mineral

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 on the Mohs scale; Color: Milky white to translucent; Luster: Vitreous to waxy (especially when water-worn); Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on the Mohs scale
Color: Milky white to translucent
Luster: Vitreous to waxy (especially when water-worn)

Identified March 20, 2026More mineral →

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Physical properties

Formation & geological history

Formed from the crystallization of silica-rich magma or from hydrothermal veins. This specific specimen is a 'river rock' or 'beach pebble,' meaning it was weathered from its parent rock and shaped by the mechanical erosion of water over hundreds to thousands of years.

Uses & applications

Used industrially in glassmaking and abrasives. As a rounded pebble, it is commonly used in landscaping, decorative stone masonry, and for tumbling or lapidary practice. High-purity quartz is also essential for electronics and quartz watches.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Rounded white quartz pebbles like this one are often referred to as 'bull quartz' in the field when they lack visible crystal faces. It is chemically very stable, which is why it often survives the erosion process that destroys other minerals.

Field identification & locations

Identify in the field by its hardness (it will scratch glass and steel knife blades), its lack of cleavage, and its typical 'waxy' or 'salty' appearance when wet. It is found globally in riverbeds, beaches, and glacial deposits.