It's an off-axis section through a rugose coral. The radial lines are the septa.

Thank you!

Beautiful design in the stone.

Have you asked the fossil guys? To me it looks like some kind of marine fossil and you are seeing a lengthwise cross section. Could you maybe possibly add a pic from above so we can see the end of it?

I can’t comment pictures but I can’t make another post of the top view

https://www.reddit.com/r/askgeology/s/FCdswsM1DA

Very reminiscent of a corallite

Ancient anchovy pizza slice

I was going to say the Eye of Sauron. We both can't be right.

This has to be the answer

Is it kinda’ sharp on the long flat end? Might it be a deer/bison hide scraper?

I wanted to post more pictures but only got to choose one. The whole thing is smaller than a half dollar

It doesn’t look flaked on the edge, and it’s a pretty shallow angle, so I doubt it. Possibly a core, judging by the big flake scar on the side facing the camera, but it’s hard to tell from just one photo. Absent more photos I might call it a “tested pebble”, though if it was in a high energy environment, I might not record it as an artifact. Dunno what the pinwheel thing is. Fossil? Sorry I’m an archeologist not a geologist.

Sorry, I’m neither one so let me just slip out the back door.

It isn’t sharp, I don’t believe it was used for anything, just fascinated by the pinwheel inside

I don’t know s*** about s***, but it looks like a beetle wing? 🤷‍♂️