mineral

Milky Quartz

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: White, often translucent to opaque; Luster: Vitreous to greasy; Crystal Structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: White, often translucent to opaque
Luster: Vitreous to greasy

Identified June 6, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: White, often translucent 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 hydrothermal veins or within pegmatites. The milky appearance is caused by tiny inclusions of gas or liquid trapped during crystal growth.

Uses & applications

Used in glass manufacturing, as an abrasive, in the semiconductor industry, as decorative landscape stone, and occasionally in jewelry for cabochons.

Geological facts

Milky quartz is the most common variety of crystalline quartz. Historically, it was used by many cultures for stone tools when flint was unavailable, despite its difficult fracturing properties.

Field identification & locations

Identify in the field by its hardness (scratches glass), lack of cleavage, and white 'milky' appearance. It is found globally, particularly in mountainous regions and riverbeds as eroded pebbles.