Study of Chemical Structure of Glass Samples belong to Sirvan Historical Site, Ilam Province

Sirvan historical site is located in Sarāb Kalān village in northern area of Ilam province and according to experts and remains belongs to Sasanian and Early-Islamic periods. The purpose of this research, for the first time, was to investigate the chemical structure of 10 glass fragments (mainly including parts of the body of the vessel) obtained from geoarchaeological studies of this area, using XRF analytical method. The results of analysis show that these samples have been classified in the group of alkaline glass (silica - soda - lime) and according to the ratio of their alkaline elements, vegetable ash (probably local plants) has been used to prepare the glass load. The average weight percentage of silicon oxide is 60.97 with a variance of 15.100 and due to the amounts of aluminum and iron oxides, different sources of silica with low purity have been used in the production of these glasses. Observing variation in amounts of elements in glass lattice and lack of correlation between elements, strengthens the hypothesis of diversity and alteration in primary sources. Also, a comparative study between these samples with the analytical results of glass artifacts belonging to the closest historical sites to Sirvan (Goryeh and Jahangir Dome), indicates that probably the samples of Sirvan are older than these two sites, and trial and error has been played a main role in their production.