mineral

Milky Quartz Pebble

Silicon Dioxide (SiO2)

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

Hardness: 7 on Mohs scale
Color: Opaque white to slightly tan
Luster: Vitreous to greasy

Identified July 19, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed from silica-rich hydrothermal solutions or as a primary constituent in igneous rocks like granite. This specific specimen shows water-worn rounding, likely from a river or beach environment.

Uses & applications

Used in the production of glass, ceramics, and abrasives. Also used in construction aggregate and as a decorative stone in landscaping or low-cost jewelry.

Geological facts

Milky quartz gets its cloudy appearance from tiny fluid inclusions of gas or liquid trapped during crystal growth. It is the most common variety of crystalline quartz found on Earth.

Field identification & locations

Identify by its ability to scratch glass (hardness 7) and its lack of cleavage. It is ubiquitous in gravel pits, mountain streams, and along shorelines worldwide.