mineral

Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale). Color: Colorless/Transparent. Luster: Vitreous (glass-like). Crystal structure: Hexagonal/Trigonal (six-sided prisms). Cleavage: None (conchoidal fracture). Specific Gravity: 2.65.

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

Identified February 5, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the cooling and crystallization of silica-rich magma or from hydrothermal solutions in veins and cavities. It is found in all geological environments and across all ages of Earth's history.

Uses & applications

Used extensively in electronics for its piezoelectric properties, glassmaking, construction (as a component of granite and sand), and as a gemstone or specimen for jewelry and collectors.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is highly resistant to both chemical and physical weathering. Famous specimens are often found in Arkansas (USA) and Brazil.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), its lack of cleavage, and its characteristic six-sided crystal habit. It is found globally, common in mountain ranges and riverbeds. Collectors look for terminated points and clarity.