J.R.R. Tolkien’s works do not give the metal of Bilbo’s sword Sting a specific name.
Sting is a short sword found by Bilbo Baggins in a troll hoard during The Hobbit. It was made by Elves in the First Age and later acquired by Bilbo, who gives it its name after it glows blue in the presence of Orcs. Bilbo eventually passes the weapon to Frodo.
Tolkien describes Sting as a blade of unusual quality, but he does not identify its material as mithril or any other named metal. This is an important distinction because readers sometimes infer a material from the sword’s age, craftsmanship, or magical properties.
Sting’s blue glow is a warning feature shared with certain ancient Elvish blades. Its small size makes it suitable for a Hobbit, while its sharpness and history make it valuable in dangerous encounters. The sword is also used by Samwise Gamgee after Frodo is captured by the Orcs in Mordor.