Technology and composition of Roman pottery in northwestern Peloponnese, Greece

Abstract Roman ceramic red-painted and unpainted lamps from two workshops excavated in the area of Patras, NW Peloponnese, Greece were examined in order to determine the mineralogical characteristics of the raw materials used for their production and to elucidate the ceramic manufacturing technologies employed. Optical microscopy, X-ray diffraction analysis (XRD), inductively coupled plasma-emission spectroscopy (ICP-OES) and scanning electron microscopy (SEM-EDS) were the analytical techniques used. The preliminary results presented here indicate that calcareous clays were used in the manufacture of the pottery by the two workshops. Based on a number of mineral assemblages observed, the chemical composition of prograde mineral phases developed in the sherds, the variability of colours of the body of the sherds, the chemical composition of the sherds and the textural and vitrification structures, it is shown that the two workshops used oxidizing conditions in the kilns and firing temperatures ranging from about 850 to 1050 °C. Only small differences in the production technology, which has been used by the two workshops have been recognized, especially in the body preparation and in the clay to temper ratios.