[quote=@Revans Exile]
Can you point to a specific instance from one of the six movies, Clone Wars, The Clone Wars, or Rebels where a crystal provided a benefit or a shortcoming?

Gameplay mechanics are not a valid reason.

[/quote]

If you're being a holdout for Disney's new canon, then no, I don't think so. That said, there were at least a couple crystals in the the old canon (actually in the comic books) that supposedly had powers. By name, all I can offer you is the Kaiburr crystal (Luke mentioned them when he was talking about lightsaber creation), though I'm sure a quick trip to the Star Wars wiki would give you a few more.

I'm thinking of making a character. Not 100% sure, but I thought I'd chime in with that and this. They'll more than likely be a separatist, given the amount of Republic characters. Maybe a gray Jedi or a bounty hunter.