fossil

Fossil shell fragment, likely bivalve or gastropod

Fossilized calcium-carbonate shell; likely aragonite/calcite replaced by calcite

AI-generated identification · may be incorrect

Tan, irregular curved fragment with a hollow internal cavity and rough, granular surface; original shell structure appears partly preserved. Mohs hardness about 3–4, earthy to dull luster, no obvious crystal cleavage.

Identified September 22, 2026More fossil →

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At a glance

Common name: Fossil shell fragment, likely bivalve or gastropod
Scientific name: Fossilized calcium-carbonate shell; likely aragonite/calcite replaced by calcite
Category: fossil
Identified: September 22, 2026
Method: Standard

AI Estimated Value

Typically $1–$15 as an unidentified fragment; professionally identified or exceptionally preserved fossils may be worth $20–$100+.

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 biological shell accumulated in marine or freshwater sediment and was buried, compacted, and mineralized during diagenesis; its exact geological age cannot be determined from the photograph. The cavity may be an internal mold or broken chamber.

Uses & applications

Primarily a teaching, collecting, and decorative specimen; not useful as a gemstone or construction material.

Geological facts

The hollow form and curved wall suggest shell architecture rather than an igneous or metamorphic rock. Acid testing with dilute hydrochloric acid or vinegar may produce effervescence if carbonate remains exposed.

Field identification & locations

Look for repeated growth lines, symmetry, hinge features, or spiral curvature to identify the organism; common in limestone, shale, and coastal sediment deposits worldwide. Avoid aggressive cleaning or acid if preservation matters.