Minerals and Metals in Ancient India v1.c18.11

v1.c18.11

Like gold and silver, copper also occurs in the metallic state in nature, and it is possible that native copper was used first in human civilization prior to the discovery of the art of smelting the metal from its oxide, carbonate and sulphide minerals. Native copper could be used to manufacture artefacts by one of the three ways: cold hammering, periodic annealing using heat and by melting and solidification which changes the grain orientation.