Very Nice Minature - Love the whole idea and the pose - best idea for basing i've ever seen. I like the gem contrasts with the rest of the minature & looks like really arcane technology!
Personally I love the jumping-off-a-cliff pose. Only I'd try to point his face and eyes looking down at whatever (whomever) he's jumping ON. The gem is fabulously painted but in a bad place. First it distracts from the face of the marine and second it just doesn't make sense there.