This is a fantastic educational block of a variety of species of Cretaceous ammonites from the Pierre Shale Formation of South Dakota, USA. Scattered throughout the host rock are numerous layers of gem-grade iridescent shell nacre, some in the prized RED hues along with other colors. There's a stunning iridescent Sphenodiscus sp. ammonite on one end with incredible interior detail. A number of other species can be seen, all sporting a colorful nacre from their original preserved shells!
Keep as it is for a fascinating conversation display specimen. It could even be prepared further to fully expose the color shell layers. Rare internal leaf-pattern anatomy is plainly visible with some ammonites showing internal hollow detail! Perfect to accompany any advanced fossil marine life collection as well as a stunning and highly unique interior design fossil of pure natural history!