We now live in an era when the scientific model is shifting to quantum physics and a new paradigm of an energy based reality, this welcomed change not only opens up many new possibilities, it also heralds a re-discovered in the validity of an holistic approach to all life. One that validates life forms as energy based organic bio electric organisms.
An aura is what we refer to as the etheric energy body, and is the energetic space that is around us, that is non physical, it consists of excited atoms and molecules, and is considered to be the fabric of consciousness its self. From seeing the colour energy image on the left we can see the light from the Sun being split to show us the seven rays of visible colour, a rainbow.
All auras are different in, form, colour, strength & density they are a energetic representation of many aspects of your physical, emotional & spiritual self, and can change on a regular basis. However some characteristics tend to stay reasonably consistent which is dependent on the personality traits of the individual. If you are of a stable well balanced disposition then I would expect to see a consistency in your general underlying colours, but if you are less stable and enduring a difficult chapter in your life then many elements of your aura can become unstable & changeable.