Canadian Mineralogist
Yol. 27, pp. 673-688(1989)

THE RELATIVESOF STANNITE IN THE LIGHT OF NEW DATASTEPHEN A. KISSIN
Departmentof Geology,LakeheadUniversity,ThunderBay, OntarioP7B sEI
DE ALTON R. OWENS
Mineral Sciences
Laboratories,CANMET, 555Booth Street,Ottawa,OntarioKIA OGIABSTRAcT

poss€danti peu pr&sla mOmecomposition chimique quela stannite mais qui sont distinctes dansleur structure. On
Two new minerals of approximately the samecomposi- trowe la ferrokesterite dans des filons de sulfures d bortion as that of stannite but differing crystal structureshave dures greisenisdesdans un granite dans le mine de Cligga,
been discovered.Ferrokesterite occursin greisen-bordered d Perranzabuloe, en Cornouaille (Angleterre). C'est un
sulfide veins in granite from the Cligga mine, Perranmin€ral tdtragonal, qui crlstallise dansle groupe spatial,I4,
zabuloe,Cornwall, England, The mineral is tetragopalwith
Z:2: a 5.433, c 10.884A; Sa densit6calculdeest4.490,
space gxoup 14, Z--2; a 5.433 and c 10.884 A; D"ur. et sa duret6 (6chellede Mohs), 4; sa miooduret€ (VHNtm)
4.4% g c:lr-3.Ferrokcterite has hardnessabout 4 Mohs),
est 238. Un clivage distinct est paralldle e { I lOh le min6microhardness(VHNl1g,)238. Cleavageis distinct parallel ral ses6parele long de {001}. Les r6sultatsd'une analyseto {110}, and parting developsparallel to {001}. Results chimique i la microsonde6lectroniquembnenti la formule
pour l'6chantillonof an electron nticroprobe analysis gave the formulaCu1.ee(Feq.67Zno.r:)r1.esSnq.rrSa.92
for the holotype speci- holorypique, ce qui correspond i Cu2(Fe,Zn)SnS4et qui
Cu1.e@es.67Zne.3rs1.6sSne.eSa.02
men, corresponding to Cu2@e,Zn)SnSaand approaching s'approchedu p61eCu2FeSnSa.
Les uois r€flexions les plus
the end-member Cu2FeSnSa.The strongest reflections in
intenses du clich€ de diffraction [d en A(IX&kD] sont:the X-ray powder pattern are: 3.13(10)(ll2), 1.919(6) 3. I 3( 10XI 12), | .919(q(n0,024), et | . I r0(4)Q44,228).La
Q20,024),l.l l0(4) Q44,228).The mineral is a polymorph ferrokesterite est un polymorphe de la stannite et formeof stannite and forms a solid solution with kesterite, of
une solution solideavecla kesterite,dont c'est I'analogue
which it is tlie iron.analog. Petrukite occurs in polymetalferrifbre. La petrukite fait partie d'une association polylic veins associatedwith granitic plutons at the Herb claim,
m6tallique fissurale li6e i des plutons granitiques l) i
CassiarDistrict, British Columbia; the Ikuno mine, Hyogo
I'indice de Herb, dansle district de Cassiar,en ColombiePrefecture,Japan and the Mount Pleasantmine, Charlotte britannique, 2) d la mine lkuno, pr6fecture de Hyogo, au
County, New Brunswick. The mineral is orthorhombic wit!
Japon, et 3) d la mine de Mount Pleasant,comtede CharspacegroupPmr.t2vZ:2, a7.667\ b 6.4399,c 6.2605A
lotte, au Nouveau-Brunswick.C'est un min€ral orthorhom(Herb);a 7.7050,b6.9462,c 6.2757A (Ikuno) and a 7.6858, bique, grgupe spatid Pmn2y Z = 2, a 7.6671,^b6.4399,
b 6.4395,c 6.294.7A (Mount Pleasant).Microhardness c 6.2@5ix(Herb),a7.7050,b 6.4462,c 6.2757A (Ikuno),(VHNM) is 319. Results of an electron-microprobe et a 7.6858,b 6.4395,c 6.2947A (Mount Pleasant).La
analysis gave the average formula (Cu1.65Fe9.952n6.gmicroduret6(VHNI6g) est de 319. La compositionchimiAg6.e3)s3.67(Sno.rglao.os)ro.sas3.ee
for Herb claim specique moyenne, d'aprbs une analyse d la microsonde 6lecmens, corresponding to the general formula
tronique, serait (Cu1.ssFes.s5Zns.2aAgo.ot)rr.oz(Sno.ss(Cu,Fe,Zn,Ag)3(Sn,In)Sa
where Cu >Fe > Zn >>Ag and Ino.os)ro.saS:.eepour l'dchantillon de l'indice de Herb, ce
g6n6rale
Sn > In. The composition is somewhatvariable and can be qui
formuledlacorrespondaccountd for by a coupled substitution Cu + Sni In + Zn.
(Cu,Fe,Zn*A.g)3(Sn,In)Sa,
danslaquelleCu >Fe>Zn >>Ag
Indium substitution appears essentialfor the stability ofet Sn> In. La composition varie l6gbrementselonle couple
the mineral, causing a distortion in a ferrokesterite-likede substitutron Cu + Sn =ln + Zn. La prdsencede
atomic arrangement and resulting in limited disorder l'indium serait essentiellepour assurer la stabilit6 de la
betweenCu and @e,Zn). The strongestreflectionsin the petrukite, en causant une distorsion de I'agencement
X-ray powder pattern are: 3.13(10X002),1.915(6)(400), atomique du modble de la ferrokesterite et un faible
1.I 06(0(3I s), 1.243(5Xl5l) and 2.7r2(4)(r2l) for the Herb d€sordreimpliquant Cu et (Fe,Zn). Les cinq raies Ies plus
claim specimen.Holotype isostannite, as well as topotype
intensesdu clichdde diffraction (m6thodedespoudres)sont
occurrencqs,were investigated and found to be identicall. 106(6x3I 5), 1.243(5)(15l)3.l 3(10X002),1.915(6X400),
to a member of a kesterite-ferrokesteritesolid-solution
et2.712(4)(l2l) pour l'Echantillonqui provient de I'indiceseries. Thus, no cubic polymorph of stannite exists, de Herb. L'isostannite hololypique, de m6meque la 6chanalthough its as yet unsubstantiated existence is nottillons topotypiques, ont 6t€ examin6set trouv6s identiques
precluded.
i un membre de la solution solide entre kesterite et ferrokesterite. Il est donc clair que I'existence du polymorphe
petrukite,
Keywords: new minerals,
ferrokesterile, isostancubique de la stanniten'est pas 6tablie, quoiqu'elle n'est
nite, kesterite, Cornwall, New Brunswick, British
pas exclue.
Colurnbia, Japan.
(Traduit par la R6daction)
SOMMAIRE
Nous avons d€couvert deux esptcesmin€rales nouvellesmin€rales,petrukite, ferrokesMots<lds: nouvellesesp&ces
terite, isostannite, kesterite, Cornouaille' NouveauBrunswick, Colombie-britannique,Japon.

673

674

THE CANADIAN MINERALOCISTINTRODUCTIoN

163779),The mineral is named in honor of William
Petruk (b.1930),Canadianminslalpgisf,who noted
the possibleexistenceof petrukite in h\ study of theMount Pleasantores (Petruk 1973).

