Many important metal ores are sulfides. Significant examples include: argentite (silver sulfide), cinnabar (mercury sulfide), galena (lead sulfide),  molybdenite (molybdenum sulfide), pentlandite (nickel sulfide), realgar (arsenic sulfide), and  stibnite (antimony), sphalerite (zinc sulfide), and  pyrite (iron disulfide), and chalcopyrite (iron-copper sulfide). This sulfide minerals recorded information (like isotopes) of their surrounding environment during their formation. Scientists use these minerals to study environments in the deep sea or in the Earth's past.