fossil

Mother of Pearl

Nacre (Aragonite and Conchiolin)

Hardness of 3.5 to 4 on the Mohs scale, iridescent white color, pearly luster, and an organic-mineral composite crystal structure.

Identified November 6, 2026More fossil →

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Physical properties

Hardness of 3.5 to 4 on the Mohs scale, iridescent white color, pearly luster, and an organic-mineral composite crystal structure.

Formed as an inner shell layer by mollusks over extended biological periods in marine environments.

Widely used in jewelry, decorative inlay, buttons, and high-end crafts.

Nacre exhibits a brick-like arrangement of microscopic platelets that make it exceptionally tough and fracture-resistant.

Identified by its distinctive iridescent play of light, commonly sourced from pearl oysters and abalone.

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