American Mineralogist, Volume62, pages403410, 1977

Classificationand nomenclatureof the group

D. D. HoclnrHl Departmentof Geology,Uniuersity of Ottawa Ottawa,Canada Kl N 6N5

Abstract

The IMA Subcommitteeon Nomenclatureof the PyrochloreGroup recommendsthe following classificationand nomenclature: Group pyrochlore[Ar-.B,O6(O,OH,F)r-".pHzO] Subgroups pyrochlore,, Species pyrochlore,kalipyrochlore, bariopyrochlore, yttropyrochlore, ceriopyrochlore, plumbopyrochlore, uranpy- rochlore(pyrochlore subgroup); microlite, stannomicrolite, bariomicrolite, plumbomicrolite, bismuto- microlite,uranmicrolite (microlite subgroup); yttrobetafite, plumbobetafite, betafite (betafite subgroup). Subgroupsare divided according to B-atoms(Nb, Ta, Ti) andspecies according to,4-atoms (K, Sn, Ba,REE, Pb,Bi, U). Forty-eightnames related to the pyrochloregroup should be dropped,and fivetype specimens should be reinvesti- sated.

Introduction burg et al. (1960), van der Veen (1963),and Bon- The pyrochloregroup comprisesa seriesof cubic shtedt-Kupletskaya(1966). Adding to this growing oxidescontaining essential amounts of ,tan- complexity,the literaturecontinued to perpetuate "species" talum,or .Pyrochlore itself was described by rnineral of questionablevalidity, such as Wdhlerin 1826,microlite by Shepardin 1835,and blomstrandite,ellsworthite, and chalcolamprite,and "hatchettolite"by Smith in 1877.The remaining synonymssuch as mendeleeviteand betafite, neo- memberswere all describedin the presentcentury. and microlite, koppite and pyrochlore. Prior to the late 1950's,Dana's Systemof Miner- Clearly a need existed for a universallyaccepted, alogy(Palache et al.,1944,p.747-757)provided the rationalclassification and a revisednomenclature. acceptedclassification of the pyrochloreminerals. In In viewof thisneed, the IMA Commissionon New thisclassification pyrochlore-microlite was described Mineralsand Names,at the requestof the as a series,and ninesimilar were appended chairmanDr. MichaelFleischer, established a Sub- as"likely members"of thisseries. Betafite and "djal- committeeon PyrochloreNomenclature. A. H. van maite"(ibid, p.803-805) were excluded, but with the der Veen, Arnhem, Netherlands, was appointed cautionarystatement that "considerableuncertainty" chairmanin August, 1966,and he, in turn, selected existsconcerning their relationshipwith pyrochlore the followingmembers: and microlite.These two mineralswere later shown, chemicallyand structurally,to retainthe pyrochlore (l ) Subcommittee,uoting members structurewith manyof the largercation sites unfilled E. M. Bonshtedt-Kupletskaya,Moscow, (Borodinand Nazarenko,1957; Hogarth, l96l). U.S.S.R.' In the 1960sand 1970smany newanalyses of py- T. Deans,London, England (Secretary)g rochloreminerals were published, revealing a wide M. Gasperin,Paris, France rangeof compositionsand leading to manynew min- D. D. Hogarth,Ottawa, Canada eral names.In the sameperiod severalschemes ofl Akira Kato, Tokyo, Japan classificationwere proposed including those of Ginz- L. Van Wambeke,Brussels, Belgium

'For the IMA Subcommitteeon Nomenclature of the Pvro- 'zDiedJuly, 1974 chlore Grouo. 3 Retired Feb., 1976 403 404 HOGARTH: THE PYROCHLORE GROUP

