fossil

Fossil Brachiopod

Phylum Brachiopoda

Hardness 3 to 4, typically gray, brown, or tan in color with a dull to earthy luster, exhibiting symmetrical ribbed shell structures.

Identified October 26, 2026More fossil →

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Physical properties

Hardness 3 to 4, typically gray, brown, or tan in color with a dull to earthy luster, exhibiting symmetrical ribbed shell structures.

Formed through the fossilization of marine invertebrate animals in shallow Paleozoic and Mesozoic seas, typically over hundreds of millions of years.

Valued by fossil collectors, used in educational displays, and serves as an important index fossil for dating sedimentary rock layers.

Brachiopods date back over 500 million years to the Cambrian period and superficially resemble clams, though they are phylogenetically distinct.

Identify in sedimentary limestone or shale by their characteristic symmetrical bivalve shells with a distinct hinge line. Common worldwide.

Probable fossil-bearing rock or mineral concretion

Unidentified carbonate-rich concretion with a possible fossil inclusion

Likely fossil oyster shell

Fossilized bivalve shell; exact species cannot be identified from the image

Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

Fossiliferous limestone (likely a crinoidal or shell-fragment limestone)

Bioclastic limestone, composed chiefly of calcite (CaCO₃)

Porous limestone pebble

Calcite-rich limestone (primarily CaCO₃); exact identification is uncertain from the image

Weathered fossil bone fragment (identification uncertain)

Fossilized bone; exact taxon and mineral composition cannot be determined from the image