Well I think it's good to have a guide,where the abilities from enchanted are listed.
I order to enchant,you have to click icon on the gem on your inventory screen
and then chose the equipment,which you want to enchant (you need either a Ruby or an Emerald

).
Then click either on the emerald or the ruby to enchant it.
Now some abilities you might get:

Effect: Mdef +4

Effect: Atk +20

Effect: 4% more added to your burst(limit) bar per hit done or taken

Effect: 2% chance to deal a critical hit,which inflicts 1.5 damage(Something like that

)

Effect: 3% added movement speed (stacks up til 20%)

Effect: HP+ 2% (Maximum +50% ?)

Effect: 2% accurate attack (stacks up til 20%)

Effect: 1% chance to evade (stacks up til 20%)

Effect: Matk +30

Effect: Increases burst mode duration (?)

Effect: currently unknown
Thanks to Hector for the translations