A process is disclosed for the production of high purity mullites. The process involves reacting a mixture of aluminum alkoxide and silicon alkoxide with an atomic ratio (weight) of Al/Si in the range of 2-7 in an aromatic hydrocarbon solvent at a temperature of 200.degree.-350.degree. C. and calcining the resulting reaction product at a temperature above 900.degree. C. The mullite product obtained finds wide application as a high temperature service structural material such as for automotive engines and turbines as well as a support for combustion catalyst.