History of Technology in India, Vol. I: From Antiquity to c. 1200 A.D. v1.c14.s3.17

v1.c14.s3.17

Several coins, scrutinised under microscope, show homogeneity or near-homogeneity in size of the grains of their metal.¹⁴ This indicates that even if the coin was cold worked, the cast metal of the blank was heated and worked out (as indicated above). Or we may presume that a cold worked coin was heated to a high temperature to remove the strain sustained by its metal at the time of striking. At the time of heat treatment a good amount of recrystallisation could have taken place making the metal quite homogenized from the point of view of size of its grains. The same effect could have been achieved by striking the blank at a high temperature. But the hot-working could have affected the die-life.