technically there is one it is unown it looks like the alphabet.
Seven island.
After you defeat the Elite Four.
Beat the Elite Four, Get Rainbowpass from cello,and tada! You are at seven island
you have to have the rainbow pass. you take the ferry
The gem is on six island not seven island and its inside a cave called dotted hole.
No legendary resides on the islands a rare Pokemon resides on seven island in the tanoby chambers the Pokemon is unown.
In Sevault Canyon on Seven Island.
you have to beat the trainers and the time in that place on seven island
On cinnabar island but you need to get the secret key in Pokemon mansion first.
You have to catch a larvitar at Sevault Canyon on Island Seven and evolve it.
Larvitar can be found on Seven Island at Sevault Canyon (southern part of the island).
You have to fight the Pokemon league to unlock island four, five, six, and seven.