Rarest does not always mean useful: Francium and friends Not every metal that is scarce in nature ends up driving a global industry. Francium is a perfect example, often cited as the rarest metal in ...

For people so in touch with the mountains, it’s exciting to discover an entirely new ore. Durin’s Folk have only just discovered the “grey glitter,” the dwarven name for Mithril on The Rings of Power.