In a previouspaper, Kissin & Owens(1979)attempted to summarizethe status of tin-bearing sulfide minerals in the systemCu-Fe-Zn-Sn-S. At thattime, only one mineral of stannite composition
MsrHoDs oF STUDY
was discussed,as we alreadysus[Cu2@e,Zn)SnSo]
pected that isostannite, the purported cubic polySpecimensdescribedin this study were analyzed
morph of stannite, is in fact identical to kesterite on a Materials Analysis Company MAC) model400(Kissin& Owens1975).Continuing work on miner- electron-microbeam analyzer operated at 20 or 25
als of this systemhasnot only confirmed the identity kV and 0.03 pA specimencurrent. The compositionsof isostanniteas kesteriteor ferrokesterite,but has and homogeneity of the specimenswere determineduncovered two new minerals of stannite-like from data acquired by collecting counts for l0-s
periods from 5 to l0 spots on a grain. Concentracomposition but differing in structure.
The new mrneralferrokeskrtte [Cu2@e,Zn)SnSo] tions of the major componentsCu, Fe, Sn and S wereis the iron analog of kesterite;although of tetragonal measuredby meansof the CuKcu,FerKcr,SnZa andsymmetry like stannite, it differs in having the space S,l(n lines, calibrated against synthetic Cu2FeSnSo,group.I4 of kesterite.Ferrokesteriteapproachesthe and for Zn using the ZnKa line of syntheticiron end-memberof a kesterite-ferrokesterite solid- Cu2ZnSnSa.Synthesis and description of the synsolution seriesand is a polymorph of stannite. The thetic standards have been given in our previous
mineral occursin the Cligga mine, Perranzabuloe, papers. Minor Ag, Cd and Mn were determined
Cornwall, England. The material is preservedas no. using Agl,cu, CdZo and MnK<r of pure metal stan14147of the National ReferenceCollection of the dards. Indium was determined using InZcr and synGeological Survey of Canada, which acquired it as thetic InAs. The data were reduced using thea small hand specimenlabeled"isostannite" through EMPADR VII program of Rucklidge& Gasparrini
purchaseof the Barstow Collection. Two polished (re6e).
sectionslabeledA and B and a polishedgrain mount
X-ray powder data were obtained by meansof asection were made from material cut from the hand 114.6-mm Gandolfi camera, as its small sample
specimen.Polished sectionA and the grain mount capacity provided the best means of obtaining
are designatedas cotypes and have been deposited impurity-free patterns,aithough we werenot successwith the GeologicalSurveyof Canada,Ottawa (no. ful in obtaining patterns free of impurities^in all
65048) and the British Museum (Narural History),cases.Filtered CoKa radiation O: l.79O2l A) was
London (no. BM 1984, 8M), respectively. The employed;d valueswprealsocalculatedfor resolvgd
polished section B and the hand specimen are CoKcl O= 1.73890A; and CoKa2O= 1.79273A)
designatedmetatypesand also were deposited withreflections. Relative intensities were estimatedthe GeologicalSurvey of Canada.
visually. Cell parameterswere obtained by meansof
The new mineralpetrukitehasa compositionvery the PARAM least-squaresrefinement program ofsimilar to that of stannite,but slight nonstoichiom- Stewart et al. (1972). Single-crystal studies wereetry involving the Cu and (Fe,Zn) sitesis present. carried out using a precessioncameraand W radiaA small but perhapsessentialamount of In is present tion. Reflectanceswere measuredin air using aI*itz
in the Sn site as well. The symmetry of the crystal MPE microscopephotometer with either a silicon
structure, however, is decreasedto orthorhombic
referencestandard (N2538.42,issuedby the IMA
Pmn2y The mineral was discoveredin three localicommissionon Ore Microscopy)or a siliconcarbide
ties: l) the Herb claim, on Turnagain River, Cassiar standard(Zeiss474251).Microhardnesswas deterDistrict, British Columbia; 2) the Mount Pleasanr mined on a Leitz Durimet hardnesstester using amine, CharlotteCounty, New Brunswick,and 3) the 100-9load for a l5-s duration.
Kanagasevein, Ikuno mine, Hyogo Prefecture,
Japan. Cotypes in polished section from all three
ISOSTANNITE DISCREDITED
localities have beendepositedin the National ReferenceCollectionof the GeologicalSurveyof Canada
Isostannitewas describedin an abstractonly by(nos. 65049,65050,65051and 65052,respectively). Claringbull& Hey (1955);it occursin materialfrom
Metatype specimensin polished section from the Cligga Head, Perranporth, Cornwall, England. No
Herb claim have been deposited in the American data were given, but the mineral was describedas
Museum of Natural History (AMNH T98797), Brithaving the composition of normal stannite, but with
ish Museum(Natural History) (BM 1987,94),Mus6e a cubic structure. The holotype is depositedin thede Min6ralogie, Ecole Nationale Sup6rieuredes BritishMuseum(NaturalHistory), no. BM 1955,317.
Mines, Paris (T44352)and the National Museumof Other localities containing isostannitewere indicatedNatural History, SmithsonianInstitution (NMNH
by Claringbull & Hey: Zinnwald, Bohemia, Czecho-

675

THE RELATIVES OF STANNITE

slovakia; Via Carmen, Tatasi, Bolivia and Snowfl,ake
mine, Revelstoke,British Columbia. The specimens
they mentionedwerenot identified, and we havehad
no successin locating them.
A polishedsectioncontainingholotype isostannite,
as well as one identified as "isostannite" from the
Cligga mine, Perranzabuloe, Cornwall, England,
were studied. Topotype material from Zinnwald
identified as "stannite" (NMNH C5233) and fromthe Snowflake mine identified as "zincian stannit€"(UT 218)also were studied. The latter is the material
collectedby Qsnning (1929)and describedby Berry& Thompson (1962).A specimenfrom Vita Carmen,
Tatasi, Bolivia, could not be located.
The polished section of the holotype consists
largely of massive,but polycrystalline, grains ofstannfte-goup minerals that display complex interrelationships, together with minor quartz and small
inclusions of chalcopyrite at an arrested stage ofalteration to covellite and sphalerite. The chalcopyrite and sphalerite inclusions vary from millimetersto submicrometersin sizeand in many areas
are very abundant in the stannite-group minerals.
Optical examinationsmade with the aid of a l:1
HNO3 etch (Hanis & Owens 1972) indicate thepresence of very complex textures varying fromstannite to stannite with exsolved lamellae ofkesterite,to kesteritewith exsolVedlamellae of stannite, to kesterite.Later generationsof inclusion-freestannite and kesteritewere depositedin very narrow
bands along cracks in the original material.
The more inclusion-free areasof the kesterite display very weak reflection pleochroismfrom medium
grey to medium grey with a brownish tinge.
Anisotropy is weak but distinct in shadesof grey.
The optical properties were determined under oil
immersion because of the enhanced reflection
pleochroismand anisotropy.
Table I presentssom.positionsof specimensrelated
to the isostannitequestion. Composition I is theunpublished result of a microchemical analysis ofholotype isostannitemadeby M.H. Hey. Compositions 2 and 3 are tle resultsof microprobe analyses
of inclusion-freeareasof kesteriteand stannitefrom
the holotype specimen. Analysis 4 pertains to amineral resemblingkesteritebut with more iron tlan
zinc. As shown later, this mineral is ferrokesterite,a new species.The locality is the same as for theholotype isostannite; the Cligga mine is located at
Cligga Head, and Perranporth is a town in the parish of Perranzabuloe(C.J. Stanley, pers. comm.
1985). Analysis 5 pertains to mas$ive kesterite,
whereas 6 and 7 describe exsolution lamellae ofkesterite in stannite, respectively.
The weakly anisotropic material of kesterite composition was extracted from the polished section ofholotype isostannite. The powder pattern is compared with that of topotype kesteritein Table 2. The

'I.
rAELE

ut.
C\
Ag
lln
zn
cd
sn
Ins
total

IIATERIAISOF ISOSTANNIIEAIIDRELATED
COilMSITIONS

29.2

29.5

4.1

ll.3

2.21

l0.,

l.,

28.54

26.7
0.M
29,7
'100.5

27.9
0.03
29.9
100.4

29.72

29.s8
99.40

8.2
0.1
5.2
-

29.6
99.8

6.5
o,o2
7.8
0.17
26.5
0.07
29.9
t01.0

2.00

2.03

0.64
0.01
0.35

0.50

27.5
-

29,0
o.42
4.4
n.d.*

29.3
0.ll
4.2
n.d.

