There are a lot of sources on how to see auras and what do the various colors of the aura mean, it shape size etc. It is said that only living beings can have auras but then how do we see food, houses and cars having auras? And then a dead body is seen to slowly lose its aura?
So here is the technical stuff. You are the ‘individual soul’ called Jivatma. You reside in this of five layered body called Panchakosh/ five-enclosures (lowest energy is Anna-mai-kosh, Pran-mai-kosh, Mano-mai-kosh, Vidnyan-mai-kosh and Anand-mai-kosh the highest energy layer). To maintain and operate this complex structure you/Jivatma take in pran/vital energy from the Universal source (Samashti pran). Pran is the real ‘food’ that your bodies need. This is the force which your soul uses to manifest everything that you see and do. The soul uses the pran through the agency of the mind (ajnya chakra creates the Moon). Thus the pran is ‘colored’ by the state of your mind.
Now the ajnya chakra, is from where the soul gives orders to the mind and also allocates the pran to various activities. Thus your mind and pran allocation is interlinked. If you are angry, the pran that you pull in from the Universe will be allocated to the lower Muladhar chakra. The instincts which will now arise from the muladhar chakra will be violent and disorganised. And your aura will get red streaks, the angrier you are the more red it will be.
The different organs of the body have their specific auras depending on the health status of the organ. If the organ is healthy its aura will be the same as the general body aura. But if it is diseased it will be black, brown, grey, red etc murky colors. And how does it get diseased in the first place? e.g. when you are angry, the entire body does not get red, there are temporary vivid streaks of red within the body. These streaks correspond to the brain, heart, adrenal etc organs. It takes some time for you to cool down and even longer for the ‘normal’ pran flow to be restored, during which the organ and its energy suffers. If you get angry frequently, the organ gets damaged more and more at the higher energy levels till ultimately the illness filters down the energy layers of your 5 layered body and manifests in the actual physical organ.
In its ‘resting state’, the aura is colorless which is often perceived as a pale transparent/whitish, this is seen only in newborn babies or persons about to leave their bodies. At this point of time, there are no thoughts, no mind in the body. The soul is busy settling into the body or exiting it so the mind as such does not exist.
When the soul leaves the body, the pran stops circulating in it but there remain impressions/ traces which diminish within a few hours. So a dead body has no aura. Preserved vegetables also have no pran/aura, try seeing the aura of preserved olives. But a freshly plucked mango vibrates with energy.
If you look closely the aura, is not a smooth layer, it is like tiny spikes which protrude from your skin. In a healthy, spiritually inclined individual these tiny spikes are rigid and straight out. Also this entire layer is quite sparkly. Tiny sparkly particles move around and also out. They look like a ‘heat-wave’, a pulsating movement in a 1-2 inch layer around the body if you observe it carefully. If someone is mentally/emotionally or physically not fit then these spikes droop and twist, there are lesser sparkles and their movement is also less vigorous. You can see this with your normal eyes with a bit of practice.
Then when in contact with other objects, like a chair or another person, these sparkles get detached from you and attached to these other things/people. That is how a non-animate object gains an ‘aura’. Your favourite chair has the sparkles from your aura adhering to it, thus seems to have an aura the same as yours! A house reflects the nature of its occupants. A temple has a beautiful aura, created by successive generations of people who have prayed there with faith, ‘heaven’!. And its exact opposite is a hospital where people are in pain or dying all the time.
The aura is never still and neither is it egg-shaped as shown in popular images. Imagine a wash of water on a paper and you put drops of different water colors in it, they gently swirl, merge, cancel out each other, move in different shapes, etc our aura is just like that. The transparent ‘resting’ aura gets its color from the myriad thoughts, emotions, actions that we perform at every instant, changing. When we are excited the aura throws out flares and swirls and its shape is further influenced by presence of other living beings nearby, or electricity in the air e.g during a thunderstorm etc. Depending on the mood of the person the aura can be very beautiful or extremely horrifying to see. These temporary moods are seen as swirls of different colors superimposed on the background of the person’s natural state of mind.
Now determined and strong thoughts are seen as defined shapes within the aura boundary of the person. But when the thought takes the form of ‘intention’, it can leave the aura boundary and move out. E.g. while doing Reiki, you intend healing and use the reiki symbols to push this thought from your aura to the client. You can see the energy of this thought moving. If you get emotional about the client even for a bit, you will see your personal energy moving from your aura to his. If this happens too often you will drain yourself. And how do you know it is your personal energy? If you have learnt to see auras by now, I hope you have first of all examined your own self and aura and know its ‘flavour’!
During Reiki initiation too there is a permanent change in the aura as the Reiki symbols are inserted deep within the energy body. My advice would be to just stick with the basic Usui Reiki. You cannot predict what can happen if you get too many symbols inside your body (karuna, etc variants).
You can enhance your aura’s strength and vibrational quality. Spiritual practice is nothing but entraining your mind to a perfect high energy pattern. Doing this regularly, you are flooding your energy body including your aura with a distinct desirable idea. Your mind ‘holds on’ to this idea. And if you can ‘color’ your idea with a golden/silvery/pearly color your practice will be even more effective.
Creating an energy shield is also important. Always visualise yourself surrounded by a golden/silvery/pearly cocoon of light. You can see out from this but nothing can see you or get in it. These colors will protect your mind and emotions from being disturbed by outside influences. And if your mind is still, you have achieved it all.