mineral

Quartz

SiO2 (Silicon Dioxide)

Hardness: 7 on the Mohs scale; Color: Clear to milky white; Luster: Vitreous (glassy); Crystal structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 on the Mohs scale
Color: Clear to milky white
Luster: Vitreous (glassy)

Identified June 2, 2026More mineral →

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Physical properties

Hardness: 7 on the Mohs scale; Color: Clear to milky white; Luster: Vitreous (glassy); Crystal structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Quartz forms in a wide variety of environments, most commonly by the cooling of silica-rich magma or from hydrothermal veins. It is found in igneous, sedimentary, and metamorphic rocks across all geological ages.

Uses & applications

Extensively used in glassmaking, abrasives, electronic oscillators (clocks and radios), jewelry as semi-precious gemstones, and as a component in construction concrete and mortar.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'quarz', which has origins in Slavic and Greek words meaning 'hard'. It is piezoelectric, meaning it generates an electric charge when mechanical pressure is applied.

Field identification & locations

Identifiable in the field by its hardness (scratches glass/steel), conchoidal fracture (no flat cleavage planes), and glassy luster. Common in sandy soils, riverbeds, and as veins in mountain outcrops. For collectors, look for crystal terminations.