Rarely, lumps of pure iron is found that appear to have fallen from the sky. The lumps fall more often in mountainous terrain, or at least that is where it is easiest to find. This dark, almost black, form of iron is very hard to forge. Only the dwarven smiths of the mountain tribes have mastered the methods for shaping it into some some of the sharpest blades in existence. Items made from sky iron are icy cold to the touch, even to the point of frosting up on a warm summer day.
The elven nobles of House Silionbar has a sky iron blade as their eponymous heirloom, and the ancient mark of office for the thane of the Grungiburgi dwarven tribe, the Runewarden, is made from sky iron.
Sky iron costs about 2500gp per pound.