sedimentary

Weathered iron-rich sandstone or lateritic concretion

Ferruginous sandstone; commonly quartz (SiO₂) cemented or stained by iron oxides/hydroxides such as hematite (Fe₂O₃) and goethite (FeO(OH))

AI-generated identification · may be incorrect

Brown to reddish-brown, dull earthy luster, rounded and strongly weathered, with a fine granular/porous texture. Typical hardness is about 5–7 where quartz-rich, but softer or crumbly in iron-rich porous zones; no obvious cleavage or crystal faces.

Identified September 19, 2026More sedimentary →

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At a glance

Common name: Weathered iron-rich sandstone or lateritic concretion
Scientific name: Ferruginous sandstone; commonly quartz (SiO₂) cemented or stained by iron oxides/hydroxides such as hematite (Fe₂O₃) and goethite (FeO(OH))
Category: sedimentary
Identified: September 19, 2026
Method: Standard

AI Estimated Value

About $1–$10 as a common hand specimen; generally under $20 unless locality, texture, or provenance is documented.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Likely formed from sand compacted and cemented by silica and iron minerals, then rounded by stream or surface weathering. The photograph cannot establish a precise geological age; ferruginous sandstones and lateritic nodules occur from ancient to modern deposits.

Uses & applications

Used locally as building or paving stone and as a source of silica or iron-bearing material, though this small specimen has mainly educational or decorative value.

Geological facts

The dark reddish color reflects oxidized iron. Rounded shapes can develop through erosion, while irregular iron cement produces the mottled surface.

Field identification & locations

Look for gritty quartz grains, reddish-brown streak or powder, and greater density than ordinary soil concretions; a streak test, hardness test, and dilute acid test help distinguish it from limestone. Common in tropical laterites, desert gravels, riverbeds, and iron-rich sedimentary formations.