Kaolin is a clay mineral with the chemical composition 2SiO2, Al2O3, 2H2O it is a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina octahedral. Rocks that are rich in kaolin are knows as china clay or kaolin.

Two main types of fused aluminas are available: white and brown fused aluminas. Fused aluminas are single crystal products.

These Low Soda Aluminas are ball-milled down to the primary crystal size ranging from 0.4 to 2.5 µm.