mineral

Quartz (Milky/Crystalline variety)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: White to translucent/clear, Luster: Vitreous (glassy), Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Identified June 19, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: White to translucent/clear, Luster: Vitreous (glassy), Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Formation & geological history

Forms in nearly all geological environments, most commonly from the cooling of magma or by hydrothermal precipitation in veins and cavities. It is a major constituent of continental crust.

Uses & applications

Used in electronics (oscillators), glassmaking, abrasives, jewelry, and as a semi-precious gemstone. High-purity quartz is critical for silicon wafers in the semiconductor industry.

Geological facts

Quartz is the second most abundant mineral in the Earth's continental crust. It is piezoelectric, meaning it generates an electric charge in response to mechanical stress.

Field identification & locations

Identify in the field by its hardness (will scratch glass and steel), lack of cleavage, and six-sided crystal habits. It is found globally, particularly in pegmatites and quartz veins.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral