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/None (conchoidal fracture); Specific gravity: 2.65.

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

Identified June 15, 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/None (conchoidal fracture); Specific gravity: 2.65.

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal veins. It can be found in almost all geological environments and across all geological ages, often as the last mineral to crystallize in igneous rocks.

Uses & applications

Used in electronics for its piezoelectric properties (timekeeping, sensors), glassmaking, abrasives, gemstones for jewelry, and as a popular specimen for collectors and metaphysical practitioners.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Pure quartz is known as 'Rock Crystal' and was believed by the ancient Greeks to be ice that had frozen so hard it would never melt.

Field identification & locations

Identify by its hardness (scratches glass), hexagonal crystal habit with horizontal striations on the prism faces, and lack of cleavage. It is found globally, with famous deposits in Brazil, Arkansas (USA), and the Alps.