Turritella Agate is
actually a case of mistaken identity! When this fossiliferous
rock was first discovered in the famous Green River sedimentary
deposits of Wyoming, the high-spired fossil shells
were mistaken for
those of marine gastropods (snails) in the genus Turritella.
By the time it was determined that they actually belong to a
gastropod species called Elimia tenera,
the incorrect name
had already caught on among gemstone and lapidary enthusiasts.
million years ago, during the Eocene
epoch, rains falling
on the Rocky Mountains
region filled many intermountain basins
with freshwater lakes.
Abundant plants and algae grew around
these lakes, creating a rich food source for Elimia
tenera. When these prolific snails died and fell to the lake
bottoms, great numbers of their shells were buried in the sediments
washing down the mountain slopes. Over time, silica-laden
groundwater moved through the deposits and precipitated
empty shell cavities and the spaces between the shells, forming the
chalcedony that today is (inaccurately) called Turritella
Agate (or should we say, Elimia Agate?)
polishes nicely and is often cut
into cabochons or slabs for jewelry,
belt buckles, and other lapidary
craft items. The specimens
on this page fit smoothly into your hand, and are a fun, easy
way to carry fossils in your pocket!