It occurs associated with staurolite, andalusite, sillimanite, talc, hornblende, gedrite, mullite and corundum. The three minerals are calcined to form mullite. The matrix materials are usually the same, that is C, SiC, alumina and mullite. In this case, there are two common morphologies for mullite. Mullite morphology is also important for its application. Dumortierite and mullite are similar mineral species found in porcelain. Mining of bauxite and kaolinite is currently being done by Mullite Company of America (Mulcoa). Unusually, mullite has no charge balancing cations present. Mullite is present in the form of needles in porcelain. Mullite is a compound of alumina and silica, with the formula 3Al2O3-2SiO2. Mullite was first described in 1924 for an occurrence on the Isle of Mull, Scotland.