Mithril

A rare metal that is both light and strong, most famously used for armour.

Mithril is difficult to work with as it has a high melting point and becomes brittle if not cooled properly. Its rarity and difficulty of crafting make mithril armour very expensive. Additionally, the forging and working of mithril is a dwarven secret that no human has discovered yet, and that the dwarves guard carefully.

A chain mail of mithril is no more cumbersome than a set of heavy cloth, but as solid as the best steel.