Black Iron

Named for it's color, weight and resilience, black iron isn't actually iron. It is an alloy of iron amount other unknown metals. Modern science has yet to recreate the alloy in a lab, however, metallurgists have found ways to melt black iron down and reforge it. Recently, it has started to be used in the construction of Eijmar ships. They band it to the bottom of the hull, since black iron can withstand an auramere eruption.