Conjure Mana Gem

Conjure Mana Gem is a mage spell which conjures a mana stone that stores mana for later use. Mana stones are soulbound, and cannot be traded to other players. They are unique, meaning that a mage can only carry a single stone at a time regardless of rank. When used, the stone instantly restores mana, similar to a mana potion with its own 2 minute cooldown. Mana stones are not considered conjured items and do not disappear after logging off for 15 minutes. The versions with more than one charge regenerate charges while you are not logged in. (Lower level ones are, of course, consumed on use.)

Tips and tactics
Don't wait until you're out of mana to use a stone. In a fight that will be more than two minutes long, use your first charge early in the fight, after you have used enough mana to use the stone and not over-restore mana. A second charge will be available before the end of the fight.

Since all potions share a cooldown timer, you can use this instead of a mana potion that would put the health (and mana) potion on the cooldown timer. If you always uses your mana stone before your mana potion, you have quicker access to your health potion.

Two pieces of Frostfire Garb increases the mana gain by 40% and grants you +225 spellpower for 15 seconds after using the mana gem.