Apricorns were introduced in the original Gold & Silver. These nuts were found on trees all around Johto, these can be used to ma e special PokéBalls. However, in addition to that, Pokémon Heart Gold & Soul Silver has added new functions for the apricorns.

In Heart Gold & Soul Silver, the Apricorns are stored within a special item called the Apricorn Case. This can hold many of each Apricorn. You can't grow the Apricorns in this game, but the trees which hold them are quite common and you can pick an Apricorn from it every day so be sure to remember where they are so you can get the balls.

PokéBall Creation

Each type of Apricorn can make a certain kind of PokéBall. If you take these Apricorns to Kurt in Azalea Town, he will make the PokéBalls for you with no fee. It takes a day for him to make the PokéBall and he only makes one at a time. Below is a list of the PokéBalls he can create, what they do and what Apricorn is used to make them.

Icon	Name	Apricorn Used	Effect	Fig.
	Fast Ball	White Apricorn	A Ball that catches Fast Pokémon If the Pokémon does not have a high Speed then * 1. Else * 4	* 1 * 4
	Friend Ball	Green Apricorn	A Ball that makes Pokémon like you The Pokémon's Base Happiness is 200 instead of 70	* 1
	Heavy Ball	Black Apricorn	A Ball that catches Heavier Pokémon Easier If the Pokémon is Less than 220lbs then -20, Between 220lbs & 440lbs then +0, Between 440lbs & 660lbs then +20, Higher than 660lbs + 30	-20, +0, +20, +30
	Level Ball	Red Apricorn	The bigger the difference in level between your Pokémon and the Capture Target, the more likely the capture If the Pokémon's Level is greater than the opponent's level then * 2. If half your Pokémon's Level is greater than the opponent's Level then * 4. If a quarter of your Pokémon's Level is greater than the opponents Level then * 8	* 2, * 4, * 8
	Love Ball	Pink Apricorn	This ball works better on Pokémon of the opposite Gender If the Pokémon's Gender is not the same as the Opponent then * 8. If it is the same or either have no gender then * 1	* 1 * 8
	Lure Ball	Blue Apricorn	This ball works better on Pokémon snagged with Fishing Rod If the Pokémon was obtained through Fishing then * 3. If the Pokémon wasn't, then *1	* 1 * 3
	Moon Ball	Yellow Apricorn	This ball works better on Pokémon that evolve with Moon Stone If the Pokémon evolves with Moon Stone then * 3. If the Pokémon doesn't, then *1	* 1 * 4

The new feature of the Apricorns is that you can now use them with a special item called the ApriShaker that can crush the Apricorns down and turn them into the ApriShakes. The ApriShakes work in a similar manner to Poffin and PokéBlocks. Each kind of ApriShake can raise your Pokémon's Pokéthlon statistics

Information obtained fron Serebii.net