sedimentary

Gastropod Fossil (Snail Internal Mold)

Gastropoda; internal mold (steinkern), often composed of Calcium Carbonate (CaCO3) or Silica (SiO2)

AI-generated identification · may be incorrect

Hardness: 3-4 (if calcified) or 7 (if silicified); Color: tan, grey, or light brown; Luster: dull to earthy; Structure: planispiral or helicoid coiled shell shape; Cleavage: none (fractures irregularly)

Hardness: 3-4 (if calcified) or 7 (if silicified)
Color: tan, grey, or light brown
Luster: dull to earthy

Identified March 20, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when a snail shell fills with fine sediment or minerals after death. The original shell eventually dissolves, leaving a solid stone cast of the interior. These can range from the Paleozoic to the Cenozoic era, commonly found in limestone or shale beds.

Uses & applications

Primarily used for geological study, education, fossil collecting, and occasionally as decorative pieces in jewelry or 'curiosity' displays.

Geological facts

These specific types of fossils are called 'steinkerns,' a German word meaning 'stone hearts.' They do not show the surface texture of the original shell, but rather an exact replica of the space the animal lived in.

Field identification & locations

Identify by looking for the distinct 'cinnamon roll' or spiral pattern that tapers to a point (apex). Commonly found in sedimentary outcrops, riverbeds, and limestone quarries. Collectors should look for intact coils without heavy erosion.