A ring bearing a magickal jewel.
In the original version, Sage's Ring is an accessory that absorbs Holy-elemental damage and halves MP costs. It requires the Accessories 19 license to equip. It can be bought for 22,000 gil at Old Archades, found as treasure at Henne Mines (Special Charter Shaft) and Great Crystal (Sirhru Jilaam Pratii'vaa), stolen from Arioch (3% chance), and from doing the Hunt Club sidequest.
In the Zodiac versions, Sage's Ring now requires the Accessories 14 license to equip and can be found as treasure at Henne Mines (Phase 2 Shaft), Stilshrine of Miriam (Ward of Steel), Pharos - Subterra (Umbra - South), and Trial Mode Stage 80 & Stage 94 (with the Diamond Armlet equipped), stolen from Arioch in the main game and Chaos in Trial Mode Stage 84 (3% chance) and Evil Spirit in Stage 88, and from doing the Hunt Club sidequest.
Sage's Ring is an accessory exclusive to the War of the Lions remake. It is the most powerful ring, boosting the power of the user's elemental attacks as well as absorbing all elemental damage. It can be obtained from the Rendezvous mode.