(2 ) Commissionobseruers, non-uoting MicroliteSubgroup in whichNb * Ta ) 2Ti and > M. Fleischer,Washington, D.C., U.S.A. until Ta Nb, in which2Ti > Nb t Ta. Feb.,1968 BetafiteSubgroup limits for the subgroups C. Guillemin,Orl6ans, France The abovecompositional of a naturalclustering of com- M. H. Hey,London, England since Feb., 1968 wereadopted because positionsand a relativescarcity of titanium-richanal- The Subcommitteefunctioned almost entirely by yses(see Fig. I ). Titanium-richspecies range from 33 correspondence.In general,their criteriawere based to 55 percentTi, whereNb * Ta + Ti : 100atom on publishedinformation, but in two cases,members percent.Analyses reporting larger amounts of tita- re-examinedtype specimens.Certain decisionsre- nium may representmixtures. In contrast,most py- quireda vote,and in the fewinstances when opinions rochloresand microlitesfall in the range70-100 per- of memberswere equally divided, the chairmancast cent Nb and Ta, respectively.Subdivision of the the decidingvote. pyrochloregroup accordingto the predominanceof At the outset,members were faced with the choice Nb, Ta, and Ti atomswould thereforerestrict the of recommending"orthodox" names,often well-es- titaniumsubgroup to fewexamples, and would cause tablishedand of deservingorigin, or appropriate wide variationsof compositionsin the pyrochlore chemicalnames. After detailedconsideration, the subgroup.Accordingly, it was eventuallyruled that Subcommitteeand later the Commissionruled in any mineralwith 2 Ti > Nb * Ta belongsto the favor of a chemicalnomenclature. betafitesubgroup. The Subcommitteesubmitted its first completere- Within the subgroups,individuals species are de- port to Dr. Fleischerin December197 1. He, in turn, finedwith respectto,4-atoms (uiz Na, Ca, K, Sn,Ba, distributedcopies to affiliatedsocieties for comments REE, Pb, Bi, U) in the followingmanner: and suggestions,which wereforwarded to the Sub- (a) Na-Ca members. or ,but no committeein November1973. A revisedreport was otherl-atom, shallexceed 20 percentof the totall- thensubmitted in Augustl9'74, and its recommenda- atomspresent, and tions were ratifiedby the Commissionin 1975and (b) other members.One or more l-atoms other 1976.The presentreport summarizesthe reportsof thanNa or Ca shallexceed 20 percentof the total l- the Subcommittee(unpublished, prepared by T. atomspresent. Deans),incorporates suggestions and decisionstaken The figure 20 percentcorresponds favorably with by the Commission,and representsthe final con- recentpractice in describingbetafite, uranpyrochlore, clusionsof the Subcommittee. and uranmicrolite,the most common speciesafter pyrochloreand microlite. Classification Theproposed classification is basedon totalI -ions The pyrochloregroup comprisesthose multiple (excludingoxonium), not on l-sites available.Thus cubicoxides having the followingcharacteristics: deficiencyof l-cations or filling of vacantl-sites by (a) essentialamounts of niobium,, and oxonium doesnot affectthe classification. titanium,either individually or in combination, Specialrules apply in the caseof lanthanidesand (b) the spacegroup Fd3m, yttrium. Although no exampleis known in the py- (c) the pyrochlorestructure as defined by Gaertner rochlore group of a singlerare-earth element ex- (1930)and Brandenberger (1931), and ceeding20 percentof thel-atoms, severalrare earths (d) the general formula Ar--B2O6(O,OH,F),-o may occur togetherin significantamounts. When 'PH,O' their total exceeds20 percentof the total l-atoms, In the caseof metamictminerals, compositional the Subcommitteerecommends that the mineral be equivalentswhich producethe pyrochlorephase on given separatespecies status. The well-knownten- ignition(preferably in vacuumor inert atmosphere) dencyfor the rareearths to be predominantlyof the are admittedto the scheme.Isostructural minerals, cerium group (light lanthanidesLa - Eu, styled suchas antimonates of thestibiconite series and tung- ECe), or theyttrium group (Y * heavierlanthanides statesrelated to ferritungstite,are excluded. Ga - Lu, styledtY), alsoprevails, and has created a Threesubgroups are recommended,based on the furthertwofold subdivision. atomicproportions of the B-atomsNb, Ta, and Ti. and species The recommendedsubgroups are: Nomenclature PyrochloreSubgroup in whichNb * Ta ) 2Ti and The current 16 speciesof the pyrochloregroup Nb ) Ta, recommendedin this studvare listedand definedin HOGARTH: THE PYROCHLORE GROUP 405

Table 1. Their namesreflect the decisionto adopt chemicalnames in preferenceto "orthodox" names. Thus uranpyrochlorereplaces hatchettolite, uran- microlite replacesdjalmaite, etc. Applicabilityof the Levinson nomenclature(Levinson, 1966) was re- ferredto, but not recommendedby theCommission. The root namesfor speciesof the Nb- andTa-rich subgroups,as alsothe namesof the subgroupsthem- selves,are derivedfrom the "orthodox" namesof the Na-Ca members.However, as no Na-Ca member has been definitely establishedfor the Ti-rich sub- group,the Subcommitteerecommends that betafite, the mostcommon member, be usedas root namefor this subgroup. The bismuthomicroliteof Zalashkovaand Kuk- harchik(1957) was considered as a new speciesbut rejectedby the Subcommitteebecause it contained Nb Ta pyrochloregroup. insufficientBi(4 atom Voof the ,{-ions). The Sub- Fig l. The threesubgroups of the Composi- tions are plottedatomically from data in Bonshtedt-Kupletskaya committeerecommends this name be used for the ( 1966).Minerals no longerincluded in thegroup (minerals with the bismuthmember of the microlitesubgroup as defined samiresitephase, "hatchettolite" from Hybla, Ontario, and "ti- in the precedingsection and first described(as west- tanpyrochlore"from Tangen,Norway) are not plotted. grenite)by Knorring and Mrose(1963). The use of additionaladjectival prefixes is op- tional, and should normally be restrictedto the with the approvalof the Commission,six newnames A-atomnext in abundanceafter thb principalcon- are introduced: kalipyrochlore,bariopyrochlore, stituent,following Palache et al. (1944,p. 43).Thus yttropyrochlore,ceriopyrochlore, stannomicrolite, bariopyrochlorefrom the type localitycan be called and bariomicrolite.Bismutomicrolite is redefined. strontianbariopyrochlore (Ba 44Vo;Sr 32Voof theA- atomspresent). Speciesof the pyrochloregroup Recommendednames are given below. Note that, Pyrochlore (Wcihler, I 826)

