XRF and micro-PIXE studies of inhomogeneity of ancient bronze and silver alloys

New results regarding alloy composition and microstructure for a series of ancient bronze and silver items by X-ray Fluorescence and micro-Particle Induced X-ray Emission spectrometry were obtained in the framework of an extensive numismatic project (Scythian-type arrowheads, arrowhead-shaped monetary signs and wheel coins produced by Histria, 7th-4th century of BCE, and Dacian Radulesti-Hunedoara-type silver tetradrachms, 2nd-1st century of BCE). In Histria, warfare arrowheads were used for trade with Barbarian neighbors at first, then mechanically modified, next melted and cast as dedicated monetary signs, being, in the end, replaced by wheel coins. Three different types of alloys have been identified, and Cu-Mn and Cu-Pb segregation shown. In a blank for Radulesti-Hunedoara-type coins, Ag-(Cu+Pb) segregation has been demonstrated, suggesting an imperfectly alloyed silver-leaded bronze.