The Phenomenon of the Influence of Gold Melt on Microinclusions of Platinum Group Minerals in Ancient Gold Objects

This study focuses on microinclusions of platinum group minerals (PGMs) in gold objects from the South Urals and North Black Sea archaeological sites. We demonstrate for the first time that melting of gold during archaeometallurgical work affects PGM microinclusions. Desquamation of primary PGM microinclusions with 28–55 wt% Os in the melt and their oxidation by hot air microbubbles results in the formation of secondary particles with 1–20 wt% Os around the primary inclusions. We conclude that the composition only of primary PGM microinclusions in ancient gold products is comparable to the composition of those from natural sources.