmentIqaluit, Nunavut, Canada

William RohtertTrue North Gems Inc.

Vancouver, British Columbia, Canada

Elizabeth P. Quinn

Unusual star and “cat’s-eye” sapphire. An unusual star sap-phire was brought to the attention of these contributors byDenis Gravier of Le Minéral Brut, Poncin, France. The 1.10ct, 6-mm-diameter round cabochon had an S.G. of 3.99,R.I.’s of 1.762–1.771, and was uniaxial negative. All of theseproperties are typical for sapphire. It was inert to both long-and short-wave UV radiation. With intense pinpoint illumi-nation, a weak but well-centered six-rayed star was visible.

The most striking feature was a near-colorless bandpassing through the center of the stone (figure 21), whichwas reminiscent of a “cat’s-eye” pattern. This zone alsowas composed of corundum, as established by qualitativechemical analysis with a Jeol 5800 scanning electron

Figure 19. These sapphires are from the Beluga lens onBaffin Island. The round brilliants weigh 0.30 and 0.31ct, and the trilliant is 0.66 ct. Photo by Brad Wilson.

Figure 20. Baffin Island is also the source of these yel-low sapphires. The cushion cut weighs 1.09 ct, andthe oval is 1.47 ct. Photo by Roger Morton.

346 GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004

microscope equipped with a Princeton Gamma-Tech energy-dispersive X-ray detector for chemical analysis. The areasadjacent to this band displayed both sharp color zoning andsilk-like inclusions that were oriented parallel to theboundaries of the near-colorless area. Magnificationrevealed that the entire stone was traversed by several “fin-gerprints.” Also present were some open fractures that con-tained small amounts of a semitransparent yellow tobrown material that originated from outside of the stone.

The color zoning suggests that the sapphire formed viasimultaneous growth on both sides of the central near-colorless plate. The most logical interpretation is that thisplate acted as a seed for overgrowth. How such a perfectplate could be produced in nature is difficult to explain,but the stone showed no evidence of synthetic origin.Perhaps Gems & Gemology readers have already seen asimilar gem or can suggest a mode of formation.

EF

Y. LulzacCRG, Nantes, France

Large cat’s-eye topaz from Ukraine. Chatoyant topaz isextremely rare. Previously documented examples include3.53 and 13.90 ct stones (see Summer 1990 Gem News, p.164 [unspecified locality], and Fall 2003 Gem NewsInternational, pp. 236–237 [Myanmar]), as well as a muchlarger sample of 152 ct that originated from Brazil (see J.Hyrsl, “Some new unusual cat’s-eyes and star stones,”Journal of Gemmology, Vol. 27, No. 8, 2001, pp. 456–460).

Two cabochons of cat’s-eye topaz were recently sub-mitted to this contributor for examination by gem dealerand collector M. Steinbach of Köln, Germany. They were

cut from the same piece of rough, which originated fromthe famous gem beryl deposits in the Volhynia region ofcentral Ukraine (see, e.g., J. Sinkankas, Emerald andOther Beryls, Chilton Book Co., Radnor, PA, 1981, pp.538–539). In addition to being the first chatoyant exam-ples of topaz from this area known to this contributor,these cabochons were quite large: 270 ct (figure 22) and154 ct. They were identified as topaz by traditionalgemological methods, and their identity was confirmedby Raman spectroscopy.

Both samples were intrinsically colorless and revealednumerous partially healed fractures consisting of liquidand two-phase (liquid/gas) inclusions, which gave thestones a somewhat milky appearance. The chatoyancywas caused by numerous extremely thin parallel channelsor tubes, which commonly showed a brownish or reddishbrown staining. The staining of these fine tubes createdthe apparent pale brown bodycolor of the samples.

KS

A notable triplite from Pakistan. Triplite (Mn22+[PO4]F) is a

rare mineral that forms in phosphate-rich granitic peg-matites, typically as irregular brown opaque masses.Transparent triplite is quite rare, and the material is not easyto facet due to its brittleness and cleavage. It also has ratherlow hardness for a gemstone, at 5–51/2 on the Mohs scale.

These contributors were very surprised, therefore, whena transparent, reddish orange triplite weighing 7.16 ct wasloaned to GIA for examination by Dudley Blauwet ofDudley Blauwet Gems. Mr. Blauwet stated that the roughwas mined in the Shigar Valley in northern Pakistan, about5–6 hours’ walk from the village of Alchuri. He also indi-cated that transparent crystals of a similar phosphate min-eral called väyrynenite (Mn2+Be[PO4][OH,F]) have beenfound in the same area. Attractive crystals of triplite were

Figure 21. This 6-mm-diameter sapphire shows bothan unusual “eye”—actually a near-colorless band—and a weak six-rayed star. Photo by Denis Gravier.

Figure 22. This 270 ct cat’s-eye topaz is notable for itslarge size and Ukrainian origin. Photo by M. Glas.

GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004 347

reportedly mined in the Shigar Valley in 1995, on a matrixof albite and fluorite (A. Weerth and V. M. F. Hammer,“Mineralien vom ‘Dach der Welt’: Neue Überraschungenaus dem Pamir, dem Karakoram und dem Himalaya,”Lapis, Vol. 25, No. 5, 2000, pp. 22–29). Most of this materi-al was evidently sold as mineral specimens, and only a fewsmall, dark brown triplites from Pakistan are known tohave been cut (M. Kaufman, Kaufman Enterprises, SanDiego, pers. comm., 2004).

The 7.16 ct triplite was faceted into an oval modifiedbrilliant (figure 23). The following properties wereobtained by one of us (EPQ): color—reddish orange, withweak pleochroism in reddish orange and yellowish orange;diaphaneity—transparent; R.I.—1.658–1.677; birefrin-gence—0.019; S.G.—3.87; orangy red Chelsea filter reac-tion; and inert to both long- and short-wave UV radiation.General absorption to 450 nm, weak absorption bands at470 and 490 nm, and a stronger band at 520–560 nm wereobserved with a desk-model spectroscope. Microscopicexamination revealed “fingerprints,” fractures, two-phaseinclusions, and a phantom-like growth plane.

Powder X-ray diffraction analysis by WBS and AUF wasperformed using a piece of rough from which the 7.16 ctstone was cut, and it showed a close match to the triplitereference pattern. Electron-microprobe analysis of this frag-ment yielded the following composition (average of ninespots, in wt.%): 54.91 MnO, 31.92 P2O5, 6.87 F, 4.20 CaO,3.91 FeO, 0.81 H2O (calculated), 0.06 Al2O3, and 0.06 SiO2.After subtracting 2.89 wt.% (calculated oxygen equivalentof fluorine, by weight), the total was 99.83 wt.%. The datarepresent what are close to the highest Mn and lowest Fecontents documented in the literature for triplite. By com-parison, only one of the 11 analyses reported by C. Palache

et al. (The System of Mineralogy of James Dwight Danaand Edward Salisbury Dana, Vol. 2, John Wiley and Sons,New York, 1951, pp. 849–852) has a greater Mn:Fe ratio,with 57.63 wt.% MnO and 1.68 wt.% FeO in a “salmon-pink” sample from White Pine County, Nevada.

Although the reddish orange color has not been report-ed previously for triplite, the R.I., birefringence, S.G., andchemical composition of the 7.16 ct stone are within thewide range of values given in the literature.

BML

Elizabeth P. Quinn

William “Skip” B. Simmons and Alexander U. FalsterUniversity of New Orleans, Louisiana

Update on several gem localities in Zambia and Malawi. InSeptember 2004, Gems & Gemology editor Brendan Laursvisited several gem deposits in Zambia and Malawi as partof a collaborative research project to gather first-hand infor-mation on the location, geology, and gem production ofcommercially important gem sources in southern Africa.The other collaborators were Dr. William B. “Skip”Simmons of the University of New Orleans, Louisiana; Dr.Hanco Zwaan of the National Museum of Natural History,Leiden, The Netherlands; and Bjorn Anckar of theEuropean Union’s Mining Sector Diversification Pro-gramme (MSDP) in Lusaka, Zambia. Mr. Anckar, a geolo-gist and gemologist who has lived in Zambia for the pasttwo and a half years, was our guide for much of the trip.The MSDP (www.msdp.org.zm/index.htm) is a five-yearproject supported by the European Development Fund topromote the sustainable development of the non-tradition-al mining sector in Zambia. Assisting the development ofgem mining is an important component of this program.Recently, the World Bank began working closely with theMSDP on a separate Zambian aid program called Supportfor Economic Expansion and Diversification (visit www-wds.worldbank.org/default.jsp?site=wds and browse theZambian documents). This program includes a gem com-ponent that “will support measures aiming to promotegemstones [sic] production and trade, and facilitate itsinclusion into the formal economy, improve the sector’ssocio-economic contribution at the regional and nationallevels, and encourage private sector investments.”

Our fieldwork in Zambia focused on three regions:Kafubu for emeralds, Mkushi for tourmaline and morgan-ite, and Lundazi for “Canary” tourmaline and aquamarine.In addition, we visited the Chimwadzulu Hill ruby/sap-phire deposit in Malawi.

Kafubu Emerald Region. With a reputation as the world’ssecond most important source of emeralds by value (afterColombia), this broad area near the Kafubu River containsseveral large open-pit mines (e.g., figure 24) that are beingactively mined by international companies using heavyequipment. The geology at all the mines is rather similar:

Figure 23. At 7.16 ct, this triplite from Pakistan isremarkable for its size, transparency, and attractivecolor. Courtesy of Dudley Blauwet Gems; photo byMaha Tannous.

348 GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004

Emeralds are hosted by phlogopite-biotite schist adjacent toquartz-tourmaline veins, although the mineralization isquite uneven and unpredictable. During the intrusion of theveins, hydrothermal fluids altered the talc-chlorite-amphi-bole host rocks to form a phlogopite-biotite zone within cen-timeters to meters of the vein contacts (see A. V. Seifert etal., “Emerald mineralization in the Kafubu area, Zambia,”Bulletin of Geosciences, Vol. 79, No. 1, 2004, pp. 1–40).

We visited four pits: Grizzly, Chantete, Pirala, andTwampane. The first two were being mined using largehaul trucks and excavators. The Pirala mine had recentlyreopened, with production expected to begin shortly afterour visit. Excavations to expose the vein were being donewith equipment brought in from the nearby Twampanemine, which had recently halted active mining. Thelargest mining concession in the area (consisting of several

pits) continues to be operated by Kagem Mining Ltd., andanother prominent operation, the Kamakanga mine, alsowas active. At all the big pits, the miners drill and useexplosives to open the areas adjacent to the veins (figure25), and emeralds are hand-picked from the mineralizedschist by experienced “chiselers.” One of the mining oper-ators (Kagem) currently has a small washing plant, while alarger processing plant being constructed at the Grizzlymine is projected to process 50 tonnes/hour of ore.

Although production figures for Zambian emeralds arenot generally available, the owner of the Chantete mineindicated that he produces 150–300 kg of beryl per month,but typically only 1% is gem quality. At best, 10% of thematerial can be polished into faceted stones and cabo-chons. Security remains a problem at all the mines, andwe were told that some deposits lose more than 80% oftheir production to theft. Most of Zambia’s emeralds areexported to India (for use in the domestic market) andIsrael (for international distribution).

Mkushi pegmatite region. In the mid- to late-1990s, theJagoda mine was an important producer of pink-to-redtourmaline and some morganite. The near-vertical peg-matite dike trends north-northwest and has been exploredto a depth of about 15 m in an elongate open pit. The peg-matite is geochemically quite highly evolved, being com-posed mainly of “cleavelandite” (albite), quartz, andalbitized K-feldspar with local areas of lepidolite and tour-maline. One particularly large pocket produced some enor-mous tourmaline crystals that typically showed a thinlayer of black to dark green covering a pink interior (figure26). Mine owners Claire Chan and Ross Walker, of theJagoda Gem Centre in Lusaka, have recently reactivatedthe deposit using heavy equipment. The open pit is beingenlarged so the pegmatite can be mined at deeper levels,and surrounding areas will be explored through trenching.

