Two Theories on what the Color of Orbs Mean
Chromatic Distortion: The color difference in orbs is caused by chromatic distortion. Our eyes perceive different wavelengths and shapes as varying colors. If a particle happens to be of a certain makeup or shape, it will tend to absorb certain wavelengths of light and reflect others. That is what gives us the perception of a color.
Personality or Mood of the Energy: Some paranormal experts believe that the color of the orb is influenced by the energy of the spirit who is the orb. Some people believe that it shows the energy’s personality or moods.