Emerald is the bluish green to green variety of beryl, a mineral species that includes aquamarine.

ABOUT EMERALD
Gem experts differ on the degree of green that makes one stone an emerald and another stone a less-expensive green beryl. Most gemologists, gemological laboratories, and colored stone dealers call a stone green beryl when its color is “too light” for it to be classified as emerald. Even among that group, however, there’s a difference of opinion about what’s considered “too light.”

Fun Facts

Age of the oldest emeralds, from South Africa.
Pharaoh known for her passion for emeralds.
2011 sales price for Elizabeth Taylor’s emerald pendant –  a record $280,000 per carat.
Birthstone May
Anniversary 20th and 35th wedding anniversaries
Mineral Beryl
Color Vibrant green
Refractive Index 1.577 to 1.583
Birefringence  0.005 to 0.009
Specific Gravity 2.72
Mohs Hardness 7.5 to 8