The raw materials from which ancient potters formed their pots are most often an intricate mixture of particle sizes with mineralogical variations both within and among the size ranges. Any alteration of the particle size distribution of the raw materials through the removal of coarser size ranges (levigation) and/or the addition of coarse aplastic material (temper), has an effect on the mineralogical and chemical content of the ceramic clays and ultimately the finished ceramic. This paper examines the effect of particle size distribution on the mineralogical and chemical content of natural and levigated clays collected from a single locality in NE Syria.