Crystal As it digs through the ground, it absorbs many hard objects This is what makes its body so solid Ruby Sapphire ONIX has a magnet in its brain It acts as a compass so that this POKéMON does not lose direction while it is tunneling As it grows older, its body becomes increasingly rounder and smoother FireRed It usually lives underground Top Voted Answer To evolve Onix into Steelix, you need to trade it while it's holding a Metal Coat After the trade, it'll evolve, and you'll just need to trade it back User Info th3l3fty th3l3fty 12 years ago 6 0The Crystal Onix appeared in one of the anime episodes This is just a theory, but it would be awesome! Crystal Onix And Crystal Steelix Custom Variants Pokemonromhacks Onyx crystal pokemon