fossil

Brachiopod Fossil

Phylum Brachiopoda

Hardness: 3-4 (Calcite replacement); Color: Tan, grey, or brownish-white; Luster: Dull to earthy; Shell-like structure with two valves; Symmetrical along the midline.

Hardness: 3-4 (Calcite replacement)
Color: Tan, grey, or brownish-white
Luster: Dull to earthy

Identified July 13, 2026More fossil →

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Physical properties

Hardness: 3-4 (Calcite replacement); Color: Tan, grey, or brownish-white; Luster: Dull to earthy; Shell-like structure with two valves; Symmetrical along the midline.

Formation & geological history

Formed through the fossilization of marine invertebrates that lived on the ocean floor. Most abundant during the Paleozoic era (541 to 252 million years ago), typically found in limestone or shale formed in shallow seas.

Uses & applications

Primarily for educational purposes, scientific research, and hobbyist collecting. Used as index fossils for dating rock layers.

Geological facts

Although they look like clams, brachiopods are not closely related to mollusks; their symmetry is different (across the shell rather than between shells). They have survived for over 500 million years.

Field identification & locations

Identify in the field by searching sedimentary outcrops, especially limestone. Look for the distinct 'lamp shell' shape and ribbing. Common in the Midwest USA and UK.