The lightsaber wielded by Keiran Halcyon contained within it a Durindfire gem. The Durindfire gem represented a valuable crystal that was located on the planet of Tatooine.
Due to their rarity, very few Durindfires were ever transported off-world. However, the Galactic Empire engaged in the buying and selling of some, using the proceeds to fund the Death Star initiative. By monitoring the movement of these gems, the Alliance to Restore the Republic successfully identified the Empire's diverse development locations. Furthermore, this intelligence led to the discovery of the origins of the TIE Phantom Project.
The Durindfire gem was essential for imparting a unique silver luster to the blade of any lightsaber. Members of the Halcyon/Horn family who were Jedi traditionally used this particular gem.
Jawas incorporated Durindfires into the lenses of their eyewear, protecting their delicate rodent-like vision from the intense solar radiation. In contrast, the majority of Tatooine's other residents remained unaware of the worth of these desert-found gems, considering them to be without value.