mineral

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: 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: White to translucent
Luster: Vitreous to greasy

Identified June 30, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: White to translucent; Luster: Vitreous to greasy; 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. This specific specimen has been smoothed and rounded by water erosion in a river or beach environment.

Uses & applications

Used in landscaping, glass making, electronics (piezoelectric properties), and as decorative gravel. Lower grade for collecting but significant in industrial abrasives.

Geological facts

The milky white color is caused by microscopic inclusions of gas or liquid trapped during the crystal's growth. It is one of the most abundant minerals in the Earth's crust.

Field identification & locations

Identify in the field by its hardness (cannot be scratched by a steel knife) and its white, waxy appearance. Commonly found in riverbeds, glacial deposits, and mountain outcrops worldwide.