11. Aznalcollar Mines used the liquid to clean pyrites after mining. 12. Soil may contain iron sulfide as pyrite or calcium sulfate as gypsum. 13. Pyrite and amorphous iron sulfide along with carbon produce the black coloration.14. It commonly contains or is associated with grains of pyrite . 15. Gold and arsenic occur as a coupled substitution in the pyrite structure. 16. However, there are limonite pseudomorphs after other minerals such as pyrite . 17. Other mineral deposits are silver, copper, pyrite , and limestone. 18. This reaction between iron and sulfides forms pyrite ( FeS 2 ). 19. Ore minerals include pyrite , chalcopyrite, sphalerite and galena. 20. Nodular lumps of pyrite and crystals of septarian concretions are also common.
