Ardanium was a mineral that grew stronger in the presence of radiation, making it incredibly useful in the construction of fuel cells for large starships. Ardanium also had medical applications, but the material's primary use in fuel cells made it highly valuable. The discovery of an ardanium reserve on the planet of Questal around 3 BBY led to the Ardanium Rush, in which thousands of entrepreneurs and miners traveled to Questal in search of the mineral.
Ardanium was a type of mineral that, when refined, had the unique property of growing stronger in the presence of radiation. That made ardanium especially useful in the construction of fuel cells, as a millimeter-thin coating of ardanium allowed the Galactic Empire to fashion fuel cells and engines that could be used in the construction of Super Star Destroyers. Ardanium also had medical applications, as the xenopathologist Archiban Kimble used the mineral in conjunction with accellerite and cyanogen silicate to develop a cure for a rare flesh-eating disease. Ardanium II was a material with similar properties to ardanium, though it was only used on smaller fuel cells.
Ardanium was known to the galaxy by the time of the Cold War between the Galactic Republic and the Sith Empire, as Kimble was able to acquire a supply of ardanium for his research in finding a cure for the flesh-eating disease afflicting the Hutt Suudaa Nem'ro. Around 3 BBY, an agri-droid on the planet of Questal turned over a rock that was embedded with ardanium. Upon learning of this, Emperor Palpatine of the Galactic Empire realized that he could double the size of his fleet with the reserves on Questal, and entrepreneurs and miners began to arrive by the thousands in search of their fortunes. Prospectors in the capital of Gralleenya ravaged the countryside around the settlement, leaving behind the Waste—a lifeless territory scarred by empty pits and mines. The Ardanium Rush, as it came to be called, also drew criminal elements that established footholds on the planet, and Palpatine was forced to send Moff Bandor to restore order. Bandor halted the chaos with the support of the Imperial Military, though conflicts continued to break out as Questal's ardanium deposits were depleted over the next three years. When agents of the Rebel Alliance defeated Bandor, the Empire chose to abandon Questal, as very little ardanium remained.
Ardanium was first mentioned in the 1990 West End Games roleplaying adventure The Game Chambers of Questal.
- The Complete Star Wars Encyclopedia, Vol. III