Occurrence of Gem Variety Green Sphalerite and Dyscrasite in Rocks of the Aravalli Supergroup, India

The Zawar Belt in Udaipur district, Rajasthan (Figure 1), the host of polymetallic assemblage of Pb, Zn, Ag, Cd has a history of mining and smelting for zinc going back to 2100 years old^1–3. Recently, green coloured gem variety of sphalerite has been found in Zawar mine associated with galena and dyscrasite (Ag₃Sb). This variety is different from the conventionally mined ore mineral of Zn which is mainly brown and honey brown in colour. This is the first report of green sphalerite from India. Previously it has been reported from Madan Orefield, Bulgaria⁴. The major rock types in Zawar Belt are arkosic quartzite, greywacke, phyllite, carbonaceous phyllite and dolomite of the Aravalli Supergroup of the Palaeoproterozoic age. The Pb–Zn mineralization is mainly confined to the dolomite of Baroi Magra Formation, Udaipur Group, Aravalli Supergroup.