Sapith
From Wookieepedia, the Star Wars wiki.
Sapith was a type of crystal occasionally used in lightsaber construction. The crystal was excreted by the now extinct Volice worm, a creature from the Ssi-ruuk homeworld Lwhekk, once every eleven standard years.
When set in a lightsaber's crystal chamber, sapith generated an intense blade, easier to control than most other blades.
