THE AMERICAN MINERAI,OGIST, VOL. 53, JANUARY_FEBRUARY, 1968

CHEMICAL DIFFERENCES AMONG THE SERPENTINE,.POLYMORPHS''1

Nonuex J Pacn, LI .5. Geologicol Suruey, Menlo Park,California

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Existing wet chemical analyses and structural studies of the serpentine minerals, chryso-tile, Iizardite, and antigorite suggest that these minerals have different chemical composi-tions and could be identified by composition alone. Triangular composition diagrams, astatistical treatment of the oxide components, MgO, FeO, FezOa, AIzOa, and HsO, and cal-culated mineral formulae from chemical analyses all suggest that chrysotile, iizardite, andantigorite are not polymorphs. Antigorite is distinguished by its comparatively low H:Oand high SiO2 contents. Chrysotile is characterized by a relatively high HrO and MgO con-tent and by a small ratio of FezOa to FeO; while lizardite has hieh SiOz and low FeO con-tents.

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Chrysotile, lizardite, and antigorite compose the serpentine-groupminerals. Much discussion has been centered around the nature of therelations among these mineral species and the ultimate question: Are theserpentines polymorphs or are they separate but similar mineral specieswhich can be distinguished by chemical analyses? Though the answer tothis question is controversial at present, it is important for the interpre-tation of alteration phenomena of ultramafic rocks. Although past chem-ical and crystallographic studies indicate that the serpentine-groupminerals have essentially the same structural foundation and similarformulae, the many existing chemical analyses and structural studieshave not been consolidated into a cohesive interpretation. These resultsare synthesized in this paper to show that the serpentine-group minerals,based on the available analyses, are either members of a complex solid-solution series or are separate chemical species, but are not simply poly-morphs. A polymorph is a substance that crystallizes in more than oneform or crystal structure, all forms or structures having identical chemi-cal compositions.

Unfortunately, in the past, a large number of names have been appliedto individual samples of serpentine-group minerals, generally based ontextures and appearance of the specimens. Faust and Fahey (1962) pro-vide a comprehensive discussion of this aspect so that it need not be con-sidered here. The best classification of the minerals in the serpentinegroup is that of Whittaker and Zussman (1956) based on the X-raydiffraction results. This classification is used here as given below:

I Publication authorized by the Director, U. S. Geological Survey.

201

202 NORMAN J PAGE

The present study was begun at the University of California wheremost of the work was done; research has been continued at the U.S.Geological Survey.

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Although other structures for serpentines have been proposed, theevidence presented by Warren and Hering (194I), Aruja (1945), and

Whittaker (1953) demonstrates that all serpentine minerals, includingthe fibrous varieties, have a trioctahedral structure analogous to diocta-hedral kaolinite. As discussed by Bates (1959) and Deer, Howie, andZussman (1962), a major factor repsonsible for the different serpentineminerals is the amount of mis-matching involved in joining a brucite-Iike layer to a tridymite-like layer to form an unit cell of serpentine. AtIeast four possibilities for deriving such structures have been postulated:(1) curving the composite sheets with the tridymite layer forming theconcave part of the cylinder, (2) distorting one or both layers, (3) sub-stituting various ions in either layer to adjust the sizes of the layers,and (4) creating cation vacancies in the octahedral layer and maintainingcharge balance by removing an equivalent amount of hydroxyl ions. Thestructure of chrysoti le is controlled by (1) and (3) with (1) the dominantmean of matching the sheets (Whittaker, 1956a). Method (4) combinedwith (1) and (3) is responsible for the structure of antigorite (Kunze,

1961). Another factor in the development of the different structures ofserpentine minerals is the possibility of both regular and irregular stack-ing of the layers.

