Emeralds

Emeralds are part of the beryl family of gemstones, which also includes blue aquamarine and pink morganite. A green colour is caused by the presence of the trace elements chromium and vanadium, which absorb certain wavelengths of the visible light. In order for a green beryl to be called emerald, chromium must be present. 

For the formation of beryl, relatively large amounts of the rare element beryllium are required. These occur mainly in rocks of the continental crust. The colour-giving trace element chromium is typically found in completely different types of rock, usually in the oceanic crust and the earth’s mantle. Therefore, the formation of emeralds must occur primarily in zones where magmatic beryllium-containing rock comes into contact with magmatic chromium-containing rock - an extremely rare incidence. The fusion is only made possible by heat and pressure, therefore introducing stress during crystallisation that causes imperfections and fractures. 

Emeralds contain inclusions: foreign material, such as liquid, solid, or gas that is trapped within a gemstone. These are one of the most important microscopic characteristics of emeralds and they are a strong indication of natural origin. Rather than being seen as flaws, these fractures and inclusions are in their own right beautiful and they are part of the gemstone's unique character. Emerald lovers call these fascinating inclusions "Jardin" (from French: garden). They give each emerald a unique fingerprint and affect its "fire", the brilliance of the stone. The most common inclusions in beryl are hollow tubes and liquids in the form of healing cracks and two-phase inclusions. A characteristic inclusion in Colombian emeralds is a three-phase inclusion, containing a salt crystal, liquid and a gas bubble. While emeralds are relatively hard gemstones, the presence of inclusions makes them brittle and difficult to cut. The emerald cut - an octagonal step cut with bevelled edges – was developed to minimize the risk of damage the the gemstone's corners.

Commercially relevant emerald producing countries today are mainly Brazil, Colombia, and Zambia, with lesser production volumes emanating from Afghanistan, Ethiopia, and Pakistan. Colombian emeralds have formed in hydrothermal conditions, which makes them a rare exception! The Cordillera Oriental, where the emeralds are found, used to be the bottom of a seabed that was folded upwards by the collision of continental plates. Emeralds formed in the resulting hydrothermal process between 30 - 65 million years ago and then crystallised relatively undisturbed in veins and cavities. As a result, the crystals can be relatively big, they are homogenous and have fewer fissures and inclusions than - for example - Brazilian emeralds. Colombian emeralds are also naturally clearer and contain mainly chromium, moderate levels of vanadium and almost no iron, giving them a vibrant, beautiful, green colour tone with a hint of blue - which is so desirable. Nature’s perfection. Hence, the magic of Colombian emeralds. 

Read more in one of our reports. 

For over 5000 years, emeralds have been one of the most desirable and highly valued gemstones. Together with rubies and sapphires, emeralds are among the most sought after fine gemstones. The oldest known mines date from Egypt around 3500 BC, and Egyptians, Greeks and Romans viewed emeralds as a rare and precious gemstone for kings and emperors. Several writers of ancient times mention emeralds and their special status. 

The emerald is the birthstone of May and symbolises good fortune, hope and health. In various cultures, emeralds are associated with fertility and healing. In the Middle Ages, people held the belief that emeralds could be used to treat certain illnesses.

Long before the Spanish arrived in South America, pre-Colombian civilisations like the Muzo, the Muisca and the Chibcha already held emeralds in high regards and used them in ceremonial objects and jewellery. The mines of Muzo and Chivor have been in operation for over 1,000 years, and this still is where some of the finest known emeralds originate. Muzo ranks among the most famous denominations of origin, alongside sapphires from Cashmere, the legendary ruby mines of Mogok, or diamonds from Golconda.

When the Conquistadores brought Colombian emeralds back to Europe, people were astonished to see such fine qualities of emeralds, never seen before. From Spain, Colombian emeralds then found their way to places as far away as India and Persia.

Some emeralds have gained fame for their size, others for their historic importance or their famous owners. Pictured above is the famous "Crown of the Andes", now part of the collection of the Metropolitan Museum of Art in New York. It feaures a 45ct emerald that supposedly belonged to the Inca emperor Atahualpa. 

"The 'Crown of the Andes' is considered one of the most important surviving examples of goldsmith work from colonial Spanish America..."

