Making sense out of cents: compositional variations in European coins as a control model for archaeometallurgy

Abstract

Archaeometallurgy frequently seeks to correlate between the temporal and spatial distribution of ancient metal objects and their chemical composition. In this study, we examined whether and to what extent local or temporal deviations in the content of modern artifacts can be identified as a proxy for archaeological material that is typically less controlled and therefore more difficult to cluster. For this purpose, Euro coins of 10, 20 and 50 cents from Germany, France, Spain, Italy and Belgium, which are made of copper (Cu) with 5% aluminum (Al), 5% zinc (Zn) and 1% tin (Sn), were analyzed using a simple XRF analyzer. The mass ratios Sn/Cu and Zn/Cu were measured with a relative precision c.a. of 5%. The mean content of the coins from each country was then determined for 20–39 of them. The difference of the mass ratio Sn/Cu observed – from 0.0101 to 0.0111. One coin from Luxemburg shows differences in various areas of its surface of up to a factor of 1.5. Thus, the results of this small pilot research show that even in modern metal artifacts we can detect differences in metal content, which can be correlated to their production and utilization places. Therefore, this study can serve as a model for evaluating compositional variations noted in archaeometallurgical studies where the standard deviations are greater and the differences can be linked more readily to spatial and temporal differences.