Diburnium
Diburnium is a metallic element with phaser-resistant qualities. ()

History
An abandoned Kalandan outpost was built on an artificial planet composed primarily of a diburnium-osmium alloy. Attempts to cut through the surface with hand phasers had little effect. ()

Kelvans used a material similar to diburnium, though much denser, in security applications. Prison door bars and a Kelvan field projector casing were fashioned from the substance. Spock doubted if phaser fire could disturb its molecular structure. ()

Diburnium levels were an element in the deflector shielding utilized by Starfleet  starships in the 2250s in the alternate reality. (, display graphic )

See also 
 Triburnium
 Tetraburnium

External link
 

Materials

ja:ダイバーニウム