Does snow have any pigment?
The white colour simply means that the entire spectrum of the light is reflected. This is because there is no pigment that absorb a specific frequency of the light. When you see a red rose, it is because its pigment absorbs the complementary colour of red, namely green. The reason polar bears look white is not because of a pigment but because their fur is transparent. It also means that all the light spectrum is reflected and it looks white.
