mineral

Quartz (Milky/Common)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: White to translucent; Luster: Vitreous (glassy) to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: White to translucent
Luster: Vitreous (glassy) to greasy

Identified March 29, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: White to translucent; Luster: Vitreous (glassy) to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed from the crystallization of silica-rich magma or precipitation from hydrothermal fluids in veins. It is found across all geological ages from Precambrian to recent.

Uses & applications

Used in the manufacturing of glass, electronics (piezoelectric properties), abrasives, and as a semi-precious gemstone in jewelry or rock collections.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz gets its white, 'cloudy' appearance from microscopic fluid inclusions trapped during the crystal's growth.

Field identification & locations

Identify in the field by its hardness (it will scratch glass and steel) and its lack of cleavage. It is commonly found in gravel pits, riverbeds, and as veins within granite or metamorphic boulders.