Chrysotile. Fankuchen and Schneider (1944) suggested, on the basis ofsmall angle X-ray scattering, that chrysotile consists of fibers on theorder of 200 A in diameter packed in trigonal array along the fibers.Since Turkevich and Hiller (1949) first used an electron microscope todemonstrate that chrysotile apparently had a "hollow tube" morphology,abundant evidence based on the electron microscope observations hasaccumulated (Bates, Sand, and Mink, 1950; NolI and Kircher, 1950,1951; and Maser, Rice, and Klug, 1960). These observations are sup-ported by the detailed structural studies of Whittaker (1957). In a re-cent paper Huggins and Shell (1965) reported bulk densities of chrysoti leranging ftom 2.2 to 2.4 g/cc. Using cylinder diameters of 340 A and 80 Aas outer and inner diameters, respectively, the theoretical bulk density,

SERPI]NTIND "POLYMORPHS" 203

including pore space is 2.19 to 2.25 g/cc. This demonstrates that chryso-ti le has hollow or partially f i l led hollow tubes.

Three varieties of chrvsotile are recognized from single-.frber studies:clinochrysoti le, orthochrysoti le, and parachrysoti le (Whittaker, 1953,1955, 1956a,b,c, and 1957). Ortho- and parachrysoti le are orthorhombicwhile clinochrysoti le is monoclinic (neglecting the curvature). In clino-and orthochrysoti le, the fibers are curved about the o-axes, and anyregular stacking or translational-ordered arrangements would be in ala or -a direction. By the nature of the fiber, translational order cannotoccur in the 6 direction, so that the atoms at the base of layers wouldhave to be restricted to circumferential grooves. Clinochrysotile (Whit-taker, 1956a) has a two-layered cell in which the successive sheets areoffset in the same direction (either -la or -o), with alternate layersoffset by different amounts. Orthochrysoti le (Whittaker, 1956b) has atwo-layered cell and has an orthorhombic cylindrical lattice. AlternateIayers are offset in the la and -a direction. The third variety, para-chrysotile, is defined with 6 as the axis of curvature and has an ortho-rhombic cylindrical lattice. Whittaker (1956c) shows there can be noanalogous partner to parachrysoti le as there is for clino- and orthochryso-ti le.

From Whittaker's study (1956a,b,c) and Whittaker and Zussman(1956), it appears that clinochrysoti le is the most abundant, ortho-chrysoti le is next most abundant, and parachrysoti le is fairly rare ormixed with the other two in small amounts.

Lizardite. Observations under the electron microscope show that lizarditehas a platy morphology (Deer, Howie, and Zussman, t962). Earlypowder work by Whittaker and Zussman (1956) on samples describedbut not named by Midgely (1951), suggested that,l izardite has a single-Iayered unit cell and is pseudo-orthohexagonal, individual layers havingtrigonal symmetry. This was confirmed by the single-crystal analysis ofRucklidge and Zussman (1965). They found thatlizadite is disorderedin three ways: (1) the crystals are macroscopically bent about more thanone crystallographic axis; (2) some layers are rotated by 1800; and (3)some layers are displaced by *(b/3). There are two possible orienta-tions of alizardite layer which can be combined in three ways to producestacking arrangements in an individual crystal.

Antigorite. The structure of antigorite, the other distinct serpentine min-eral, has been elucidated by Aruja (1945), Zussman (1954, 1956), Kunze(1956, 1957, 1958, 1961), Zussman, Brindley and Comer (1957) andChapman and Zussman (1959). Under the electron microscope antigorite

204 NORMAN J PAGT,

exhibits both a platy and fibrous morphology, but there are no sugges-tions of cylindrical tubes. Although antigorite is a single-layered serpen-tine whose c and b dimensions are very simiiar to lizardite, it's o param-eter is large and in many cases approximates 40 A. On the basis of thesingle-crystal studies of Kunze (1956, 1958, 1961) and Zussman (1956),the structure involves deficiencies of hydroxyl and magnesium ions.These deficiencies are repeated along the d axes. The resulting structureis then composed of "half-waves joined by means of Mg-bridges"(Kunze, 1956).

The most frequently occurring a parameters for antigorites studiedby electron diffraction (Zussman, Brindley, Comer, 1957; Chapman andZussman, 1959) are 33.7, 35.8, 4t.2, and 43.0 A. Zussman and co-workersfound that different grains of one sample yielded values oI a of 41, 90,and 110 A, while other fibrous antigorites had o parameters in the rangeof 16 to 10 A (Chapman and Zussman, 1959). Kunze (1961) has treatedthe variation of o parameters from a structural and theoretical approachand considers that antigorites have compositions between talc andchrysoti le which accounts for the octahedral cation and (OH)- deficien-cies. From his structural approach, the various observed values of the aparameter can then be derived theoretically.

