fossil

Polished fossiliferous limestone (likely crinoidal or shell-rich limestone)

Bioclastic limestone, primarily calcite (CaCO₃), containing fossil fragments

AI-generated identification · may be incorrect

Dark brown to black, glossy polished surface with abundant pale, elongated fossil fragments; calcite hardness ~3 Mohs, vitreous to waxy luster, irregular fracture, and no consistent cleavage visible. It should effervesce strongly with dilute hydrochloric acid or vinegar if calcitic.

Identified August 30, 2026More fossil →

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At a glance

Common name: Polished fossiliferous limestone (likely crinoidal or shell-rich limestone)
Scientific name: Bioclastic limestone, primarily calcite (CaCO₃), containing fossil fragments
Category: fossil
Identified: August 30, 2026
Method: Standard

AI Estimated Value

About $10–$40 for a small polished common specimen; $50–$150 or more for unusually attractive, well-identified fossil-rich material.

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 when marine skeletal debris accumulates, is buried, compacted, and cemented by calcite, commonly during Paleozoic–Mesozoic marine deposition. The specimen has been cut and polished, obscuring much of its natural texture.

Uses & applications

Used as a decorative stone, paperweight, educational fossil specimen, or lapidary material; similar limestone is used for aggregate, cement, and architectural stone.

Geological facts

The pale markings may be crinoid-columnals, shell fragments, or other marine fossils; exact identification requires a close examination of the patterns and acid response.

Field identification & locations

Common in fossil-rich marine limestone from regions such as the central United States, Europe, and North Africa. Look for repeated biological structures rather than random veining; avoid prolonged acid testing on polished surfaces.