Azura's Star (Oblivion)

Azura's Star is a powerful soul gem, unique in that unlike all other soul gems it is reusable. Soul gems are used to enchant or recharge powerful items. Azura's Star can also hold powerful souls like Almalexia and Vivec, while the most powerful conventional gem, Grand Soul Gem, can not. It appears in The Elder Scrolls III: Morrowind