metamorphic

River Pebble (Quartzite/Sandstone mix)

Quartzite (primarily SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: Tan to light pinkish-brown; Luster: Dull to waxy; Texture: Fine-grained, smooth, and rounded due to water erosion; Cleavage: None (conchoidal fracture).

Hardness: 7 on Mohs scale
Color: Tan to light pinkish-brown
Luster: Dull to waxy

Identified April 14, 2026More metamorphic →

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Physical properties

Hardness: 7 on Mohs scale; Color: Tan to light pinkish-brown; Luster: Dull to waxy; Texture: Fine-grained, smooth, and rounded due to water erosion; Cleavage: None (conchoidal fracture).

Formation & geological history

Originates from sandstone that has undergone high heat and pressure (metamorphism). The smooth, ovoid shape is formed through long-term saltation and abrasion in a riverbed or coastal environment.

Uses & applications

Commonly used in landscaping, as decorative gravel, in construction as an aggregate, or as a pocket stone for collectors.

Geological facts

Quartzite is one of the most durable rocks on the Earth's surface. While it starts as sand, the individual grains fuse so tightly that the rock will break through the grains rather than around them.