Onyx is a base pokemon. But, it can evolve into Steelix which can be done by giving it the METAL COAT to hold, and then trading it. Alternatively, you can catch its evolved form, Steelix, in Cliff Cave between Cian Wood City and the Safari Zone.
It evolves into steelix at level 50.
The first answer is wrong. Onix only evolves when a metal coat is given to it and its traded over to a friend who has either gold version or silver version.
Onyx doesn't evolve by level you trade it holding a steal coat!!!!! ONYX ONYX ONYX
Pokemon Opal and Pokemon Onyx are not yet real Pokemon games.
Be level 20 and go to tournament and it might be in there.
A green onyx (if you are talking about pokemon) is a shiny and rare pokemon. tough I have never seen one
Geodude and Onyx
Onyx
rock tunnel
level 100
level 101
That is impossible, Pokemon only go upto Level 100.
Level 934, that's the highest they go.
You get a rock pokemon. Like Onyx.