Heart Scales are found all over the place; from Underground to inside Pokèballs and even getting them from in-game people. It all depends on what game you have.
underground
You can find them in the Underground
To find heart scales on Pokemon diamond/pearl you need the explorer kit to go underground. once you are underground look for cracks inthe wall, and eventully you will find a heart scale in the cracks.
Heart Scales can be purchased in the Pokeathlon shop for 1000P
They r dug up underground. They are hard to find
You can find the Heart Scale under ground by using the Explorer Kit.
Heart scales can typically be found underground by using the Explorer Kit.
If you dig underground and dig in the walls you can get heart scales.
Heart Scales can sometimes be found on Luvdisc when they are caught.
U can only get heart scales in the pokeballs in the wild. Or you can made a Pokemon hold a heart scale at trade from a different game.
Luvdisc sometimes is carrying them when you catch them, so catch lots.
You cannot find heart scales there. You have to go underground, go digging, and maybe you'll find one.