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Canadian Mineralogist Vol. 30, pp. 633-638(1992)
THE WODGINITE GROUP. III. CLASSIFICATION AND NEW SPECIES
T. SCOTT ERCITI, PETRIERNY eNp FRANK C, HAWTHORNE Deportmentof GeologicalSciences, University of Manitoba, Winnipeg,Manitoba R3T 2N2
ABSTRACT The minerals constituting the wodginite group are isostructural oxides, with the generalformula ABC2Oy (Z = 4);A = Mn2*, Fd*, Li, E B : Sn4*, Ti, Fe3*, Ta;C : Ta, Nb. A classificationsystembased onthe chemistry of the .,4-and B-cationsites has been devised; it useschemical modifiers in conjunctionwith the root name"wodginite". Wodginite itself has the generalformula MnSnTa2Os;two new membersof the wodginite group are charactedzed here:-ferrowodginite, F/+SnTa2Os and titanowoiginite, MnTiTa2Os. Ferrowodginite occurs as 0.01- to- 0.2-mm inclusionsin cassiteritefrom a granitic pegmatitenear Sukula, southwestemFinland. It is dark brown to black' has a dark brown streak, vitreous luster, is optically anisotropic with all n>2, and is nonfluorescent.The calculated density is 7.02 g/cm3; it is brittle, H 5%, without cleavage;it has an irregular fracture. The averagechemical composition(wt. Vo)is: MnO 2.8, FeO 9.3, Fe2O31.9, TiO2 4.3, SnO210.1, Nb2O5 14.8, Ta2O5 56.3, total 99.4.The strongestfivelines in the X-ray powderpauein-are:4.16('50),'2.g7(Aq,2.55(30i, 2.493(40\ {nd 1.a55(30)A. fne unit-cell parametersare o 9.415(7),b 11.442(6),c 5.103(4)A, B 90.8(l)', V 549.'7(6)Ar, spacegroup A/c. Titanowodginiteoccurs as euhedral,diamond-shaped crystals up to I cm acrossat the Tanco pegmatite,Bernic Lake, Manitoba. It is dark brown to black, has a dark brown streak, vitreous luster, is optically anisotropic and biaxial (+) with aJIn>2, and is nonfluorescent.The densityis 6.86 (meas.)and 6.89g/cmr (calc.);it is brittle, H 5%, with no cleavageand an irregularfracture. The chemicalcdmposition (wt.9o) is: MnO 9.0, FeO 3.1, Fe2O30.1,'fi029.2, SnO27.4, lrlb2os ll.l, Ta2O559.9, totd99.7.The strongestfive tines in the X-ray pgwdgr pallgry.are:-3.644(46\, Z.giio}A\,2:966(95),2.49566\and 1.715(23)A. Theunit-cellparametersarea9.466(2), b 11.431(l),c5.126(l) A, p g}.3lQf , V 554.6(l) A3; the spacegroup is A/c.The classification,the new speciesand their nameswere approved for publication by the I.M.A. Commissionon New Minerals and Mineral Names' Keywords: ferrowodginite, titanowodginite, wodginite, new mineral species,oxide, granitic pegmatite, Finland, Manitoba. SoMMAIRE Les min6raux du groupe de la wodginite sont des oxydesisostructuraux ayant la formule gdn6raleABC2O8 (Z = + * + 4); I repr6senteMn2 , Fe2+, Li et deslacunes, B repr6senteSn4 , Ti, Fe3 et Ta, et C, Ta et M. Nous proposons un systbmede classificationfond6 sur I'occupation des positions A et B; il se sert de qualificatifs et de Ia racine "wodginite". La wodginite proprement dite a la formule MnSnTa2O3.Nous ddcrivonsici deux nouveauxmembres de ce groupe, ferrowodginite, Fd+SnTarOr, et titanowodginite, MnTiTa2O6. La ferrowodginite forme de petites inclusions(0.01-0.2 mm) dansla cassit6rited'une pegmatitegranitique pris de Sukula,dans le sud-ouestde la Finlande. Les cristaux sont brun fonc6 ir noir, ont une rapre brun fonc6 et un 6clat vitreux; ils sont optiquementanisotropes, tous les indices n 6tant sup€rieursd 2, et non fluorescentes.La densit6calcul6e est de 7.02; la ferrowodginite est cassante(fractures irrdgulibres); sa duret6 est de 5%, et elle est sansclivage. La composition chimique moyenne(90, en poids)est: MnO 2.8, FeO 9.3, Fe2O31.9, TiO2 4.3, SnO210.1, M2O5 14.8,Ta2O5 56.3, total 99.4.Lescinq raies les plus intensesdu clich6de poudre [d en A(I)] sont: 4.16(10),2.97(100),2.55(30), 