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 26, 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

Formed in hydrothermal veins or as a primary constituent in igneous rocks like granite. The white color is caused by microscopic liquid or gas inclusions trapped during crystal growth.

Uses & applications

Used widely in glassmaking, abrasives, silicon production, electronics (oscillator crystals), and as decorative landscaping stones.

Geological facts

Milky quartz is the most common variety of crystalline quartz. It is often found in massive form rather than distinct crystal points.

Field identification & locations

Identify by its hardness (scratches glass), lack of cleavage, and characteristic opaque white appearance. Often found in riverbeds as rounded cobbles or protruding from darker host rocks.