Turritella Agate (Calligrapher Stone)

Physical Properties

Hardness: 6.5-7 (Mohs). Color: Dark brown to black matrix with yellowish-tan spiral snail fossils. Luster: Vitreous to waxy when polished. Structure: Cryptocrystalline. Cleavage: None (Conchoidal fracture). Specific gravity: 2.60-2.65.

Formation & Geological History

Formed during the Eocene epoch (approx. 50 million years ago) in the Green River Formation. It is created when freshwater snail shells (Elimia tenera) are replaced by silica (chalcedony) in a sedimentary environment.

Uses & Applications

Primarily used for lapidary work, jewelry (cabochons), interior decoration, and as a popular 'healing' or collecting stone in various metaphysical communities.

Geological Facts

Despite its trade name 'Turritella,' the fossils are actually of the freshwater genus Elimia, not the saltwater genus Turritella. This specific specimen is carved into an 'obelisk' or 'tower' shape.

Field Identification & Locations

Identify by the distinctive spiral snail shell patterns embedded in a dark siliceous matrix. It is most famously found in the Green River Formation of Wyoming, USA. Collectors should look for dense fossil concentrations.

Identified on: 4/18/2026

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