mineral

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Hardness: 7 on Mohs scale; Color: Opaque white to cloudy; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Opaque white to cloudy
Luster: Vitreous to greasy

Identified March 7, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Opaque white to cloudy; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Forms in hydrothermal veins or as a primary constituent of igneous rocks like granite. The white 'milky' appearance is caused by microscopic fluid inclusions of gas and liquid trapped during crystal growth. They can range from recent formations to billions of years old.

Uses & applications

Used as a common decorative gravel in landscaping, an abrasive in sandpaper, and a source of silicon for glass and electronics. It is very common for rock tumbling and as a basic collector's specimen.

Geological facts

Milky Quartz is the most common variety of crystalline quartz. It is often found in 'veins' that cut through other rock types. It is semi-translucent, meaning light can pass through the surface but you cannot see through it clearly.

Field identification & locations

Identify in the field by its white color and extreme hardness (it will easily scratch glass and steel). It is found worldwide in riverbeds, mountains, and gravel pits. For collectors, look for pieces with distinct crystal faces rather than smooth rounded pebbles.