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New structural data reveal benleonardite to be a member of the pearceite-polybasite group

  • Luca Bindi (a1), Christopher J. Stanley (a2) and Paul G. Spry (a3)


The determination of the crystal structure of benleonardite (P3m1; R = 0.0321 for 1250 reflections and 102 parameters; refined formula Ag15.00Cu1.00Sb1.58As0.42S7.03Te3.97) obtained using data from a gem-quality, untwinned crystal recovered from the type material, revealed that benleonardite exhibits the structure observed for minerals of the pearceite-polybasite group. The structure consists of the stacking of [Ag6(Sb,As)2S6Te]2– A and [Ag9Cu(S,Te)2Te2]2+ B layer modules in which (Sb, As) forms isolated SbS3 pyramids typically occurring in sulfosalts; Cu links two (S,Te) atoms with linear coordination, and Ag occupies sites with coordination geometries ranging from quasi-linear to almost triangular. The silver ions are found in the B layer module along two-dimensional diffusion paths and their electron densities are evidenced by means of a combination of a Gram-Charlier development of the atom displacement factors and a split model. In the structure, two S positions are completely replaced by Te (i.e. Te3 and Te4) and one is half occupied [S1: S0.514(9)Te0.486], whereas S2 is completely filled by sulfur. This distribution reflects the crystal-chemical environments of the different cations. On the basis of information gained from this characterization, the crystal-chemical formula of benleonardite was revised according to the structural results, yielding Ag15Cu(Sb,As)2S7Te4 (Z = 1) instead of Ag8(Sb,As)Te2S3(Z = 2) as previously reported. Thus, the mineral must be considered a member of the pearceite-polybasite group. A recalculation of the chemical data listed in the scientific literature for benleonardite according to the structural results obtained here leads to excellent agreement.


