fossil

Fossiliferous limestone, likely coral or shell-rich fragment

Calcite (CaCO₃), commonly bioclastic limestone containing fossilized marine organisms

AI-generated identification · may be incorrect

Gray, fine- to medium-grained carbonate rock with prominent ribbed/laminated fossil textures and dull to weakly pearly luster. Calcite has Mohs hardness 3, rhombohedral cleavage, and reacts vigorously with dilute hydrochloric acid; the specimen’s dense fossil framework may obscure individual crystals.

Identified August 17, 2026More fossil →

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At a glance

Common name: Fossiliferous limestone, likely coral or shell-rich fragment
Scientific name: Calcite (CaCO₃), commonly bioclastic limestone containing fossilized marine organisms
Category: fossil
Identified: August 17, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common fragment; $30–$150+ if the fossil identity, preservation, locality, or display quality is exceptional.

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, corals, or other carbonate skeletons accumulated, were compacted, and cemented on an ancient seafloor; the exact geologic age cannot be determined from the image. Such deposits range from Paleozoic to Cenozoic in age.

Uses & applications

Used as aggregate, cement and lime feedstock, building stone, and ornamental material; identifiable fossil pieces are mainly valued by collectors and educators.

Geological facts

The repeating ridges may represent a colonial coral, brachiopod, or shell impression rather than mineral banding. Acid testing and a close examination of the fossil symmetry would help distinguish these possibilities.

Field identification & locations

Common in marine sedimentary formations worldwide, especially limestone belts. Look for carbonate reaction, low hardness, fossil symmetry, and a lack of glassy igneous texture; avoid acid testing on valuable specimens.