Emerald is the green form of the mineral beryl.
It has a hardness rating of 7.5-8 on the Mohs scale, making it one of the most durable of the most recognized gemstones.
The term emerald probably originated from the Greek word for 'green gem', smaragdos. The gem occurs in many shades ranging from yellow-green to blue-green. The green color of the stone results from the small quantities of chromium and vanadium found in the crystal structure of emerald.
Beryl crystals can only be considered as emerald when the tone of the gem ran...