fossil

Brachiopod Fossil in Sedimentary Rock

Phylum Brachiopoda fossil imprint in sedimentary matrix

AI-generated identification · may be incorrect

Hardness varies by host rock (typically Mohs 3-4 for limestone or shale), brown to dark grey color, dull luster, amorphous overall nodule with radial-ribbed impression of a brachiopod shell.

Identified August 3, 2026More fossil →

Explore Brachiopod Fossil in Sedimentary Rock in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness varies by host rock (typically Mohs 3-4 for limestone or shale), brown to dark grey color, dull luster, amorphous overall nodule with radial-ribbed impression of a brachiopod shell.

Formation & geological history

Formed through permineralization or as a mold/cast fossil in ancient marine sedimentary environments, typically dating from the Paleozoic era (e.g., Ordovician to Carboniferous periods, 300-500 million years ago).

Uses & applications

Educational specimen, paleontological study, and collector display item.

Geological facts

Brachiopods are marine animals that superficially resemble clams, though they are phylogenetically distinct. They are one of the most common fossils found in Paleozoic marine rocks.

Field identification & locations

Look for symmetrical, ribbed shell impressions or molds within rounded river rocks or sedimentary outcrops. Common in regions with ancient shallow seas, such as the Midwestern United States and parts of Western Europe.