This is Rococo Darkest Emerald Luxe and Revlon Colorstay Rain Forest:
Viridian, in fact. They both sort of look grayed out and blue-green in my swatches, but this one (Darkest Emerald Luxe) a little less gray than Veridian. Rain Forest, on the other hand, is both a bit brighter and a bit more yellow. Both of these polishes have a lot of shimmer. Rain Forest is not from the current Colorstay collection (which is Gel Envy) but the one before that, so it's been discontinued for a couple of years now. I bought my Rococo polishes from Space.NK back a couple of years ago, and a quick search didn't find much for them, so I'm not sure they're still around, either. Definitely Space.NK is not selling their nail polish any more.
(I'm still mulling over the emerald question, so I googled, and here's a company that sells actual emeralds. That's the color I was thinking of - also the color of the Emerald City in the Wizard of Oz, which is about the same. It's usually got some blue to it but it's brighter than most of these nail polishes with emerald-related names.)