Stygium

Stygium as a Cloaking Device
Stygium was a crystal only found on Aeten II. The Galactic Republic, in 22 BBY, passed a law controlling the trade of stygium, as it was a crystal that, when used properly, could entirely cloak a vehicle. In the Galactic Republic's early years these devices were common, since Aeten II held an abundance of them. These vehicles included the Scimitar, Darth Maul's flagship, which carried an array of stygium crystals in its long prow. During the events from the capture of the Tantive IV to the Battle of Endor, Grand Admiral Martio Batch sent an Empire superweapon to Aeten II, the Tarkin. There, the Tarkin blew open the planet to reveal its stygium core. Using the crystals and the original stygium implementation, he started the Phantom TIE project. However, saboteurs from the Rebel Alliance destroyed the project and Batch fled. The stygium crystal cloakings disappeared after the creation of the New Republic, although they were still available from Aeten II.

Appearances

 * Star Wars Episode I: The Phantom Menace