Ceramics-Silikáty 20, (4) 303 - 319 (1976)

Most of the melts and glasses investigated crystallized in volume during heat treatment up to 1000 °C, The tendency to metastable separation, which precedes crystallization, increases with increasing MgO/Al₂O₃ ratio. The course of crystallization of the ZrO₂ phase, Mg petalite, solid solutions of β-quartz and enstatite depends on initial composition, way of treatment and crystallization temperature. Increasing crystallization temperature brings about decomposition of Mg petalite and precipitation of β quartz solid solutions. The composition region of metastable Mg petalite was determined by means of X-ray diffraction analysis.