| The central and western United States have a similarly diverse array of pyrrhotite occurrences. |
| This rock is a dark gray schistose rock containing radiating aggregates of cummingtonite and occasionally pyrrhotite. |
| Other sulfides, including pyrite, marcasite, chalcopyrite, and pyrrhotite, are occasionally found as well. |
| Microcrystals of pyrrhotite, goethite, pyrite, galena, and calcite are found on the dumps. |
| We have also seen several specimens in which pyrite has replaced a hexagonal mineral that was probably pyrrhotite. |
| We have not yet found any unaltered material to verify that the original mineral was pyrrhotite, as claimed by Brush. |
