Bronze Ioun Stone

Bronze Ioun Stone gives the wearer an extra lvl 7 spellslot. It can only be equipped by bards, mages and sorcerers. The stone weighs 2 lbs. The stone can also be used to upgrade the Circlet of Netheril. This item appears in Baldur's Gate II: Throne of Bhaal and this item will probably appear in Baldur's Gate II: Enhanced Edition. It's not known where this item can be gained.

In-game description
"The powerful enchantments on this ioun stone make it a treasure eagerly sought after by wizards and mages."