mineral

Milky Quartz Pebble

Crystalline Silicon Dioxide (SiO2)

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

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

Identified March 6, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed from hydrothermal solutions or cooling magma where fluid inclusions of gas or liquid create the milky opacity. This specific specimen has been water-worn and rounded by fluvial or coastal transport over geologic time.

Uses & applications

Used in glassmaking, as an abrasive, in electronics (piezoelectric properties), landscaping, and as decorative river stones or pocket stones.

Geological facts

The milky appearance is caused by tiny bubbles of gas or liquid trapped during the crystal's formation. It is one of the most abundant minerals on Earth's crust.

Field identification & locations

Identify in the field by its ability to scratch glass and its lack of cleavage. Commonly found in riverbeds, beaches, and weathered outcrops globally. Collectors look for unique shapes or clarity.

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