fossil

Polished fossiliferous limestone

Bioclastic limestone, likely containing a solitary rugose coral or shell fossil (identification uncertain from image)

AI-generated identification · may be incorrect

Gray-brown, fine-grained carbonate matrix with a circular fossil cross-section and concentric growth features; dull to lightly polished luster, Mohs hardness 3–4, typically non-cleavable, specific gravity about 2.3–2.7. It should effervesce strongly with dilute hydrochloric acid.

Identified August 28, 2026More fossil →

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At a glance

Common name: Polished fossiliferous limestone
Scientific name: Bioclastic limestone, likely containing a solitary rugose coral or shell fossil (identification uncertain from image)
Category: fossil
Identified: August 28, 2026
Method: Standard

AI Estimated Value

Approximately $10–$40 for a small polished specimen; $50–$150 if the fossil is unusually large, well-preserved, or clearly identified.

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 and cemented marine skeletal debris, probably Paleozoic to Mesozoic in age; later cut and polished as a display specimen. The central fossil may represent coral, a crinoid-related structure, or a shell section.

Uses & applications

Used as a teaching, lapidary, and decorative specimen; similar fossil limestone is also used for aggregate, cement, and dimension stone. Value is mainly aesthetic and educational.

Geological facts

The concentric rings record biological growth or internal skeletal structure rather than mineral crystal zoning. Polishing can reveal fossils that are difficult to recognize on a weathered surface.

Field identification & locations

Look for carbonate fizz, a relatively soft surface, and visible fossil textures; avoid confusing it with chert or concrete. Common sources include marine Paleozoic limestone regions worldwide, especially North America and Europe.