Rock Identifier
Quartz (Silicon Dioxide (SiO2)) — mineral
mineral

Quartz

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Colorless to white (milky) with iron staining; Luster: Vitreous (glassy); Crystal Structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness
7 on Mohs scale
Color
Colorless to white (milky) with iron staining
Luster
Vitreous (glassy)
Identified More mineral

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Physical properties

Hardness: 7 on Mohs scale; Color: Colorless to white (milky) with iron staining; Luster: Vitreous (glassy); Crystal Structure: Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed from the crystallization of silica-rich magma or precipitation from hydrothermal veins. It is a major constituent of many igneous, metamorphic, and sedimentary rocks across all geological ages.

Uses & applications

Used extensively in glassmaking, electronics (piezoelectric properties), abrasives, and as a semi-precious gemstone in jewelry.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the German word 'quarz', which likely has Slavic origins meaning 'hard'.

Field identification & locations

Identify by its ability to scratch glass and lack of cleavage. Often found as veins in other rocks or as translucent pebbles in riverbeds and on beaches worldwide.