Archaeometrical analyses of early egyptian glass from Thebe area.

In this work a series of fragments of Egyptian unguentaria are characterized from the chemical and physical point of view. The analysed samples were produced in the first step of the Egyptian glass production, during the new Kingdom of Egypt. The glass production in Egypt started under Thumosis III kingdom and developed until it reached its maximum during the kingdom of Amenhotep III (XVIII dinasty, 1390-1352 BC.) e Amenhotep IV/Akhenaton (XVIII dinasty, 1352-1338 BC). In this period, different glass shapes and typologies appears, and also the variety of decorations and colours increased. The analysed samples pertain to six vessels (amphoriskoi and krateriskoi) coming from Thebes area and now stored at the Egyptian Museum of Turin (Italy) after the excavation carried out at the Valley of the Queens. All these vessels, are blue with yellow, white and turquoise decorations and were produced with the core forming technique. The chemical analyses of major and minor elements were performed by Electron Microprobe (EMPA). The nature of the opacifying and colouring agents was determined by X-ray powder diffraction. Since only micro volumes were sampled from the artefacts (less than 1 mm3), the diffraction experiments were successfully carried out using a single crystal diffractometer equipped with a CCD camera. The chemical data obtained show that all the samples contain high levels of Na2O. However, along with a number of glass containing rather high level of both MgO and K2O - thus classified as plant ash based glass - some of them show rather low levels of K2O along with high MgO percentages. Most of these low-potassium high-magnesium samples are Al- rich Co-bearing blue glass: this seems to indicate they were probably coloured with the addition of Co-bearing alum. This is also consistent with the high level of MnO present in these samples. This situation suggests the use of two different kinds of flux for the production of these glass: an organic source (for the production of most of yellow, white and turquoise glass) and an inorganic one (leading to lower levels of K and Mg) used for the production of the Co-bearing samples. Yellow opaque decorations are rich in Pb and Sb, while only Sb is present in the white and light blue ones. This is consistent with the results of the X-ray powder diffraction analyses, that confirmed the presence of lead antimonates in the yellow decorations and of calcium antimonates in white and light blue ones. No crystalline phases were detected in dark blue, black and violet bulk glass.