728 NOTESAND NEWS Information supplied by the manufacturers of dimethyl sulfoxide statesthat toxicity doesnot seemto be a problem. Toxicologicalevalua- tion of preliminary animal studies reveais no sensitivity reactions or harmful effectson lung tissue.However, as thesestudies are continuing and the final word on this is yet to come,the manufacturersuggests that due careshould be exercisedin its handling and application. Rrlnnewcos Gnaconv, R. A., euo Srvr.r, D. W. G., 1936, The photo-oxidation of methylene iodide: Faraday Soe. Trans., 32, 7 30. Honcuex, C. D., 1957,Handbook of chemistry and physics, 39th ed.: Cleveland, Chemicai Rubber Publishing Co. Mnvnowrtz, R., Curnrre, F., ,tuo Hrcxr,rwc, N., 1959, A new diluent for bromoform in heavy liquid separation of minerals: Am Mineral.,44, 884-885. National Research Council, 1928, International critical tables of numerical data, physics, chemistry and technology, lst ed., v. 3: New York, McGraw-Hill Book Co., Inc. Truurnlrews, M. J., eNo HnNNaur-RouNo, Muo., 1932, Travaux du bureau interna- tional d'6talons physico-chimiques. V. Etude des constantes physiques de vingt com- pos6s organiques: Jonr. Clrimie Physique,29, 536. CAN MINERALOGIST, VOL. 45, MAY_JUNE, 1960 STIBIOTANTALITE FROM THE BROWN DERBY No. I PEGMATITE,COLORADO* E. Wu. HotNntcu, Departmenl of Mineralogy, The Uninersity of Michigan, Ann Arbor, M'ich'igan. The Brown Derby group of pegmatitesand especiallythe Brown Derby No. 1 pegmatite on the east side of Quartz Creek Valley in Gunnison County, Colorado,"are famous for the exceptionaldevelopment of the variety of pegmatitic mineralsthat they contain,ever sincethe discovery in them of lepidolite (Eckel, 1933).Minerals from this dike and its parent granite also have been used extensively for age determinations (e.g., Aldrich et al., 1956).The geologyof the dikes and of the district has been thoroughly investigated (Hanley et al., 1950; Staatz and Trites, 1955), and many of the minerals have been studied in detail: microlite (Eckel and Lovering, 1935);tourmalines (Staatz et al., 1955);columbite (Hein- rich and Giardini, 1957);garnet (Jaffe, 1951),the micas, especiallythe lepidolites(Heinrich etal.,19608); and monazite(Heinrich etal.,196OA). A list of the minerals identified with certaintv from the Brown Derbv group is given in Table 1. Stibiotantalitewas found by the writer in 1953in pegmatite blockson + Contribution from the Department of Mineralogy, The University of Michigan, Ann Arbor, Michigan, No. 237. NOTES AND NEWS 729 Tlsm 1. Mrlu:urs FRoM rHE Bnowx Dnrlv Gnoup on Pncuelrtns, Quenrz CnBan. GunNrsoN CouNrY, Cor,onnoo Magnetite Quartz Gahnite Microcline-perthite Hematite Oligoclase Columbite Albite (incl. cleavelandite) Microlite Beryl (greenish-blue and rose) Euxenite Topaz Stibiotantalite Garnet (yttrian spessartite) Tourmalines (pink, red, watermelon, Fluorite green, blue, purple, yellow, black) Muscovite Apatite Rose muscovite Monazite Sericite (incl. phengite) Lepidolites (1M, 6M) Zinnwaldite Biotite Chlorite the dumps from the main inclined workings in the Brown Derby No. 1 dike. The mineral, which is very rare, appears in relatively pure crystal fragments as large as 5X3+Y.2], cm. It is very likely that all of the pieces obtained came from a single cluster of crystals that was broken during mining. Occurring with the tantalum mineral are crystals of pink tour- maline as much as 1 cm. across. The stibiotantalite fragmentsare cut by thin veinletsof quartz and a colorlessmuscovite with 2V:Oo, probably a phengite. The tantalum mineral and its associateswere formed within albite-quartz-lepidolite rock of the lepidolite-quartz-cleavelanditeunit of Hanley et aI. (1950). Hamilton (1957), who also reports stibiotantalite from the Brown Derby, likewise notes pink tourmaline, quartz and Iepidolite as the asso- ciates.The identity of his material was verified