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Althouth the formula normally quoted in mineralogical textbooks forserpentine is MgaSizOr(OH)a, or two times this formula, natural serpen-tines are rarely, if ever, composed only of magnesia, sil ica, and water. Inthe general formula X6Y4O10(OH)s, X represents the possibil i ty for thesubstitution of the ions Mg2+, Fe2+, p.a+, Co'+, lr l lz+, n{n2+, Mn3+, Cr3+,Cu2+, Al3+, and Tia+ in octahedral coordinationl Z represents Sia+, AI3+,Bt+ (?) , and Fe3+ in tet rahedral coordinat ion; and OH represents (OH)- ,

Cl - ,F-(?) , and Br-(?) .

Criteria and selection of analyses. In addition to the ions mentioned above,serpentine analyses frequently show some K1+, Nar+, and Ca2+, that areprobably not in the structure but are due to a mineral impurity in theanalyzed concentrate. Even the exact amounts of Fe2+, ps3+, Q13+, fia+,and AI3+ in the structure may not always be known because of the fine-grain size of the serpentine and its intimate association with fine-grained spinels or hydrated oxides, such as goethite or lepidocrocite,which makes physical separation of the minerals almost impossible. It isalso suspected that in some cases the amount of magnesia reported is in-correct and is really due to the mineral impurity brucite. In consideringthe analytical results, both structural state and purity require careful

SERPENTINE I'POLYMORPHS" 205

attention and definition. Analyses of serpentines for which there is notsufficient X.:.ay, optical and textural, DTA and infrared evidence to de-termine the mineral species are not considered here.

The group of analyses considered here was selected from 248 analysesof serpentine mineral done between 1834 and 1962 as compiled by Faustand Fahey (1962). Their discussion (p. 7,79) ol the sources of the analy-ses indicates that the l iterature was well covered and that a wide as-sortment of types was selected by them. For the present study, analyses(Appendix) made on material apparently free of mineralogical impuritiesand identif ied as to mineral type, were chosen. Five new analyses (Page,1967) were added to this group. Comments concerning each analysisused are given in the Appendix; these comments indicate why everyanalysis was not used in each of the following figures. All of the analyseswere recalculated by computerl to mineral formulae, using the hydro-gen-equivalent method. Alkalis and HzO(-) were rejected for the pur-poses of the calculations.

Composit'ional variations of serpent,ine. In Figure 1, the variation in thecomposition of serpentine is represented as weight percent of a specificoxide versus the normalized number of analyses. The five major com-ponents, MgO, SiOz, FeO, FerOa; and AlzOg, are the only oxides con-sidered. Water is discussed later. The number of analyses out of the 86for which the amount of the oxides is available, is indicated in the figure.

The frequency diagrams show that serpentines have a fairly limitedrange of composition. An inspection of the percentage of sample versusweight percent of oxides indicates little chemical difference among thevarious species. The analyses were recalculated to total weight percen-tages of the sets of components MgO, SiOz, HzO; MgO, FeO, SiO2; andMgO, FeO, H2O. The amount of total iron was calculated as FeO andonly HrO(f ) was used for the HzO component except where only totalwater was determined. Figure 2 shows the recalculated analyses forchrysotiles, lizardites, and antigorites.

On the MgO, SiO2, HzO diagram (Fig, 2a),l izardite and chrysoti lecompositions do not differ significantly. Antigorites tend to be higher inSiOz and lower in HzO and MgO than lizardite and chrysotile but someoverlap of the ranges exists which could be caused by errors in separation,identification, or analysis. Lizardites and antigorites tend to have highertotal iron contents than chrysoti les as is demonstrated in the diagramfor MgO, FeO, SiO2 (Fig. 2b). Again, antigorites are grouped separatelyfrom lizardites. In the compositional diagram for MgO, FeO, H2O (Fig.

I Jackson (in press) designed the computer program.

