An Investigation of Glassmaking Industry at Tal-i Malyan Based on PIXE Analysis

Glass can be defined as an inorganic melted product that has solidified without crystallization. Glass-making industry has an ancient history and background in Iran. In Sasanian period, this industry along with other industries attained a considerable development in manufacturing techniques, designs and decoration methods. Surprisingly, little has been published on the detail of technologies they employed, studies which have been accomplished are restricted to classification and typology of objects and artifacts. Therefore, this research tries to illuminate the unknown parts of this industry by using archaeological sciences and variation of statistical studies. The particle induced X-ray emission spectroscopy (PIXE) is a remarkable tool for the scientific investigation of cultural heritage. Study of glass-making structures in Sasanian period at Tal-i Malyan -considering manufacturing techniques and raw materials- is the main purpose of this research. Tal-i Malyan is located in Baiza district of Fars province in Iran. It lies 43 kilometers west of Persepolis, near the western edge of a large intermountain valley system drained by the Kur River, at an altitude of 1500 meters. Although first occupied in the Jari period (5500 B.C.) or earlier, evidence of later occupation such as Sasanian pottery kiln and coins found in burials, demonstrate Parthian and Sasanian settlements in Malyan. Hence, a group of 26 glass object fragments from Tal-i Malyan were selected as a case study in order to analyze them using PIXE method to determine the raw materials and technological aspects of their production and use. In addition, scanning electron microscopy in combination with energy dispersive X-ray microanalysis (SEM-EDS) images was used to gain a better understanding about the weathering process and decoration details. Applying statistical analysis such as cluster analysis has led to identify two glass recipes, different source of raw materials and different production technologies for manufacture of glass frit. The analytical data suggest that both soda-lime-silicate and potash-lime-silicate were producing in this area. Furthermore, iron and manganese contents show that the furnace temperature was mainly responsible for the development of green, blue and blue-green hues. Also, the presence of glass frits, quartz crystals and milky quartz indicates that the glassmaking manufacturing was a common and domestic industry in Malyan.