Canadian Mineralogist Vol. 17, pp.125-135 (1979)

NEW DATA ON STANNITEAND RELATEDTIN SULFIDEMINERALS

S. A. KISSINS eNP D. R. OWENS Mineral SciencesLaboratoies, CANMBT' Depafiment ol Energy, Mines and Resources,Ottawa, Ontario KIA OGI

AssrRAct INtnoPuctloN

Within the system Cu-Fe-Zn-Sn-S, The first description of stannite, ideally Cu:(Fe,Zn)SnSa, Cug(Zn,Fe)SnSa; rrow- CuzFeSnS4,is generally credited to Klaproth sonits CuuFezSnSe, CUB(Fe,Zn)sSn2S., (L797). Since the recognition of a number of and a number of stannite variants have been "stannites", as first expressed by Ramdohr studied by Gandolfi X-ray camera and electron (1944), much new information has become avail- microprobe. In all the examined samples, the com- able on stannite and related minerals in the sys- pounds are stoichiometric with no significant posi- that possesstetrahedrally tional disorder, a result confirmed by structure tem Cu-Fe-Zn-Sn-S refinements. Despite appreciable (FeZn) and coor.dinatedsulfur atoms. This new information (Zn,Fe) substitutions in stannite and kesterite re- has been summarized by Ramdohr (1960), Moh spectively, observed variations of lattice parameters & Ottemann (1962), LEw 0967), Springer with composition confirm the miscibility gap. "Zin- (1968), Petruk (1973), Kato (1974) and Lee et cian stannite" (Berry & Thompson 1962) is a mix- (1974). present paper complements the 'hn- al. The ture of kesterite with exsolved stannite. The foregoing with new data obtained in the course known phase" of Petruk (1973) is a mixture of of mineralogical studies prior to crystal-struc- powder pattertrs, kesterite and stannoidite. X-ray ture refinements at CANMET. Specimenssuit- reflectivity microhardness data are provided for and were obtained: maw- specimens utilized in the structure refinements of able for the refinements kes- (Szymariski 1976) and stannite and sonite (Szymafrski L976), stannite and kesterite (Hall et al. 1978). terite (Hall et al. 1978); however, the miner- alogical study was expanded to tackle a num- ber of other problems. Sorvrvrerns Figure la illustrates the variable metal con- tents and formulae of the minerals in the On a 6tudi6, au moyen de la chambre d rayons Cu-Fe*Zn-Sn-S. The diagram does not par microsonde, les phases suivantes system X Gandolfi et the minerals would systBme Cu-Fe--Zn -Sn-S: statrnite Cuz(Fe,- show the metal: ratios; du were Zn)SnSa, kesterite Cue(Zn,Fe)SnSa, mawsonite not lie in the same plane if a sulfur apex Cu6Fe2SnSs, stannoidite Cus(Fe,Zn)rSnfi2, ainsi added. Figure lb illustrates the ranges in Cu/ que quelques variantes de stannite. Toutes sont (Cu * Sn) vs. Fe/ (Fe f Zn) ratios of the min- stoechiom6triques, pratiquement sans aucun d6sor- erals. The most -rich mineral is maw- drs de position, ce que confirme I'affinement des sonite CuoFezSnSe(Markham & Lawrence 1965). structures. Quoique les substitutions (Fe,Zn) de la The original formula' CuuFerSnSto,was revised (Zn,Fe) la kesterite soient consid6- stannite et de on the basis of irnproved analyses by L6vy rables, la variation des paramdtres r6ticulaires avec (L967), Springer (1963) and Petruk (1973)' la composition confirme la lacune de miscibilitd. et al, (1973) reported La "zincian stannite" de Berry & Thompson (1962) Although Kachalovskaya est un m6lange de kesterite et de stannite d6mix6e. a mineral with the formula C'uz.aoFeSno.glsa.ot La phaso inconnue de Petruk (1973) est un m6- under the name mawsonite, the analysis totaled lange de kesterite et de stannoidite. On pr6sente 104.3%i therofore, the analysis likely reflects les diagrammes de poudre et des donn6es sur la analytical errors rather than nonstoichiometry. r6flectivit6 et la microduret6 d'6chantillons de maw- Mawsonite, as noted by Markham & Lawrence sonite, de stannite et de kesterite qui ont servi ir and L6w, is obviously equivalent to the "orange (Szymariski Hall l'affinement des structures 1976, bornito" first described by Murdoch (1916) et al. t978). bornites described by a (Traduit par la R6daction) and to some orange number of later workers. Stannoidite was originally considered to be *Present address:&partment of Geology, Lake- Cur(Fe,Zn)fnSe or CusFe:SnSe(Kato t969). head University, Thunder Bay, Ontario P?B 5E1. Kato also suggestedthat stannoidite is equivalent t25 126 THE CANADIAN MINI]RALOCIST

(o) (b)

rMtt€

sl,qnddlls o.8 O |Mlh Cu€FolSnSo

O siomldito C!0(Bln,3 Snase o.7 stmll€

\ g 0.6 O Et@ilo Cu2(F€,Zn)SnS4 a, qrd loslsrlt! Cu2(ZnrFo)SnSa + 5 \ o rhqtoslonn ito \ 0.4 .hodGt@rtl6 Cu2FoSnlSo O (-)f 0.!

