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Structural role of copper in the minerals of the pearceite-polybasite group: the case of the new minerals cupropearceite and cupropolybasite

Published online by Cambridge University Press:  05 July 2018

L. Bindi*
Affiliation:
Museo di Storia Naturale, sezione di Mineralogia, Università degli Studi di Firenze, Via La Pira, 4, I-50121, Firenze, Italy
M. Evain
Affiliation:
Laboratoire de Chimie des Solides, I.M.N., UMR 6502 CNRS - Université de Nantes, 2 rue de la Houssinière, B.P. 32229, F-44322 Nantes Cedex 3, France
P. G. Spry
Affiliation:
Department of Geological and Atmospheric Sciences, 253 Science I, Iowa State University, Ames, Iowa 50011- 3212, USA
K. T. Tait
Affiliation:
Department of Natural History, Royal Ontario Museum, 100 Queens Park, Toronto, Ontario M5S 2C6, Canada
S. Menchetti
Affiliation:
Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Via La Pira, 4, I-50121, Firenze, Italy

Abstract

The pearceite-polybasite group of minerals, general formula [M6T2S7][Ag9CuS4] with M = Ag, Cu; and T = As, Sb, show a crystal structure which can be described as the succession, along the c axis, of two pseudo-layer modules: a [M6T2S7]2–A module layer and a [Ag9CuS4]2+B module layer. Copper is present in one structural position of the B module layer and replaces Ag in the only fully occupied M position of the A module layer. When the Cu content is >4.00 a.p.f.u., the structural position of the A module layer becomes Cu-dominant and, consequently, the mineral deserves its own name. In this paper we report the crystal-chemical characterization of two Cu-rich members exhibiting the 111 unitcell type (corresponding to the Tac polytype). One sample (space group (P)m1, a 7.3218(8), c 11.8877(13) Å, V 551.90(10) Å3, Z = 1) having As >Sb and with the structural position of the A module layer dominated by Cu, has been named cupropearceite and the other sample (space group (P3̄)m1, a 7.3277(3), c 11.7752(6) Å, V 547.56(8) Å3, Z = 1) having Sb >As has been named cupropolybasite.

Both the new minerals and mineral names have been approved by the IMA-CNMNC.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2007

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References

Becker, P.J. and Coppens, P. (1974) Extinction within the limit of validity of the Darwin transfer equations. I. General formalism for primary and secondary extinction and their applications to spherical crystals. Acta Crystallographica, A30, 129–147.Google Scholar
Bindi, L., Evain, M. and Menchetti, S. (2006a) Temperature dependence of the silver distribution in the crystal structure of natural pearceite, (Ag, Cu)16(As, Sb)2S11 . Acta Crystallographica, B62, 212–219.Google Scholar
Bindi, L., Evain, M., Pradel, A., Albert, S., Ribes, M. and Menchetti, S. (2006b) Fast ionic conduction character and ionic phase–transitions in disordered crystals: The complex case of the minerals of the pearceite–polybasite group. Physics and Chemistry of Minerals, 33, 677–690.CrossRefGoogle Scholar
Bindi, L., Evain, M., Spry, P.G. and Menchetti, S. (2007a) The pearceite–polybasite group of minerals: Crystal chemistry and new nomenclature rules. American Mineralogist, 92, 918–925.CrossRefGoogle Scholar
Bindi, L., Evain, M. and Menchetti, S. (2007b) Selenopolybasite, [(Ag, Cu)6(Sb, As)2(S, Se)7] [Ag9Cu(S, Se)2Se2], a new member of the pearceitepolybasite group from the De Lamar Mine, Owyhee County, Idaho, USA. The Canadian Mineralogist, 45, 1525–1528.CrossRefGoogle Scholar
Bindi, L., Evain, M. and Menchetti, S. (2007c) Complex twinning, polytypism and disorder phenomena in the crystal structures of antimonpearceite and arsenpolybasite. The Canadian Mineralogist, 45, 321–333.CrossRefGoogle Scholar
Burton, W.D. (1926) Ore deposition at Premier Mine, B.C. Economic Geology, 21, 586–604.CrossRefGoogle Scholar
Chuguevskaya, O.M. (1969) The genetic features of the Sarbay and Yrltai magnetite deposits in Turgai. Geology and Mineralogy Nauk, Alma Ata, Kazakhstan (in Russian).Google Scholar
Dymkin, A.M. (1966) The Petrology and Origin of the Magnetite Deposits of Turgai. Nauka Press, Novisibirsk, Russia (in Russian).Google Scholar
Evain, M., Bindi, L. and Menchetti, S. (2006) Structural complexity in minerals: twinning, polytypism and disorder in the crystal structure of polybasite, (Ag, Cu)16(Sb, As)2S11 . Acta Crystallographica, B62, 447–456.Google Scholar
Johnson, C.K. and Levy, H.A. (1974) International Tables for X–ray Crystallography (Ibers, A. and Hamilton, W.C., editors). Vol. 4, 311–336 pp. Kynoch Press, Birmingham, UK.Google Scholar
Kuhs, W.F. (1984) Site–symmetry restrictions on thermal–motion–tensor coefficients up to rank 8. Acta Crystallographica, A40, 133–137.Google Scholar
Makovicky, E. and Skinner, B.J. (1979) Studies of sulfosalts of copper VII. Crystal structures of the exsolution products Cu12.3Sb4S13 and Cu13.8Sb4S13 of unsubstituted synthetic tetrahedrite. The Canadian Mineralogist, 17, 619–634.Google Scholar
Oxford Diffraction (2006) CrysAlis RED (Version 1.171.31.2) and ABSPACK in CrysAlis RED. Oxford Diffraction Ltd, Abingdon, Oxfordshire, U.K. Google Scholar
Panteleyev, A. (1991) Gold in the Canadian Cordillera – A focus on epithermal and deeper environments. In: Ore Deposits, Tectonics and Metallogeny in the Canadian Cordillera. British Columbia Ministry of Energy, Mines and Petroleum Resources paper 1991–1994.Google Scholar
Pekov, I.V. and Karpenko, V.Yu. (1997) Minerals of the silver–bearing veins of the Sarbay deposit (North Kazakhstan). World of Stones, 12, 2–15.Google Scholar
Petříček, V., Duek, M. and Palatinus, L. (2000). JANA 2000, a Crystallographic Computing System. Institute of Physics, Academy of Sciences of the Czech Republic, Prague.Google Scholar
Petruk, W., Harris, D.C., Cabri, L.J. and Stewart, J.M. (1971) Characteristics of the silver–antimony minerals. The Canadian Mineralogist, 11, 198–231.Google Scholar
Pfitzner, A., Evain, M. and Petříček, V. (1997) Cu12Sb4S13: A temperature–dependent structure investigation. Acta Crystallographica, B53, 337–345.Google Scholar