mineral

Milky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs), Color: White to translucent milky white, Luster: Vitreous (glassy) to greasy, Crystal Structure: Trigonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Identified July 17, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs), Color: White to translucent milky white, Luster: Vitreous (glassy) to greasy, Crystal Structure: Trigonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Formation & geological history

Formed through the cooling and crystallization of silica-rich hydrothermal fluids or magma. Its milky appearance is caused by microscopic inclusions of gas or liquid (fluid inclusions) trapped during crystal growth.

Uses & applications

Used in glassmaking, as an abrasive, in electronics for its piezoelectric properties, as landscaping stone, and as a common collector's mineral.

Geological facts

Milky quartz is the most common variety of crystalline quartz. While often overlooked for clearer varieties like rock crystal, it can contain traces of gold in hydrothermal vein deposits.

Field identification & locations

Identify by its hardness (will scratch glass), lack of cleavage, and white 'cloudy' appearance. It is found globally, particularly in mountainous regions and riverbeds.