fossil

Fossil bivalve shell in matrix

Likely fossilized oyster or mussel (Bivalvia), with a nacreous aragonite shell; exact genus and age require locality and preparation details

AI-generated identification · may be incorrect

Dark gray-brown sedimentary matrix surrounds a glossy, strongly ribbed shell showing iridescent blue-gray nacre. Original shell aragonite may be partly recrystallized; hardness is typically about 3–4 Mohs, with curved growth bands and pronounced radial ribs.

Identified September 13, 2026More fossil →

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At a glance

Common name: Fossil bivalve shell in matrix
Scientific name: Likely fossilized oyster or mussel (Bivalvia), with a nacreous aragonite shell; exact genus and age require locality and preparation details
Category: fossil
Identified: September 13, 2026
Method: Standard

AI Estimated Value

Approximately $15–$100 for a common matrix specimen; $100–$500+ if unusually complete, iridescent, well-prepared, and scientifically identified.

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 bivalve was buried in sediment and preserved as a fossil, commonly through mineral replacement or infilling during diagenesis. The geological age cannot be determined reliably from the image alone; comparable specimens range from Paleozoic to Cenozoic deposits.

Uses & applications

Primarily a teaching, display, and collecting specimen; fossil shell material can occasionally be polished for ornament, but this matrix piece is not generally used industrially or as jewelry.

Geological facts

The silvery sheen likely reflects preserved nacre, an uncommon and attractive form of shell preservation. Identifying the species requires examining hinge teeth, shell symmetry, rib pattern, and stratigraphic locality.

Field identification & locations

Look for two-valved symmetry, a hinge area, growth lines, and radial ribs embedded in limestone or mudstone. Common fossil bivalves occur in marine sedimentary rocks worldwide, especially coastal Cretaceous and Cenozoic formations.