Thor's hammer, Mjolnir, was forged by Dwarven blacksmiths of the Asgardian metal uru. Not having any uru available to me I created my version of Mjolnir out of Hard Maple and Red Oak. The central head motif measures 4"x4" so it does have enough "heft" to live up to the charge that "Whosoever holds this hammer, if he be worthy, shall possess the power of Thor."