A type of soft porcelain that has been made in England since ancient times. It is a type of porcelain between hard porcelain and frit porcelain. The main ingredient is bone ash, which can be made from any animal bone, but bovine bone is used because it contains the fewest impurities. Since bone ash porcelain clay has little plasticity, it is often cast-molded. Firing is difficult because the shrinkage due to firing is very large and the viscosity of the glass phase produced is very small. Therefore, companies that could produce bone ash porcelain industrially were trusted to be the best. The base is embedded in silica sand packed in a saggars and fired at S.K. 8 to 11. After that, a frit glaze is applied and fired at approximately 1,050 degrees Celsius. Decorative objects and tableware are made exclusively. (Ceramics for Crafts)
