mineral

Quartz (Milky/Common Quartz)

Silicon Dioxide (SiO2)

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

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

Identified April 17, 2026More mineral →

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Physical properties

Formation & geological history

Formed through crystallization of igneous magma or from hydrothermal veins. It is one of the most abundant minerals in Earth's crust and is found in all three types of rocks (igneous, sedimentary, and metamorphic).

Uses & applications

Used in glassmaking, abrasives, silicon production for electronics, construction aggregate, and as a component in quartz countertops. Common specimens are also collected by hobbyists.

Geological facts

Milky quartz gets its cloudy appearance from microscopic inclusions of fluids or gas trapped during the crystal's formation. It is the most common variety of crystalline quartz.

Field identification & locations

Identify in the field by its hardness (it will scratch glass and steel), lack of cleavage, and its characteristic vitreous luster. It is found globally in mountains, rivers, and beaches.

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