Each chakra is a transformer that generates energy of a different type and colour. The strength of each chakra depends on the person's nature and life style. Together these chakras generate the dominant hue of the aura. The main aura is photo-sensitive, it reacts and expands in light. The aura's chakra system can be likened to a tree.
Many experts suggest people can be classed by the basic hue, or the dominant colour, of their aura.
For example, Blue means a highly spiritual person, trustworthy, honest. I have found this to be misleading. The aura is a complex and changeable engine and cannot be judged so simply. The aura is sensitive to colour. It reacts to the colours of clothing and to that of its surroundings.