Tablel. The pyrochloregroup

SUBGROUPSdeflned by B atoms PYROCHLORE MICROLITE BETAF I TE viz Nb, Ta. Tt Nb+Ta>2Tl NH Ta>2Ti 2 Tt >Nb+ Ia Nb>TT Ta>Nb

Na+Ca, but no other A-atons >202 total A -atons pyrochlor nicrolite

SPECIES deflned by A -atohs kallpyrochl vaz K,Sn,Ba,REE, one or more A-atons, other Pb,Bi,u than Na or Ca, >202 rotal A-atoms stannonicrollte

Species naoed by nost abundant A -aton, other Ba bariopyrochlore ba! ionic!oIite than Na or Ca

REE* yttropyrochlore (tY>tCe)*x yttrobetaf 1te (tY>tCe) ceilopyrochlore (XCe>tY)

Pb p lunb opyr och 1o re Plunbonlcrolite Plumbobetafi

Bi b isnu Eomlcro lit

U uranpyrochlo re ur anmic r o 1l t betafite

y .|.REE= a 1La + lu), and 6dL puLpoaaa06 apecio4 detltuitioft, REEcoun-tt M oftL A-etom. " lY - Y + lcd - Lul; LCe = La + Eu. HOCARTH: THE PYROCHLORE CROUP

Kalipyrochlore (described but not named by Van Ceruranopyrochlore(Lin et al., 1973)is a cerian Wambeke,1965, p. 9-15) pyrochlore.The nameshould be dropped. Ba r i op y r oc hl o r e (name replaces pandaite, q.u. ) Chalcolamprile(Flink, 1898; 1901) contains a Yttropyrochlore (Kupriyanova, unpublished; de- "large numberof microscopicalinclusions" (Flink, scribed as obruchevite by Kupriyanova et al., 1964, 1901,p. 163)and apparentlyrepresents an impure anal.63) pyrochlore.The 10.86percent SiO, may be due to Ceriopyrochlore (name replaces marignacite, 4.u.) impurities.The nameshould be dropped. Plumbopyrochlore(Skorobogatova et al., 1966) Columbomicrolite(Yllliers, l94l) is an unnecessary Uranpyrochlore(Holmquist, 1896; name replaces synonym of pyrochlore.The name should be hatchettolite,q.u.) dropped. Djalmaite(Guimardes, 1939) is a synonymfor Speciesof the microlite subgroup uranmicrolite.The nameshould be dropped. Microlite (Shepard, 1835) Ellsworthite(Walker and Parsons,1923a) con- Stannomicrolite(name replacessukulaite, 4.u.) forms to the new definition of uranpyrochlore.The Bariomicrolite (name replaces rijkeboerite, q.u. ) nameshould be dropped. Plumbomicrolite(Hey, 1964,p. 1147;based on Sa- Endeiolite(Flink, l90l) is probablyan impurepy- fiannikoffand Van Wambeke, l96l) rochlore. The few tiny analysed crystals "were Bismutomicrolite (name replaces westgrenite, 4.u. ) scraped"from .The I L48 percentweight loss Uranmicrolite (Strunz, 1957; name replacesdjal- in HF and HrSOnwas assumed to be SiOr,essential maite, q.u.) to the compositionof the mineral.The nameshould be dropped. Speciesof the betafite subgroup Fluochlore(Hermann, 1850) is an earlysynonym of Yttobetafte (Kalita, I 959) pyrochlore,not used by later writers. The name Plumbobetafite(Ganzeev et al., 1969) shouldbe dropped. Betafite(Lacroix, 19l2b) Haddamite(Shepard, 1870) is assumedto be a synonymof microlite,but analysesare lacking.The Synonyms, doubtful and discredited names, and species nameshould be dropped. not belonging to the pyrochlore group Hatchettolite(Smith, 1877) is a synonym of The many synonyms and other names associated uranpyrochlore.Thename should be dropped. with the pyrochlore group are listed alphabetically Hydrochlore(Hermann, 1850) is an earlysynonym below, and discussedin light of the proposed no- of pyrochlore,not used by later writers. The name menclature. shouldbe dropped. Aluminobetafite (Kawai, 1960) may possibly be- Hydropyrochlore(lvanov et al., 1944)is probably long to the pyrochlore group and betafitesubgroup, an alteredmetamict pyrochlore. The nameshould be with unusual gross substitution of Al and some Sn dropped. and U. More data are needed. Koppite(Knop, 1875)is a poorlydefined variety of Azorpyruhite(Hubbard, 1886)probably belongsto pyrochlore.The type specimenis not available,but the pyrochloregroup, but as quantitativeanalyses are most specimensfrom the type locality arcpyrochlore lacking, the mineral cannot be classifiedor renamed (seeVan Wambeke,1964, p.67 for analyses).Jakob's at this time. analysis(Brandenberger, 1931) shows 9.73 percent Blomstrandile(Lindstrdm, 1874) has beenassumed Fe2O3,and contaminationis suspected.The name to belong to the pyrochlore group. It is possibly shouldbe dropped. uranpyrochlore, but adequate analyses are lacking, Marignacite(Weidmann and Lenher, 1907)is a and new data are desirable. synonym of ceriopyrochlore.The name should be Calciosamarskire(Ellsworth, 1928)has the compo- dropped. sition of uranian yttropyrochlore, but the mineral is Mendelyeeuiteor mendelejeuite(Vernadskii, 1914; metamict, and proof that it belongsto the pyrochlore 1923)is a synonymof betafite,the acceptedanalysis group is lacking. Van Wambeke (1970) suggeststhat (seeChukhrov and Bonshtedt-Kupletskaya,1967, p. a somewhat similar metamict mineral from Zaire 175-l'76,anal. 9) conformingto the redefinitionof may be yttrian uranpyrochlore with a high proportion this species,although the proportion of uraniumis of Fe3+in the B-positions.Further study seemsdesir- littleabove the necessary minimum. The name should able before deciding the statusof this mineral. be dropped. HOGARTH: THE PYROCHLORE GROUP

