From Bulbapedia, the community-driven Pokémon encyclopedia.
A pearl figure is a special type of figure from the Pokémon Trading Figure Game. It is identical to a normal figure except that it is made out of a shiny, white material, similar in appearance to pearl and the base is not transparent at all. The rare figures are the only ones which have pearl variations of them.
They can be compared to holographic cards in the Pokémon Trading Card Game. However, unlike holographic cards, they are not numbered as separate figures from their normal counterparts.
List of pearl figures