I used Pixel FX Designer to make this:
My goal is to re-create the FF3 (US Edition) Ultima spell.
I'm ignoring the hue-change and sinusoidal-effect to the background. I think the half-orb is super-cool, so that's my goal.
Ultima's orb looks to be a solid blue. So my gradient is, I think, the biggest error.
I made the orb shape in Gimp. It's simple to do. 1 ellipse at 2:1 ratio. 1 ellipse at 1:1. Make their centers line-up, then delete the lower-half of the 1:1 ratio'd ellipse. Poof.
I created a transparent mask, too, in the shape of the same orb. That mask keeps the vertical-light-lines and the "rocks" within the orb's shape.
I think a better effect can be achieved by dropping the scaled orb, and instead, scale the mask. Behind the mask can be a simple solid blue, plus the other 2 effects.
When, if, I get that done, I'll post here.