Emerald is the bluish green to green variety of beryl, a mineral species that includes aquamarine.
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, theres a difference of opinion about whats considered too light.
At 7.5-8.0 on the Mohs hardness scale, emeralds are harder than many other gemstones but less durable than diamonds, sapphires and rubies. They are an excellent choice for jewelry that will last through the years, provided they are taken care of.
The most popular metals for emerald jewelry are platinum and yellow gold. The durability of platinum protects the green gemstone, while yellow gold emphasizes its rich hue. Emerald is a very versatile gem, popular in classic, contemporary and vintage jewelry designs. It is also a stunning choice for engagement rings.