Kaolinite (/ˈkeɪəlɪnaɪt/)[4][5] is a clay mineral, part of the group of industrial minerals with the chemical composition Al2Si2O5(OH)4. It is a layered silicate mineral, with one tetrahedral sheet of silica (SiO
4) linked through oxygen atoms to one octahedral sheet of alumina (AlO
6) octahedra.[6] Rocks that are rich in kaolinite are known as kaolin /ˈkeɪəlɪn/ or china clay.