The Taioron Crystal (タイオロン・クリスタル) was an item that appeared only in the manga as well as the musical Mugen Gakuen - Mistress Labyrinth and its revision. It was a crystal used as a power source by the Death Busters and as a pain reliever by Hotaru Tomoe. It was said to be full of energy from the Tau Star System, the Death Busters' home dimension.
The Taioron Crystal was once a powerful item but it started to lose its energy, weakening Pharaoh 90 in the process. The Death Busters wished to make the Crystal strong again in order to take over the world and make it their new home planet. To achieve this, they planned to feed Pharaoh 90 with the energy of human souls. When Mistress 9 stole Sailor Chibi Moon's Silver Crystal for energy, Pharaoh 90 crushed the remnants of the consumed Taioron Crystal and took the power of the Silver Crystal as its replacement.
Amulets made from the Taioron Crystal were used by Magus Kaolinite to perform her most powerful spells, and in Act 31 of the manga she gave one to Cyprine so she could accomplish the mission of killing the Sailor Senshi. Hotaru's own Taioron Crystal amulet was given to her by her father, who claimed it was originally worn by her mother.