History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c13.s2.t3.2

v1.c13.s2.t3.2

The purified metal bar or ingot was worked by forging, punching, embossing etc. for the production of various ornaments having intricate designs. Even rolling and wire drawing was known to the ancient craftmen. Gold coins were either made by die casting in clay moulds or by the technique of punch marking and the quality of the metal was judged with the help of ‘Touch Stone’ and coin’s weight was accurately measured. *Arthaśāstra* of Kauṭilya gives detailed account of the knowledge of minting of coins and production of other objects and the technology of gem setting. They had also learnt to produce Au-Ag and Au-Cu alloys and the use of gold solder (Au:Ag, 8:1) and the ways to improve the golden colour finishing of the joints as early as the vedic period. Today it is well known that Au-Ag have a Eutectic type phase diagram whereas Au-Cu have complete solid solubility and alloying with these metals impart strength, hardness and various shades of colours to the metal as well as lower the melting point of the alloy. As mentioned earlier the technique of Hg amalgamation and gilding was also known to the Indian craftmen from the very early times.