Laser and electron beams physical analyses applied to the comparison between two silver tetradrachm greek coins

Physical analyses by laser ablation coupled to mass quadrupole spectrometry (LAMQS), energy dispersive X-ray fluorescence (EDX) induced by electron beam, scanning electron microscopy (SEM) and surface profilometry analysis (SPA) are applied to the investigation of two silver tetradrachms from Messana, in order to compare their elemental composition and structure. Quantitative analysis of the elemental composition and of the silver isotopic ratios have been carried out analyzing the surface patina of the two samples. Significant differences in the sulfur, chlorine and copper content, in the isotopic ratios and in the morphological aspects have been measured. The obtained results are presented and discussed from the point of view of the physical techniques useful to establish the differences between apparently true and false coins.