Chassigny is a Mars meteorite which fell on October 3, 1815 at about 8:00 am, in Chassigny, Haute-Marne, France. Its is an olivine cumulate rock consisting almost entirely of olivine with inter-cumulus pyroxene, feldspar, and oxides. Chassigny was the only known chassignite until NWA2737 was found in the Moroccan Sahara in northwest Africa. Chassigny is particularly important because, unlike most SNCs, it contains noble gas compositions different from the current Martian atmosphere. These differences are presumably due to its cumulate nature.