For my own entertainment, I have been designing how I would hypothetically make a spiritual sequel to Arcanum: of Steamworks and Magic Obscura. It is hypothetical as the work needed to do it right is beyond my abilities and resources but not my imagination. THE major interesting feature of this game was the interplay between magic and technology which are largely mutually exclusive/antagonistic in this world. The flexibility of a mage compared to the difficulty to achieve mastery in any area for a scientist meant that the game was a lot easier for the first group but boring to play multiple times as a mage. I usually write Sci-Fi stories (and do nothing with them) which means I automatically wanted to find a systematic way to handle magic which is significantly different from the original but would solve these issues.
All magic in this world by my current plan has a color and difficultly. Whether a mage can cast the spell is dependent on his color (no not race) and power. I wanted color to be described by 6 cardinal directions which in the simplest case is an octahedron.
One of my main hopes was that the appearance and interface would change depending on the character's expertise in a given area. It would start and octahedron far any user. As magic developed would become a triakis octahedron. By end game, it would be a constellation, geometric design, flame like fractal, crystal, lightning branching structure, etc. depending on the mage's particular aptitude. This means for a powerful mage, the auras would become the major aesthetic difference from the increasingly detailed gritty, steampunk appearance of the world from the eyes of a scientist.
For magic, the most obvious directions would be fire, earth, water, air, light, and darkness. The point is that a mage could cast pure fire or pure light spells but not pure light and dark spells. Any electric, lava, astral projection, life, or healing spells would be combinations of these. The issue is, I need have appropriate real colors which correlate with each of these. Unfortunately, the colors that first spring to mind are red, brown, blue, light blue, white, and black. These will not work well.
What am I asking for?
I want a (preferably) continuous map of magical abilities that has a superimposable color map. The idea is that from the level/size of the aura and the color of the aura, an experienced oberserver can know which spells (that the observer knows about) the mage can cast. It must be inherently designed such that no mage (no matter how powerful) can become a master of all areas of magic. Spells analogous to those from the original game's colleges (listed below) must have an intuitive place of the map. The map should attempt to distribute these over the map as uniformly as possible so one particular build is not overpowered. The designer is free to add additional (but logical) spells or colleges, break up colleges, or revise them to make this work out better/easier. Ideally colors should aethetically mesh with the type of spell in that area.
- Conveyance (telekinesis, space warping, and teleportation)
- Divination (detect magic, see contents, identify magic properties)
- Force (electric, force push, disintegrate opponent)
- Mental (charm, control will, stun)
- Meta (magic about magic such as silence or reflect spells)
- Morph (turning things into other things such as opponents into sheep)
- Black Necromancy (talk to dead/trap in rotting corpse, raise undead, extract soul to kill)
- White Necromancy (heal, resurrect, essentially nice versions of necromancy)
- Phantasm (light based spells such as blinding flashes and illusion casting)
- Temporal (time based magic such as slowing enemies while speeding allies up)
I have included my best answer thus far but am not satisfied with how certain etherial magics (meta, mental, temporal, conveyance) fit into it. I am also uncomfortable with what type of magic should be purple (or how else to jump between the red and blue without going green). While that answer attempts to address it, I believe that one side of the map is very unbalenced.