mineral

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 on the Mohs scale; Color: Milky white to translucent tan; Luster: Vitreous (glassy) to waxy when water-worn; Crystal structure: Trigonal (often appears massive in pebbles); Cleavage: None (conchoidal fracture); Specific gravity: 2.65

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

Identified March 19, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the cooling of silica-rich magma or from hydrothermal veins. This specific specimen is a 'river rock' or 'alluvial pebble' that has been smoothed and rounded by the mechanical action of water and abrasive sediments over hundreds to thousands of years.

Uses & applications

Used industrially for making glass and electronics (silicon source), as an abrasive, and in construction as an aggregate. Tumbled versions like this are popular for landscaping, home decor, and beginner rock collections.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Its name comes from the Greek word 'krustallos', meaning ice, because ancient philosophers believed it was ice frozen so hard it could never melt.

Field identification & locations

Identify in the field by its hardness (it can scratch glass and steel), lack of cleavage, and smooth, rounded surface indicating transport by water. It is ubiquitous in riverbeds, beaches, and glacial till worldwide.