0.10
0.28
27.1
27.0
0.13
0.12
29.2
29.5
99.9
100.r

atonlc prcportlons (8 atm)
Cu
Ag
Fe
llrl
zn
Sn
lns

2,04
0.73

o.r,

o.r,

0,15

0.72

0.12

I.05

olr, ,.0,

'I
.01

4.03

4.01

4.00

o.ut
0.01
:''g6

4.01

4.00

2.00
0.02
0.35

2.00

0.64
-

0.36
0.01

0.01
3.99

3.99

0.64

. Dashdenotssnot deteminedi * n.d. denotesnot deteted,'1.
holotype lsostunlte
Perruporth, Cormall, England. B.lit.1955,317;Hey (p€rs. com.).
2. holotypelsostannlte (kesterlt€)
Pefreporth, Cornyall, England. B.u. 1955'317ithis mrk.
3. holotyre lsostannlte {stannlt€)
Perruporth, Cofmall, England. B.ll.'1955'317;this mrk.
4. olsostmnlte' (ferrckesterlte)
Penmzabulm, cormall, England. o.s.c. 14747;tils mrk.
5. lstilnite" (kesterlte)
c5233, gr. li Klssln &zlnmld, Bohdla, Cz€hoslovakia. NUNH
o*ns (1979).
6. 'zlnciu stannlte" (kesterlte)
Snorflakeolne, Brltish Col@bla. UT218; Klssln & ohrns (1979).
7. 'zlnclu stamlteo (stannlte)snouflakeEln€, Brltlsh Col@bla. uT 218; Kissln & orens (1979),
Note: In the above; orlglnal ldentlficatlon is ln quotatlon narks;
ldentlficatlon ecordlng to this rork ls in parentheses. B.l,l.: Brit.
l'tusee (Iatural History); C.S.C.: Natlonal ReferenceCollction,
Natlonal lluse@of Natural Hlstory'
Gsloglcal Surveyof Cmadai l{l.lLlH:
Solthsonlu lnstltutloni UT! Departnentof Cslogjf coll*tlon.

pattern cannot be indexed on a sphalerite-like cubic
cell; howevel it is strongly pseudocubic,with a =10.8629(18)A. As reflectionsindicating tetragonal
symmetrywerenot resolved,cis presumedequalto
2a within the limitations of the method.
The powder patterns of holotype isostannite andkesterite are clearly those of the same mineral. All
reflections in isostanniteare indexableon a kesterite
cell exceptfor a very weak one at d:2.12 4,, which
is attributed to an unknown impurity. ZeroJevel
precessionphotographsof holotype isostannitewere
compared with those of kesterite from Oruro,
Bolivia. The latter specimenwas used in a structurerefinement (H:all et ol. 1978).The photographs are
identical and reveal a Laue symmetry of 4 and thediffraction symbol I4/*, wrth permitted reflections
corresponding_1o h+k+/:2a.
Possible spaceCroupsare 14,14 and I4/m; the structure of kesterite
was refined in f4 GfaU et al. 1918).
On the basis of the foregoing evidence,it is clearthat all minerals of low anisotropy in holotype or
topotype isostannitecorrespondto kesteriteor, inthe caseof analysis 4 (Table l), to the new mineral

676
TABTE2.

THE CANADIAN MINERALOGISTX.RAYPOIDERDATAFORISOSTAIIilITE
COMPAREDTO }IOSE OF
KESTERIIE
hololype lsostannlte'

topotype kesterite'nkl

d(obs) d(calc) I/Id(obs)d(calc). I/l002
0'| 1 1l2
013
020,004
022
t2l
il4

5.4r
4.85
3.13
3.O2
2.72
2.43
2.37
2.22
2,12
2.01
1.920
't.638

3 .t 4

3.14

2.72

2.71

2

2.37

2.37

<I

2,02 2.O2
1.922 1 0 l o
1.638

<l
'10

1.567

<l
<l

123,015zzo,o24'132,1
l6
224

5.43
4.85
3.14
3.01
2.12
2.43
2.37
2.22

?.oz
1.920
1.638
1.565 I .568

I

2
l0

I

t/2
8

,:-- , :-^0€,008'l4t

t. J90t.Jro

t.i.qs r.ica

JJZ, tJO

90M,028,240
t' 1. ?. 11037 1 . 2 t 5
244,224
l.109
3
4
1
,
0
5
1
1
,
2
9
'152,336,
l.l.l0r.iqq r.oar
251,039055,345
440,048o.ior o.ioo
352,156,t.3.10
0.918 0.918
248,444,060,0.0.
t2
062
260,064
3 5 6 , 3 . 3t.0

I.JYU

1.357
1.308
1,246
1.2r3
l.107
1.081
1.044
1.004
0.970
0.960
0.9't8
0.905
0.891
0.859
0.828

't.307
1.245
1.214
1. 1 0 8
1.080
t.045
1.004
0.971
0.960
0.9t7
0.904
0.892
0.858
0.828

<l
<l

round inclusions of sphalerite and chalcopyrite.
Some areas of stannite with copious exsolutionlamellae of kesterite occur in grains surrounded byarsenopyrite (Fig. 2A). Thesegrains differ considerably in compositionfrom most of the ferrokesterite
and were evidently chemically insulated by theenclosing arsenopyrite. Elsewhere,in the same
polished section, lamellae of kesteriteform a latticelike array within a stannite host (Fig. 2B). The textute closelyresemblesthat illustrated by Ramdohr(1960,Fie. 398)and attributd to lamellaeof isostannite in a host of stannite.The compositionsof these
intelgrowths are given below in Table 4 (analyses4
and 5; 6 and 7, respectively).
Petrukite

<l
<l
<l
I
<l
<l

d-values exlressed 1n A.
1 Thlsrork a 5.4315,c 10.8629EiII4.6u! Gandolfl md coKs.
2 lvanoy & piatenr<o(tlsg)
a 5.43, c ro.e6f, t:c.6^ Debye-scherrer
and coKq,

ferrokesterite. The discreditation of isosrannite (:a member of a kesterite-ferrokesteritesolid-solution
series)was approved by the IMA Commissionon
New Mineral Names.The equivalenceto kesteriteor ferrokesterite(or both) was specifiedbecauseof
the probable presenceof both mineralsin the type
locality.
OccunnrNcs or FtsnnorssrERlTE
AND PETRUKITE

Ferrokesterite
The mineral occursin sulfide-bearingveinsof tin
ore from the 60-m level, Cligga mine, Perranzabuloe, Cornwall, England. The veinsoccur in the Cligga
granite, a small pluton of Permo-Carboniferous age
on the north coastof Cornwall (Hosking 1969).The
veins in the granite have been classified as greisenborderedveins by Hosking (1969),who also gaveasummaryof t}te tin depositsof Cornwall. 11p Qligga
ores were recently describedby Moore & Howie(1984),who presentedresultsof analysesof material
they called zincian stannite, which evidently isferrokesterite.
The hand specimeninvestigatedby us consistsof
massive ferrokesterite in association witharsenopyriteand quartz, aswell asminor cassiterite,
chalcopyriteand sphalerite.Cracksand crain boundariesare rimmed by late (supergene?)chalcocite(Fig.
1). Most areas of ferrokesterite contain minute,

The Herb claim, the ffust of the three localities,
occursat 58o41'N, l28ol0'W, about 8 km nofihwest of the confluence of the Turnagain and Cassiar Rivers, British Columbia. The claim is describedas consisting of galena-and sphalerite-bearingveinsin highly kaolinized eranite (B.C. Dep. Mines &Petroleum Resources1970). The veins occur inassociationwith rhyolite and rhyolite porphyry sills
and dykesthat intrude a granitic stock, an offshootof the Cassiar plutons (R.G. MacArthur, pers.
comm. 1983).Petrukite in the Herb claim occursas
small, round grains (up to 2/0 gm in diameter)within
massivegalenaor sphalerite(Figs. 3A, B). The grainsare either inclusion-free or occasionally occur asrhythmically alternating concentric growths withsphaleritewhere enclosedin quartz (Figs. 3C, D).
Within the samehand specimens,in order of decreasing abundance,are galena, potosiite (c/. Kissin &Owens 1986a), quartz, pyrite, sphalerite andarsenopyrite.
The geology of the Ikuno mine, a xenothermal,
polymetallic vein-type deposit, has been describedby Imai et al. (1978).Petrukite occurs at the type
locality for sakuraiite (Kato 1965),in the Senjuhonhi
vein ofthe Kanagasegroup of veins,in only one ofsevensymmetricallybandedzonesof the vein. Details
on the occurrenceof sakuraiite were recently given
by Shimizu et ql. (1986). Based on the characteristics given, the mineral designated as stannite
evidently is petrukite. Petrukite occurs rna2.54-cmdiameterpolishedsectioncontainingthe 2-cm-wide
sakuraiite- and petrukite-bearing zone. One edgeof
the zone consistsof massivesphaleritethat showseuhedral terminations into rhythmically banded
sakuraiite,petrukite and sphaleritd(Fig. 4).Each ofthesebandsis a few hundredsofpm thick. Growthzones in sphalerite are outlined by trains of
micrometer-sizedchalcopyrite grains. Chalcopyrite
also occurs as micrometer-sizedisseminationsinsakuraiite and petrukite and as wormy stringersthat
crossthe growth zonesof the section.Irregular areasof gangue and small cassiterite grains, as well as677

