Major and Trace Elements in Sasanian Silver

Abstract

Thermal neutron activation analysis was done on small samples from Sasanian silver objects to determine the concentrations of three major elements, Ag, Cu, and Au, and 18 trace elements, Na, K, Sc, Cr, Mn, Fe, Ni, Co, Zn, As, Br, Sn, Sb, Se, Ir, and Hg. Two microsampling techniques (drilling and rubbing) were used for Ag, Cu, and Au. Analyses for major components in rubbing and drilling samples of the same objects showed the effects of surface enrichment for gold and surface depletion of copper. Drilled samples of ca. 500 micrograms were used to determine trace element concentrations. Multiple analyses were satisfactorily reproducible in the silver alloy for Ir, Zn, Se, As, and Sb, less satisfactory for Sn, Sc, Mn, and Br while large inhomogeneities were observed for Cr, Ni, Fe, Co, Hg, Na, and K. We attempted to group objects according to trace element compositions and to relate such groups to art historical information. So far, gold and iridium concentrations seem to be the most promising criteria for distinguishing different origins of silver ore.