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Aksenov, VS., Gavrilina, K.S., Litvinovich, A.N., Bespaev, K.H.A., Pronin, A.P., Kosyak, E.A. and Slyasarev, A.P. (1969) Occurrence of new minerals of silver and tellurium in ores of the Zyranov deposits in the Altai (in Russian). Altai Izvestiya Akademiya Nauk Kazakh SSR, Seriya Geologicheskaya, 3, 7478.
Bindi, L. and Evain, M. (2007) Gram-Charlier development of the atomic displacement factors into mineral structures: The case of samsonite, Ag4MnSb2S6 . American Mineralogist, 92, 886891.
Bindi, L., Evain, M. and Menchetti, S. (2006a) Temperature dependence of the silver distribution in the crystal structure of natural pearceite, (Ag,Cu)i6(As,Sb)2Sn. Ada Crystallographica, B62, 212219.
Bindi, L., Evain, M, Pradel, A., Albert, S., Ribes, M. and Menchetti, S. (20066) 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, 677690.
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, 918925.
Bindi, L., Evain, M. and Menchetti, S. (20076) Complex twinning, polytypism and disorder phenomena in the crystal structures of antimonpearceite and arsenpolybasite. The Canadian Mineralogist, 45, 321333.
Bindi, L., Evain, M., Spry, P.G., Tait, K.T and Menchetti, S. (2007c) Structural role of copper in the minerals of the pearceite-polybasite group: The case of the new minerals cupropearceite and cupropolybasite. Mineralogical Magazine, 71, 641650.
Bindi, L., Evain, M. and Menchetti, S. (2007) Selenopolybasite, [(Ag,Cu)6(Sb,As)2(S,Se)7] [Ag9Cu (S,Se)2Se2], a new member of the pearceite-polybasite group from the De Lamar Mine, Owyhee county, Idaho, USA. The Canadian Mineralogist, 45, 15251528.
Bindi, L. and Menchetti, S. (2009) Adding further complexity to the polybasite structure: The role of silver in the B layer of the M2a2b2c polytype. American Mineralogist, 94, 151155.
Bindi, L., Voudouris, P. and Spry, P.G. (2013) Structural role of tellurium in the minerals of the pearceite-polybasite group. Mineralogical Magazine, 77, 41928.
Boucher, E, Evain, M. and Brec, R. (1993) Distribution and ionic diffusion path of silver in y-Ag8GeTe6: A temperature dependent anharmonic single crystal structure study. Journal of Solid State Chemistry, 107, 332346.
Downs, R.T., Bartelmehs, K.L., Gibbs, G.Y and Boisen, M.B. Jr. (1993) Interactive software for calculating and displaying X-ray or neutron powder diffractometer patterns of crystalline materials. American Mineralogist, IS, 1104-1107.
Evain, M, Bindi, L. and Menchetti, S. (2006a) Structural complexity in minerals: twinning, polytypism and disorder in the crystal structure of polybasite, (Ag,Cu)16(Sb,As)2Sn. Ada Crystallographica, B62, 447456.
Evain, M, Bindi, L. and Menchetti, S. (20066) Structure and phase transition in the Se-rich variety of antimonpearceite,[(Ag,Cu)6(Sb,As)2(S,Se)7][Ag9Cu (S,Se)2Se2]. Ada Crystallographica, B62, 768774.
Helmy, H.M., Kamel, O.A. and El Mahallawi, M.M. (1999) Silver and silver-bearing minerals from the Precambrian volcanogenic massive sulfide deposit, Um Samiuki, Eastern Desert, Egypt. Pp. 163-166 in: Mineral Deposits: Processes to Processing (Stanley, C.J. et al, editors) Balkema, Rotterdam.
Herrington, R.J., Maslennikov, YY, Stanley, CJ. and Buslaev, F. (1998) Tellurium-bearing phases in black smoker chimney fragments from the Silurian Yaman Kasy massive sulphide orebody, southern Urals, Russia. Abstracts and Programme, 17th General Meeting of the International Mineralogical Association Toronto, Canada, A119.
Johnson, C.K. and Levy, H.A. (\914) International Tables for X-ray Crystallography Vol. IV﹛1. A. Ibers and Hamilton, W.C. , editors). Pp. 311-336. Kynoch Press, Birmingham, UK
Karup-Moller, S. and Pauly, S. (1979) Galena and associated ore minerals from the cryolite at Ivigtut S. Greenland. Meddelelser om Gronland Geoscience, 2, 125.
Kuhs, W.F. (1984) Site-symmetry restrictions on thermal-motion-tensor coefficients up to rank 8. Ada Crystallographica, A40, 133137.
Moelo, Y, Makovicky, E., Mozgova, N.N., Jambor, J.L., Cook, N., Pring, A., Paar, W.H., Nickel, E.H., Graeser, S., Karup-Moller, S., Balic Zunic, T., Mumme, W.G., Vurro, F., Topa, D., Bindi, L., Bente, K. and Shimizu, M. (2008) Sulfosalt systematics: a review. Report of the sulfosalt sub-committee of the IMA Commission on Ore Mineralogy. European Journal of Mineralogy, 20, 746.
Oxford Diffraction (2006) CrysAlis RED (Version and ABSPACK in CrysAlis RED. Oxford Diffraction Ltd, Abingdon, Oxfordshire, England.
Pals, D.W. and Spry, PG. (2003) Telluride mineralogy of the low-sulfidation epithermal Emperor gold deposit, Vatukoula, Fiji. Mineralogy and Petrology, 79, 285307.
Petficek, Y, Dusek, M. and Palatinus, L. (2006) JANA2006, a Crystallographic Computing System. Institute of Physics, Academy of Sciences of the Czech Republic, Prague.
Spry, PG. and Thieben, S.E. (1996) Two new occurrences of benleonardite, a rare silver—tellurium sulphosalt, and a possible new occurrence of cervelleite. Mineralogical Magazine, 60, 871876
Stanley, C.J., Criddle, A.J. and Chisholm, J.E. (1986) Benleonardite, a new mineral from the Bambolla mine, Moctezuma, Sonora, Mexico. Mineralogical Magazine, 50, 681686.
Williams, S.A. (1982) Cuzticite and eztlite, two new tellurium minerals from Moctezuma, Mexico. Mineralogical Magazine, 46, 257259.
Zhang, X. and Spry, PG. (1994) Petrological, mineral-ogical, fluid inclusion, and stable isotope studies of the Gies gold—silver telluride deposit, Judith Mountains, Montana. Economic Geology, 89, 602627.


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