Emerald is a sexy green color and is the official birthstone of May. It is also used for the 20th and 35th wedding anniversary.
Although Emeralds are known for being various hues of green, the darker colors are more prized while the lighter versions are only called green beryl. In the gemology world there is a considerable argument as to at what point an emerald is dark enough and what is considered too light to be considered a true emerald. Aquamarine is a blue/green variant and Morganite is a pink variant.
The Egyptian queen, Cleopatra, had an absolute passion for emeralds and was in love with the bright green color. She wore lots of jewelry with Emeralds and even had her portrait carved in it. The color green is known to relieve stress and eye strain and in ancient times it was believed that staring at a emerald would bring comfort by removing weariness and lassitude.
Mineral Group: Beryl
Refractive Index: 1.577 to 1.583
Birefringence: 0.005 to 0.009
Specific Gravity: 2.72
Mohs Hardness: 7.5 to 8.0