Non-destructive characterization of Egyptian Blue cakes and wall painting fragments from the east of Lake Van, Turkey.

Abstract

A total of five Urartian blue cakes and two wall painting fragments, from excavations in different regions of the east of Lake Van, were analyzed by means of X-ray diffraction (XRD), micro-X-ray fluorescence spectrometry (μ-XRF), scanning electron microscopy combined with energy dispersive spectrometry (SEM-EDS) and Fourier-transform infrared spectroscopy (FT-IR). All the studies were performed non-destructively considering the great archaeological importance of the samples. The results indicate the presence of Egyptian Blue, which is the first synthetic pigment, consists of crystals of calcium-copper tetrasilicate (cuprorivaite, CaCuSi4Ol0) along with unreacted quartz (SiO2) and in some cases. Comparison of the elemental compositions of the samples from Egypt and Mesopotamia suggests that EB cakes may be local products due to the presence of zinc. The absence of Sn on the other hand, indicates that the source of the copper may be a copper ore not bronze scrap.