Preliminary non-invasive study of Roman glasses from Jesolo (Venice), Italy

Archaeological excavations at ‘Le Mure’ site (Jesolo, VE, Italy) have followed each other since the sixties, when the first evidence of an Early Medieval church (6th–7th century AD) was found under the ruins of a Medieval Cathedral (11th–12th AD). The last few years of investigations by Ca’Foscari University have led to the collection of large amounts of glass fragments, including many tesserae, dating between the 4th and the 12th centuries AD. A selection of glass fragments and mosaic tesserae taken from the excavations performed in 2013–14 at this site were studied by means of reflectance spectroscopy in order to identify their chromophore ions, in particular Cu0, Cu2+, Co2+, Fe2+ and Fe3+, which were detected in both transparent and opaque samples. In addition, the use of high resolution close-up images allowed for the attribution of surface characteristics to specific manufacturing techniques, while glass chemistry was studied in order to group them into known compositional classes. This study, carried out by non-invasive analytical techniques that allowed for the acquisition of preliminary data, will prove useful in driving further methodologies involving other non-invasive and micro-invasive analysis in order to obtain archaeometric information that can be related to concurrent archaeological results.