TIIE RELATIVES OF STANNITE

small, euhedral arsenopyrite crystals, also occur inthe section.
The geology of the Mount Pleasantmine has been
describedrecentlyby Kooiman el al. (198A. According to their interpretation, the deposit consistsof atungsten-molybdenum porphyry-style orebody
associatedwith an earlier fine-grained granite andpolymetallic vein-type ores associatedwith a later
porphyritic granite phase of an altered Devonian
stock. The mineralogy of the entire deposit has beencataloguedby Panish (1977);the mineralogy of tinbearing sulfides associatedwith the lead, zinc, copper and tin sulfides in the vein system has been
describedby Petruk (1973), who first noted theunusual characteristicsof the stannite-like material.
According to Kooiman et al. (1986), Petruk's
sampleswere taken from what is presently known(etchedas the Fire Tower North orebody, no. 7 lode. Frc. l. Ferrokesteriteby arsenopyrite
surrounded
Petrukite occurs in two polished sectionsused inchalcocitelines
with l:1 HNo3). Late (secondary?)
traceincracksin the ferrokesterite.Notetlle cleavage
Petruk'sstudy,nos. MP90.901.5and MP92.901.5.
theupperleft (reflectedlight). (CSC65048,sectionA).
In thesesections,petrukite occursas inegular, roundgrains of various sizescontained in quartz. Somegrains are rimmed with chalcopyrite, and many conism is faintly visible in shadesof lighter to darker
tain micrometer-sized inclusions of chalcopyrite.
grey.Anisotropy is weak in shadesof grey. Bireflectanceis weak but measurable;dalaare presentedin
PrrysIcaI PRoPERTIES
Table 3.
Ferrokesterite

Petrukite

In hand specimen,ferrokesterite is steelgrey witha metallic luster. The mineral has a Mohs hardnessof about 4 and yields a black streak. Although nofeatures of crystal morphology are visible, cleavage
parallel to {110} is distinct, and parting develops
parallelto {001}. Microhardnessis givenin Table 3.
Petrukite
Macroscopicpropertiesof color, streak and luster
werenot observableowing to the small grain-sizeof
the material. Grain diameter is a maximum of 240
pm in the Herb claim specimensand 300 to 400 pm
in the Mount Pleasant material. Laterally continuous bands that are only about 200 pm thick occur
in the Ikuno mine specimen.Crystal forms were notobserved; habits are round and anhedral. Distinct
parallelto {110}, {100} and {010} werecleavages
observed,aswell aspartingparallelto {001}. Polishing hardnessis greater than that of galena and lessthan that of sphalerite. Microhardness is given irl
Table 3 for the Ikuno mine specimen.
OPTICAL PROPERTIES

Ferrokesterite
In reflected light (air path), ferrokesterite is
medium grey and cannot be distinguished fromkesterite.Under oil immersion,reflectionpleochro-

Color in reflected light with air path and oil
immersionvaries somewhatamong the specimens,
apparentlyas a function of zinc content. The Herb
claim material, with the lowest zinc content, is distinctly brown (air) or greenishbrown (oil), but lacks
the strong reflection-pleochroismof stannite.Very
faint reflection-pleochroismis visible under oil
immersion,in shadesof greenishbrown. The color
is increasingly grey with increasing zinc content in
the Ikuno mine and Mount Pleasantspecimens,andreflection pleochroismunder oil immersionis very
faint in shadesofgrey. In thesesections,petrukite
strongly resembles kesterite and ferrokesterite.
Bireflection is weak but measurable;data for the
Herb claim specimenare presentedin Table 3.
CttsMtsrnv
Ferrokesterite
The ferrokesterite in polished section A (GSC
65048)and grain mount (BM 1984, 844) contains
many micrometer-sizeinclusions; however, clear
areasin both specimenswerefound, and their compositionsare givenin Table 4 (anal. 1, 2 and 3). The
compositionsshowlittle variation in the proportionof zinc and iron (Zns.67FeM).This composition lieson the iron-rich side of the stannite-kesterite
pseudobinaryjoin and thus representsan extension

678

THE CANADIAN MINERALOGIST

significant variations in copper, zinc and indium
contents. The Mount Pleasantspecimensare poorer
in iron, zinc and indium than the Ikuno mine
specimens.
The analysesrevealtrends illustrated in the atomic
proportions column of Table 5. Whereasthe sum of
the proportions, based on eight atoms, yields
Cu+ Fe+ Zn=3 and Cd + Sn+ In= I and would beconsistent, from this standpoint, with the structural
formula Cu2@e,Zn)SnSo,
the proportion of Cu is
greater tharl.2, and that of Fe+Zn is lessthan l.
Thus, a general structural formula for petrukite is(Cu,Fe,ZnlSnSa. All analyses reveal a small but
significant contentof indium. Moreover, the deficit
in the proportion of copper appeaxsto be correlatedwith the proportion of indium.
Compositionsl1-15 show a further relationshipin that they may be ranked not only in order of
deoeasingcopper and tin and increasingindium contents, but increasing zinc content as well. Iron isnearly constant, which suggeststhat zinc plays animportant note in maintaining charge balance andstoichiometry.
-

CRYSTALLOGRAPHY

Ferrokesterite
Table 6 compares the X-ray powder-diffraction
data for ferrokesterite with those.of synthetic
Cu2(Fes.TZnM)SnS4synthesized at 800oC (Kissin1989). The agreementbetween the two patterns isgood for the observedreflectionsin ferrokesterite;
Ftc. 2. Back-scatteredelectronimagesof stannite-kesterite however,the pattern for ferrokesteriteis weakerthanintergrowth.A. Stannite(darker)containingoriented that of its synthetic analog, and only one reflection
lamellaeof kesterite(ighter). Thegrainis enclosed
in with l:2n + I is observed.The patternsare indexed(GSC65048,sectionB, area2), B. Stan- in the tetragonal systemand have permitted reflecarsenopyrite
nite (darker)with an arrayof kesteritelarnellae.(GSC tions obeying h + k + I : 2n.
65048,sectionB, areal).
The very small difference rn?n compared to c inkesterite leads to the superimposition of pairs ofreflections such as 020-0M and 136-332 in the Xof the kesteritesolid-solution toward an iron endray films, as drscussedby Kissin & Owens (1979).
memb€r (Frg. 5).
However, in ferrokesterite,1.3.10is resolvedfrom
the pair 156-352, whereasin the synthetic analog,
Petrukite
the reflections are superimposedin a single, broad
Compositional data for petrukite are presentedin reflection, apparently becauseof a slightly greater
Table 5. The data from the Herb claim (anal. 1) are difference in2a versusc than in kesterite. The only
given asthe meaaof eight analysesof various grains, surprising feature is the absenceof the strong rewith the corresponding ranges. With the exception flection for 132-l 16in ferrokesterite. The reflection
is present,however,in precessionX-ray photographsof silver, real compositional variations are insignificant. Analyses2-5 from areasof t}te Ikuno mine sec- and in other powder-camerafilms not included here
becauseof serious problems with reflections fromtion reveal some inhomogeneity with respectto the
distribution of zinc, tin, copper and indium. These other mineral inclusions.The absenceseemsto be
an aberration in this specimen.
areasare richer in zinc and indium and poorer in iron
Ferrokesterite can be seen to be an iron-richthan the Herb claim samples.Analyses6 through l0
wereobtainedfrom Petruk's (193) section90.901.5, memberof a solid solution involving the (Zn,Fe) site,
and analyses1l through 15, from section92.901.5. by comparison of cell parameters as a function of
All these compositions are similar, with minor but
composition of this site. Figure 5 illustrates such aTHE REI.ATIVES OF STANNITE

