Kaolin is a clay mineral consisting of the mineral kaolinite (cf. chemical data) with admixtures of quartz and feldspar. Kaolin indicates a grain size of 0.2-1µm, which is clearly in the colloidal range. Kaolin is used as a high temperature bonding agent in ceramics as well as a constituent in coatings. At temperatures >1500°C kaolin is converted into mullite. Further it is a filler in the paper industry. The more rarely occuring minerals dickite and nakrit have the same chemical formula as kaolinite, however they differ in the type of stacking the Al₂[(OH)₂|Si₂O₅] -layers.