X-ray diffraction has been used to analyse pottery from two late Roman-early Migration Period sites in western Norway. The presence of illite and illite/smectite in blackburnished ware from inhumation graves suggests that this ware was never subjected to tempera-tures as high as 375° C. The absence of these heat-sensitive clay minerals in red ware from cremation graves at these sites suggests a secondary firing at 700 800° C. The clay minerals are similar in the cores and surfaces of the black pottery which suggests that the color differences are due to firing procedures. Chlorite is present in all of the samples, an indication that the ware originated in a specific workshop. -- AATA