Emeralds are a variety of the mineral beryl (Be3Al2(SiO3)6,) colored green by trace amounts of chromium and sometimes vanadium. Beryl has a hardness of 7.5 – 8 on the 10 point Mohs scale of mineral hardness. Most emeralds are highly included, so their brittleness (resistance to breakage) is classified as generally poor. The word “emerald” comes from Latin smaragdus, via Greek smaragdos, its original source being a Semitic word izmargad or the Sanskrit word, marakata, meaning “emerald” or “green”.
Color
Scientifically speaking, color is divided into three components; hue, saturation and tone. Yellow and blue, the hues found adjacent to green on the spectral color wheel, are the normal secondary hues found in emerald. Emeralds occur in a range of hues from yellowish green to bluish green. The primary hue must, of course, be green. Only gems that are medium to dark in tone are considered emerald. Light toned gems are known by the species name, green beryl. In addition the hue must be bright (vivid). Gray is the normal saturation modifier or mask found in emerald. A grayish green hue is a dull green hue. In the trade, a fine emerald will have a vivid primary green hue only slightly modified by yellow and/or blue with no visible gray mask.
Famous emeralds
- Gachala Emerald (origin: Colombia)
- Chalk Emerald (origin: Colombia)
- Bahia Emerald (origin: Brazil)
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