fossil

Fossilized bivalve or ammonite fragment

Calcareous fossil; likely a mollusk shell preserved as calcite (taxonomic identification uncertain)

AI-generated identification · may be incorrect

Cream to gray, finely textured, low-gloss surface with apparent shell growth lines and curved ribbing; mainly calcite, Mohs hardness about 3, with poor cleavage and specific gravity near 2.7. The rounded form and layered ridges resemble a weathered fossil shell rather than a crystalline mineral.

Identified August 18, 2026More fossil →

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At a glance

Common name: Fossilized bivalve or ammonite fragment
Scientific name: Calcareous fossil; likely a mollusk shell preserved as calcite (taxonomic identification uncertain)
Category: fossil
Identified: August 18, 2026
Method: Standard

AI Estimated Value

About $5-$30 for a common weathered specimen; $50-$200+ if exceptionally complete, identifiable, 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

A marine mollusk shell was originally aragonite or calcite and became mineralized or replaced by calcite during burial in limestone-rich sediment. Its exact geological age cannot be determined from the photograph, but such fossils range from Paleozoic to Cenozoic deposits.

Uses & applications

Primarily collected, displayed, and used for educational study; fossil-bearing limestone may also be used as aggregate or ornamental stone.

Geological facts

The visible ridges may represent shell growth lines, ribs, or preservation fractures. Acid will typically produce effervescence on exposed calcite, though testing can damage the specimen.

Field identification & locations

Look for bilateral shell symmetry, repeated growth bands, and a continuous curved shell margin; compare with local fossil guides. Common in marine limestones worldwide, especially coastal sedimentary formations.