Kathracite crystal

Kathracite cystals were a type of crystal that could be used in the construction of lightsabers. Most training lightsabers used by the Jedi Order to train their younglings contained either a kathracite or danite crytsal. These lightsabers were non-lethal and low powered.

Behind the scenes
Kathracite crystals were first mentioned in the new Star Wars canon in Rise of the Separatists, a 2019 supplement to Fantasy Flight Games' series of Star Wars roleplaying products.