Ancient sea urchins, small and spiny creatures, have existed for millennia. These echinoids first appeared in oceans 450 million years ago, where they fed on algae and sponges. Their flexible spines’ purpose was two-fold: to protect against predators and allow for the slow crawl towards the urchin’s next meal. Buried for millions of years, their fossils appear in many places where those oceans once were and have inspired human cultures for thousands of years as thunderstones from the gods, though their true origin is far older.

This bracelet features five fossil sea urchins from the genus Eupatagus, also known as the heart urchin. They first appeared in the fossil record at the beginning of the Cretaceous Period 145,000,000 years ago.