Guide to emeralds

What they symbolise

“Nothing greens greener.” This is how Roman naturalist Pliny the Elder chose to describe emeralds in his encyclopedia, Natural History, written in the first century AD. He was right: the intense green of emeralds is rarely matched, and it’s what has made the stone widely popular throughout the centuries.

Emeralds possess strong symbolic power, as they are thought to bring the wearer peace, hope and the prospect of renewal. For millennia, members of the elite have worn emeralds to achieve greater wisdom and protect themselves from disease. It is said Cleopatra was particularly fond of this precious gem as a royal adornment.

Emeralds are the birthstone for May and are given to celebrate 20th and 35th wedding anniversaries.

Timeless designs

Many famous creations feature emeralds of exquisite quality and finish, but perhaps the most sublime example of early jewellery design is the 16th-century Crown of the Andes. It features 450 emeralds, including an impressive 24-carat pure green gem that is said to have belonged to the last Inca emperor.

Among more recent examples, we find Elizabeth Taylor’s famous Bulgari jewellery collection, which features a 7.4-carat emerald ring, matched with a superb necklace and earrings set with Colombian emeralds and diamonds.

What to remember

Cost and carat
The final price of your emerald will be determined by many factors, including colour, carat, clarity, cut, treatment and origin. A right combination of these will ensure your gem’s long-term value remains steady and perhaps even increases over time.

Large emeralds are extremely rare, and so carat weight exponentially increases the value of your gem The price of a 10-carat emerald is usually 50 times that of a one-carat stone.

Colour intensity
The colour of an emerald is by far the most important aspect to consider when making a purchase, as this will have a significant impact on the stone’s value.

Unlike diamonds, there is no internationally accepted colour grading system for emeralds. Similar to other gemstone certifying bodies, and for greater accuracy, 77 Diamonds has adopted five levels of colour intensity that range from Deep to Light. The most sought after colour intensity is Vivid, as it holds the finest combination of tone and saturation.

We also classify emeralds in three different shades: pure, bluish and yellowish green. The intense saturation of pure green emeralds make them significantly more expensive. If your emerald has strong yellow or blue overtones, this will affect long-term value.

Clarity
The interior inclusions of emeralds are known as the ‘jardin’ (‘garden’ in French). Inclusions are greatly appreciated, as they enhance the beauty of an emerald by diffusing colour throughout the stone. There are three levels of clarity:

• “Eye Clean” (EC1 – EC2) indicates that inclusions are invisible to the unaided eye. Eye clean emeralds will be more valuable due to their scarcity.
• “Visible inclusions” (VI1 – VI2) indicates that inclusions are only slightly visible to the unaided eye.
• “Included” (I1 – I2) indicates that inclusions are obvious to the unaided eye.

Cut and shape
Emeralds are mostly step cut into an octagonal shape. This serves to intensify the gem’s fire while also strengthening its structure.

Emeralds can be prone to wear after years of continued use, and the long octagon helps to further its durability. Throughout the years, this shape has become synonymous with the unique look of emeralds, so much so that it is now referred to as the ‘emerald cut’.

Oval or pear shaped emeralds can also be found on the market. Keep in mind, the quality of the cut will also determine the final price of your emerald.

Treatment
Only the finest and rarest emeralds are unearthed in a perfect state without any need for further treatment, making them significantly more valuable.

Treated emeralds are therefore common and, for the most part, well accepted by the trade. To enhance clarity, emeralds often undergo an oil treatment (O). In a vacuum, oil is introduced into the stone’s fissures, erasing the most evident inclusions. This treatment is temporarily stable and can be repeated after several years.

Other methods include using artificial resin (R) to enhance clarity and stabilise the stone. This method is not well accepted by the trade as it is usually applied to low-quality gemstones.

Finally, oil and artificial resin (O+R) can also be combined as a treatment. In all three categories, there are distinct levels of treatment that range from minor to significant.

The type of enhancement used will affect the final price of your emerald. As an example, a one-carat emerald moderately treated with oil is around four times more expensive than a similar-sized gem treated with resin.

Origin
Although some emeralds may look similar, their prices will differ due to origin. Colombia produces the finest emeralds in the world and has an established history of mining. The country’s most famous emerald mine, Muzo, is well-known for producing stones of exceptional quality. Colombia was infamous in the past for its ‘green wars’, during which the emerald industry was blighted by unethical practices. This is thankfully no longer the case today, as mining conditions are both sustainable and in line with accepted standards.

The second finest country of origin is considered to be either Zambia or Ethiopia, followed closely by Brazil and Afghanistan. Finally, emeralds from Pakistan and Madagascar are the least valuable in terms of origin.