Rock Identifier
Small shell fragment (likely gastropod or bivalve fossil) (Fossilized calcium-carbonate shell; chiefly aragonite or calcite (CaCO₃)) — fossil
fossil

Small shell fragment (likely gastropod or bivalve fossil)

Fossilized calcium-carbonate shell; chiefly aragonite or calcite (CaCO₃)

AI-generated identification · may be incorrect

Tiny cream-white, translucent fragment with ribbed growth lines and a pearly luster; hardness about 3–4 Mohs, brittle, with no visible crystal faces. The spiral/ridged form suggests shell rather than a crystalline mineral.

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Physical properties

Tiny cream-white, translucent fragment with ribbed growth lines and a pearly luster; hardness about 3–4 Mohs, brittle, with no visible crystal faces. The spiral/ridged form suggests shell rather than a crystalline mineral.

Formation & geological history

Likely formed as a marine mollusk shell and preserved through burial, mineral replacement, or recrystallization in sedimentary rock. Its geological age cannot be determined from the photograph.

Uses & applications

Primarily a teaching, collecting, and micropaleontology specimen; not suitable for construction or jewelry unless incorporated into decorative material.

Geological facts

Shell fossils commonly retain original sculptural details even after partial mineralization. A drop of dilute hydrochloric acid would typically produce effervescence if calcitic, though aragonite may have been altered.

Field identification & locations

Common in marine limestones, beach deposits, and sedimentary exposures worldwide; inspect for a complete spiral or hinge to identify it more precisely. The scale and apparent texture support a fossil shell fragment.