That's an interesting way to do it, Keith: pretty cool.
For the "theming" of the various colors, yes there's several different things (some in and some not):Red
Fire obviously, but also bits of light to a much lesser degree. In general a theme of power and destruction, etc.Green
This one is split very majorly. On the one hand, you have the whole animal/plant/alive-things theme. So most summon spells are here, for example. On the other hand, this is also the earth category. So you get some degree of power-type spells that overlaps with red a bit, and which in general is themed around dirt and rock and earthquakes and stuff. Also, since this has an alive-things theme, this is also the main healing color.Yellow
This is both air and lightning, in a large respect. So anything stormy, or electrical, and so on. It's also related to things that are robotic but NOT clockwork. But for robots, they tend to be yellow-based but also yellow-weak. This is also the color from which all transmogrification spells will go: if you're changing your form, that's air-related for reasons I forget.
Oh, and most of the movement-related augmentation spells also go here. Those that actually push you physically around, I mean, not those that teleport you.Blue
Split again: both water and ice. Some extensions of that are obviously slowing type effects for ice, but you also get into area-of-effect type stuff with water "washing over" multiple enemies in a row, etc. AOE damage isn't unique to this color, naturally, but I intend it to be a larger theme here than in some other colors. Most colors will do all the basics in terms of general types of spells (piercing, AOE, melee-range, long-range, defensive, etc), but as you get more advanced spells the idea is that some colors do certain things just plain better than others at those higher levels. Which mostly aren't in the game yet when it comes to that sort of thing.White
Light is primarily focused with things that are... light-related. Illuminating dark areas is one major theme here, but you also get things like changing the time of day, or in fact even any sort of time-manipulation stuff in general would go here because of that (sun cycle, etc, being the reason). I ultimately want light and darkness to play a more major role in parts of the game, but right now in some respects this is kind of the most generic color when it comes to combat. It needs a little something else, but I'm not sure what. Some kind of clerical and "good" effects could also go here. Like the ability to peacefully send vengeful ghosts to rest without "killing them again," etc. Any sort of "pacification" stuff would go here.Purple
Entropy is the theme here, and that is expressed in a couple of ways. First off, you have have the obvious "evil" angle. Stuff centered around death, etc. But this isn't like a necromancer class or something, and it's not the main meaning of this color, either. It's primarily focused on the decay and reorganization of matter/energy, which is why entropy is what we call it. So, sure, death fits under that banner. And some powerful death spells fit here (and spells that use your own life force to damage the enemy would also fit here tidily). But shrink, seize, and teleport also fit here logically, because all of those are transforming the states of matter and energy of other objects in powerful ways.
Good question! This should probably be cleaned up a bit and moved to the wiki, actually.