2.493(40) et 1.455(30).Les parambrresrdriculaires sont: a 9.415(7),b 11,442(6),c 5.103(4)A, p 90.8(l)', v 549.7(6)Ar, groupespatial a/c. La titanowodginite forme des cristaux idiomorphes en losangesd'un cm dans la pegmatite de Tanco, lac Bernic, au Manitoba. Les cristauxsont brun fonc6 A noir, la rayure, brun fonc6, et l'6clat, vitreux; elleest optiquement anisotrope et biaxe positive, avectous les indicesde r6fraction sup€rieursd 2, et non fluorescente.La densit6est 6.86 (mesu1€e) et 6.89 (calcul6e).Elle estcassante; sa duretdest de 5%. Elle ne montre aucun clivage,et les fracturessont irr6gulibres. La compositionchimique (90, en poids)est: MnO 9.0, FeO 3.1, Fe2O30.^1, TiO2 9.2, SnO, 7.4, Nb2O511.1, Ta2O5 59.9,total 99.7.Les cinq raiesles plus intenses du clich6de poudre[d en A(I)] sont:3.644(46),2.976(100),2.966(95), 2.495(36)et 1.715(23).Les paramdtres r6ticulaires sont a 9.466(2),b ll.43l(l), c 5.126(l) A, B 90.31(2)', V 554.6(l) 43, groupe spatialA./c. Le sch6made classification,les espdcesnouvelles et leur nom ont recu I'approbation de la Commissiondes nouveauxmindraux et des noms de min6raux de I'Association lnternationale de Min6ralogie. (Traduit par la R6daction)
Mots-cl6s:ferrowodginite, titanowodginite, wodginite, nouvelle espbce mindrale, oxyde, pegmatite granitique, Finlande, Manitoba.
lPresentaddress: Mineral SciencesDivision. CanadianMuseum of Nature, Ottawa, Ontario KIP 6P4.
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INTRODUCTIoN difficulty involved in obtaining actualsite-occupan- cies by means other than crystal-structure analysis Although wodginite was first encounteredby or highly precise powder diffractometry, a clas- Simpson (1909) at Wodgina, Western Australia, sification based on the fully ordered formulae recognition of its status as a new mineral species seemsmost practical (c/. the columbite group). 3) came only when Nickel et al. (1963\ showed it to Coupled substitutionsinvolving more than one site be distinct from tantalite. Recognition of this result in further complexity, as does the introduc- distinction led to the discoveryof wodginite at a tion of some substituents by more than one variety of localities, which today total 37 in mechanism (e.9., B-site Ta). However, these number. mechanismsare well known (Ercit er al. 1992.a\,so Nickel el al. (1963)correctly inferred wodginite that by applylng constraints to the rules of to be a superstructureof ixiolite; however, it was nomenclature,a solution should be possible.Table not until much later that the detailsof the structure I summarizesall known operators. of wodginite and its formula were deciphered Taking all of the above factors into considera- @ergusonet ol. 1976).Wodginite has the general tion, the following scheme is proposed for the formula ABC2O8,ideally .4 = M[, B = Sn and classification and nomenclatureof wodginite-group C = Ta, with Z : 4 and space group C2,/c. minerals basedon A- ard B-site chemistries: Wodginite showsconsiderable solid-solution at all 1. The set of specieswith the wodginite structure structural sites (e.9., von Knorring et al. 1969, (pafiially to completelyordered, Ercit et al. 199?