The fascinating legend of Fura and Tena tells about the origins of mankind and is an important part of the cultural heritage of the emerald mining region. Fura (840m) and Tena (500m) are the names given to two impressive, characteristic mountain crags dominate the valleys of the Rio Minero beneath. These two peaks had religious importance for the nearby indigenous tribes, considered the seat of their gods and an altar for religious sacrifices. Now they have become emblematic for the emeralds-producing region near Muzo. They are covered in pristine, rich, green forests and shelter an incredible biodiversity with more than 3000 varieties of butterflies. 

As the legend goes, the creator god, called Are, after creating the land with all its valleys and mountains and rivers, noticed that something was missing from his creation. He picked up some reeds by the river, and from the smaller one he formed the figure of a beautiful young woman, Fura, and from the bigger one he formed a young man, Tena. Then he breathed life into them - the first human beings. Then he created sun, moon and the stars. Are gave Fura and Tena the gift of eternal youth and he taught them all the skills imaginable. He told them that their life would be happy, there would be no pain, nor illness or death and he gave them rules to live by, most importantly, the commitment of eternal fidelity to each other. Under no circumstance should this unique bond of exclusive fidelity be broken ...or they would be punished with aging, unhappiness and death. So the couple lived for a very long time on this magnificent land in total happiness. Years and centuries went by, generation after generation was born and they populated the world and formed the Muzo people.

But one fateful day, a beautiful young man appeared, looking for a miraculous flower that could relieve all pain, cure illness, and that gave eternal youth. His name was Zarbi. He climbed all mountains, crossed all rivers and searched all forests without success. Eventually, he asked Fura to help him. The compassionate Fura took pity and agreed to help, so they went to search for the flower in the forest together. As Zarbi and Fura were together, their desires grew stronger and took over, leading to Fura's act of infidelity towards Tena. 

She immediately began to age - the announcement of certain death. Realizing her error, her bad conscience and the memory of Are's words began to haunt her with guilt and she fell into a state of sadness and left Zarbi. When she returned to Tena, he immediately understood that the sacred law of unique and exclusive love had been violated. Every day, he could see Fura aging more and feelings of shame and revenge tormented his soul. He could no longer bear the pain and not wanting to be left to live alone, he stabbed himself in the heart. 

Fura, overcome with remorse and heartbroken herself, took the dieing Tena in her arms and broke down in tears. So immense was the pain and grief of Fura, she cried without consolation for many days that seemed like centuries, while holding Tena's lifeless body. Fura's screams of anguish perforated the silent jungle turning into into millions of multi-coloured butterflies that populate the region and her tears were transformed into the emeralds that today lie beneath the mountains. While Tena lay dieing, Are, overcome with rage, turned Zarbi into a big rock that would have to watch with bitterness the tears of his lover Fura. 

Seeing Fura's pain, Zarbi asked for forgiveness and pleaded with Are to have mercy. His wish was granted and Fura and Tena were turned into stone, separated for eternity by the Rio Minero beneath and reminding us of the tragic destiny of human life. The sad fate of Fura and Tena touched the heart of Are and he gave them a "permanent guard of storms, lightning and serpents".

It should only ever be the waters of the Rio Minero, that discover, clean and polish the Muzo's emeralds - the tears of unfaithful and repentant Fura.

The value of an emerald is, ultimately, established by supply & demand. The diamonds market is characterised by relative stability and a dominance of a number of big players who manage supply and invest into big marketing budgets to stabilise demand. In contrast, the coloured gemstone market is traditionally fragmented and the supply of emeralds depends on mining success, which can be unpredictable. The relative rarity of emeralds makes them one of the most expensive gemstones, achieving prices often in excess of those of diamonds. Diamonds are sorted and standardised, and thus almost have become commoditised, with transparent prices associated to each quality grade. In contrast, it is impossible to have normalised coloured gemstone qualities. Especially emeralds exhibit such a wide range of qualities, that minute details can lead to a wide divergence in pricing. 

In a given demand/supply situation, the value of an emerald is determined by the combination of relative beauty and rarity. For example: gem quality material makes up 1% of production of facetted Colombian emeralds, not even counting the material not worth polishing. Emeralds of gem quality are believed to be 1 in 1000 - and extremely expensive!

Some objective criteria for judging beauty and rarity of facetted coloured gemstones can be found in the 5Cs: 

- Colour - Clarity - Cut - Carat Weight - Country of Origin

1. Colour is by far the most important factor affecting emerald quality and value. Colombian emeralds are deemed to be the most desirable due to their colour tone, a soft deep pure green with a slight blue hue. 

