Since I noticed that we actually have other mages that raid, crazy right, I thought I might post my Mana Gems Macro! It's awesome.

[code:1:6101277dc6]/castsequence &#91;nocombat&#93; reset=120 Conjure Mana Emerald, Conjure Mana Ruby, Conjure Mana Citrine, Conjure Mana Jade, Conjure Mana Agate;
/stopmacro &#91;nocombat&#93;
/use Mana Emerald
/use Mana Ruby
/use Mana Citrine
/use Mana Jade
/use Mana Agate [/code:1:6101277dc6]

That's the macro, it works, wonderfully. 

If you click on it when you're out of combat, you'll conjure the next available mana gem in the list. If you're in combat, you'll use the next available mana gem in the list. It does cause some errors to be displayed, though, such as if you die and want to continue making gems.