The most common type of iron meteorite, containing 6–12% nickel. The meteorite that formed Meteor Crater was an octahedrite. In addition to having a greater nickel content than hexahedrites, octahedrites have an additional mineral, taenite, which is nickel-rich. Octahedrite meteorites have a structure which consists of plates of the mineral kamacite orientated parallel to the sides of an octahedron (hence their name), with the intervening spaces filled with taenite. This arrangement of the two minerals forms a Widmanstätten pattern. Octahedrites are classified according to the thickness of the kamacite plates (the band width). Coarse octahedrites have band widths of 1.5–3 mm; medium octahedrites have band widths of 0.5–1.5 mm; and fine octahedrites have band widths of 0.2–0.5 mm. Below a band width of 0.2 mm, three different types of octahedral structure are apparent. The finest octahedrites have band widths of less than 0.2 mm. The ataxites have spindles of kamacite rimmed with taenite which may intersect, but do not overlap. The plessitic octahedrites are transitional between finest octahedrites and ataxites.