Archaeological and scientific evidence for the production of early islamic glass in al-raqqa, syria

Archaeological excavations of an Islamic industrial complex in northern Syria at al-Raqqa have revealed comprehensive evidence for Abbasid high temperature industries. Amongst the evidence is some for glass production. The evidence included a glass workshop consisting of the remains of three-chambered ‘bee-hive’ furnaces and a centralised flue system, the debris of casting glass into blocks of three different sizes, glass moils of two diameters (the knock-offs from blowing irons) and discarded lumps of frit, a material produced by the initial stage in glass production. In addition, fragments of a second kind of glass furnace, a tank furnace, were found. Scientific analysis of the products and by-products of this glass industry using electron probe microanalysis has produced an unexpectedly wide range of glass chemical compositions. In some instances discrete compositions are correlated to the function of the glass such as its use to make cast blocks and window panes. In others instances, such as when it is used to make glass vessels, the same apparent degree of specialisation in the deliberate selection of particular glass raw materials is not evident. Scientific analysis of frit has shown that the glass used to make the windows for glazing the al-Raqqa palace complexes was made in al-Raqqa.