mineral

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 (Mohs scale), Color: Opaque white to translucent milky, Luster: Vitreous to waxy when water-worn, Crystal Structure: Trigonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Identified June 6, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale), Color: Opaque white to translucent milky, Luster: Vitreous to waxy when water-worn, Crystal Structure: Trigonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65

Formation & geological history

Formed from hydrothermal veins or as a primary constituent of granitic rocks. This specific specimen has been Rounded by fluvial or glacial action in riverbeds or coastal environments. Quartz is chemically stable and persists through multiple geological cycles.

Uses & applications

Used as an abrasive, in glassmaking, and in landscaping. Polished pebbles are frequently used in decorative vases, aquariums, and as pocket stones for collectors. High-purity quartz is essential for semiconductor manufacturing.

Geological facts

The milky appearance is caused by tiny inclusions of gas and/or liquid trapped during crystal growth. Quartz is one of the most abundant minerals in the Earth's crust and is highly resistant to chemical weathering.

Field identification & locations

Identify by its hardness (it will scratch glass), lack of cleavage, and characteristic white opacity. It is commonly found in river gravels, on beaches, and as vein material in mountains. Collectors look for smooth, well-rounded shapes or interesting internal patterns.