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

R. Seetharam ¹

Affiliations
1 Petrologist, Mineral Exploration Corporation Ltd., Seminary Hills, Nagpur 440010, IN

Abstract

Gudmundite occurs as a common mineral constituent in the polymetallic ores of Askot. Three distinct modes of formation of gudmundite have been observed: (a) as a product of decomposition of tetrahedrite, (b) as a substitution product in cubanite and (c) as a reaction rim around breithauptite. The breakdown of tetrahedrite to chalcopyrite-gudmundite intergrowth signifies the retrograde metamorphism of this high temperature ore body. The eutectoid intergrowth between cubanite and gudmundite has resulted from a late stage hypogene replacement by addition of antimony.

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R. Seetharam ¹

Affiliations
1 Mineral Exploration Corporation Limited, Seminary Hills, Nagpur 440006, IN

Abstract

The sheared rhyolite-metasediment contact of the Tosham Hill is well-mineralised with disseminations and thin veins of very fine grained pyrite, pyrrhotite, chalcopyrite, sphalerite, galena, cassiterite, stannite, bismuthinite, rutile, hematite, wolframite and roquesite. Roquesite occurs intimately associated with chalcopyrite and is replacing it. The approximate reflectance of roquesite in white light measured in air was 20.7% and its average Vickers microhardness value was 229. Qualitative analysis of roquesite carried out with the help of the Laser microanalyser showed presence of major amounts of copper and indium and minor amount of silver. Based on the physical, optical and micro-chemical data, roquesite has been identified as the argentiferous variety, This is the first report of the occurrence of roquesite from India.

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R. Seetharam ¹

Affiliations
1 Mineral Exploration Corporation Ltd., Nagpur 440016, IN

Abstract

No Abstract.

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