Iron Pyrite Sun, also known as, Pyrite Dollars, Miner’s Dollars, or even Sun Dollars. They may look like fossilized plants, but the crystal structures actually formed deep underground under great pressure about 350 million years ago. These round disks sometimes occur between seams of coal and may be found when coal is mined.  Although pyrite is quite common worldwide, the disk form is virtually unique to Illinois.

Pyrite commonly forms cubes, octahedrons, pyritohedrons or some combinations of these forms. All pyrite is FeS2 with the same internal arrangement of iron and sulfur atoms. Why then, should pyrite crystals take on different shapes? All these forms reflect the same internal atomic symmetry, so the reasons must involve the conditions under which the pyrite forms. These are such things as temperature, pressure, acidity, and the composition of the fluids from which the pyrite grew.

The Iron Pyrite in this collection was sourced from many locations, under different conditions giving us the different shapes and formations you see before you.