Metasimpsonile(Simpson, 1938, p. 88; Bowley, Samiresite(Lacroix, l9l2a) has the composition of 1939;Taylor, 1939,p. 93) is a synonymof miuolite. a plumbian uranpyrochlore(see Van Wambeke, 1970, The nameshould be dropped. p. 138).However, although this mineral is metamict, Mumbite(Van Wambeke,1970) is a synonymof apparently with octahedralhabit, it recrystallizeson plumbomicrolite.The name shouldbe dropped. heating (Gorzhevskaya et al., 1966; Gorzhevskaya Neotantalite(Termier, 1902) has long beenrecog- and Sidorenko, l97l) to a phase,"S", related to nizedas eithermicrolite or a closely-relatedmineral. synthetic UTarOro (Gasperin, 1965) and lesser The originalanalysis (by Pisani)showed Fe and Mn amounts of a pyrochlore phase.The name should be as the principal l-atoms and the absenceof Ca. dropped. Reexaminationof Termier'stype material by Gaspe- Scheteligite(Bjlrlykke, 1937)may possiblybelong in (1972\showed the mineralto bemetamict micro- to the betafite subgroup, with complex substitution lile with largedeficiencies in the l-ions, which may by Y, Mn, Sb, W, Bi, but more data are needed. be filled by Ba, Pb, U, and Ca. Fe and Mn were Silicate-wiikite (Strunz, 1957)must be discredited, presentas impurities.The nameshould be dropped. being a mixture; seewiikite. Niobpyrochlore(Machatschki, 1932) is an unneces- Stibiomicrolite(Quensel and Berggren,1938) must sary synonym for pyrochlore.The name should be be discredited, being a mixture of microlite, stibio- dropped. tantalile, andstibnite (see Ros6n and Westgren,1938) Niobtantalpyrochlore(Machatschki, 1932), imply- Sukulaite(Vorma and Siivola, 1967)is a synonym ing a compositionwith Nb ", Ta, must be renamed for stannomicrolite.The name should be dropped. eitherpyrochlore or microlite,according to the analy- Tangenite(Gagarin and Cuomo, 1949)was a name sis.The nameshould be dropped. presumptuously given to titanium-rich "betaftes" Nuolaite(Lokka, 1928),a mixture of yttropyro- from Norway (Tangenquarry near Kragerl). Two of chlore and other niobium mineralsrelates to the analysescorrespond ro betafte, and one to the wiikite(q.u.), must be discreditedas a species. titanian equivalent of pyrochlore. Recently W. L. Obrucheuite(Kalita, 1957)is a namelater shown to Griffin, of the Mineralogisk Museum, Oslo, has have beengiven to two differentspecies (Gorzhevs- shown that the specimens analyzed were mixtures kaya and Sidorenko,1969). One of these,brown (seetitanopyrochlore). The name is discredited. obruchevite,after heatingto 700oC,crystallized to Tantalbetafite(Kalita and Bykova, l96l) is a syn- the samiresile^l phase(4.u.). The other, black ob- onym for betafite.The name should be dropped. ruchevite,was subsequently renamed yttropyrochlore Tantalohatchettolite(Villiers, l94l) is a synonym (Kupriyanova, 1970, unpublished).The Soviet for uranmicrolite. The name should be dropped. Union's Commissionof New Minerals(KNM) and Tantalo-obrucheuite (van der Veen, 1963), in- MineralogicalTerminology have recommendedthe tended for the yttrium-rich member of the microlite nameyttropyrochlore replace this type of obrucheuite. group, has not been found. Pandaite(Jiiger et al., 1959)is a synonymfor Tantalpyrochlore (Machatschki, 1932) is a syn- bariopyrochlore.The name should be dropped. onym of microlite. The name should be dropped. Priazouite(Yurk, l94l1, 1956,p. 24), previously Titanbetafite (Ginzburg et al., 1960) is a synonym regardedas an alteredpyrochlore (Dzhun, 1963), has of betafite as redefined above. The name should be beenshown to belongto the samarskilegroup (Gor- dropped. zhevskayaand Sidorenko,1974) and must be ex- Titanmicrolite (Strunz, 1966, erroneously ascribed cludedfrom the pyrochloregroup. to van der Veen, 1963),with Ti ) Ta > Nb, has not Pyrochlore-microlite(Beus et al., 1962),implying a been found. compositionwith Nb ^, Ta must be renamedeither Titano-obrucheuite(van der Veen, 1963) is a syn- pyrochloreor microlite,according to the analysis. onym of yttrobetafite, and the name must be dis- Pyrochlore-wiikile(Strunz, 1957), being a mixture, carded. must be discredited;see wiikite, below. Titanopyrochlore (Machatschki, 1932) was named Pyrrhite (Rose, 1839,p. 5621'1842, p. 383-385) as a hypothetical titanian equivalent of pyrochlore. belongsto thepyrochlore group, but cannotbe classi- One of the analysesof Bjlrlykke(1931,anal.3), from fied becausethe type materialhas not beenanalyzed. the Tangen Quarry near Kragerf , Norway, conforms The nameshould be dropped. to a dominantly calcian member of the betafitesub- Rijkeboerite(van der Veen, 1963) is a synonymfor group. W. L. Griffin (correspondence,April 1974) bqriomicrolite.The name should be dropped. made a microprobe analysisof Bjlrlykke's specimen HOGARTH: THE PYROCHLORE GROUP

