Evil Black Crystal
The Evil Black Crystal, or Jakokusuishou (邪黒水晶), was a crystal from the planet Nemesis that Death Phantom used to try and destroy the Earth. Most members of the Black Moon Clan, with the exception of Saphir, wore earrings made of this crystal, and could use the power of their earrings to attack.
In the manga, the musical Tanjou! Ankoku no Princess Black Lady and its revision, and Sailor Moon Crystal, Petz used her earrings made of Evil Black Crystal to create a tornado attack against Sailor Jupiter; this attack proved to be more powerful than Sparkling Wide Pressure. In both musicals, Esmeraude and the Spectre Sisters used the power of their earrings in their attack Black Vicious Crystal, and Esmeraude alone used it when she performed Vicious Emerald.