mineral

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Hardness: 7 on the Mohs scale; Color: Colorless/Transparent; Luster: Vitreous (glass-like); Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

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

Identified March 14, 2026More mineral →

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Physical properties

Hardness: 7 on the Mohs scale; Color: Colorless/Transparent; Luster: Vitreous (glass-like); Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Formation & geological history

Formed through the cooling and crystallization of silica-rich magma or from hydrothermal solutions in veins. It is found in a wide variety of geological environments ranging from igneous to metamorphic and sedimentary rocks across all geological ages.

Uses & applications

Used in electronics (oscillators), optical instruments, glassmaking, and construction (as silica sand). Extensively used in jewelry as semi-precious gemstones and by collectors for crystal clusters.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Ancient Greeks believed clear quartz was deeply frozen ice (krystallos) that would never melt. It exhibits piezoelectricity, meaning it generates an electric charge when mechanical stress is applied.

Field identification & locations

Identify in the field by its hardness (will scratch glass and steel), lack of cleavage, and hexagonal crystal habit. Found globally, with significant deposits in Brazil, Arkansas (USA), and the Alps.