Apricorns (ぼんぐりのみ, Bonguri Fruit) are nuts that grow on trees in the Johto region. They are picked like Berries, but used to create new Poké Balls. Kurt, a Poké Ball smith who lives in Azalea Town, can make each Apricorn into a different kinds of Poké Ball which is unavailable elsewhere in the Pokémon world. These Apricorn Balls are rarer than other kinds of Poké Ball, in older times, most all Poké Balls were made from Apricorns rather than manufactured as they are in current times.
List of Apricorns
They come in different colors that determine what Poké Ball is made: