It has the same chemical composition (Al2O3.SiO2) as sillimanite and andalusite. When heated, it changes to sillimanite at 1300 degrees Celsius and further decomposes into mullite and silicic acid at 1545 degrees Celsius. The material is usually used after being sintered at high temperatures to remove the abnormal expansion. It is found in Lapsable in India, Kenya in Africa, and Virginia, Georgia, and North Carolina in the United States. It is used in large quantities as the main raw material for sillimanite refractories. (“Ceramic Raw Materials”)
