U cant, why would they let join the evil people who tried to control legendary for no good reason! unless u hacked it and i dont know how to do that, but anyway no u cant join team magma! This is from GREGELOCITY
You must go to the Cable car above mauville citty, then when you are arrived go down to lavarigde town on That road
you have to win beauty contest in every city and finish the elite 4 and then buy 50 pokeballs in first city
i am not quite sure i think
you go threw the cable cars then it should shake then a cave will open
You do not need and you cannot get the Magma Emblem in Pokemon Ruby. The Magma Emblem is a story item exclusive to Pokemon Emerald.
run for your life you cant find it
If you have the Magma emblem go to jagged pass and somewhere along there is the door. Just stand in front of it and it will recognize the emblem and open.
The Magma Emblem is used for getting into Team Magma's base in Pokemon Emerald Version.
YOU TRADE IT WITH MAXIE THE TEAM MAGMA LEADER
To infiltrate the Magma Hideout in Ruby Version, go to Mt. Pyre. At the top, the old woman should give you the Magma Emblem. Then go to Jagged Pass and wander around. when you get to the right place, the Jagged Pass will react with the Magma Emblem. Then the entrance to the Magma Hideout appears. Warning: you have to fight Magma Leader Maxie. Hope this helped! Shinin.
go to magma hide out
From The lady inMT.PYRE
somewhere in their base
go to mount pryre.
um...there is no Pokemon named magma...
CHIMECHEO CAN BE FOUND NEAR YOU GET THE MAGMA EMBLEM.