Hard-paste porcelain
Hard-paste porcelain is a hard, dense ceramic made from a compound of the feldspathic rock petuntse and kaolin fired at very high temperature. It was first made in China around the 9th century.
The secret of its manufacture was not known in Europe until 1709, when Böttger of Meissen, Germany discovered the formula. Despite attempts to keep it secret, the process spread to other German ceramic factories and eventually became known throughout Europe.