7f6ac405_Reading_Auras__Clear_Bright
[Colour] Flames or Other Energy Forms [Muddy/Dark] See first column. [Clear/Bright] 
This doesn't actually indicate any color, but rather a energy form. If the aura looks as if the person is surrounded in a corona of flames, of any color or colors, then it may indicate great personal power or that the person is an avatar of some kind. As well, some people's auras may not be humanoid. They may be specifically shaped into things for different purposes, or many naturally be that of another creature, as is common with Otherkin.
Reading Auras
Clear/Bright