o,2

o.l

oo oo o:r 02 o.3 0.4 05 0,6 0.7 o.a m ro Fel.Zn Sn Fe/ffe*znl Flc. l. (a) TriangularCu-(Fe+Zn)-Sn diagramfor mineralsin the systemCu-(Fe*Zn)-Sn-S (after Petruk 1973). This diagram displaysonly the variationsamong the metals;differences in metal:- sulfur ratiosare not shown.(b) Cu/(Cu-fSn) vs Fe/(Fe*Zn) for minerals within the system Cu-(Fe*Zn)-Sn-S (after Petruk 1973). to hexastannite(-stannitc l) of Ramdohr namedhy Orlova ( 1956), can also containap- ( 1960), which was givcn the formula CusFeSnS, preciablc . Pctruk found kcsterite with as (details of analyseswere not provided), and to mrtch as 55 aL% Fe. Thc problcmatic struc- some yelfow stannites (stannite jaune) rJescribcd tural stability relationshipsbetween stannite and by a number of earlier workers. Rccalculatcd kcsteritc are lhe subjectof much of the present analyses of hexastannite by Markham & papef. Lawrence(1965), L6vy (1967) and Boorman& Isostannite,optically isotropic and possibly Abbott (1967), togetherwith the hexastannitc a polymorph of stannite (Claringbull & Hey formula derived by Springer (1968) and thc 1955), sakuraiite,the indium analogueof kes- stannoiditcformula obtainedby Petruk (1973), tcritc (Kato 1965) and rhodostannite(Springer confirm that the correct formula for stannoiditc 1968) will not be discussedin this paper. is Cus(Fe,Zn)rSnaSrz,a composition now ac- cepted by Kato (1974). Kachalovskayaet al. (1973) reported finding stannoiditc with thc Mr'.rnons oF SrUDY formula Cus.or(Fe,Zn) r.gSflS6.na; however, this composition is more likely the result of analy- Obtaining accuratcanalyses was initially di.f- tical error, as their analysis totals only 9'7o/o. ficult because the use of binary sulfide or Previous work summarizedby Petruk (1973) clemental stanclardsoften yielded anorhalottsly indicated that stannoidite ranges in composi- high or low atomic proportions in analyzed tion from CurFc,rSnaSrzto CurFerZnSnaSr:. minerals. Improvement over earlier analysesin Pctruk (1973) describeda mineral from the this laboratory and most literature analyseswas Mount Plcasantdeposit, New Brunswick, with attained by production of synthetic CurFeSnSe the approximate composition CursFeZnrSnsSzaand Cu:ZnSnS.r standards. In each case, the as an "unknown phase".This phasc.resxamincd stoichiometricproportions of the pure elements in the prescntstudy, was found to be a mixturc, were heated for 2O days at 800"C in sealed, as discussedbelow. cvacuated silica tubcs. The tubes were then Stannitehas long bcen known to contain ap- quenchedin ice water and the reaction products preciablezinc, such that its formula might bc wero ground in a mortar. The products of the better written Cus(Fe,Zn)SnSa.Petruk (1973) initial reaction were then placed in a vertical found varicties containing up to 55 at.o/oZn furnace in sealed, evacuatd silica tubes with in the (Fc,Zn) sitcs.Kcsterite, Cuz(Zn,Fe)SnS", sufficient flux of NaCl and KCI ( I : I on molar SULFIDE MINERALS r27 basis) to completely immerse them and heated SreNNrrr exo KEstnnttr to 800oC for 4 days. The final quenchedprod- ucts consisted of CurFeSnSr and CuzZnSnS", Stability relationships between stannite and with traces of SnS. X-ray powder and single- kesterite have an important bearing upon the crystal studies also showed the synthetic prod- characterization of the minerals, as it is neces- ucts to be structurally identical to the natural sary to know whether composition alone is suf- minerals. The synthetic materials were com- ficient to distinguish the two. Experiments by pared with natural stannite and kesterite with Moh (196,0), cited without details but later the microprobe; intensities obtained for CuKcy, amplified (Moh 1975), indicatedcomplete solid SnLa and SKa peaks were identical. solution between the two minerals at 700'C in NaCl-KCl Specimensexamined in this study were anal- in dry systems and at 800'C (1972) the high- yzed on a Materials Analysis Company (MAC) melts. Springer confirmed found a Model 400 electron microbeam analyzer op- temperature solid solution, but he gap erated at 25 kV and 0.03 pA specimen current. miscibility in the CufeSnSo-CuZnSnSn at 680oC on The compositions and homogeneity of the pseudobinarysystem that appeared to -bearing specimenswere determined from data acquired the iron-rich side and extended He des- by collecting counts for 10 s periods from 5 to compositions at lower temperatures. the 680oC in- l0 spots on a grain. Stannites and kesterites ignated the solid solution above the lower tem- were analyzed for Cu, Fe, Sn and S by means version B{uz(Fe,Zn)SnS, and phase In of the CuKa, FeKcr, Snlcu and SKa lines of perature,iron-rich a{ur(Fe,Zn)SnSa. phase diagram, the CusFeSnSrstandard and for Zn using the the solid-solution regions of the parameters of ZnKa line of the CugZnSnSastandard. Maw- Springer found that the lattice 2a=c in sonite was analyzed using CueFeSnS.rand the the two phases were distinct, with c by FeKa, SnIa and SKa lines; copper was deter- B-Cuz(Fe,Z\)SnSr and with 2a exceeding mined using the CuKa line of CurFeSnSnor by averaging the values obtained using CurFeSnSe, synthetic CuSe, synthetic CuFeSs and natural . Copper in stannoidite was deter- mined in the same manner, or by using CurFeSnSealone. as were Fe, Sn and S. The ZnKa peak of synthetic CuZnSnS, or synthetic iron-bearing ZnS was the standard for Zn. Minor Ag, Cd and Mn were determined using AgLa, Cdla and MnKa of the pure metal standards. Indium was determined using InLa *-: .*'*L of synthetic InAs, and Se using SeKa of syn- *# thetic CuSe. The data were reduced by means w***wre of the EMPADR VII program of Rucklidge & Gasparrini (1969). All X-ray powder data were obtained by means of a 1L4.6 mm Gandolfi camera. as its provided best means small sample capacity the *YS of obtaining impurity-free patterns. Filtered s 4@'n CoKa radiation (tr = 1.79021A) was em- ^",._ .@ _$

ployed; d values were also calculated for re- 6#.p.1S & solved CoKa, (tr = 1.788904) and CoKas ; "@*;* de-#* (tr = 1.792784) reflections. Relative inten- parameters , .".* ,q. sitieswere estimatedvisually. Lattice r iF* **@< were obtained by means of the PARAM least- "s- - *- *t R *:s* u squaresrefinement of Stewart et al. (L972). ,,,,,$**-e-*-e-*e*{ t: ! ao 4sss g rffi Reflectanceswere measured in air using a frxlefs$s ,"$.'" Leitz MPE microscope photometer with a ,i -.'.;\, silicon referencestandard (N 2538.42,issued by Ftc. 2. Specimen from Omo, Bolivia (ROM the IMA Commission on Ore Microscopy). E1769, grain 2R) showing stannite core (lighter' Microhardnesseswere determined on a Leitz with ) and kesterite rim (darker). Oil Durimet hardnesstester using 50 g for 15 s, irnmersion. tzg THE CANADIAN MINERALOGIST

