Neutron Activation Analysis of Microgram Samples from 364 Gold Objects from a Sican Burial Site in Peru

872 metal rubbings, each weighing about 10 micrograms, were taken from 364 gold objects from an unlooted Middle Sicin (ca. 1000 A.D.) Peruvian burial site and the gold, silver, and copper contents were determined by neutron activation analysis. Almost all objects have contents that are in the range: 35-65% gold, 25-45% silver, and 10-30% copper. Objects of similar style were more uniform in content; for example, the 28 bangles and 90 feathers from the main headdress have gold contents that range only from 46-56% and 37-45%, respectively. Some objects have contents markedly different from the rest of the objects; ear-spools, for example, have very low copper (1-6%) and high gold (56-75%). A high degree of control of the alloy content is evident, with each alloy mixture probably being chosen to have desired color and mechanical properties. The data indicate that very consistent 1.0-1.1 mixtures of gold:silver were used for 136 of the 142 feathers whereas gold:silver mixtures closer to 1.3-1.9 were used for most of the 96 bangles.