Structural defects and polymorphic transformations in quartz

The influence of structural defects on the polymorphic transformations in quartz was studied by electron paramagnetic resonance and electron microscopy. It was established that the kinetics of the accumulation of the clusters of the β-phase depends on isomorphic impurities in quartz. It was confirmed that germanium ions and vacancies in quartz participate in the formation of the clusters. Obtained results allow the assumption that the amount of germanium required to preserve clusters increases with increasing temperature and vice versa. An explanation is presented for experimentally observed decomposition of clusters during artificial heating of some quartz samples. It was found that the clusters of the β-phase are autonomous units, i.e. may exist independently of host crystalline structure of quartz. The possible mechanism of influence of Ge impurity on the temperature of α-β-transition in quarts is discussed.