he shape symbol on a genuine Pokemon card tells you how rare or common the card is and is also indicative of its trading value. The rarity of the Pokemon card can be determined according to the symbol. Black Circle signifies common rarity, Black Diamond signifies uncommon rarity, Black Star signifies rare rarity, and Black Star with the word "PROMO" signifies promo rarity (given out only on related special events such as a movie or game releases).