Precision in the X-ray fluorescence analysis of sixty-one Augustan quadrantes

Sixty-one Augustan quadrantes were analysed for calcium, iron, nickel, copper, silver, tin, antimony, and lead by X-ray fluorescence. Most coins contained about 99·7% copper with the other seven elements present as trace impurities. Significant differences in composition were found for the three different issues of quadrantes minted in c. 9 BC indicating that these issues were not minted exactly contemporaneously. Quadrantes minted in c. 4 BC have trace element concentrations in ranges that differ from those of the 9 BC quadrantes. The precision is very good for all trace elements (the precision of calcium was not calculated): average standard deviations are 0·0021% for Fe, 0·0026% for Ni, 0·0038% for Ag, 0·0014% for Sn, 0·0031% for Sb, and 0·015 for Pb.