sedimentary

Fossilized Brachiopod

Phylum Brachiopoda (Calcium Carbonate/Silica replacement)

AI-generated identification · may be incorrect

Hardness: 3-3.5 (if calcite) or 7 (if silicified); Color: Tan, grey, or white; Luster: Dull to earthy; Structure: Bilateral symmetry with distinct growth lines and ribbing (costae).

Hardness: 3-3
Color: Tan, grey, or white
Luster: Dull to earthy

Identified June 21, 2026More sedimentary →

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Physical properties

Hardness: 3-3.5 (if calcite) or 7 (if silicified); Color: Tan, grey, or white; Luster: Dull to earthy; Structure: Bilateral symmetry with distinct growth lines and ribbing (costae).

Formation & geological history

Formed in ancient marine environments when the shells of lamp shells were buried in sediment and lithified over millions of years, commonly from the Paleozoic Era.

Uses & applications

Paleontological study, educational tools, and common items for fossil collectors.

Geological facts

Brachiopods are not mollusks, despite their appearance; they have a unique feeding organ called a lophophore. They have survived for over 500 million years.

Field identification & locations

Look for a clam-like shell with one valve larger than the other and distinctive radial ribbing. Commonly found in limestone outcrops and riverbeds in the Midwest and Appalachia.