fossil

Fossiliferous shale or mudstone with a trilobite-like fossil

Likely a trilobite impression/remnant in dark shale; exact taxon and host rock require locality and preparation details

AI-generated identification · may be incorrect

Dark gray to brown, fine-grained, dull to slightly silky surface with layered cleavage; apparent fossil shows segmented, curved morphology. Host shale typically has Mohs hardness 2–3, while trilobite material is commonly calcite or altered mineral matter.

Identified August 28, 2026More fossil →

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At a glance

Common name: Fossiliferous shale or mudstone with a trilobite-like fossil
Scientific name: Likely a trilobite impression/remnant in dark shale; exact taxon and host rock require locality and preparation details
Category: fossil
Identified: August 28, 2026
Method: Standard

AI Estimated Value

About $10–$100 for a common partial specimen; $100–$1,000+ if the fossil is genuine, well-prepared, identifiable, and nearly complete.

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 Cambrian–Permian marine mud buried and lithified, preserving a trilobite exoskeleton or impression; the specimen’s precise geological age cannot be determined from the image alone.

Uses & applications

Primarily a teaching and collecting specimen; shale may be used locally as fill or low-grade building material, but fossil-bearing pieces are generally not commercial construction stone.

Geological facts

Trilobites were extinct marine arthropods with segmented bodies and compound eyes; many fossils preserve only flattened impressions rather than three-dimensional shells.

Field identification & locations

Look for bilateral symmetry, repeated body segments, a distinct cephalon and tail shield, and fine bedding in the matrix. Common trilobite-bearing rocks occur in Morocco, Utah, New York, China, and Scandinavia.