mineral

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: white to off-white, opaque; Luster: waxy to vitreous; Crystal structure: Trigonal; Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: white to off-white, opaque
Luster: waxy to vitreous

Identified July 1, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: white to off-white, opaque; Luster: waxy to vitreous; Crystal structure: Trigonal; Cleavage: None/Conchoidal fracture; Specific Gravity: 2.65

Formation & geological history

Formed from silica-rich hydrothermal fluids cooling in veins or as a major component of igneous rocks like granite. This specific specimen has been river-worn or tumbled, giving it a rounded, smooth shape.

Uses & applications

Used in landscaping, as a source for silicon in glass making, and as a common collectible for beginners.

Geological facts

Milky quartz gets its cloudy appearance from tiny 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 by its hardness (will scratch glass), lack of cleavage, and translucent to opaque white appearance. Very common in riverbeds, glacial deposits, and mountain regions worldwide.