Pyrite Sand Dollar - Are Some Actually Real Fossils Or Are All Of Them Are Pseudo-Fossils?

[AJ Plai]

Just would like to know that are all pyrite sand dollars pseudo-fossils? Or

there are actually sand dollar fossils that can become pyritized and they

are confused with marcasite crystal or pyrite sun due to their similarity?

If that's the case, how would you be able to tell the difference from the two?

[THobern]

I think that they are just pyrite suns, which should lack pentaradial symmetry.

[mikeymig]

I agree. They are mineral and not fossils. Some people market them as fossil sand dollars and I even saw one person try to say they were fossil jellyfish. Pyrite can form in a variety of shapes and the thin cracks that occur in this black shale cause the pyrite to grow or form into a disc.

Mikey

[Kosmoceras]

Here is an example of one I found, not an echinoid.