206

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S ERP EN TI N E " POLY MORP H S" 207

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2c),lizardite and antigorite analyses plot differently than the chrysotileanalyses since they have higher total iron content than chrysotiles. Thelizardite and antigorite analyses tend to divide in two groups in whichantigorite is distinguished by having a lower water content.

Other methods of plotting mineral analyses make use of calculatedmineral formulae. In this study, the hydrogen equivalent method wasused to calculate formulae. It is based on the hydrogen-equivalents,that is, on the sum of the anions, O2-, (OH)-, and F- equals 18. Thismethod for finding the number of ions per formula involves calculatingratios of hydrogen equivalents of oxide weight percents and normalizingthese values to twice the sum of anions per unit formula. It is preferredbecause it uses the HzO(*) of an analysis. Mineral formulae for the ser-pentine minerals can also be calculated on the basis of 28 negativecharges and assuming that the OH content of the cell is 8 as was done byFaust and Fahey (1962). Originally Page (1966) used this method andcame to the same general conclusions regarding chemical compositionsand polymorphism, although the number of cations per formulae weredifferent. Since this method neglects the water reported in the analysis,the decision was made not to waste this information in this report.

Figure 3 demonstrates that antigorite and lizardite contain less waterthan chrysotile and that lizardite and antigorite differ chemically fromchrysoti le by havinglower ratios of (Fe2+f Mg'+) to (Fe3+f Als+).

Statistical analys'is of serpent'ine m'ineral' compositions. Given a superioranalysis of a serpentine mineral the structural type of the mineral canusually be ascertained. Analyses marked with an asterisk in the Appendixwere selected for a statistical treatment. The 52 analyses were assignedto one of three groups, lizardite, antigorite, or chrysotile, by X-ray, DTA,or other information, but not on the basis of the chemical analysis. Theweight percent oxides for MgO, FeO, Fe2Os, AlzOa, SiOz and HrO(*)were treated as variables. These data were analyzed with a computer bya l inear discriminant analysis (Program BMD05M, Discriminant Analy-sis for Several Groups, available from the Stanford Computation Cen-ter). The program treats the data (Anderson, 1958) by first comparingthe way in which each variable (oxide weight percent) varies within agroup and the way in which each variable varies with respect to the en-tire set of observations (52 analyses of serpentine minerals). The dif-ferences in the way in which the group and set vary are used to deter-mine linear equations for the groups. Once these equations are deter-mined they are evaluated for each analysis or observation. Using thesefunctional values for each analysis, a probability is calculated and is usedto indicate the likelihood that each observation belongs to any given

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group. Also statistics are calculated whi-ch allow one te test whetherarithmetic means of the three groups are the same.

The evaluation of the statistical analysis for each individual is that outof 31 chrysotiles (originally grouped together) only two were included

SERPENTINE ''POLYMORPHS'' 211

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in other groups than chrysotile, for six lizardites only one was put in

another group and for 15 antigorites only one was put in another group.

If the set of analyses used is representative, then the structural type of

serpentine mineral can be found from the mineral analysis. In Table 1

the means of the analyses for each of the three groups is presented. The

statistical analysis indicate that the means are not the same at greater

than 99.95 percent confidence level.

2I2 NORMAN T PAGE

Besides this type of treatment, all of the analyses were presentedrandomly to the same statistical program and three groups defined by arandom process. These three groups were nearly identical to the groupschosen on a non-chemical basis. Therefore, very l itt le bias was probablyintroduced by the method of selection of the groups.

Rrsur,ts AND CoNCLUSToNS

The chemical differences between the different serpentine minerals asrepresented by the present available analyses are shown in Table 1 byaverage analyses and averageformulae of chrysoti le,I izardite, and antig-orite. The features observed here which differentiate the mineral speciesare the same discussed in the previous section. On the average they are:(1) high SiOz weight percent for l izardite and antigorite, (2) low AlzOecontents for l izardite and chrysoti le, (3) a large ratio of FezOs to FeO forlizardite, (4) low MgO weight percent for antigorite, (5) low HzO weightpercent for antigorite, (6) large numbers of trivalent ions in the tetra-hedral coordination for antigorites, and (7) low Fe2+ in l izardites.