The Kumanga mine is another source of gem tourma-line in the Mkushi area, and has been mined by RajnishSharma (Gemstone Marketing & Consultancy Ltd.,Lusaka) since 1998. He has opened 15 pockets with tour-maline colors ranging from pink, bicolored pink-green,green, to dark blue. One portion of the pegmatite has been

Figure 25. The Chantete emerald mine in Zambiahas been worked by mechanized equipment since

2002 in an open pit up to 35 m deep. Occasionally,large emerald crystals are produced (see inset).

Photos by Brendan Laurs.

Figure 24. One of the largest emerald pits in Zambia is the Grizzly. As at other mines in the Kafubu area, theemeralds are extracted from phlogopite-biotite schist adjacent to tourmaline-quartz veins. Photo by Brendan Laurs.

GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004 349

mined in a deep trench to about 15 m, and future work willlikely concentrate on adjacent areas closer to the surface.

Lundazi pegmatite area. Numerous pegmatites containinggem-quality aquamarine, tourmaline, and spessartine occurin eastern Zambia, in a large area west and southwest ofLundazi, and east of the Luangwa River. Since the early1980s, this area has been a source of bright yellow Canarytourmaline (sometimes incorrectly reported as being fromMalawi or Mozambique; see Gem News International,Summer 2001, pp. 151–152, and Spring 2004, p. 86). Sincethe mid-1990s, commercial quantities of this bright yellowtourmaline have been recovered from primary and sec-ondary deposits in a localized area covered by two miningconcessions: Kabelubelu and Tumbuka. Since late 2002,the deposit has been leased by Tommy Wu (Shire TradingLtd., Hong Kong) and Rita Mittal (Southstream EnterprisesLtd., Lusaka). They have undertaken further exploration of

the pegmatite and also used a washing plant to process elu-vium and alluvium from several locations. At the time ofour visit, exploratory mining for dark blue (or “doubleblue”) aquamarine was occurring at a pegmatite on an adja-cent mining concession (figure 27). The aquamarine occursas fractured crystals that are frozen within the pegmatite,yielding faceted stones that are typically less than 0.5 ct butdo not require any heat treatment. In contrast, most of theCanary tourmaline is heated to 500–550°C to bring out thebright yellow color from the typically brown to greenishyellow starting material. Future work will focus on miningCanary tourmaline from secondary deposits.

Chimwadzulu Hill ruby/sapphire deposit, Malawi. Sincethe reports on Chimwadzulu Hill that were published in theSpring 2000 Gem News (pp. 71–73) and Spring 2004 GemNews International (p. 71), mine owner David Hargreaves(Minex Ltd., Surrey, United Kingdom) has continued a sys-tematic exploration program of auger holes, trenches, andpits to better define areas of ruby concentration in the eluvi-

Figure 27. In the Lundazi area of eastern Zambia, apegmatite located near the Canary tourmaline depositis explored for dark blue aquamarine. The pegmatitecan be seen as the light-colored vertical dike in thewall behind the miners. Photo by Brendan Laurs.

Figure 26. Claire Chan shows one of the large tourma-line crystals mined from Zambia’s Jagoda pegmatitein the late 1990s. The crystals from this pocket haddistinctive pyramidal terminations and the pink inte-riors were overgrown by a thin black to dark green“skin” (as seen in the inset). Photos by Brendan Laurs.

350 GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004

um. About 2,000 test holes have been sunk at 5–10 m spac-ing, to a depth of 3–4 m. The most productive level of theeluvium typically ranges from 1.0 to 1.5 m below the sur-face. Future exploration will focus on completing the pit-ting/drilling program and exploring the underlying bedrockfor in situ corundum, to help understand the mineralizationand distribution of ruby and sapphire in the eluvium. Inaddition, a new washing plant equipped with jigs and a mag-netic separator has been commissioned to help meet thedemand for rubies and “padparadscha” sapphires from thisdeposit, which do not require treatment and are being mar-keted as Nyala ruby and sapphire. Mr. Hargreaves reportedthat the new washing plant will increase the processing

capacity from 30 to 100 m3 of eluvium per day, and shouldyield about 4,500 grams of facetable corundum annually.Historically, production from the deposit has consisted ofapproximately 30% ruby and 17% “padparadscha” sapphire(figure 28), with the remainder various fancy colors (mostlyin the pink to purple range).

In this contributor’s opinion, the gem areas describedabove show significant future potential. The Kafubu emer-ald area, in particular, is far from exhausted and could ben-efit from more systematic prospecting and the introduc-tion of a modern washing plant. Zambia’s pegmatite dis-tricts also show potential, although additional discoverieswill depend on securing the necessary capital for furtherexploration and mining, as well as locating buried primaryand eluvial deposits in the deeply weathered and poorlyexposed near-surface horizon. The Chimwadzulu Hilldeposit seems poised for a major expansion, in light of theadvanced exploration program and modernized washingplant that was recently installed. Additional developmentsand further details on these deposits will be reported infuture articles that are being prepared for submission toGems & Gemology.

BML

INCLUSIONS IN GEMSBarite “spears” in fluorite. At a recent street fair inCarlsbad, California, GIA director of gem identificationShane McClure discovered a tray of freeform polishedpieces of bicolored purple and green fluorite. Although nolocality was given by the vendor, their coloration resem-bled that of some fluorite from Hunan Province, China.

Upon closer inspection, he found a 261.47 ct specimen(48.2 × 38.6 × 10.9 mm) that appeared to contain whitespear-shaped inclusions of some unknown mineral (figure

Figure 29. This 261.47 ct bicolored green and purplefluorite held an interesting suite of white spear-shaped inclusions. Photo by Maha Tannous.

Figure 30. Raman analysis was used to identify thespear-shaped inclusions in the bi-colored fluoriteas barite. Photomicrograph by John I. Koivula;magnified 10×.

Figure 28. Mine manager Hilton Cook examines aruby that was recovered in late September 2004 atChimwadzulu Hill, Malawi. Photo by W. B. Simmons.The inset shows a 0.80 ct “padparadscha” sapphirefrom this deposit; courtesy of Columbia Gem House,Vancouver, Washington.

29). Since this was the only piece that contained theseinclusions, and since solid inclusions of this shape havenot been reported previously in fluorite, Mr. McClure pur-chased the stone for examination in the laboratory.

Microscopic examination showed that all the inclu-sions had a pointed, spear-like bladed habit; most wereopaque white (figure 30). However, a few were transparent,and cross-polarized light showed them to be birefringent.One of the inclusions reached a polished surface, providingan ideal opportunity for Raman analysis, which served toidentify the inclusion as barite.

Barite has been noted before as spherical inclusions influorite from Illinois (see J. I. Koivula and S. Elen, “Barite

inclusions in fluorite,” Winter 1998 Gems & Gemology, pp.281–283), but never in this pointed habit. Interestingly, thespear-like shape of these barite inclusions looks quite simi-lar to a primary fluid inclusion in a fluorite from Illinoisreported by E. J. Gübelin and J. I. Koivula (Photoatlas ofInclusions in Gemstones, ABC Edition, Zurich, 1986, p. 83).

John I. Koivula ([email protected])and Maha Tannous

Arizona peridot with unusual inclusions. AlexandreWolkonsky, a lapidary in Saint Cloud, near Paris, France,brought a remarkable peridot from San Carlos, Arizona(figure 31) to our attention. The 6.97 ct chevron-hexagoncut stone measured approximately 11.7 mm across andabout 7.6 mm deep. The gem’s identity was confirmed byR.I.’s of 1.650–1.688, a birefringence of 0.038, a biaxial pos-itive optic character, and an S.G. of 3.35, all typical valuesfor peridot.

The stone displayed several unusual white surface-reaching inclusions on its table. These had wedge- or dag-ger-like shapes plunging into the stone. They were allessentially parallel to one another, suggesting a relationshipto crystallographic orientation (figure 32). Their intersec-tion with the surface was also roughly parallel, althoughmore irregular (figure 33), and never exceeded 0.05 mmwide. The overall shape and orientation of these inclusionssuggested that they might be etched dislocations, as seen inspodumene, diamond, and many other gems.

What was unusual about these features was that theywere filled with a white substance that Mr. Wolkonsky ini-tially believed was glue added to reinforce the stone.However, close inspection revealed that it was a granular,somewhat glistening powder-like material, easily scratchedaway. Qualitative microanalysis of the inclusions obtained

Figure 31. This 6.97 ct Arizona peridot contains unusu-al aligned surface-reaching inclusions reminiscent ofetched dislocations. Courtesy of A. Wolkonsky; photoby Alain Cossard.

GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004 351

Figure 32. The inclusions in the Arizona peridot weregrouped essentially parallel to one another, possiblydue to crystallographic orientation. Photomicrographby E. Fritsch; magnified 2×.

Figure 33. With higher magnification, the slightly irreg-ular shape of the inclusions’ intersections with thetable facet is visible. Note also the somewhat reflectiveappearance of the filling material in the inclusions.Photomicrograph by E. Fritsch, magnified 9×.

352 GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004

using a Jeol 5800 scanning electron microscope equippedwith a PGT energy-dispersive X-ray detector revealed mag-nesium, silicon, oxygen, and traces of iron, with Mg>Si buta variable Mg/Si ratio (the analyzed volume did not includethe peridot matrix). No useful signal was obtained byRaman analysis, probably because of the very reflectivenature of the material. We surmise that the included mate-rial might be a hydrated alteration product of peridot, suchas some variety of fine-grained serpentine.

EF

Y. LulzacCRG, Nantes, France

Double-eye chatoyant quartz. Cat’s-eye gems characteristi-cally show a chatoyant band of reflected light oriented per-pendicular to the phenomenon-causing inclusions, whichare commonly thin hollow tubes resulting from growthblockage (growth tubes) and/or post-growth dissolution fea-tures (etch tubes). In either case, the cat’s-eye appears as asingle band of reflected light when illuminated from abovewith a single beam of light. If a chatoyant gem is examinedunder two light sources simultaneously, then two chatoy-ant bands will be visible. Virtually all chatoyant gems dis-play their cat’s-eye phenomenon in such a manner.

However, a most unusual 11.94 ct cabochon of cat’s-eye rock crystal quartz was recently acquired by ElaineRohrbach of Gem Fare in Pittstown, New Jersey, while ona buying trip to Brazil. What made this gem intriguing wasthat it displayed two near-parallel chatoyant bands of vir-tually equal strength when illuminated with only a singlelight source (figure 34).

Since a few of the chatoyancy-causing inclusions wererelatively large, it was possible to determine by microscop-ic examination that at least the larger tubes resulted frometching, and that some contained an epigenetic iron-stained residue (figure 35). The size of the largest inclusionsalso made it possible to see what caused two chatoyantbands to appear from a single light source. The etch tubes,

which were all oriented in the same direction, were sharplyangular down their length and also very mirror-like in theirreflectance. This angularity caused incident light to bereflected simultaneously in two directions, which resultedin two chatoyant bands instead of just one.

