fossil

Turritella Agate

Elimia tenera silicified fossiliferous chalcedony

Hardness: 6.5-7 (Mohs). Color: Dark brown to black matrix with white or cream snail shells. Luster: Vitreous to waxy when polished. Crystal Structure: Hexagonal (Microcrystalline). Cleavage: None.

Hardness: 6
Color: Dark brown to black matrix with white or cream snail shells
Luster: Vitreous to waxy when polished

Identified July 9, 2026More fossil →

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Physical properties

Hardness: 6.5-7 (Mohs). Color: Dark brown to black matrix with white or cream snail shells. Luster: Vitreous to waxy when polished. Crystal Structure: Hexagonal (Microcrystalline). Cleavage: None.

Formation & geological history

Formed during the Eocene Epoch (approx. 50 million years ago) in the Green River Formation of Wyoming. It is a silicified fossiliferous limestone where the shells of freshwater snails were replaced by chalcedony.

Uses & applications

Polished for jewelry (cabochons), used in lapidary art, spiritual/healing collections, and as educational fossil specimens.

Geological facts

Despite its common name, the fossils are not actually from the marine genus Turritella, but rather from the freshwater snail genus Elimia (formerly Goniobasis). It represents an ancient lake environment.

Field identification & locations

Identify by the high-contrast spiral shell patterns embedded in a dark silicious matrix. Found primarily in the Bridger Formation around the Green River in Wyoming, USA.

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