The Evil Black Crystal, or Jakokusuishou (in Japanese: 邪黒水晶), was a diamond-ahaped black crystal from Sailor Moon R which grew with dark, negative energy. It was a precious mineral from the planet Nemesis that Death Phantom (Wiseman) used to try and destroy the planet Earth. The Black Moon Clan intends to let it grow enough to open the Black Gate and allow the world to be destroyed. The leaders of the Black Moon Clan, with the exception of Saphir, wore earrings made of this crystal.