Maybe the devs are already working on a crystallography skill tree, but I would love to see different types of crystals.
Maybe with crystallography + intermediate admixing you can create crystals with different powers.
There could be crystals to "trap" things in. You could make an energy crystal to trap a certain number of energy points. Those points are deducted from your energy bar when you create it, but then you can release them whenever you want. Same thing with mood.
What other powers can you come up with that could work with crystals?