0.194 in a{ur(Fe,Zn)SnS.r. The B{ur(Fe,- lapping compositionswith respect to (Fe.Zn) Zn)SnSa phase is apparently isostructural with solid solution in the two minerals in his study kesterite; however, the a{u!(Fe,Zn) SnSaphase, of natural specimens. The foregoing indicates although possessi-nglattice parameters similar to that differentiating stannite and kesterite would those of stannite, differs from stannite in that be difficult both on a compositional and struc- its X-ray powder pattern contains extinctions tural basis in the absenceof additional informa- not permitted in Brockway's (1934) model of tion. the stannite structure. Springer was uncertain Stannile and kesterite in a coarsely crystal- whether the lattice parameters of the a and ll line core-to-rimrelationship (Fig. 2) were used phases converged near the miscibility gap. If ior the structural refinements. Crystal frag- a-Cue(Fe,Zn)SnSr is equivalent to stannite, as ments extracted from the field of view in Fig- was assumed by Harris & Owens (1972), ure 2 provided Gandolfi X-ray data which Petruk (L973) and Moh (1975), then clearly differentiated the two minerals, and Springer's (L972) solvus implies the existence these fragrnents ultimately were used in the of stannite and kesterite with identical composi- structural work (Hall et al, 1978), The powder tions. Petruk (1973) found a range of over- patterns are compared with those of synthetic

XABI.E I. X-NAY POWDER DII'FRACIION DATA FOR STANNITE AND KSSTERITE

Syrthetlc Cu"F€SnS, Stannlter ;ynthetlc Cu,ZnSnS,' Kesterlter (80o'c)' Roil 81769, Cr 2!(3 (800"cr - RoME1769, Gr 2Rl2) q.5.4432r 0.00llA a€5.449I 0.0024 r"5.4339!0.0009A4"5.427t 0.001A c.10.7299! 0.00514 . o.ooal ].lo.aozgto.ootaA O.ooSi !"to.zsz "-.to.eft. lrt, d^r- d--, ^ t/ I d^!- d-..- tl. rkl tt \l r.89 14.6v 4.& tl2 J.tl 13 ll |3.r3 3.13 l0 t12 3.13 3.14 l0 3.13 3.13 l0 r20. )l3 3.00 ,9i 13.01 3.00 r 2,715 2,717 6 2.701 2.712 3 t20 2,723 721 : 12.718 2.726 \ )04r 2 1201 't,920 r04 2.678 a.t83 2.681 2.6se 1.921 9 1.913 1.918 5 t22 ?.427 2.t27 I | 124' 21 2,369 2 374 i ln36 L3.a - '1.640 '14 11 r.638 B I .53$ 1.636 7 2.205 l6r '| ,. 006 )1, I 12.202 -T t24 .567 1.569 I I .571 1.566 t. 140r 't.358 Il5 I .983 196 l r.ool ,-oor 1.354 I .359 2 r.356 I t20 1,922 ,25 t___ )08, t24 r.908 illI r .sra r .9r4 7 132r 1.246 1.247 4 1,245 1.245 3 r31r I 1.784 { 189 r I t06' 788 r40 't.2t3 t.640 t39 | ;; t44 r.213 I 't l,-, t28 6, ,623 tl'!!l 4 ' ;ft' lr.ozz t44\ 1.110 1.109 5 1.108 t.t07 3 t24 t64 1 r.563 1.566 r tza' 34 449 449 l I 52 '1.047 389 t0t r36 1.045 5 t.045 I .044 3 r40 501 r .363 1.363 r .1.r 0. '40. t08 341 341 1,342 L344 2 0.9600 0.9605 4 0.9589 0.95& 1 4lr t48J 310 { ll0 310 t52 p.9178 '2 0.9186 0.9185 6 0.9169:1 2 27 29 297 '1.2731.303 I .3C0 56 !.9178 0.9169o2 I - 1.269 \ t 1n | lz4' ,aa 1.250 1.250 | 240 t.240 )f t.uz tl'.1!l 6 , ^,^ .1.219 i40r | .215 217 ''"'" t44' 214 I 1.215 t * Lattlce parametersfrcm stroctlre t25 t.?m 203 '1.109I .209 1,206 \ reflnsents of Hall g!91. (1978). t44{oI 1.107 t08 '1.110 1.110 3 Errcr tems ln all cases are standard s2 t.109 t08 1.110 t1 deviations. t.t00 100 i 1.102 I .103 3 | .101 t00 l 1.102 1.103 t 29' l .070 )7L l 52{"I | ,047 A7 l r.048 r.049 I 82 1,047 )47 ) 153.'cr t.043 )42 1.044 1.043 I r+1" o, |,042, 141 I 1.043 1.043 t1 t.034 I .038 l.036 2 - t.033 )37 J 1.037 I .036 ta r.2.10 ).9987 )942 l ).9718' )727 I ,40{or ).9622 ,.*t ; 42 ).9617 )622 l 0.9574 "*,0.9571 3 88{oI ).9557 s2 0.9573 0.9571 r r52(ql ).9198 )197 : 0.9214 0.92t0 2 d2 ).9200 )197 1 ).9167 n66 t 0.9179 0.9182 3 a2 ).9169 0.9177 0.9182 2 .3.1o{o I ).9105 n06 I 0.9125 0.9125 4 c2 ).9106 )106 i 0.9123 0.9't25 2 160 -t 0.9087 0.9085 ta 44 ).9058 tosl r48 .O.gO:OO.gO:O ).902r )013 i to.9o3z o,9o3oa;l",2 TIN SULFIDE MINERALS t29

