The human aura is fourfold and consists of the health aura plus the emanations from the etheric, astral and mental bodies. (From "Esoteric Healing" by Alice Bailey)

From the writings of the Master El Morya:

In"Agni Yoga":

"......when the tensed aura attracted the Fire of Space and enveloped itself in greater luminescence....this is how one's physical link with the finest energy is established."

".....abrupt movements disturb the motion of the aura and we avoid them. A speedy rhythm does not disrupt one's link with the atmosphere, but convulsive movements wound the aura, like needles."

"Recently, also, the purple protective auric net has become known.... related to the domain of Fire. The (auric net) represents the power of Fire, which is attracted from space by the healthy emanations of the bodily organism."

"Between the two Origins - Light and Darkness - the protective auric net shines like armour. Truly it is the boundary between Light and Darkness!"

"....psychic energy will be strengthened under the waves of fire, when the aura begins to take on a purple colour due to tensity. It will become refined...."

"Harmony of auras does not require sameness of colour. Thus, a violet aura can be in harmony with one that is green, and a pink aura can make a blue one more visible...."

"Among the components of developed auras it is especially rare to see the emerald green and the noble ruby colours, which stand in contrast to each other. The first denotes synthesis and the second, the self-sacrifice of attainment. In clouded auras hints of both may be seen, but to see them pure is as rare as are synthesis and attainment themselves. Emerald is closer to the Chalice, and ruby to the Eye of Brahma."

"The Fire of Space, in rare cases, can be observed by the naked eye where it is more dense, near the protective purple border of the aura. Space becomes, one could say, filled with small tongues of flame. But for this manifestation a strong aura is needed, which will not suffer from the proximity of the intense flame."

In "New Era Community":

"Indeed....the correlation of auras with the spatial substance gives quality to the result. Precisely, not the size but the colour gives a particular approach to the action. The size of the aura will give tension to the action, but the path will be determined by the colour. Thus it is impossible to set any specific way of action under an alien colour combination. A casual predetermination causes a mixture of rays and paralyzes the will. The infirmity of many workers is explained by the mixture of heterogeneous colour groups. Here would be very useful a simple physical apparatus for the determination of basic radiations."

"To observe the movements of the consciousness one should take photographs of physical radiations....there may be observed blue spots floating in the field of radiation...the consiousness is being condensed in these moments.....flaming streams sweeping away the blue condensations, which means that the hero is ready for the next acheivement...."

".....what direct arrows spurt from the shoulders of the leader for the General Good, and what purple waves flow outward in defense and engender new might! But the radiation of a babbler is furrowed with zigzags, the ends of which turn inwards. Apparatus for photographing the physical radiations will soon be given to children..."

In "Leaves of Morya's Garden" vol 2:

"Let us speak of the auras. The egg-shaped aura is natural to the astral body. The most usual, the narrow aura, which emanates from the entire body, extends outward about two inches. In accordance with the degree of spirituality, it begins to expand from the upper nerve centres. Starting from the solar plexus, it afterwards rises toward the brain centres, forming the so-called solar aura. Influxes of blood are characteristic of the transposition of the aura, when the current of tension shifts its pressure. Even fainting spells are possible. Finally, the radiation leaves the lower extremities and forms a surrounding ring. The organism while yet in the midst of life becomes acutely sensitive, especially to sounds and colours. The utmost tranquility is needed during this transitory period. The solar aura may be of ten or fifteen inches, and of course its dimensions may increase. In spite of the discomfort of transposition of the aura, one may congratulate him who has acquired the upper radiation. The opportunity for repose should be cautiously created. Later on a seeming new armour grows, as the nerves of the skin become strengthened. One cannot exactly divide the physical and the spiritual. The balance fluctuates and the waves travel over the organism. This must not be called a malady, but the organism must be assisted every moment to fortify itself in its new condition. "