metamorphic

River Pebble (Quartzite/Chert)

Quartzite with inclusions (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 (Mohs scale), Color: Creamy white with tan/grey patterns, Luster: Waxy to vitreous when wet/polished, Structure: Microcrystalline, Cleavage: None/Conchoidal fracture

Identified April 15, 2026More metamorphic →

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Physical properties

Hardness: 7 (Mohs scale), Color: Creamy white with tan/grey patterns, Luster: Waxy to vitreous when wet/polished, Structure: Microcrystalline, Cleavage: None/Conchoidal fracture

Formation & geological history

Formed from the metamorphism of quartz-rich sandstone or through silica precipitation. Smooth shape is the result of mechanical weathering in an aquatic environment over years or decades.

Uses & applications

Landscape decoration, aquarium gravel, tumbling for hobbyists, and industrial abrasive.

Geological facts

The rounded shape is caused by saltation, where the rock bounces along a riverbed, grinding its edges down. These are among the most common geological finds worldwide.

Field identification & locations

Identify by its hardness (will scratch glass), smooth surface, and lack of visible individual grains. Found in riverbeds, glacial deposits, and beaches.