Cortosis / Legends Cortosis ore was a very rare , brittle , fibrous material that ' s conductive properties caused lightsabers to temporarily short out upon contact . This effect made cortosis a useful material for anti - lightsaber melee weapons , though with repeated strikes , a lightsaber could still cut through it . Cortosis , due to its energy resistant properties , was also resistant to blaster fire . Overview . Cortosis ore was used extensively in shadowtrooper armor , as well as the C - B3 cortosis battle droid s during the Clone Wars , and the Force - using group known as the Jensaarai . The cortosis used for this armor was smuggled out from Bespin ' s Cloud City . The walls of the Imperial Palace were also lined with cortosis ore . It was also used to strengthen starfighter and capital ship hulls , and was woven into body armor . Cortosis was expensive to mine because it was so rare and it had to be absolutely refined . Pure , unrefined , cortosis ore was for unexplained reasons , energized , killing anyone who touched it with his / her bare skin , even Hutts , who had energy - resistant enzymes in their sweat . Miners had to have filtering equipment , or else the cortosis particles would accumulate in their systems , causing hair loss , sickness , and eventually death . The substance was energy - resistant , meaning energy tools ( such as plasma torches ) were virtually useless . The brute force of hydraulic jacks were used to mine it , though it quickly wore the head of the jack to uselessness and its dust would clog the pistons . Pockets of highly - combustible lethane gas often formed near cortosis deposits . The most valuable type of cortosis was the purified variation . It was known as " Cortosis - Shield " , used by Roan Fel ' s Imperial Knights on their gauntlets . It was effective , and could short out a lightsaber for a short period of time . During the New Sith Wars , the Outer Rim Oreworks Company mined cortosis on Apatros . This was where future Dark Lord of the Sith Darth Bane was born and drilled cortosis for several years before fleeing to the Sith Army . The Jin ' ha mined cortosis on Obredaan . During the Invasion of Naboo , Trade Federation assassin droids used cortosis weapons . During the Clone Wars , the Jedi Council discovered that the Confederacy of Independent Systems was mining cortosis on Bal ' demnic , and dispatched a task force led by Halagad Ventor and Sha Koon to sabotage the operation . Large deposits of cortosis were also known to be on Duro and Katanos VII . Quinlan Vos wore a cortosis gauntlet on his left arm during the Clone Wars The Pau ' an Sith Lord , Darth Desolous , used a cortosis shield to block lightsaber attacks . Cad Bane used a cortosis slugthrower against Bolla Ropal to disable his lightsaber and capture him . Galak Fyyar had an entire powered suit of shielded battle armor created out of cortosis alloy . Riot stormtrooper s were armed with electrostaffs made with cortosis . Luke Skywalker and Mara Jade encountered a vein of cortosis on Nirauan while infiltrating the Hand of Thrawn during the Caamas Document Crisis . The Umbaran Nyss Nenn used twin vibroblades coated with cortosis in combat . However , they proved ineffective against the Force - sensitive clone Soldier , who kept contact between their weapons minimal by striking fast , which therefore only caused his lightsaber to spark . Roan Fel and all of his Imperial Knight s had pure cortosis gauntlets . Only lightsabers that used a special kind of lightsaber crystal mined on Mestare were immune to the effects of cortosis . Behind the scenes . Sources conflict over the nature of cortosis and its effects on lightsabers . Old Republic era sources , such as the " " and " " video games , treated the effects of cortosis weapons as merely energy - resistant and only capable of blocking lightsaber attacks ( though it may have been so due to gameplay mechanics , so cortosis blades wouldn ' t be too overpowered ) . This portrayal of cortosis is similar to that of phrik and Mandalorian iron . This is similar to the effect in " , " where assassin droids which carry cortosis blade s can block lightsabers but not shut them down . In the games " " and " " , when the player slashes a shadowtrooper with his / her lightsaber , the saber will not be deactivated however the damage is reduced and slight " exploding " effects appear around the area the armor was struck . In " " , a cortosis mine is described and cortosis is said to be incredibly dense and difficult to mine , but highly sought for its energy resistant properties that make it useful for weapons , armor , and in starship construction . In these sources , cortosis items and weapons are commonly used in the conflicts that make up the Dark Wars and the Sith civil war . This differs greatly from later - era portrayals , such as " I , Jedi " , in which cortosis is described as a brittle , highly malleable metal capable not only of blocking energy attacks , but of disabling lightsaber weapons when it comes into contact with them . Different types of cortosis have been named in various sources , such as cortosis alloy , purified cortosis , and cortosis weave , but no consistent explanation for the different portrayals has been provided by sources . The " shut - down " duration of time for the later - era portrayal of cortosis also varies in different sources . In " Vision of the Future " , when Luke Skywalker first encounters it , it deactivates his lightsaber , but he is able to reignite the blade immediately . In other depictions , however , including " " and the " " comic series , it renders lightsabers useless for several minutes .