sedimentary
Fossilized Brachiopod
Brachiopoda (e.g., Rhynchonellida or Spiriferida)
Dull luster, tan to light brown color, hardness of 3-4 (calcite-based), distinct ribbed or sulcate texture, bilateral symmetry across the valves.
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Physical properties
Dull luster, tan to light brown color, hardness of 3-4 (calcite-based), distinct ribbed or sulcate texture, bilateral symmetry across the valves.
Formation & geological history
Formed during the Paleozoic or Mesozoic eras (approx. 500 to 65 million years ago) through the permineralization or recrystallization of marine shells in low-energy marine shelf environments.
Uses & applications
Used primarily for paleontology education, stratigraphy for dating rock layers, and as a popular collectible item for hobbyists.
Geological facts
Brachiopods are often mistaken for clams, but they are genetically distinct and belong to their own phylum. They were among the most abundant marine life forms during the Devonian period.
Field identification & locations
Look for symmetrical ribbed patterns in limestone or shale outcrops. Common in areas with exposed ancient sea beds such as the Midwestern USA, UK, and Morocco.
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