Arabic Weights from Armant
Glass weights were used to measure metals. Some weights have inscriptions with the name of the local governor or official in charge of measures.
For more information:
Petrie, W.M.F. 1926. Ancient Weights and Measures. London: British School of Archaeology in Egypt.
Balog, P. 1976 Umayyad, Abbasid and Tulunid Glass Weights and Vessel Stamps New York: American Numismatic Society.
Miles, G.C. 1948 Early Arabic glass weights and stamps. With a study of the manufacture of eighth century Egyptian glass weights and stamps, by Frederick R. Matson. New York: American Numismatic Society.