aprox 161 graMS Cathedral Pyrite One of the rare forms of pyrite is called cathedral pyrite and is found in the Leadville silver mines. The cube faces have prism growths shaped like the curving pointed windows of a Gothic cathedral. Note, too, that some of the pyrite crystals from Leadville, Colorado, contain bits of gold in them. For serious pyrite collectors, there are other forms the iron disulfide can take. It often develops in long wire-like tangled growths. It has also been mined as perfect spherical balls of pyrite with thin horizontal rows of tiny crystals completely encircling the sphere.

Coal forms from the rotting vegetation of earlier plant life in a huge swamp area. Slowly the plant life died, was buried and compressed until all that was left of the plant matter was the plant carbon and related chemicals like hydrogen sulfide, the by-product of bacteria in the watery mix. The iron and sulfur in this chemical mix combined to form the pyrite crystals. The problem is the space where the pyrite crystals form restricts growth in a two-dimension space, so crystal growth is limited to forming long radiating crystals that just fit the space available and grew in four directions instead of six.