679

Frc. 3. Textural relationships of petrukite in the Herb claim occurrence (reflected lighO. A. Petrukite (medium grey)
rimming sphalerite (dark grey) in galena 0ielt gey) (oil immersion). B. Anhedral grain of petrukite (medium grey)
in galena 0ight grey) (oil immersion). C. Rhythmic intergrowths of sphalerite (medium grey) and petrukite 0ight
grey) in quartz (dark). D. Rhythmic intergrowths of sphalerite (medium grey) and petrukite 0ight grey), illustrating
two cycles of deposition within a matrix of quartz (dark).

plot, utilizing data from natural stanniteand kesterite
giveriby Kissin& Owens(1979).In stannite,2a andc are clearly distinguishable, whereasin kesterite 2aand c cannot be distinguishedin apowder-diffraction
pattern. In the latter case,indicesbasedon a 10.8
A unit. cell were usedin the calculationof d-values
for a pseudocubiccell, exceptfor sample7, whoseparameters were derived from the structure refinement of kesterite (tIaJl et al. 1978).Figure 5 showsthat the cell parametersof kesteriteremain essentiallyconstant vrith increasingiron content in the (Zn,Fe)
site, with no tendencyto the clear distinction between?a anidc, as shown by stannite. Contrary results
reportedby Corazzaet al. (1980 are discussedin Kissin (1989).Ferrokesteritelies near the trend of cellparametersver,rat composition for kesterite, but on
the Fe,Zn side of the diagram.
PrepessionX-ray photographs of the first threelevels of a single crystal reveal a Laue symmetry of
4/ m and the diffraction symbol 4/ mI-, with permitted reflectionscorresponditgto h + k + l: 2n. Possible space-groupsareI4/m, 14 andi4; however, inanalogy with kesterite, the correct space-group isbelievedto be A Gtall et al. lW8). Z, aswell, is taken

680

THE CANADIAN MINERALOGIST

Frc. 4. Photomicrograph (reflected light) of banded ore from the Ikuno mine.
Sphalerite (dark grey) shows euhedral terminations into rhythmicaly banded
petrukite (light grey) and sakuraiite (darker grey). Trains of chalcopyrite blebs(white) transect the zones, and an anhedral grain of cassiterite(black) occurs at
the right of the photograph (GSC 65052).

The patterns were indexed on the basis of an
orthorhombic unit-cell, with all general reflections
hkl permitted, and hOl only for h+l=2n, Thelave l ength
R.'
Rt.
Rz
%
pdtterns from the Herb claim and Mount Pleasant
470 @
23.9
26.8
27.0
27.0
546
26.0
27.0
27.8
27.7
specimenscontain several reflections from galena
26.3
27.3
?7.6
n.5
650
27.4
27.1
and sphalerite, respectively, which are not listed in
YHll1ee
Table 7. As well, the Heqbclaim specimenhasa weak
@ar
2W
3l9
rang€rreflection at d = 5.46 A, which is not indexablein
228-255
296-353
the proposed space-group. The X-ray patterns are
FlYe rotated lndentatlons
very similar to that of kesterite and can be distinguishedonly by the careful observation of a number
as2, asspecificgavify could not be accuratelydeter- of weak reflections. For comparison, the reflections
mined owing to the high content of inclusionsin most have been indexed on the basis of the tetragonal,
pseudocubiccell of kesteritein the riefit-hand column
areasof tle specimen.The calculateddensityis 4.490
parameters
a 5.433(36),c of Table 7. Asterisks indicate the corresponding
B cm-r, baryd on the cell
10.SS4(S9)A, obtained by a least-squaresrefinement reflections of the orthorhombic cell not permitted
by the space group of kesterite Ol4). These weakof the 12 reflections reported in Table 6.
No evidenceof twinning was observedin polished reflections provide the only meansof distinguishingpowder patterns of petrukite and kesterite.
section nor in the single-crystal X-ray photographs theThecell parametersderived from the least-squaresof ferrokesterite.However, preliminary resultsof astructural refinement indicate intensity distributions refinementsof the powder data are as follows: Her!
claim: o 7.6671(81),b 6.4399(32'),c 6.2605(61)A,
consistentwith the presenceof twinning.
basedon 25 reflections; IKuno mine: a 7.7050(27),b 6.M21(14),c 6.2757(?,5)
A basedon 26 reflections;Petrukite
Mount Pleasant:a 7.6858(101),b 6.4395(ffi),c
The X-ray powder-diffraction data for petrukite 6.2947Q3)A Uasedon27 reflections.Axial iaiios,
from the three localities are given in Table 7. calculated from these parameters, are: Herb claim

TABLE3. REFLECTIVITYAIIDI.IICROHARDNESSOFFERROKESTERIIEND PETRU(I]E
fenoksste.l te

petruklte

681

THE RELATIVES OF STANNITE
ANDKESTERITESTANNITE
ANDASSOCIAIEDDATAFORFERROKESTERITECOMPOSITIONALTABLE4.

l. 6raln 6ferrokesterlte
2. Sect. A, area I
ferrokesterlte
3. Sect. A, area 2
ferrokesterlte
4. Sect. B, area I
stannlte host
5. s€ct. B, area I
kesterite
I anelI ae
6. Sect. B, arca 2
stannlte host
7. Sect. B, area 2
kesterlte
I anelI ae

Cu

Fe

tn

29.5

8.7

5.0

29.'l

7.9

6.0

S

Total

Atomic Proportions I
Mn
Cd
7n
Fe

Cu

Cd

Sn

0.1

0.1

2 7 , 4 3 0 . 1 1 0 0 . 9 1 . 9 9 0.67

0.2

n.d.

27.3

0.33

0.00

0.99

4.02

?9.5

100.0 t.99

0.61

0.40

o.o2

1.00

3.99

29.6

99.8

0.64

0.35

0.01

1.01 4.00

2.00

0.00

29.2

a.?

5.2

0.I

n.d.

27,5

29.1

7.9

5.8

0.'l

n.d.

?7.4 30.r

1 0 0 . 4 1 . 9 7 0.61

0.38

0.01

0.99

4.04

28.9

4.6

9.5

0.1

n.d.

27.'l

29.9

1 0 0 . 1 1 . 9 7 0.36

0.63

0.01

0.99

4.04

29,1

8.2

5.J

0.2

n.d.

27.6

29.8

1 0 0 . 2 1 . 9 8 0.63

0.35

0.02

l.0l

4.0r

4.4

9.4

0.1

n.d.

77.6

29.9

1 0 0 . 2 1 . 9 7 0.34

0.62

0.01

r.0l

4.05

28.8

on.d.! denotesnot detected. Ag and in were sought but not detected ln all cases. Concentrationreported in l|t. f.

F}-1 Typicolerror limitsot lo-

o<
.E

6!

t0.90

(l)
(l)

6

I RLI---4

E

o
o
(L

c)

.9

FERROKESTERITE

a'

lO

12
z'rCI-C
9il

STANNITE

KESTERITE

r0.80

o
J

54

O IIOF--62
I
t0.70

0.500

Fe(*Mn)"1'OOO

Z n ( * C d) = l ' 0 0 0Contentsof the ( Fet Zn ) Site
Frc. 5. The dimensions2a versusc in stanniteand kesteriteas a function of composition,showingthe relationshi! of
ferrokesterite to the other two species,Cell parameterswere obtained from least-squaresrefinements o{ X-ray powder data. The parametersof keJterite and ferrokesterite were refined using indices of a pseudocubiccell. Solid symbols are syntheticend-memberssynthesizedat 800'c. Data from Kissin & owens (1979).

:l; andMount
1.225l.029:l:Ikuno mine | .D8:1.U27:1.
:l :1.023
Pleasant1.221
Precessionphotographs of the first three levelsofa Lauea single crystal from the Herb claim reveal
is
Pmn2t
however,
P2pm;
arrd
Fmmm,
Pmn21
ate
symmetry of mm'm and itre diffraction symbol

682

THE CANADIAN MINERALOCISTTABLE5.

