Thontiin crystals were a type of kyber crystal that were rarely utilized as the core of a lightsaber during the time of the Jedi Order. However, the crystals were utilized due to their unique properties as healing aids, and were capable of assisting a Jedi healer in easing the pain of a patient and therefore made their treatment easier.[1]
As a result of the Clone Wars, a three-year galactic war between the Galactic Republic and the Confederacy of Independent Systems, thontiin crystals were brought to use on the front lines, and after the lightsaber of a Jedi Knight had suffered a disastrous amount of damage in battle, they sought to replace their damaged crystal they had found on the planet Ilum with a thontiin crystal. After having changed the crystals, the Jedi Knight had discovered that the crystals' healing properties were greatly focused through a carried lightsaber in new ways, which allowed the bearer to battle through debilitating pain.[1]
The healers of the Jedi Order were reluctant to find out that thontiin crystals were being used as weapons, although the desperate circumstances of the Clone Wars had resulted in a handful of its kind being repurposed in a different manner.[1]
Behind the scenes
Thontiin crystals were mentioned in Rise of the Separatists, a roleplaying supplementary sourcebook for the Star Wars Roleplaying series published by Fantasy Flight Games in 2019.[1]
Sources
The Engines of War on Fantasy Flight Games' official website (backup link) (First mentioned)- Rise of the Separatists (Mentioned only)