Emeralds are the most famous green gemstone. The word emerald is practically synonymous with the color green, and in fact, the name emerald comes from the Greek smaragdos which means “green gem.” Ireland’s nickname “The Emerald Isle” sadly does not refer to any emeralds found there but for the green scenery.
Emeralds are the green variety of the mineral beryl. The famed green color comes from chromium impurities. When beryl appears in other colors due to different impurities it is called aquamarine (blue), morganite (pink), bixbite/red beryl (red), or heliodor (yellow). Emerald rates 7.5-8.0 on the Mohs hardness scale, though it can be brittle. Emeralds are usually found in Colombia (South America) or Zambia (Africa) in granite pegmatites and metamorphosed mica schists. They grow in hexagonal crystals. The most valuable emeralds for gems are transparent rather than opaque, have few inclusions, and are a dark shade of green. Emeralds usually have quite a lot of inclusions, so sometimes people use oil to hide them, but looking at the inclusions can help you tell where the emerald came from. One final fun fact: There is even a faceting method called the emerald cut, which has a rectangular face with 8 sides. It is also known as the octagon cut. The emerald cut works well on emeralds but can be used on any gemstone, even diamonds.