fossil

Fossil brachiopod or bivalve shell

Indeterminate fossilized shell; likely a ribbed brachiopod (Order Productida or Spiriferida)

AI-generated identification · may be incorrect

A rounded, ribbed shell impression with gray-beige coloration and a dull, stone-like luster; original calcite shell is likely replaced or heavily mineralized. Calcite hardness is about Mohs 3, with curved/radial ribs and possible bilateral symmetry.

Identified August 18, 2026More fossil →

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Physical properties

Formation & geological history

Formed when a marine shell was buried and mineralized in carbonate sediment, commonly during the Paleozoic Era (about 541–252 million years ago). Weathering later exposed and rounded the specimen.

Uses & applications

Primarily a collectible and educational fossil; fossiliferous limestone may also be used as aggregate or building stone, but this individual has no practical industrial use.

Geological facts

The strong radial ribs are typical of Paleozoic brachiopods, though a detailed view of both valves and the hinge is needed for certain identification.

Field identification & locations

Look for consistent ribbing, shell symmetry, a hinge or valve seam, and calcite-rich texture; common in limestone beds and gravel derived from marine sedimentary rocks. Estimated value: $5–$30 for a common, small specimen; $50+ if exceptionally complete or identifiable.