2.75" Perfect RAW Round Pyrite Sun Dollar , Illinois . Stand not included. Southern  mine Illinois.  No, a miner's dollar (or pyrite sun) is not a fossil, but a geological concretion. These, often found in Illinois coal mines, are radial, disk-shaped iron sulfide (

$Fe{S}_2$

) crystals formed under pressure 350 million years ago, not petrified, ancient organic matter