Minerals and Metals in Ancient India v2.c41.s7.3

v2.c41.s7.3

The purity of the raw-materials — gold and silver ore, scrap and ornaments for re-use — had to be checked through streak tests on special touchstones (2.13.17-25) and chemical tests such as whitening of gold by vermilion or iron sulphate (2.13.19).