sedimentary

River Pebble (Quartzite / Sandstone)

SiO2 (Quartz-rich sedimentary/metamorphic rock)

AI-generated identification · may be incorrect

Hardness: 6-7 on Mohs scale. Color: Tan, brown, reddish-brown. Luster: Dull to sub-vitreous. Texture: Smooth, water-worn, fine-grained. Specific Gravity: ~2.65.

Hardness: 6-7 on Mohs scale
Color: Tan, brown, reddish-brown
Luster: Dull to sub-vitreous

Identified July 23, 2026More sedimentary →

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Physical properties

Hardness: 6-7 on Mohs scale. Color: Tan, brown, reddish-brown. Luster: Dull to sub-vitreous. Texture: Smooth, water-worn, fine-grained. Specific Gravity: ~2.65.

Formation & geological history

Formed through the erosion and deposition of silica-rich sediments, subsequently rounded and smoothed over time by water action in streams, rivers, or beach environments.

Uses & applications

Used in landscaping, decorative stone arrangements, construction aggregates, lapidary polishing practice, and casual rock collecting.

Geological facts

Water-worn pebbles can travel hundreds of miles along riverbeds over thousands of years, gaining their distinctive smooth, elongated shape from continuous friction against other stones.

Field identification & locations

Identify by its extremely smooth, rounded shape with no sharp edges and hard, fine-grained silica texture. Commonly found in riverbeds, gravel pits, lakeshores, and ocean beaches worldwide.