 The scholar of English literature Charles A. Huttar writes that "mithril" was the only mineral that Tolkien invented.He notes that in Tolkien's underworld, whether the caves at Helm's Deep or the mines of Moria, "beauty and terror [were] side by side".Greed for "mithril" could unleash the terror of the Balrog, by digging too far down into the dark realm, but at the same time, he writes, the metal was prized for both its beauty and its usefulness, yielding the best armour.