Emerald is the bluish green to green variety of beryl, a mineral species that includes aquamarine.
Emerald is the green to greenish blue variety of beryl, a mineral species that also includes aquamarine as well as beryls in other colors.
Gem experts differ on the degree of green that makes one stone an emerald and another stone a less-expensive green beryl. Some people in the trade tend to give the name emerald to any green beryl colored by chromium. But to most gemologists, gemological laboratories, and colored stone dealers, it is more correct to 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."
GIA uses lab-graded comparison stones to determine if the green color is dark enough and saturated enough to be called emerald.
BIRTHSTONES & ANNIVERSARIES
As the gem of spring, emerald is the perfect choice as the birthstone for the month of May. It’s also the gem of the twentieth and thirty-fifth wedding anniversaries.
WHY WE LOVE THIS GEMSTONE
THREE-PHASE INCLUSIONS: Three-phase inclusions in Colombian emeralds contain tiny crystals of rock salt, liquid, and a bubble of gas.
HEXAGONAL CRYSTALS: The best emerald crystals are gorgeous flat-topped green hexagonal columns that are as beautiful as faceted stones.
ANCIENT EGYPT: The first known emerald mines were in Egypt. It is believed that these mines were worked as early as 3500BC.
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