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Oscarkempffite, Ag10Pb4(Sb17Bi9) 26S48, a new Sb-Bi member of the lillianite homologous series

Published online by Cambridge University Press:  02 January 2018

Dan Topa*
Affiliation:
Natural History Museum-Vienna, Burgring 7, A-1010 Vienna, Austria
Werner H. Paar
Affiliation:
A-5020 Salzburg, Pezoltgasse 46, Austria
Emil Makovicky
Affiliation:
Department of Geoscience and Resource Management, University of Copenhagen, Østervoldgade 10, DK-1350, Copenhagen K, Denmark
Chris J. Stanley
Affiliation:
The Natural History Museum, Cromwell Road, London SW7 5BD, England, UK
Andy C. Roberts
Affiliation:
Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A OE8, Canada

Abstract

Oscarkempffite, ideally Ag10Pb4(Sb17Bi9)∑=26S48, is a new mineral species found in old material (1929–30) from the Colorada vein, Animas mine, Chocaya Province, Department of Potosi, Bolivia. It is associated with aramayoite, stannite, miargyrite, pyrargyrite and tetrahedrite. Oscarkempffite forms anhedral grains and grain aggregates up to 10 mm across. The mineral is opaque, greyish black with a metallic lustre; it is brittle without any discernible cleavage. In reflected light oscarkempffite is greyish white, pleochroism is distinct, white to dark grey. Internal reflections are absent. In crossed polars, anisotropism is distinct with rotation tints in shades of grey. The reflectance data (%, air) are: 39.9, 42.6 at 470 nm, 38.6, 41.7 at 546 nm, 38.1, 41.2 at 589 nm and 37.3, 40.6 at 650 nm. Mohs hardness is 3–3½, microhardness VHN50 exhibits a range 189–208, with a mean value 200 kg mm–2. The average results of four electron-microprobe analyses in a grain are: Cu 0.24(7), Ag 14.50(8), Pb 11.16(14), Sb 28.72(16), Bi 24.56(17), S 20.87(5), total 100.05(6) wt.%, corresponding to Cu0.24Ag9.92Pb4.00Sb17.36Bi8.64S47.84 (on the basis of Me + S = 88 apfu). The simplified formula, Ag10Pb4Sb17Bi9S48, is in accordance with the results of a crystal-structure determination. The density, 5.8 g cm–3, was calculated using the ideal formula. Oscarkempffite has an orthorhombic cell with a = 13.199(2), b = 19.332(3), c = 8.249(1) Å, V = 2116.3(5) Å3, space group Pnca and Z = 1. The strongest eight lines in the (calculated) powder-diffraction pattern are [d in Å(I)hkl]: 3.66(35)(122), 3.37(70)(132), 3.34(100)(250), 2.982(55)(312), 2.881(86)(322), 2.733(29)(332), 2.073(27)(004) and 2.062(31)(182). Comparison with gustavite, andorite and roshchinite confirms its independence as a mineral species.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2016

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References

Ahlfeld, F. and Reyes, J.M. (1938) Mineralogie von Bolivien. Gebrüder Borntraeger, Berlin, 90pp.Google Scholar
Ahlfeld, F. and Schneider-Scherbina, A. (1964) Los yacimientos minerales y de hidrocarburos de Bolivia. Boletín de Departamento Nacional de Geología del Ministerio de Minas y Petroléo, 5, 388 pp.Google Scholar
Hellner, E. (1958) A structural scheme for sulfide minerals. Journal of Geology, 66, 503525.CrossRefGoogle Scholar
Kraus, W. and Nolze, G. (1999) PowderCell 2.3. Federal Institute for Materials Research and Testing, Berlin, Germany.Google Scholar
Makovicky, E. and Karup-Møller, S. (1977a) Chemistry and crystallography of the lillianite homologous series. Part 1. General properties and definitions. Neues Jahrbuch für Mineralogie, Abhandlugen, 130, 264—287.Google Scholar
Makovicky, E. and Karup-Møller, S. (1977b) Chemistry and crystallography of the lillianite homologous series. Part 2. Definition of new minerals: eskimoite, vikingite, ourayite and treasurite. Redefinition of schirmerite and new data on the lillianite-gustavite solid-solution series. Neues Jahrbuch für Mineralogie, Abhandlugen, 131, 56—82.Google Scholar
Makovicky, E. and Topa, D. (2011) The crystal structure of gustavite, PbAgBi3S6. Analysis of twinning and polytypism using the OD approach. European Journal of Mineralogy, 23, 537550.CrossRefGoogle Scholar
Makovicky, E. and Topa, D. (2014) Lillianites and andorites: new life for the oldest homologous series of sulfosalts. Mineralogical Magazine, 78, 387414.CrossRefGoogle Scholar
Moëlo, Y., Makovicky, E. and Karup-Møller, S. (1989) Sulfures complexes plombo argentiferes: minéralogie et cristallochimie de la série andorite—fizélyite, (Pb, Mn,Fe,Cd,Sn)3_2x(Ag,Cu)x(Sb,Bi,As)2+x(S,Se)6. Documents du BRGM, 167, 1107.Google Scholar
Mozgova, N.N., Nenasheva, S.N., Borodaev, Y.S., Sivstov, A.V., Ryabeva, E.G. and Gamayanin, G.N. (1987) New mineral varieties in sulphosalts group. Zapiski Vsesoyuznogo Mineralogicheskogo Obshchestva, 116, 614–28.[in Russian].Google Scholar
Pažout, R. and Dušek, M. (2009) Natural monoclinic AgPb(Bi2Sb)3S6, an Sb-rich gustavite. Acta Crystallographica, C65(11), 177180.Google Scholar
Pažout, R. and Dušek, M. (2010) Crystal structure of natural orthorhombic Ag0 71Pb! 52Bi! 32Sb! 45S6, a lillianite homologue with N = 4; comparison with gustavite. European Journal of Mineralogy 22, 741—750.Google Scholar
Petrova, I.V., Pobedimskaya, E.A. and Spiridonov, E.M. (1986) Crystal structure of roshchinite.Materialy X. Vsesoyuz. Sov. po Rentgenografii Mineral'nogo Syrya, Tbilisi, 99100.[in Russian].Google Scholar
Sawada, H., Kawada, I., Hellner, E. and Tokonami, M. (1987) The crystal structure of senandorite (andorite VI): PbAgSb3S6.ZeitschriftfürKristallographie, 180, 141150.Google Scholar
Spencer, L.J. and Mountain, E.D. (1926) Aramayoite, a new mineral from Bolivia. Mineralogical Magazine, 21, 156162.CrossRefGoogle Scholar
Spiridonov, E.M., Petrova, I.V., Dashevskaya, D.M., Balashov, E.P. and Klimova, L.M. (1990) Roshchinite, Pb10Ag19Sb51S96 - a new mineral. Doklady Akademii Nauk SSSR, 312, 197200.Google Scholar
Topa, D., Makovicky, E., Paar, W.H., Stanley, C.J. and Roberts, A.C. (2011) Oscarkempffite, IMA 2011–029. CNMNC Newsletter No. 10, October 2011, page 2607; Mineralogical Magazine, 75, 26012613.Google Scholar