History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c13.s2.t3.1

v1.c13.s2.t3.1

Most probably the first Gold piece used for shaping into a simple ornament like spherical or cylindrical bead or a wire for making bangles was a small nugget but latter-on smelting and refining techniques were developed. Pure Gold melts at 1063°C which could be achieved easily in charcoal fire. The Gold sand obtained by panning was melted in a crucible and refined by the addition of fluxes like borax and a mixture of Ammonium Chloride, Borax and Ammonium nitrate in the ratio 6:1:3. The method of separation of Silver from Gold was known as ‘Niyaria’ and the craftsmen practicing the separation of Gold and Silver were known by this name. Even today about 300 families in Mirzapur are practicing this trade for separation of various metals like, Au, Ag, Cu, Ni, Zn, brass etc. from the dross obtained from parent metal industries.