Maybe it's the UV spectrum of sunlight that reacts to em, as you put it exactly how like the transition eyeglasses work. Since the ones i the sampe pics are clear those would have to be shots taken unde just normal indoor lighting, pity hey didn't show any samples under sunlight to see how "purple" they get.

As it stands though you're right about that UMackness ( and a very good pint!!) I wouldn't want to display my toys under sunlight, so this wouldn't be a good item for diorama - Ill just settle for the energy cubes (as seen in my sig) I have bought before - pre-colored so no need for sunlight heheheh