sedimentary

Brown shale or mudstone fragment

Likely fissile claystone/shale, composed mainly of compacted clay minerals, quartz, and minor iron oxides

AI-generated identification · may be incorrect

Thin, layered, dull earthy-brown fragment with very fine grain and uneven/fissile breakage; estimated Mohs hardness 2–3, nonmetallic luster, negligible visible crystals, and low specific gravity around 2.2–2.7. Exact identification is limited by the photograph.

Identified September 7, 2026More sedimentary →

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At a glance

Common name: Brown shale or mudstone fragment
Scientific name: Likely fissile claystone/shale, composed mainly of compacted clay minerals, quartz, and minor iron oxides
Category: sedimentary
Identified: September 7, 2026
Method: Standard

AI Estimated Value

Approximately $0–$5 for an ordinary fragment; higher prices require unusual fossils, color, locality, or documented provenance.

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 clay- and silt-sized sediment accumulated in quiet water, was compacted, and cemented during burial; age could range from very young sediment to hundreds of millions of years depending on source locality.

Uses & applications

Common shale is used for brick, cement, roofing products, and aggregate, while attractive slabs may be collected; this small fragment has essentially no commercial value.

Geological facts

Its thin layering and earthy color are typical of fine-grained sedimentary rock, though weathered slate or a clay-rich mudstone can look similar.

Field identification & locations

Look for persistent bedding, a dull surface, very fine texture, and splitting along layers; it may scratch easily with a knife and usually does not fizz with dilute hydrochloric acid. Common worldwide in former lake, floodplain, and marine basins.