Copper in Ancient India c10.s3.4

c10.s3.4

In India, zinc appears to have been extracted from calamine (Sanskrit "rasaka" or "kharpara") by heating it in a covered crucible with substances rich in carbon at least as early as the 7th century. We find the description of a process of the extraction of "essence of calamine" in the alchemical work of the 7th century named Rasaratnākar, ascribed to Nāgārjuna which gives the following recipe—calamine is macerated, amongst other things, with carbonated alkali lac, soot and borax and then heated in a covered crucible in a furnace when an essence of the colour of tin is obtained.¹