I'm a iowa boy but that kinda reminds me of a sand dollar.
Thanks for the ideas! It's so weird that I can't find any info about the design. Is it supposed to be an 8 pointed "starburst" or just 8 lines arranged in a circle?I read through some of the theories offered when you first posted your find 2 years ago. Now that you've posted better pics, I'm thinking it could be either the decorative center portion of a brooch, part of furniture hardware or possibly from a horse rosette.