SCALZI is ... well I mean obviously it's a very literal (heh) interpretation of the cover of the first edition of Old Man's War. More prosaically, it's a bright mid ultramarine base with moss and sea green glitter, green opalescence, turquoise sparkle, and a yellow-green glow when the lights are off (kinda like how the cat-esque eyes of genetically modified supersoldiers might appear).
You've already read the Old Man's War series, right? RIGHT? If you haven't, get on it. Wildly entertaining AND thought-provoking, it's a pretty compelling vision of far-future warfare, politics, and self-determination versus the ... wow, I'm making it sound super fucking dull. Just read it, okay?