sedimentary

Tumbled fossiliferous limestone (likely fossiliferous marble)

Fossiliferous limestone, composed mainly of calcite (CaCO₃); the pale circular fossils appear to be shell or crinoid fragments

AI-generated identification · may be incorrect

Dark gray to black matrix with cream-colored fossil outlines and fragments; calcite has Mohs hardness 3 and a vitreous to dull luster. The polished surface obscures texture; calcite is trigonal and commonly effervesces in dilute acid.

Identified September 25, 2026More sedimentary →

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At a glance

Common name: Tumbled fossiliferous limestone (likely fossiliferous marble)
Scientific name: Fossiliferous limestone, composed mainly of calcite (CaCO₃); the pale circular fossils appear to be shell or crinoid fragments
Category: sedimentary
Identified: September 25, 2026
Method: Standard

AI Estimated Value

About $2–$15 for a small tumbled specimen, depending on polish, size, and fossil detail.

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 as carbonate mud and marine shell remains accumulated and lithified on an ancient seafloor; later burial and recrystallization may have produced marble. The rock’s age cannot be determined from the image.

Uses & applications

Commonly polished into decorative stones, jewelry, and ornaments; limestone is also used for cement and building stone.

Geological facts

Fossils are preserved as contrasting carbonate material within the darker matrix, making each piece’s pattern distinctive.

Field identification & locations

Look for recognizable fossil outlines in a calcite-rich rock; limestone commonly occurs in former marine sedimentary basins worldwide. A close examination or acid test can help confirm calcite.