experimented a little with lvl5 rb gem
and i got a results like this

HP MAtk
HP PAtk
MAtk Armor
PAtk Armor+
HP MAtk PAtk Armor

HP MAtk
HP PAtk
MAtk Res
PAtk Armor+
HP MAtk PAtk

HP MAtk
HP PAtk
HP Res
HP Armor+
HP & Random (MAtk/PAtk/Res/Armor)

HP
MAtk
PAtk
Armor+
HP MAtk PAtk Armor

MAtk
PAtk
Res
Armor+
MAtk PAtk Res Armor