Cold Iron

With patience, the right chemicals, and a back you don't mind breaking, it is possible to form iron into weapons and armor without it ever touching the heat of the forge. Physically speaking, this is pointless, but it is not the physics that matters...it is the magic.

Cold iron has power over magic--specifically, it absorbs and deflects it. Cold iron weapons can ignore and dispel magical protections, while cold iron armor protects its wearer against magic more aptly than ordinary steel.