R2: Crystal structure, crystal chemistry, physical properties of minerals, crystal growth and applied mineralogy

[R2-03] Crystallization of Tridymite in CaO-MgO-Li₂O-V₂O₅ Flux

*Toshiya Abe¹ (1. Yamaguchi Univ. Sci.)

Keywords:synthesis, flux, amorphous silica, tridymite, cristobalite

We have revealed the crystallization conditions of tridymite from amorphous silica, a starting material, in the flux system CaO-MgO-Li₂O-V₂O₅. At experimental temperatures from 1000 to 800ºC, metastable cristobalite crystallizes preferentially, and tridymite appears subsequently. At prolonged heating, tridymite is dominant and cristobalite disappears. This change completes in a shorter time at higher temperature. Quartz, even under stable conditions, have observed only in limited cases.