Search

Geologists know iron sulfide as a silvery-yellow to bronze-yellow, typically magnetic, sulfide mineral, whereas collectors who are unfamiliar with it might be forgiven for assuming that it's a hexagonal pyrite. Most pyrrhotite is actually monoclinic, with at least seven polymorphs that generally relate to the relative abundances of iron and sulfur because the mineral has no absolutely set composition. Pyrrhotite is metallic and opaque, varying in color from silvery-yellow to bronze-yellow. Pyrrhotite is common as an accessory ore mineral in a large number of Colorado ore deposits but has been reported as crystals from only the Eagle mine at Gilman, Eagle County, and from the Patch mine, Gilpin County, where curved and distorted pseudohexagonal crystals to 5 cm across have been completely replaced by granular pyrite.