Roman coins at the edge of the Negev: characterisation of copper alloy artefacts and soil from Rakafot 54 (Beer Sheva, Israel)

Abstract

The research presented in this paper focused on the preliminary non- and semi-destructive analysis of copper alloys, corrosion, and soil components from a Roman archaeological site in Israel. Investigations using portable X-ray fluorescence, X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy as well as micromorphological analyses were carried out to gain a better understanding of the corrosion processes affecting the copper alloy artefacts, by characterising the alloy composition, soil environments, and corrosion products. Preliminary results indicate that the artefacts consist of copper-lead-tin alloys, covered by copper hydroxy-chlorides and lead sulphate phases with slight variations in their crystallisation. The multi-analytical approach revealed the presence of quartz, calcite, gypsum and feldspars in the sediments, while thin sections more specifically indicate loess soils with local micro-environments