fossil

Fossil brachiopod

Brachiopoda; likely a spiriferid or strophomenid brachiopod

AI-generated identification · may be incorrect

A dark brown, mineral-replaced shell fossil with strong radial ribs and a preserved curved shell form; original calcite shell is commonly recrystallized. Mohs hardness is approximately 3–4, with dull to weakly pearly luster and bilateral shell symmetry.

Identified September 10, 2026More fossil →

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Physical properties

Formation & geological history

Brachiopods were marine filter-feeders that lived on Paleozoic seafloors, especially during the Devonian–Permian (about 419–252 million years ago). Burial and diagenesis mineralized or preserved the calcium-carbonate shell in sedimentary rock.

Uses & applications

Primarily a collector, teaching, and decorative specimen; it has no significant industrial or jewelry use.

Geological facts

Brachiopods resemble bivalve mollusks but have unequal valves and bilateral symmetry through each valve. Radial ribs and a beak-like pedicle valve are useful taxonomic features.

Field identification & locations

Identify it by the paired ribbed valves, symmetry, and fossilized shell texture; common deposits occur in Paleozoic marine limestones and shales worldwide, including North America, Europe, and Australia.