Origin: Pierre Shale Formation, Elk Creek, South Dakota
These extinct mollusks thrived 73 million years ago in warm oceans, using their shells to filter food from seawater. Pearls have been discovered within their fossilized shells. Preserved in protective concretions, these fossils display colorful iridescence. Their formation is linked to ancient meteorite impacts and tsunamis that shaped the seafloor into fossilized mud balls. These unique pieces are a stunning reminder of Earth’s ancient marine life and geological history.
