Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

Kanika Basu ¹, N. Bortnykov ², A. Mookherjee ¹, N. Mozgova ²

Affiliations
1 Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur 721302, IN
2 Institute of Geology of Ore Deposits, USSR Academy of Sciences, Moscow 109017, RU

Abstract

Owyheeite is reported for the first time from an Indian ore deposit. Optical properties, microhardness and X-ray powder diffraction data of the mineral are furnished. Microprobe analysis yields the formula Pb_4.76(Ag_1.59CU_0.11)h_0.70Sb_6.54Sl_5.32. Comparison with other available microprobe data of samples from different localities indicates nonstoichiometric composition of the mineral phase. A small amount of copper seems necessary to stabilize the mineral, since it could not be synthesized in the system PbS-Ag₂S-Sb₂S₃. Curved nature of lamellar grains and existence of spindle-shaped deformation (?) twins imply pre- or syn-tectonic crystallization of the mineral.

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