sedimentary
Gastropod Fossil (Snail Internal Cast)
Class Gastropoda (Steinkern)
Hardness: 3-4 (calcite-based); Color: Tan, beige, or light brown; Luster: Dull or earthy; Crystal structure: Amorphous or microcrystalline calcite; Cleavage: None; Specific gravity: Approx 2.6-2.8
- Hardness
- 3-4 (calcite-based)
- Color
- Tan, beige, or light brown
- Luster
- Dull or earthy
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Physical properties
Hardness: 3-4 (calcite-based); Color: Tan, beige, or light brown; Luster: Dull or earthy; Crystal structure: Amorphous or microcrystalline calcite; Cleavage: None; Specific gravity: Approx 2.6-2.8
Formation & geological history
Formed through permineralization or as a 'steinkern' (internal cast) where sediment fills a shell that later dissolves. Usually Carboniferous to Cretaceous period, found in ancient marine or freshwater sedimentary layers.
Uses & applications
Primarily for geological study, educational teaching tools, and private fossil collections.
Geological facts
Gastropods are one of the few groups that successfully live in marine, freshwater, and terrestrial environments. Internal casts like this are often called 'Murchisonia' or 'Maclurites' depending on the specific genus and age.
Field identification & locations
Look for a coiled or spiral shape with visible whorls. Commonly found in limestone outcrops, road cuts, and riverbeds. Collectors should look for distinct sutures between the whorls.
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