Its central core glows with the seven colors of the rainbow. Some people value this core as a gem.
A prototype Pokémon Leagues were given the Trainer Deck B, which included this card, before the Base Set's official release. This print has a red border and "Trainer Deck B" printed on the back. This card was included in the Base Set, first released in the Japanese Expansion Pack. It was reprinted in the Base Set 2 expansion.