There are many kinds of auras. The most common which is usually characterized by color is the emotional aura, which every person has.
General color coding is this:
Gold - very close to higher power by state of mind and with good intent
Green - close higher power by state of mind and with good intent
Blue mixed with green - Unsure and off balance, often confused and lost
Blue - drifting away from higher power and often with ill intent
Purple - far from higher power and with evil intent
Red - very far from higher power and with evil intent, often demon possessed.
Colors may vary from person to person and blend more or less, but that's the basic of what I see. Since I don't have your eyes I can't say what you'll see for certain.