porcelain [Ital. porcellana], white, hard, permanent, nonporous pottery having translucence which is resonant when struck. Porcelain was first made by the Chinese to withstand the great heat generated in certain parts of their kilns. The two natural substances used were kaolin, also known as china clay, a white clay free of impurities that melts only at very high temperature, and a feldspar mineral called petuntse that forms a glassy cement, binding the vessel permanently. Although proto-porcelain wares exist dating from the Shang, by the Eastern Han high firing glazed ceramic wares had developed into porcelain, and porcelain manufactured during the T'ang period (618–906) was exported to the Islamic world where it was highly prized. The ware was refined during the Sung period (960–1279). During the Yuan period (1280–1368), blue and white ware was produced by utilizing cobalt blue from the Middle East. The Ming period (1368–1644) developed this blue and white ware but used other colors as well. The Ch'ing period (1644–1912) designed porcelain especially for export often utilizing Western designs. In Europe porcelain was first commercially produced (1710) in Meissen, Germany. Most of the European porcelain is soft paste (made from clay and an artificial compound such as round glass) and is not as strong as the Chinese hard-paste porcelain. Important European centers for porcelain are Bow, Chelsea, Worcester, Staffordshire, Vienna, Meissen, Sèvres, Limoges, and Rouen.