sedimentary

Ironstone concretion (probable hematite–goethite-rich ironstone)

Iron oxide/hydroxide concretion; chiefly hematite (Fe₂O₃) and goethite (FeO(OH)), with possible magnetite and quartz

AI-generated identification · may be incorrect

Hardness about 5–6.5 Mohs; dark brown to rusty red, earthy to submetallic luster, dense and fine-grained, with rounded weathering pits and little or no cleavage. Its heavy feel and possible weak magnetism support an iron-rich composition.

Identified August 8, 2026More sedimentary →

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At a glance

Common name: Ironstone concretion (probable hematite–goethite-rich ironstone)
Scientific name: Iron oxide/hydroxide concretion; chiefly hematite (Fe₂O₃) and goethite (FeO(OH)), with possible magnetite and quartz
Category: sedimentary
Identified: August 8, 2026
Method: Standard

AI Estimated Value

Typically $5–$30 for a common hand specimen; $30–$100+ for unusually sculptural, dense, or polished pieces.

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

Formed when iron-bearing minerals precipitated and cemented sediment around nuclei, commonly in ancient river, lake, or shallow marine deposits; later weathering concentrated the iron. Exact geological age cannot be determined from the image.

Uses & applications

Used historically as iron ore when sufficiently rich; otherwise it is mainly a common field specimen, landscaping stone, or lapidary material. It has limited jewelry value unless polished and attractively patterned.

Geological facts

The porous, knobby surface is typical of ironstone concretions or weathered iron-rich nodules, not necessarily a meteorite. A reddish-brown streak and high density are characteristic of hematite/goethite.

Field identification & locations

Common in sedimentary terrains and gravel bars worldwide, including Australia, North America, India, and Africa. Test with an unglazed porcelain streak plate, magnet, and specific-gravity comparison; identification remains approximate without testing.