Morphological and chemical characterization of weathering products on buried Sasanian glass from central Iraq

The morphological and chemical features of the weathering products on Sasanian glass finds are discussed. The fragments were excavated at the ancient Sasanian town of Veh Ardašīr, some 30 km south of Baghdad (Iraq), and are dated from the third to the sixth century. They are all soda-lime glass, with MgO contents between 3% and 8%, resulting from the use of soda-rich plant ash as a flux; within this general frame, two productions can be distinguished due to their MgO to K2O ratio. Four main alteration typologies were observed by visual examination of the excavated samples and these were studied by scanning electron microscopy, energy dispersive X-ray analysis, inductively coupled plasma-mass spectrometry, X-ray diffraction and thermal analysis. Generally, different alteration features were observed for samples belonging to the two compositional groups.