fossil

Fossil brachiopod shell

Likely a spiriferid brachiopod; exact genus and age require locality and preparation

AI-generated identification · may be incorrect

A bilateral, ribbed, calcareous shell fossil with yellow-brown weathering patina and possible iron-oxide staining. Calcite shell material is Mohs hardness about 3, has pearly to dull luster, and commonly preserves strong radial ribs and a pronounced fold-and-sulcus form.

Identified August 19, 2026More fossil →

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Physical properties

Formation & geological history

Brachiopods were marine filter feeders whose shells accumulated in Paleozoic seafloors, especially during the Devonian–Permian (about 419–252 million years ago), then lithified and weathered free from sediment.

Uses & applications

Primarily a teaching, collecting, and decorative specimen; it has no significant industrial use. Value depends on species, preservation, completeness, preparation, and locality.

Geological facts

Brachiopods resemble clams but have unequal valves and bilateral symmetry through each valve, unlike bivalves, whose symmetry is between valves. The elongated outline and dense ribs are typical of many spiriferid forms.

Field identification & locations

Look for a central fold and sulcus, radial ribbing, a hinge or beak, and calcite reaction to dilute hydrochloric acid. Common in Paleozoic marine limestones and shales worldwide, particularly North America and Europe.