Colour is a very important part of energy work, because each colour represents a certain vibration that has different effects on the body, mind and soul. Even if one cannot 'see' the colours (clairvoyance), often you can 'feel' them or merely 'know' (intuition) what they are. Also, if you are having trouble deceifering the colour-vibration, just try to notice how you feel when you hold the energy.
I urge you to experiment on your own before reading this. The fewer expectations you have, the better.
Red: This is the colour of courage, instinct and impulsiveness. It feels active and lively when one moves it. It should be a bright colour that is easy to shape and mold. Because it has one of the slower vibrations, one can often feel it in the hands as a warmth or tingling when it is balled up. This colour should be used to give people courage when they are afraid, but only in small doses, as it can make one jumpy, sleepless and impulsive when making choices.
Pink: Pink is a wonderful healing colour. This colour heals physical ailments in a loving and kind way. It feels warm and delicate (like silk) and floats easily around. The darker the pink (though not dark enough to be magenta) is, the better healing it will put forth. This colour is good for people who need physical healing (of any kind) or those who need love. This colour is often seen as a cord between people who love eachother.
Dark Red: Dark red is often associated with anger, but it not all negative. This energy is much heavier than normal red and has a much slower vibration. Although it is 'thick' it is not hard to remove fom the body or mind. Anger could be directed toward an injustice or toward an evil in the world and may cause the person to fight to help others. This can also be seen as passion.
Magenta: Magenta has a sort of slow choas effect to it and is kind of like a foggy liquid. It's room temperature (I guess? heh) and doesn't stick too easily to other energies, especially more energetic ones. It helps with impulsivity (in terms of the physical world) and seems to relieve people of nervousness. Usually. It isn't all that reliable, though...
Orange: Orange is a vibrant, exciting colour that feels heavy yet playful. Orange is good for people who need courage for an action that they want to do (such as performing on a stage or riding on a roller coaster). This energy makes one excited and couragous enough to do anything.
Deep Orange: Deep orange gives one confidence and self-esteem. It feels slightly cool to the touch, but pleasently so (imagine taking an orange out of the refridgerator, lol).
Yellow: Yellow is a happy, lively and clingy energy. It easily stick to people (ever hear, 'happiness is contaigious?') and fill them with joy. People who are feeling sad often welcome this colour's energy because it has an immediate affect of cheering someone up.
Gold: Gold is the universal colour of love and healing. It is the strongest healer you can find and heals mind (emotional), body (physical) and soul (spiritual) easily. It energizes a person and no one block another of Gold energy. This is God's energy. It feels very light, easy to lift and move and often does so on it's own -right toward the one who needs it!
Mustard: Mustard is a colour of jealousy and of bad intentions that are just starting. People who lie often carry this colour. Mustard feels cold and slimey, and usually wet.
Green: This shade is mentally stimulating. It feels cool and fizzy to the touch and has a very active movment. It often finds it's way to the place you want it very quickly, though sometimes it can be hard to grasp.
Emerald Green: Emerald is a shade of green that is most often associated with Archangel Raphael and his healing. So, of course, it is a good healer of both emotional and physical ailments. It often feels slightly waxy to the touch but is enjoyable to hold and ball up.
Blue: currently being debated...Light Blue: This is the colour of emotional healing. It feels like water (not cold, not hot) that can be lifted like one would a thin scarf.
Indigo: This is the colour of knowledge, knowing and true awareness. Indigo feels strong and it holds together well. It's warm and tingly to the 'touch'. This is often within people who are either fully Indigo themselves or are witnessing a psychic 'jump' in energy. It stimulates the Third Eye and allows clairvoyance to work more smoothly. It's very powerful.
Violet: Violet works like one's conscience when used on a human. It is often found in people who are passionate about the environment, human/animal rights, or other things... it is a powerful colour/energy that can help someone see other sides of arguements or give them courage to stand up for others. It feels slightly heavy and warm but sticks together quite well.
Lavender: Lavender is very effective for helping someone to lift out of their body, either for astral travel or just sleep. It's very helpful for insomnia. It feels cool and airy, and lifts like a thin tissue.
White: White is a mixture of all colours. It is very active and flowing, often seeming more like a gas than an energy, athough it sticks together amazingly well. It acts in many different ways, depending upon one's intention...
Clear: Although many do not know clear is a colour in energy healing as well. It is seen as floating, sparkling ribbons or scarf-like pieces.
Grey: Grey is the colour of sickness. It is usually heavy or sticky and hard to remove from the body. Depending on how dark and/or heavy the energy is, the severity of the illness varies. It could be a cold, the flu, or even cancer. Watch where the energy is situated and/or moving to and look for physical signs in those places.
Tan: This colour is usually very organized and... sort of cubic. It isn't very malleable and tends to stay in one shape. It seems to help create structure in the energy around it as well.
Brown: still being figured out, heh...
Black: Black is the colour of general negative energy. It's VERY heavy, very sticky and very hard to remove (though less so than Grey). Often, Black is with another colour, such as Red (possibly anger), Mustard (possibly jealousy), Grey (possibly sickness or depression) or any other. Black is usually created in a person when something bad happens that makes them angry or depressed or jealous (ect...) and it is stored in the body until it can be released or converted. Everyone has a little black, but too much can slow one down and trap energy.