Whats a heartscale?

[puffle4life]

I wanted to know whats a heartscale. i found 3 underground at once. i think their rare but i dont know what they do. someone tell me.:|:|:|

[digitalree]

you use them to change your pokemon's moves in pastoria town.
But you need the move deleter to delete the move

[Chaolin]

They are a token for the move tutor who in returns, "tutors" your pokemon to learn a new move. He is in Pastoria City.