UM1988-05-S:AgBiCuHgPb, Benjaminite, Cupropavonite

Inclusions to 5 mm of grey metallic Ag-(Hg)-Cu-Bi sulfosalts in Quartz matrix (overall 2.6 x 2.0 x 1.3 cm). Specimen collected by Gail Duning in the 1970s. This specimen was analyzed by SEM-EDX (CMEBA, Univ. Rennes), which revealed Benjaminite as the major component, associated to Cupropavonite and larges inclusions (up to 700 microns) of unidentified Bi-Pb-Hg-Ag-Cu phases. The semi-quantitative SEM-EDX results of the latter phases revealed variable compositions, related to the ones reported for “phase X” and “phase Y” by Foord et al (1988). The back-scattered electron (BSE) photographs show the unidentified Hg-bearing sulfosalt (light grey) with Benjaminite and Cupropavonite (darker). The first two pictures show a large inclusion of Hg-bearing sulfosalts, with variable composition as clearly evidenced by the different tones of grey.

For leading references on ore minerals of this complex locality and the new Ag-Hg-Cu-Bi sulfosalts, see: (a) Ford, E.E.; Shawe, D.R.; Conklin, N.M. “Coexisiting Galena, PbSss and Sulfosalts: Evidence for Multiple Episodes of Mineralization in the Round Mountain and Manharan Gold Districts. Nevada”, Canad. Miner. 1988, 26, 355-376. (b) Foord, E. E.; Shawe, D. R. “The Pb-Bi-Ag-Cu-(Hg) Chemistry of Galena and some Associated Sulfosalts: A Review and some New Data from Colorado, California and Pensylvania”, Canad. Miner. 1989, 27, 363-383. (c) Dunning, G.E., Moss, G.E. and Cooper, J.F. "The Outlaw mine Nye County Nevada." Miner. Rec., 1991, 22, 171-182.


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Photo added: 1st Nov 2009