fossil

Marine gastropod shell

Calcareous mollusk shell, primarily aragonite (CaCO₃), likely a whelk or conch

AI-generated identification · may be incorrect

Hardness about 3–4 Mohs; cream-white with brown markings, pearly to dull luster, spiral coiled structure, and prominent growth ridges. It is biogenic carbonate rather than a rock-forming mineral crystal.

Identified September 12, 2026More fossil →

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Physical properties

Formation & geological history

Secreted by a marine gastropod; the shell may be modern or subfossil, and burial can eventually preserve it as fossil limestone. The photograph alone cannot establish its species or geological age.

Uses & applications

Used decoratively, in shell collections, crafts, and occasionally as aquarium or garden material; powdered shells can amend soil, though this specimen is better preserved intact.

Geological facts

Shells commonly consist of aragonite, a polymorph of calcite, and may recrystallize to calcite during fossilization. The spiral geometry reflects biological growth rather than inorganic crystal growth.

Field identification & locations

Identify it by its asymmetric spiral coil, aperture, whorls, and growth lines; common on marine beaches and in coastal sediments worldwide. A complete, naturally colored shell is more collectible than a worn or bleached example.