John I. Koivula and Maha Tannous

Graphite inclusions in quartz from Brazil. “Graphite” hasbeen mentioned many times as an inclusion in quartz, butuntil now these specimens have proved to contain onlyamorphous hydrocarbons, sometimes referred to as“anthraxolite” or “asphaltite” (see Spring 2004 Gem NewsInternational, pp. 79–81). The most famous examples ofhydrocarbon-included quartz are the splendid groups ofdoubly terminated “Herkimer” rock crystals fromMiddleville, Herkimer County, New York, which origi-nate in silicified dolomites. Similar geoenvironments have

Figure 36. Quartz crystals with cylindrical graphiteinclusions, such as this 5.2-cm-wide intergrown crys-tal, have recently come on the market, reportedlyfrom Bahia, Brazil. Photo by J. Hyrsl.

Figure 34. This unusual 11.94 ct cabochon of rockcrystal quartz shows two strong chatoyant bandsunder a single light source. Courtesy of ElaineRohrbach; photo by Maha Tannous.

Figure 35. The complex angular shape of the etchtubes in the cat’s-eye quartz causes light to be reflect-ed simultaneously in two directions, forming twochatoyant bands instead of one. Photomicrograph byJohn I. Koivula; magnified 10×.

produced such quartz crystals all over the world, withplentiful deposits recently found in Sichuan Province,China (B. Ottens, Ed., China—extraLapis No. 26/27,Christian Weise Verlag, Munich, Germany, 2004,198 pp.).In such specimens, the black anthraxolite has an irregularform, although very rarely it is present as phantoms insome of the crystals from China.

Recently, this contributor encountered quartz crystalscontaining some unusually lustrous graphite inclusions(figure 36). They reportedly came from the state of Bahia,Brazil, although the exact locality is still unknown. Thecrystals were doubly terminated and typically up to about3 cm long, although exceptional examples reached nearly10 cm. The graphite inclusions formed cylinders up to 3cm long and 3 mm wide (rarely, they were botryoidal).Almost all the graphite cylinders viewed by this contribu-tor were broken at both ends; only very rarely did theyshow a hemisphere-shaped termination on one end. Whenthe cylinders were viewed down their long axis, a radiatingfibrous structure was quite visible in some cases. Theidentification of the inclusions as graphite was establishedby X-ray powder diffraction analysis. Some of the expectedX-ray lines were missing, and this may be due to the for-mation of the graphite from the metamorphosis of theamorphous hydrocarbons. It is common for quartz crystalscontaining hydrocarbons to form during the lithification ofsediments (i.e., diagenesis); subsequent higher grade meta-morphism could cause these inclusions to recrystallizeinto graphite by driving off the volatiles (hydrogen andoxygen) from the hydrocarbons.

The graphite cylinders were in most cases completelyenclosed by the quartz and therefore quite pristine. Onlyin specimens where the cylinders reached the surface wasthe graphite replaced by yellow-brown iron oxides or(rarely) absent, leaving a hollow cavity. Because many ofthe host quartz crystals are quite transparent, they can befaceted into very interesting cut stones (figure 37).

Jaroslav Hyrsl ([email protected])Kolin, Czech Republic

Quartz with molybdenite. A recent discovery of trans-parent rock crystal in Chile has provided those interest-ed in inclusions with some very unusual specimens.The well-formed crystals are singly or doubly terminat-ed, with the doubly terminated specimens being lessprevalent, as would be expected. Crystals weighing over10 kg have been recovered from this locality, which isreported as the Confianza mine, Tilama, Valparaíso.Four gem-quality crystals were provided to these con-tributors by well-known mineral collectors and dealersRussell E. Behnke of Meriden, Connecticut, and WilliamW. Pinch of Pittsford, New York. As shown in figure 38,the largest of the four weighed 378.73 ct and measured42.8 × 40.9 × 37.6 mm.

The highlight of this discovery was that the quartz crys-tals contained phantoms decorated or dusted with thin

platy crystals or crystal clusters of molybdenite (MoS2),which was identified by EDXRF and X-ray diffraction analy-sis. Some of these inclusions were very well-formed andshowed distinct surface growth features as well as theexpected lead-gray metallic luster of molybdenite (figure 39).

John I. Koivula and Maha Tannous

Rutile “moth” in quartz. Rutile is a relatively commoninclusion in quartz. However, fine examples showing well-developed six-rayed stars, four-rayed crosses, or beautifulsagenitic patterns are rare (see, e.g., Summer 2001 GemNews International, p. 146). Recently we had the opportu-nity to examine an interesting 13.97 ct rutilated quartz

Figure 38. These Chilean quartz crystals containphantoms formed by molybdenite inclusions. Thelargest crystal weighs 378.73 ct, while the longest onemeasures 65.8 mm. Courtesy of Russell E. Behnkeand William W. Pinch; photo by Maha Tannous.

Figure 37. This 117.10 ct faceted quartz contains inclu-sions of well-formed graphite cylinders. Photo by J. Hyrsl.

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from the Golconda mine, Minas Gerais, Brazil, which wasprovided by Luciana Barbosa of the Gemological Center inBelo Horizonte. Prominently displayed under the tablefacet was a most unusual rutile inclusion pattern.

The inclusion formation consisted of numerous dense-ly packed parallel light yellowish brown needles of rutilethat were swept back at an angle from a central opaque sil-very black inclusion of hematite. The plane of this inclu-sion combination was oriented just slightly off-parallel tothe plane of the table facet. As shown in figure 40, this ori-entation allowed the inclusion pattern to reflect lightwithout interference from any reflection off the table facet.The precise epitaxial growth of rutile needles from thehematite, together with their dense, parallel formation and

simultaneous reflectance, created the appearance of mothwings, while the contrasting black hematite formed theinsect’s “body” (figure 41). Through the years we haveexamined many fine examples of rutilated quartz. This isthe first such hematite-rutile “moth” pattern we haveencountered, so in our estimation this stone is not justunusual, it is unique.

John I. Koivula and Maha Tannous

SYNTHETICS AND SIMULANTSSynthetic Verneuil corundum with unusual color zoning.During a trip to Sri Lanka in mid-2004, one of our clientspurchased, among other faceted corundums, a red 1.05 ctmodified round brilliant with unusual color zoning.Refractive indices of 1.760–1.770 and a hydrostatic S.G. of4.00 confirmed that it was corundum.

Viewed face-up, the sample appeared uniformly pur-plish red (figure 42, left). From the side, however, itappeared very light blue in the crown portion, while theculet area was purplish red (figure 42, right). Such colorzoning has been observed in various colors of sapphirefrom Songea (Tanzania) and Sri Lanka, especially in blueand orange stones. A strong red fluorescence to long-waveUV radiation was observed in the culet area, and Ramanspectroscopy confirmed that both parts were corundum.

With magnification, it became obvious that this was aVerneuil (flame fusion) synthetic sapphire, as numerousgas bubbles were visible in the very light blue portion (fig-ure 43). When immersed in methylene iodide, the bound-

Figure 40. Oriented rutile needles extending from theedges of a hematite plate form an unusual moth-shapedinclusion in this 13.97 ct rock crystal from Brazil.Courtesy of Luciana Barbosa; photo by Maha Tannous.

Figure 41. The orientation of the rutile inclusions,together with their dense, parallel formation andsimultaneous reflectance create the appearance ofmoth wings, while the contrasting black hematiteforms the “body.” Photomicrograph by John I.Koivula; magnified 10×.

Figure 39. The molybdenite inclusions in the Chileanquartz display a characteristic lead-gray color andplaty hexagonal form. Photomicrograph by John I.Koivula; magnified 10×.

ary between the purplish red and very light blue zonesappeared curved (figure 44). However, no curved striaewere observed in the purplish red portion. A qualitativechemical analysis of the table facet by EDXRF showedonly Al; no Ga was detected, as expected for a flame-fusionsynthetic corundum.

These observations indicated that the sample was cutfrom a color-zoned boule of Verneuil synthetic corundum,with the purplish red part representing the small center ofthe otherwise very light blue boule. This also explained thelarge fissures observed perpendicular to the growth direc-tion (again, see figure 44). Verneuil boules usually havesome tension along their growth axis along which they aresplit before being cut. Obviously this was not done in thiscase, and therefore the tension cracks developed.

Lore Kiefert ([email protected])SSEF Swiss Gemmological Institute, Basel

HAH

KS

Imitation clam “pearl.” Throughout history, shell materi-al has often been fashioned to resemble true pearls andnon-nacreous “pearls,” sometimes for the purpose ofdeceiving the consumer. The West Coast laboratory, forexample, recently inspected several specimens of conchshell that were carefully and convincingly fashioned tomimic conch “pearls.” Even more recently, this contribu-tor examined an item that at first appeared like a naturalpearl-like calcareous concretion (figure 45). It was donatedto GIA by Bill Larson of Pala International, Fallbrook,California, who had obtained it at a jewelry store in LaPaz, Baja California, Mexico. The store had about a dozenof these samples, which were represented to Mr. Larson as“genuine clam pearls” that had been polished. However,

Figure 44. With immersion, the curved growth bound-ary in this synthetic corundum (4.7 mm from table toculet) is clearly visible. The gray area at the top of theimage is a tension crack. Such fractures are character-istically oriented perpendicular to the growth axis ofthe boule. Photomicrograph by H. A. Hänni, © SSEF.

Figure 45. This imitation clam “pearl” (17.5 × 10.8 ×10.2 mm) proved to be polished shell material froman unknown mollusk. Photo by Maha Tannous.

Figure 43. Gas bubbles appear to be radiating fromthe center of the color-zoned synthetic corundum(5.0–5.2 mm in diameter). Photomicrograph by H. A. Hänni, © SSEF.

Figure 42. This 1.05 ct synthetic corundum appearsuniformly purplish red when viewed face-up (left),while the color zoning is clearly visible from the side(right). Composite photo by H. A. Hänni, © SSEF.

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356 GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004

he suspected that they were imitations, and purchased onesample for closer examination.

The 15.31 ct semitranslucent ovoid specimen was purewhite, with a very uniform appearance and shiny, porcela-neous luster. With low magnification, its true nature wasevident: The absence of nacre confirmed that the item wasnot a pearl, and transmitted fiber-optic illuminationrevealed a prominent parallel banded structure, immedi-ately identifying the sample as shell material rather thanany type of pearl-like concretion (figure 46, left). Mostinteresting was the coarse to fine flame-like structure ori-ented perpendicular to the banding (figure 46, right).

The refractometer showed a cutoff at approximately1.65 with a birefringence blink; the lower value was notdistinguishable. The S.G. (determined hydrostatically)was roughly 2.76. Long-wave UV fluorescence was weakto moderate chalky yellowish white with very weak lightbrown streaks corresponding to the structural banding;short-wave UV fluorescence was similar, but even weak-er. No distinguishing spectrum was seen with the desk-model spectroscope.

“Flame” structure is commonly found in porcelaneousnon-nacreous “pearls” from some mollusks such as theconch, giant clam (Tridacna gigas), and Pacific Oceanthorny oyster (Spondylus calcifer carpenter; see Winter1987 Lab Notes, p. 235); the latter is found in the Gulf ofCalifornia. The flame structure in this imitation clam“pearl” may have fooled an unwary buyer into believingthat it was a pearl-like concretion, rather than shaped andpolished shell material. However, as this example shows,flame structure also may be seen in the shell of these andsimilar mollusks. Although it would have been interestingto identify the specific type of mollusk from which thisshell material originated, this was not possible because wedid not have access to the shells needed for comparison.

Cheryl Y. Wentzell ([email protected])GIA Gem Laboratory, Carlsbad

ANNOUNCEMENTSVisit Gems & Gemology in Tucson. Meet the editors andtake advantage of special offers on subscriptions and backissues at the G&G booth in the Galleria section (middle

floor) of the Tucson Convention Center during the AGTAshow, February 2–7, 2005.

