mineral

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Hardness: 7 (Mohs scale). Color: Tans, yellows, and creams (likely stained by iron oxides). Luster: Vitreous to waxy. Crystal structure: Trigonal (often massive in pebbles). Cleavage: None (conchoidal fracture). Specific gravity: 2.65.

Hardness: 7 (Mohs scale)
Color: Tans, yellows, and creams (likely stained by iron oxides)
Luster: Vitreous to waxy

Identified May 21, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich hydrothermal fluids or within igneous and metamorphic rocks. This specific specimen has been eroded and smoothed through fluvial processes (water transport in rivers) over thousands of years.

Uses & applications

Used widely in manufacturing glass, ceramics, and abrasives. Tumbled specimens are used in landscaping, interior design, and as pocket stones for collectors.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. It is piezoelectric, meaning it can generate an electric charge in response to mechanical stress.

Field identification & locations

Identify by its hardness (it will scratch glass and metal files) and its lack of cleavage. Common in riverbeds and on beaches worldwide. Collectors should look for translucency and smooth texture.