Tags: Chemical Substance, Mineral.
Mullite or porcelainite is a rare silicate mineral of post-clay genesis. It can form two stoichiometric forms 3Al2O32SiO2 or 2Al2O3 SiO2. Unusually mullite has no charge balancing cations present. As a result there are three different Al sites: two distorted tetrahedral Al sites and one Al other site which adopts a higher co-ordinate octahedral state.Mullite was first described in 1924 for an occurrence on the Isle of Mull Scotland.