Mineral almost identical to Arsenopyrite, but contains antimony in place of the arsenic. Its chemical formula is FeSbS. Gudmundite is very similar in physical properties to Arsenopyrite, and is sometimes wrongly classified as a variety of it, when in fact it is scientifically a separate mineral species. It is found in Gudmundstorp, Sala, Sweden, and Ilimaussaq, Greenland.
See the full Arsenopyrite page for properties, photos, and additional varieties.