Cu
Ag Fe
l . H e r b c l a ' l n , n p a n2 7 . 4 0 . 9 1 2 . 4 3 . 5
0.4- 12.0- 3.1' -"r'"""^^27.3
28.0 1.2 12.9 4.5
z . I k u n ol d n e
26.7 9.3 7.6
area I
3 . I k u n om i n e
25.2 9.3 9.2
area 24 . I k u n om i n e
25.9
9.7 7.9
area 3
S.Ikunomlne
27,8
9.6 6.2
area 4
Pleasant 28.6 n.d. 8.2 5.6
6.1'lount90.901.5,9r.1
7.l'lountPleasant 28.0 n.d. 8.2 7.9. 90.901.5gr.2
8.!{ountPleasant 27.9 n.d. a.2 7.3
90.90l.5,gr.l,area A
g.lbunt Pleassnt 28.4 n.d. 8.3 6.8
90.901.5,9r.2.areaA
lo.ti|ountPleasant 28.4 n.d. 8.3 7.5
90.901.5,area B
ll.ltlount Pleasant 28.3 n.d. 8.2 6.5
92.901.5,9r.1
l2.libunt Pleasant 27.2 n.d. 8.0 8.2
92.901.5,9r.2
l3.lt'lountPleasant 26.8 n.d. 8.1 8.4
92.901.5,9r.3
l 4 . M o u nPt leasant 26.8 n.d. 8.4 7.9
92.901.5,9r.4
l s . M o u nPt leasant 26.9 n.d. 8.5 8.7
92.901.5,9r.5

COMPOSTTIOMLDATAFORPE1RUKITE

Atomlc Proportlons
Total Cu As
Fe
7n
Cd Sn
In
n.d. 24.8 1.3 29.9 100.3 1.85 0.03 0.95 0.24 0.89 0.05 3.99
24.3- 0,9- 29.6Cu+Ag+Fe+2n.3.07
Sn+In.0.94
25.3 1.9 30.3
0.4 22.8 3.4 30.2 100.4 1.80 0.71 0.50 0.02 0.8? 0.13 4.03
Cu+Fe+Zn=3.01
Cd+Sn+In=0.97
0.3 20.5 5.8 29.9 100.2 l.7l
0.71 0.61 0.0] 0.74 0.21 4.01
Cu+Fe+Zn=3.03
Cd+Sn+In.0.96
0.3 22.9 3.4 30.0 t00.t 1.75 0.74 0.52 0.01 0.9:, 0.13 4.02
Cu+Fe+2n.3.01
Cd+5n+In=0.97
0.3 25.0 1.9 29.9 100.7 I.87 0.74 0.40 0.01 0.90 0.07 3.99
Cu+Fe+Zn=3.01
Cd+Sn+In.0.98
0.2 25.8 0.6 29.8
99.8 t.94 0.63 0.rt4 0.01 0.94 0.02 4.02
Cu+Fe+Zn-3.01
Cd+Sn+In-0.97
0.2 25.1 0.8 29.9 100.1 1.89 0.63 0.52 0.01 0.91 0.03 4.01
Cu+Fe+2n.3.04
Cd+Sn+In-0.95
0.2 25.5 1.2 29.7 100.0 1.90 0.64 0.48 0.01 0.93 0.03 4.00
Cu+fe+2n.3.02
Cd+Sn+Ina0.97
0.1 25.4 1.2 zg,s99.7 1.94 0.65, 0.45 o.0o 0.93 0.04 3.99
Cu+Fe+2n.3.04
Cd+Sn+In.0.92
0.2 2s.8 0.7 29.6 100.5 l.9z 0.64 0.49 0.ol 0.93 0.03 3.97
Cu+Fe+2n.3.05
Cd+Sn+In=0.92
0.2 z6.s 0.7 29.3
99.7 1.94 0.64 0.44 0.01 0.97 0.03 3.90
Cu+Fe+Zn-3.02
Cd+Sn+in=1.01
0.2 25.9 0.8 zg.s
99.8 l.06 0.62 0.54 0.00 0.95 0.03 4.fl)Cu+Fe+2n.3.02
Cd+Sn+In.0.98
0.2 24-8 l.l
29.6
99.0 t.g4 0.63 0,56 0.01 0.91 0.04 4.01
Cu+FerZn=3.03
Cd+Sn+In-0.96
0.3 z4.g I.0 z9.g
99.0 l.g3 0.60 0.53 0.01 0.91 0.04 4.04
Cu+Fe+2n.3.02
Cd+Sn+In.0.96
0.2 24.5 l.l
30.4 100.3 l.8l
0.65 0.57 0.01 0.88 0.04 4.04
Cu+Fe+2n.3.03
Cd+Sn+In'0.93

on.d.o denotesnot'detected. A-.dashdenotes
not sought. li|nuas sought but not detected in the l4ountpleasant sanples.
Concentrationsreported in w!. %.

TABLE6.

X-RAYPOI{DER-DIFFRAfiION
DATAFORFERROrcSTEUTE

believedto be the correctone, basedon the analogy
with the enargitestructure (Adiwidjaja & L6hn 1970)
spthetlc ferrokesterttez
and other synthetic compounds describedby Parthdhkfd(obs)d(calc)tlthd(obs)d(calc)t/t,^
et ol. {1969). By analogy with rhe relarionship
3.13
3.14
lo
3.13
3.13
l1?
l' o
i
between the sphalerite and wurtzite structures, theur
0 rI 33.01
i . .o0i 13
1020,004 2.7't2 2.717
32.709 z.iit
relationship between the structure of stannite andi022
2.415 2.425
ipetrukite has been called the stannite - wurtzstan2.36e 2.371
1t2
2.365 2.s66
l?!
i
_
n4
2.20s ,.,1iinite relationship (Schiifer & Nitsche 1977).
2.006!?1,9!9
,.oii
i
1.e22
6
l.eia
??g,g?4 l.ele
i.tjt
iTwinning was not observedin polished section;
1.$,
192,!16i.4,6
6-_0.3J ,3, .,o1 2 5u1
r . .O5I g1 8
r1.. ;6i1i 7
however,
twinning was observed on precession
Ir?
1.566 r.so6,^?2t-- 1.555 1.569
iphotographsof many grains from the Ikuno mine
1.38e r:ass?!9'935i
0/m,008 t.363:--t.358t:
section (Frg. 6). In the 0kl* level, the operation of
1.?42 r.247
3
1.244 1.244
99,!!q5240.044.
'
the twin law is evident in the presenceof individual
1,212 1.212
l
oi}!
l.loe
crystalsI, II and III. The wurtzite-likeC axis coin4
1.106 .t.r07?y,??g l.lto
6051,341.
1.078 1.079
I
237.129rcideswith the C axis of individual .I, and the wurtzite.t.04?
r.045
like c* axis coincides with the D* axis of individual
3
r.043
r.044
5
l;l:i!rt.L Figure 7 illustrates in detail the formation of theii3:ff
3:3!3ia:ei,t
3:3f31ii ]0.e168!':Y 0.e165
e.:* 4878
r56,3s2 o.giei
twin cell with^symmetryR3m and dimensionsa 3.827
and c 9.365A, yery similar to thoseof wurtzite-3R' cSC
14747,gratn 6b a 5.433(36),c lo.B84(99)ff.
(a 3.82, c 9.42 A). As the orthorhombic symmetry' CUZ(FeO.7ZnO.3)SnS4
a 5.4220), c l0,g{r40)ff.
Pmn2, is a subgroup of the twin symmetry R3r1x,
the twin operates so as to produce the higher
symmetry. The discovery of this twin law is striking
mmmPn-. All generalreflections ,k/ are permitted, confirmation of the correctnessof the spac€groupas well as iOl with h + l:2n. possiblespace-groups determined for pdtrukite on the basis of X-rayare Pmmn, Pmn2, and F2rnm; howeverpmn2, is diffraction studies.
fermkesteri te I

683

THE RELATIVES OF STANNITEDATAFORPETRUKITE
X-RAYPOWDER-DiFFRACTIONTABLE7.

lkuno minez l'lountPleasantmineJ
Herb clainr
orthorhornblc
hkl
d ( o b s )d ( c a l c ) I / I l 0 d ( o b s ) d ( c a l c ) I / I r o d ( o b s ) d ( c a l c ) I / I l 0010

