Before revision: Occurrence Widmanstätten pattern showing the two forms of nickel-iron , kamacite and taenite, in an octahedrite meteorite On Earth, nickel occurs most often in combination with sulfur and iron in pentlandite, with sulfur in millerite, with arsenic in the mineral nickeline, and with arsenic and sulfur in nickel galena.National Pollutant Inventory – Nickel and compounds Fact Sheet .
After revision: Occurrence Widmanstätten pattern showing the two forms of nickel–iron , kamacite and taenite, in an octahedrite meteorite On Earth, nickel occurs most often in combination with sulfur and iron in pentlandite, with sulfur in millerite, with arsenic in the mineral nickeline, and with arsenic and sulfur in nickel galena.National Pollutant Inventory – Nickel and compounds Fact Sheet .