Wild horsea sometimes have it.
defeat red gyarados.
You can go under ground
its inside pastroia city.
You have to battle a legendary Dragon-Pokemon in Pearl. You will have the greatest chance by facing Giritina, Diagla, Palkia, Darghina, Charizard, or Ghalstone. (Darghina, Charizard, and Ghalstone are not legendary Dragon-Pokemon, but they will supply you with a dragon scale).
The Prism Scale cannot be obtained in Pokemon Omega Ruby and Alpha Sapphire. You'll need to trade for a Pokemon holding the Prism Scale to get it.
you use it on move tutors to teach your Pokemon moves
Because it has to be on Pokemon Diamond,pearl or Plainum.
You can get Heart Scales in Pearl from digging in the Underground and (P.S. This is for after you get the National Dex) from wild Luvdisc.
you can get a dragon scale by catching a wild seadra , dratini or dragonair and hope it's holding one.
It depends on how rare the Pokemon is. On a scale of 1 to 10of rareness, the higher it is in the scale, the longer it will take.
After you get the HM Rock Climb, and a Pokemon knows it, you can approach a rocky wall, press A, and you will scale the wall.