GIA Education’s traveling Extension classes will offerhands-on training in Tucson with “Gem Identification”(January 31–February 4) and “Advanced Gemology”(February 5). To enroll, call 800-421-7250, ext. 4001.Outside the U.S. and Canada, call 760-603-4001.

The GIA Alumni Association will host a Dance Partyin Tucson on February 5, featuring a silent auction, anindustry awards presentation, and a live auction. To reservetickets, call 760-603-4204 or e-mail [email protected].

Gem treatment seminar in Tucson. An update on thetreatment of corundum and other gem materials will bepresented by Ted Themelis during the Tucson gemshows on February 3, 2005 at the Marriot UniversityPark Hotel. Among the subjects covered will be laser-induced breakdown spectroscopy (LIBS) and new treat-ment methods in Sri Lanka and India. Prior reservation isrequired; contact [email protected] or visitwww.themelis.com/Tucson2005.

2005 Gem-A field trips. The Gemmological Associationof Great Britain is planning two field trips for 2005, a visitto Idar-Oberstein, Germany, March 13–19, and a tour ofMinas Gerais State, Brazil, August 15–29. Both field tripswill visit local cutting centers and gem mines. [email protected] or visit www.gem-a.info/membership/fieldTrips.htm.

ExhibitsCartier Collection in Houston. “Cartier Design Viewed byEttore Sottsass,” an exhibition of over 200 objects from theCartier Collection, will be on display at the Museum ofFine Arts, Houston, through March 27, 2005. Among thepieces displayed are diadems, brooches, and rings, as wellas jeweled accessories such as cigarette cases, clocks, andwatches. E-mail [email protected] or visitwww.mfah.org.

Native American Jewelry at AMNH. “From Totems toTurquoise: Native North America Jewelry Arts of the

Figure 46. With transmitted light,the imitation “pearl” shown infigure 45 displayed banding (left)and “flame” structures (right).Note also the fine lamellar struc-ture of the banding that is nearlyperpendicular to the flame-likestructure. Photomicrographs by Maha Tannous (left, magnified 10×) and John I.Koivula (right, magnified 15×)

GEM NEWS INTERNATIONAL GEMS & GEMOLOGY WINTER 2004 357

Northwest and Southwest,” an exhibition of more than500 pieces of contemporary and historic Native Americanjewelry, is being held at the American Museum of NaturalHistory in New York City until July 10, 2005. Visitwww.amnh.org/exhibitions/totems/ or call 212-769-5100.

ConferencesWJA in New York. The Women’s Jewelry Association“Women In the Know” business conference will be heldon Friday, March 4, at the Fashion Institute of Technologyin New York City. Topics will include leadership develop-ment, Internet business strategy, and customer servicemanagement. Visit www.womensjewelry.org or call 310-937-8997.

PDAC 2005. The Prospectors and Developers Association ofCanada convention will take place March 6–9 in Toronto.Diamonds will be featured in a session called “Diamonds—Around the World in 120 Minutes,” and also will be includ-ed in other sessions. Visit www.pdac.ca/pdac/conv.

BaselWorld 2005. The BaselWorld show will be heldMarch 31–April 7 in Basel, Switzerland. GIA will hostGemFest Basel on April 2, 4–6 pm, at the BaselConvention Center, Hall Montreal. The program will befollowed by a reception. During the show, Gems &Gemology editor-in-chief Alice Keller will be available atthe GIA Booth in Hall 2, Stand W23. For more informationon BaselWorld, visit www.baselshow.com, call 800-922-7359, or e-mail [email protected].

Russian gemology. A session on gemology will be heldduring VII International Conference: New Ideas in EarthScience at the Moscow State Geological ProspectingUniversity April 5–6, 2005. E-mail [email protected].

GemmoBasel 2005. The first open gemological conferencein Switzerland will be presented by the SSEF SwissGemmological Institute at the University of Basel, April29–May 2, 2005. Among the events scheduled is a fieldtrip to a Swiss manufacturer of synthetic corundum andcubic zirconia. Visit http://www.gemmobasel2005.org orcontact [email protected].

ICNDST-10 in Japan. The 10th International Conferenceof New Diamond Science and Technology will be held atthe National Institute of Advanced Industrial Science andTechnology Conference Hall in Tsukuba, Japan, May11–14, 2005. Among the topics covered will be HPHT syn-thesis and processing and the growth of CVD syntheticdiamond. Visit www2.convention.co.jp/ICNDST-10 oremail [email protected].

Diamonds at GAC-MAC. The 2005 joint meeting of theGeological Association of Canada and the Mineralogical

Association of Canada will be held May 15–18, 2005, inHalifax, Nova Scotia. “From Cratons to Carats: A sympo-sium to honour the career of Herwart Helmstaedt” willfeature presentations on geotectonic controls on dia-mond exploration. E-mail [email protected] or visitwww.halifax2005.ca.

Bead Expo in Miami. The 2005 International Bead Expowill be held in Miami, Florida, May 18–22. Over 60 work-shops and educational lectures on bead jewelry design andmanufacture are scheduled. E-mail [email protected] orvisit www.beadexpo.com.

Goldschmidt Conference. The 15th Annual GoldschmidtConference will take place May 20–25, 2005, in Moscow,Idaho. The meeting will include a session on the geochem-istry of gem deposits, and also will include numerous pre-sentations on advanced analytical techniques. [email protected] or visit www.uidaho.edu/gold2005.

ERRATA1. The Winter 2003 Gem News International entry,

“Some interesting pearls from the North AmericanWest Coast” (pp. 332–333), may have given theimpression that the green abalone (Haliotis fulgens)and the pink abalone (H. corrugata) can be legallyfished in the United States. In fact, both commercialand sport fishing of these particular species have beenbanned in the U.S. since 1996 (limited sport fishing forred abalone is allowed under strict regulations). Thenear-round abalone pearl described in this entry wasrecovered from a green abalone in waters off the coastof Mexico; the abalone pearl with the unusual growthstructure was from a red abalone and purchased froman old collection.

2. Since the publication of the Summer 2004 Gem NewsInternational entry, “‘Shell pearls’ with Tridacna clamshell beads” (p. 178), it has come to our attention thatTridacna giant clams are protected under theConvention on International Trade in EndangeredSpecies of Wild Fauna and Flora (CITES), Appendix II(www.cites.org/eng/append/appendices.shtml).Materials listed in CITES Appendix II may not beexported without a license, and listed marine materialsrecovered from international waters may not be import-ed into the United States without a permit from theU.S. Fish and Wildlife Service. Those contemplatinginternational trade in any cultured or imitation pearlsusing Tridacna nuclei should take care to comply withpermitting regulations; however, as noted in the entry,the use of Tridacna shell as pearl nuclei is a practicebest avoided (see also Summer 2002 Gem NewsInternational, p. 179).

BOOK REVIEWS GEMS & GEMOLOGY WINTER 2004 359

Bernd Munsteiner: Reflexionenin Stein [Reflections in Stone]Edited by Wilhelm Lindemann, 224pp., illus., publ. by Arnoldsche,Stuttgart, Germany, 2004 (inGerman and English). US$75.00*

This extraordinary new book on BerndMunsteiner sets the famous lapidarist’swork firmly within the realm of art—showing it to us not as we are accus-tomed to seeing it, as the stonecutter’scraft taken to the edge of possibility,but as something more. In the complexargument that opens the book, Linde-mann explains how the development offaceting during the Renaissance tookcutters away from the ancient view ofprecious stones as earthbound sourcesof divine light: In other words, even asgems grew more sparkly, their beautylost its connection to the underlyingmaterial. But it is in such dynamicspaces that art flourishes. Much asCubism bridges two- and three-dimen-sional representation, the reconciliationof the tensions between crystal andlight through cutting is, in Linde-mann’s view, the driving force behindMunsteiner’s creativity. A series ofessays from American collectors Si andAnn Frazier and Michael M. Scott,German jeweler Deborah Aquado, andart historian Christianne Weber-Stoberextend this thesis and offer personalglimpses of both the man and his work.

The heart of the book, though, isits more than 200 breathtaking pho-tographs, most of them taken byJürgen Cullmann and Harold and EricaVan Pelt. Pieces are grouped themati-cally and “hung” on the white space ofthe pages as if on a gallery wall, inter-spersed with close-ups of the rutileinclusions in the “Metamorphosis”crystal and of gem minerals in various

stages of cutting. Loose gems and jew-elry from the earlier agate series arefeatured, as well as the more familiar“fantasy cut” tourmalines, aqua-marines, and quartzes. Also seen arethe sculptural works, outdoor installa-tions, and several pieces of glassworkdone for ceramics manufacturer RoyalCopenhagen. A special section isdevoted to “Dom Pedro,” the 10,000 ctaquamarine Munsteiner cut in 1993.

For both the serious collector andthe jeweler/gemologist, this bookoffers a comprehensive guide to oneof the most important lapidary artistsin the world. I particularly enjoyedseeing Munsteiner’s complete bodyof work treated as a retrospective. Asa museumgoer, I found that thisapproach helped me understand thewhole as well as revel in the parts.And as someone who had understoodthese works primarily as exercises in“gee-whiz” lapidary technique, theirintellectualism was as much of a sur-prise as their sensuality.

Beyond its obvious value as a ref-erence, Reflexionen in Stein success-fully accomplishes its goals: It carvesout a space for Bernd Munsteiner’swork within the broader context ofWestern art history—and then cele-brates what happens there, even asthe work itself invites us to do.

LISA SCHOENINGGemological Institute of America

Los Angeles

Illustrated Guide to JewelryAppraising, 3rd EditionBy Anna Miller, 200 pp., illus., publ.by GemStone Press, Woodstock, VT,2004. US$39.99*

With this edition, the late Anna Miller

updated and expanded her respectedIllustrated Guide to Jewelry Appraising.Every evaluator, whether newly mint-ed or a seasoned professional, will findit a valuable resource.

The book covers a wide range ofimportant topics, beginning with theappraiser’s role and responsibilities inthe first chapter. The second dealswith understanding the different valu-ation methods, researching pricepoints, and making the proper identi-fication. Readers will find the thirdchapter especially rich in jewelry“forensic” identification. The processof estimating values for every con-ceivable form of wearable jewelry iscovered next, while chapter 5 reviewsthe appraisal as a legal document. Thebook closes with tips on identifyingand valuing unfamiliar pieces.

The Illustrated Guide discussesjust about every major aspect of a care-fully crafted and accurate appraisal forantique, period, and modern jewelry.It is organized logically and is refresh-ingly easy to read. Miller found ampleroom for detail, but did not overdo it.This edition includes an updated list-ing of market information and priceguides, an additional jewelry period(“Consumerism,” 1990–2002), and anew chapter called “Valuing the Un-familiar,” which covers reproduction,Asian antique, and Berber jewelry.

Although the quality and value ofthe text is as expected from someonewith decades of experience, it is unfor-tunate that both the paper quality and

2004Book REVIEWS

EDITORSSusan B. JohnsonJana E. Miyahira-SmithStuart Overlin

*This book is available for purchasethrough the GIA Bookstore, 5345Armada Drive, Carlsbad, CA 92008.Telephone: (800) 421-7250, ext.4200; outside the U.S. (760) 603-4200. Fax: (760) 603-4266.

360 BOOK REVIEWS GEMS & GEMOLOGY WINTER 2004

the photographs are not up to thesame standard. After reading the first-rate text, it is disappointing to be letdown by dark, murky, and sometimesout-of-focus photographs.

In this reviewer’s opinion, thisbook is a great reference guide, but itwould have been outstanding if theproduction issues had been resolved.Nevertheless, Anna Miller has provid-ed another useful tool that would cer-tainly add value to any appraiser’slibrary.