The Gemological Institute of America (GIA) has developed a helpful grading system for the assessment of colour, based on three sub-components: Hue (shade of colour), Saturation (the degree of intensity of the colour) and Tone (the lightness or darkness of the colour).

In emeralds, hues could be variations of a yellowish green or a blueish green. Blueish greens are generally deemed more desirable. Saturation has a big effect on the appearance of an emerald and its price. The stronger the colour, the rarer and more valuable the emerald will be. Within rough emeralds, one can often find areas of concentrated or uneven colouring, whereby the green colour is more intense on the outside of a rough crystal and less intense on the inside, or the rough may be only partially coloured. Colour zoning (distinct dark and light areas within a gemstone, or different hues within a gemstone) will significantly diminish the value of a facetted emerald. Tone is alluded to as the shade, or tint of a shading. Quality emeralds tend to have a medium tone. 

2. Clarity refers to the transparency of the emerald, which depends on the number of inclusions and their position within the gemstone. As long as there are not too many inclusions, these not necessarily deemed to be defects. An abundance of inclusions will negatively impact stability of the emerald and obstruct light from passing through the gemstone. The absence of inclusions is  rare, hence making such stones very desirable and extremely valuable. Emeralds with prominent and visible inclusions have a much reduced value. 

Surface-reaching fractures are the means by which emeralds are oil-treated. The degree of oiling can be obtained in a laboratory report. Comparing two eye-clean emeralds of the same colour and beauty, the stone with less treatment will be more valuable, and the price increases exponentially the less treatment is present. A normal emerald would exhibit evidence of 'moderate' clarity enhancement. Finer qualities have minor, or insignificant classifications. “No oil”- emeralds are the finest quality and command much higher prices, provided colour and clarity are right. Significantly enhanced emeralds may appear of deceptively high quality, but they trade at a discount as the oiling is likely to have improved their appearance considerably. Surface-reaching fractures on the exposed table of the emerald are value-reducing, because any deterioration of the filler would be visible to the naked eye!

3. Cut refers to the accuracy of the angles, proportions, symmetry and polish of the emerald. Facets give gemstones a three-dimensional effect, resulting in darker and lighter tones and brilliance, from refraction and reflection of light from the facets. A careless cut with mistakes and bad finish can negatively impact the price of the emerald. However, a bad cut can potentially be corrected with relatively little effort, and its impact on valuation is therefore by far not as important as that of Colour and Clarity. 

Emerald is a relatively hard, but brittle gemstone, which makes it a difficult gemstone to cut, in particular due to the presence of inclusions. The emerald cut is a cut that is designed to minimise the risk of damage to the facetted stone. The cutter will try to cut the rough in such a way to bring out the best in the emerald, not too dark, not too light, hiding inclusions and colour zoning, while minimising the weight loss (up to 70% of the rough gemstone are lost in cutting). The cut should be proportional and symmetric, without any facet misalignment. The polishing should display exceptional brilliance and luster, there should not be any polishing marks. As few surface-reaching fissures as possible should be on the table of the gemstone.

Sometimes, identical-looking emeralds can have different prices due to "cutting accidents" or differently priced rough material. 

4. Carat Weight: It is unusual to find large emerald crystals, big enough to yield large facetted emeralds, hence the relative rarity of finding a 15 carat emerald versus a 1 carat emerald makes its price increase exponentially. There is no exact conversion table, as prices vary according to demand and supply and also differ for the different qualities of emeralds. Per carat prices for >10ct emeralds could be 10x-25x the price of a 1ct emerald of equivalent quality. 

Note: Larger gemstones will appear darker or exhibit a deeper tone of green than a smaller stone of the same colour. 

A fifth C, country of origin, gradually became more important in the trade over time - in some instances more important than quality. Geographic origin may also be an indicator of the rarity and beauty of a gemstone. Some deposits only lasted for a short term, so the supply is limited. Colombian emeralds are associated with the unique history of the country and its legendary mines. Beyond beauty, buyers are prepared to pay a premium for being a part of that story. Relatively "new" emeralds from Zambia do not have the history associated with them and are mined on an industrial scale that leaves little room for romanticism. The cost of extraction also differs: environmentally conscious tunnel mining in Colombia is much more expensive than the open pit mining in Zambia, thereby increasing the cost of rough emeralds. 

