fossil

Fossil brachiopod shell

Brachiopoda; likely a ribbed strophomenid or productid brachiopod

AI-generated identification · may be incorrect

Calcareous shell fossil, tan-brown with strong radial ribs and bilateral symmetry; calcite composition, hardness about 3 Mohs, vitreous to dull luster, and commonly two unequal valves. Specific gravity is approximately 2.7–2.9.

Identified September 7, 2026More fossil →

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Physical properties

Formation & geological history

A marine filter-feeding animal secreted the shell, which was buried and mineralized in sediment; most similar specimens are Paleozoic, roughly 541–252 million years old, though brachiopods still live today.

Uses & applications

Primarily a fossil-collecting and educational specimen; not generally used in construction or jewelry, though polished fossil material may be decorative.

Geological facts

Brachiopods resemble clams but differ in symmetry: each valve is usually symmetrical across its own centerline, unlike bivalves. Radial ribs strengthened the shell and may have helped stabilize it on the seafloor.

Field identification & locations

Identify it by the fan-shaped, strongly ribbed shell and symmetry around the midline; common fossil localities include Paleozoic marine limestones worldwide, especially North America, Europe, and China. Exact identification requires the opposite valve and locality data.