-a, Kornetova et al. L918). We have found some b) is referred to as the wodginitegroup. samplesto deviate by more than 5090 from the 2. For historical reasons, the name wodginite is ideal formula; hence "wodginite" as previously usedfor end-memberMnSnTa2Os, which is closest defined inadequatelydescribes these samples.As to the composition of most natural wodginite- previously defined, "wodginite" consists of a group minerals. group of mineral species.The classificationand two 3. Species names are to consist of the root new membersof the group are the subject of the "wodginite" modified by prefixesreflecting.,4- and present paper; the structural crystallographyand B-site chemistries. crystal chemistry of the group are described in 4. Such prefixesare to be usedonly in caseswhere companion papers@rcit et al. 1992a,b). one or more of the operatorsin Table I are more than 5090effective. ClassrrtcanroN 5. No more than one prefix per site should be used to construct the name, in which case the 1-site The name wodginite, as introduced by Nickel et prefix should precedethe 8-site prefix. In cases al. (1963)and defined by Fergusonet al. (1976),is where more than one constituent is introduced to associatedwith the composition MnSnTarOs. As a single site by the operation, the prefix chosen such, the name is inappropriate for severalnatural should reflect the unique constituentonly. examplesof wodginite that deviate by more than The following examplesshould serveto illustrate 50r/o at individual cation sites from this ideal the applicationof point 5. Ta is a non-uniqueB-site composition. These examplesof wodginite most constiluent in that it can be introduced to the site closely approach the hypothetical end-members by as many as four different mechanisms of FeSnTa2Os,MnTiTa2O6 or LiTaTa2Os. substitution (operators4 to 7 qf Table 1). One of Subdivision and classification of wodginite- these operators is always insignificant from a group minerals are complicated by a number of taxonomicpoint of view, and thus it can be ignored factors. l) Cation substitutions involve three (operator 7). Of the remaining operators, (5) distinct sites,making a nomenclaturebased on the representsthe only one by which Fe3+ can be genericname wodginite diffrcult. However,because introduced to the .B site. Fd+ is the unique of the limited extent of Nb substitution at the C site (
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TABTE2. CLASSIFICAIIONOF THEIODGINITE GROUP (1966)and the existenceof some natural samples Crlterla with Fe3* contentsapproaching 5090 efficiency of l{afie End Mmbsr /4slte I slte the operator (5) suggest that operator (5) may 35C/ Tl TODEIIITE tiln4Sn4Tas0? generatenew speciesin the future. s257"Fe* The classification scheme was approved for 350%[l, >50%Tt TtTtNrfoDstfitrE ilnaTiala8ot publication by the International Mineralogical s50% Fob Association in 1984, and is presentedhere, in its >25%Ferr >25%'lal ( unnaned) Una(Fe}zTa2)Ta8q2 original systematics,with only minor additions isc/ Ti (Table l) imposedby more recentstudies (Voloshin FEnnomDotfttTE Fe&4Sn4T&Oja s25% Fe]+ et al. t990). >5@ Fe& >50%Tt (unnmed) FealTl oTae0f FrnnowopctNltr >?5% Fee (unnmd) ( >25%Ia) Fe&a Fe?2Ta2)Tas0e >5ezLt >50%Ta LIIt|IflODSITITE LlcTaa'I Ferroan "varieties" of wodginite were first encounteredby Vorma & Siivola (1967) and von Knorring et al. (1969)soon after wodginitewas first establishedas a species.The latter of these two samplesis only a variety of wodginite, but the constituentof this operation, thus the appropriate sampleof Vorma & Siivola (1967)is wodginitewith prefix for greater than 5090 effectivenessof (5) is more than 5090 of its Mn2+ replacedby Fe2+.We ferri, As already correctly applied by Voloshin er obtainedsamples of this material from the research al. (1990), lithio is the prefix associated with collectionof J. Siivola (sampleA5234, renumbered operator (4). And so, by deduction, tontolo would SK-l in the presentstudy), and found that it is a be the prefix associatedwith greater than 5090 new species,the Fd+ analogue of wodginite; in efficiency of operator (6). allusion to the chemistry, we name the species Table2 gives actual