Metallurgical analysis of bronze coinage from the Seleucid Empire

Bronze coinage of the Seleucid Empire is well documented in numismatic literature, yet little archaeometallurgical work has been conducted on these artifacts. In particular, certain Seleucid bronze coins exhibit distinctive serrated or bottle-cap edges. The method by which this distinctive feature was manufactured remains uncertain. Numismatic studies generally attribute these serrations to mechanical notching of the coin edge after striking, though this hypothesis has not been tested using metallurgical analysis. The present study presents a comprehensive metallurgical examination of several Seleucid bronze coins obtained from a legally exported private collection. On select coins, alloy compositions, mechanical properties, and microstructures were examined. Inductively coupled plasma (ICP) analysis was used to assess composition, microhardness and various metallographic techniques were used to characterize cross-sections of the coins, including light optical microscopy (LOM) scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD). Microstructural characterization of the coin interior and serrated edges provided insight into flan production, striking deformation, and the formation of serrated edges in Seleucid bronze coinage.