Saw it. Great movie.
*nerd glasses on*
I thought Jedi used natural kyber crystals because part of the initiation trials of becoming a Jedi was constructing their first light saber and obtaining the crystals necessary to build one. Natural kyber crystals have the blue and green glow.
Sith initiation trials were different. They killed their master. The symbolism of obtaining natural kyber crystals was meaningless so they used synthetic crystals. The synthetic crystals glow red.
Possible spoiler alerts for Rogue One, read at your own risk. I tried to remain vague when referencing the film.
The problem then becomes the color of the laser. Kyber Crystals were clear until harvested by a Jedi or Sith for use in constructing a lightsaber. Jedi harvested crystals would typically turn blue or green during this process unless your name is Samuel L. Jackson. Due to their corrupted intent the Sith would have to dominate and warp the Kyber crystals causing them to turn red typically.
*nerd glasses on*
I thought Jedi used natural kyber crystals because part of the initiation trials of becoming a Jedi was constructing their first light saber and obtaining the crystals necessary to build one. Natural kyber crystals have the blue and green glow.
Sith initiation trials were different. They killed their master. The symbolism of obtaining natural kyber crystals was meaningless so they used synthetic crystals. The synthetic crystals glow red.