Table of Contents
Introduction
Beryl represents an entire family of rare gemstones, with the most famous member being the green beryl known as “Emerald.”
Among the many green gemstones, emerald is the most historically renowned, recognized across different cultures and eras. Even today, the term “green gemstone” is often synonymous with emerald.
Emerald is the most significant member of the beryl family, a precious gemstone and the representative of green gemstones. Alongside diamonds, rubies, and sapphires, it is regarded as one of the four most valuable gemstones in the world.
Emerald
- Crystal system: hexagonal crystal system
- Hardness: 7.5~8
- Specific gravity: 2.67~2.78
- Luster: Vitreous luster
- Transparency: Transparent to opaque
- Color: green
- Refractive index: 1.566~1.600
- Birefringence: 0.004~0.010
- Fluorescence: orange-red fluorescence in long and short wave
- Cleavage: Imperfect cleavage
- Characteristics: pleochroism, occasional cat eyes, rich inclusions
Commercial Value of Emerald
Emerald’s prominence comes from three main factors:
- The chromium-infused green can be either vibrant or soft, comparable to the finest “Old Mine” or “Yang Green” jadeite.
- High-clarity emeralds offer excellent transparency, surpassing jadeite in terms of faceting options. Lower-clarity emeralds are often cut as cabochons or carved into intricate shapes.
- Emerald’s worldwide recognition places it among the top-tier gems, equal in reputation to diamonds, rubies, and sapphires.
Color is the most crucial factor in determining the value of an emerald.
According to the Gemological Institute of America (GIA), emeralds are graded into three levels: commercial, medium-grade, and top-grade, based on color quality. The key distinctions in emerald color lie in the hue (purity of color), tone (balance of light and dark), and saturation (vividness of color). The most renowned Colombian emeralds are known for their deep, vibrant green or green-blue hues, symbolizing the finest quality.
One of the most distinctive features of emerald identification is its “low specific gravity.”
As part of the beryl family, emerald has a relatively low specific gravity and refractive index compared to other precious gemstones, which is a notable characteristic.
Additionally, there is an unwritten rule that emerald must contain chromium to be distinguished from ordinary green beryl. There was a famous lawsuit where the buyer argued that their emerald, though green, lacked “chromium ions,” meaning it was only green beryl. The buyer won the case, establishing that emerald must contain chromium to be considered different from green beryl.
Flawless emeralds are extremely rare. In fact, emeralds almost always contain some level of fractures and inclusions, with such a variety of internal features that researchers have dubbed them “gardens.”
While inclusions may decrease the value of an emerald, for gemologists, these inclusions provide invaluable insights. By studying them, it is possible to determine the gemstone’s origin and growth conditions.
Despite the impact that inclusions have on the appearance of emeralds, no other gemstone can rival the beauty of its vibrant green color.
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