"The green coloration in Crested Geckos is produced by two or more different colors combining to create a green coloration. Crested geckos do not actually have any green pigment and they also lack any blue pigments."

Found that here:
http://www.pangeareptile.com/morphs_colors.htm

Those cresteds look awesome! I can now say that green cresties are my favorite colored cresties out there! lol