What are the 9 colours related to Goddess Durga in Navratri?

Navratri, the festival dedicated to Goddess Durga, began today and each day has a special colour dedicated to different 'avatars' of Goddess Durga. The colour for the first day is yellow, second day is green, third is grey, fourth is orange, fifth is white, sixth is red, seventh is royal blue, eighth is pink and ninth is purple.