Mineralogical and thermo-chemical characteristics of the Hellenistic ceramics and raw clay from Qizlar Qal'eh (northeastern Iran)

Hellenistic ceramics and a clay sample from the archaeological site of Qizlar Qal'eh in Gorgan plain, northeastern Iran were examined through microchemical, mineralogical and thermogravimetric-differential thermal analyses to characterize the provenance and thermal behavior of the ceramics from Seleucid and early Parthian periods (2268 ± 111BP, thermo-luminance date). Microstructural and mineralogical characteristics of the ceramics were also compared to the raw clay sample heated at two different heating rates. Thermal transformation of minerals and weight loss during firing indicate that the ceramic samples were locally produced and fired at different thermal stages at 718.1 °C and 1023.8 °C, 1047.7 °C which can be related to mineral decomposition, new-crystallization, partial sintering and sintering.