TAELE 2. TLECTRON}IISROPROAE AMLYSBS OT STANMTE AND TSSTERIE

ltelght per cent At@lc DroDottlora SepLe aod locallty lotaX cEf6Eza6 STNNIM 1. &u!o, Bollvla 29,2 -- rl.3 --- r.8 -- 28.0 29.7 100.0 1.99 0.88 0.12 L.02 4.0{ ROll E1769, Cralu 6-2b 2. Orulo, Bollela 29.5 --- 10.5 - 2.7 0.43 27.8 29.9 r00.8 1.99 0.81 0.18 0,02 f.oo 4.0( Roil 81769, Gretd 2R (3) 3. Levack west olne, Sudbury, 29.a -- 10.8 --- 2,7 0,04 2A.0 2?.7 101.0 2.01 0.83 0.18 0.00 1.01 3.9t ht., CAI{WT conceDtrate 4. Orulo, b1lvta 29.6 -* 10.8i -- 2.2t O.tL 27.7 0.03 29.7 100.1 2.01 0.86 0.14 0,00 1.01 0.00 4.(X cSC 14738, crain 3 5. Oruto, Bollvla, San Jos€ 29.5 n.d. 11.9 ___ 1.5 _ 26.2*1 1.33ri 30,3 100.8 1.98 0,91 0.10 0.r4 0.054.0: 6tn€, Roil M190349 6. le orshaDler deposlt 29.1 0.15 11,5 0.10 2.3 n.d. 27,5 o.d. 29.9 r.00.6 1.96 0.88 0.01 0,15 1,00 4.01 (@teray, 8.c., RU V8.lA

KESTERITE 7. tuuto, tullvia 29.L -- 3.7 -* LL.r O.22 27.3 29'7 101.1 1.98 0.73 0.29 0.01 0.99 4.01 RoM 81769, craln 2R (2) 8. Zl6sa1d, bhsla, Czech. 30.0 -- 6.5 0.02 7.8 0.r7 26.J 0.07 29.9 101.0 2.03 0.50 0.00 0,51 0.01 0.96 0.@ 4.q IISNUC5233, eraln 1 9. oruro, tollala t-01.6 L,96 0.27 0.76 0.01 0.99 4.0i Rou 11769, crsln 2R 10. zlndseld, tuh@la, Cz6ch. 30.2 --- 4.1 0.09 9.A 0.25 26.0 0.11 29.4 100.0 2.O7 0.32 0.0r 0.65 0.0r 0,95 0.00 3.9! gSNl{ q5233, Ctaln A i1. zrnnetd, }oh@le, czech. 29.7 -- 6.3 0.08 7.5 0.L7 26.3 0.04 29.6 99.7 2.0J 0.49 0.U) 0.50 0.00 0.95 0.00 4.0: USNil C5233, cratn B 12. lfugo Dlne, (eystooe, 29.0 ---e 2.3 0.03 10,9 L.67 27.1 29.7 100.7 1.99 0.18 0.00 0.73 0,07 1.00 4.4) s. Dakota, sDs!{&T 5099 r Avetege valuesi sll.ght vatiatlon zo F 1.7 to 2.72 6na Fe o U.2 to 10.22 {t. trAvela8e laluesi s118ht verlatlon Itr F 0.54 to 2,047 and Sn'27.4 to 25.22 ft. @ Stlve! could lot be detehloed because of secotrdary f1lorescdce fl6 nlnute locluslons of an 61Bdent1f,1ed alleei-batlng Phaae. Sp€clden no. 5 tas taten fr@ the tuple used ln derlvlDg Berly 0 ThoEpBoa'E (1962) pattefr fo! sta@lte (rc. 69). thfu 16 th€ fj.rat eDalysls of thla apeclaen. SElthsnleo o.d. aldotes dot alelecteal (1lolt of derectloa I O.02Z rt.); ROlts tuyal htallo hse@i USW- Untted States Natloml !iise@,- - Insttrutloai cSC F Ceologlcel Sutrey of &frda; SDSWT = ituse@ of G6ology, South Dakota of Ulnes E TelEologyi n.f. R. lrdugan' CSc. be determined only by Cu,FeSnSa and CuZnSnSa from this study in tetragonal symmetry can example, (020) and Table 1. Compositional data for the natural singli-crystal methods. For diffraction couplet specimensare provided in Table 2 and reflec- (OM) form a closely spaced in kesterite' A tances in Table 3. Misrohardness indentations in stannite and are unresolved and unresolvedcouplets could not be obtained, as grain mounts con- nu.mberof such resolved from kesterite' taining the minerals fractured excessively. clearly distinguish stannite on Powder-pattern differences between stannite To determine the effect of composition and kesterite, and kesterite are subtle but distinct. Both are the lattice parameters of stannite worldwide tetragonal with the same permitted reflections, carefully selected specimens from X-rayed h+k+l - Zni however, kesterite is strongly localities were analyzed (Table 2), and pseudocubic. Lattice parameters derived in the with a Gandolfi camera. The cell dimensions indexing with a structural refinements (Hall et a/. 1978) show oI kesterite were refined by parameter c. This that stannite 2a exceedsc by about 0.lA where- pseudocubic cell of lattice = so that the as kesterite c exceeds 2a by only 0.01A. fhe procedure t}ten assumes2a c, with the difference between 2a and c in kesterite cannot iesults are useful only for comparison shows be determined by powder methods, and its lattice parameters of stannite. Figure 3 2a and c v,r. composition of the (Fe * Zt) sites in the stannites and kesterites from Table TABLE3. REFLECTANCESANDltlICRo-INDENTATIoN HARDNESS OF STANNITE,KEsTERITE AND IIAIISONITE 2. Parameters of the pure' synthetic end-mem- bers from this study are also included. Minor Wavelenqth(nm) 470 545 589 650 amounts of Mn have been added to Fe and stannlte' oruro' Bollvia .Ro 26.1 ?7,2 27.4 ?7.4 (R0ME1769, grain 2R[3]) RA 27.6 28.0. 28.2 27.6 Cd to Zn in normalizing the atomic contents of KesterJte,oruro, Bolivia ,.o 24.3 23.8 23.8 24.7 the (Fe f Zn) sites to 1.000. (Ro|'tEl76e' grain 2R[2]) These studies of well-characterizedspecimens I,lawsonite,Ikuno mlne' ao 19.5 22.6 24.5 28.3 show that stannite and kesterite are structurally Japan(Nli'lNH 122102) 14.9 20,3 24.9 31.6 distinct (Fig. 3). Lattice parameters show no !{awsonlte,Kidd creek .Ro 21,2 24.0 25.6 ?9.6 mine,Ontario 8c 17.7 22.8 28.3 34.5 tendency to converge as a function of solid (RrrrQ 74-68lul) solution, although the pararneters of stannite l4awsonlte,Kidd Creekmine specimen:mlcro-lndenting increase slightly with increasing solid soltrtion hardness (rneanof thr€e nEasurements)VHN59, 240 I 19 of Zn. and those of kesterite decreaseslightly 130 THB CANADIAN MINERALOGIST

