Pink
Raised from childhood for the pleasure of the high Colors. They're property, and they know more than anyone how to read a powerful person. A number of them learn to do something about it.
They do not have the Color-name particles the higher Colors use. Matteo, Evey and Theodora all show what they can become.
Their beauty is made deliberately fragile. Darrow sees that they're built that way.
Darrow encounters them first as furniture at a Gold party and only later as people. His friendship with Matteo, who teaches him how to pass among the Golds, is among the first signs that the revolution will need more than Reds.