and found it to be composedof at leastfive different References phases. A "hatchettolite" from Hybla, Ontario Ant-Wuorinen,J. (1936)Der Wiikite und seine chemische Zusam- (Walker and Parsons,1923b, anal. l) approaches mensetzung.Bull. Comm.gbol. Finlande,ll5, 213-229. titanpyrochlorein bulk, but the material is in- Beus,A. A., andA. P. Kalita(1961) Recent data on theso-called homogeneous(Hogarth, unpublisheddata). The wiikite, Dokl. Akad. Nauk SSSR, /41, 705-708.(In Russian). nameshould be dropped. -, E. A. Severov,A. A. Sitninand K.'D. Subbotin(1962) greisenizedgranites (apogranites). Adad. Westgrenite(Knorring Mrose, 1963)is Albitized and Izoest. and a syn- lVazftS,SSR, Moscow. 194p. (In Russian). onym of bismutomicrolite.The name should be Bjdrlykke,H (1931)Ein Betafitmineralvon Tangenbei Kragerii. dropped. Norsk Geol.Tidsskr., 12,'13-88. IViikite(Ramsay, 1899, p. 379)and a- andB-wiik- - ( 1937)Mineral paragenesisof somegranite n€ar ile (Ant-Wuorinen, 1936) are mixtures of yttropy- Kragerl, southernNorway. Norsk Geol.Tidsskr., 17, l-16. py- rochlore pyrochloregroup Bonshtedt-Kupletskaya,E. M. (1966)Systematization of the or other membersof the rochlore-microlitemineral group. Zap. Vses.Mineral. Obsh- with euxeniteand silicates(Fauquier, 1960; Beus and chestua95, 134-144.(In Russian). Kalita, l96l) and must be discredited(see also pyro- Borodin,L. S., A. V. Bykova,T. A. Kapitonovaand Yu. A. chlore-wiikiteand silicate-wiikite). Pyatenko(1960) New data on zirconoliteand its niobian variety. Yttrohatchettolite(Kalita, 1959) has insufficient Dokl.Akad Nant SSSR.,134, ll88-l 19l. (In Russian). - and I. L Nazarenko(1957) Chemical composition of py- to be classifiedas uranpyrochlore.It is syn- rochloreand isomorphicreplacements in the ArBzXr molecule. onymous with yttropyrochlore.The name shouldbe Geokhimiya,No.4 [for 1957],2'18-295.(In Russianwith English dropped. summary). and niobozirconolitefrom U.S.S.R. andT. L. Richter(1956) The newmineral zircono- (Borodin et al., 1956;1960) are synonymouswith lite-a complexoxide of the ABrOt type. Dakl. Akad. Nauk (ln (Hussak and Prior, 1895),Parker and Flei- SSSR,1/0, 845-848. Russian). Bowley,H. (1939) (sp. nov.) from Tabba Tabba, West- scher(1968, p. 3l) havelisted niobozirconolite as a ern Australia.J. R. Soc. W. Aust. 25.89-92. member of the "pyrochlore-betafite-microliteBrandenberger,E. (1931)Die Kristallstrukturvon Koppit. Z. series,"but its monoclinicsymmetry excludes it from Kristallogr , 76, 322-334. the pyrochloregroup (Pudovkina et al., 1974). Chukrov, F. and E. M. Bonshtedt-Kupletskaya,Eds. (1967) Min- eraly,Yol 2, Pt. 3, Nauka Press,Moscow. (In Russian). Conclusions Dzhun, V, S. (1963)New data on the characteristicsofpriazovite. DopouidiAkad. Nauk URSR,10, 1379.1384.(In Ukranianwith The proposedscheme of classificationpermits the summariesin Russianand English). addition of new speciesto the group when data be- Ellsworth,H. V. (1928)A mineralrelated to samarskitefrom the comeavailable. In namingthese minerals, we recom- Woodcox Mine. Hybla, and from Parry Sound,Ontario. Am. mend a chemicalnomenclature, as outlinedabove. Mineral.. 13,63-68. Fauquier,D. (1960)Sur la "wiikite" et la "loranskite."C. R. Acad. The followingminerals or variantsare poorly de- Sci, 250. 3032-303.4. fined: aluminobetafite,azorpyrrhite, blomstrandite, Flink, G. (1898)Ber?ittelse om en mineralogiskresa i Syd-Gr6n- calciosamarskite,scheteligite. Type materialsshould land sommaren1897. Medd. Gry'nland, 14,221-262. be reinvestigated,and theirmineralogical status con- _ (lg0r) on the mineralsfrom Narsarsukon the Firth of firmed. Tunugdliarfik in southern Greenland. Medd. Grfnland, 24, 7- I 80. Gaertner,H. R. von (1930)Die Kristallstrukturenvon Loparit und Pyrochlor.Neues Jahrb. Mineral., Beil.-Band,6,f, Abt. A, Acknowledgments l-30. The Subcommitteegratefully acknowledges the help of Dr. Mi- Gagarin,G. andJ. R. Cuomo(1949) Algunas proposiciones sobre chaelFleischer, past-Chairman of the IMA Commissionof New nomencfaturamineralogica. Comun. insl. nac,inuest, cienc, nat, Mineralsand MineralNames, and ProfessorGlauco Gottardi, the del Museo Argentino Cienc. Natl. "Bernardino Riuadauia," presentsecretary of the Commission.Much assistancewas given Cienc.geol., /, No. 5, 2l p. by the All-Union MineralogicalSociety of the USSR,especially by Ganzeev,A. A., A. F. Efimov,and G. V. Lyubomilova(1969) ProfessorsV. A. Frank-Kamenetskii,Chairman of the Soviet Plumbobetafite,a new variety in the pyrochloregroup. Trudy Union'sCommission of New Mineralsand New MineralNames. Mineral.Muz. Akad. Nazk S,S.SR,19, 135-137.(In Russian). and E. K. Lazarenko,Chairman of the Commissionon Miner- Gasperin,M (1965)Synthdse et donn6escristallographiques d'un alogicalTerminology and Nomenclature.Dr. W. L. Griffin, Cura- oxyde double de tantaleet d'uranium. C. R. Acad. Sci.,261, tor of the MineralogiskMuseum, Oslo, kindly microprobedTan- 3417-3419. gen "titanpyrochlore."H. R. Steacy,of the GeologicalSurvey of - (1972\Contribution e I'Ctudede l'€tat m6tamicte:la "n6o- Canada,read the manuscriptand made valuable suggestions for its tantalite", une espEcediscr6dit6e. Bull. Soc.fr. Minbral. Cristal- improvement.Publication expenses were paid by a National Re- logr., 95, 451-457. searchCouncil of CanadaOperating Grant (A 2122)made to D. Ginzburg,A. I., S. A. Gorzhevskaya,E. A. Erofeevaand G. A. D. Hogarth. Sidorenko (1960) Titanium-tantalum-niobates.Geol. Mes- HOGARTH: THE PYROCHLORE GROUP 409

