mineral

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale; Color: Colorless/transparent; Luster: Vitreous (glass-like); Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on the Mohs scale
Color: Colorless/transparent
Luster: Vitreous (glass-like)

Identified March 7, 2026More mineral →

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Physical properties

Hardness: 7 on the Mohs scale; Color: Colorless/transparent; Luster: Vitreous (glass-like); Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Forms in a wide variety of environments, most notably in igneous rocks like granite and through hydrothermal activity where silica-rich fluids cool and crystallize in veins or cavities. It can be found in rocks from virtually every geological age.

Uses & applications

Used extensively in electronics for its piezoelectric properties (watches, sensors), in glassmaking, construction (sand/aggregates), and popular in the jewelry and metaphysical markets as polished stones or points.

Geological facts

Quartz is one of the most abundant minerals in Earth's continental crust. Historically, the Greeks believed clear quartz was formed from ice that had frozen so hard it would never melt. High-quality clusters can grow larger than a person in specific cave environments.

Field identification & locations

Identify in the field by its 6-sided hexagonal prism shape ending in a pyramid, its inability to be scratched by a steel knife, and its glassy appearance without cleavage planes. Found globally, with notable deposits in Brazil, Madagascar, and Arkansas (USA).