fossil

Clam Fossil

Bivalvia fossil

Hardness 3.5 to 4 on the Mohs scale, white to gray color, dull to pearly luster, trigonal or asymmetrical shell structure.

Identified October 27, 2026More fossil →

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Physical properties

Hardness 3.5 to 4 on the Mohs scale, white to gray color, dull to pearly luster, trigonal or asymmetrical shell structure.

Formed through permineralization where organic shell material is replaced by minerals like calcite or silica over millions of years.

Used in educational displays, fossil collecting, and decorative display pieces.

Bivalve fossils date back over 500 million years to the Cambrian period and are vital index fossils for dating sedimentary strata.

Found worldwide in sedimentary rock formations, especially ancient marine shales and limestones.

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