sedimentary/metamorphic

River Pebble (Quartzite/Siltstone mixture)

Silicon Dioxide (SiO2) mixture with varied clastic minerals

Hardness: 6-7 (Mohs scale); Color: Tan/Brown/Beige; Luster: Dull/Waxy; Structure: Microcrystalline; Cleavage: None/Conchoidal fracture; Specific Gravity: 2.6-2.7

Hardness: 6-7 (Mohs scale)
Color: Tan/Brown/Beige
Luster: Dull/Waxy

Identified April 12, 2026More sedimentary/metamorphic →

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Physical properties

Hardness: 6-7 (Mohs scale); Color: Tan/Brown/Beige; Luster: Dull/Waxy; Structure: Microcrystalline; Cleavage: None/Conchoidal fracture; Specific Gravity: 2.6-2.7

Formation & geological history

Formed through the weathering and erosion of pre-existing rock masses, typically transported and rounded by water action in a river or stream bed over thousands of years.

Uses & applications

Commonly used in landscaping, road base, concrete aggregate, and as 'pocket stones' for casual collectors.

Geological facts

River rocks get their smooth, rounded shape through a process called 'saltation,' where stones are bounced along a riverbed, grinding off sharp edges.

Field identification & locations

Identify by its smooth, water-worn outer surface and uniform tan color. Found globally in alluvial deposits and ancient riverbeds.

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