and hypothetical namesof fenowodginite. The new speciesand its name have speciesand end-membercompositions generated by been approved for publication by the I.NI.A. operators(1), (2), (a) and (5), the most significant Commissionon New Minerals and Mineral Names. operators involved in the crystal chemistry of the Ferrowodginite occurs in a granitic pegmatite group. Criteria for classification follow the rules near the village of Sukula in the Tammela-Somero given above. The table is divided into three pegmatiteprovince, southwesternFinland (Vorma segmentson the basis of ,4-site chemistry. The & Siivola 1967),the regional geologyof which was uppermost segment contains species with Mn describedby Aurola (1963).Because of the number end-members.The middle segmentcontains species of pegmatitesin the vicinity of Sukula, and owing with Fd* end-members. The bottom segment to impreciselabeling of the samples(collected over containsthe only speciespossible with Li end-mem- 100 years ago), the exact location is not known. bers. Three new membersof the wodginite group However, Vorma & Siivola (1967) indicated that have been recognized: ferrowodginite and samplescontaining the mineral probably originated titanowodginite (presentstudy) and lithiowodginite from a quarried pegmatite near the Makitulokas (Voloshin et al. 1990). At an earlier stage of this farm house in Sukula, where tantalian cassiterite work (Ercit et al. 1984), a fourth species was ("ainalite"), an associateof the ferrowodginite, proposed:tantalowodginite. We havesince formal- was originally found. ly retracted the speciesstatus of tantalowodginite, Samples consist predominantly of granular as we now recognizethe type samplesto be Ta-rich aggregatesof strongly color-zoned tantalian cas- wodginite and lithiowodginite. Greater than 50Vo siterite, with individual grain-sizes ranging from I effectivenessof operator(6) (Table l) is shownonly mm to a few cm. Tapiolite, native bismuth and by sample L-15 @rcit et al. 1992a);however, the ferrowodginiteoccur asinclusions in the cassiterite. minute sizeof the crystalsand the limited quantities Stannomicrolite(originally "sukulaite"; Vorma & of the mineral do not allow for measurementof Li Siivola 1967) occurs as a replacement of the or the X-ray properties of the sample; henceit is ferrowodginite @rcit et ol. 1987). rot presentlypossible to use "tantalowodginite" as The ferrowodginite inclusions in cassiteriteare a speciesname. Two samples examined in the typically 0.01 to 0.2 mm long; however, grains as present study (TSE-82, TSE-94) have more than large as 0.3 mm have been found. The inclusions 5090 of the end-member FeTiTa2O6;however, we observed are irregular in shape; however, becauseof the minute sizeof eachsample, adequate Vorma & Siivola (1967) also observedinclusions material is not available for characterization of the with lath-like outlines. Stannomicroliterims about hypothetical species"ferrotitanowodginite". As a the ferrowodginite inclusions are typically in the final note, both the synthesiswork of Turnock order of l0 am thick.
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Ferrowodginiteis dark brown to black, and has TABLE4. X.RAYPOI{DER.DIFFMCTION DATA FOR NEI{ I,IODGINITE-GROUP MINERALS a dark brown streak. It is iransparent to trans- lucent, nonfluorescent,and has a vitreous luster. It is anisotropic, and is assumedto be biaxial; all d (ca ofits indicesofrefraction are greaterthan 2.0, and 200 4.71 4.73 could not be measuredwith available immersion uI 1'?9I 4.16 4.20 oils. lll 9. ro _, 4.18 It is brittle and hasa hardnessof 5 /z;-it shows 220 3.64 3.64 3.645 s.iiq ;; no prominent cleavage, but has an irregular 130 3.530 2 221 2.98 I z''' 2.917 2.976 t00 fracture. Because of the small grain-size and 22t z.ssI a.loa 2.966 95 040 2.86 2.86 2.858 2.858 15 intimate association with stannomicrolite, the 002 2.55 2.55 2.563 t5 041 2.495 2.493 2.496 2.495 36 density of ferrowodginite could not be measured; 400 2.354 2.352 z.Joo 2.366 8 the calculateddensity is 7.02 g/cm3. 