The internal display of inclusions and finger prints within an Emerald are created by the fusion of their growing environment (pressure, temperature) and the cocktail of chemical elements presented during their incubation. Like all long-lasting intimate relationships, the creation of a wonderful Emerald requires the correct environment and a precise chemical reaction, but Emerald also needs the added element of prolonged periods of sustained pressure. But just as no two relationships are identical, no two Emerald deposits are quite the same.
The vast majority of Emeralds you will see for sale today are uncovered in Brazil, Colombia or Zambia: I tend to refer to these as primary sources. However, these are not the only three countries to extract this historical and mystical treasure gifted to us by nature. The remaining locales I split into two groups: those that I know I can get hold of if I make enough phone calls and speak to enough traders (I call these secondary sources), and those where Emeralds have been known to be discovered but are only seen in the industry sporadically. Secondary sources for Emeralds include: Afghanistan, China, Pakistan and Zimbabwe (Sandawana). Other countries who have been known to unearth Emeralds, but not yet in sufficient quantities to open commercial mines, are: Nigeria, Russia (Siberia), Tanzania and the U.S.A.
Before we look at the typical differences of Emeralds found in different locations, let me override all of my observations with a quote from the most famous gemmologist of all time: George Kunz (I have had to paraphrase this because I cannot remember where I read it), “you are as likely to find a top class gem from an area not known for yielding great gemstones, as you are a low grade one from a location where the world’s finest are also mined”. This echoes what I experienced in a Zambian Emerald mine where in one square metre of host rock, we uncovered a few pieces of very high grade, fine clarity, intensely green pieces along with a piece that was dull, cloudy and which had a less attractive, yellowish green hue. So the following guidelines are simply what I regard as the typical qualities you might see, but in our world, a world of evaluating treasures provided to us by Mother Nature, there are no solid rules.
If you are a wine connoisseur there is a very good parallel to this. A certain grape variety has its own distinct taste, but this varies from location to location. The different flavours in wine are as a result of the local growing conditions, which the French poetically calls ‘terroir’. However, even in the same vineyard flavours can vary from one season to the next. Gemstones and grapes are both provided by nature. They need certain growing conditions: minute alterations as they mature can make huge differences to the final outcome. The main difference is the wine maker spends twelve months hoping that nature will provide the right weather, while the gem hunter has to pray that eventually he will uncover a perfect gemstone, one that was blessed with the right terroir over millions of years!
First, it is important to inform you that Emeralds have been found in different states within the vast country of Brazil and therefore no two locations share the exact same geological environment and mineralogical makeup, making it inaccurate to categorise Brazilian Emeralds as you would, say, with Zambian and Colombian, where they tend to be described generically. Instead it is necessary to evaluate the main producing areas separately. Although local Indian tribes knew of Emerald deposits over a thousand years ago, prospectors really started to explore in earnest the entire South American continent after the discovery of Emeralds in Colombia by the Spanish Conquistadores in the 1530s. Although the occasional discovery was made, it took over 400 years for a major break through. In 1963 at the mines at Salinas in the State of Bahia, commercial Emerald mining began for the first time in Brazil.
Minas Gerais (East Brazil)
This state is by far the largest gemstone state in the whole of Brazil, not just for Emeralds, but also Tourmalines, Topaz and many other gemstones. Just like Zambia and Colombia, its Emeralds are all found in an Emerald belt: the Minas Gerais belt is known as the Cinturon Esmeraldíferos. The belt stretches from Rio Cascade in the north, through Itabira, Nova Era and ends in the South at Guanhaes. In the belt the most well-known mines are the Piteira, Canaa and the vast Belmont mine. To get to the area you leave the capital city of Minas Gerais Belo Horizonte and travel 65 miles to the northeast. The Belmont mine is the second largest open pit coloured gemstone mine I have ever visited. Emeralds were first discovered in the area by mistake when an engineer repairing a railway track found a green stone lying on the floor. The gems in the region tend to be light green in colour and have good clarity. For more information about the area see the separate feature on the Belmont.
The state of Bahia is in the northeast of Brazil. Emeralds are found in various locations in the state: the first major discovery was in 1963 at Carnaiba, which lies some 250 miles to the northwest of Bahia’s capital Salvador. By 1969 it was reported that over 6000 artisanal miners (known locally as Garimpo) had descended on the area.
As the yield started to decrease from the Carnaiba deposits in the 1980s, many miners uprooted and moved to a new discovery just 30 miles to the northeast at Socoto. Whilst not always of the highest quality, Socoto Emeralds can be quite big; in fact it’s not uncommon to find specimens in excess of 10 carats. In both of these locations Emeralds are normally mined underground. Although I have not visited either of these mining areas I am reliably told that the mines descend to a depth of around 100 metres and then fan out in different directions, with some tunnels stretching over 250 metres. Most pieces are extracted still connected to the host rock and lower grade pieces are normally sold as mineral samples or used as carvings.
Some of the finest Emeralds I have ever seen in terms of colour saturation come from the Santa Terezinha mines. In 1981 during the construction of a road, workers found a gemstone that was so vividly green and with such incredible transparency that the first few people they showed it to did not believe it was an Emerald. Once correctly identified, there was one of the largest gem rushes Brazil has ever seen, with tens of thousands of Garimpo migrating to the area literally creating a new town overnight which is today called Campos Verdes, which translates as “Green Fields”.
