The Compositional Analysis of Mineral Content and Geo-Chemistry of the Ancient Grey Potsherds from Shahr-I Sokhta, East of Iran

This study aimed to determine whether grey pottery shards from Shahr-I Sokhta were locally made or imported. Shahr-I Sokhta is one of the biggest ancient sites of Iranian civilization in southwest Asia, which is located in the Sistan Region, East of Iran, and its area is about 270 hectares. The site has been registered as a UNESCO World Heritage in 2014. Archaeologists believe that most of the pottery shards are locally made; hence, to test this hypothesis, a scientific analysis was done to determine the chemical composition of the pottery shards. X-Rays Fluorescence (XRF) was applied to determine the major and trace elements of the pottery shards while The X-Ray Diffraction (XRD) was employed to characterise and compare the mineral phases. The results demonstrate that most of the pottery shards are in the same group, and this strongly suggests that they are local products. Based on minerals existing in the pottery shard, it is indicated that the pottery shards were baked at very high temperatures. The high concentration of copper in the pottery shards shows that the pottery was glazed with a mixture of copper oxide. Copper oxide was added as colouring agents in the glazed mixture, giving a grey colour to the surface of the vessels. The concentration of lead is normal and minimal; usually lead is added as a colouring agent into the pottery. The ancient potters in Indus Valley always used lead as a colourant.