mineral

Milky Quartz

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 March 23, 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 cooling of silica-rich magma or from hydrothermal veins. The milky appearance is caused by microscopic inclusions of gas or liquid trapped during crystal growth. They are found across all geological ages, from Precambrian to Cenozoic.

Uses & applications

Used in glassmaking, as an abrasive, in the production of silicon for electronics, and widely as a semi-precious gemstone in jewelry or for decorative tumbling.

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, making it a key indicator for prospectors.

Field identification & locations

Identify in the field by its hardness (will scratch glass), cloudy white appearance, and lack of cleavage. Common in many environments, particularly in river beds, beaches, and mountain veins. Collectors should look for unique banding or host-rock attachments.