fossil
Turritella Agate / Fossiliferous Limestone
Elimia tenera in Chalcedony/Calcite Matrix
Hardness 6.5-7 (for agate matrix) or 3 (if limestone), dark gray to black matrix embedded with spiral snail shells, vitreous to dull luster, non-cleavage, density ~2.6 g/cm3.
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Physical properties
Hardness 6.5-7 (for agate matrix) or 3 (if limestone), dark gray to black matrix embedded with spiral snail shells, vitreous to dull luster, non-cleavage, density ~2.6 g/cm3.
Formation & geological history
Formed during the Eocene epoch (about 50 million years ago) in freshwater lake environments, primarily within the Green River Formation in Wyoming, USA, where ancient freshwater snail shells were petrified in silica-rich sediment.
Uses & applications
Popular among rockhounding enthusiasts and fossil collectors; used for making lapidary cabochons, jewelry, bookends, and educational rock collection sets.
Geological facts
Despite being commonly called 'Turritella Agate', the fossilized snails belong to the freshwater genus Elimia (or Goniobasis), not the marine genus Turritella.
Field identification & locations
Easily identified by the distinctive, high-spired, cone-shaped fossil snail shells preserved inside a dark matrix. Common in Wyoming's Green River Basin.
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