Structural studies of the serpentine minerals, chrysoti le, l izardite, andantigorite indicate that the antigorite structure involves deficiencies ofhydroxyl and magnesium ions whereas the other two mineral structuresdo not involve these. If mineral formulae are calculated on the assump-tion of 28 negative charges (Faust and Fahey, 1962), the average sumof octahedral cations for the selected chrysoti les is 5.97;Lizardite, S.92;and antigorite, 5.65. This is the reverse of Table 1, but the (OH)- forantigorite in Table 1 is quite low, 7.680 as compared with the other twospecies. The actual distribution of cations and anions is probably some-where in between these two results. Since the structure changes the com-position of antigorite from the theoretical end member MgrSizOr(OH)a,antigorite, as is now known, is not a polymorph of chrysotile or lizardite.

Recent microprobe studies by Page (1967) suggest that l izardite andchrysotile are separate mineral species and that lizardite is consistentlymore iron-rich than the associated chrysoti le. Present analytical informa-tion on serpentines and statistical treatments of the same data suggestthat lizardite and chrysotile are not polvmorphs. These arguments applyonly to the presently available analytical information and as yet no onehas managed to obtain an unquestioned serpentine polymorphic transi-tion experimentally (Page, 1966).

This author believes that all serpentine minerals are composed of threesets of solid solutions, one representing lizardite, another chrysotile,and another antigorite, with the possibility of polymorphism or poly-typism within each solid solution series.

S ERP DNT I N E " POLY MORP H S''

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Special thanks are due to Professors W. S. Iyfe, A. Pabst, and H. Hawkes, of the Uni-versity of California, Berkeley. The University also provided part of the financial support,which is gratefuily acknowledged. R. G. Coleman, R. W. Bowen, C. L. Christ, and P B.Hostetler, of the U. S. Geological Survey gave generously of their time and offered manyhelpful suggestions during the research and preparation of the manuscript.

RnlBnnNcns

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Blrns, T. F. (1959) Morphology and crystal chemistry of 1:1 layer lattice silicates. ,4raer.M'inerol'.44,78-114.

---, SaNr, L. B. exo J. F. MrNx (1950) Tubular crystals of chrysotile asbestos. Sciencerrr, 512-513.

Cnaeu.tx, J. A ,lNo J. ZussnaN (1959) Further electron optical observations on crystals ofantigorite. Acta Crystallogr. 12, 550 552.

Dnrn, W. A., R A. Howrn, AND J. ZussMAN (1962) Roek-lormi.ng mineral; V 2 ChainSi,l,icates: V. 3 Skeet Silicates. John Wiley and Sons, Inc , New York.

l'awxucnrx, I. eNn M. ScnNnmen (1944) Low angle X-ray scattering from chrysotiles.J . Amer . Chem. Soc.66, 500.

Fausr, G. T. eNn J. J. Farrnl (1962) The serpentine group minerals. U. S. G eotr Sura. Prof .Pap.38SA,92p.

Huccrxs, C W. eNo H. R. Snnrr. (1965) Density of bulk crysotile and massive serpentine.Am,er. Mineral 50, 1058-1067.

J,r.cr<son, E. D , Bowrw, R. W exn R. E. SrnvaNs (1967) A computer-based procedurefor reduction for mineral analyses to mineral formulas. U. S. GeoI Sunt. Prof . Pap.575-C, C23 C31.

KuNzn, G (1956) Die gewellte Struktur des Antigorits, T. Z. Krirtal,Iogr. 108, 82-107.-- (1957) Die gewellte Struktur des Antigorits. Fortsch. Mi,nual 35,4G48- (1958) Die gewellte Strukture des Antigorits, lL Z. Krislallogr. 71O,282.-- (1961) Antigorit, Sturkturtheoretische Grundlagen und ihre praktische Bedeutung

fur die weitere Serpentin-Iorschung Forstchr. Mineral. 39, no. 2,2OG324.

Lurnnorcn, Haxs (1913) Serpentin in C. Doelter Handbuch d.er Mina'alchemle. Dresdenund Leipzig, 2, no. 1,385-424.

Masrn, M., Rrcn, R. V. .q.Nn H. P. Kr-uc (1960) Chryostile morphology Amu Minerol.45,680 688.

