mineral

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Colorless/Transparent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (Trigonal); Cleavage: Indistinct (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Colorless/Transparent
Luster: Vitreous (glassy)

Identified March 23, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Colorless/Transparent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (Trigonal); Cleavage: Indistinct (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Quartz forms in a wide range of environments, primarily through the cooling of silica-rich magma or from hydrothermal veins. It can be found in igneous rocks like granite, metamorphic rocks like quartzite, and sedimentary rocks as sand grains.

Uses & applications

Used extensively in electronics for frequency control (piezoelectric properties), glass manufacturing, abrasives, jewelry, and as a popular specimen for collectors and holistic practices.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure clear quartz is known as 'Rock Crystal' and was historically used to carve lenses and crystal balls.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), hexagonal crystal habit (six-sided prisms with pyramidal ends), and lack of cleavage. Common worldwide, with high-quality specimens frequently found in Brazil, Arkansas (USA), and the Alps.