sedimentary

Weathered iron-rich rock, likely shale or slate

Probably ferruginous shale (iron-oxide-stained mudstone); exact identification requires testing

AI-generated identification · may be incorrect

Fine-grained, dark gray to brown, dull earthy luster with rusty yellow-orange iron-oxide staining and thin planar cleavage/bedding; likely Mohs hardness about 2–4. No visible crystals or glassy texture.

Identified September 15, 2026More sedimentary →

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At a glance

Common name: Weathered iron-rich rock, likely shale or slate
Scientific name: Probably ferruginous shale (iron-oxide-stained mudstone); exact identification requires testing
Category: sedimentary
Identified: September 15, 2026
Method: Standard

AI Estimated Value

Typically $0–$10 as an ordinary fragment; attractive specimens or locality-labeled pieces may sell for about $10–$30.

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 from compacted, lithified clay-rich sediment, later fractured and oxidized during weathering; commonly Paleozoic to Mesozoic in age depending on locality.

Uses & applications

Usually low commercial value; may be used locally as fill, landscaping stone, or aggregate if sound, but is generally unsuitable for high-quality construction because it splits and weathers readily.

Geological facts

Rust-colored patches are commonly limonite/goethite produced by oxidation of pyrite or other iron-bearing minerals. The flat break surfaces indicate sedimentary layering or low-grade metamorphic cleavage.

Field identification & locations

Identify by fine grain, easy splitting along planes, earthy dull surface, and orange-brown weathering stains; a streak, acid, hardness, and locality would distinguish shale from slate or iron-rich volcanic rock. Common in sedimentary basins worldwide.