202 2.256 2.259 2.260 3 24t 2.198 2.205 2.203 5 Energy-dispersion (ED) 222 2.099 2.101 2.10t I X-ray spectra were 222 2.078 2.O92 2,094 7 obtained with a MAC 5 electronmicroprobe using 042 1.905 t.905 1.908 1.907 8 440 1.8t7 1.823 1.822 7 a Kevex Micro-X 7000 spectrometer.Spectra were 260 t.761 1.768 t.767 t.767 17 collected for 200 live secondswith 402 1.742 1.742 1.741 1.743 8 an operating 441 1.720 1.720 1.720 16 voltage of 15 kV and a sample current of 5 nA 402 l.ll3) 1.734 1.733 7 (measured 441 l./uo 1.715 1.715 23 on synthetic fayalite), and were cor- 223 1.547 I t.sa; 8 223 1.534 1.545) rected for current and voltage drift. Line overlaps 442 1.488 1.488 l.489 2 suchas TaM6 andTaMq on NbZa, SnZBon TiKcv, 442 1.473 !.48? 1.481 3 621 l'1:9] r.45s 1.460 r.462 16 and Mnl(B on FeKa weredealt with by noniterative r.9to _, 1.456I t.css 18 262 1.449 1.449 1.454) techniquesof spectral stripping involving library 080 1.430 1.429 1.430 2 spectra of individual elements.Manganotantalite 081 r.377 1.378 l.J/o r.377 7 a (A) 9.415(7) e.466(2) (Mn,Ta), chromite (Fe),titanite (Ti), cassiterite(Sn) b u.442(6) ll.43l(1) c 5.103(4) 5.126(1) and CaNb2O6(Nb) were used as standards.Data p ('.) e0.8(1) e0.31(2) were reduced with Kevex software using the y (Ar) 54s.7(5) 5s4.6(l) programMAGIC V (Colby F" 1980). radlatlon, conected for shr'lnkage. investigation Tl tanowodgini tet Phi'llps Ptll050diffractoneter, Nl-fi ltered Cu(a Qualitative of ED spectraand two radlatlon, CaF?internal standard. quantitative analysesshowed no significant core- to-rim or grain-to-grain variations. The averageof the two chemicalcompositions is given in Table 3. The Fe2+:Fe3+ratios werecalculated according to the method of Ercit et al. (1992a). The average unit-cell contents (Fe2+r.*Mno.r:flo.o:)>o are: : (Sn1.56Ti1.27Fe3* Ferrowodginiteis ideally Fe2+SnTarOr,Z 4, and o.ssTfu.oo)ra(Ta5.3sNb2.6)"rOr2 is the ferrous iron analogueof wodginite. The ferrowodginite is anhedral. Optical ex- amination showsit to be polysyntheticallytwinned; a X-ray precessionstudy showsthat the twin plane is [l00]. IABLE 3. CHEIIICALC0l.lPostTl0NS 0F NEt'lCoDGINITE-GR0UP ttINERAtS X-ray precessionand powder-diffraction studies Ferrorodglnlte* Tltanowodglnite (sK-l) (A-25) show ferrowodginite lo be isostructural with (core) (rlm) wodginite; the powder pattern is given in Table 4. iln0 wt.Z 2.8 9.0 F€0 9.3 3.1 2.5 The data were obtained on the samecrystal as was Fe20j lo 0.1 Ti02 4.3 9.2 8.0 usedfor microprobe analysis;because of the small Sn02 10.1 7.4 8.3 size of the crystal, the mean ratio of line intensity Nb?05 14.8 ll.1 I l.l Taz05 60.3 to background was found to be low; henceseveral 99.4 99.7 100.3 weak lines normally found in wodginite patterns Catlons per 32(0) were not observed.The unit-cell parameterswere Mn 0.93 a.tJ refined using the program CELREF (Appleman & Fe2' 3.04 noo 0.79 Fe* o.02 0.14 Evans1973): a 9.415(7),b l\.442(6),c 5.103(4)A, TI t.27 z. ob 2.32 5n t.5u I .14 r.2a B 90.8(l)", V 549.7(6)A3. In generaltype Nb 2.62 1.94 qoq ferrowodginite has smaller a and b cell edgesand tE ot 15.94 0 angle, and a larger c cell edge than wodginite. Fe2.:Fe$calculated accordlngto Erclt et al. (1991b). On the basis of the resulrsof Ercit et al. (1992a), " Average of 2 analyses. the type sampleis fully ordered.
