mineral

Milky Quartz Pebble

Silicon Dioxide (SiO2)

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

Hardness: 7 on Mohs scale
Color: Milky white with brownish iron staining
Luster: Vitreous to greasy

Identified May 19, 2026More mineral →

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Physical properties

Formation & geological history

Formed via hydrothermal activity where silica-rich fluids cool in veins or as a major constituent of igneous rocks like granite. This specific specimen has been smoothed and rounded by fluvial (river) or glacial erosion.

Uses & applications

Industrial use in glassmaking and abrasives; small pebbles are often used as landscaping gravel or decorative aquarium stones.

Geological facts

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

Field identification & locations

Identified in the field by its hardness (it will scratch glass), its white color, and the lack of cleavage planes. Found globally in riverbeds, beaches, and soil.