Soul gem

A soul gem, also known as a spirit gem was a specific gem that was used to magically contain the spirit or soul of another living being.

Description
Often sculpted in the shape of eggs, these gems shone with a strong radiance that could illuminate darkened spaces. When they released energy stored within, their radiance intensified to the point that it would daze every onlooker within the room it was located.

Soul gems were often incorporated into the physical form of undead—such as liches, demiliches, or dracoliches—whenever they were used to preserve the undead's soul. On some occasions, they were included as part of a magical item, or attached unto furnishings or decor; other times, they remained suspended in midair, floating above ground.

In some instances, soul gems were encased within a protective force sphere that had to be destroyed before the gem itself could be accessed.

Powers
It was possible for the spirits of the dead to use a soul gem to communicate with people on the Prime Material plane, even if their soul had no connection to the gem.

When utilized by undead beings, soul gems acted similarly to phylacteries; the gem's destruction would allow the physical form the undead to be permanently destroyed.

Uses
In addition to their intended use, soul gems could be used to create deadly traps utilizing radiant energy. In some instances, these traps actually siphoned the soul from its victim, leaving the dead husk of their body behind.

Notable Spirit Gems

 * The topaz embedded into the staff of Lady Lord Yanseldara held the spirit of the dracolich Hethcypressarvil, and for a brief time, her own.
 * The sword of High Blade Selfaril Uoumdolphin was inlaid with a soul gem that held the soul of his twin brother Rassendyll.
 * The white dragon matriarch Icasaracht kept a soul gem within her lair in Wyrm Wyrm iceberg in the Sea of Moving Ice.
 * Drawing the void card from the deck of several things trapped the users soul within a soul gem in an unnamed temple of Moloch.

Appearances

 * Novels
 * The Veiled Dragon
 * Video Games
 * Icewind Dale: Heart of Winter • Baldur's Gate II: Throne of Bhaal
 * Organized Play & Licensed Adventures
 * Elemental Evil (The Sword of Selfaril)