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TITANowoDGINITE The methods used to analYze tYPe titanowodginite are identical to those .used for Titanium is largely a ubiquitous component in ferrowodginite.Results of the chemicalanalyses are wodginite-groupminerals; however, Ti contentsare givenin Table 3. Type titanowodginiteshows slight typically low, generallyless than I wt.9o TiO2. The core-to-rim variation in chemistry. The rim has first Ti-rich variety of wodginite encounteredwas higher Mn/Fe and Sn/Ti than the core, typical of the type ferrowodginitesample, with an averageof normal chemical zoning in oxide minerals from 3VoTiO2 (Vorma & Siivola 1967).Grice et al. (1972) granitic pegmatites(Cernf & Ercit 1985).In accord- describedwodginite with up to 4t/o TiO2 from the accordancewith the procedureof formula calcula- Tanco pegmatite, Manitoba. This remained the tion of Ercit et ol, (1992a),the formula contents maximum Ti content of wodginite until a re-ex- per unit cell are: (Mnr.onFe2+o.esn o.or)r+ + amination of the Ta-, Nb-oxide minerals at Tanco (Ti2.aeSn1.21Tq.22Fe3o.os)r4(Ta6.6uNbr.errsO32. led to the discoveryof wodginitewith TiO2 contents Titanowodginiteis ideally MnTiTa2Os,Z = 4, and as high as l0.4Vo (Ercit 1986).In this material, up is the titanium analogueof wodginite. to 73 at.Vo of the Sn is replacedby Ti; hence it Titanowodginite is euhedral. Predominanceof representsa new specieswhich, in allusion to its the form {ll1} results in the characteristically composition, we have named titanowodginite.The bipyramidal crystals; occasionally the [101] and new speciesand its name have been approved for {100} forms are prominent. Penetration twins are publication by the I.M.A. Commissionon New typical, with {001} and {100} as the composition Minerals and Mineral Names. planes. Type titanowodginite occurs in a sample"of Ta X-ray precessionand powder-diffraction studies ore from the research collection of P. Cern9, show titanowodginite to be isostructural with sampleA-25. The samplecomes from the workings wodginite; the powder pattern is given in Table 4. of the Tanco pegmatite, Bernic Lake, Manitoba; Using the CELREF progr€rm,the refined unit-cell the regional geology of the area and the internal parametersare a 9.466(l), b ll.43l(l), c 5.126(l) structure of the pegmatitewere reviewedby Cernf A, g go.st(z)", v 554.6(l) A3. In general,type (1982).From the mineralogy of the host rock and titanowodginite has smaller a and D cell edgesand the chemistry of its oxide minerals, the sample is I angle, and a larger c cell edge than wodginite. inferred to come from exposuqgsof the sac- On the basis of the results of Ercit et ol, (1992a), charoidalalbite unit lunit (3) of Cernj' (1982)]in the type sampleis only 3590 ordered; the absence the easternworkings of the pegmatite.The mineral of severalhigh-d lines in the diffraction pattern is occurs with microlite and manganocolumbiteas in part due to this disorder. disseminationsin a silicate matrix consisting of saccharoidalalbite plus quartz with minor mus- SUMMARY covite and beryl. Since the discovery of the type sample,titanowodginite has been found in several (1) The wodginite group consistsof isostructural exposuresof the saccharoidalalbite unit in the minerals of the general form ABCtOt (Z = 4), A eastern workings of the pegmatite, and in one : Mn2*, Fe2*,Li, z; B = sn4+,Ti, Fe3+,Ta; c exposureof the central intermediateunit lunit (6) : Ta, Nb. of Cern! (1982)lin the northwesternworkings of (2) A schemeof classificationand nomenclatureis the pegmatite. introducedwhereby species are describedby names Type titanowodginite occurs as euhedral, involving chemical modifiers used in conjunction bipyramidal crystalsranging from a few mm to I with the root name "wodginite". cm long. It occurs most often in irregular clusters (3) There are four wodginite-group minerals of crystals,but also occursas individual crystals. known: (i) wodginite (sensustricto), ideally MnSn Titanowodginiteis dark brown to black and has TaOr, (ii) ferrowodginite, ideally Fd+SnTa2O8, a dark brown streak. It is transparent to trans- (iii) titanowodginite, ideally MnTiTa2O6,and (iv) lucent, nonfluorescentand has a vitreous luster. It lithiowodginite, ideally LiTaTa2Os. is anisotropic,biaxial (+); all of its indices of (4) There is extensivesolid-solution toward the refraction are greater than 2.0 and could not be hypothetical end-members ferriwodginite, measuredwith immersionoils available.It is brittle, Mn (Fd+rTa)TasO32, and ferroferriwodginite, hardness5i/2, and shows no prominent cleavage, Fd+4(Fe3+2Ta2)Ta6O32,and other species seem but has an irregular fracture. The density was probable. measuredwith a Berman balanceusing toluene as an immersion liquid. Three repeatedweighings of ACKNOWLEDGEMENTS an 1l-mg fragment gavea densityof 6.86(3)g/ cm3, which compareswell with the calculateddensity of We thank Dr. J. Siivola for the loan of the 6,89g/cm3. samplethat was found to host type ferrowodginite,
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and to the Tantalum Mining Corporation of stannomicrolile, Neues Jahrb. Mineral., Monatsh., Canada Limited for accessto the workings of the 249-2s2. Tanco pegmatite during the period of study. Financial support for the study was in the form of HawruonNe, F.C. & tenxY, P. (1992b):The wodginite group. I. Structural crystallography.Car. a NSERC operating grant and Tantaluln Mining Mineral.30. 597-611. Corporation of Canada contract to ft, and a NSERC PostgraduateScholarship and University Fencusox, R.B., HewrHonNs, F.C. & Gnrce, J.D. of Manitoba fellowship to TSE. (1976):The crystal stmcturesof tantalite, ixiolite and wodginite from Bernic Lake, Manitoba. II. REFERENCES Wodginire. Can. Minerol. 14, 550-560.
