Mithril is the fictional metal used to make Bilbo’s and Frodo’s famous mail coat in J.R.R. Tolkien’s world.
Bilbo receives the mithril coat during the events of The Hobbit after the Dwarves discover treasure in the Lonely Mountain. He later gives it to Frodo, who wears it during The Lord of the Rings. The coat is light but exceptionally strong, and it protects Frodo from a spear thrust in Moria.
Mithril is described as a rare metal associated especially with Khazad-dûm, the Dwarven realm known in the Common Tongue as Moria. Its value becomes enormous after the Dwarves awaken the Balrog and mining in Moria ends. The name is from Sindarin and is commonly explained as meaning “grey glitter.”
Mithril is not the same as the Silmarils, the Rings of Power, or the Dwarves’ necklace Nauglamír. Those objects are related to other legends and materials, while the mail coat is the story’s clearest example of mithril craftsmanship.