Possible raw material for manufacture of helenistic pottery on the island of Vis, Croatia

The ancient Issa, one of the oldest urban nucleus in Croatia, is situated on the island of Vis. Archaeological excavations have yielded many artefacts (pottery kilns, moulds, fragments of pottery waste, vessels with distinctive shapes and decoration) which indicate local pottery production within the settlement during the Hellenistic and Early Roman periods. The subject of this study is possible raw material of local origin for its production. Clayey material, as well as possible temper material were sampled from several locations on the island. Different types of sampled clayey materials include: relatively pure clays found in the vertical cracks within Cretaceous limestones and in some other restricted areas on the island; terra rossa, Pleistocene paleosol rich in clay; and material formed by weathering of volcanic rocks. Possible temper materials sampled are: Quaternary quartz sands, probably of aeolian origin and Albian quartz sediments of unknown origin. Current investigations are based on detailed mineralogical analyses of ceramic fragments and possible raw materials. Mineralogical analyses include powder XRD analyses of bulk samples, as well as XRD analyses of random and oriented samples of the clay fraction of clayey material