Kamacite

Kamacite is a variety of iron. It is an alloy of iron and nickel, usually in the proportions of 90:10 to 95:5 although impurities such as cobalt or carbon may be present. On the surface of Earth, it occurs naturally only in meteorites. It has a metallic luster, is gray and has no clear cleavage although the structure is isometric-hexoctahedral. Its density is around 8 g/cm³ and its hardness is 4 on the Mohs scale. It is also sometimes called balkeneisen.