I am not a Jedi, so this information may need to be revised by one. To the best of my knowlege, color does not matter. Single crystals are used for making single bladed lightsabres and twin crystals are used for double bladed. Krayt dragon pearls can also be used. From what I've heard, 90% of the time, the pearls make better weapons than crystals. Only a Jedi can tell how good a crystal or pearl is by looking at it. If you buy them you're taking a risk, unless you have a Jedi appraise them for you. Also DO NOT buy Nightsister force crystals. Some people sell them for a lot of cash and tell people that they are used for making sabres, but they are not. I don't know what they re good for.---Gutnug/Bloodfin