sedimentary

Polished fossiliferous limestone (probable crinoidal limestone)

Calcite-rich limestone; chiefly CaCO₃, with possible crinoid fossil fragments

AI-generated identification · may be incorrect

Hardness about 3 Mohs; tan-brown, gray-edged, and weakly polished with dull to waxy luster. Likely fine-grained calcite containing curved or granular fossil textures; it should effervesce strongly with dilute hydrochloric acid or vinegar.

Identified September 5, 2026More sedimentary →

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At a glance

Common name: Polished fossiliferous limestone (probable crinoidal limestone)
Scientific name: Calcite-rich limestone; chiefly CaCO₃, with possible crinoid fossil fragments
Category: sedimentary
Identified: September 5, 2026
Method: Standard

AI Estimated Value

About $5-$25 for a common polished specimen; $30-$100 or more if fossils are clearly identifiable, attractive, and provenance is documented.

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 marine carbonate mud and skeletal debris that lithified into limestone, commonly during the Paleozoic or Mesozoic; the exact age cannot be determined from the image. Polishing appears human-applied.

Uses & applications

Used as decorative stone, lapidary material, architectural limestone, and a collector fossil specimen; limestone is also important in cement and aggregate production.

Geological facts

The dark curved markings may be fossil fragments, stylolites, or mineral veins rather than true crystals. Crinoidal limestone commonly shows repeated disk- or crescent-like pieces in a calcite matrix.

Field identification & locations

Look for visible fossil shapes, a relatively soft surface, and acid fizz; a steel knife may scratch it. Common sources include marine limestone regions worldwide, especially North America and Europe.