Abstract
Clays for Karatsu ware were prepared from ground three sandstones by a stamp-milling and elutriation processes. The chemical and mineralogical properties were studied and compared with those of Amakusa pottery stones for Arita porcelain. Karatsu clays were composed of α-quartz, feldspar and kaolin minerals without sericite, and the mineral composition of normative α-quartz, feldspar and kaolin were 38–48, 26–37, 17–31 mass %, respectively. Coarse particles in Karatsu clays were angular and rough in shape, and had a very broad particle size distribution. Average particle sizes of coarse particles were 24–29 µm, and maximum particle size were 160–260 µm, respectively. Average particle size of coarse particles was four to five larger than that of Amakusa pottery clay.
