Found this on the beach, it definitely was a shell at one point. Looks to have little crystals inside. Is there a name for something like this? : r/ fossils
Fossil / Fossilized Muricidae-Murex You Name Special mur53 : Southern Arrow, Fossil Shells From Southern Arrow For Sale
Unraveling How an Extinct Mollusk Got Its Strange Shell - The New York Times
Fossils Information | Types Of Fossils
Common fossils to find | Coast | National Trust
KGS Pub. Inf. Circ. 24--Invertebrate Fossils of Kansas