American Mineralogist, Volume 67, pages 180-1E9, 1982 The mineralogy of pegmatites EorrBo sy GonooN E. BnowN. Jn. Department of Geology Staffird Univ e rsity, Stanford, California 94305 The Mineralogical Society of Anerica, in conjunction with che Friends of Mineralogyy held a eynpoeiuu on February 15-16r l98l in Tucson, Arizona, on the Mineralogy of Pegnatites. Gordon E. Brown, Jr. of Stanford Univereity served ae organizer and technical chairnan and Richard A. Bideaux of Bideaux Minerale, Tucaon, Arizone, gerved as local general chairmen. Ihe tt'o day progran, attended by over 150 nineralogiste, coneisted of 17 invit,ed or contributed PePersr which deecribed a variety of pegnatite localities in the U.S., Canada, South A.merica, Africa, and Ehe USSR, and aix papers on nore general subjecte ranging from Ehe origin of color in pegfiatite ninerale Eo iaotopic and experioental etudieg bearing on the paragenesia of pegnacites. In addition, Clifford Fondel of llarvard Univereicy preoented an infornative plenary lecture on the nineralogy and nining of early Anerican pegnetites. Of the lrrenly-three papere presenled, five were of a review nature and are listed by citle only. Abslrects of lhe other eighteen ere reprinted beLow. G.E. Brown, Jr. HINERILOGT OF THE BADU PECUATITE, LLANO COUNTY, TEXAS ElberE A. King, Department of Geology, Univeraity of Houaton, Houaton, Texas 77004 since the diecovery of lhe Badu pegnatite in 1935 by ilre. Tillie Badu uoss, the pegnacire hae been worked-interEittently 1" 9 eource of feidepar and, in r"-".r,t y".r", for decorative quertz. The nine is located aPProxiEately 4 nilee southueat of Buchanan Dan and 0.6 niles south of the ilano-Burnet highrray. Thia -location ia only 4.5 nilee s 35q{ fron the famoue Barringer Hill pegmacite, shich is now flooded and setl below lhe eurface elevation of Lake Buchanan. The eurface exposure of the Badu pegmatite is approxi- )roximately 35b feet wide. Ttre pegiatite ctriefiy con- hit.ic pink nicrocline, eone of which are rnore than 30 rtale. Minor ninerale in the Badu pegmatiEe include E€, sphene, anaEaae, fluorite, hematite, linonite, ats in the feldspar rnaeeee have produced aEtracEive which are deeply etched and contain fluid inclueione routheast ua11 of the present oine pit conEaine a )etailed exaninaEion of this area revealed ephene peeudouorpha, now moetly altered Eo anatase. The alteration of the ephene apparently was cauaed by a late stage fluorine-rich fluid which ceueed the production of the fluoriie-anatase-te.aiite aesembrage. Thig reaction can be degcribed by a ainple chenical equacion if che sphene ie assuned to contain ninor anounEs of irqr and hydroxyl. The najor poition of thig reaction hae been reproduced in the laboracory. PEGMATITES OF TnE ttAUsAU PLUTON, WISCONSTN AI FaIster, Al Falater Mioerals, Wauasu, I{ieconsin 5440I fire l{ausau Pluton, a largel eubvolcanic body of Precaobrian age, ie expoeed over an area of approxi- metely 360 equare km in_Marathorr County, wiscongin. It conaistg oi Liotite-tearing quartz eyenite-and is cut by nuueroue dikeg of pegnatite that are nost abundant in an outcrop area of auout b oquare km. some of theoe dikes are aa much ae 80 n long and E thick, but correeponding average dimensione for a1l the dikea probably are lees than 20 n and I n. About one-tiird of the pegnaiite boiiee contain irregular po"t"i", ranging in uexiuurn dimenaion fron lese than I cm co at least 4 or- that have yielded an unusual .rrii.ty oi uinerala. Nearly 50 epeciee have been identified Ehue far. The Eost abundant and wideepread pockec constituents are quartz, albite, nicrocline, muacovite, and clay uinerale. Surprisingly co@on to nany of the pockets are'aLmaniin", rn"t""., bertrandite, brooiite, chloriEe, columbite-tanleliter goethiter groeeular, henatite, ilmenite, lepidocrocite, opal, phenakite, pcilolelane, rutiler eiderite and xenocime. Leea comron nineiale, a few of then found in'only - one pockei to date, include anhydrite, ankerite, barite, bavenite, beryl, biotite, boulangerite,-pariei-te-aynchesite; calavlrite, cookeiEe, fluorice, galena, gold, janeaonite, . nanganocalcite, nicrolite, monazite, 9anidi19r aphaleriter. e'''biconiter etilpnonelanef tourmaline, and eeveral other species not yet identified. Thie rernarkable aeeemblage, which evidently representa a sy6tem wich unuaual concentrationa of Ber Nb-Ta, Sb, and Ti, hae provided excellent epecirnene and aone auperb nicro-naterial. The pegnatite occurrencea are not widely knownr but chey have yielded nany notevorthy crystale deepite ragher diificult collec ting conditione. 