A multi-spectroscopic approach to the characterization of early glaze opacifiers: Studies on an Achaemenid glazed brick found at Susa, south-western Iran (mid-first millennium BC)

This paper presents the results of micro-Raman spectroscopy, energy dispersive X-ray fluorescence (XRF), and scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM–EDS) studies performed on an Achaemenid glazed brick found at Susa (mid-first millennium BC). The results showed that calcium antimonate (CaSb2O6) and lead antimonate (Pb2Sb2O7) were used as white and yellow opacifiers in the white and orange glazes respectively. Moreover, the mixture of calcium antimonate and lead antimonate were used as opacifier in the green glaze. In addition, green, turquoise, blue, and orange colors were achieved by the dissolution of copper, cobalt, and iron-bearing materials in an alkali glaze. A black glazed line, whose color was obtained by copper and iron oxides, was used to separate the colored glazes. The present paper strongly suggests invasive micro-Raman spectroscopy for the identification of the opacifiers used in the early vitreous materials.