Nak

Nak was an exotic type of metal found rarely throughout the world. It's strange properties and extreme rarity made it quite valuable to many cultures, especially that of the Dwarves.

Etymology
Nak is the ancient Dwarvish shortened name for the metal, derived from the full word of nak-hur, simply meaning the metal. In everyday speech, other metals are usually referred to by their proper names in order to avoid confusion. Nak is usually referred to with strength and emphasis, and almost always after the word the is used to introduce it.

Physical properties
Nak was noted as an extremely and volatile substance that was only found within the bowels of volcanoes. The nature of nak meant that it was strong enough to withstand powerful pressures such as those from the underground fissures that created it, which made it the one building material that it was suitable for the famed gates and walls of Dwarven cities. Pure nak was roughly forty times as strong as steel when reinforced, and when combined with other metals into an alloy, could