AreLEMAN,D.E. & EveNs, H.T., Jn. (1973): Job Gnrcn, J.D., CenNv,P. & FencusoN,R.B. (1972):The pegmatite 9214:indexing and least-squaresrefinement of powder Tanco at Bernic Lake, Manitoba. II. pseudo-ixiolite diffraction data. U.S. Geol. Sum., Comput. Contrib. Wodginite, tantalite, and related ?.0(NTIS Doc. PB2-r618E). minerals. Can. Mineral. ll, 6N-642. VoN KNoRRING,O., SeHaMa, T.G. LEurrNrN, M. AuRoLA,E. (1963):On the pegmatitesin the Torro area, & (1969): Ferroan wodginite from Ankole, south-west southwestern Finland. Bull. Comm. gdol. Finlande 2M, l-32. Uganda. Bull. Geol. Soc.Finland 41,65-69. KonNnrove, V.A., SroonrNKo,C.A., KAzAKovA,M.E., denNY, P. (1982):The Tanco pegmatiteat Bernic Lake, TnoNrvn, N.V, & BoyARsKAyA,R.V. (1978):Iron- southeasternManitoba. Granitic pegmatites in nlr rich wodginite. Tntdy Minerol. Museyo Akad. Nauk Scienceand Industry (P. Cernf, ed.).Mineral, Assoc, SSSR27, 75-85(in Russ.). Can., Short-CourseHandbook 8, 527-543. NrcxrL, E.H., Rowr-aND,J.F. & McAnau, R.C. (1963): & ERcrr, T.S. (1985): Some recenr Wodginite - a new tin - manganesetantalate from advancesin the mineralogy and geochemistry of Nb Wodgina, Australia and BernicLake, Manitoba. Can. and Ta in rare-element granitic pegmatites. ttl/. Mineral. 1,390.402. Mindral. 10E,499-532. SIMpsoN,E.S. (1909): Further occurrencesof tantalum CoLBy, (1980): - J.W. MACIC V a computer program and niobium in WesternAustralia. Aust, Assoc,Adv, quantitative for electron-excited energy dispersive Sci.12,310-315. analysis. /n QUANTEX-Ray Instruction Manual. Kevex Corporation, Foster City, California. TuRNocK,A.C. (1966):Slnthetic wodginite,tapiolite and tantalite. Can. MineraL 8. 461470. Enctr, T.S. (1986): The Simpsonite Paragenesis. The Crystal Chemistry and Geochemistry of Extreme Ta VoLosHrN, A.V., PerHouovsrrr, YA.A. & Fractionotion. Ph.D. thesis, Univ. Manitoba, Win- Barucursenarrsrv, A.Yu. (1990):Lithiowodginite - nipeg, Manitoba. a new mineral of the wodginite group from granitic pegmatitesin easternKazakhstan. Minerol. Zh. 12, CrnNf, P. & HawrHonNe, F.C. (1984): 94-100.(in Russ.). Wodginite crystal chemistry. Geol. Soc.Am., Absff. Progroms 16, 502. Vonue, A. & Suvola, J. (1967): Sukulaite - Ta2Sn2O7 - and wodginite as inclusions in cassiteritein the - & McCaruuoN, C.A. (1992a): granitepegmatite in Sukula,Tammela in SW Finland. The wodginite group. II. Crystal chemistry. Can. C. R. Soc. gdol. Finlonde 39, 173. Mineral.30, 613-631. ReceivedJune 26, 1991,revised manuscipt acceptedMoy & Sttvota, J. (1987):The compositionof 21,1992.
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