Heart Scale can be a valuable item that you can use in Pokémon Brilliant Diamond and Brilliant Pearl. With it, you can teach Pokémon old moves that they previously had a chance to learn, but no longer know. These are moves that they naturally learned as they leveled up. But if you want them to remember it, you have to use the heart scale. Here's where you can find the Heart Scale in Pokémon Brilliant Diamond and Shining Pearl.
There are several locations where you can find a heart scale. For us, we managed to find one in the Grand Underground. You will be able to explore this place once you receive the Explorer's Kit from an old man from Eterna, who lives near the town's Pokémon Center. Talk to him at his home, and he'll give it to you, giving you a short tutorial on how to use it.
After using the Explorer Kit a few times, approach the orange icons on the walls of the Grand Underground. These are fossil excavation sites and you will have a chance to find a heart scale by digging at this location. Of course, you won't always get a heart scale, but you stand a good chance of getting one if you were to dig it up from the site.
