sedimentary

River Pebble (Quartz-rich)

Silicon Dioxide (SiO2) with impurities

AI-generated identification · may be incorrect

Hardness: 7 (Mohs); Color: Tan, beige, off-white; Luster: Dull to sub-vitreous; Structure: Microcrystalline/Massive; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 (Mohs)
Color: Tan, beige, off-white
Luster: Dull to sub-vitreous

Identified July 15, 2026More sedimentary →

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Physical properties

Hardness: 7 (Mohs); Color: Tan, beige, off-white; Luster: Dull to sub-vitreous; Structure: Microcrystalline/Massive; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Formation & geological history

Formed through the weathering and erosion of larger rock masses, typically igneous or metamorphic. These rounded shapes are created by long-term transport in riverbeds or coastal environments where water action smooths the surface.

Uses & applications

Primarily used in construction as aggregate, landscaping, decorative garden stones, and occasionally for rock tumbling by hobbyists.

Geological facts

River pebbles are natural time capsules that can be millions of years old, often originating from mountain ranges hundreds of miles away from where they are eventually found.

Field identification & locations

Identify by its rounded, smooth texture and high hardness (will scratch glass). Commonly found in stream beds, beaches, and glacial deposits. Look for uniform color and lack of visible grains.