Crystal Onix is a special Pokemon. It can be found in Route 14 and when it is catched it's name is Onix. It is rarer than Legendaries according to assessment results and is also the rarest Pokemon in the game.
Warning: Make sure to save right after you catch it as it is not a one time encounter but because of its rarity, we recommend you to save after you catch it unless you don't want it.
Rarity: 1/1600 (0.0625%)