sedimentary

Fossilized Gastropod in Limestone

Gastropoda (Class) in Fossiliferous Limestone

Hardness: 3 (matrix) to 4 (fossil) on Mohs scale; Color: Tan, beige, or light gray; Luster: Dull/earthy; Crystal Structure: Amorphous fossil replacement often by calcite; Cleavage: None (conchoidal or irregular fracture)

Hardness: 3 (matrix) to 4 (fossil) on Mohs scale
Color: Tan, beige, or light gray
Luster: Dull/earthy

Identified June 2, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed during the lithification of marine sediments. The gastropod shell was buried in calcium carbonate-rich mud on the seafloor, which eventually hardened into limestone over millions of years. This specimen likely dates from the Paleozoic to Cenozoic eras depending on the specific locality.

Uses & applications

Primarily used as educational or decorative geological specimens; limestone is used in construction and cement manufacturing.

Geological facts

Gastropods are one of the most successful groups of mollusks. While the shell itself is gone, what you see is a 'steinkern' or internal cast, where sediment filled the spiral shell and hardened before the original shell material dissolved.

Field identification & locations

Identify in the field by looking for spiral or coiled patterns within sedimentary rock layers. Commonly found in ancient marine basins or road cuts through limestone formations. Collectors should look for sharp definition of the spiral whorls.

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