The emerald deposits in Colombia are located in the Cordillera Oriental. Two main areas can be distinguished, due to the different properties of gems found there. 

The mining region of Muzo is situated in the Western emerald belt, to the North-West of Bogota. This is the largest emerald district in Colombia, and it is the most well-known emerald mining region in the world. Muzo is not one single mine. It rather refers to dozens of mining operations in the vicinity of the town of Muzo. The region comprises the mines of Cosquez, Cunas, El Chulo, La Pita, Peñas Blancas, Puerto Arturo, Santa Barbara, Tequendama, Yacopí and others. Already mined during pre-hispanic times, they provide sometimes very fine qualities of emeralds of evenly distributed deep green colour.

The second main area is the Eastern belt, which comprises the region of Chivor, to the North-East of Bogota. Chivor, formerly Somondoco, is the oldest mine in Colombia. The mines of Buenavista, Gachalá and Macanal are found in the same region. Compared to Muzo emeralds, the majority of Chivor stones tend to have a less intense green colour, but they have fewer inclusions. The relative lack of inclusions makes Chivor emeralds more stable than Muzo emeralds. It also results in a high clarity and brilliance. The colour typically exhibits a marked blueish hue, an electric colour that is reminiscent of Paraíba tourmalines or mint tourmalines. 

Emerald mining in Colombia is challenging: The emeralds sit in small veins that are difficult to track and follow, due to tectonic ruptures and fault lines. Concentration and quality of emeralds in these veins vary significantly. Mining production in any of the Colombian mines is sporadic, due to the unpredictable nature of the emerald deposits. While modern geological prospecting can be helpful, the business still depends to a good degree on luck. Mining in Colombia is largely artisanal and, since open pit mining is banned, miners dig tunnels into the mountain and try to follow the veins and fault lines. Sometimes, a mining operation may go for months without finding significant emerald pockets, which is why all mining operations also engage in buying and selling of emeralds from third parties. 

Emerald mining activity is regulated by the government, which awards licenses through the National Mining Agency. Business models between the registered mines differ: The big mines of Puerto Arturo and Cosquez are leased out for a fixed period. Many mines are on private land/property, but also require a license. The traditional model has been to have one major license taker who sub-license concessions, or a mine could be run by a cooperative. The size of operations varies considerably, from just a few people to thousands of employees.

'Guaqueros' is the name given to informal miners. They often come from poor families from the region or have come to the area in the hope of finding fortunes. Guaqueros sift through rock discarded from the mines, dig up the riverbed or dig illegally on public land. While an informal activity, it provides a living to whole communities. When a guaquero finds an emerald, he can either try to pay a cutter to re-work and increase the value of the gemstone, or he could sell it to a merchant who trades the gems directly on the streets of Bogota. It was tradition for the mines to offload the rubble extracted from the mines into the riverbed, for the Guaqueros to wash. When the government put an end to this practice, hundreds of families lost a source of income. 

Responsible mining is of high importance in today’s society and buyers want to know that their gemstones come from responsible sources. Colombia is not a perfect place, but it should be noted that all people working in the mines do so voluntarily. Plenty have in the past made a fortune doing so. There is no child labour in Colombian mines. There are workplace safety regulations and people handling explosives must have completed a safety course. Companies are required to pay a minimum wage. Contrary to gold mining, emerald mining does not involve harmful chemicals and there is no contamination of soil and water through toxins. Open pit mining, which has an adverse effect on the landscape, has been banned in Colombia for considerable time. In order to obtain a mining license, operators have to submit an environmental assessment, therefore ensuring that standards are met and no harm is done to one of the most biodiverse countries on earth. The new arrival of foreign multi-national mining companies and the formalisation of mining by the government have brought positive developments, but they have also led to a reduction in activity and have driven many into unemployment and into the slums of the big cities. We try to support smaller mines and independent artisanal miners where possible. Small scale mining provides a living to thousands who would otherwise not have a source of income.

If this is a topic of concern or particular interest to you, please refer to our detailed report on EMERALD TREATMENTS in the Download Section below.

Nearly all emeralds are treated to improve their appearance. “Oiling”, fracture-filling or clarity enhancement are the terms used to describe this process. This practice has been common since the times of the ancient Egyptians and it is widely accepted. An emerald that exhibits no evidence of clarity enhancement is also commonly called a “no-oil emerald”. 