E Typicolermr limifs qt lo-

o tr

o< .g

q, o E o o o- c, .o 5

o'soo Fe(+Mn ) : t.ooo zn (+ cd): t.ooo Conlenlsof the (Fe +Zn) Site Frc. 3. A plot of 2a and c lattice parameters vs. the composition of the (Fe-FZn) sites in staDnite and kesterite. Sample numbers correspond to those in Table 2; synthetic end-members are from this study. Mn has been added to Fe and Cd to Zn and the atoms in the (Fe*Zn) position have been normalized to 1.000. Solid symbols are the synthetic end-members. with increased Fe in solid solution. Figure 3 previously suspected, perhaps nearly as com- does not purport to illustrate the entire range mon as stannite. Kesterite should be suspected of solid solution of both minerals; more ex- where isotropic or nearly isotropic 'ostannitesn' tensive solubilities of Fe and Zn in kesterite are noted. and stannite, respectively, have been reported Although stannite and kesterite may be dis- in the literature. However, the results shown tinguished in polished section, particularly in here do indicate a miscibility gap between the lreshly polished sections under oil immersion, two minerals, and suggest that they possess the etching technique employed by Harris & di.fferent crystal structures. The latter conclu- Owens (1972) was found to be extremely use- sion has been confirmed by Hall et al. (1978), ful in differentiating the two minerals in inter- who refined the structure of stannite in space growths. A 1:1 solution of HNOg etchesstan- group I42m and kesterite 14. nite and attacks kesterite much more slowly. Also demonstrated by these well-character- Caution is necessaryin interpreting the etched ized specimensis that neither stannite nor kes- section. as the etchant also attacks twinned terite exhibits nonstoichiornetry beyond -+57o crystals differentially. in any alomic position in the idealized formuia Cur(Fe,Zn)SnSe. The small divergencesare at- THr Pnoarsvr op STaNNITEVARTANTs tributed to analytical error. These data strongly support the structural model of Brockway Zincian stannite (1934) Ior stannite, 1.e.,ordered sites in space group 142m, and further indicate that the con- Berry & Thompson (1962) applied the term tents of the atomic positions in kesterite are "zincian stannite" to a specimen from the ordered. Snowflake mine, Revelstoke, British Columbia. The detection of kesterite, often unnoted or They noted that the X-ray pattern (No. 70) misidentified, in a number of museum speci- of this mineral differed from that of stannite mens studied in this investigation indicates that and required difderent cell dimensions. The the mineral is probably more common than PDF listing (21-883) presently applies the TIN SULFIDE MINERALS 131

Berry & Thompson data to kesterite, so that TABLE4. ELECTRONMICROPROBE NALYSIS OT "ZINCIAIISTAITNITE'T identity of zincian stannite .and kesterite has been assumed. Element Kest€nite .(host) -!fa'|! j.te_0_CnF_X-ee) Cu 29,0 ut, % 29.3 ut. % The Berry & Thompson specimen (UT R218) Ag 0.42 0.1I that gave pattern No. 70 was found to consist Fe 4.4 8.2 Zn 9.6 of massive kesterite with copious lamellae of 0.10. 0.28 exsolved stannite (Fig. 4). Analyses of the Mn n.d.' n.d.* Sn 27.0 at,l two minerals are given in Table 4. The powder ln 0.13 0.'t2 pattern is that of kesterite with several reflec- 29,2 29.5 tions of stannite. The kesterite reflections alone 99.8 t00l * yield lattice parameters intermediate to those t unlverslty of Torontocollection, UTMl8; not detected possibly (i.e., < 0.02 wt. %). Formulaeare basedon a totai of eight of stannite dnd kesterite, becausestan- atons. Kesterlte host: ( (snt - nite and kesterite reflections are not resolved cu2.99Aes.92)12. oz( Zno.64Feo.35)ro. gg .ooIno.0l )rl ,ot in a mixture o,f the two minerals, even though 53.99i stannite larFllae: their lattice parameters differ slightly. The cuz.o0( F"0.642n0. socdo. ot )rt .0tsno.9953.99 effect on unresolved reflections would be to shift d spacingstowards a mean value. The Berry & Thompson X-ray powder pattern not yield the correct lattice parameters for (No. 70) is therefore suspectoas it may contain kesterite. Preferred data are those obtained reflections attributable to stannite and likelv will either from topotype kesterite by Ivanov & Pyatenko (1959), or from the Oruro (Bolivia) specimen (No. 7) used in this study and in the refinement of the kesterite structure. Petruk (1973) employed the term "zincian stannite" for stannites containing from 40 to 55 at./o Zn in the (Fe * Zn) Sites.This usage is in accord with mineralogical practice but it conflicts with the prior usage of Berry & !$l! (1962). !rl! Thornpson As well, Petruk found a)'::. significant nonstoichiometry in his specimens in that they contained excess (Fe * Zn) and deficiencies in Cu or (Sn * In) or both. One of us (D.R.O.), who was Petruk's analyst,be- lieves that the deficiencies are analytical and aross principally from the use of binary sulfide and elemental standards. However. if Petruk's zincian stannites are truly nonstoichiometric, they are likely not isostructural with stannite :*t1. - or kesterite and therefore represent some here- tofore undescribed species. Unfortunately, t;1, Petruk's specimens are too small to be useful for further study. In any event, the term "zin- cian stannite" probably should be avoided in view of the conflicting usages to which it ij:;', has been subjected.

