Kamacite is an
alloy of
iron and
nickel, which is found on earth only in
meteorites. The proportion iron:nickel is between 90:10 to 95:5; small quantities of other elements, such as
cobalt or
carbon may also be present. The mineral 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.