mineral

Milky Quartz Pebble

Silicon Dioxide (SiO2)

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

Hardness: 7 on Mohs scale
Color: Milky white to opaque
Luster: Vitreous to greasy

Identified June 10, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed in hydrothermal veins or as a constituent of igneous and metamorphic rocks. This specific specimen is water-worn, indicating a secondary fluvial or coastal environment where it was rounded by erosion.

Uses & applications

Used in glassmaking, electronics (piezoelectric properties), abrasives, and as decorative gravel or landscaping stone. Common in beginner mineral collections.

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 by its hardness (scratches glass), lack of cleavage, and white opaque color. Frequently found in riverbeds, beaches, and glacial till globally.