lorozhd. Redk. Elem. Nauchn.-Issled.Inst. Mineral. Syrya, 10. Levinson,A. A, (1966)A systemof nomenclaturefor rare-earth 168p. (In Russian). minerals.Am. Mineral.,J1, 152-158. Gorzhevskaya,S.A., G. P. Lugovskoiand G. A. Sidorenko( 1966) Lin, Teh-Sung,Wen-Hsing Hung and Tse-MinShih (1973) Cer- Siberian samiresite. Geol. Mestorozhd. Redk. Elem. Vses. uranopyrochlore-anew varietyof pyrochlore.Geochimica, l, Nauchn.-Issled.Inst. Mineral.Syrya, 30, 5l-71. (In Russian). 39-45.In Chinese). - and G. A. Sidorenko(1969) The obrucheviteproblem. LindstrdmG. (1874)Blomstrandit, ett nytt uranmineral frAn Nohl. TrudyMineral. Muz. Akad. r'r'aakSSSR, 19, 138-145.(In Rus- Geol.Fbren. Fbrh.,2. 162-164. sian). Lokka, L. (1928)Uber Wiikite. Bull. Comm.gbol. Finlande, 82, (1971)The structuraltype samiresite.Roentgenogr. 68 p. Mineral.Syrya, 8, 49-62.(In Russian). Machatschki,F. (1932)Die Pyrochlor-Romeit-Gruppe.Chem (1974) Productsof samarskitealteration. Trudy Erde.7. 56-76 Mineral.Muz. Akad. Nauk,SS.SR,23,72-77. (In Russian). Palache,C., H. Bermanand C. Frondel(1944') System of Mineh Guimardes,C. P. (1939)Djalmaita, um novomineral radioactivo. alogyof ... Dana,Tth ed.,Yol. l, JohnWiley and Sons,New AnnaesAcad. Brasil. Ci?ncias.I I . 347-350. York. Hermann,R. (1850)Untersuchungen iiber die ZusammensetzungParker,R. L. and M. Fleischer(1968) Geochemistry of niobium derTantalerze. J. Prakt.Chem..50.164-200. and tantalum.U.S. Geol.Sunt. Prof. Pap.,612. Hey, M. H. (1964)Twenty-third list of new mineralnames. Min- Pudovkina.Z. V., L. S. Dubakina,S. I Levedevaand Yu. A. eral. Mag., 33, 1125-1160. Pyatenko(1974) Study of Brazilianzirkelite. Zap. Vses.Min' Hogarth, D. D. (1961)A study of pyrochloreand betafrte.Can. eral.Obshch, 103,368-372. (In Russian). Mineral..6.610-633. Quensel,P. and T. Berggren(1938) Minerals of the Varutriisk Holmquist,P. J. (1896)Synthetische Studien iiber die Perowskit- .XI. The niobate-tantalategroup. Geol Fbren.Fdrh., und Pyrochlormineralien.Bull. Upsala Uniu., Inst., Geol.,3, 60. 2t6-225 l8l-266. Ramsay,W. (1899)A third list of new mineral names.Mineral. Hubbard,L. L. (1886)Ueber Azor-Pyrrhite und Zirkon von Laa- Mag.,13,363-381. cherSee sowie Pyrrhit und Azorit von SanMiguel. Verh.Natur- Rose,G. (1839)Beschreibung einiger neuen Mineralien des Urals. hist. Ver. preuss.Rheinland, Sitz.,43, 214-220. Pogg.Ann. Phys Chem.,48,551-572. Hussak,E. andG. T. Prior(1895) Lewisite and zirkelite, two new - (1842) Mineralogische-geognostischeReise nach dem Ural, Brazilianminerals. Mineral. Mag., I I, 80-88. dem Altai und dem KaspischenMeere, Yol. 2 Verlag Sand- Ivanov,A. A., I. B. Borovskiiand I. A. Yaroshch(1944) Pyro- erschenBuchhandlung, Berlin. chlore from the VishnevyeMountains, Urals. Zap. Vses.Min- Ros6n,O. andA. Westgren-(1938)On thestructure and composi- eral. Obshch.,73, 56-58.