No diamond smacky smacks.
Oddball element with Emma's design is that she scales off two different sets of attributes when she switches forms, which makes gearing her an absolute pain in the ass and may foxhole you into one side of talents or the other.
On the one side, her diamond form scales off durability and strength, and gets damage bonuses for defense. Her defense scales off, well, defense and deflect in her diamond state. So that's STR/DUR/DEF/DEFL.
Her normal form scales off durability and intelligence, and her defensive traits scale off dodge and deflect, with no bonuses to defense, and several of her abilities then scale off of attack speed bonuses (her channels).
That paints a fucked up picture of stat allocation insanity and makes hybrid builds very difficult to work with. Her diamond form is tank oriented. Her mental form is dps oriented. Both can still do damage, but her diamond form deals much less damage than her mental form.
If you want to hybrid, well you'd have to balance between ranged+mental, or physical+melee. Then you'd have to go down the middle with durability + deflect, which are shared by both of her forms. Some of her unique gear will have stats for one side, and some has stats for the other side, so up to you which you go with.
In this case I just went with all mental as diamond form really doesn't have a lot of moves that deal with AOE, which makes it that much more obtuse when trying to handle the cosmic trial. Her summon minions also underperform enough that you'll be dropping hard dps potential if you spec into either the minion or the living nightmare apparition. Doable with enough bolstering and infinity points, but still a massive drop in dps potential either way. Not a very well balanced kit, overall, with one side being clearly the dps side and the other the tank side, so for the most part, going to have a much easier time with the shooty pew pew dps by going the mental route. (TAKE YOUR MEDS)