mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

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

Hardness: 7 on Mohs scale
Color: White to cloudy/milky
Luster: Vitreous to greasy

Identified July 20, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed from silica-rich hydrothermal fluids in veins or as part of igneous pegmatites. The milky appearance is caused by microscopic fluid inclusions of gas or liquid trapped during crystal growth.

Uses & applications

Used as a source of silicon for electronics, as an abrasive, in glassmaking, and as decorative stone or gravel in landscaping.

Geological facts

Milk quartz is the most common variety of crystalline quartz. While it lacks the transparency of rock crystal, it can sometimes contain inclusions of gold or other valuable minerals in hydrothermal vein systems.

Field identification & locations

Identify in the field by its hardness (will scratch glass), lack of cleavage, and white cloudy appearance. It is extremely common worldwide and often found as weather-resistant pebbles in stream beds.