fossil

Fossil-bearing limestone collection

Bioclastic limestone, commonly containing fossilized corals, bivalves, gastropods, and other marine invertebrates; composition primarily calcite (CaCO₃)

AI-generated identification · may be incorrect

Typically gray, cream, tan, or reddish-brown with a dull to slightly crystalline luster; Mohs hardness about 3, rhombohedral calcite cleavage, and specific gravity near 2.7. Visible shell molds, chambers, ribs, and porous coral textures strongly indicate fossiliferous carbonate rock.

Identified August 22, 2026More fossil →

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At a glance

Common name: Fossil-bearing limestone collection
Scientific name: Bioclastic limestone, commonly containing fossilized corals, bivalves, gastropods, and other marine invertebrates; composition primarily calcite (CaCO₃)
Category: fossil
Identified: August 22, 2026
Method: Standard

AI Estimated Value

About $5–$30 per common specimen; $30–$200+ for large, well-preserved, identifiable fossils or attractive polished pieces.

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 and skeletal material accumulated on ancient seafloors, were compacted, and cemented by calcite-rich groundwater. Individual pieces may range from Paleozoic to Cenozoic age, depending on locality.

Uses & applications

Used for educational collections, lapidary work, decorative stone, and occasionally building limestone; fossils are primarily valued by collectors and museums.

Geological facts

Acid testing produces vigorous fizzing because calcite dissolves in dilute hydrochloric acid or vinegar, though vinegar reacts more slowly. Some porous pieces may be coral colonies or weathered shell beds rather than solid limestone.

Field identification & locations

Common in former shallow-marine regions worldwide, including Florida, the Caribbean, Europe, and many U.S. limestone belts. Identify by fossil shapes and acid reaction; avoid destructive cleaning or polishing if scientific details are important.