A hard, white, translucent ceramic body, which is fired to a high temperature in a kiln to vitrify it. It is normally covered with a glaze and decorated, under the glaze (usually in cobalt), or, after the first firing, over the glaze with enamel colours. If left unglazed it is called biscuit porcelain. It is usually divided into two types, hard-paste, or true porcelain, and soft-pase, or artificial porcelain. True porcelain was first made by the Chinese in the 7th or 8th century ad, using kaolin (china clay) and petuntse (china stone), which were easily available.