X-ray fluorescence imaging analysis of inscription provenance

A stone tablet from New York University considered to be a copy of an inscription from Teanum Sidinicum is examined with X-ray fluorescence (XRF) and XRF imaging. Fluorescence spectra show many of the same elements seen in ancient Roman inscriptions, but the fluorescence intensity from calcium is much weaker and that from many other elements is much stronger. The weak calcium fluorescence cannot be due to X-ray absorption by other elements present, and so the tablet is unlikely to be of marble. This conclusion is supported by X-ray diffraction and electron microprobe measurements. Unlike for other examined inscriptions, XRF imaging indicates little or no correlation between the variation of trace element concentrations across the tablet surface and the presence of characters. These results confirm that the inscription is a copy and demonstrate how XRF imaging can assist in evaluating inscription provenance.