Rock Identifier
Fossil gastropod shell (Spiral marine gastropod fossil; likely a small ammonite-like or gastropod shell, exact taxon indeterminate) — fossil
fossil

Fossil gastropod shell

Spiral marine gastropod fossil; likely a small ammonite-like or gastropod shell, exact taxon indeterminate

AI-generated identification · may be incorrect

White to pale gray, tightly coiled spiral with visible whorls and a small central aperture; composed mainly of recrystallized calcium carbonate (aragonite or calcite). Mohs hardness about 3–4, generally dull to pearly luster, and curved shell-layer structure rather than mineral cleavage.

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Physical properties

White to pale gray, tightly coiled spiral with visible whorls and a small central aperture; composed mainly of recrystallized calcium carbonate (aragonite or calcite). Mohs hardness about 3–4, generally dull to pearly luster, and curved shell-layer structure rather than mineral cleavage.

Formation & geological history

Formed as a marine snail shell, later buried in sediment and mineralized or preserved during diagenesis; age cannot be determined from the image and may range from Paleozoic to Recent fossil-bearing deposits.

Uses & applications

Primarily a natural-history collectible, educational specimen, or craft decoration; not normally used industrially or as jewelry unless polished or set.

Geological facts

The spiral geometry reflects gastropod growth, with each whorl added around the shell’s aperture. Similar small fossils commonly occur in limestone, beach deposits, and unconsolidated marine sediments.

Field identification & locations

Identify by its regular logarithmic coil, whorls, and shell texture; distinguish it from a mineral by its biological growth pattern. Common in coastal sedimentary rocks and fossil beaches worldwide.

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Phylum Echinodermata, Class Crinoidea

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

Bioclastic limestone, composed chiefly of calcite (CaCO₃)

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Porous limestone pebble

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

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Weathered fossil bone fragment (identification uncertain)

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

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