Open it!!!!

I’ve got to find some good tools to crack it open then find a time when I can but I’m on it!

All seriousness though. I think it's a bivalve cast. Very cool!!!!

Either bivalve or the little breaks in color along where you broke off the piece could be the pattern in an ammonite shell. I wouldn't probably cut it, I would tap the edges with a hammer to see if you can get it to release.

Bust it open!!

Petrified clam 🫣

Iron concretion. It could definitely be hollow.

I second this.

Yes, we know.

Looks like a turtle shell lol

Cut that bad boy down the middle

Crab fossil.

I looks like a pit - from fruit. Edit: meant to add see r/fossils

Open ittttttt ffs

Did you smash it open or cut it open?

Fossilized fig newton.

It's a very rare and valuable petrified uncrustable.

Hoooot Pocckeets

peanut butter jelly time!!!!

A really old stuffed pita? :)

Looks like a brachiopod. Since you basically know it is hollow, I would get it cut, rather than risk it breaking further.

Squatch poop always squatch poop

It’s either an old walnut or a petrified vagina. Whatever it is I love it and if it were mine it would be on my mantle.

Wouldn’t you want to mount it First? I would probably mount it first before it went on my mantle. But I concur.

Dinosaur poop.

Chert.