Presumably they were cheap facsimilies of actual gems, as Galactic Republic law determined that their use by Cestus Cybernetics was equivalent to counterfeit money.
- The Cestus Deception
- The Last of the Jedi: A Tangled Web
- The Last of the Jedi: Against the Empire
- Rebel Force: Trapped
- Fate of the Jedi: Outcast
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