Mithril is the fictional metal used to make Frodo’s mail-shirt in J.R.R. Tolkien’s The Lord of the Rings.
Bilbo receives the small coat of mithril from Thorin’s treasure in The Hobbit and later gives it to Frodo. The shirt is extremely light but exceptionally strong, allowing Frodo to survive an otherwise fatal thrust during the struggle in Moria. Its value is enormous because mithril is rare and difficult to obtain.
The name comes from Tolkien’s invented Sindarin language and is commonly interpreted as meaning “grey glitter.” Mithril is associated particularly with Moria, where the Dwarves mined it before awakening the Balrog and abandoning the realm.
Mithril is sometimes confused with other special substances in Tolkien’s legendarium, such as galvorn, a dark metal described in First Age writings. The mithril coat is specifically a protective mail-shirt, not a sword or a general magical armor spell.