Freedon Nadd's crystal

The crystal of Freedon Nadd was a blue lightsaber crystal, powered by the Krath Lord when he was a Jedi.

The crystal itself was made to focus the Light power in the user, and to fight the Dark Side that would surround its bearer. Freedon Nadd created such crystal to protect himself from the Dark Side... However, Nadd ended up falling to the Dark Side as well, and since the crystal was against him, the Krath Lord was forced to let go of his powerful creation.

The crystal was lost in the Krath's tomb for a long time. The Jedi Master Orius Malfar found it in his first mission on the planet, and brought it with him to the Jedi Temple, in Coruscant. There, the Jedi Master crafted a lightsaber for his padawan, Hei-Ri Devon.

Devon used the crystal to defeat Darth Revan, in the Duel of Fates between the Jedi Knight and the Dark Lord.