Malefic Black Crystal

Not to be confused with the Black Crystal.

The Evil Black Crystal, or Jakokusuishou (邪黒水晶), was a large and jagged crystal from Sailor Moon R which grew with negative, dark energy. It was a crystal from the planet Nemesis that Death Phantom used to try and destroy the 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.

In the anime, after the great battle in episode 88, Usagi and Chibiusa used the power of their two Silver Crystals to destroy the Evil Black Crystal.

In the English dub, this material was called "the Dark Crystal," in the TokyoPop/Mixx manga translations it was called "the Black Poison Crystal," and in the Kodansha manga and in Sailor Moon Crystal it is called "the Malefic Black Crystal."