mineral

Quartz Pebble

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale); Color: White, tan, or milky; Luster: Vitreous to waxy (especially when water-worn); Crystal Structure: Hexagonal/Trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 (Mohs scale)
Color: White, tan, or milky
Luster: Vitreous to waxy (especially when water-worn)

Identified March 14, 2026More mineral →

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Physical properties

Formation & geological history

Formed from hydrothermal veins or as a primary constituent of granitic rocks. This specific specimen is a 'river rock' or 'alluvial pebble,' meaning it has been mechanically weathered and rounded by water transport over decades or centuries.

Uses & applications

Used in landscaping, as tumbling rough for lapidary hobbies, and on an industrial scale for glass making and silicon production.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Specimens like this often show 'impact scars' (half-moon fractures) caused by colliding with other rocks in high-energy river or beach environments.

Field identification & locations

Identify in the field by its hardness (it should easily scratch glass) and lack of visible mineral grains. Commonly found in riverbeds, glacial till, and beaches globally.