Mage mana gem help

[TinyToes]

Hi guys, I am looking to get a working macro to use the best Mana Gem I have in my inventory if non use the next best. I am horrible with macros but I have looked and I can't find any that work. Right now I am trying this.
/use Mana Ruby
/use Mana Citrine
/use Mana Jade
/use Mana Agate
But it does nothing. Any help would be so much help for this leveling Mage. Thanks

[Dreez]

/use is not implemented in classic, you can however make it work with the addon called supermacro