Variations in iron isotopic composition have been observed in meteorite samples from other planetary bodies. The Moon has variations in iron isotopes of 0.4‰ per atomic mass unit. Mars has very small isotope fractionation of 0.001 ± 0.006‰ per atomic mass unit. Vesta has iron fractionations of 0.010 ± 0.010‰ per atomic mass unit. The chondritic reservoir exhibits fractionations of 0.069 ± 0.010‰ per atomic mass unit. Isotopic variations observed on planetary bodies can help to constrain and better understand their formation and processes occurring in the early Solar System.