Take a look at this video on CNN, which shows a whopping 25 Lb faceted Emerald:
http://www.cnn.com/video/#/video/international/2012/01/17/can-twenty-five-pound-emerald-found.cbc
The Emerald, which is from Brazil, is definitely large, and it has the emerald-green color. However, it lacks transparency and is not gem-quality, so it is not quite as outstanding as the video makes it out to be. Still in all, it's mammoth size is unprecedented, and the Emerald crystal from which it was faceted must have been quite a piece.
