fossil

Fossil brachiopod or bivalve shell

Likely a ribbed brachiopod, possibly Spiriferida or Productida; exact identification requires locality and shell details

AI-generated identification · may be incorrect

Fossilized calcitic shell with strong radial ribs, yellow-brown weathering, and dull to waxy luster; calcite hardness about 3, commonly showing cleavage and relatively high density (SG ~2.7).

Identified August 19, 2026More fossil →

Explore Fossil brachiopod or bivalve shell in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Fossil brachiopod or bivalve shell
Scientific name: Likely a ribbed brachiopod, possibly Spiriferida or Productida; exact identification requires locality and shell details
Category: fossil
Identified: August 19, 2026
Method: Standard

AI Estimated Value

About $10–$75 for a common incomplete specimen; $100–$300+ if exceptionally complete, large, 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

Fossilized calcitic shell with strong radial ribs, yellow-brown weathering, and dull to waxy luster; calcite hardness about 3, commonly showing cleavage and relatively high density (SG ~2.7).

Formation & geological history

A marine shell buried in carbonate sediment and mineralized during diagenesis, likely Paleozoic in age (about 541–252 million years ago). The bilateral ribbing and thick, curved form are consistent with a brachiopod, though a bivalve is possible.

Uses & applications

Primarily a teaching, display, and collecting specimen; fossil shells can also be used in educational geology and paleontology exhibits.

Geological facts

Brachiopods resemble clams but have symmetry through each valve rather than between the two valves. Radial ribs strengthened the shell and may have helped stabilize it on the seafloor.

Field identification & locations

Look for repeated ribs, a distinct hinge or beak, shell symmetry, and mineral-filled internal surfaces; acid testing is not recommended unless damage is acceptable. Common in Paleozoic limestone deposits worldwide, especially North America and Europe.