sedimentary

Ironstone (iron-rich sandstone or concretion)

Ferruginous sandstone, cemented by iron oxides/hydroxides such as hematite (Fe₂O₃) and goethite (FeO(OH))

AI-generated identification · may be incorrect

Opaque, rusty reddish-brown, with a wet earthy to slightly metallic sheen and rough, fine-grained surface. Hardness and density vary with composition; the image does not reveal diagnostic crystals or cleavage.

Identified October 11, 2026More sedimentary →

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At a glance

Common name: Ironstone (iron-rich sandstone or concretion)
Scientific name: Ferruginous sandstone, cemented by iron oxides/hydroxides such as hematite (Fe₂O₃) and goethite (FeO(OH))
Category: sedimentary
Identified: October 11, 2026
Method: Standard

AI Estimated Value

About $2–$20 for a common hand specimen; higher prices require unusual form, locality, or verified composition.

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 when iron-rich groundwater cemented sediment or precipitated iron oxides; such ironstones occur in many geological periods. Exact age and formation cannot be determined from appearance alone.

Uses & applications

Commonly collected as a geological specimen; iron-rich varieties have historically been mined as iron ore, though this piece’s grade is unknown.

Geological facts

Iron oxides produce the characteristic red-brown color, and fresh surfaces may look darker when wet.

Field identification & locations

Look for high density, rusty streaks, and iron-oxide cement; distinguish it from slag by its natural sedimentary texture. Found in sedimentary terrains worldwide.