Learning Library

Emerald Gemstone

Re-discover the most famous gemstone of all.



To own an Emerald is to own a piece of history, a piece of nature and a work of art. Each one is truly individual. With its array of inclusions and clouds, the gem is not famed for its crystal clarity, but is steeped in so much history that we automatically ignore the gem’s imperfections when we study a piece and accept that these impurities are simply “the fingerprints of Mother Nature”.

The gem world is a strange place to reside if you are looking for logic and reason: with so many other green gems available with almost perfect clarity and in some cases greater rarity, it is not at all logical that Emerald is still viewed as the king of the green gems. Its price is often greater than Diamonds of a similar carat weight. So when you own an Emerald, treat it as your own work of art, get to know its lines, its patches, its identity and don’t let anyone tell you it is anything other than gorgeous - after all beauty is in the eye of the beholder.

Some Emeralds have an almost velvety appearance, and are one of only a few gems where inclusions are not only tolerated, but considered to be part of the gem’s character. As a general rule, a vivid Emerald, full of inclusions, will normally demand a higher price than a flawless one paler in colour.

Its name is derived from the Greek word “smaragdos”, a label given to a number of gems with the colour green in common. Representative of the ‘colour of spring’ Emeralds are said to signify hope, new growth and eternal life.

As with Peridot and Alexandrite, Emerald is only available in one colour: green. This wonderful creation of nature is a variety of the Beryl family (a mineral group that includes Aquamarine, Morganite and Heliodor) and receives its colouring from traces of chromium and vanadium within its crystal structure.

Mined over 4000 years ago in Egypt, during the reign of Pharaoh Sesostris III, this precious stone has been held in high regard since antiquity. Many virtues are ascribed to this jewel - said to promote constancy of mind, to quicken intelligence, and drive away evil spirits. Emerald is believed to bring wisdom, true friendship and foresight in to the future.  

Pliny the Elder, first century AD author of the great “Natural History”, wrote; “...no colour is more delightful in appearance. For although we enjoy looking at plants and leaves, we regard Emeralds with all the more pleasure because compared with them there is nothing that is more intensely green”. Although not a believer in myths, Pliny did go on to say: “And after straining our eyes by looking at another object, we can restore our vision to normal by gazing at an Emerald”. He also correctly identified Emeralds as part of the Beryl family.

The Greeks, who were working at the mines of Alexander the Great, were said to have yielded their gems to the Egyptian Queen, who was notorious for her love of Emeralds. In 1817, “Cleopatra’s mines” - once thought to be myths - were discovered on the coast of the Red Sea, therefore validating their existence.
Shah Jahan, the architect of the Taj Mahal, wore them as talismans inscribed with sacred text. His ‘Mongul Emerald’ is noted as one of the two most famous Emeralds, dating back to 1695. It is an impressive 10cm tall and weighs 217ct; in September 2001 it sold for $2.2 million dollars at auction to an anonymous bidder. The second most renowned Emerald is the 632ct ‘Patricia Emerald’ and is on display in the National History museum in New York.

Emerald was revered as a holy gemstone by the Incas and Aztecs and was associated with Venus, goddess of love and beauty, by the Romans. Emeralds are associated with the astrological sign of Taurus. It is the birthstone for May and the anniversary gemstone for the 20th, 35th and 55th year of marriage.

Most Emeralds on the market are treated at the time of cutting with wax, oils or resins. Unlike nearly all other gemstones, most treatments applied to Emeralds are not permanent and to maintain the gem’s unrivalled beauty, need re-applying every 5 to 10 years. Because of their brittle crystal structure and normal mass of inclusions, cutting the gem is a real challenge. Very few gem cutters will even attempt to cut larger Emeralds, and the likes of Tel Aviv in Israel and Jaipur in India have produced many lapidarists who specialise in applying the Emerald Cut.

On a recent visit to one of my licensed workshops in Jaipur, I was fascinated to watch an Emerald cutter slowly shape a 3ct Emerald. Rather than the cutting wheel so often used in Thailand where the craftsman spins the wheel with his feet, Jaipur craftsmen attach a rod-cum-bow to the wheel. It must be 4 to 5 feet in length and as they slowly pull it backwards and forwards in a very serene manner, the cutting wheel begins to spin. Then, with a skill passed on from many generations, they delicately cut and grind the Emerald on the hand-driven grinding wheel.

Emeralds displaying bluish overtones are sourced from Colombia; these are highly coveted and considered by connoisseurs to be some of the world’s finest. Unfortunately, as I write this piece, these Emeralds are becoming increasingly rarer as mine owners are having to dig deeper and deeper - and with very little success.  Other sources of Emeralds include Brazil, Pakistan, Siberia, Zambia, and Zimbabwe.

When judging an Emerald its diaphaneity (transparency) is far more important than its clarity. Of course, if there are both a mass of inclusions and low diaphaneity then the gem is less desirable. But if it has a good degree of transparency, a deepish tone and an internal glow, then it is important to develop a far higher than normal tolerance of inclusions than you might otherwise have had.

Emeralds can vary considerably in their tone: some from areas such as Bahia in Brazil can be as low as 50% in some instances; some of the finest Emeralds I have seen tend to have a tone of around 70 to 75%.

For Emeralds from Brazil and Colombia, if they are over one carat in size it’s safe to assume that the gem has undergone treatment. Historically the treatments were waxes and oils that were added to increase the Emerald’s brilliance by filling its fissures and cracks. Today these non-permanent treatments have been in the main replaced by modern polymers that feature a very similar refractive index to the Emerald. These treatments are so good (especially the polymer supplied under the Opticon brand) that most gem laboratories are unable to spot them, so once again, unless your gem is supplied certified, it’s best to assume treatments have been applied.

For Emeralds from Zambia, most of the pieces I have evaluated and certainly all of those I have bought direct from mines in the Copper belt in the North of the country are untreated, other than the fact they are soaked in Johnson’s Baby Oil! The reason why this brand is used is that it has an identical refractive index to Emerald, therefore it maximises the gem’s brilliance. Best of all, it’s a treatment that does not need to be carried out by an expert. If one day your Zambian Emerald is looking a bit tired and lifeless, pop an egg cup full of Johnson’s Baby Oil into your microwave for 20 seconds or so, until it’s lukewarm, and once you are happy with the temperature pop in your Emerald ring and leave it on the side to soak overnight. It’s that simple.

Most people prefer the hue of their Emerald to be a pure green; most however have a secondary colour of either blue or yellow and occasionally both can be witnessed. Many a gem expert will tell you that the most valuable Emeralds must not feature any blue or yellow secondary colours, however both yellowish or bluish undertones have their advantages. Firstly, if an Emerald has a slightly yellowish tone in natural daylight (candescent light) it should look balanced under indoor or candle light. If on the other hand an Emerald has around 10 to 15% blue within its body colour, then it often makes the Emerald appear warmer and livelier.

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A Zambian Emerald set into a Lorique design

 

Brazilian Emerald