...The grey areas made it look like swirls of quarts and for some reason there seems to be no depth perception to the pic so it looks like it could pass for a button (versus a sphere shape). But Ok, now I know.
There's not even a size for the crotal? Wow. The square shank may be the key to figuring maker. Idk. Figured there might be one initial on the bottom at least with a size.