Originally posted by shangoman
You can make just the crystal but then you have to edit each lightsaber in the game to let the game know what to add to the weapon when your crystal is used. That's what the "UpgradeType" line in the sabers property list is for. You'd also have to edit the "upgrade.2da" file to add your crystal. You may have to edit other files too, not sure as I'm just getting into modding sabers myself. check this post out, maybe the author could give you info:
http://www.lucasforums.com/showthread.php?s=&threadid=129868&highlight)
You don't have to edit Upgradetype.2da, but you do need to add your saber crystals to upgrade.2da. The process is very similar to adding a saber to upcrystals.2da when you're making a lightsaber upgradeable. I'd be happy to make a walkthrough if you're interested.