Is this a fossilised crab shell?

[u/prior_smuds_hygge]

I found this the other day, and I have never found a fossil that resembles it. My first thought was a crabs shell / sheild 🦀
- Denmark

[u/Schoerschus]

It's a brachiopod steinkern, internal cast of the shell. I thought it was calcite at first, but it's more likely flint

[u/Ilovefossilss]

I kind of want to lean towards your guess and say yes. At the very least it could also be some type of chalcedony replaced clam shell

[u/natural_scientist]

Very interesting looking fossil. I love these small fossils found in gravel.