First Evidence of Roman Mosaic Glass Tesserae in Tessin Canton, Southern Switzerland

Abstract

The unplanned discovery of a Roman settlement referable to a prestigious villa at the beginning of the last century in Morbio Inferiore (Southern Switzerland, Tessin Canton) and later findings in the same area represented a unique opportunity to study the materials and the technology of production of 1st-4th century CE glass mosaic tesserae.The analysis of coloured and colourless tesserae was carried out combining non-invasive (hand-held X-ray Spectrometry; HH-XRF) and micro-invasive (Scanning Electron Microscopy coupled to microanalysis, SEM/EDS; Laser Ablation Inductively Coupled Plasma - Mass Spectrometry, LA-ICP-MS; X-ray Powder Diffraction, XRPD).The results clearly indicate that the flux used is natron and that the matrices can be classified as soda-lime and soda-lime lead glass. In addition, the analysis of the major elements and that of the opacifiers used confirms that they can be classified as Roman - Late Roman glasses, thus supporting the archaeological evidence.

Keywords: glass technology, glass tesserae, gold foil tesserae, Roman villa, Tessin Canton