What is Arsenopyrite

         Arsenopyrite is an iron arsenic sulfide mineral with a chemical composition of FeAsS. It is the most abundant arsenic mineral and the primary ore of arsenic metal. In addition to being found in deposits that are large enough to be minable, arsenopyrite is widely distributed. However, it usually occurs in such small amounts and in such small particle sizes that it is easily overlooked. It is associated with other sulfide minerals in organic-rich sedimentary rocks, metamorphic rocks, and igneous rocks in many parts of the world.



  Much of the arsenopyrite that has been mined formed as a high-temperature mineral in hydrothermal veins. It is often mined, together with other metallic minerals, from veins that might contain gold, silver, lead, or tin. In these deposits arsenopyrite usually occurs in a granular massive form. It is often intergrown with other sulfide minerals such as chalcopyrite, galena, pyrrhotite, pyrite; precious metals such as gold and silver; or other minerals such as scheelite, cassiterite, and quartz.



  Arsenopyrite has also been mined from sulfide deposits formed by contact metamorphism. It is occasionally found in pegmatites. Well-formed crystals of arsenopyrite are most often found in pegmatites and in carbonate rocks that have been altered by contact metamorphism.