(In Russianwith Englishsummary). tion of mineralsbelonging to the pyrochlore-atopitegroup and J?iger,E., E. Niggli and A. H. van der Veen(1959) A hydrated an X-ray analysisof disintegratedstibiomicrolite. Geol. Fdren. barium-strontiumpyrochlore in a biotiterock from PandaHill, Fbrh.,60, 226-235. Tanganyika.Mineral. Mag., 32, 10-25. Safiannikoff.A. and L. Van Wambeke(1961) Sur une terme Kalita,A. P. (1957)Composition of obruchevite,a hydrated ura- plombifdredu groupepyrochlore-micrclite. Bull Soc.fr. Min- nium-yttrium varietyof pyrochlore.Dokl. Akad. Nau&,SSSR, bral. Cristallogr.,84, 382-384. ll7, l17-120.(In Russian). Shepard,C. U. (1835)Microlite, a new mineral species.Am. J. - (1959)New dataon someminerals in the AlakurttiVein Sci, 27, 361-362. No. l. Trudy Instit. Mineral. Geokhim. Kristallokhim. Redk. - (1870)Unknown mineral (microlite?) in Haddamcolum- Elem, 2, 164-l'12.(In Russian). bite.Am. J. sci.,50.93-94. - a1d A. V. Bykova(1961) Tantalum betafite from the La- Simpson,E. S. (1938)Annual Reportof the ChemicalBranch. doga pegmatites.Trudy Inst. Mineral. Geokhim.Kristallokhim. Rep.Dept Mines. l,V.Aust. for 1937,86-96. Redk.Elemen., 7 , 104-107. (In Russian). Skorobogatova,N. V., G. A. Sidorenko,K. A. Dorofeevaand Kawai,T. (1960)Chemical studies on mineralscontaining rare T. I. Stolyarova(1966) Plumbopyrochlore.Geol. Mestorozhd. elementsfrom the Far East:No. 54.Betafite from formerKaijo, Redk. Elem. Vses.Nauchn.-lssled. Inst. Mineral. Syrya,30, near Mukden, Manchuria. Nippon Kagaku Zasshi, 81, 84-95.(ln Russian). 1219-1220.(ln Japanese). Smith,J. L. (1977)Examination of theAmerican minerals, No. 6. Knop, A. (1875)Uber "Koppit" von Kaiserstuhl.Neues Jahrb. Am J. Sci..13.359-369. Mineral.,50, 66-69. Strunz, H. (1957)Mineralogische Tabellen, 3rd ed. Akademische Knorring,O. Von and M. E. Mrose(1963) Westgrenite and way- Verlagsgesellschaft,Leipzig, - (f Ver- landite,two new bismuthminerals from Uganda(abstr.). Geol. 966) MineralogischeTabellen,4th ed. Adademische Soc.Am. Spec.Pap., 73, 256-25'1. lagsgesellschaft,Leipzig. Kupryanova,l. I., M. I. VolkovaandZ. I. Goroshchenko(1964) Taylor, L. E. R, (1939)X-ray studiesof simpsonite.J. Roy. Soc. Rare earth mineralsin a molybdenitedeposit in the European W Aust.,25,93-97. U.S.S.R.Trudy Mineral. Muz. Akad. Narl

