Physicochemical properties of glass tesserae in Roman Terrace House from ancient Antandros (Base glass, opacifiers and colorants)

Abstract

In this study, material characteristics of glass mosaic tesserae from Antandros ancient city, western Turkey, were investigated. The main objective of this study was to determine the compositional group of the glass tesserae. Their color, mineralogical, chemical and microstructural characteristics were determined using colorimeter, x-ray diffraction, x-ray fluorescence and scanning electron microscope. The results show that all the Antandros glasses were produced by using coastal sand as Levantine I glasses and exhibit similar compositions with natron type glasses (Roman type glasses), except for lower natron levels. Lower natron levels indicate that Antandros mosaic glass may have been produced in 7th century AD or natron may have been provided from a new flux source due to the shortage of Egyptian mineral soda or due to economic reasons glass manufacturers succeeded to produce same glass with low flux addition. Antandros glass tesserae were all opacified with antimony oxides and colored with transition metal oxides which are common used in Roman Period.