Luxum
this was one of the many crystals used by the ancient Sith Lords in the construction of a lightsaber. It was believed to have given the wielder the ability to damage a droid opponent. Luxum crystals were formed from the minerals that were found in the waters of Lake Natth, on the planet Ambria. It took long hours of meditation to create one of these crystals, which were used almost exclusively by the Dark Jedi of the Great Sith War.