During the course of an investigation of the equilibrium relationships of Fe3O4, Fe2O3, and oxygen we had occasion to use some of the very pure magnetite from the Lovers’ Pit at Mineville, N.Y. This material occurs as granular magnetite and faceted crystals. It is remarkable for the size of the masses with uniform orientation, and for the perfection of a system of intersecting planes parallel to the octahedral directions of the magnetite, along which it separates when broken. The faces of the crystals are marked by striae where these separation planes outcrop. A close inspection shows that there are other separation planes and striae in addition to the octahedral ones.