6.13 6.M

415
640
360
444

s-'l
0.98820.9896

-*

llz

-5.46-l101
I
lil
3.86 3.87
I
210
3.33 3.29020
l0002 3.13 3.13
4121
2.712 2.682
ll2
2
?02
2.421 2.4?5
301
'l
3ll
2.2l4 2,221
320
400
1.915 1.9'17 5
1.814 1.794 I
231
023
123 1.710 1.707 2
402 1.635 1.635 5421
1.568 1.565 1004
501
1.450 1.444
t
241
124
3lt0r
*-38
521'
242
1.325 1.321 2
224"t.243 1,245
5l5l
1.210 1.212 2
404
't52
1
1 4810 1 . 1 7 7 I' f .. 1
l.l4l
2
343
1.106 1.r08
6
315
630
542
1.0471.M7"v2
1.044 r.043
006
3

4.8I
3.90
-

4,87
3.88

3.12 3.14
2,709 2 . 8 7

r
]
l0
3

2.440 2-4?3 1/2
2 . 3 7 6 ?.377 I
2.207 2.230 1/2
2.005 2.009 l/2
I .917-r.e26
i1.636 1.642 5
1.s94 1 . 5 9 9 1 t 2
1 . 5 6 6 1 . 5 6 9 't/2
3
1 . 4 9 4 1.497
1.445 1 . M 7 1 / 2
1.363 1.365 3
1.343 t.3M ll2

'
I
_ilo

002
0ll

-a

3.17 3.22
3.11 3.'15
2.698 2.688
2.629 2.654
2.426 2.435
2.361 2.373
2.008 2.005
1.913 1.921
1.761 I.758
1.632 1.640

I
l0
3
1/2
'l/2
2
I
7
I
5

*
r12
020,004
*
022
121
ll4
123
220,024222*
130
132,116-i

1
11.391 1.391 112
2
I .359 1.363

1.568 1.574
1.497 I.493

1.245 1.246 4
1.217 1.217 t

1.24't 1.245
1 . 2 1 4 1. 2 1 7

4I

1.109 l.lll
51.102 1.102?

1.108 l.ll3
1.104 1.100

5I

l.0rt8 1.046 4
1.037 1.038 I

1.045 1.049
I .039 1.039

4
I

224
017,231134035
040.008
226,M?
332,136,'044,0282N
o37,ol9l.oo3 r.oo2

1

0 . 9 7 1 40 . 9 7 1 0 Ian) {9'9999'0.95879'999-4?
0.9584 I

0.e63tzo.gose316

0.95780.9579 3

o7o o.e2or
o.ezor, ,3.3!33
I
3:3i33235

4.78 4.87

I-

tetragonal
Jndexing
hkl

0.96290.9607
0.95790.9600

22. 0 . 9 1 4 00 . 9 I 5 4 2
r 0 . 9 1 4 20 . 9 1 5 4 I

244.2?8'.' 1
1.512.,1303 6
039,251
I,' 005. 1
5 ,. 215 3
048,440at56', 1 . 3 .I 0 , 2 5 3'I. 2 . 11 , 2 5 5

t Reflectlons at this d-value not pemitted in spacegroup of kesterite.
H Petruklte relectlons present but not measureddue to lnterference by galena.
B : b r o a d . d - v a l u e se r p r e s s e di n A . l a 7 . 6 7 7 1 ( 8 1 ) b, 6 . 4 3 9 9 ( 3 2 ) c, 6 . 2 6 0 5 ( 6 1 ) i ;2a7.7050(27), b
5.4462(14), g6.275766fAt 3a Z.Ogd(tOr), b 6.4395(60),c 6.2sa7(2s)A.

dividing bv
The twin law in petrukite is analogous (although ha.s&:fr :& = 55.?n49:.41.1316:38.1924;
not identical) to the twinning in enargitereported by a factor of eightyields6.W:5.2165:4.77405. Thus,
Pauling & Weinbaum (1934).Using a settingin which d:8 approaches7:S,and twinning is possibleinthe
a and b are reversedwith respectto the setting for zone{hlc0\. The Ikuno mine petrukite specimenhas
dividing bv a
petrukite, they determined the triperiodic twin with d:Fz& :' 59.3670:4L5007:39.38't4;
In thistwin plane (320), equivalent to (230) in petrukite. factor of eiebt yields 7.42O9:5.1876:4.9231.
possibleistwinning
and
5:5,
approaches
F:E
case
a
necessary
systemHowever, in the orthorhombic(031)
condition for twinning is that d:P:C approach in the zonelbfr[, in accordwith the twin law
that
noted
be
furtherItshouldinobserved
of
the
only
two
of
ietrukite.
rational numbers.If the squares
possiblecell dimensionsapproachrational numbers,twinning considerablevariation in cell dimensionsis
inis restrictedto the zonecontaining theseaxes@riedel in enargite (c/. Adiwidjaja & Ldhn 1970) andL92A. The Pauling & Weinbaum enargite specimen petrukite, and the presenceof twinning in either

684

THE CANADIAN MINERALOCIST

bt
\

cf=ct

t/

\

o?=
oi

+

n*F
VIIf

/

btr
Ftc.,6. X-ray precessionphotograph (MoJ(c) of the (0/r/)* level of petrukite fromthe Ikuno mine, illustrating the triperiodic twin it contains. The twin plane is (031).
, The twin law operatesso :rs.to produce a pseudosymmetryin which the twinned
edifice has a rhombohedral, wurtzite-like cell, designatedby the subscript w.

O reflections fromcrystol I. reflections fromcrystol II
subscript R deno?es
indexingon wurtzile(rhombohedrol) celtcFcl
ci.* o o r*R
D

Twinning by twin - lottice symmetry ( TLS )twin obllquitY(ar) " O
twin index (n) = 3
twin plone(O3l)
FIc. 7. Illustration of the operation of the twin law producing a rhombohedral,wurtzite-sizedcell. A full description of the twin is given in the figure. The indices(002)', (004)' and (006)' from crystal II have indices (l0t), (202) and (303) inthe wurtzite cell (using the setting for a hexagonal crystal).

THE RELATIVES OF STANNITE

685

mineral will be depeadent upon the proportion powder-diffractionapproachfromapseudocubiccellof ferrokesterite. Whereas some question thus
d:e:C.
The Pauling & Weinbaum enargite crystal has an remains as to the symmetry of the purported phase,axial ratio 2o:b:1.739:1, compared to 2b:a = several investigators have reported that a phase
1.672jinthelkunominespecimenof petrukite.As transition occurs in stannite at high temperatures.
Bernhardt(l972)determinedtlataninversionoccurs
a hexagonal cell would be possible for 2b:u :1.732:1,(C/.Schiifer& Nitschi 1977),a pseudosym- in CurFeSnSoat706oCon the basisof DTA experimetry i; o6tained by the operation of tlie twin law. ment; Duplication of this result was reportedby Lee(1972)and Bente(1974),and the latter demonstrated
tlat a cubic structure was presentat 800oCin highSresn rry RELATToNS
temperature X-ray-diffraction studies. A recent
re-investigation of the pseudobinary join
Onlyferrokesteritewillbemnsidered,aspetrukite
by Kissin (1989) also prohasnot beensynthesized.The experimentalwork of Cu2FeSnSa-Cu2ZnSnSa
Springer(197i) yrrdicatesthat abbve680oC,a com- vides indifect suppoft for the existenceof a highpiete Jolid-solution existsbelweeniron and zinc end- temperature polymorph of stannite; however, it ismembersof what he called Cu2(Fe,Zn)SnSa.On the evidently not quenchable to room temperature.
The foregoing commentssuggestthataltholgh thebasis of his findings, a solid iolution should exist
betweenkesterite and its iron analog, ferrokesterite. type specimenof isostannite of Claringbull & Hey
A miscibility gap between stannite and (1955) has here been shown to be kesteriteor
ferrokesterite-ti.ttJrii,t opensbetween680oC,begin- ferrokesterite,the possiblebut asyet undemonstrated
ning from the pure iron end-member composiiion existenceof a cubic polymorph of stannite is notand moving to more zinc-rich compositions with precluded. Studiesof material such as that from thedecreasing
iemperature.The resultsoi Kissin(1989), bachang mine, Peoples' Republic of .China'
however,indicatethat a miscibility gap betweenstan- describedby Corsini & Tanelli (1984),may yield thisnite and ferrokesterite-kesterite inteisects the soli- proof; however, the mineral must be characterized
dus of the pseudobinarysystem.Thus, although iron- by single-crystalX-ray diffraction and compositionalrich membersof a ferrokesterite-kesteritesolid solu- dara.
The existenceof ferrokesteritewas predictedontion exist, the resultsofthis study indicatethat thepure iron end-member of ferroiesterite does not the basis of experimental work by Springer (1972),
and its discoverydoesnot presentany surprisesfrom
exist, at least in the condensedsystem.
this standpoint. Moreover, its discovery, together
with the recognitionin the West of the existenceof
DrscussroN
kesterite,discoveredearlier in the USSR, explain t]te
The findings of this work have important impli- otherwise mystifying results of -Koucky (1959).
cations for loig-standing notions regarding the ita- Koucky found "isostannite" to be tetragonal bybility field of uinerals rith compositions s-imilarto single-crystal X-ray techniques and, as well, to bethat of stannite. Firstly, the concept of a stannite- rather zinc-rich, with Fe:Zn = l: l. His results, whichlike mineral with a cubic sttuct*e has a long his- could not be interpreted at that time, anticipated bytory extending at least to stannite tt of Randohr nearly thirty yeaxsthe discreditation of isostannite(194\. T'heisostanniteof Claringbull & Hey (1955), and the discoveryof ferrokesterite'
Although herereported from three different localirii. .iirii.Aited, seemedto beariut this coiriept. ii
is noteworthy that there have been few reports of ilies; petrukite appearsto be a rare mineral. Apartfrom instancesof possiblemisidentification, only one
occrurencesof isostannite, a recent one byCorsini& Tanelli (1984) notwithstanding. Significantly, other occurrenceof petrukite is known to us. Ohta
Corazza et qt. (L986) subsequently discounted theexistenceof isostannite. However, in most cases,
werebased ferrokesterite (I4)earlier reportsof isostanniteoccrurences_pgru$le ( PmnzrL
only on optical identification ofan isotropic-looking(1"',11)(Fe,-21)mineral.ThefewinstancesofX-ray.diffractioniden?d t +l ,o'Cu(l) '
tificationswereindeterminateastowhetherthe Cu(ll2ot(2)
mineral was ferrokesterileor a truly cubic mineral2s+
Cu
Cu(2) Zc
(e.9., Corsini & Tanelli 1984).
2s
Sn
+
Zb
Sn
On ttre other hand, someevidencefor a cubic poly4br S( | )s
Hffldi;'ffi,f,ilffffi"*fiJffifilT;Hi;
at 500 and 420oc,a result duplicatedcomposition
by Wang (1982). However, the phase was indexed
on a 10.85A cell, which cannot be distinguished by

