mineral

Milky Quartz

Silicon dioxide (SiO2)

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

Hardness: 7 on Mohs scale
Color: Cloudy white to opaque
Luster: Vitreous to greasy

Identified April 12, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Cloudy white to opaque; 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 hydrothermal fluids in veins or as a late-stage mineral in igneous pegmatites. The 'milky' appearance is caused by tiny fluid or gas inclusions trapped during crystal growth.

Uses & applications

Used in glass manufacturing, as an abrasive, in electronics for its piezoelectric properties, in jewelry (cabochons), and as a landscaping stone.

Geological facts

Milky quartz is the most common variety of crystalline quartz. While it lacks the transparency of rock crystal, the microscopic bubbles that give it color can sometimes provide clues to the temperature and pressure at which the mineral formed.

Field identification & locations

Identify in the field by its ability to scratch glass, lack of cleavage, and white 'milky' color. It is found globally in vast quantities, particularly in mountain ranges and gravel deposits.