Purification was the process by which a corrupted kyber crystal was healed of the dark side's taint. It was the reversal of the bleeding process. A kyber crystal that had been cleansed in this manner would typically turn from red to white, and would form a powerful bond with the Force-sensitive individual who performed the ritual.
Luke Skywalker fails to purify a bled kyber crystal.
In order to purify a corrupted kyber crystal, a Force-sensitive individual had to form a bond, not only with the crystal, but also with the darksider who had bled it. Only by empathizing with them, and understanding what led them to the dark side in the first place, could one undo the damage that they had done to the crystal. To accomplish this, they would enter a trance-like state, in which they could communicate with the crystal, learning its history, as well as that of the one who bled it. Once this was accomplished, the would-be healer would attempt to impart their own positive emotions, such as joy and hope, to the crystal, causing it to "unlearn" the pain of its previous owner. If performed successfully, the healer would emerge from their trance profoundly changed by the experience, and the once-red crystal would glow a brilliant white.
However, just as a kyber crystal could defend itself from being bled, a corrupted kyber could fend off the efforts of a prospective savior by projecting dark-side visions and hallucinations into their mind, unbalancing them, and causing them to emerge from their trance in defeat, the crystal remaining bled.
The Togruta Jedi Jora Malli purified a bled kyber crystal during her career.
In the aftermath of the defeat of the Sith, the galaxy became littered with bled kyber crystals, taken from the sabers of slain Dark Lords and their followers. To counter this, the Fallanassi practiced and perfected the art of purification. The light-side-aligned religion formed a long-standing agreement with the Jedi Order whereby they would purify any kyber crystals defiled by the Sith that they came across. The Fallanassi also passed the lore on how to perform the cleansing ritual down through the generations, keeping the knowledge alive.
The Togruta Jedi Master Jora Malli unearthed an ancient Sith lightspear during her career. Curious about how the purification process worked, Malli removed the scarlet crystal from the spear and purified it, albeit solely as an academic exercise. To her surprise, however, Malli found that the newly cleansed crystal had developed a strong affinity for her, and chose to install it in her own lightsaber, which made the blade white.
During the New Republic Era, after Luke Skywalker helped a woman named Komat escape from the Acolytes of the Beyond—which she was part of—he purified the kyber crystal of her lightsaber, leaving the blade white, thus symbolizing the purging of evil from her soul and mind.
Purification first appeared in the 2016 novel Ahsoka, written by E. K. Johnston; however, the process remained unnamed until the 2021 novel The High Republic: Light of the Jedi, written by Charles Soule. Purification made its first onscreen appearance in "Aau's Song," an episode from the second volume of the non-canon anthology series Star Wars: Visions, which was released on May 4, 2023.
In the Star Wars Legends continuity, Jaden Korr changed a red synthetic lightsaber crystal into a yellow one. He later used this for his third lightsaber. The process was called cleansing.
Purification in "Aau's Song"
In the episode "Aau's Song," Aau, a Force-sensitive member of the Korban species, purifies an entire mountain of bled kyber crystals by singing to them, the beauty and harmony of her voice driving the dark side from the crystals. As in canon, the process turned the crystals from crimson to white.
- Star Wars: Visions — "Aau's Song"
- Star Wars: Dawn of Rebellion: The Visual Guide