gems, diamond, India, diamond mines

A geological and historical account by Valentine Ball of the diamond, gold and lead occurrences of the Sambalpur district in eastern India. Ball reviews earlier reports of diamond mining along the Mahanadi River and describes traditional washing methods in which river channels were diverted and gravels collected and washed for diamonds. He discusses the decline of organized diamond working under British rule and considers the probable geological source of the stones, relating them to rocks of the Vindhyan series. Ball also notes that the Mahanadi gravels yielded pebbles of beryl, topaz, carbuncle, amethyst, cornelian and rock crystal, while he had not seen ruby or sapphire from the district. The paper further treats local gold washing and lead ores, making it an important nineteenth-century source for the mineral resources and historical diamond workings of Sambalpur.