mineral

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

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

Hardness: 7 on Mohs scale
Color: Opaque white (milky)
Luster: Vitreous to greasy

Identified May 29, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed through hydrothermal processes or igneous crystallization from silica-rich magma/fluids. This specimen appears water-worn, smoothed by alluvial or fluvial action.

Uses & applications

Used in construction as aggregate, in glassmaking, as a source of silicon for electronics, and occasionally as decorative gravel or tumbled stones for hobbyists.

Geological facts

The milky appearance is caused by microscopic inclusions of gas or liquid trapped during crystal growth. Quartz is the second most abundant mineral in Earth's continental crust.

Field identification & locations

Identify in the field by its hardness (will scratch glass), white color, and lack of cleavage. Commonly found in river beds, beaches, and soil near quartz veins.