Very few people have witnessed or reported what they saw as they saw the aura leaving the physical form. A friend of mine said he felt the aura of a dying pet pass through him, as if some sort of electrical/magnetic energy passed through as it rose up into the air. Others have reported seeing a wispy smoky substance rising up into the air as a person departs. However, the most detailed report I have found was by Robert Bruce at http://www.geocities.com/athens/parthenon/6670/doc/t_auras.html where this description of patients dying of cancer and other terminal diseases can be found:

"…Their aura undergoes dramatic changes…in the weeks prior to their death…. when the aura fades and begins to grow weaker and paler… A week or so before physical death, the aura begins to expand and change. It changes into a beautiful (very pale) milky-blue, shot through with faint, tiny, silver and white sparks. These sparks flash and twinkle throughout the aura. Each spark is only visible for a fraction of a second at a time…. Note: The aura of a dying person is a very pale milky-blue. It is VERY pale and faint and VERY difficult to see. It is quite common to see a pale-blue aura surrounding a healthy person, and this does NOT mean they are about to die. The aura of dying person is quite different from a normal, healthy, pale-blue. It is all one colour, much larger than normal, very milky and very faint.

"Closer to the time of death, the aura begins to pulsate, swelling and shrinking erratically. At times it will fill the entire room, becoming more of an atmosphere than an aura. At other times it will be so shrunken as to be almost invisible to auric sight. It grows paler and finer by the day, and the tiny silver and white sparks become finer and increase in frequency.

"There is a great deal of activity in all the energy centres, at this time. The energy body is preparing itself for the final separation of the physical body from the non-physical body (or spirit). There are, at times, faint surges of colour and faint coloured sparks, like pastel fountains, surging and falling from the primary centres. They spasm and shudder and begin generating a much higher and more refined type of energy. This change heralds the imminent and final separation, of the spirit from the physical body—what we call death.

"At some time (variable) before physical death, the aura will become almost invisible to auric sight. Only a faint, very pale glow will still be seen, close to the skin. This is residual etheric matter, clinging to the physical body. There is, however, still intense activity going on within the energy body, but this is now far beyond the reach of normal auric sight.

"At the actual moment of death, if you are watching closely, you will see a very faint, pale mist, surge up out of the body, and quickly vanish. This is the spirit leaving the physical body. That faint mist is residual etheric matter, clinging to the spirit body, as it departs.