Ferrian kesterite # Petruk (1973) applied the term fenian kesterite to kesterite containing 25 to 55 at, Vo Fe in the (Fe *Zn) sites. This range seemsto be normal, rfif!{{lL;r$.}$t}crsfls f::::..1.::sd,+:.r. and complete solid solution to the CuZnSnSa Frc. 4. Specimen from Snowflake rnine, Revelstoke, end-member is well established.Petruk's ferrian British (UT R218), identicalto zincian Columbia kesterito differs slightly in reflectivity and sub- stannite of Berry & Thompson (1962). The kes- etched (l:1 HNq) left side shows exsolved stantially in microhardness from low-iron lamellae of stannite (etched) in a kesterite host terite. The most iron-rich kesterites reported (unetched). Crossednicols, oil immersion. in this study (Nos. 8 & 11, Table 2 & Fig. 3) t32 THE CANADIAN MINEMLOGIST

aro similar in composition to those reported with respect to the electron beam. However, in by Petruk. The problems relating to these high- the course of the study, an improved X 100 iron compositions and the role of indium will objective with a flatter field of view was ob- be treated in a subsequentpaper. tained and the grain was re-examined. The grain consists of an extremely fine, oriented, "Unknown phose" lamellar intergrowth of stannoidite and kesterite (Fig. 5). The apparent composition of the mix- A mineral compositionally intermediate be- ture can be representedby the following egua- tween stannoidite and ferrian kesterite was tion: CuaFeZnSneSra(high-Zn stannoidite) * reporred by Petruk (1973). His polished sec- 3CuZno.ozFeo.sgSnsa(ferrian kesterite) = tion, No. 52-523, was borrowed and the grain CureFeZngSnrS:a.Ramdohr (1944) shows sim- illustrated in his Figure 11 was relocated. Migro- ilar intergrowths, although somewhat coarser, probe analysis yielded results similar to those in material from Zinnwald. He identified the reported by Petruk and indicated homogeneity two components as stannite I and II. Similar textures were found in material from Zinnwald in the present study. The two minerals are stannoidite and kesterite. The "unknown phase" t** of Petruk (1973) is an example of a "micro- 'r.'. probe-homogeneous intergrowth" that occurs not too infrequently, though rarely expressed as a warning in literature (Scott 1976).

SteNNonttB

Stannoidite from two localities was analyzed (Table 5). The mineral seems to be stoichio- metric Cue(Fe,Zn)gSnsSrr,in agreement with the structural refinement of Kudoh & Tak6uchi (t976), who determined that the unit cell of stannoidite contains 25 atoms with the accapted formula. The ratio Fe/Zn in the presentanalyses ranges from 2:1 to 3:0, in agreement with earlier observations as well as those of Yama. naka & Kato (1976). Their Miissbauer study showed stannoidite to have the ionic formula Qgl +spge+rpgs+Sna+u,S2-rc.Zinc apparently may substitute only for Fe2+, giving rise to the observed Fe/Zn ratio in the mineral.

TABLE5. ELECTRONMICROPROBE ANALYSES OFSTANIIOIDITE Element Ikuno nine, Hyogo Kidd Creeknine, Prefecture, ilapan 0ntario Cu 38.5 wt. % 38.8 wt. % Fe ll.5 8.5 7n 1.6 4.5 5n 18.9 18.0 29.3 29.1 (a * l.l '100.0 99.8 'trnknown * Frc. 5. The phase" of Petruk (1973), Not detennined.Formulae listed beloware basedon ao intergrowth of stannoidite and kesterite a total of 25 atoms.SpecinEn from the lkuno mlne is NMNHI08319 (Smlthsonian Institution collection): (centre). Individual lamellae are less than I s,m c' g'G go' speciren f rcm thick. The grain is rimmed by chalcopyrite I . z. agzn'.33) 23. 'zsnz. ogst t . " (R.I. (cp, white), which also occurs the Kidd Creekmine is TQ74-5601101 Thorpe, as oriented kological Surveyof Canada): Crg.OO(F.2.OlZnO.gl)- lamellae in the surrounding (sl, dark erey). The light grey mineral is (ten). r2. gzsnl. gg(slr . gtseo. r a)rr z. os' TIN SULFIDE MINERALS 133

