Ilum Ilum was a snow - covered planet located in the 7G sector of the Unknown Regions , within the Ilum system . In the system , Ilum was fifth from its parent star Asar , a blue dwarf , located roughly equidistant from Asar and the system ' s cometary cloud . Ilum had been utilized by the Jedi Order for the Gathering , a rite of passage in which Jedi youngling s must find and harvest kyber crystal s for their lightsaber s , for thousands of standard year s . Description . The planet Ilum was situated in the Ilum system , a star system located in a part of the Unknown Regions known as the 7G sector . Ilum was an arctic world ; that is , the entire planet was covered in ice and snow , and was therefore inhospitable to most species . Hidden beneath Ilum ' s frigid surface was what came to be known as the Crystal Cave . Within the maze - like crystal cave s grew kyber crystal s , which brought the Jedi Order to Ilum so they could harvest the crystal s in a rite of passage known as the Gathering , in which Jedi initiates harvested their crystals by attuning themselves to the Force . As such , Ilum was a holy site for the Jedi Order for centuries . By 18 BBY , the Empire had already corrupted Ilum , draining its resources dry as well as having destroyed entire parts of the planet ' s surface , as they were harvesting kyber crystals for the Death Star ; the destruction was visible even from space . When Jedi Purge survivor Ahsoka Tano returned to the planet , she noted that there were at least two Star Destroyer s and a mining ship in orbit around the planet . Chunks of the planet had been carved away , exposing the rock and lava that boiled up from the planet ' s core . History . Discovery . Ilum ' s recorded history began tens of thousands of years before the Galactic Empire ' s creation . A Jedi scout performed Force - assisted hyperspace navigation through hyperspace route s , taking her to the Unknown Regions . She was drawn to a powerful resonance in the Force , which brought her to Ilum . The scout reported that Ilum was devoid of any sentient life , but was rich with non - sentient animals . Jedi uses . Survey teams were sent out later , and ultimately discovered the vast quantity of naturally - forming kyber crystal s such as pontite and mephite . The Jedi Order ' s High Council dispatched scholar s , artisan s and warriors to secure the planet . The Council decided that the planet should be kept secret to the galaxy at large . Hyperspace surveyor s mapped out an uninterrupted hyperspace route from the Core World of Metellos directly to Ilum , and was incredibly complex . Eventually , all mentions of Ilum were deleted and it was kept from local , sector - wide and galactic star map s . The Jedi Temple on Ilum remained the last sign of intelligent life on Ilum , but was almost entirely covered by ice . All other bases on Ilum were removed by the Jedi . Ilum became a bigger supplier of kyber crystals when other planets exhausted their supplies . Clone Wars . As was tradition , a group of Jedi youngling s would travel to Ilum to build their first lightsaber s , aboard the " Crucible " and escorted by a higher - ranked Jedi . In 20 BBY , one such Gathering took place in the midst of the Clone Wars . Padawan Ahsoka Tano escorted the youngling s Byph , Ganodi , Gungi , Katooni , Petro , and Zatt to the Crystal Cave , where Grand Master Yoda awaited their arrival . Each youngling endured different trials to retrieve their crystals . All of the younglings left Ilum aboard the " Crucible " , where they would be instructed by the architect droid Huyang on the construction of their lightsabers . Under the Empire . A year after the Gathering took place , the Galactic Empire was proclaimed . The Empire quickly began strip - mining Ilum , revealing magma bubbling from Ilum ' s core . The entrance to the Jedi Temple had been destroyed to allow access to the crystal cave s . A massive mining ship , as well as two Imperial Star Destroyer s stood watch over the planet to gain its riches . Inhabitants . Ilum was not home to a large amount of people , with just 5 , 200 sentient inhabitants . Of those 5 , 200 , 45 % were support crew , 30 % were temporary researchers , 20 % were military , and the remaining 5 % were other individuals living on - world . Locations . Ilum ' s main attraction was its Jedi temple , hidden beneath a large cliff of ice . Beneath that temple was the planet ' s massive complex of crystal caves where a vast quantity of kyber crystals could be found , and the site of the Gathering . The remainder of Ilum ' s surface was barren , save for canyons and mountains .