Mrocr-nv, H. G. (1951) A serpentine mineral from Kennack Cove, Lizard, CornwallMineroL. M og. 29, 52G530.

Nor.r, W. AND H. KrRcHEn (1950) Zur Morphologie des Chrystoilasbestos. Naturwissen-schaften 37, 51t0-541

- - (1951) Uber die Morphologie von Asbesten und ihren Zusammen hang mit clerKristallstruktu r. N an es. J ahrb. M in er aI., M on at s h, 10, 219-24n.

Pacn, N. J (1966) Minerdogy ond. chanistry of tke serpenti.ne group mi.nerals ond tlte ser-pmti.ni.zation process.Ph.D. Thesis, University of California, Berkeley, California.

-- (1967) Serpentinization at Burro Mountain, California. Contrib. Mineyal. Petrology

14.321-342.

2t3

214 NORMAN J PAGL,

- AND R. G. ColnueN (1967) Serpentinc mineral anall'ss5 and physical properties.U. S. Geol'. Suru. ProJ. I'ap. 575-8, B103 8107.

Rucrlrncr, J. C , exo J. ZussuaN (1965) The crystal structure of the serpentine mineral,

iizardite MesSirOz(OH)r. Acta Crystallogr. 19, 381 389.Tunrnrtcu, J. axn J. Hrr.r.nn (1949) Electron microscopy of colloidal syslems Anal'.

Chen. 21,475 485.Wamnw, B. E. eNo K. W. Hrnrnc (1941) The ranclom structure ol chrysotile asbestos.

[abstr.] PZ}s. Ret:. 59, 925Wrrtrtarnn, E. J. W. (1953) The structure of chrysotile. A cta Crystallogr. 6, 7 47 .--- (1955) Aclassificationof cylindricallaltices ActaCrystallogr.a,STl 574.--- (1956a) The structure of chrysotile. IL Clinochrysotile. Acta Crystdlogr. 9, 855 861.

- (1956b) The structure of chrysotile. III. Orthochrysotile. Acta Crystdlogr.9,862-864.

-- 11956c) The structure of chrysotile. IV. Parachrysolile. Acta Crystallogr.9, 865-866

-- (1957) The structure of chrysotile. V. Difiuse reflections and fibre Iextrre. Acta

Crystailogr. 10, 149

J. Zussuex (1956) The characterization of serpentine minerals by X-ray dif-

fraction. M,inualog. M ag. 31, 107-126.ZussuaN, J. (1954) Investigation of the crystal structure of anttgorite. Minerdog. Mag 3O,

498-5t2.--- (1956) Antigorite: superlattice and structural formula. Amer. Mi,neroL. 41r 148-152.--, BnrNu.nrr, G W. em J. J. Counn (1957) Electron diffraction studies of serpentine

minerals. Amer. M inual. 42, 133-153.

Monuscr'i,pt receired, May 11, 1967 ; occepteil Jor publi,cotion, September 10, 1967.

AppeNorx: Drscussror. r oF SAMpLES UsBo rN THE SruDy

The sample numbers l isted below are from those analyses of Faust andFahey (1962) used in this study. Pertinent comments are given belowand include the date, whether FerOa and FeO, Hz(-) and H2O(f ), andAlzOs were determined, impurit ies present, and probable serpentine min-eral. An asterisk indicates that the analysis was used in the statisticaltreatment of the present paper.

*6;1936,0.50 CaO, probably lizardite. *35; 1930, n.d. Fe2O3, chrysotile*10; 1936, HzO lumped, 0.73 CaO, prob- *37;7936, chrysotile.

ably lizardite. 42;1936,0 40 CaO, chrysotile.*72;7936,0.63 CaO, antigorite. 43; 1936, probably antigorite.

13;1936,0.98 CaO, antigorite. x45; 1957, chrysotile.*15; 1957, antigorite. *49;7954, antigorite.*20;1906, HzO lumped,0.?2 CaO, antig- 50; 1931,0 75 total impurity, probably

orite. antigorite.*28;1936, probably lizardite. *51;1947, n.d. FeO, 0.14 NazO, probably

29;1848, n.d. FezOa, H2O lumped, antig- lizardite.

orite. 53; 1885, n d. Fe2O3, n.d. Alroa probably*39; 1857, n.d. FerOr, H2O lumped, antig- chrysotile.

or i te. 54; 1931, n.d. Fe2O3, n.d. AlrOe,0.40 tota l33; 1954, sixJayer orthoserpentine. impurity, probably chrysotile.

