mineral

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Opaque white; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

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

Identified June 8, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Opaque white; Luster: Vitreous to waxy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Formation & geological history

Formed through the crystallization of silica-rich hydrothermal fluids in veins or as a primary constituent in igneous rocks like granite. This specific specimen has been tumbled and rounded by water action in a river or beach environment.

Uses & applications

Used as an abrasive, in glass manufacturing, electronics (due to piezoelectric properties), and as decorative landscaping stone or tumbled pocket stones.

Geological facts

The 'milky' appearance is caused by tiny inclusions of gas or liquid trapped during the crystal's growth. It is the most common variety of crystalline quartz found on Earth's crust.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), its white opaque color, and lack of cleavage. Often found in riverbeds, glacial till, and gravel pits.