Iron meteorites are one of the most durable and easiest to recognize of all the meteorites, but only one in ten meteorites that fall from the sky is of theiron variety. The other 90% are stone meteorites. Iron meteorites are fragments of the once-molten metal core of an asteroid or demolished moon probably from the asteroid belt. As these moons cooled, their cores crystallized and through later collisions, were destroyed. Chemically, they are an alloy, or combination, of iron (Fe) and nickel (Ni), of approximately the same density and hardness as a blacksmith's anvil.