fossil

Fossilized Shell

Invertebrate fossil (Bivalvia or Brachiopoda)

Hardness varies by mineral replacement (often Mohs 3 to 5 for calcite/aragonite or 7 for quartz/silicification), grayish-purple coloration, dull to vitreous luster, amorphous to crystalline replacement structure.

Identified July 29, 2026More fossil →

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Physical properties

Formation & geological history

Formed through the process of permineralization or replacement where organic shell material is slowly replaced by minerals over thousands to millions of years in aquatic sedimentary environments.

Uses & applications

Used for educational purposes, fossil collecting, and occasionally in jewelry or decorative items.

Geological facts

Fossilized shells provide crucial evidence of ancient marine environments and past sea levels, helping scientists reconstruct prehistoric ecosystems.

Field identification & locations

Can be identified in the field by distinct growth lines, ribbed textures, and symmetry typical of bivalves or brachiopods, commonly found in sedimentary rock formations such as limestone, shale, and sandstone.

Other fossil specimens

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Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

fossil

Sedimentary Outcrop (Sandstone/Shale)

Sedimentary bedrock formation (variable composition)

sedimentary

Chert with Fossil Brachiopod

Microcrystalline Quartz (SiO2) with Calcitic Brachiopod inclusion

sedimentary

Fossilized Crinoid Stem in Limestone

Crinoidea (Class) in Calcium Carbonate (CaCO3) matrix

fossil

Fossiliferous Limestone

Limestone with embedded fossil cross-section

sedimentary

Fossiliferous Limestone with Crinoid stems

Limestone (CaCO3) containing Crinoidea fossils

sedimentary