From Istaria Lexica
Jewelry raises significant the character stats. Besides the decorative aspect the jewelry is as important as armor. Jewelry is crafted by a Jeweler using the Jewelcraft skill. The jewelry may have techniques applied to further improve the boost gain. A complete set consists of two earrings, two rings, two bracelets and one necklace. For adventure tasks usually the health jewelry or the broken jewelry is used. For crafting purposes use the jewelry that boosts the appropriate skill, check the Attribute Skill Chart.
Jewelry can be used by: Battle Mage, Berserker, Blood Mage, Chaos Warrior, Cleric, Conjurer, Crossbowman, Druid, Elemental Archer, Flame Disciple, Guardian, Healer, Ice Disciple, Knight of Creation, Mage, Monk, Paladin, Ranger, Reaver, Scout, Shaman, Sorcerer, Spiritist, Spearman, Spirit Disciple, Storm Disciple, Warrior, Wizard, Alchemist, Armorer, Blacksmith, Carpenter, Confectioner, Enchanter, Fitter, Fletcher, Gatherer, Jeweler, Mason, Miner, Outfitter, Scholar, Spellcrafter, Tailor, Tinkerer, Weaponsmith, Weaver
Jewelry set items
Jewelry set items are rings, earrings and necklaces that once dropped as ultra rare loot from Tier 6 monsters and are no longer generally available in Istaria. They are made for specific classes and the more pieces you wear, the better the buff gets. There are eight different jewelry sets. Once equipped the items cannot be traded anymore.