Dark iron is an illustrious dark-grey metal of roughly the same weight as tempered steel. It only exists deep underground in areas with volcanic activity, where the formation of the metal is made possible by a combination of extreme pressure and heat. Dark iron is mined and industrialized by the denizens of the deep. Duergar were the first to discover the method of smelting and manipulating the metal, and guard its secrets closely. While possessing most of the properties attributed to ordinary iron, dark iron has the added property of rebuking heat and magical energies, preventing such effects from passing through it.