This used to be the rarest jewel in Mu until the Chaos Castle event started
Jewel of Life - This jewel increases an item's option by 1 level. It is the only way to make an item have a +16 (global) or +28 (private servers) option or a shield has a +20 (global) or +35 (private servers) option. It has a 50% aion online gold chance of success, regardless of luck, and if it fails, your item will lose its option.
Jewel of Creation - Combining a Jewel of Creation with a Jewel of Chaos may create a fruit. This fruit, when eaten, will either boost or decrease one of your stats by 1-3 points. This used to be the rarest jewel in Mu until the Chaos Castle event started, where it's a common winning prize.
Jewel of Guardian - The Jewel of Guardian is used during the Castle Siege to create life stones and for the Lord's Mix.
Hacking Cost: 9 Mana - Most commonly found on Axes (may be referred as the Falling Slash skill). The user of this skill jumps, and then hit the target from the air. It can be used to hit far enemies (up to 2 squares away); this skill will often shake the target and will move it.