Kaolinite
Kaolinite is a clay mineral, part of the group of industrial minerals, with the chemical composition Al2Si2O54. It is a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina octahedra. Rocks that are rich in kaolinite are known as
kaolin or
china clay. The name is derived from Chinese Kao-Ling, a village near Jingdezhen, Jiangxi province, China. The name entered English in 1727 from the French version of the word:
kaolin, following Francois Xavier d'Entrecolles's reports from Jingdezhen. In Africa, kaolin is sometimes known as
kalaba,
calaba, and
calabachop. Kaolinite has a low shrink–swell capacity and a low cation-exchange capacity. It is a soft, earthy, usually white mineral, produced by the chemical weathering of aluminium silicate minerals like feldspar. In many parts of the world, it is colored pink-orange-red by iron oxide, giving it a distinct rust hue. Lighter concentrations yield white, yellow or light orange colors. Alternating layers are sometimes found, as at Providence Canyon State Park in Georgia, United States.