You are assuming that a random mutation will cause all colors to be equally likely. But, AIUI, there is a reason that all your standard chemical powders in a n

You are assuming that a random mutation will cause all colors to be equally likely. But, AIUI, there is a reason that all your standard chemical powders in a normal chemistrly lab are white; colors are a rare side effect of certain molecular properties. Most chemicals, variated randomly, are extremely boring colors, mostly white.