M. ADAM NAMEROWChippewa Lake, Ohio

Magic World: Inclusions in QuartzBy Jaroslav Hyrsl and GerhardNiedermayr, 240 pp., illus., publ. byBode Verlag, Haltern, Germany,2003 [German and English]. € 49.00

This attractive book offers a fascinat-ing look into a truly magical world: theapproximately 130 minerals that havebeen documented as visible inclusionsin crystalline quartz. The objectives ofthis book are not only to describe theminerals known to occur in quartz,but also to help gemologists identifythem and encourage more collectors tostudy them. To meet these objectives,the authors have provided some 290photos and photomicrographs.

The book begins with a generaldiscussion of quartz, its modes of for-mation, and the kinds of inclusionsthat these differing modes produce.The paragenesis of fluid and solidinclusions is described, as well aswhat the presence of these inclusionstells us about the growth environ-ment. Highlights of this section arephotos of specimens and originallabels from the W. E. Hidden collec-tion, which is now housed in theNatural History Museum of Vienna.

The next eight chapters cover theinclusions themselves, organizedaccording to their chemical classifica-tion (oxides, carbonates, silicates,etc.); the last chapter is devoted toinclusions in synthetic quartz. Short

descriptions of the inclusions aregiven, along with locality and otherinformation that collectors might findvaluable. Some of these, such as dia-mond as an inclusion in quartz, arestated to have been reported but notactually verified.

Notables such as Rock Currier, Siand Ann Frazier, and John Koivulacontributed to this book. The speci-mens, superbly photographed by theauthors and others (including WernerLieber, Olaf Medenbach, and JeffScovil) capture outstanding examplesof the varied and often breathtakinglybeautiful inclusion scenes in quartzfrom a number of prominent collec-tors and institutions. These include:a 1 cm cinnabar crystal in doubly ter-minated quartz from Guizhou, China(p. 55); a 1.2 cm spray of pääkkönen-ite needles from the Cryo-genie minein California (p. 67); a large rock crys-tal quartz with actinolite needlesfrom Switzerland (p. 164); a scepter-growth quartz, also from Switzerland(p. 168); and a Japan-law quartz twinwith andradite from Peru (p. 196).

Only a few minor criticisms can bemade. In some places, the English texthas misspelled words or confusing syn-tax, such as “about 1 cm big, nicelyformed cinnabar.” Does this mean thecinnabar is 1 cm in size or that 1 cm isconsidered big for a well-formedcinnabar inclusion? (I favor the latter.)Sometimes the locality informationgiven for the photos and the names ofthe minerals listed in the index are nottranslated into English. In addition, thetext assumes an audience versed inbasic mineralogy, which might forcethe novice reader to consult other textsfor technical definitions and furtherdata on the minerals themselves.

Still, this is the best new book onmineral collecting I’ve seen in a longtime, and it is certainly the finest yeton inclusions in quartz. I hope theauthors’ aim, that many collectorswill be attracted to quartz inclusions,will become a reality, just as long asthere are still some left for me.

MICHAEL EVANSGemological Institute of America

Carlsbad, California

Minerals: Their Constitution and OriginBy Hans-Rudolf Wenk and AndreiBulakh, 668 pp., illus., publ. byCambridge University Press,Cambridge, United Kingdom, 2004.US$130.00 (hardcover); US$70.00(softbound).

This is an introductory college-levelmineralogy textbook. As such, it maynot seem a natural for the library of agemologist; yet a basic knowledge ofmodern mineralogical principles andmethods can be a tremendous advan-tage in understanding the latestadvances in gemology. Such knowl-edge can also lead to a broader appreci-ation of the properties of gemstonesand of the occurrence of gem materialsin the context of natural processes.The gemologist stands to gain greatlyfrom expanding his or her mineralogi-cal background. This book may not bethe perfect mineralogical primer for agemologist, but it has much to offer.

Minerals: Their Constitution andOrigin covers a very broad range oftopics, and does so clearly and suc-cinctly. It doesn’t delve into any topicin great depth, but it provides a goodunderstanding of those it addresses.The diagrams and photographs arewell chosen and a great help,although it should be noted thatmany of the topics assume a basicbackground in physics, chemistry,and/or mathematics.

Those topics that would probablybe of greatest interest to the gemolo-gist include crystal morphology, crys-tal growth, optical properties, color,spectroscopic techniques, mineralidentification, and mineral formation.Besides having a chapter devoted tomineral genesis, the book also coversspecific types of mineral deposits inthe context of the various mineralgroups.

The last part of the book dealswith applied mineralogy and includesa chapter on gems, both natural andsynthetic. While the coverage of gem-stones is very cursory, it is interestingto see how they are viewed in a min-eralogical context.

2004 MANUSCRIPT REVIEWERS

GEMS & GEMOLOGY requires that all articles undergo a peer review process in which each manuscript is evaluated by at leastthree experts in the field. This process is vital to the accuracy and readability of the published article, but it is also time con-suming for the reviewer. Because members of our Editorial Review Board cannot have expertise in every area, we some-times call on others in our community to share their intellect and insight. In addition to the members of our Editorial ReviewBoard, we extend a heartfelt thanks to the following individuals who reviewed manuscripts for G&G in 2004:

Mr. George BosshartDr. Jim ButlerMr. Paul CoryDr. Janet DouglasMr. Si FrazierMrs. Ann FrazierMs. Cecilia Gardner, Esq.

Dr. Gaston GiulianiMr. Mike GrayMr. Mark GronlundMr. Eli HaasDr. George HarlowMr. Hertz HasenfeldMs. Bev Hori

Dr. Jaroslav HyrslDr. Chankon KimDr. Peter LeavensDr. Robert MasonMr. Mark MaxwellMr. Sofus MichelsenMr. Roland Naftule

Mr. Franck NotariDr. Ilene ReinitzMr. Russell ShorMr. Yasukazu SuwaMr. Jack TownsendDr. Wuyi WangDr. Chris Welbourn

BOOK REVIEWS GEMS & GEMOLOGY WINTER 2004 361

In my opinion, one of the bestbooks ever written on minerals wasJohn Sinkankas’ Mineralogy forAmateurs (called simply Mineralogy inlater editions). No other book I haveseen does a better job of explainingbasic mineralogical concepts so thatvirtually anyone can understand them.Unfortunately, with the rapid advancesin modern scientific mineralogy, thisand other classic books for the layper-son have become quite dated. Minerals:Their Constitution and Origin pro-vides an excellent contemporary intro-duction to mineralogy. It may not be asenjoyable a read as some of the non-technical mineral texts available, but ifyou make the effort, you will comeaway with a lot of good, up-to-datemineralogical insight.

ANTHONY R. KAMPFNatural History Museum of Los

Angeles CountyLos Angeles, California

Rocks Pebbles and Stones:Confessions of a Private JewelerBy Fred Feldmesser, 100 pp., publ.by Farrington Press, Boston, 2004.US$30.00 (E-mail: [email protected])

It’s not often that total strangers wel-come you to share in the most per-

sonal milestones of their lives.Jewelers are not only allowed, butalso trusted, to help guide and be apart of the special moments in life:engagements, weddings, anniver-saries, and so forth. Jewelers sell dia-monds and gems, love and romance,and for this receive payment. In astyle resembling a personal journal,private jeweler Fred Feldmessershows that there are definitely morethan monetary rewards to be gained.For all the books available on everyaspect of the gem and jewelry indus-try, it is rare to come upon one suchas this. Mr. Feldmesser opens up tothe reader and relates how his love ofjewelry has led him on a journey tointeract with people and gems, aswell as the life lessons he has learned.

Rocks Pebbles and Stones: Con-fessions of a Private Jeweler is com-posed of 20 vignettes spread over 100pages in a magnificently bound vol-ume. Each essay shares a keymoment in Mr. Feldmesser’s distin-guished 30-plus-year career, or aninsight he has gained. He beginswith his father’s guidance in intro-ducing him to the world of dia-monds, gemstones, and New YorkCity’s 47th Street. He then proceedswith his visits to exotic corners ofthe world, the inner sanctums ofprestigious jewelers, and the homesof prominent clients, as well as his

charitable endeavors with BostonChildren’s Hospital. (A portion of thebook’s proceeds will go to children’shospitals in Boston and New York.)The reader will learn why Mr.Feldmesser has such an impassionedview of the role of a jeweler in peo-ple’s lives.

One of the most charming essays,“Two Small Stones,” begins in Mr.Feldmesser’s home, where a clienthas stopped by with her two youngboys to consult about some jewelry.As they leave, Mr. Feldmesser givesthe children some Brazilian geodesas gifts. A few weeks later, hereceives a package in the mail fromthe two boys with a letter sayingthey loved their geodes and decidedto send him two favorite pebblesfrom their rock collection in thanks.Shortly thereafter, at the end of a lec-ture at Sotheby’s, Mr. Feldmesserdisplayed an Art Deco bracelet, aColombian emerald—and the twosmall stones he received from theboys. The point illustrated was thatall gemstones, by their very nature,are rocks, pebbles, or stones:Sometimes a personal attachment isa more meaningful determinant of astone’s value than the market mightotherwise suggest.

JOSHUA SHEBYGemological Institute of America

New York

362 GEMOLOGICAL ABSTRACTS GEMS & GEMOLOGY WINTER 2004

COLORED STONES AND ORGANIC MATERIALSAlexandrite effect. A. V. Vasiliev. Gemological Bulletin, No. 8,

2003, pp. 28–38 [in Russian with short English abstract].A specially designed computer-controlled spectrometer wasused to obtain absorption spectra to study color-changephenomena in minerals. The following samples were stud-ied: chrysoberyl, emerald, corundum, several garnets, fluo-rite, apatite, stillwellite, and lovchorrite [rinkite]. Usingvarious light sources (i.e., tungsten, mercury, direct sun-light, scattered daylight, D65 fluorescent lamp, and “equalenergy source E”), characteristics of hue, tone, and satura-tion were evaluated and integrated into an analysis of theinfluence of spectral light distribution on color perception.Particular attention was paid to crystal orientation in theanisotropic minerals.

Rubies from Myanmar, Cambodia, and Tanzania, as wellas blue sapphires from the Ural Mountains (Russia), showedparticularly significant color differences between daylight andthe other sources. Spessartine-grossular garnets from Tanzaniashowed a distinct color change, comparable to alexandritefrom the Urals. Much less color change was seen in samples ofspessartine-grossular from Sri Lanka and pyrope from Yakutia.Fluorite from an emerald mine in the Urals showed a notice-able change. A “reverse” alexandrite effect (i.e., blue ratherthan red in tungsten illumination) was observed in grossularfrom Noril’sk (Siberia). Technical explanations for all of theseobservations are given. In the case of apatite, stillwellite, andlovchorrite, which contain rare-earth elements, color changewas seen only when they were compared in daylight and witha mercury lamp.

BMS

Gemological ABSTRACTS

2004EDITOR

A. A. LevinsonUniversity of Calgary

Calgary, Alberta, Canada

REVIEW BOARDJo Ellen Cole

Vista, California

Michelle Walden FinkGIA Gem Laboratory, Carlsbad

R. A. HowieRoyal Holloway, University of London

Alethea InnsGIA Gem Laboratory, Carlsbad

David M. KondoGIA Gem Laboratory, New York

Taijin LuGIA Research, Carlsbad

Wendi M. MayersonGIA Gem Laboratory, New York

Kyaw Soe MoeGIA Gem Laboratory, New York

Keith A. MychalukCalgary, Alberta, Canada

Joshua ShebyGIA Gem Laboratory, New York

James E. ShigleyGIA Research, Carlsbad

Boris M. Shmakin Russian Academy of Sciences, Irkutsk, Russia

Russell ShorGIA, Carlsbad

Maha TannousGIA Gem Laboratory, Carlsbad

Rolf Tatje Duisburg University, Germany

Christina TaylorBoulder, Colorado

Sharon WakefieldNorthwest Gem Lab, Boise, Idaho

This section is designed to provide as complete a record as prac-tical of the recent literature on gems and gemology. Articles areselected for abstracting solely at the discretion of the section edi-tor and his reviewers, and space limitations may require that weinclude only those articles that we feel will be of greatest interest to our readership.

