Kaolin, or china clay, is a clay made mainly of the mineral kaolinite, Al₂Si₂O₅(OH)₄. It takes its name from Gaoling, a hill in Jiangxi province in China where it was mined for porcelain.
Kaolin fires white and withstands high temperatures, so it sets the colour and the refractoriness of a porcelain body. It is not very plastic on its own; more plastic clays are added to make the body workable.