mineral

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 on Mohs scale; Color: Cloudy white to pale tan; 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 pale tan
Luster: Vitreous to greasy

Identified March 14, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed from silica-rich hydrothermal fluids in veins or as a primary constituent of igneous rocks. This specific specimen is water-worn, indicating it was eroded from its source and tumbled in a river or coastal environment over thousands of years.

Uses & applications

Used industrially as a source of silicon, as an abrasive, and in glassmaking. In this rounded form, it is popular for landscaping, decorative garden stones, and as a 'worry stone' for collectors.

Geological facts

Milky quartz gets its cloudy appearance from microscopic inclusions of gas or liquid trapped during the crystal's growth. It is the most common variety of crystalline quartz found on Earth's surface.

Field identification & locations

Identify in the field by its ability to scratch glass, its lack of cleavage, and the smooth, rounded 'river rock' texture. It is ubiquitous in gravel bars, beaches, and glacial till globally.