2s
sc + lsizi
I s tst2o

Hc. 8. Hypotheticalpositionsof atomsin petrukite,asderivedby distortionof thosein ferrokesterite.

686

THE CANADIAN MINERALOGIST(1980)reportedon analysesof two varietiesof stanCoNcLUsIoNs
nite from the Toyoha mine, Japan. Although X-raydiffraction data were not given, the structural forThis study has demonstrated that three minerals
mula of his "stannite II" is (Cu,.sFeo.aezno.so)xz.oof stannite-likecompositionexist.Aside from stan(Sno.elr5.e3)p1.ozS:.se,very similar to those reported nite of composition Cur@e,Zn)SnSaand space
for the petrukite from the localitiesstudiedhere.This group 142m, there are the new minerals: l) Fercomposition is contrastedto that 9f "slannitg I",
rokesterite, Cur@e,Zn)SnSo,the composition ofa normal, stoichiometricstannite.Within the Toyoha which falls within the compositional range of stanmine, several indium-rich minerals, including nite; however, its X-ray powder pattern is strongly
sakuraiite and a previously unreported AgInS2 mi
pseudocubic.Single-crystalstudiesreveal that it isneral, also were described(Ohta 1980).The deposit tetragonal g4). Ferrokesteriteforms a solid solution,
appearsto be similar to the Ikuno mine on this and Cu2(Zn,Fe)SnSa,from which its name is derived, atnumerous other criteria; these xenothermal veins high temperatures.Ferrokesteriteevidently is a polyassociatedwith granitic plutons appear to be the morph of stannite. 2) Petrukiteis similar in compocharacteristicmode of ocsurrenceof petrukite.
sition to stannite; however, careful analysesreveal
The stability relations of petrukite are unknown, that stoichiometric coefficients for Cu are lessthan
but compositional relationships suggestthat indium 2.0, and for (Fe+Zn), greater than 1.0, with
substituting for tin is essentialto ensure its stabil- Cu+Fe+Zn : 3.0, and that In, althoughpresent
ity. The compositionaldata of Table 5 suggestthat in minor amounts, apparently is an essentialcomthe coupled substitution Cu+Sn = In+Zn is the ponent. Careful X-ray-diffraction studiesalso reveal
charge-balancemechanismand ensuresstoichiome- that petrukite is orthorhombic (Pmn2r). The
try of the mineral, a relationship also suggestedby mineral is believed to owe its stability to the distorShimizu et al. (1986)in their study of the ores from tion ofthe tetrahedralbondssurroundingSn due to
Ikuno mine; however, they identified petrukite as substitution by In.
stannite.
Studies of holotype isostannite, the purported
The incorporation of indium in the tin site of cubic high-temperaturepolymorph of stannite,reveal
petrukite may further be responsiblefor the reduc- that it is a memberof a kesterite-ferrokesteritesolidtion in symmetry from tetragonal for stannite and solution series.The as-yetunproven existenceof akesterite to orthorhombic. Distortion of bond cubic polymorph of stannite is not precluded.
symmetryabout the tin atom could producethe slielrt
modification necessaryto obtain an orthorhombic
structure.This processmay be demonstratedby the
ACKNOWLEDGEMENTS
following hypothetical illustration.
If ferrokesterite, with a structural formulaThis research was aided by technical assistance
Cur(Zn,Fe)SnSa(Z=2) is considered (Fig. 8), from the following at CANMET: E.J. Murray(Fe,Zn) and Cu(l) are in distinct sites,accordingto (powder X-ray diffraction), the late J.M. Stewart
the structural refinement of Hall et al. (1978). (single-crystal X-ray diffraction) and J.H.G.
Chichagov et al. (1986) suggestedan alternative Laflamme (preparation of polished sections).At
ordering schemewithin this spacegroup; however, Lakehead University the following are thanked forneither their evidencenor the refinement of Hall er their assistance:T.J. Griffith (single-crystalX-ray
al. (1978)seemto provide a definitive answerto the diffraction), S.T. Spivak (drafting) and W.C. Bons
questionof ordering. Distortion of the ferrokesterite and S.E. Millar (manuscriptpreparation). Reflecstructure due to substitution of a small amount of tivity measurementswere carried out by L.J. Cabri
In in the Sn site could produce the enargitestruc- ar CANMET (petrukite) and J. Guha at Universitd
ture, in which Cu(l) and @e,Zn) occupy the same du Qudbec d Chicoutimi (ferrokesterite). Sample
site. As Cu(l) and (Fe,Zn) are locatedin equivalent materialswere obtained from H.G. Ansell and R.
sites, a departure from the stoichiometry of l4slligan, GeologicalSurveyof Canada,A.J. Cridferrokesterite is possible,and the structural formuladle, British Museum (Natural History), and W.
of petrukite becomes(Cu,Fe,Zn)3(Sn,In)Sa.
Petruk (CANMET). Valuable discussionswere held
Shimizuet al. (1986)also describeda ,.kesterite,, with W. Petruk and H.D. Grundy, who is alsowith the structural formula (Cu,Zn,Fe)r(Sn,In)Sn. thanked for his hospitality at McMaster University,
This variant appearsto be petrukite, with Zn>Fe.
wheresomeof the final detailsof the work werecomHowever, it is found in close proximity to, if not pleted. F. Corsini, an anonymousrefereeand R.F.
actual contact with, petrukite. Thus, the minerals Martin provided valuablesuggestionsfor improvemay not be members of a solid solution; this ment of the manuscript. This work was supported"kesterite" merits full characterizationby an X-ray- initially by a National ResearchCouncil of Canada
diffraction study, as doesholotype sakuraiite from postdoctoral fellowship and later by a Natural
the same locality, as noted by Kissin & Owens Sciences and Engineering Research Council of(1986b).
Canada Operating Grant (A3814) to S.A.K.

THE RELATIVES OF STANNITE

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687

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