Synthesis of mullite from oxides doped with topaz

Results of a study of the mullitization in stoichiometric pure oxides Al2O3 and SiO2 doped with topaz are reported. A mineralizing topaz-mediated effect is manifested in the activated synthesis of mullite of short prismatic habit involving products of thermal degradation of topaz (mullite and volatile fluorides). The volatile active fluorides enhance structural imperfections in the reactants and promote their high-temperature interaction. Mullite produced by thermal degradation of topaz plays the role of a seeding agent in the solid-state synthesis of mullite from oxides.