mineral

Milky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale), Color: White, cloudy, or milky, Luster: Vitreous to greasy, Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Identified April 30, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 7 (Mohs scale), Color: White, cloudy, or milky, Luster: Vitreous to greasy, Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Formation & geological history

Formed through the crystallization of silica-rich magma or from hydrothermal veins. The milky appearance is caused by tiny inclusions of gas or liquid trapped during crystal growth. They can be found in a wide variety of geological ages.

Uses & applications

Used as an abrasive in sandpaper, in glass manufacture, as a flux in metallurgy, and as common landscaping or decorative stone. Sometimes used in jewelry as cabochons.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz specifically gets its name from its translucent to opaque white color which resembles milk.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), its white color, and its lack of cleavage. It is found globally in igneous, metamorphic, and sedimentary environments.