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An in-depth Guide to Buying an Emerald Engagement Ring

By Flawless Fine Jewellery

This buyers guide is designed to help you buy the perfect emerald engagement ring, with 100% certainty that you have bought the right stone!

A brief history of Emeralds

Since antiquity, emeralds have been coveted for their intense, vibrant, green colour. Cleopatra famously had her own mines dedicated purely to the excavation of the gemstone. The mines (sadly no longer in use) were operated by hundreds of men whose existence was solely focused on procuring her green gems.

Even today, emeralds are still held in the same high regard. Recent emerald connoisseurs include the likes of Elizabeth Taylor and John Rockefeller jr; both of whom’s emerald jewellery has broken world records when sold at auction with the latter and formers jewellery selling for $5,511,500 and $24,799,000, respectively.

emerald engagement ring

In stark contrast to the past when emeralds were predominantly mined in Egypt, you’ll find that over 60% of the world’s emeralds come from Colombia with the majority of these stones being split among 3 massive mines: Muzo, Coscuez and Chivor located within the Andes mountain range which runs northeast-southwest through the country.

Recently emeralds are having a resurgence in popularity, with lots of american jewellers keeping a rich stock of columbian emeralds due to this fact. Alongside Colombian emeralds are Zambian emeralds, these are popular because they also sport the rich green colour and, in contrast to Colombian emeralds it is very easy to find two stones of matching quality.

When shopping for emeralds it is important to remember that location can drastically affect the price. For example, when a stone comes from Colombia in that desirable, green colour and quality, the price of that stone can be exponential compared to an equally beautiful stone from Zambia or Afghanistan; which have also been known to produce high quality emeralds (though afghan stones are less common these days).

Emerald Quality

This section is designed to educate you on what your criteria should be when choosing the perfect emerald.

Taking all of the previous information into account, when purchasing an emerald your priorities should be: colour, clarity, saturation, origin, treatment and certification, respectively.

Colour

Firstly colour plays a huge part with emeralds. All emeralds are dichroic (this means that the stone has 2 colours the primary green and a secondary blue or yellow, these secondary colours are also called hues), blue is generally considered to be the better colour because it is a darker tone which benefits the saturation (see Saturation section for more information) so when choosing to buy your emerald the most desirable colours range from a lovely bluish green to a pure vivid green with a very rich colour while featuring a medium to dark tone.

emerald engagement ring
emerald engagement ring

Clarity

in emeralds clarity is a key factor in terms of quality, the most coveted emeralds have a good amount of transparency. Clarity refers to the amount of inclusions and blemishes contained within a stone, all emeralds contain inclusions this is unavoidable due to how they form within the earth and finding an emerald with no inclusions is the first sign of a synthetic stone (all natural emeralds have inclusions, this is how they are distinguished from their synthetic counterparts).

The left emerald features beautiful colour and the expected amount of inclusions from a high quality stone.

The right emerald while having beautiful colour is however heavily included which greatly decreases the stones quality and thus the stones price.

Windows

While transparency is good sometimes you can find an emerald containing a window (which is when the colour in the centre of the stone lacks depth compared to the rest of the stone)which can make the stone less desirable and is a sign that the stone has been cut poorly making it too shallow.
On the left we have an example of a perfect quality emerald. On the right we have a very clear emerald containing a central window.

Saturation and Tone

In emeralds saturation of colour plays a big part in their quality (and worth) as a lighter colour stone which has a lower degree of saturation is normally less desirable than it’s more saturated counterpart, this owes to the fact that emeralds are more coveted and thus more expensive when they are that darker lime colour. Tone is the type of colour the emerald holds e.g a lighter colour or a darker colour. Tone helps to determine the saturation of the emerald, due to the secondary colour. For example a lighter tone means less saturation (this is more common in stones with a yellow secondary colour hence a blue secondary colour being preferred) and a darker tone means more saturation (more common in stones with a blue secondary colour). However your choice should be a stone that has a good mix of tone and saturation. Go for a stone that has a medium bluish tone while having that vivid lime green. (for example the stone seen below)

Origin

Your stones origin is important due to its geographical birthplace have a rather significant effect on the price of your stone, as well as stones from different regions having different elements present during their formation, which in turn lend themselves to changing the properties of the stones.

Colombia

Colombia is the most reputable source for emeralds, and its 3 mines have been running since the early 1500s when the Spanish came to South America, and began exporting the stones back to Europe and the Far East. Colombian emeralds are valued for their rich green saturation and medium bluish tone which combine together to create that vivid green colour that is so highly coveted in emeralds. Colombian emeralds are also known to contain a lot more inclusions that other locations due to their forming in sedimentary rock. They often contain a large amount of thin string-like inclusions called jardin (garden in french).

Emeralds from Colombia owe their higher price to their more prestigious reputation as well as the difficulty that comes with cutting the rough stones. This difficulty comes from how the colour of the emerald is distributed inside the rough, and the constant possibility that the cutter can take away all the colour with one wrong cut, due to the colouring agents being mainly situated around the stones exterior. This risk means that cutting colombian emeralds requires a higher degree of expertise thus incurring more costs and adding to the overalls stones price at sale.
this stone is a premium example of a Colombian emerald in terms of quality.(this stone also features a Jardin).

Zambia

So we have already established that Colombia is the “gold standard” for high quality emeralds, but up there with Colombian emeralds is Zambia, and while the history behind Zambian emeralds is young in comparison to Colombia, Zambia is slowly becoming a reputable source of beautiful emeralds!

