sedimentary

Red sandstone fragment

Quartz-rich sandstone, commonly ferruginous sandstone

AI-generated identification · may be incorrect

Typically 6–7 Mohs hardness, reddish-brown from iron-oxide coatings or cement, dull to slightly sparkly, and composed of sand-sized grains weakly to moderately cemented together. It has no consistent crystal structure or cleavage and commonly feels gritty.

Identified August 18, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms when quartz-rich sand is compacted and cemented, often in river, desert, shoreline, or floodplain settings; the red color reflects oxidation of iron minerals. Its age cannot be determined from the image and may range from Precambrian to recent geological formations.

Uses & applications

Used as building stone, paving, aggregate, and occasionally decorative or landscaping material; ordinary fragments have little jewelry value.

Geological facts

The visible granular texture and rusty-red coloration are characteristic of iron-bearing sandstone, though the image is not sufficient for a precise formation or locality identification.

Field identification & locations

Identify it by rubbing the gritty surface, examining visible sand grains, and testing dilute hydrochloric acid for absent or weak fizz; a glass-scratch test may work because quartz grains are hard. Common worldwide, especially in red-bed formations and desert regions.