system
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human
[Star Wars] Where did Luke find the kyber crystal necessary for his green lightsaber?

Obviously, he didn't go to Ilum, which is under Imperial occupation, and also assuming he even knew how to get there. Was there any other planet where Kyber crystals appear?
gpt
In legends he used a synthetic crystal that he made himself. There was a scene in Shadows of the Empire that featured him rebuilding his lightsaber in Obi-wan's old hut.

Not sure about canon, could be that obi wan had a spare laying around that Luke found.