mineral

Quartz (Milky/Crystalline)

Quartz (Silicon Dioxide, SiO2)

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

Hardness: 7 on Mohs scale
Color: Colorless to white/milky
Luster: Vitreous (glassy)

Identified March 14, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Colorless to white/milky; Luster: Vitreous (glassy); 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 in all geological ages and across igneous, metamorphic, and sedimentary environments.

Uses & applications

Used in glassmaking, abrasives, electronics (piezoelectric properties), construction as a component of concrete/mortar, and as a semi-precious gemstone in jewelry.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Ancient Greeks called it 'krustallos', meaning 'ice', because they believed it was ice frozen so hard it would never melt.

Field identification & locations

Identify by its ability to scratch glass and lack of cleavage. Look for it in riverbeds, mountain outcrops, and as white 'veins' in darker rocks. Found globally, extremely common in Arkansas (USA), Brazil, and the Alps.

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