COLOR ALTERATION OF ANCIENT EGYPTIAN BLUE FAIENCE

Four different colored faience tiles were found in South Tomb of King Djoser in Saqqara, Egypt. The tiles suffer from various deterioration aspects, mainly color alteration, which occurred as a result of the reaction between present salts and the free copper ions of blue faience and changing it into greenish blue, dark green, and light green. The aim of this work is to study the color change phenomenon of ancient Egyptian blue faience, used in the construction and decoration of the walls in the south tomb of King Djoser-Saqqara by means of light optical microscope (LOM), x-ray diffraction spectroscopy (XRD), and scanning electron microscopy/energy dispersion X-ray (SEM EDX) analysis. The obtained results revealed that the pigment material cuprorivaite (CaCuSi4O10) was used in glazing the tiles and imparted the blue color. Other blue pigment materials were used in conjunction with Egyptian blue such as turquoise [CuAl6(PO4)(4)(OH)(8)center dot 4H(2)O]. The results indicate that the first trials for producing Egyptian blue were not in the 4th dynasty as it has been declared by previous authors.