You have to pass through mount coronet off of the west side of celestic town then you will reach snowpoint city where the 7th gym leader is Required Moves: Strength and Rock Smash
she is never in the gym she is usually in the kitchen tho.
Fly
The first gym in Pokemon diamond is in Oreburgh City
the fifth gym on Pokemon diamond is the one in herthome city,
the fith gym is a sychic gym its in heathrome city
You will find the Pokemon on the rocky island on one of the lakes im not sure which one tho but defete the Pokemon gym leader crash before you lool Hope thi helped
on cinnibar island beat the 7th gym 1st tho
The 6 gym leader in at Canalave City. the gym after the hearthome City gym!!!!!
hearthome gym. you know where that is.
you beat the gym leader
the sixth gym is in canalave city
He is in the lighthouse