sedimentary
River Stones (Quartzite and Sandstone)
Quartzite / Sedimentary Rock (SiO2 dominant)
Hardness: 6-7 on Mohs scale. Colors: tan, yellow-brown, grey. Luster: dull to vitreous. Texture: smooth to gritty, weathered by water. Structure: microcrystalline or granular.
- Hardness
- 6-7 on Mohs scale
- Luster
- dull to vitreous
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Physical properties
Hardness: 6-7 on Mohs scale. Colors: tan, yellow-brown, grey. Luster: dull to vitreous. Texture: smooth to gritty, weathered by water. Structure: microcrystalline or granular.
Formation & geological history
These are river-tumbled stones formed through millions of years of water erosion. They likely originated as sedimentary sandstone or metamorphic quartzite that was transported by high-energy water environments like rivers or glacial runoff.
Uses & applications
Landscaping, decorative garden filler, basic construction aggregate, and stone painting hobbies. Rougher pieces are used for road base or drainage.
Geological facts
The smooth, rounded edges are a result of 'saltation' and abrasion as rocks crash together in a riverbed. These stones can travel hundreds of miles from their original mountain source, becoming smoother the further they go.
Field identification & locations
Identify in the field by their rounded, water-worn shapes and various earth-tone layers. They are common in riverbeds, glacial moraines, and shorelines. Look for mineral veins (like the dark line in the center stone) which indicate secondary mineral deposits.
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