sedimentary

Fossiliferous limestone (likely crinoidal or shell-bearing limestone)

Calcite-rich carbonate rock; predominantly CaCO₃ (calcite), with possible bioclasts and minor dolomite/clay

AI-generated identification · may be incorrect

Typically Mohs 3, pale gray-beige, earthy to dull/vitreous on fresh surfaces, with irregular fracture and weak-to-no cleavage as a rock. The granular, whitish fossil fragments and acid-reactive calcite are characteristic.

Identified August 25, 2026More sedimentary →

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At a glance

Common name: Fossiliferous limestone (likely crinoidal or shell-bearing limestone)
Scientific name: Calcite-rich carbonate rock; predominantly CaCO₃ (calcite), with possible bioclasts and minor dolomite/clay
Category: sedimentary
Identified: August 25, 2026
Method: Standard

AI Estimated Value

$2–$15 as a common hand specimen; $20–$100+ if fossils are exceptionally clear, attractive, or professionally prepared.

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 marine shells, crinoid debris, or other carbonate sediments accumulated, compacted, and cemented on an ancient seafloor; age cannot be determined from the image and may range from Paleozoic to Cenozoic.

Uses & applications

Used as aggregate, cement and lime feedstock, dimension stone, and a collector fossil specimen; attractive polished pieces may be used decoratively rather than as jewelry.

Geological facts

A drop of dilute hydrochloric acid or vinegar may fizz on exposed surfaces, confirming calcite-rich carbonate. Fossil fragments can be easier to see after wetting or cutting.

Field identification & locations

Common in former shallow-marine sedimentary basins worldwide, including the Midwest and Appalachians of North America, Europe, and Asia. Look for visible shell/crinoid structures, soft scratching by steel, and strong acid effervescence.