Everything in the Universe is made up of energy vibrating at different rates. These different speeds of vibration give us both color and matter of different types. The human eye can see light that is vibrating in the frequency range of 400nm to 700nm. This gives us the colors of the rainbow from red (the lowest vibration) up to violet (the highest).
Color surrounds us in everything we do, in the environment around us, in the clothes we choose to wear, even in our food. The colors that surround us have a huge effect on our moods and our motivations. Color also shades our language with meaning. The black gloom of death, the yellow of cowardice, the green of wealth. No matter what we are doing it is impossible to escape the meaning and depth that color gives to our lives.
While symbols are the heart of the meaning of any Oracle Card, the color they are depicted in is the shades of that meaning. A red heart is burning passion, where a pink heart is the softer more gentle and less noticeable compassion.
When you are able to look at the symbols in Oracle cards and the overlay that with the meaning of the colors that they are depicted in, you add shades of nuance and layers of depth to your Oracle Card readings. Taking the time to learn what each color is saying to you gives your intuition another tool to use when you consult the cards.