Studies on the composition of ancient Indian punch-marked silver coins

Punch-marked coins are the oldest known numismatic objects used in ancient India. Seven punch-marked silver coins were analysed by using the non-destructive multi-elemental PIXE technique. A 3 MeV proton beam from a pelletron accelerator was used for irradiation of these samples to obtain the spectral data and GUPIX software was employed to derive the elemental concentrations. The results reveals that silver, copper, gold and lead are significant constituents of the punch-marked silver coins and there are also traces of elements such as Ti, Cr, Mn, Fe, Co, Ni, As and Y, which seems to imply that PIXE can be used effectively for the non-destructive quantitative analysis of ancient coins. Copyright © 2004 John Wiley & Sons, Ltd.