THE ROMAN MOSAIC TESSERAE FROM VILLA SAN PANCRAZIO (TAORMINA, ITALY): EDXRF AND RAMAN SPECTROSCOPY ANALYSES FOR MANUFACTURING ASSESSMENT

The excavation works of Villa San Pancrazio (Taormina, Italy) are bringing to light a vast, multi-layered, Roman-Imperial residential quarter featuring luxurious dwellings decorated with wall paintings and mosaic floors, pointing it out as one of the most extensive and significant archaeological sites of the city [1]. The stylistic and iconographic studies of the polychrome and black and white mosaics suggest a dating to the Middle Imperial period, during the II century A.D. Accordingly, the present work aims to provide a contribution for the assessment of the mosaics manufacturing technology through the analyses of the raw materials employed. For that purpose, a micro-destructive multi-analytical methodology, mainly based on the combination of energy dispersive X-ray fluorescence (EDXRF) and Raman spectroscopy, was used to characterize a wide selection of stone, ceramic and glass tesserae collected from different mosaics. In addition, semi-quantitative elemental data obtained for the black and white samples coming from the bichromatic mosaics were explored by means of Principal Component Analysis (PCA). The investigations provided interesting information about the natural lithotypes used, local and imported, and how artificial materials, i.e. ceramics, transparent and opaque glasses, were produced. Accordingly, the significant technical and qualitative level of the residences mosaic systems was ascertained, revealing the owners high socio-economic profile, and also yielding important clues on the economical and cultural exchanges with other areas of Italy and the Roman Empire.