Pyrite Sun, collected from Sparta, Illinois
Unlike with the solar eclipse happening this Saturday, there is no need to avert your eyes from this sun! This is a pyrite sun, sometimes also called a pyrite dollar or sun dollar. These mineral specimens have an unusual formation which displays striations radiating out from the center like rays of the sun. And although pyrite is found pretty much everywhere, the sun disk formation is essentially unique to Illinois!
Some people used to think that pyrite suns were fossilized plants, but we now know that they are crystal structures that formed deep underground under enormous pressure about 350 million years ago. It is common to find these mineral disks about 300 feet below ground between seams of coal when coal is mined. The radiating pattern is a result of the compressed growth of the pyrite (also known by many as fool’s gold) between sheets of anthracite coal shale. The resulting formation are quite breathtaking!
See more Artifacts of the Week
