The Chemical Composition of the Glass Items from the Medieval Cities in the Lower Reaches of the Syrdarya (Kazakhstan)

The article presents the results of the study of the chemical composition of glass products from medieval settlements located in the lower reaches of the Syr Darya in the Republic of Kazakhstan. The trade and craft centers of Kyshkala (Barshinkent), Asanas, Kumkala, Mortyk, Zhent existed from the early Middle Ages and during the Golden Horde period on one of the sections of the Silk Road. Medieval glass of Central Asia is an integral part of Islamic glassmaking, at the same time it shows a pronounced originality in glass chemistry due to the geobiochemical raw material features of the vast region. The composition of 20 samples of sodium ash glass of the Na2O-K2O-CaO-SiO2 type was determined using scanning electron microscopy (SEM-EDS). According to the concentration of glass-forming elements and their ratios within the type, three subtypes were distinguished, representing different technological traditions: Central Asia 75 %, Iran and Egypt 5 %.