Lueshecarbonatite deposit (Kivu, RepublicofCongo). Eurotom (1923b)Hatchettolite and associated minerals from Rep,2l l0e,3l p. Hybla, Ontario. Uniu. TorontoStudies, Geol. Ser., 16,2l-24. - (1970) Alteration processesof some of the complex ti- Weidmann,S. and V. Lenher(1907) Marignacite, a newvariety of tano-niobo-tantalatesand their consequences.Neues Jahrb. pyrochlorefrom Wausau,Wisconsin. Am. J. Sci.,23, 287-292. Mineral.,Abh., I12. ll7-149. Wdhler,F. (1826)Ueber den Pyrochlor, eine neue Minelal Species. Vernadskii,V. I. (1914)Study of someradioactive mineral deposits Pogg.Ann. Phys.Chem.,7,417-428. of Russiaduring the summerof 1914.Bull. Acad.Imp. Sci.(6th Yurk, Yu. Yu (1941) Priazovite,a new mineral. Dopou.Akad. Ser.), 8, 1353-1384.(In Russian). Nauk URSR,3,15-22. (In Ukranian). Vernadsky,W. J. [Vernadskii,V. I.] (1923)La mendelejevite,- (1956) Redkie mineraly pegmatitou Priazouya. lzdatel. nouveaumin6ral radioactif. C. R. Acad. Sci.,176,993-994. Akad. Nauk URSR (Inst.Geol. Nauk), Kiev. 68 p. (In Rus- Villiers,J. E. de (1941)Columbomicrolite from Eshowe,Natal. sian). Am. Mineral.,26, 501-506. Zalashkova,N. E. and M. V. Kukharchik(1957) Bismuto-micro- Vorma,A. andJ. Siivola(1967) Sukulaite-TarSnrOr-and wodgi- lite-a new varietyof microlite.Trudy Inst. Mineral.Geokhim. nite as inclusionsin cassiteritein the granitepegmatite in Su- Kristallokhim.Redk. Elem. I,77-'19. (ln Russian). kula, Tammela,in S. W. Finland. Bull. Comm.gbol. Finlande, 229. 173-187. Walker, T. L., and A. L. Parsons(1923a\ Ellsworthite and asso- ciated mineralsfrom Hybla, Ontario. Uniu. TorontoStudies, Manuscript receiued, January 19, 1977: accepted Geol.Ser.. 16. 13-20. for publication, January 24, 1977.