betaquartz

Beta-quartz is the high-temperature polymorph of quartz, the mineral form of silicon dioxide (SiO2). It is the phase that quartz adopts when subjected to elevated temperatures, in contrast to the more familiar alpha-quartz that occurs at lower temperatures.

In beta-quartz, the crystal structure has higher symmetry than in alpha-quartz and belongs to a hexagonal arrangement of the silica framework. The silicon-oxygen tetrahedra remain linked in a continuous SiO2 network, but the lattice parameters and symmetry differ from the low-temperature form. This phase is stable above approximately 573°C (846 K) at ambient pressure.

The beta-to-alpha transition is reversible and occurs on cooling below about 573°C. When beta-quartz is cooled, it transforms to alpha-quartz, and the process is typically rapid enough that beta-quartz rarely persists in natural surface rocks. As a result, natural quartz material found at Earth’s surface is usually alpha-quartz, with beta-quartz seen mainly in high-temperature experimental settings or in synthetic materials produced under controlled heating.

Natural occurrence and uses: Beta-quartz is of interest primarily in studies of phase transitions in silicate minerals and in high-temperature synthetic processes. Its presence helps researchers understand the behavior of silica under thermal variations and provides a comparative model for displacive phase transitions in quartz-family minerals.

Compared with alpha-quartz, beta-quartz exhibits different symmetry properties and spectroscopic signatures, reflecting its distinct high-temperature structure while maintaining the same chemical composition.