mineral

Weathered iron-rich rock (likely ironstone or limonite-bearing concretion)

Goethite–hematite–limonite mixture, commonly written FeO(OH) ± Fe₂O₃

AI-generated identification · may be incorrect

Brown to dark reddish-brown, earthy to submetallic luster, fine-grained and irregular; Mohs hardness about 4–6, with no visible cleavage. The pale gray coating may be weathering residue or a mineral crust.

Identified September 5, 2026More mineral →

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At a glance

Common name: Weathered iron-rich rock (likely ironstone or limonite-bearing concretion)
Scientific name: Goethite–hematite–limonite mixture, commonly written FeO(OH) ± Fe₂O₃
Category: mineral
Identified: September 5, 2026
Method: Standard

AI Estimated Value

About $1–$10 for a common rough piece; $20–$100+ for aesthetically botryoidal or well-documented collector specimens.

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

Forms through oxidation and hydration of iron-bearing minerals in soils, sedimentary rocks, hydrothermal veins, or weathering zones; typically young-to-ancient secondary material rather than a single age-diagnostic rock.

Uses & applications

Used historically as iron ore and natural brown/red pigment; ordinary specimens have little industrial or jewelry value, though attractive botryoidal goethite can be collectible.

Geological facts

Goethite and limonite commonly produce rusty streaks and earthy textures, while hematite gives deeper red-brown coloration. Exact identification requires streak, density, and mineralogical testing.

Field identification & locations

Likely found in weathered outcrops, stream gravels, laterite, and iron-rich sedimentary deposits worldwide. A reddish-brown streak on unglazed porcelain, high density, and attraction only if magnetite is present help distinguish it from ordinary brown stone.