Arsenopyrite is a mineral commonly found in ore deposits that contains arsenic and iron. Some common synonyms for arsenopyrite include mispickel, arsenical pyrite, and arseniferous pyrite. Other related minerals may include pyrite, chalcopyrite, and sphalerite. Arsenopyrite is often associated with gold deposits, and it can be used in the production of arsenic-based chemicals. Because of its toxicity, arsenopyrite must be handled with care. Understanding the various synonyms and related minerals associated with arsenopyrite can be helpful for those in the mining and chemical industries as well as those studying geology and mineralogy.