Analytical Characterization of an Ottoman Opus Sectile Mosaic Floor from the Delta Region, Egypt

This study reports a recent analytical study of the main components of an opus sectile mosaic floor from an Ottoman bath (hammam) in the delta region of Egypt, that dates back to 1748 CE. Samples of the decorative elements of the mosaic floor including white stone, pottery mosaic pieces, black stone and setting bed mortar from the mosaic substrate were collected and analyzed. The microscopic features of the samples were examined by an optical USB digital microscope and their petrographic characteristics were evaluated by a polarized light microscope. The morphological and chemical composition of the samples were determined by a scanning electron microscope provided with an X-ray microanalyzer (SEM-EDX). The crystalline phases contained in the samples were measured by X-ray powder diffraction analysis (XRD). The results have shown that the mosaic floor was constructed using a white marble which consists of multi-sized calcite crystals with minor amounts of coesite. The pottery mosaic pieces are composed of quartz, hematite and albite. The black stone was identified as a volcanic rock of basalt which consists of andesine, anorthite and accessory quartz. A traditional lime mortar composed of quartz and calcite was used as a setting bed mortar for the mosaic pieces. Furthermore, the results showed the detection of some salt minerals which reflects the salt weathering that occurs in the site. The obtained results provided useful information on the technical structure of the studied mosaic and will be used to select appropriate materials for its restoration.