Every substance on the planet has a field of energy around it. Even what you see as substance is energy. The whole of existence is energy.
One part of energy has manifested itself into a certain level of reverberation which makes it a physical form. The other part of energy also has a form. That form which is not physical but still maintains a form, is being called aura. It is a field of light and energy around the body. Essentially, the physical, mental, emotional and energy status of who you are right now is represented by your aura in a certain way; it is visible through the aura.
Auras are of many kinds. One can carry anything from a pitch black aura to a pure white aura. Between these two, there are millions of shades. In all this, only two types of auras are of significance. When you are in a state of realisation, your aura will be pure white. When a yogi who has experienced realisation chooses to make himself dynamic, the aura will become electric blue. It is in this context we refer to certain great beings of the past as "the blue ones".
For different requirements, one may change the nature of the aura. The energy is different. The aura is different. The person is different. Everything is different. Because, to do a particular kind of work, you need a certain kind of aura. The aura is just an indicator. The aura is not the real thing.
Don't try to see people's auras. The aura is the periphery of the person. Look a little more at the core of the being rather than looking at the surface. The surface is for doctors because they want to fix a physical part that may be going wrong. The surface should not be the interest of a spiritual seeker. What you call aura is even more superficial than the skin because it's even further out.
It is said that "beauty is skin-deep". A certain type of beauty is skin-deep. If you see someone with skin peeled off, you wouldn't think she is beautiful. But the aura is not even skin-deep, so it is not worth spending time on it. If you become conscious of the core, the surface may be visible to you, but trying to see and read people's aura will be a waste of your time. If your perception is enhanced, you may see things. It is good to see things which are there. If you start seeing things which are not there, that's the first step towards insanity. So you must be focused on the core, not on the surface.
All those who believe they are spiritual but who are really not, they are the biggest deterrent for others to seek any spirituality. Because of too many people like this, right-thinking people who are a little more sensible don't want to have anything to do with spirituality.
If you have the necessary insight, the aura may give you access to the nature of the person, but you are only looking at the psychological, emotional and physical structure of the human being. On the spiritual path, it is best to ignore the aura ^ yours and everybody else's ^ and focus on the core. If you are focused on the core, you will have a wonderful aura. If your focus is on the surface, you will have a miserable aura. So don't keep looking at your and other people's auras. It's time you looked at the core of yourself and the other. If you look at the core of yourself, then naturally you will see the core of everything because in the core, "this and that" does not exist. In the core, only "this" exists. Only on the surface, "this and that" exists.