MewsoNrts have produced the d - 2.098 A reflection noted here, but filtration problems were not previ- Both the formula, as discussed earlier. and the structure of mawsonite have been sutjects of controversy. The formula CusFesSnSowas TABI,E 6. POWDBR X.RAY DIFF'RACTION DATA FOR I4AWSONITE confirmed in the present study, analyseshaving I been given previously by Szymairski (1976), !4arsoni te l'la$son ite Mavsonite The non-cubic structure of mawsonite is in- dob" r/rroo dob. r/rLoo dob" r/rto d..1" hkl dicated by its very strong anisotropy. Attempts '7.6 by Markham & Lawrence (1965) at indexing 7.62 010 20 t0 5.3 I s,4 110 the powder pattern led to a pseudocubic solu- l. 5. 4 001 4.37 tion. Yamanaka & Kato (1976) proposed 20 4.38 4.38 0lI that 10 3.80 3.70 f 3,80 020 tho structure l:.go rlr was tetragonal with space group 10 3. 378 4 3.40 L20 142m, 1422 or 14122, a 1O.745, c 3.09 r00 3. 099 100 3. r.0 10 3.10 027 -I4mm, t0 10 2.88 4 2,87 r2L tO,7lLA. Szymariski (1976), however, refined 2.680 2.654 I 2.69 220 l,2.68 002 the structure in space group P4m2, with a 2.s2 '/, 2. s3 0L2 ( 2.40 I30 1.6O3,c 5.3584. 10 2.40L I 2.4L 3 I 2.40 22L Prior to Szy.mafiski's structural refinement, \ 2.39 \12 l0 2.30 2 2.29 031 the specimenIRIT, TQ74-681( I ) I from the Kidd 2.185 2.L9 I 2,L9 022 Creek 2.094 2.09 ,/, 2.LL 230 mine was examined mineralogically. The tlgez 1.958 | /: L,962 2t microhardness and reflectivity of the mineral I.895 80 l. 899 r.899 7 I 1.901 040 1,1.898 222 were measured and the latter property com- I .788 L.791 3 L.790 2 I r.792 330 ( 1.789 L32 pared with that of mawsonite from the Ikuno L;739 2 1.74t 2 !.7 44 r4l mine (Table (1976) 1. rtl8 80 1.620 40 L.6Ls 6 IL.621 24r 3). Szymaiski provided a t1.617 023 '/ calculated powder pattern of mawsonite; an 1.5s4 z 1.58L L23 L.547 t0 L.549 7 1.s50 042 indexed measured pattern given in Table 6 is ( L.463 051 1 .460 1.463 L.462 2 I r.463 34L compared with data obtained previously by ( L.460 033 , Markham & Lawrence (1965) and Yamanaka 1.439 / 1.435 242 , " s 25r L.362 / I1.36(r.363 & Kato (1976). Although the agreementamong " 233 1.343 20 1 .344 I 1.344 440 the patterns is good, Szymaiski (1976) ques- ( 1.340 004 tioned whether some of the reflections observed t. 3t8 1.319 014 r I.304 530 by Yamanaka & Kato (1976) were perhaps .l 1.303 L52 L1.300 rr4 due to impurilies. Although Yamanaka's & 1. 233 10 1.213 ,/z I r.233 061 t 1.231 243 Kato's reflections at d = 7.62, 1.318 and (I.202 260 l3O2A 5 J 1.201 442 are indexable in Szymaiski's cell as \1.199 224 (010), (014) and (M1,152), respecrively, rr.r59 451 1.155 t/" .l 1.1s8 343 Szymafski concluded from his structural work I r.r58 053 \ 1.146 062 that the intensities of these reflections should (r.o97 1. 096 1.095 7 262 be too weak to be observed. However, com- tr.ogs o44 fI.035 461 parison of intensities on the Gandolfi film with i r..034 063 rt-.03r o25 those of Szymaiski indicates that all but (014) (L025 27L t/" L.023 1 L,024 163 are observable. The intensity of (014) is very \1.022 125 0.9983 370 weak according to Szymafiskfs data; but the r/z f 0.9967 1 0.9979 L72 observed reflection reported by Yamanaka & I 0.9954 225 o.9s67 r/" I0.9570 363 Kato is too close to the calculated d value to (u.trtJ z5) be (012) 0.9491 5 I0.9504 080 fortuitous. The reflection, as well, t 0. 9488 444 was observed in this study, although Szymafrski 0.9360 I 0.9355 372 0.9291 2 0.9288 47L omitted tiis reflection as too weak to be ob- 0.9079 2 0.9079 453 0. 9066 4 0.9065ar 245 served. The 2.4624 reflection observed by 0.9068 3 0.9055u2 245 Ya,manaka & Kato does not agree well with

any observed in this study or with the data 1. ldawsonite. Mt. LyelL, Ta€@ia, Auetralla, (Markhil of Szymaiski, although it is nearest to (012). & I,aer6nc@ L965), DebyE-sshelrer (co) 2. l{awsonlte, Akenobe alne' Hyogo Plefeclure' 'tapil, The (230) reflection was not reported by (YaMnaj

