sedimentary

Weathered iron-rich rock, possibly limonite-bearing sandstone or ironstone

Limonite/goethite-rich ferruginous sandstone; composition uncertain from the photograph

AI-generated identification · may be incorrect

Brown-gold, earthy to slightly granular surface with uneven fracture and weak sparkle from fine mineral grains; likely Mohs hardness about 4–6, opaque, with dull to submetallic luster and no obvious cleavage. Exact density and mineralogy require testing.

Identified September 15, 2026More sedimentary →

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At a glance

Common name: Weathered iron-rich rock, possibly limonite-bearing sandstone or ironstone
Scientific name: Limonite/goethite-rich ferruginous sandstone; composition uncertain from the photograph
Category: sedimentary
Identified: September 15, 2026
Method: Standard

AI Estimated Value

About $1–$10 as an ordinary specimen; potentially $10–$50 if analysis shows attractive crystallized goethite or significant iron-ore quality.

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-bearing groundwater cemented or replaced sediment, producing goethite/limonite and possibly hematite; age and geological setting cannot be determined visually. Such rocks commonly form in weathering zones and sedimentary iron deposits.

Uses & applications

Usually collected as a mineral specimen or used locally as iron ore/aggregate when sufficiently rich; this example has no evident gem or ornamental value.

Geological facts

Limonite is a mixture of hydrated iron oxides rather than a single precisely defined mineral, while goethite is a distinct iron oxyhydroxide. The yellow-brown streak typical of limonite/goethite differs from hematite’s red-brown streak.

Field identification & locations

Common in iron-rich soils, laterites, sedimentary iron formations, and oxidized ore zones worldwide. Check streak on unglazed porcelain, magnetism, hardness, and acid reaction; a laboratory analysis is needed for confident identification.