Polychrome etruscan glass: FIRST NON-DESTRUCTIVE CHARACTERISATION WITH SYNCHROTRON mXRF, mXANES and XRPD.

This work is devoted to the characterization ofa suite of very rare, highly decorated and coloured glass vesselsand beads from the VII to the IV century BC. The most seriousdifficulty in developing this study was that any sampling –even micro-sampling – was absolutely forbidden. As a consequence,themineralogical and chemical nature of chromophoresand opacifiers present in these Iron Age finds were identifiedby means of the following synchrotron-based, strictly nondestructive,techniques: micro X-ray fluorescence (μ-XRF),FeK-edge micro X-ray absorption near edge spectroscopy (μ-XANES) and X-ray powder diffraction (XRPD). The μ-XRFmapping evidenced high levels of Pb and Sb in the yellow decorationsand the presence of only Sb in the white and light-blueones. Purple and black glass show high amounts of Mn andFe, respectively. The XRPD analyses confirmed the presenceof lead and calcium antimonates in yellow, turquoise and whitedecorations. FeK-edge μ-XANES spectra were collected in differentcoloured parts of the finds, thus enabling the mapping ofthe oxidation state of these elements across the samples. In mostof the samples iron is present in the reduced form Fe2+ in thebulk glass of the vessels, and in the oxidized form Fe3+ in thedecorations, indicating that these glass artefacts were producedin at least two distinct processing steps under different furnaceconditions.