mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

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

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

Identified March 24, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed through the cooling of silica-rich magma or precipitation from hydrothermal veins. The milky appearance is caused by microscopic inclusions of gas or liquid trapped during crystal growth. They are found in geological environments ranging from Precambrian to Cenozoic eras.

Uses & applications

Used in glass manufacturing, as an abrasive, in the production of silicon chips, and as decorative gravel. Lower quality pieces are popular in rock tumbling and as 'curiosity' specimens for beginner collectors.

Geological facts

Milky Quartz is the most common variety of crystalline quartz. It is often found as the 'vein' material that carries gold in hydrothermal deposits. Its white color is essentially a record of ancient fluids trapped in the crystal for millions of years.

Field identification & locations

Identify in the field by its ability to scratch glass, its lack of cleavage (it breaks into irregular, sharp shards), and its opaque white 'cloudy' look. It is found globally, common in mountain ranges and stream beds. Collectors should look for distinct crystal faces rather than tumbled river rocks for higher value.