Ethereal Ring

The Ethereal Ring is a magical artifact which features in  Ultima VII. With it, the Avatar is able to penetrate the defenses of the Tetrahedron Generator in the dungeon Deceit.

Description
The Ethereal Ring originally belonged to the Gargish king, Lord Draxinusom, who was forced in the years after his people's immigration to Britannia to sell it to the mad "Sultan" of Spektran, Martingo. Years later, when the Avatar at last awakened the sleeping sorceress Penumbra in Moonglow, the seer told the hero that they would have need of this ring in order to best the perils of the Guardian's generator, that they might restore the ravaged ether.

Landing on Spektran, the hero reclaimed the ring from Martingo, who had locked the item in his specially guarded safe, which stood defended by a Stone Harpy. Returning to Penumbra, the Avatar had the woman enchant the ring for them, that they might enter the blackrock Tetrahedron and extinguish its power.

Trivia

 * In the SNES Port of Ultima VII, Draxinusom purposefully hid the Ethereal Ring in the Dungeon of Unknown Fears on Spektran. In this version of the game, the Ethereal Ring cause the Avatar and their weapon to align with the ethereal plane, thereby allowing them to combat the generator's guardian.