sedimentary
Sandstone (Quartzite-rich River Cobble)
Clastic sedimentary rock (primarily SiO2)
Hardness: 6-7 Mohs; Color: Tan, beige, or light brown; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Cleavage: None; Specific gravity: 2.3–2.4
- Hardness
- 6-7 Mohs
- Color
- Tan, beige, or light brown
- Luster
- Dull/Earthy
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Physical properties
Hardness: 6-7 Mohs; Color: Tan, beige, or light brown; Luster: Dull/Earthy; Crystal structure: Granular/Clastic; Cleavage: None; Specific gravity: 2.3–2.4
Formation & geological history
Formed from the accumulation and cementation of mineral particles (sand); this specific specimen has been rounded and polished through fluvial processes (water erosion in a river or stream) over thousands to millions of years.
Uses & applications
Used primarily as decorative landscaping stone, in construction aggregates, and occasionally as a primitive tool (grinding stone/hand axe) by early humans.
Geological facts
Sandstone contains about 20-25% of the world's groundwater. The rounded shape indicates a long journey through a body of water, smoothing away all sharp edges of the original parent rock.
Field identification & locations
Identify in the field by its gritty texture (feels like sandpaper) and rounded, water-worn exterior. Found globally in riverbeds, glacial deposits, and beaches.
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