S ERPEN T I N E " POLV MORP II S'' 21s

63;1931,0.43 NarO and 0.19 K2O, prob-

ably antigorite.*64; 7957, chrysotile.*65; 1957, chrysotile.+67;1936,1.41 CaO and 4.54 CO2, chryso-

tile.70;1906, n.d. FeO, HzO lumped, prob-

ably chrysotile.7 l ;1931,n.d. FeO, n.d. Al2O3, probably

chrysotile.75;1930, H2O lumped,055 tota l impu-

rity, chrysotile.76;1906, n.d. FeO, chrysotile.*78; 1856, n.d. FezOr, I{2O lumped, prob-

ably antigorite.

79; t956, chrysctile.*86; 1930,0.35 CaO, chrysotile.

89; 1910, lumped FeO-FezOa, and H:O,

chrysotile.*97; 7957 , chrysotile.*94, tgl0,lumped FeO-FerOa and HzO,

chrysotile.+96

; 1936, chinochrysotile.97;l930,lumped FeO-FerOr and H:O,

average chrysotile.100; 1954, lumped HrO, 1.31 CaO, chryso-

tile.101; 1891, n.d. Fe2O3 Iumped H2O, prob-

ably chrysotile.*102;1936, n.d. AlrQr, labelled antigorite,

probably chrysotile.

1lI; 1930,n.d. Fe2O3, 290 CaO, chryso-tile.

112; 1954, n.d. FeO, six-layer orthoserpen-

tine.

115; 1910, lumped Fe2O3-FeO, n.d. H2O-,

n.d. AlzOa, chrysotile.* 120; 1952, antigorite.* l2 l ;1937, n.d. Fe2O3, n.d. HrOa, chryso-

tile.*129;1930, n.d. FezOr, 0.16 CaO, chryso-

tile.*132;1876, n.d. FeO, H2O lumped, antig-

orite.

*136; 1818, n.d. !'e:Oa, n.d. AlzOa, antig-

orite.*137;1857, n.d. Fe2O3, n.d. AlzOa, chryso-

tile.*146;1951,n.d. FeO, HzO Iumped, lizard-

ite.+147; 1926, n.d. l-eo, 1.25 impurities, chrys-

otile.152; L834, n.d. IrerOa, H2O lumped, chrys-

otile.+194; 1936, n.d. FeeO3, n.d. Al:Oa, 0.58

CaO, chrysotile.*197;1931,n.d. FezOs, n.d. AlzOs, chryso-

tile.203; 1885, n.d. FezOa, H2O lumped, n.d.

AlzOs, chrysctile.204;1897, n.d. F-e2O3, H2O lumped, chrys-

otile.205; 1891, H2O lumped, n.d. Al2Os, chryso-

tile.206; 1883, Fe:OrFeO and H:O lumped,

chrysotile.212;1891, n.d. FeO, H2O lumped, chryso-

tile.217; 1955, n.d. HzO-, chrysotile.

x222; 1957 , chrysotile.243; 1947 , n.d. AlO3, chrysotile.

248;1918, n.d. FezOs, chrysotile.+250; 1918, n.d. FezOr, chrysotile.

251;1918, n.d. FerOa, chrysotile.+260;1890, n.d. FeO, chrysotile.*F-1; 1956; antigorite.+\- -15 ; 1962, antigorite.*F-20; 1956, clinochrysotile.* F -22 ; 1962, clinochrysotile.*F -23 ; 1962, lizardite.* F -24; 1962, clinochrysotile.* F -47 ; 1962, clinoch rysotile.*F -43 ; 1962, Iizardite.a F - 46 ; 19 37, Iizar dite.*F -47 ; 1937, Iizardite.

From Page (1967) the following samples

were used: 19-NI-63A, 38-NZ-62-5, 94-NZ-

62, 19-NI-638, and 14-NI-63A.