This description below is not exhaustive but gives you a preview of what you are to see and "see"
BLACK:
Yes, black is very confusing of colors in the aura. When I generally see black within ones aura, I know that this individual is shielding him/herself from outside energies. There is nothing wrong with black in the aura unless it is to extreme. And with all colors, being all one color is an indication of being unbalanced. Black can also show that one is hiding something and keeping secrets. Children who are abused usually have a black ring around their aura, while event the adults who haven't come to terms of their abuse will continue to carry that burden of the black ring until they have therapeutically dealt with the past.
WHITE:
Rarely seen by itself, white reflects Truth and Purity. Babies tend to have total white auras and those who are at peace with death too.
If you and I were pure, that’s that color that our aura would display. All the great masters have white as Aura. Krishna, Jesus and Buddha (to mention a few) had (and still have) a white one. Besides, they are most of the time depicted with a white light emanating from them in paintings and drawings. Those who met them as Spirit guides will also be able to confirm that fact to you.
A “halo” is just another name for aura. If you notice somebody with a white aura, make sure you follow them as you will learn tremendously from them regardless of what the outer will display. That’s another characteristic of the great ones as well, they rarely appear as people would expect them to appear. That maybe because they want us to raise above our prejudices and preconceived ideas in order to approach them….
White as an aura color is here to remind us of Perfection and striving towards it in our spiritual unfoldment.
GOLDEN:
A brighter than yellow color sometimes within one's aura will indicate that the person has a lot of spiritual energy, and is in tuned with him/herself. The muddier gold coloration can indicate that one hasn't come to terms with the higher inspirational side of him/herself.
In a word, it describes most of the time Wisdom.