Iodyrite

Iodyrite from Tonopah, Nevada, is one of those minerals that has a lot more going on than its simple appearance. Tonopah is famous for its silver mines, and iodyrite formed in the oxidized parts of those deposits alongside other silver halides. The Mizpah Mine is one of the classic places for it.

The crystals are usually a pale to bright yellow and can occur on quartz. Tonopah iodyrite is especially interesting because some crystals show a distinctive hemimorphic shape, which made specimens from this locality important to early mineralogists studying crystal symmetry. This is also a type locality.