During the anime and the manga, the author refers to Midori as green-skinned, in fact, even her name means green. But she doesn't look obviously green:
I would expect a name like Aoi instead if there was some leeway - http://www.omniglot.com/language/colours/japanese.htm
In the manga there is a panel with RGB codes, I thought I'd color her in just to make sure it wasn't an anime adaption problem & I removed the shading:
Midori's skin is hex value #85D8D0 or RGB (133,216,208). The green component of her skin is only 8 units larger than the blue component. Thus, even without my subjectiveness, she can't be considered green-skinned. Several color-focused websites classify the color as Cyan, not a shade of green.
Is there some reason for this - maybe based in language? Why didn't they just say she was cyan / aqua / turqoise? or even, blue?