fossil

Likely weathered fossil shell or fossiliferous limestone

Indeterminate molluscan fossil, possibly a bivalve or brachiopod preserved in carbonate rock

AI-generated identification · may be incorrect

Gray-brown, irregularly ridged specimen with dull to slightly waxy luster; apparent shell folds and growth ribs. Hardness is approximately 3–4 if calcitic, with weak cleavage in the enclosing carbonate and specific gravity near 2.6–2.8.

Identified August 13, 2026More fossil →

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At a glance

Common name: Likely weathered fossil shell or fossiliferous limestone
Scientific name: Indeterminate molluscan fossil, possibly a bivalve or brachiopod preserved in carbonate rock
Category: fossil
Identified: August 13, 2026
Method: Standard

AI Estimated Value

Approximately $5–$30 for a common unidentified specimen; $30–$150 or more if preparation, locality, preservation, or taxonomic identification 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

Likely formed when a marine shell was buried and mineralized or retained as calcite in sediment, commonly during Paleozoic–Mesozoic marine deposition; the exact age cannot be determined from the image.

Uses & applications

Primarily a collecting, educational, or decorative specimen; carbonate fossils may be cut or displayed, but this example is not suitable for jewelry identification without preparation.

Geological facts

The raised ribbing and bilateral shell-like form are more consistent with a fossil than an ordinary igneous or metamorphic rock, though the image is insufficient for genus-level identification.

Field identification & locations

Look for repeated growth ribs, symmetry, shell margins, and carbonate matrix; a drop of dilute hydrochloric acid would fizz on calcite, but test only an inconspicuous spot. Common sources include marine limestone deposits worldwide.