Santa Terezinha Emeralds posses a wonderful pure green hue, the gem is vividly saturated and although each piece tends to have black spots, just like the Dalmatian dog, these often define their individuality. Unfortunately, very little is coming out of the ground at the moment and most pieces being offered for sale in the trade are from cutting houses who have, for investment purposes, locked away the gemstone for many years.
Regarded by many as the finest source for Emeralds on the planet, the gem has been mined in earnest in Colombia since the 1500s. That said, I have also read that there have been historical discoveries by archaeologists that date the use of Emerald jewellery in the region to around 500AD.
The main mining areas are to the west of Boyaca in central Colombia and located at the beginning of the Andes mountain range. Similar to the Fwaya-Fwaya Emerald belt in Zambia all of the mines are located in just one region, the main difference being that this Emerald belt (known locally as Cinturon Esmeraldíferos) is some 40 to 50 times more vast.
To the northwest of the belt in the Cosquez, Muzo regions are mines such as La Pita, Yacopi and Peña Blanca. To the southeast are the Chivor, Somondoco and Gachala mining areas. In addition to the larger scale operations there are hundreds of small scale artisanal pits and shafts, but unfortunately, according to my sources in the region, today there are as many guns as there are mining shovels and as many bandits as there are gem miners. Of course, this account is very different to the story that you hear from officials. There is a lot of work going on at the moment in Colombia to make the country a safer place to be and to reduce levels of corruption, but I fear it’s going to be a very long journey to turn around the current culture, so let’s pray for the safety of the miners and the community as a whole that officials are successful.
Emeralds from Chivor are similar in hue to Zambian Emeralds and tend to have a bluish green colour, whilst those unearthed at the Muzo mines generally have a better clarity and a yellowish-green colour and are described as possessing a warm, grassy green, velvety appearance.
Colombian Emeralds are often treated and enhanced in the rough and some processes are very difficult to spot, even by experts. My advice when purchasing Colombian Emeralds is that unless they are supplied with certification from one of the most respected gem laboratories stating they are untreated, it is safest to always assume some treatments have been applied. Historically, Emeralds from Colombia were treated with cedarwood oil. Although this is still the case today, the vast majority of these oils on the market are manufactured and not natural oil. Polymers are also frequently used; the main brands reportedly used in the region are said to be Araldite 6010 and Epon 828. Another common treatment is to use an epoxy resin; the main brand for years has been Opticon, but rather than using both elements of this two part resin it is reported that most rough gem dealers in the region only use the filler element and not the hardener.
Due to the inhospitable environment in which natural Emeralds are created, they will often have small cracks and crevices, which to unlock their true beauty need treating by man. The reason I have gone into more detail than normal regarding treatments of Colombian gems, is that it’s typically difficult to get a straight answer out of many suppliers in the region as to the treatments they have applied. Whenever my company creates jewellery featuring Emeralds from this area we always disclose the treatment which we believe the gem has undergone, however as it’s sometimes difficult to tell exactly what enhancements have been applied we always recommend to our customers that it is safest to assume it has had one of the aforementioned treatments. We also frequently update our website with new treatments as and when the gem industry discovers/uncovers them.
Recently at the GILC (Gemstone Industry Laboratory Conference) in Arizona, I was invited to participate in a discussion chaired by Gabriel Angarita, President of the Colombian Association of Emerald Exporters, where he openly spoke of how Colombia is trying to force its traders to be more open about the treatments they apply to their Emeralds. As of yet I have not visited Colombia, so I cannot provide you with my own account of the region.
Although today Afghanistan is a secondary source for Emeralds, nestled amongst huge mountains south of Asadabad in the Kunar Province are the Badel Emerald mines. These are probably the oldest gemstone mines on the planet that are still in use today and man first discovered Emerald there over one thousand years ago. I wonder if that makes it the longest continual business on the planet? Today, the quantity unearthed is very small and mining is now sporadic. A slightly more successful mining area is in the Panjshir Valley: here there are three different mining locations, but although several hundred people are said to be working the mines, we see very little evidence of this in terms of gems flowing in to the market.
When we do come across Afghan Emerald, they tend to have a vibrant saturation and a lovely, leafy green hue. One of its distinguishing features is that from certain angles you will normally see an internal whitish sheen when viewed under an intense candescent light.
Russian (Siberian) Emerald
In 2005 we purchased a rather large parcel of Siberian Emeralds. Although the tone was quite light compared to Colombian and Zambian, the gems were very open and possessed a wonderful inner life. The hue was as pure as I have seen in an Emerald. Unfortunately by 2006 we had sold every single piece from the collection and since that time I have not seen a parcel or been offered a single deal of comparable quality.
Over the past 12 months I have received three or four different requests to source Zimbabwe Emeralds. One of the reasons it is so highly sought after is that, just like the Emeralds discovered in neighbouring Zambia, the gems are normally a vibrant green colour and don’t normally need treating. Inclusions tend to be either Albite or Apatite in nature and the gems have a higher than normal chromium content, hence their very impressive saturated colour. They also have higher than normal refractive index (RI) and specific gravity (SG).
Emeralds were first discovered in Sandawana in 1956 and Modern Jewellery Magazine claimed they were “the finest Emeralds ever discovered”. The mine was once owned by the huge Rio Tinto mining company and 50 years ago the mine was producing consistent volumes of pieces over 1 carat. Over the past few years there has been very little coming out of the region, but don’t give up hope, as there is a lot of territory around the local mines where gemmologists believe the potential of finding quality Emeralds is high.
Please see the detailed feature on my trip to Zambia and my discovery of Zambian Emeralds.