Requests for reprints of articles abstracted must be addressed tothe author or publisher of the original material.

The reviewer of each article is identified by his or her initials at theend of each abstract. Guest reviewers are identified by their fullnames. Opinions expressed in an abstract belong to the abstrac-ter and in no way reflect the position of Gems & Gemology or GIA.

© 2004 Gemological Institute of America

Features of chemical composition and optical properties ofperidot. A. A. Zolotaryov, A. K. Buiko, A. A. Buiko, andN. O. Ovchinnikov, Gemological Bulletin, No. 10,2003, pp. 14–20 [in Russian with short English abstract].

The properties of 28 faceted gem-quality peridots fromChina, Egypt, Pakistan, Russia, Tanzania, and the U.S. weredetermined. Electron-microprobe analyses showed that allthe samples were predominantly forsterite (Mg2SiO4) with5–15 mol.% fayalite (Fe2SiO4). Peridots from Pakistan andTanzania had lower Fe contents, whereas those from Russiaand the U.S. had higher Fe contents. Variations in Fe affect-ed the colors and R.I. values. Trace elements (e.g., Ni, Mn,and Ca) had a negligible effect on these properties.

The main hues varied between yellowish green andorange-yellow. The yellow component was correlated toFe. A good correlation was found between Fe content andthe highest refractive index (ng), which ranged between1.680 and 1.698. Peridots from Pakistan (lower Fe con-tents) were optically positive, whereas those from Russiaand the U.S. (higher Fe contents) were optically negative.The birefringence was at least 0.017; this is a distinguish-ing characteristic and enables peridot to be separated fromsinhalite (MgAlBO4, birefringence 0.008), which otherwisehas optical properties very similar to peridot. BMS

High-pressure, metasomatic rocks along the Motaguafault zone, Guatemala. G. E. Harlow, V. B. Sisson,H. G. Avé Lallemant, S. S. Sorensen, and R. Seitz,Ofioliti, Vol. 28, No. 2, 2003, pp. 115–120.

The Motagua fault zone in central Guatemala forms thepresent boundary between the North American andCaribbean plates, and is the world’s second most impor-tant source of jadeite (after Myanmar). It consists of twomajor subparallel faults, the San Augustín and theCabañas, where high-pressure/low-temperature rocksoccur. Jadeite is hosted by sheared serpentinite bodies, pri-marily on both the northern and southern sides of theCabañas fault. However, there are distinct mineralogicaldifferences in the jadeite belts on either side of the fault.Late-stage alteration, grain-boundary alteration, and albiti-zation are present in jadeites from the northern side of thefault, whereas these features have not been documented injadeites from the more recently discovered southern bod-ies. Further, jadeites from some areas of the southern beltare more translucent and darker colored (in addition, someare blue) than their northern counterparts.

The authors propose that the Guatemalan jadeitescrystallized from seawater-like fluids derived from a sub-ducting plate that entered into a serpentinizing peridotitebody. The jadeite formed at temperatures of 100–400°Cand pressures of 5–11 kbar. Because jadeites (and associat-ed high-pressure/low-temperature rocks) in the two beltsshow different mineral assemblages with distinctive prop-erties, the Motagua fault zone may record two collisionalevents. Alternatively, these two belts may represent differ-ent structural levels of one subduction complex. KSM

Problem in Chinese fresh-water pearl industry and counter-measure. J. Zhao and R. Yang, Journal of Gems andGemmology, Vol. 5, No. 4, 2003, pp. 42–45 [inChinese with English abstract].

China is both the world’s largest producer and largestexporter of freshwater cultured pearls. However, comparedto the late 1990s, much of the industry is facing problemsof decreasing quality and falling prices, which threaten tohinder further development. Reasons for these problemsinclude the following: (1) There are no controls on produc-tion, (2) technological advances to improve cultivation andthe quality of production have not been implemented, and(3) water quality in some of the most important growingareas is afflicted by pollution (i.e., excessive amounts ofnutrients, toxic materials, and suspended matter).

Possible solutions to these challenges are offered: (1)Scientific management and state regulation of productionshould be implemented; (2) the industry should be reorga-nized with the consolidation of small operations into larg-er, more efficient companies and cooperatives; (3) researchaimed at improving all aspects of the industry should beencouraged and more specialists trained; (4) laws to reducepollution and improve the growth environment for thepearl-producing mollusks should be enacted and enforced;and (5) brand names for Chinese cultured pearls on theinternational markets should be developed to help addvalue. TL

TPR, EPR and UV-Vis studies of Ni(II) speciation inchrysoprase. Z. Sojka, S. Witkowski, W. Zabinski,K. Dyrek, and E. Bidzinska, Neues Jahrbuch fürMineralogie, Monatshefte, No. 1, 2004, pp. 11–25.

TPR (temperature programmed reduction), EPR (electronparamagnetic resonance), and ultraviolet-visible spectro-scopic methods were used to study the local environment(i.e., lattice sites) in which nickel ions (the green chro-mophore) occur in chrysoprase from three localities:Szklary, Lower Silesia, Poland (“apple” green, 1.71 wt.%Ni); Marlborough Creek, Australia (“emerald” green, 0.98wt.% Ni); and an unknown African locality (dark green,4.38 wt.% Ni). The authors demonstrated that nickel ispresent in two different forms: It is predominantly dis-persed into 2:1 phyllosilicates (similar to Ni-talc), and lesscommonly it is found as extra-framework species adsorbedonto the surface of the chalcedony. RAH

DIAMONDSElectron microscopy analysis of debris produced during

diamond polishing. F. M. van Bouwelen, J. E. Field,and L. M. Brown, Philosophical Magazine, Vol. 83,No. 7, 2003, pp. 839–855.

Diamond’s hardness is anisotropic, and therefore it showsdifferent polishing rates according to crystallographicdirection. Historically, diamond polishing was explained

GEMOLOGICAL ABSTRACTS GEMS & GEMOLOGY WINTER 2004 363

364 GEMOLOGICAL ABSTRACTS GEMS & GEMOLOGY WINTER 2004

in terms of microcleavage along octahedral planes, as tinyirregularities on a diamond’s surface contact the scaife.However, various investigations conducted in the 1990s ofthe details of polished diamond surfaces found no evidencefor this hypothesis. Other studies have attempted to exam-ine the debris from polishing, but they were marred by thedifficulties in obtaining pristine samples.

The present authors collected polishing debris on asmall copper screen coated with a SiO film, hung slightlyabove the scaife and about 2 cm behind the diamondbeing polished. The debris ejected from various diamondfaces and from different polishing directions was exam-ined both visually and chemically.

High-resolution electron microscopy showed abun-dant amorphous carbon in the debris taken from all pol-ishing directions. Patches of graphite also were found inthe debris. In the sequence of samples from softer to hard-er direction, the ratio of graphite to amorphous carbondecreased. However, attempts to polish the octahedralplanes themselves produced debris with relatively largesheets of graphite and angular fragments of diamond (butno cleavage fragments).

Electron-energy-loss spectroscopy enabled the authorsto characterize the debris chemically and to calculate abulk density of 1.9 g/cm3 for the debris from the softerdirections, 2.2 g/cm3 for debris from a harder directionalong the cubic plane, and 2.3 g/cm3 (the density ofgraphite) for debris from the octahedral plane. High-ener-gy-loss spectra indicated the presence of a form of amor-phous carbon. The spectra revealed no nitrogen, but oxy-gen was present at 2–4 atom%, with more oxygen in thedebris from softer directions. Assuming only carbon andoxygen in the debris, the authors calculated an sp2-to-sp3

ratio (the ratio of graphite bonds to diamond bonds) thatindicates graphite constitutes 80–100% of the debris forall samples except those from the octahedral plane.

Rather than microcleavage, the authors concludedthat the pressure of polishing transforms the surficiallayer of diamond to graphite, which is then readilyremoved. Studies by other researchers of the anisotropicdistribution of compressive stress during diamond polish-ing along different directions also support this conclusion.Last, the authors use this conclusion to explain why alayer of black powder is created when preparing a newscaife. Ilene Reinitz

FISH—State-of-the-art technology in final diamond recov-ery. L. du Plessis and M. Sewawa, Journal of theSouth African Institute of Mining and Metallurgy,Vol. 103, No. 9, 2003, pp. 557–562.

This process-engineering article reviews diamond recoverytechnology recently employed at Debswana’s Jwanengmine in Botswana. FISH, or Fully Integrated Sort House,has improved three key areas of final diamond recovery:sorting efficiency, availability of production information(turn-around time), and security. FISH, in combination

with CARP (or Completely Automated Recovery Plant),was jointly installed at the Jwaneng recovery plant (called“Aquarium”) in late 2000.

Through the integration of several commerciallyproven technologies, the FISH process streamlines feedpreparation and the sorting, cleaning, and packing of recov-ered diamonds. Sorting efficiency improvements were real-ized by introducing X-ray and laser (Raman spectroscopy)equipment. In turn, decommissioning the maintenance-intensive grease belts improved turn-around times. Thenew equipment allows “hands-off” operation and mainte-nance (i.e., human hands do not touch diamonds or dia-mond concentrate), thus improving product security.

The article also discusses lessons learned from theimplementation of these new technologies, such as per-sonnel issues, data collection, and operational feedback.For example, an increase in the number of technical staffwas required to cope with the new equipment demands,yet overall operational costs dropped due to efficienciesgained in other areas. Interestingly, Debswana concludedthat the successful integration of various technologiesproved to be more innovative than the individual tech-nologies themselves. KAM

On grading the asymmetry of a round brilliant-cut dia-mond. S. B. Sivovolenko, Yu. B. Shelementyev, andG. Holloway, Gemological Bulletin, No. 9, 2003,pp. 18–25 [in Russian with short English abstract].

Symmetry in round brilliant cut diamonds is evaluateddifferently in Russia, Belgium, and the U.S. This articlesummarizes and compares characteristics of the symme-try-evaluation methods used in these countries, with par-ticular emphasis on the cause, effect, and importance ofasymmetry. Asymmetry is explained as the degree ofmutual deviation from the ideal of the table and pavilionaxes. Based on a computer-generated 3D model, a newmethod for grading asymmetry in round brilliant dia-monds is proposed. The article is critical of some aspectsof the HRD and GIA methods, particularly where certaindeviations from the “ideal” are designated as “important”or “unimportant.” The authors maintain that it is morecorrect to separate the deviations into two categories: (1)those that influence optical properties, and (2) those thatsimply reflect the skill of a cutter—that is, they are easilyvisible but not very significant. BMS

Options for selling rough. J. Chapman, Rough DiamondReview, No. 2, 2003, pp. 16–18.

In an industry where rough diamond producers haveunique production profiles and monthly outputs, the suc-cessful sale of rough requires careful consideration. Nolonger is De Beers virtually the sole buying organization,as in decades past. Today, several avenues are available toprimary producers. Sellers of (legitimate) rough may usediamond bourses or exchanges, find contract buyers, enterinto investor-dealer arrangements, use tendering agents or

GEMOLOGICAL ABSTRACTS GEMS & GEMOLOGY WINTER 2004 365

brokers, or establish a sales office. Some caveats for theseoptions are given, such as the care required in assemblingparcels that will appeal to purchasers, as well as the neces-sity of well-defined contractual obligations regarding con-tract sales and investors. The article recommends thatexperts be consulted in many cases, such as for valuationpurposes, product presentation, advice on local demandand governmental regulations, and marketing. Althoughoptimizing sales of rough is complex, current high demandplaces producers in a position of strength, which can beexploited with an appreciation of the advantages andshortcomings of various selling practices. DMK

The preservation of alluvial diamond deposits in aban-doned meanders of the middle-Orange River. P. G.Gresse, Journal of the South African Institute ofMining and Metallurgy, Vol. 103, No. 9, 2003, pp.535–538.

