Blue Field Passage Gem

The blue field passage gem is an artifact which allows its bearer to pass through the magical barriers en route to the Hall of the Mountain King unscathed. It appears in  Ultima VIII.

Description
The inner sanctum of Lithos was defended by a number of magical traps and barriers, including an elaborate maze consisting of blue force fields. Should the Avatar retrieve this gem, they could pass through these fields unharmed, making passage through the labyrinth an easy task.