Certain colors of spice are more rare than others, but they mean different things to different empires and colonies (GamingSteve.com). I haven’t really figured this out yet, there seems to be a lot of different colors. The Spore Guide indicates that the star colors of different galaxies have a meaning: Blue stars have planets rich in spices; Yellow stars have planets with a good amount of spices, and Red stars have planets low on spice.
Now, what do the different ‘Wild’ icons mean when a planet is inhabited by wild animals?