by ProfessorC. S' Hurl- but of Harvard University. The optical and physicalproperties of the stibiotantalite are presented in Table 2, and.r-ray powder data are listed in Table 3. The chemical composition of the mineral is as iollows (semi-quantitative by way fluorescence): Ta:Or 48.8% NbzOs 8.6 SbzOa 42.6 BiuOr nil Pbo 0.06 RE nil The figure for Sbzoais by difference;the analysisshowed Sb to be the 730 NOTES AND NEWS Tl.pl-l. 2. Oprrcer, mm Pnvsrcnr Pnoppn:rrnsor rur Bnowx Dnnev SrrnrorANTAr,rrE Megascopic: Yellowish steel gray with a brilliant light yellowish resinous luster on fresh surfaces. tt:5.0; c:7.3. Cleavages:{010} good; {100} fair. Microscopic: Light brownish gray, highly translucent. Indices )2.00. T-d:0.08, (+), 2V:75., r(z strong. Slight alteration to opaque red brown isotropic material. In reflected light: light gray, anisotropism moderate. Strong yellow internal reflection. Exceedingly mi- nute specks of included galena (?) and pyrite (?). Minor alteration to medium gray material especially along fractures; alteration shows no internal reflection. only other major metallic element present in addition to Ta and Nb. Both U and Th are absent; an autoradiograph of 30 days exposure showedno darkening. The Brown Derby No. 1 pegmatite thus containsfor Nb-Ta minerals: columbite,euxenite, microlite, and stibiotantalite.Material termed beta- fite by Hanley et al,.(1950) has beenidentified as euxeniteby the writer. Other recorded United States occurrencesof stibiotantalite are at N{esaGrande, San Diego County, Caiifornia (Penfieldand Ford, 1906), and at Topsham, Maine (Palacheand Gonyer, 1940).In addition to the initial discovery at Greenbushes,wodgina district, western Australia Goyder, 1892), the mineral had also been found in the Varutrask, Sweden,pegmatite by Odman (1941).N[ore recently magnificentcrystals have been obtained from the Ribaue-Alto Ligonha pegmatite district, PortugueseEast Africa (especiallyfrom the Muiane pegmatite), includ- ing one brilliantly faced crystal weighing over 10 lbs., now in the U. S. National Museum (Bandy, 1951). Sosedko (1958) also has identified stibiotantalite crystals in a pegmatite in the northern part of the Kola Peninsula. RET,ERENCEs Ar.onrcn, L. T., G. L. Davrs, G R. Trr.roN, am G. W. WrrnEnrLL (1956). Iour. Geophys. Res,61. 215-232. Bar'nv, M C. (1951). Rochsand. Mi.nerols,26,512-521. Ecrrr., E. B. (1933). Jour. Amer. Ceram. ,Soc.,16,239-245. ero T. S. LovenrNc (193.5).Rpt. Comm. Meas. Geoi. Time, Natl. Res. Council, Exhibit V. Govonn, G. A. (1892). Proc. Chem. Soc.Lond.on,9, 184. HaurlroN, H V. (1957). Rochsand M'inerals,2S7,126. HaNr.nv, J. B., E Wu. Hnrnnrcrr, awo L. R. pacr (1950). U. S. Geol.Sunt. pro.f. paper 227. Hrrwnrcu, E. Wu., nxo A. A. GrnnlrNr (1957). Geot. Soc.Am. BuIt.,6g, 1744. NOTES AND NEWS 7sr Tasrn 3. X-nnv Pomnn DrtrnectroN Da.ra oN StrsrotA.NtAr'trt Cu Rlorlrrox, Ni Frr-rnt A B Stibiotantalite Stibiotantalite Mesa Grande,Calif. Brown Derby, Colo d(A) d(A) / <( w 3.52 3.5 m 3.12 VS 3.10 2.95 2.94 MS 2.78 2.70 m 2.68 mw z.Jl mw 2.45 w 2.05 1.99 vw 2.01 r.96 1.90 m 1.88 m 1.83 mw 1.84 w 1.81 mw 1.80 1.71 s f -/ J InS 1.72 1.708 r.667 t.662 mw 1.63 1.562 1.58 w 1.524 w 1..)J 1.52 150 r.49 vw 1.405 1.357 t.348 w 1.275 |.265 w r.24 1.23 1.19 1.183 l.t4 w 1.133 w 1.13 1.125 mw 1.087 1.o82 ---, A. A. LnvrNsou, ar.roR. A. Bonup (1960A). Geochinc-Cosmoehim"4clo (in press)' R. L. Cn.Lrc,eNo A. A. LevrNsoN (19608). Manuscript in preparation' Jasrn,H. W. (1951).Am. Mi.neral.,3L,122-t55. Oru,rN,O. H. (1941).Geol. Far. Fdrh.63,289-293. Par-ecnn.C.. ar*'oF. GoNvBn(1940). Am. Mineral.,25, 4ll-417. PeNrrrro, S. L., .LwoW. E. Foru (1906).Am. Jour. Sci ,22, 6l-77' Sosnrro, A. F. (1958).C. R. Acai|,.Scl. U.R.SS., r18' 1025-1026. Sreerz, M., aro A. F. Tnr:rns (1955) U' S' GeoI.Sura. ProJ. Poper 265' K. N. Mutnra, ANDJ. J. Grass (1955).Am- Mineral'.,40'789-804' .