mineral

White Quartz Pebble (Milky Quartz)

Silicon Dioxide (SiO2)

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

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

Identified March 24, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed from silica-rich hydrothermal solutions cooling in tectonic veins or as a primary constituent of pegmatites. The milky appearance is caused by microscopic fluid inclusions of gas or liquid trapped during crystal growth. Can be millions to billions of years old.

Uses & applications

Used in glass manufacturing, electronics (due to piezoelectric properties), construction aggregates, and as decorative landscape gravel or semi-precious tumbled stones.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Milky quartz signifies that 'bubbles' or fluid inclusions were present during its formation, distinguishing it from clear rock crystal.

Field identification & locations

Identify in the field by its inability to be scratched by a steel knife, its lack of cleavage, and its waxy/vitreous luster. Commonly found in riverbeds, beaches, and mountain trails globally.

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