You have to beat the gym leader, Pryce, in Mahogany City.
GET THE LAST BADGE......
the seventh gym badge snowpoint gym
when you get your seventh badge and you will head for mount cornet
pryce the ice type gym leader
I'm pretty sure it should be the last badge before you go off to the elite 4:)
GET THE LAST BADGE......
With the seventh badge in Pokemon Ruby version, you can control caught or traded Pokemon up to level 70.
You go to get your 7th Badge in Mossdeep City.
the seventh gym badge snowpoint gym
In Pokémon Liquid Crystal, to challenge the seventh Gym Leader, you must first defeat the previous six Gym Leaders in the Johto region. After obtaining the Zephyr Badge, Hive Badge, Plain Badge, Fog Badge, Storm Badge, and Mineral Badge, you can access the Mahogany Town Gym, where the seventh Gym Leader, Pryce, awaits. Make sure to have a well-rounded team to counter his Ice-type Pokémon effectively. Once you defeat Pryce, you'll earn the Glacier Badge.
when you get your seventh badge and you will head for mount cornet
It's located inside Pokemon mansion which can be found near the seventh gym.
In gym number seven
any level up to 100
In the mahogany gym
Trade a Pokemon from an old version and make sure you have the fifth badge.
in mohogany town where the seventh gym is at