What do the magic item colors mean?

the-elder-scrolls-v-skyrim

In my travels, I've found numerous magic items. These items have a color (so far only red, green, and blue). For example, the Thieves Guild armor (which can't be disenchanted for some reason) is green, items I've enchanted are blue, and some random items I've found are red.

Is there any meaning to these colors (maybe relative power level)? Has the Skyrim Creation Kit shed any light on this?

Nils Munch is mostly correct: each enchantment uses one of a number of shader effects (as they're called in the Creation Kit), but the Creation Kit does specify which shader goes with which enchantment.

Categorizing them by color, here's what I found:

Blue (Dark)

Absorb Magicka
Damage Magicka
Fear
Fortify Alchemy
Fortify Alteration
Fortify Conjuration
Fortify Illusion
Fortify Magicka
Fortify Restoration
Muffle
Regenerate Magicka
Resist Magic
Turn Undead

Blue (Light)

Fortify Shouts
Frost Damage
Resist Frost

Green

Absorb Stamina
Damage Stamina
Fortify Archery
Fortify Barter
Fortify Block
Fortify Carry Weight
Fortify Heavy Armor
Fortify Light Armor
Fortify Lockpicking
Fortify Pickpocket
Fortify Smithing
Fortify Sneak
Fortify Speechcraft
Fortify Stamina
Paralyze
Regenerate Stamina
Resist Disease
Silent Moons Enchant
Smithing Expertise

Orange

Dawnbreaker
Fortify Destruction
Fire Damage
Resist Fire
Trollsbane

Purple (Dark)

Resist Shock
Shock Damage

Purple (Light)

Bound weapons
Soul Trap

Red

Absorb Health
Banish
Fortify Health
Fortify One-handed
Fortify Two-handed
Fortify Unarmed
Regenerate Health
Resist Poison
Waterbreathing

From looking at this list, the colors are, for the most part, intuitive:

Blue: Stuff related to frost, magicka, most of the magic skills, or the undead
Green: Stuff related to crafting or the stealth skills
Orange: Stuff related to fire or destruction
Purple: Stuff related to conjuration or shock
Red: Stuff related to health or the combat skills

Of course, there are exceptions and liberties Bethesda took based on whatever aesthetic choice they decided to make.

There's also the case of items having multiple enchantments: the game chooses only one of the enchantments to display as the effect. However, it's not clear to me which one it chooses: I suspect it's either the first in the internal enchantment list or the last.

Every enchantment has a matching particle effect and reflection filter.

Also the enchantments you might not have access to.

Which colors and strengths that goes with which abilites is up to the Game Designers (Bethesda).