Doonium was a heavy metal primarily used in starship hull construction. It gave ships such as those in the Imperial Navy their characteristic white-gray color. Doonium was mined primarily from asteroids and other small planetoids. The Empire granted exclusive mining contracts to companies like Turlin Corp to provide the needed ore. One source for the metal was the mines of the Thrugii Asteroid Belt in the Socorro system. Other sources included Dor and Atraken.