Sealing Crystal

Sealing Crystal is a magic item that can seal high level spells.

Description
In the New World, sealing crystals are look upon as legendary items imbued with great power. The legends and tales revolving around these items originate from the Slane Theocracy. According to Nigun the crystal was a very rare treasure very few people in the Slane Theocracy possessed. This item was one the national treasures of the Slane Theocracy's left behind six-hundred years ago by the Six Great Gods until its current holder Nigun Grid Luin used it in a failed attempt to defeat Ainz Ooal Gown by summoning a high rank angel.

Appearance
Sealing crystals seem to come in a variety of shapes and hold a quality of brilliance depending on what types of magic they contain.

Abilities
Sealing crystals are incredibly powerful artifacts in the New World, as they are capable of containing seven tier or higher magic, an impossible feat for humans who are unable to contain or cast such magic. Thus, sealing crystals are considered extremely valuable to any nation that possesses one. The magic released by a sealing crystal can only be used once, so holders of these items would only use them as a last resort.

Afterwards, one must go to great expense and perform extensive rituals to recharge the spell within the crystal.

Trivia

 * Magic Casters ,on the New World, highly prize these sealing crystals as they are a subject of much debate and study.
 * In the official manga, the Sealing Crystal was shattered into pieces when the summon it held was released from confinement.
 * Ainz determined from the brilliance that the crystal Nigun used is unable to hold magic over the 10th tier, Super-Tier Magic.