The archaeometry of Roman and Medieval glass: bulk characterisation and alteration processes. Raw materials for Roman glass: an experimental study

In the present study, the following aspects were developed: 1) Bulk characterisation, with the aim of identifying raw materials and glass-making techniques. Particular emphasis is given to glass production in the Campania region which - documented by historical sources and archaeological evidence, but hotly debated as regards reliability – was flanked by experimental study to verify sources, with particular reference to the use of sand from beaches as a possible source of supply. 2) Alteration processes due to interactions between the geochemical environment of conservation and glass composition. The samples studied here, covering a large time-span from Roman to Late Medieval times, were selected not only according to archaeological indications, but also to the mineralogical and geochemical features of the environment. Thus, four archaeological sites, characterised by conservation in both submarine (the ship Iulia Felix) and land-based conditions (Grado, Vicenza, Pozzuoli) were chosen. Numerous and integrated analytical techniques were used: optical analyses, X-ray spectrometry, scanning electron microscopy, X-ray powder diffraction, Mössbauer spectroscopy, thermogravimetric and thermodifferential analyses, oxygen isotope analysis, and transmission electron microscopy.