Blastoid 57be4d5f38af896246e9d619e11b02dc With their graceful body lines

With their graceful body lines one can understand why these interesting yet bizarre creatures have been nicknamed "The Butterflies of the Sea"

Trilobite appx: ~2" Matrix size varies

though there are several distinct differences

The crystals are Pleochroism

Stingrays are a dimorphic

Blastoid 57be4d5f38af896246e9d619e11b02dc With their graceful body linesThe oldest blastoids lived about 425 million years ago. The animals survived until the Permian Period, about 260 million years ago, when they became extinct. Blastoids look much like small hickory nuts. They most commonly are found in the river cliffs and stream banks of western and southwestern Illinois, especially in Randolph County, and in southern Illinois near the Ohio River.