The Orange River has transported diamonds eroded fromkimberlites and intermediate secondary sources in SouthAfrica’s interior and deposited them within gravel terracesalong much of its length. These terraces are typically pre-served at distinct elevations above the current river level,but were not recognized during most of the 20th centuryas they were capped by younger sediments. Within thepast four years, some of these terraces have been success-fully mined, particularly along the “mid-Orange River”section between Douglas and Prieska in South Africa’sNorthern Cape Province.

Each terrace has a characteristic diamond content andage. For example, the most consistent diamondiferous pale-odeposit is located 60–90 m above the current river leveland was formed in the mid-Miocene (~8 million years ago).Each time the river cut more deeply into the valley as aresult of sea-level or other changes, it would partiallyrework the previous cycle’s gravel deposits, including itsdiamonds. The diamond content of any one gravel terraceis dependent on the amount of diamonds introduced fromupstream by the paleoriver, the number of reworked dia-monds from the previous cycle’s gravels, and the amount ofdilution material present. Data on the internal structureand morphology of these deposits are obtained throughdrilling and high-resolution aeromagnetic surveys, the lat-ter being particularly effective in delineating those terracesthat contain a large amount of iron (originally sourced frombanded iron formations in the area). A high iron contentcorrelates with a higher diamond content; apparently, theadded density of the iron-bearing gravels enhanced the trap-ping mechanism for diamonds. KAM

Revival of the Skeleton Coast. R. Baxter-Brown, RoughDiamond Review, No. 3, 2003, pp. 27–30.

The Skeleton Coast, a narrow, 800-km-long stretch ofdesert bordering the Atlantic Ocean in northern Namibia,encompasses rugged terrain lacking in infrastructure; it isan inhospitable environment for diamond exploration.

Rusting pieces of machinery and prospecting pits fromexploration between 1943 and 1971 are reminders of failedventures. Urged to open the Skeleton Coast for explorationonce again, the government of Namibia granted the firstdiamond prospecting licenses for the region in recenttimes in 1999. Exploration activities were delayed until2001 due to environmental concerns. Since then, somesuccessful ventures have been launched in the area, andore-reserve evaluation programs have identified severalpotentially profitable areas.

The origin of the Skeleton Coast diamonds is problem-atic. Various possibilities have been proposed, but the mostfavored is that the diamonds originated in kimberlites inAngola and were brought to the Skeleton Coast by south-flowing Angolan rivers starting in late Tertiary time.

MT

Selection of plant for diamond ore concentration. T.Mason, Rough Diamond Review, No. 2, 2003, pp.33–38.

One of the most important steps in diamond mining isthe concentration of diamonds, along with other heavyminerals, from the kimberlite or alluvial ore prior to rout-ing the concentrate to an X-ray sorter or grease-table sepa-rator. The goal is to minimize the volume of material thatmust be processed during the final recovery stage. Thetechniques of primary concentration are based on density,and their principle of operation is called “densimetric sep-aration.” Dense-medium separators such as HM (heavy-medium) cyclones, jigs, and pans are described, and theirefficacy is discussed. Although cyclones are very efficient,a more economic concentration of diamondiferous orecan be attained by using them in conjunction with sim-pler devices such as jigs, pans, and shakers. The authorrecommends that diamond mining projects use densimet-ric ore profiles to develop effective and efficient plantdesigns. DMK

INSTRUMENTS AND TECHNIQUESAplicações de microscopia eletrônica de varredura (MEV) e

sistema de energia dispersiva (EDS) no estudo degemas: Exemplos Brasileiros [The application ofscanning electron microscopy (SEM) and energy-dis-persive spectroscopy (EDS) to gem research:Brazilian examples]. L. da C. Duarte, P. L. Juchem,G. M. Pulz, T. M. M. Brum, N. Chodur, A. Liccardo,A. C. Fischer, and R. B. Acauan, Pesquisas emGeociências, Vol. 30, No. 2, 2003, pp. 3–15 [inPortuguese with English abstract].

The inclusions in several Brazilian gems were studiedusing SEM and EDS techniques. Emeralds from CamposVerdes, Goiás State, were found to contain inclusions oftalc, dolomite, chromite, pyrite, magnetite, and sylvite(KCl; in fluid inclusions). The emeralds are color zoned,

366 GEMOLOGICAL ABSTRACTS GEMS & GEMOLOGY WINTER 2004

with outer green regions that are richer in Cr3+ than theinner near-colorless zones. Amethysts from Rio Grandedo Sul State contain needle-like inclusions of goethite,rather than cacoxenite and rutile as suggested previously.Agate and quartz geodes from the same state containpyrolusite and hollandite. The “silk” effect in corundumfrom Barra Velhe (Santa Caterina State) is due to inclu-sions of diaspore, while asterism in this corundum isattributed to needle-like channels. Rounded zircons arecommon inclusions in corundum from various localitiesin Minas Gerais State, and some have sillimanite and/orkyanite inclusions that suggest a metamorphic origin.

RAH

The detection of colour-enhanced and synthetic gem dia-monds by optical spectroscopy. A. T. Collins,Diamond and Related Materials, Vol. 12, No.10–11, 2003, pp. 1976–1983.

More than five decades of fundamental research on theoptical properties of defects in diamond provide the basisfor today’s gem-testing laboratories to assess gem-qualitydiamonds. In the majority of cases, spectroscopic analysisenables the determination of the origin of color—naturalor treated—as well as the differentiation of synthetic fromnatural. This paper is a compendium of benchmark opticalproperties that define these separations.

It begins with an overview of the specific defects—nitrogen, boron, and plastic deformation—responsible forthe various natural and treated colors seen in diamond. Itthen reviews the primary optical characteristics resultingfrom radiation damage and subsequent annealing, as wellas HPHT processing. Concluding paragraphs detail thedistinguishing defect properties of both near-colorless andcolored HPHT-grown synthetic diamonds. SW

In situ mobile subaquatic archaeometry evaluated by non-destructive Raman microscopy of gemstones lyingunder impure waters. D. C. Smith, SpectrochimicaActa Part A, Vol. 59, No. 10, 2003, pp. 2353–2369.

Laboratory simulation experiments were conducted todetermine the feasibility of identifying cultural heritageobjects at an underwater archaeological site with a mobileRaman microspectroscopy (MRM) system. Three gemmaterials (zircon, amazonite, and sodalite) were placedunder different kinds of pure and impure waters (the latterrepresenting waters containing dissolved or suspendedorganic or inorganic material that might typically be foundat an underwater site). The optical objective of the Ramanmicroscope was immersed in the water to eliminate thenormal aerial pathway of the laser beam between theobjective and the item being analyzed.

Raman spectral band intensities were found to bestronger than, similar to, or weaker than spectra for thesame gem minerals recorded in air. Nevertheless, diagnos-tic bands could be recognized in the spectra recorded forsamples in the pure and impure waters, although some of

the inherent problems presented by Raman analysis (e.g.,fluorescence) remained. A number of technological, scien-tific, and archaeological considerations for in situ MRManalysis of objects underwater are discussed, and it is con-cluded that subaquatic archaeometry by MRM could be aviable technique at certain sites. On-site experiments toauthenticate this new approach have not yet been con-ducted. JES

Rank correlation of laser-induced breakdown spectroscop-ic data for the identification of alloys used in jewel-ry manufacture. A. Jurado-López and M. D. Luquede Castro, Spectrochimica Acta Part B, Vol. 58, No.7, 2003, pp. 1291–1299.

Laser-induced breakdown spectrometry (LIBS) is a mini-mally destructive, rapid, reliable, and relatively inexpen-sive spectroscopic technique. This article describes theapplication of LIBS to the multi-element analysis of 32alloys that are widely used in jewelry manufacture; 25were chosen as library standards, and the remaining sevenwere used as samples. The alloys were divided into twogroups: one for gold alloys used in jewelry manufacturingand the other for low-melting welding points. Each alloywas subjected to five laser shots to obtain a representativespectrum. The Spearman rank correlation coefficients ofthe spectra were compared to the library standards bymean of ranks from 1 to 1024 (the latter representing themost intense pixel in a given spectrum). The maximumrank was obtained when the composition of the alloy wassimilar to that of the standard.

Cu and Zn were detected in all the alloys, whereas Agwas found in most of them. Ni was found only in whitegold; Ir was common (~12–30 wt.%) in most of the alloysused for welding points. Although Cd is currently not per-mitted in jewelry because of its toxicity, this element wasdetected in one of the welding point alloys.

In addition to its usefulness in the jewelry trade, LIBShas great potential for a wide range of industrial applica-tions, especially in the mining and chemical processingindustries. KSM

Spectra of gem materials. G. Pearson, Australian Gem-mologist, Vol. 21, No. 12, 2003, pp. 478–485.

Discrepancies are commonly observed in the spectra ofgem materials seen with a hand spectroscope and thoseobtained with a UV-Vis spectrophotometer. This raisesquestions about the visibility, in hand-held spectro-scopes, of absorption features that have been long-recog-nized as characteristic of many gems, such as sapphireand peridot. By defining and illustrating the “relativeluminous efficiency” curve, which represents the sensi-tivity of human vision across the visible wavelengthrange, the author concludes that some of the instrumen-tally derived absorption spectra presented in manygemology texts cannot be seen with a hand-held spectro-scope. RAH

GEMOLOGICAL ABSTRACTS GEMS & GEMOLOGY WINTER 2004 367

The using of luminescence in gemology. B. S. Gorobets,O. V. Kononov, A. A. Rogojine, and T. D. Kvitko,Gemological Bulletin, No. 10, 2003, pp. 34–56 [inRussian with short English abstract].

This comprehensive review of the applications of lumines-cence methods in gemology contains five tables, 52 figureswith spectra of minerals (including their synthetic ana-logues and simulants), and 11 color photos. General topicsinclude a discussion of luminescence types (e.g., cathodo-and thermoluminescence) and the nature of luminosity—with special attention paid to the effects of Fe, Cu, andradiation defects. The techniques and instruments used forobtaining luminescence spectra also are described.Recommendations are given for the visual observation ofthermal and UV luminescence in diamonds and emeralds,and methods are provided by which their synthetic coun-terparts can be distinguished.

Future work by the authors will be directed toward cre-ating an extensive database for natural and treated gems,compiling specific instructions for using luminescence todistinguish natural from synthetic gems, and establishinga research center in Russia dedicated to developing meth-ods and instrumentation for luminescent determinationsof gems and related materials. BMS

JEWELRY RETAILINGThe role of branding in the diamond industry. A. Murray,

Rough Diamond Review, No. 3, 2003, pp. 34,37–38.

With its “Diamonds are Forever” campaign, De Beers hasprovided sustained global guidance since the 1940s.Although diamonds had been highly revered for genera-tions, they did not become a mass consumer product untilDe Beers promoted them. As new producers and corporateplayers have entered the diamond market in recent years,the consumer’s choice has increasingly been influenced bybranding. The initial brands, usually based on particularcuts of polished diamonds (e.g., the Quadrillion and Idealcut), have increased consumer confidence and given dia-monds an added prestige that makes them popular andsought after. Another brand dimension is provided bycountry of origin (e.g., Australia or Canada) or specificmines in those countries (e.g., Argyle or Ekati, respective-ly). These can summon strong, sometimes patriotic feel-ings from customers. Positioning also plays an importantrole in diamond branding, as having a corporate identitycan help a company in various commercial ways as well asdistinguish it from other players.

