Non-destructive Analysis of Byzantine Gold-Leaf Glass Tesserae Using Ion Beam Analysis

During the byzantine period gold-leaf glass tesserae were used in abundance for the creation of wall mosaics for the adornment of Byzantine churches. Metal-leaf glass tessera is a sandwich structure of two layers of glass (the support and the top glass) enclosing a metal leaf and its characterisation necessitates a more sophisticated approach compared to other glass tesserae. Studies of gold-leaf glass tesserae have been based on destructive analysis (cross-section analysis), however cultural heritage objects address for a different approach. The technical progress and accessibility to more elaborate techniques could facilitate a non-destructive research. The aim of this work is to present the potentials of a non-destructive and non-invasive methodology for the analysis of byzantine gold-leaf glass tesserae using ion beam techniques. The study of gold- leaf glass tesserae was carried out at the Byzantine Monastery of Daphni (11th century) Greece. The research combined systematic examination of tesserae and analysis of selected samples. Tesserae were analysed as received, using mainly Scanning Electron microscopy coupled with Energy Dispersive x-ray Spectroscopy (SEM/EDS) and Ion beam techniques. In the context of this contribution the results will be presented to demonstrate the efficiency of the selected methodology. μ-PIXE/PIGE analysis provided elemental analysis for both the glass layers and via elemental maps combined with photographic recording of analysed areas, direct information for technological features.