Basilica of San Marco (Venice, Italy/Byzantine period): Nondestructive investigation on the glass Mosaic Tesserae

► We studied the glass mosaics of a coherent fragment of the San Marco Basilica Venice. ► PIXE-PIGE, p-XRF, laboratory and portable OM, scanner and XPS results were compared. ► p-XRF and PIXE-PIGE results are comparable when heavy elements are present. ► Nonhomogeneous tesserae were related to artistic needs or ancient substitutions.