ously observed with our X-ray camera. As Rnnr,nsNcrs well, the reflections appear in other powder patterns and in the calculated pattern using Brnnv, L. G. & TnoursoN, R. M. (1962): X-ray CuKa radiation (J. T. Szymafiski,pers. comm.). powder data for the ore minerals: the Peacock Markham & Lawrence and Yamanaka & Kato atlas. Geol. Soc, Amer. Mem. 85, observeda weak reflection at d = 3.34 and BoonveN, R. S. & Anaom, D. (1967): Indium 3.3784, respectively. Szymafiski stated that this in co-existing minerals from the Mount Pleasant reflection could not be indexed on his cell, tin deposit. Can. Mineral, 9, 166-179. although the calculated value of d : 3.4O4 Bnocrwev, L. O. (1934): The for the (12O)reflection is closestto their values. of stannite, CuaFeSnSr.Z. Krist. 89, 43+441. Although (120) was not observedin the present Cr.enrNcrur-r.,G. F. & Hsy, M. H. (1955): Stan- study, it seems possible that it is an X-ray re- nite and isostannite. Mineral, Soc. London, No- flection of mawsonite and that neither the tice 9l(2). (See Mincral. Abstr, L8, 31, 1956). pattern of Markham & Lawrence nor that of Helr, S. R. Szvr"re(srr, I. T. & Srpwenr, J. M. Yamanako & Kato contains reflections at- (1978): Kesterite, Cuz(Zn,Fe)SnS4,and stannite, tributable to impurities. Cur(Fe,Zn)SnS4, structurally similar but distinct The strongly pseudocubic X-ray powder pat- minerals. Can. Mineral, L6, l3l-137. tern of mawsonite is explicable if. d = 2c Hmnrs, D. C. & OwENs, D. R. (1972): A stan- in terms of the unit cell and space group given nit€-kesterite exsolution from British Columbia. by Szymaiski (1976). Thus, for reflections Can, MinaraL ll, 531-534. such as (110) and (0Ol) in which (h, + IvaNov, V. V. & Pverrrrro, Yu. A. (1959): On &'),rto,= 2Pcoor>and (h2 * &'),oor,: 2fnnr, the so-called kesterite. Zap. Vses. Mineral, the two reflections will be nearly superimposed Obshchest. 88, 165-168 (in Russ.). and unresolved. Although P4m2 has no ex- KAcHALovsKAyA, V. M, Osrov, B. S., Kuroev, tinction requirements, the previous condition V. A., Kosr,ove, E. V. & Besove, G. V. (1973): greatly reduces the number of discretely ob- Mawsonite and stannoidite from the ores servable reflections. of the Urup deposit. /n Mineral. Paragenezisy Mineral. Rud. Mestorozhd (P. M. Tamarinov, ed.). Nauka, l*ninerad (in Russ.). AcKNowLEDGEMENTs Kero, A. (1965): Sakuraiite, a new mineral. Chigaku Kenkyu Q. Study Geosci. lapan) Sakvrai Vol., l-5 (in Jap.; abstr. in Amer. Mineral, 53, Tho authors thank Dr. D. C. Harris. r42r). CANMET, for providing impetus and guidance (1969): Stannoidite, Cur(Fe,Zn)2SnSg,a for the study. Valuable discussionswere held new stanniteJike mineral from the Konjo Mine, with Drs. L. J. Cabri, S. R. Hall, W. Petruk Okayama Prefecture, lapan. Nat. Sci. Museum and J. T'. Szymaiski, all of CANMET. The Bull. t2, 165-172. following personnel at CANMET provided tech- (1974): Changes in compositions of sul- nical assistance:R. G. Pinard (photography), phide minerals in the Cu-(FeZn)-(Sn,In) sys- E. J. Murray (powder X-ray techniques), J. tem. Kobutsugaku Zasshi. (t. Mineral. Soc. M. Stewart (single-crystal X-ray techniques), tapan) LL(2), 145-153 Gn Jap.). J. H. G. Laflamme (polished section prepara- KLApRorr{, M. H. (1797): Beitriige sur Chemischen tion and crystal synthesis), Drs. S. R. Hall and Kenntnis der Mineralkbrper. 2. Chetnische Un- D. C. Harris (data reduction), Dr. T. T. Chen tersuchungen des Zinnkieses. Posen u. Berlin. (reflectivity and microhardness measurements). Kuoort, Y. & Txfucrn, Y, (t976). The srper- We also thank the following for supplying structure of stannoidite. Z, Krist, LU, 145-L64. specimens: Drs. R. I. Thorpe and R, Mulligan, Lrs, M. S., Ternxoucrn, S. & Iuu, H, (1974): Geological Survey of Canada, Drs. J. A. Occurrence and paragenesis of the Cu-Fe-Sn-S Mandarino and F. J. Wicks, Royal Ontario minerals with reference to stannite, stannoidite Museu,m, Dr. E. W. Nuffield, University of and mawsonite. Kobutsugaku Zasshi (1. Mineral. Toronto, W. L. Roberts, South Dakota School Soc.lapan') 11(2), 155-165(in lap.). of Mines and Teshnology, and Dr. J. S. White, Lfw, C. (1967)t Contribution i la min6ralogie Smithsonian Institution. The manuscript bene: deo sulfures de cuiwe du type CuoXSr. Bzr. fited from critical reading by Dr. J. L. Jambor, Rech. G6ol. Minidres Mtm. 64. CANMET. (S.A.K.) One of us received $up- MenrHAM, N. L. & IdwnsxcE, L. I. (1965): port from the National Research Council of Mawsonite, a new copper-iron-tin sul,phide from Canada in the form of a postdoctoral fellow- Mt. Lyell, and Tingh4 New , South ship tenable at CANMET. Wales. Amer. Mineral. 50, 900-90E. TIN SULFIDE MINERALS 135

MoH, G. H. (1960): Experimentelle Unter- tron microprobe analytical dzta reduction suchungen an Zinnkiesen und Analogen Ger- (EMPADR YII). Dep. Geol. Univ. Toronto. maniumverbindungen. Neues Jahrb, Mineral. Scon, J. D. (1976). A microprobe-homogeneous Abh.94. Ll25-tt46. intergrowth of and matildite from the (L975): Tin-containing mineral systems. Nipissing mine, Cobalt, Ontario. Can. Mineral, II. Phase relations and mineral assemblage$in 14. 182-184. Cu-Fe-Zn-Sn-S system. Chem. Erde 84, L-61. Sr'nrNor& G. (1968): Electron probe analyses of & OrrsMANN, I. (1962): Neue Unter- stannite and related tin minerals. Mincral. Mag. suchungen an Zinnkiesen und Zinnkiesverwand- 36, 1045-1051. ten. Neues lahrb. Mineral. Abh. 99. l-28. (1972): The PseudobinarY system Munpocn, J. ( 1916) : Microscopical Determina- CugFeSnSa-CurZnSnSa and its mineralogical sig- tion of the Opaque Mineralst An Aid to the nificance. Can. MineraL ll, 535-541. Study ol Ores. McGraw-Hill, New York. Srswenr, J. M., Knucsr, G. J., AnuoN, H. L., Orrove, Z. V. (1956): Collection of chemical DrcKrNsoN, C. H. & Hetr-, S. R. (1972): The analyses of ores and minerals from mineral de- X-ray system of crystallographic programs for posits in the northeastern USSR. Trudy Vses. any computer having a PIDGIN FORTRAN Magadansk Nauchno-Issled. Inst. Magadan 2, 76 compiler. Univ. MaryIand Computer Sci. Center (in Russ.; abstr. in Am.er. Mineral' 48, 1222' Tech. Rep. TR-L92, 1223). Szvr'rel(srr, J. T. (1976): The crystdl structure PBrnuK W. (1973): Tin sulphides from the de- of mawsonite, Cu6Fe2SnSs.Can. Mineral, L4' posit of Brunswick Tin Mines Limited. Ccn. 529-535. Mineral. L2, 46-54. YlueNere, T. & Kero, A. (1976): \4iissbauer 57Fe lrsSn RAMDoHR,P. (L944)t Ztm Tinnkiesproblem. lDlr. effect study of and in stannite, stao- Preuss. Akad. Wiss., Math,-nat, KL 4, l-30. noidito and mawsonite. Amer. Mineral, 6t, 260- (1960): Die Erzmineralien und ihre Ver' 265. wachsungen. (3rd ed). Akademie-Verlag, Berlin. Received July 1978: revised manuscript accepted RucKLTDGE,I. C. & GAsPARRTM,E. (1969): Blec- September 1978.