Oh, no, did I miss all the fun? ;-)
Sam, mine (the males) usually look black all over, but with the right light the iridescence is turquoise or green on the throat, purple on the crown, and emerald green everywhere else. I have some pics I can show later.
I'm not a hummer expert by any stretch, but I would not think this one is the same bird I see!
EDIT Here are a couple of photos. I'm not much of a photographer but you can see the overall coloration. I don't know about any Costa Rican subspecies; couldn't find anything in my guides.