"... Ah. Apologies. Yes. Lightsabers are made out of several components, but possibly the most important, and certainly the one with the most personal symbolism and significance, is the crystal. It is precisely that- a rare crystalline gemstone, resonant with and attuned to the force, through which the light that creates the beam is focused. Obviously, any laser must be focused through a lens of some sort, but this also creates a personal attunement with the lightsaber, more effectively bonding it to you. It is agreed by most Jedi that the lightsaber and the robes are our only true possessions, and that even the latter can be changed or disposed of if need be."