Surface reaching fractures are filled with a colourless liquid that enables light to pass through the emerald unhindered, thereby improving its appearance. In ancient times, cedar wood oil and other oils were used for this purpose, but today a wide range of substances are actually employed, depending on the origin of the emerald. Artificial resins have become the common filler substances for the clarity treatment of emeralds today. 

Heavily treated gemstones may appear of deceptively high quality, which is why it is recommended to have valuable emeralds certified by a reputable laboratory. A laboratory report will identify the gemstone as a “natural emerald” (as opposed to a synthetic or a composite emerald), it will state whether there is evidence of clarity enhancement and to which degree the emerald has been improved by this treatment. This will tell the buyer, how much the emerald’s appearance could worsen with time, if the filler were to deteriorate. Enhancement levels are classified as: None (No-oil), Insignificant, Minor, Moderate, Significant and Prominent. Since all emeralds have inclusions and fractures - and all emeralds are usually clarity-enhanced - it is accepted that an average typical emerald could be expected to display evidence of “moderate” clarity enhancement. 

The value equation also includes colour, weight, origin and the presence of other inclusions, so the degree of treatment does not by itself equate to an emerald’s value. “Significant enhancement” does not necessarily mean low value. Likewise, “minor enhancement” or “no evidence of enhancement” does not necessarily mean high value, if the stone has a weak colour or many internal inclusions that are not surface-reaching. The value of a low-quality emerald will not be improved by a report that says it has only minor enhancement. 

The first desirable property of a clarity enhancement is that its refractive index is close to that of the emerald. All clarity enhancements deteriorate over time. Therefore, durability is the second important factor in judging a clarity enhancement. Thirdly, the filling liquid should be clear and colourless. 

There exists a lot of misinformation, confusion and apprehension about emerald treatments. The type of filler is a hotly contested subject of discussion and part-truths are happily spread, even by well known influencers, suppliers with an agenda and misinformed jewelers. 

There are three types of possible treatments

1. Oils (natural or synthetic)

2. Liquid Resins/Pre-Polymers (natural or synthetic)
3. Manufactured Polymers 

They differ in that the first two are liquid, and the last is a hard filler. There is little difference between oils and resins! Through additional treatment and processing (turning them into polymers), resins can be hardened or surface-hardened. It is prudent to avoid these hard/hardened fillers. 

At Monteverde Emeralds we only work with fine quality emeralds, from no-oil up to moderate clarity enhancement. Since we perform the oiling ourselves, we are able to always fully disclose the type of treatment.

Emeralds are less complicated as it is often thought: oiling is the only possible treatment. Heat and radiation do not change the emerald's colour and as a result, these techniques are not employed. Emeralds cannot be filled with glass, because the heat would make the gemstone break in the process. 

Oiling does not alter the natural gemstone itself: the emerald can be cleaned, which will completely remove the clarity enhancement liquid. 

Emeralds are relatively hard gemstones, but due to the presence of inclusions and fissures, they have weak points and can be brittle. To avoid damage, you should treat them with love and care. With the right care, your emerald jewellery will last a lifetime and much longer!

Common sense indicates it is not a good idea to wear an emerald ring - or any gemstone ring for that matter - during gardening, dish-washing or any intense physical activity. 

Emeralds are best cleaned with a water-dampened, soft cloth or with a dust-free, clean wiping cloth. This will normally remove fingerprints and other minor soiling. Do not use soap or detergents. It is best to store your emerald jewellery in a cool place. This will make the clarity enhancement (if present) last longer. 

If you are thoroughly cleaning a piece of jewellery, the emerald should be removed from its setting and re-set once you have finished cleaning the piece of jewellery. If it is not practical or possible to have the gemstone removed, cover and protect the emerald from the work that you are performing. Do not subject the emerald to heat! Do not brush the gemstone, as this may cause damage to the gemstone or remove the clarity enhancement from surface reaching fractures. 

Never clean emeralds with acetone, alcohol, steam, soap, or ultrasound! The former may remove or at least impact the clarity enhancement while the latter may break the gemstone. 

We provide re-oiling of lose emeralds to our clients. Oiling is a process that can very rarely lead to damage, for example when an emerald with a hard filler is being re-oiled without prior cleaning. Since we cannot vouch for the integrity of other providers' emeralds and their fillers, we only re-treat emeralds sold through ourselves.