Ilum was an ice planet in the Unknown Regions of the Skyriver Galaxy, one of the main sources of the valuable Adegan crystals used in the construction of Jedi lightsabers. The caverns containing the crystals were long ago turned into a Jedi temple. Unlike the crystals of other planets, the crystals of Ilum were limited to blue and green in color.
Geographical Features[]
Ilum was a terrestrial astronomical body smaller than a dwarf planet. With a kyber crystalline core and a frigid climate, it was considered a planet despite its size. The planet was situated in the eponymous star system located in a part of the Unknown Regions known as the 7G sector. Ilum was an arctic world; nearly the entire planet was covered in ice and snow, and was therefore inhospitable to most species, though it was populated with non-sentient animals.
Hidden beneath Ilum's frigid surface was what came to be known as the Crystal Cave. Within the maze-like caves grew kyber crystals, which brought the Jedi Order to Ilum so they could harvest the crystals 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.
Also located beneath the surface of Ilum were geysers, formed by volcanic activity on the planet. These geysers warmed some bodies of water under the ice and their size or duration could change due to volcanic episodes or mineral deposition. Geological formations were also present in the caves of the planet, formed over billions of years by accumulated mineral matter, deposited from hydrothermal fluids
Alternate Versions[]
Filo Illum[]
The Jedi Order made certain to protect their version of Illum from the Empire with the support of the Alliance of Nations.
Viau Illum[]
The Illum of the Viau universe was taken over by the Galactic Empire corrupting and draining its resources dry as well as having destroyed entire parts of the planet's surface, as they were harvesting kyber crystals; the destruction was visible even from space. When Great Jedi Purge survivor Ahsoka Tano returned to the planet, she noted that there were at least two Star Destroyers and a mining ship in orbit around the planet. Chunks of the planet had been carved away, exposing the rock and magma that boiled up from the planet's core.
About a year after a year after the Jedi Purge, it was discovered from Palpatine-commissioned deep space expeditions of the Unknown Regions using ancient navigational routes found in the Jedi Temple, and quickly occupied and began strip-mining Ilum as part of a large-scale terraforming project;harvesting the small world's abundance of energy-focusing kyber crystals for the focusing arrays of the Death Stars' superlasers, thus revealing magma bubbling from Ilum's core. The entrance to the Jedi Temple was destroyed to allow access to the crystal caves, and a massive mining ship, as well as two Imperial Star Destroyers, stood watch over the planet to gain its riches. The Empire used geothermal energy from the planet's core to power their machinery and control the internal temperature of their industrial operations. Harmful byproducts were created as a result, causing destruction to Ilum's pristine ecosystem. Eventually, a large industrial equatorial trench, called the Imperial Trench, was realized over the planet as part of Imperial plans, replacing what were gaping cracks that struck into the planet core of kyber.
After his Master's lightsaber was severely damaged, Padawan Cal Kestis visited Ilum's crystal caves to find a kyber crystal and build a new lightsaber. Although he had problems with the Imperial garrison on the planet, he was successful in his mission and able to escape the planet.