Shield of Crystal is a shield spell which can be put on your out of combat utility bar, but Elysian Illumination can't even though it's a shield spell also. Would like to see Elysian Illumination be able to be applied out of combat on your utility bar prior to a fight.
Shield spells should always be charged. It increases their power and duration. You cant charge them from the utility bar, so it's not an effective place to put them anyways.
New Suggestion: There should be text saying that this mechanic exists on the tooltip of the spell. I didn't know you could charge spells. This is news to me.
I know it's not clear but the number you can charge it to is listed on the tooltip. At skill level 20, you can charge it to 2; skill level 40, 3; skill level 80, 4 and skill level 100, 5. If you have specialization at or above 80 then you get one more charge level for all the glyphs in that tree.