An exceptionally hard metal used in Federation starship hulls and equipment, first mentioned in the Original Series episode Obsession as many times harder than diamond.
Tritanium is one of the principal structural materials of Starfleet vessels, valued for its hardness and resistance to heat. Together with duranium it forms the hulls and frames of most Federation ships of the 23rd and 24th centuries.
It is first named in the Original Series episode Obsession, in which a survey of Argus X finds deposits of the ore and Spock notes that it is more than twenty times as hard as diamond.
From The Next Generation onwards tritanium is mentioned constantly: in bulkheads, shuttle hulls and tools, and as a benchmark for what a weapon can cut through. Deep Space Nine and Voyager use it the same way, and scans for tritanium traces are a routine means of finding wreckage.