gems, India, copper

Newbold surveys copper occurrences in the Ceded Districts, South Mahratta country and Nellore, emphasizing the Nellore mines examined during January 1840. He describes copper carbonates and sulphides in quartz veins, gneiss and crystalline schists, recording individual workings, associated minerals and published ore analyses. Field relationships lead him to dispute the interpretation that the copper mineralization formed simultaneously with its enclosing rocks. Of gemological interest are garnets, including crystals resembling hessonite, white and rose-colored quartz, tourmaline and kyanite; he also suggests using granular garnet rock as a substitute for emery in polishing gemstones. His economic assessment weighs ore richness against drainage difficulties, fuel and timber supplies, labor and transport. Historical workings and slag heaps provide evidence of earlier mining and effective metal extraction, while renewed operations demonstrate both the district’s potential and the practical obstacles to profitable development.