Quartz

Quartz

Quartz is a mineral composed of silicon and oxygen atoms in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical formula of SiO2. It is the second most abundant mineral in Earth's continental crust, behind feldspar. Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation from α-quartz to β-quartz takes place abruptly at 573 °C (846 K). Since the transformation is accompanied by a significant change in volume, it can easily induce fracturing of ceramics or rocks passing through this temperature limit. There are many different varieties of quartz, several of which are semi-precious gemstones. Pure quartz, traditionally called rock crystal or clear quartz, is colorless and transparent or translucent, and has often been used for hardstone carvings, such as the Lothair Crystal. Common colored varieties include citrine, rose quartz, amethyst, smoky quartz, milky quartz, and others. Quartz goes by an array of different names. The most important distinction between types of quartz is that of macrocrystalline (individual crystals visible to the unaided eye) and the microcrystalline or cryptocrystalline varieties (aggregates of crystals visible only under high magnification).

silica, silicon dioxide, crystal, gemstone, piezoelectric, α-quartz, β-quartz, amethyst, citrine

— John Armstrong

CITATION : "John Armstrong. 'Quartz.' Design+Encyclopedia. https://design-encyclopedia.com/define/quartz?E=433234 (Accessed on October 14, 2026)"