Silver Crystal

The Silver Crystal (幻の銀水晶, Maboroshi no Ginzuishou; often translated as Illusionary Silver Crystal), was a crystal object of great power. The English-dubbed anime sometimes calls it the "Imperium Silver Crystal".

Description
The Silver Crystal possesses tremendous power, and is possibly the single most powerful artifact in the universe. Focusing the energy of the user, it can perform spectacular feats, such as reviving an entire world from ruin, but the strain of using such a power often causes the user to lose their life, as the power actually derives from the life force of the user, a member of the Moon dynasty.

Originally, the Silver Crystal belonged to Queen Serenity of the Moon Kingdom; whilst using the crystal to protect the Moon and the Earth, it also allowed the people of the moon to enjoy long lives. When the Moon Kingdom was destroyed by Queen Beryl under the influence of Queen Metalia and the Queen's daughter, Princess Serenity was killed along with her guardians and Prince Endymion, Queen Serenity used the Silver Crystal to seal away the enemy, as well as to send her daughter, the prince and all of the Sailor Scouts to be reborn in the future on Earth, so they could hopefully live happy, peaceful lives. Having used too much of the crystal's power, the Queen then died.

Manga
The Silver Crystal was the object of desire of the Dark Kingdom and Tuxedo Mask; the former wanted it for power, the latter to restore his memories. It first appears in Act 9, when Tuxedo Mask protected Sailor Moon from Kunzite; her grief caused her to remember that she was Princess Serenity, and he remembered he was Prince Endymion. When Tuxedo Mask then died in her arms, the pain was too much, especially when she recalled their former lives; a tear fell from her cheek and glowed immensely bright, forming the Silver Crystal. Its light healed all of those it touched, and a part of it went inside of Tuxedo Mask's body, which was then stolen by Kunzite. Serena kept the Silver Crystal on a necklace around her neck for a while before it was stored inside her second transformation compact, the Crystal Star.

It was revealed that it served as Sailor Moon's Sailor Crystal, evolving into what is known as the Silver Moon Crystal.The crystal is usually used to defeat the final villain of each story arc. It had two primary powers; the ability to generate a powerful, magical attack, and the power to rejuvenate. Additionally, it seems that the Silver Crystal has both more control and focused power when attached to the Moon Stick (Crescent Moon Wand), though, eventually, Serena becomes so in-tune with its power, she no longer needs the Moon Stick.

In act 10, when they visit the ruined Moon Castle, Queen Serenity told Sailor Moon that the Silver Crystal's true power depended on her heart. Later after defeating Queen Beryl in Volume 3, Sailor Venus reads from the sword that the true power of the Silver Crystal was of from Serena's heart and the Moon.

Anime
In the anime storyline, following the destruction of the Moon Kingdom, the Silver Crystal was split into the seven Rainbow Crystals so as to seal away the Seven Great Youma. It first appeared in episode 34 "The Sparkling Silver Crystal! The Moon Princess Appears" (episode 30, "A Crystal Clear Destiny" of the English dub). Tuxedo Mask protected Sailor Moon from Zoicite's attack and was mortally wounded, causing Sailor Moon to cry; her tears made the Rainbow Crystals react, forming the Silver Crystal and revealing Sailor Moon to be Princess Serenity. The crystal attached itself to the Moon Stick, and enabled Princess Serenity, and later Sailor Moon, fend of Kunzite's attacks. Following the defeat of the Dark Kingdom, and Serena's return to being Sailor Moon, the Silver Crystal is placed into her Crystal Star compact, and then, seemingly, her other transformation compacts as they evolve throughout the series. In the future, it healed the Earth of an unknown ecological disaster and created Crystal Tokyo.

The anime embellishes on the crystal's power. In the final battle of the first series and in the Sailor Moon R movie, it was shown to be able to construct a shield. Also, after initially attaching to the Moon Stick, it served to heal people back to their true forms, although it failed to heal Prince Endymion from Metalia's influence before the final battle. The Silver Crystal is also able to borrow the powers of the other Scouts to further amplify its own powers, such as in the last episode of the first season. It is also used far more in the anime than the manga, and appears to take on a number of shapes; round, lotus and pyramid.

Another Silver Crystal
As the daughter of Neo-Queen Serenity, Sailor Mini Moon possesses a future version of the Silver Crystal, which is her own Sailor Crystal. In the anime, it resides in her transformation compact. When it evolves, it is known as the Pink Moon Crystal, and allows Sailor Mini Moon to transform into her "eternal form".

Trivia

 * In Sailor Moon Sailor Stars, it is revealed that the Silver Crystal is Sailor Moon's Star Seed.
 * In the English dub, the crystal was called different names by many people such as the Silver Moon Crystal, the Silver Crystal, Imperium Silver Cystal, and Imperium Crystal.