Brilliantly Iridescent, 5.1" Baculites Section - South Dakota

This is a 5.1" long section of a large Baculites fossil from the Pierre Shale of South Dakota. It has a brilliant iridescence to it with shines with bright purple and green coloration.

Baculites ("walking stick rock") is an extinct cephalopod genus with a nearly straight shell. The matrix it is preserved in has been sculpted so that it stands up freely, making for a very aesthetic display. It's approximately 75 million years old, and comes from a time when a shallow sea covered much of South Dakota.