Tritanium

Tritanium is an ore that can be found on many planets across the galaxy and are used by many species for construction purposes. For example, the Federation and the Axanarri use tritanium for the hulls of their starships. (TNG episode: "Where Silence Has Lease", VOY episode: "Repentance", and ENT episode: "Fight or Flight").

Tritanium and tritanium compounds are also used for certain projectile weapons, such as the TR-116 rifle which was in development by Starfleet in the late 24th century. (DS9 episode: "Field of Fire").