The "Sword of the Silver Crystal" (also called "The Holy Sword") is a magical sword found by the Sailor Guardians on the moon in Act 10. It was stuck into the ground and Sailor Venus was the only one who could free it. It is from the Silver Millennium and its purpose was to protect Princess Serenity. After Prince Endymion was killed by Queen Beryl, Princess Serenity committed suicide by stabbing herself with the sword out of grief. To avenge their deaths, Sailor Venus took the sword and killed Queen Beryl.
In Act 12, Sailor Venus kills Queen Beryl with the sword once again. After this, strange writing appeared on the sword which only Sailor Venus could read. This happened to be the method to seal away Queen Metalia. However, out of confusion, Sailor Moon killed Tuxedo Mask (whose body was taken over by Queen Metalia) and then killed herself. However, this didn't kill them and only freed Queen Metalia from Tuxedo Mask's body.
In Act 13, in an attempt to seal away Queen Metalia and to try to find Sailor Moon and Tuxedo Mask afterward, the rest of the Sailor Guardians threw away their transformation pens and Sailor Venus called upon the sword once again to give her and the rest of the Sailor Senshi more power. Unfortunately, this plan failed and left them powerless. This was also the last time that the sword is seen in the manga.
Just like the manga, the mystical sword is discovered on the Moon and pulled out by Sailor Venus. The spirit of Queen Serenity appears, who says that is the holy sword that protects the Princess and it could only be used by the four Inner Sailor Senshi.
On Earth in Ami's apartment, Minako used it to shatter the hardest jewel in the world-diamond. In the 12th episode, Sailor Moon used the sword to break the necklace around Queen Beryl's neck, thus severing Queen Metalia's hold over her. The sword was then taken by the evil Tuxedo Mask but later recovered by Sailor Moon. Writing then appeared on its blade:
"When this sword shines bright, when the Silver Crystal hidden inside the one who will someday become Queen begins to shine in the reaction to the wishes of her heart, she will become complete and reawaken the full great powers of the Moon. Offer up a prayer to the holy Crystal Tower, and bring peace to our kingdom once more."
Unable to bear it any longer, Sailor Moon used the sacred sword to stab Tuxedo Mask in the chest and then her own.
Sailor Venus also used the sword in her Venus Wink Chain Sword attack in the 3rd season.
- In the Special Act of the live-action series, Minako used a similar sword called the "Spirit of the Sailor Guardians" with the Sailor Senshi to transform one more time to defeat Queen Mio.
- It had never appeared or used at all in the 90's anime adaptation.
- The sword appears in the Sera Myu musical Pretty Guardian Sailor Moon - La Reconquista. Here, it is Sailor Jupiter who pulls it out of stone.