mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

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

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

Identified March 24, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed from the cooling of magma or by hydrothermal activity deep in the Earth's crust. As silica-rich fluids cool in veins or cavities, quartz crystals precipitate. This specific specimen appears to be a water-worn or weathered pebble containing a quartz vein.

Uses & applications

Used in industry for glassmaking, abrasives, and electronics (due to piezoelectric properties). Often used in construction as aggregate. Milky quartz is also popular for landscaping and as minor decorative stones.

Geological facts

Milky quartz gets its white color from microscopic inclusions of gas and liquid trapped during crystal growth millions of years ago. It is the most common variety of crystalline quartz found on Earth.

Field identification & locations

Identify by its ability to scratch glass and its lack of cleavage. It is commonly found in riverbeds, glacial deposits, and mountain ranges globally. Beginners should look for its waxy luster when wet and its distinctive white streak through host rocks.