0003-004x/82/0102-0 l 80$02.00 180 BROWN: PEGMATITES lEl SOUEFAMOUS PEGI..IATITE LOCALITIES IN TTE U.S.S.R. Borie H. Shnakin, United Nations, New York, New York 10017 There are nunerous nineralogically diverse pegnaEiEe depoeite in the U.S.S'R.r aone of wtrich are of econooic importance. The localitiee reviewed Lelow are paet and present producere of nany of Ehe exceptionally fine nineral epecinena that appear in European and American nineralogical mueeuns. Trro iocereBting pegnatite regione are located within the Fenno-Scandinavian ehield srea Thoee locaEed on Ehe xeivy niage, Kola Penineula contain abundant amazonites of Ewo Predoninant colors: -griae-gtJ"n. greeniah-blue and Pegnatites located in northern Karelia are characterized by abundant ir"corrit., t'cergmic- mineialer" and red nicrocline and have a variety of acceea-ory,uinerale including uraninite. The Volynek pegoatitee, located wichin Ehe ltkrainian ehield, are asaociated with the Korosten (enoky granicic pluton. fn.y cotrtain niarolitic cavities filled nith large cryetale of norion quartz)r green beryll and rosy topaz. Two famoue pegnatite localigiee occur in the Ural6t (l) niarolitic pegnatites of the Mursinka-Aduy belt near Sverdlovgk containing beautiful cryetale of blue toPaz and heliodor beryl occurring on the ttcomb" Miaek wtrich aurface of a peculiar at-bite; and (2) iranitic pegrnatitee in the Ilnensk mounEaine near 6""onite and nuneroua REB-Nb-contairiog .""c""eory ninerals. The latter Pegoatites are located contain tthelvine", near nephelioe pegnatitee vtrich con.Eain abunlant cancrinite, eodalite, etc. Interes!ing touroaline-, beryl-, columbite-, caesicerite-bearing pegrnatites are located in the Turkestan Ridge area, Uziekian"poJ,5"rr"-, nepublic, ientral Aeia. In the Baikal region near Sludyanka and.in the 0lkhon region (Taiheran'St"pp" o., th; Nlf ehore of Baikal) there are pegmatitea containing amazonite and numerous REE in the accesssory ninerafs. Miarolite pegnatites occur at tranelaikalia (in the Adun-Chelon nountaine and Borgchovo'chny Ridge area along tie Snifta River) and conEain excellent crystalo of quartz, berylr topazt and varioua varietiee of tourmaline. The ilama peguaEite beltr located in the North Baikal Highland io rich (India) in muecovite and conprieee various genetic types Including analogues to the Bihar pegoatitee which bariuu contain t'ruby nica veing". Finally, th. iig-"otcaining pegoatites of the Aldan Shield contain orthoclaoe and nany accesaory minerale. ALPINE TYPE DERYL-EMERALDDEPOSITS NEAR IIIDDENITE, NORTITCAROLINA John Sinkankas, 5372 Van Nuye Courtr San Diegor California 92109 Occurrences of beryl and its chromium-bearing variety enerald in the vicinity of Hiddenite, Alexander County, North Carolina have been known gince I8]5. Several previoue atcenpts to e:(Ploit the dePositd for ninerii epecinene and gematones have net rrith only linited aucceos. Moet descriptione of Ehe dePosits c16ss them as pegnatites enclosed in the local biotite-gneies but field examinacions in 1969 thoeed that they are hydrotherual veine depoeited along a seriee of croes-cutEing fractured in the gneiea. In non:aaprolitized portione, wa11 alteration extenda to 6everal cn wiEh Ehe production of replacement roe"o.ri.te and albite with sone rutile. Within the veine, many of which are only parcly filled, quartz (nilky, amoky, late anethyatine), nuecovite, albite, goethite (ieeudonorphouo efter Fe-bearing carbonate), beryl- (aquanirine, late enerald) and rutile are comon epeciee. The morphology of the veins aa well aa the !'FundorEgruppe mineralization bear strong reseublancea Eo the Alpins klefts claseed as l0frt by If.A. Stalder, and others, in Die Mineralfunder der Schweiz (f973). Deepite the preeence of snall Pegnatile bodieeinterca1atedinttre@aPpearscobeconfinedtotheveingnentioned.For theae reasona, the veins are claesed ae Alpine in type and poasibly repreaent a unique node of emerald occurrence. Alchough no epodumene-bearing body was examined during the authorra vieit in 1969r it is algo likely chae the chroniurnj bearing epodumene (hiddenite) frorn thie diEtrict ie unique in ita oode of occurrence. BISXUTHIAN STIBIOCOLIN,TBITE-TANTA],ITEAND OTI1ERUINERALS FROU THE LITTLE THREE I{INE, RAMONA' CAIIFORNIA Eugene E. Foord, U.S. Geological Survey, Scop 905, Box 25046, Denver Federal Centerr Denverr Colorado EO225 Bienuthian etibiocolunbite-tantalite and other rare mineral apeciee occur in Ehe Pocket zone of Ehe niEh nain Little Three -pegnatite-aplire dike. The biauuthian 6tibiocolumbite-tantaliEe ie ageociated topaz, Iepidolile, tournaline (elbaite), cleavelandite, quartzr microcline, orthoclaser uicroliEe- rrannicrolite, and several aecondary mineral phasea: montmorilloniEe, pucheriter bisnutite, and cookeite. CryBtald of bianuthian stibiocolunbite-tantalite are euhedral, often doubly EerEinaEedr 0.01 m to 20 @ in parallel to b (vith or r.iirrr dimeneion, black, elongated along 111 eometioes flattened on ar and striated