fossil

Fossilized bivalve shell or shell-rich limestone

Likely an indeterminate fossil mollusk; calcite/aragonite (CaCO₃), possibly preserved in limestone

AI-generated identification · may be incorrect

Gray-green to tan, elongated and strongly ribbed, with an irregular weathered surface and probable shell growth lines. Original shell mineral may be calcite or altered to calcite; hardness about 3, nonmetallic luster, low cleavage, and specific gravity roughly 2.6–2.8.

Identified August 30, 2026More fossil →

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At a glance

Common name: Fossilized bivalve shell or shell-rich limestone
Scientific name: Likely an indeterminate fossil mollusk; calcite/aragonite (CaCO₃), possibly preserved in limestone
Category: fossil
Identified: August 30, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common weathered specimen; $50–$200+ if exceptionally complete, well-prepared, or from a documented locality.

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

Most likely a marine mollusk shell mineralized by burial and diagenesis, potentially tens to hundreds of millions of years old; exact age requires locality and preparation details. The surrounding material may be carbonate rock.

Uses & applications

Primarily a collecting, educational, or decorative specimen; carbonate fossil material can also be used as aggregate or limestone feedstock when abundant, though this individual is not industrially significant.

Geological facts

The repeated ridges and tapered outline suggest a shell rather than an igneous or metamorphic rock. Surface holes may represent weathering, dissolution, or bioerosion.

Field identification & locations

Look for bilateral shell symmetry, continuous growth ribs, and a calcitic reaction to dilute hydrochloric acid or vinegar; avoid testing valuable specimens. Common in marine sedimentary formations worldwide, especially limestone and shale exposures.