The most important "secondary" chakra sites are in the feet and the hands. Since my bias is to move from the Earth upward, let's start with the feet.
The foot chakra rests between the ball of the foot and the large pad just before the toes. I've never seen a color, nor read about one, associated with this chakra. As with any other chakra, this appears as a spinning wheel and can be open, closed, collapsed inward, or pushed foreward. The foot chakra's purpose is to be a secondary grounding site; it is also a place to touch Earth energies.
The hand chakra appears in the palm of the hand. Again, there is no color attached to this chakr. The hand chakra, in some systems, is attached to the heart chakra by an energetic pathway that leads up the arm to the heart. This chakra brings energy in, and also sends energy out. In massage therapists. touch healers, and energy healers, this is the spot where healing energy leaves the body system to move into the client. When you first experience energy in your body, frequently this is where it happens. You can even feel it yourself by doing this exercise: rub your hands together until your hands feel warm. Rest your hands, palms together. Then very slowly move your hands apart. You'll feel a subtle buzzing: that's energy.
Information on these chakras specific to rock musicians can be found at: www.myspace.com/duffimac in the blog