mineral

Milky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Opaque white; Luster: Vitreous to greasy; Crystal Structure: Trigonal (hexagonal system); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

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

Identified May 21, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Opaque white; Luster: Vitreous to greasy; Crystal Structure: Trigonal (hexagonal system); Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Forms during the final stages of hydrothermal mineral crystallization in veins or pegmatites. The white color is caused by microscopic fluid inclusions of gas or liquid trapped during crystal growth.

Uses & applications

Used as a gemstone (cabochons, carvings), in decorative landscaping, and as a source of silica in glassmaking and electronics.

Geological facts

Milky quartz is the most common variety of crystalline quartz. While it lacks the transparency of rock crystal, it is highly durable and can survive long periods of erosion, which is why it is often found as rounded river pebbles.

Field identification & locations

Identified in the field by its white color, hardness (it will scratch glass), and lack of cleavage. It is ubiquitous in mountainous regions and stream beds worldwide. Collectors often seek pieces with unique shapes or those containing inclusions of other minerals like gold.