Branding and positioning require commitment, as theirbenefits pay off over the long run; results take at least ayear or two to become evident. The long-term view is con-sistent with the soul of the diamond industry, which hasalways been about building and maintaining relationships,as well as establishing values. MT

SYNTHETICS AND SIMULANTSEffect of HPHT annealing on the photoluminescence of

synthetic diamonds grown in the Fe–Ni–C system.A. Yelisseyev, S. Lawson, I. Sildos, A. Osvet, V.Nadolinny, B. Feigelson, J. M. Baker, M. Newton,and O. Yuryeva, Diamond and Related Materials,Vol. 12, No. 12, 2003, pp. 2147–2168.

Absorption and photoluminescence (PL) spectra wereemployed to characterize the effects of HPHT annealingon synthetic diamond crystals containing high concentra-tions of nitrogen and nickel impurities. Twenty syntheticdiamond crystals were grown from an Fe-Ni-C system at1,600 K and 5.5 GPa in a split-sphere type apparatus. Someof the crystals were subsequently annealed for 4 hours ateither 1,950 K or 2,200 K. Additional samples used forcomparison included crystals grown in a Ni-free (Fe-C) sys-tem as well as several Yakutian diamonds with relativelyhigh Ni concentrations for natural stones.

Numerous narrow lines were observed in the PL spec-tra of the synthetic diamonds containing nickel and nitro-gen impurities. More than 20 vibronic systems were iden-tified, some for the first time, and their responses beforeand after annealing were recorded. Based on analysis ofthese data, the authors proffer the following main groupsfor characterizing these systems:

I. Systems existing in as-grown synthetic diamonds thatdecrease in intensity with annealing at 1,950 K

II. Systems that appear after annealing at 1,950 K andthen decrease in intensity or disappear with annealingat 2,200 K

III. Systems that appear after annealing at 1,950 K and donot decrease in intensity with annealing at 2,200 K

Group I systems are identified by individual impurity ionssuch as negatively charged substitutional nickel. Group IIsystems relate to a nickel ion in a di-vacancy position andintermediate nickel-nitrogen complexes containing singlenitrogen atoms. Group III systems correlate with morecomplicated nickel-nitrogen complexes comprising atleast two nitrogen atoms surrounding the nickel.

SW

Optical properties of synthetic diamond single crystals.A. V. Mudryi, T. P. Larionova, I. A. Shakin, G. A.Gusakov, G. A. Dubrov, and V. V. Tikhonov, Semi-conductors, Vol. 38, No. 5, 2004, pp. 520–523.

Synthetic diamond crystals (4–7 mm in diameter) withpotential for use in precision scientific instruments weregrown by the thermal gradient method (Ni-Fe-C system;1,750–1,800 K; 5.4–5.5 GPa) and subsequently subjected toHPHT treatment (2,000–2,200 K and 6.0–6.5 GPa for 3–24hours). The untreated crystals were yellow-green andexhibited a prominent S3 band at 496.7 nm in their cryo-genic PL spectra. The HPHT-treated synthetic diamondshad a pale green color and displayed the S3 band in addition

368 GEMOLOGICAL ABSTRACTS GEMS & GEMOLOGY WINTER 2004

to three S2 bands at 523.3, 489.1, and 477.8 nm (i.e., A, B,and C defects, respectively, of S2). Although the S2 bandswere found occasionally in untreated samples, their inten-sities increased by factors of 5–10, and the overall lumines-cence of the synthetic diamonds increased by factors of3–5, after HPHT treatment. The increase in luminescenceis attributed to a redistribution of Ni and N impuritieswithin the synthetic diamonds during treatment and a cor-responding change in bodycolor. Luminescence excitationspectra further indicated that S2 (A) and S2 (B) are indepen-dent features related to different defects. IR absorptionspectra of the same samples show that HPHT treatmentresulted in aggregation of >90% of the C defects (single sub-stitutional N) into A defects and the near-complete anneal-ing of Me-X centers (Me = metal solvent; X may be carbonand/or nitrogen). PL and IR data confirmed that HPHTtreatment resulted in significant reconfiguration of thedefects in the synthetic diamond lattice.

Christopher M. Breeding

Properties and diagnostics of natural and synthetic mala-chite. T. V. Chernenko and E. P. Melnikov, Gemo-logical Bulletin, No. 8 (pp. 11–27) and No. 9 (pp.31–35), 2003 [in Russian with short Englishabstracts].

This in-depth, well-illustrated two-part article on mala-chite reviews the history of its use in jewelry and as a dec-orative stone, the geology of its major deposits, and meth-ods by which it is synthesized. Based on a study of 150natural and ~20 synthetic malachites, the authors identi-fied textural, structural, chemical, and other differencesbetween the natural and synthetic samples. For example,their densities are distinctive (3.87–3.92 g/cm3 for naturaland 3.61–3.70 g/cm3 for synthetic). Chemically, naturalmalachites contain P (due to admixed pseudomalachite),Be, Co, and V that distinguish them from synthetic mala-chites, which contain Pb, Sn, and Ga (not found in naturalsamples). Numerous other trace elements may be presentin both natural and synthetic malachites, and in somecases these can be correlated to differences in color andtexture. Individual crystallites in natural malachites arelarger than similar crystallites in the synthetic varieties.

Chemical and temperature parameters are determinedfor the formation of the two most attractive varieties ofnatural malachite, with the Russian names “plissovy”(radiating fibers) and “biryuzovy” (light green “turquoise-like”). “Plissovy” forms in gossans over Cu-Fe depositsfrom solutions with low concentrations of Cu and CO2 attemperatures of 60–70°C. “Biryuzovy” usually forms inCu-bearing clays associated with limestones in karst ter-ranes from concentrated solutions at temperatures of20–50°C. BMS

Study on large-sized ruby grown by temperature gradienttechnique. C. Song, S. Zhou, J. Si, H. Li, G. Zhou, Y.Hang, and J. Xu, Journal of Synthetic Crystals, Vol.32, No. 5, 2003, pp. 423–426 [in Chinese withEnglish abstract].

Large crystals of synthetic ruby (not of gem quality) weregrown by the temperature gradient technique from seedplates using Al2O3 powders mixed with 0.5–3% Cr2O3.Crystallization started at 2,050°C; cooling rates were0.5–2.5°C/hour. The largest crystal measured 75 mm indiameter, 45 mm long, and weighed 1,076 g. This crystalwas dark red in the center and even darker red (almostblack) at its edges and bottom. Wave-like growth bandswere observed in the top portion, while clouds of minuteinclusions were concentrated near the seed plate. The con-centration of the inclusions decreased from edge to centerand from bottom to top, resulting in a “trumpet”-shapeddistribution along the growth direction similar to thatfound in synthetic Ti-doped sapphire crystals grown by thesame technique.

Electron-microprobe analysis showed that the inclu-sions were mainly uncrystallized Al2O3 powder. Gas bub-bles or voids also were observed. Microprobe and spectro-scopic (visible range) data showed that the Cr3+ concentra-tion increased in two directions (i.e., from center to edgeand from bottom to top), corresponding to the growth pro-gression. The authors propose that the quality of syntheticruby crystals produced by this method could be improvedby optimizing the cooling rate, purifying the raw materials,and controlling the temperature during growth. TL

A Verneuil synthetic ruby showing diverse veil-like‘fingerprints.’ J. M. Duroc-Danner, Journal of Gem-mology, Vol. 28, No. 8, 2003, pp. 483–488.

Today the treatment of gem corundum is of such concernthat it tends to overshadow the topic of natural vs. syn-thetic. This article brings that topic back into the fore-front, as its focus is on a 2.06 ct, oval-shaped, flame-fusionsynthetic ruby that was discovered in a parcel of naturalrubies being checked for country of origin.

This synthetic ruby was treated (i.e., quench-crackledwith flux “fingerprints” later induced) to more closelyresemble a natural ruby. The fingerprints were similar tothose seen frequently in Mong Hsu rubies and could easilyfool anyone viewing the stone with a 10¥ loupe. Only care-ful observation at higher magnification revealed the tell-tale signs of the stone’s synthetic origin: curved striae andclouds of tiny gas bubbles, both hidden beneath numerouswispy, veil-like, flux-induced fingerprints that varied intheir appearance throughout the stone. Also helping tomask the evidence of synthesis were many surface-reach-ing fractures and straight, heavy polish lines. WMM

376 THE LAST PAGE GEMS & GEMOLOGY WINTER 2004

ven if you’ve never heard of a “lenticular” image,chances are you’ve seen one. The term refers to a type oftwo-dimensional printed image, typically seen in novelty

and promotional items, that creates the illusion of motionwhen tilted or viewed from different perspectives. The oddname comes from the grooved plastic lenses, or lenticules,that you feel when you run a fingernail across the surface.

Lenticular images are often confused with holograms,which also show apparent depth and motion, but the twoare actually quite different. Unlike holograms, which areproduced by the reflec-tion of laser light ontoa very thin metallic ortransparent sheet,lenticular printing isdone using a tradition-al lithographic printingpress. And while holo-grams are usuallymonochromatic (butwith a rainbow-likecast), lenticulars aremuch clearer andbrighter, with full pho-tographic color.

Lenticular imaging isby no means a newtechnology. The princi-ple was first developednearly a century agoby Gabriel Lippman(1845–1921), theFrench physicist betterknown for developing the first color photograph plate. AfterWorld War II, when improvements in plastics technologymade them commercially viable, lenticulars became popu-lar in advertising displays and collectibles such as baseballcards and political campaign buttons. Most of these weresimple “flips” between two images. Today’s far moresophisticated products can show a variety of visual effects,including video-like animation, three-dimensional depth,and seamless morphing from one image to another.

FOR THE FALL 2004 G&G COVER, we used a lenticular imageto replicate a basic yet meaningful routine familiar to everyjeweler and gemologist: tilting a diamond to observe it from

different angles. The Fall cover’s five-frame sequencedemonstrates how a diamond’s appearance changes basedon the viewing direction, a key concept from the lead article,“A Foundation for Grading the Overall Cut Quality of RoundBrilliant Cut Diamonds” (pp. 202–228).

So how was this unique G&G cover created? First, photogra-phers Harold and Erica Van Pelt shot a 4.01 ct round brilliantcut diamond from a variety of different angles. From these, fivesource photos (illustrated on pp. 197–198 of the Fall issue)were chosen and color corrected, and the color separations

were sent to the printer,Standard Register, forlenticular processing.The photos were digital-ly divided into narrow,linear strips and inter-laced—imagine a deckof cards being shuffled—to produce a sequentialcombination of the fiveframes. This interlacedimage was printed andthen mounted behind aplastic lens screen con-taining horizontal rowsof lenticules. Each lenswas matched preciselywith the narrow strip ofimage behind it, focus-ing on and magnifying it.In the finished lenticular,the eye sees only one setof strips (i.e., one image)at a time depending on

the viewing angle. Any shift in the horizontal viewing angle,either by tilting the cover or changing the viewing position,brings a different set of strips into focus and changes theappearance of the overall image.

We’d like to think of our Fall 2004 lenticular cover as notjust an eye-catching visual, but as a medium that activelyengaged and involved everyone who picked up a copy. Wehope it reinforced the landmark article on diamond cut—and maybe pushed our boundaries a little in the process.

Stuart OverlinAssociate Editor

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Diamond Animation on Our Fall CoverLAST Page

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