Mining for Zambian emeralds was first initiated in 1976 at the Kagem mine. However the mine did not start producing high quality emeralds consistently until 1984. In 2005 Gemfields (the leading excavator of Zambian emeralds today) began mining in and around Kagem. Then in 2007 Gemfields created a partnership with the Zambian government establishing a 75/25 split ownership of the Kagem mine. I think it is fair to say that Gemfields are responsible for making Zambia the lead provider of emeralds worldwide (20% of emeralds in the world come from Kagem) and in 2009 excavated a shocking 27.6 million carats of rough emeralds!

Zambian emeralds while held in a lower regard to Colombian(due to colombia having a longer history and more ingrained popularity in the gemstone market) are still very beautiful stones holding a very deep vivid green colour, and contain less inclusions that Colombian stones. Zambian emeralds are also harder than colombian (zambian emeralds can range from 7.5 to 8 on the mohs scale while colombian stones stay at 7), which enables them to be cut with less fear of ruining the stone.

In terms of quality Zambian emeralds are known to hold a slightly darker bluish tone than their Colombian counterparts, due to the presence of iron and vanadium during formation. This darker tone means that lower quality Zambian emeralds are quite common due to said tone negatively impacting the saturation of the stones. (see saturation and tone chart featured above)

This zambian emerald is a prime example of the darker blue tone this is common in zambian stones.

Treatment

As emeralds are very soft stones often they are found to contain striations or fractures within the stone. To combat this most emeralds are treated with oil which then fills these cracks improving the emeralds clarity. All emeralds are graded on their level of treatment and all emeralds are placed in type 3 of GIA’S categories for coloured gemstones. Because of this oil or resins are used to increase their standing on the type scale.

When choosing an emerald it is normally best to choose a stone with minimal treatment, because a traditional treatment like cedarwood oil will dry out over time, making the inclusions more prevalent. So if a stone has been heavily oiled, when it dries out it will reveal a lot of inclusions ruining the stone.

Type 1 gemstones: These are typically inclusion free, or almost inclusion free.
Type 2 gemstones: These gemstones are usually included.

Type 3 gemstones: These are almost always included.

Natural AAA: This is the highest quality. It represents are the top 10% of gemstones. Natural AAA emeralds are rich green, moderately to slightly included, and they exhibit very high brilliance.

Natural AA: This is the second-best category for gemstones. Natural AA gemstones account for 20-30% of all gemstones. Emeralds in this category are medium green and may include moderate inclusions.

Natural A: This category accounts for 50 to 75% of all gemstones. Natural A emeralds are dark green, heavily included, and opaque. They are still good, but they are considered to be of a lower quality compared to the two categories above.

Apart from Natural AAA, AA, and A, there’s also a category called Heirloom/Rare Emerald. This is the highest quality, even better than AAA. They are extremely rare and expensive.- taken from https://www.withclarity.com/education/gemstone-education/emerald-gemstone/emerald-grading

Gemological reports usually indicate the level of clarity enhancement for emerald, ranging from None to Insignificant, Minor, Moderate and Significant.- taken from https://www.ajsgem.com/articles/emerald-enhancements-and-treatments.html

Many different oils and resins are used when treating emeralds, but the most common is cedarwood oil which is used for due to it’s colourless nature and refracting light at a similar scale to emeralds. In the 1980’s Brazil began using a synthetic resin called opticon which was quickly acquired by colombia, and became popular because of its better stability (does not dry out like oil meaning one time usage), and have a refractive index which was almost identical to emerald (a refractive index is a dimensionless number that describes how fast light travels through the material). the use of this resin sent shockwaves the jewellery market because many emeralds were being distributed with this treatment but were being labelled as no treatment used, which caused buyers to become nervous about buying stones from Colombia.

Certification

The last detail to cover about emeralds is certification. Unlike with diamonds GIA is not the best choice for coloured stone certificates, instead the 2 most reputable and trusted certifiers of coloured stones are Gubelin and SSEF. Both of these laboratories take the certification of stones very seriously and thoroughly: inspecting, analysing and grading stones with the utmost care and precision. While both certifiers will inform you to what degree your stone has been treated, neither can inform you what treatment agent has been used as “They refuse to specify the exact type of treatment agent not because it is impossible to identify it, but due to the fact that these laboratories will only state in writing what they can say with 100% accuracy. SSEF is the only Swiss lab that gives any indication of the treatment type, classifying it as either ‘traditional’ or ‘modern’,” ( quote by george smith co-founder of International Emerald Exchange). These classifications of modern and traditional are used to reference whether the stone has been treated with a natural oil (e.g cedarwood oil) or a synthetic resin (like opticon).

emerald engagement ring

To conclude this article i have decided to round out all the key points of each section to make it easier for you to remember what your criteria should be.  Since saturation and tone affect colour they will all be grouped as one area. This is the same for clarity and treatment.

  • Colour: the perfect colour is around the strong lime green area, without any windows within the stone and not having too dark of a secondary tone (preferably blue). The picture below is an example of a stone with these criteria.
  • Clarity: all emeralds have inclusions so you should not go out looking for a perfectly clear stone, instead you should look for a stone with less noticeable inclusions and minimal treatment so that you know the stone will hold its beauty.
  • Origin: the emeralds origin is important, because Colombian emeralds contain different minerals to Zambian emeralds, which means they have different attributes. If you want a lighter green emerald with a light blue tone, Colombia would be the better choice but the price would be higher. Zambian emeralds are the better choice for darker more saturated colour, due to the presence of iron making them have a slightly grey tone and the price will be lower.
  • Certification: when buying a high quality emerald, it is always important to make sure the stone is certified, especially if the seller said that the stone is from Colombia as the certificate will be able to verify its origin, as well as if the stone has been treated and to what extent. Certifications are important because they allow you to be 100% certain you are receiving what you initially paid for.