sedimentary

Weathered ironstone pebble (likely ferruginous concretion)

Iron-oxide-cemented concretion, commonly hematite (Fe₂O₃) and/or goethite (FeO(OH))

AI-generated identification · may be incorrect

Small, rounded, mottled brown pebble with a rusty outer surface and a darker, rounded central feature; likely opaque with earthy to dull luster. Hardness and composition cannot be determined reliably from the photograph.

Identified September 29, 2026More sedimentary →

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At a glance

Common name: Weathered ironstone pebble (likely ferruginous concretion)
Scientific name: Iron-oxide-cemented concretion, commonly hematite (Fe₂O₃) and/or goethite (FeO(OH))
Category: sedimentary
Identified: September 29, 2026
Method: Standard

AI Estimated Value

About $1–$10 for a small, common pebble; higher value would require distinctive patterning 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

Iron-rich minerals cemented grains or accumulated around a nucleus during sediment formation or weathering; such concretions form in many ages and environments.

Uses & applications

Usually collected as a curiosity; ironstone can also serve as iron ore where iron concentrations are high. This specimen appears too small for industrial use.

Geological facts

Concretions commonly develop rounded shapes as iron oxides precipitate from groundwater, sometimes producing concentric or spot-like patterns.

Field identification & locations

Look for a dense, rusty-brown pebble that may leave a reddish-brown streak; a hardness or streak test would help distinguish iron oxides from other materials. Ironstone pebbles occur worldwide in soils, river gravels, and sedimentary formations.