In Classic & TBC it is possible to make the lower-tier versions of Mana Gems too. Adding an checkbox option for all of them would be great, since if a fight last more than the 2min cooldown, you can use another managem

Macro like this can put all the gems in a single button

#showtooltip
/use Mana Ruby
/use Mana Citrine
/use Mana Jade
/use Mana Agate

I noticed it also doesn't currently understand that when you have a inferior gem in your backpack, it doesn't suggest to make a better one.

Pull request #95 alleviates this