sedimentary

Weathered iron-rich sandstone or laterite

Ferruginous sandstone; chiefly quartz (SiO₂) cemented by iron oxides/hydroxides

AI-generated identification · may be incorrect

Hardness about 5–7; reddish-brown, tan, and ochre coloration with earthy to dull luster, granular texture, and no obvious cleavage. The color suggests hematite/goethite staining; exact identification requires a fresh surface, acid test, and/or microscopy.

Identified August 28, 2026More sedimentary →

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Physical properties

Formation & geological history

Likely formed when quartz-rich sediment was compacted and cemented by iron-bearing groundwater, or as a strongly weathered lateritic crust. Such materials range from Precambrian to Recent and occur in terrestrial sedimentary and tropical weathering environments.

Uses & applications

Common ferruginous sandstone is used locally as building stone, aggregate, and occasionally pigment source; attractive pieces are collected as cabinet specimens. It has little gemstone value unless unusually patterned or polished.

Geological facts

Iron oxides can produce intense red, orange, and brown colors and may make the rock weakly magnetic if magnetite is present. Surface weathering can obscure the original sedimentary texture.

Field identification & locations

Look for gritty quartz grains, rusty streaks, and layered or clastic texture; it should not fizz strongly with dilute hydrochloric acid. Common in weathered terrains and sandstone formations worldwide.