Kathracite
this form of Adegan crystal was the most plentiful, but it was discovered to be much weaker in form than the mephite crystal, making it almost unsuitable for use in the construction of a combat-ready lightsaber. Kathracite could be used in an emergency, but there was a considerable risk of an explosion due to power overload. Kathracite did have its uses, however, especially in low-powered training lightsabers.