Everyone is familiar with iron sulfide--it is pyrite, Fe[S.sub.2], fool's gold, brassy cubes, right? Well, file story of iron sulfides is far more complicated than simply that of pyrite, a mineral with which some are all too familiar. There are several other compositions and crystallographic variations on the iron sulfide theme that merit consideration. For instance, everyone with a technical interest in meteorites is familiar with troilite (FeS). Most economic geologists, and those ...