Colombian Emerald Industry: Winds of Change | Gemstones and Gemology (2023)

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Colombia is synonymous with fine emeralds and production is believed to date back a thousand years. Over the centuries, the beautiful green gem, which grows in equally verdant areas, has been associated with violence and human exploitation. However, the desire of the Colombian people to mine this treasure and enrich it remains undiminished and enough dreams have come true to fuel their passion.

In recent years, changes in the industry have accelerated, perhaps more profoundly than ever before. While government ownership and regulation, criminal activity and violence have crippled production over the years, perhaps the industry's biggest opportunity is yet to come. Multinational companies are investing heavily in emerald mining in Colombia, which has led to modernization. The government's attitude towards emerald mining also improved dramatically during this period. Demands for transparency and traceability have led to the branding and reimagining of the industry. The loose system of independent miners (Figure 1) is undergoing formalization efforts. These groundbreaking changes come at a time when most of the country's emerald reserves have yet to be mined.

In October 2015, a joint team from GIA and Colombia gathered at the First International Emerald Symposium in Bogotá to interview industry leaders and government officials. Various topics related to change in the industry were discussed at the symposium. The team then traveled to Colombia's largest mines and visited traders and cutters in Bogotá to document the current state of the industry from mine to market. We were also able to collect rough emerald samples for the GIA laboratory's country of origin reference collection.

Mines that were once royal property of Spain came under the control of the Colombian government after independence in 1810. However, many independent miners were appointedguaqueros– continued digging in search of emeralds. In 1979, two companies, Tecminas in Muzo and Esmeracol S.A. in Coscuez, he initiated the privatization of the mining industry. Relations between the two groups became strained. Elements of Colombia's drug cartels tried to enter the industry in the 1980s, leading to the Green War in which thousands died. In 1990 a peace treaty was signed with the mediation of the Catholic Church. The key to the treaty was the legendary Victor Carranza, known as “The Emerald King” and considered the most important figure in the emerald industry at the time (Angarita and Angarita, 2013).

The past five years have seen an increase in foreign investment and the entry of multinationals into Colombia's mining industry, greater formalization efforts, greater transparency, stricter enforcement of traceability, less violence, and new branding efforts to create a marketable image for today's consumer.

As reported by Giuliani et al. (2015), emerald can occur in different geologic settings, but mainly occurs in three types of deposits: (1) igneous-metasomatic, (2) sedimentary-metasomatic, and (3) metamorphic-metasomatic. According to global production data from 2005, about 65% of global production came from igneous-metasomic deposits, while about 28% came from sedimentary-metasomic deposits and 7% from metamorphic-metasomic deposits (Giuliani et al., 2015 ). The emerald deposits of Colombia are of the sedimentary-metasomatic type.

Northwest Colombia is located at the intersection of three major tectonic areas: South America to the east and south, the Caribbean to the north, and the Cocos and Nazca oceanic plates to the west (Figure 3). The Colombian Andes are the most significant surface features resulting from the interactions between the three regions throughout Earth's history. Since the end of the Cretaceous period about 70 million years ago, the convergence of the Nazca-Cocos oceanic plate with the South American tectonic plate has played the most important role in shaping the topography of the region (Colletta et al., 1990).

From the Tierra del Fuego archipelago to Ecuador, the Andes consist of a single, narrow mountain belt, but in Colombia the Andes further north split into three arms, forming a trident-shaped topographic feature (Figure 3). These three ranges are the Western, Central and Eastern Cordilleras. The latter is also known as the Cordillera Oriental. The three areas are geologically distinct and formed at different times (Irving, 1975). The Cordillera Occidental consists mainly of Late Cretaceous ophiolitic rocks, while the Cordillera Central consists of Precambrian and Paleozoic rocks intruded by Mesozoic plutons. The Cordillera Oriental is characterized by a thick and folded Mesozoic and Tertiary sedimentary succession superimposed on Precambrian and Paleozoic basements (Colletta et al., 1990). Convergence of the Nazca-Cocos plate with the South American plate was partly absorbed by subduction along the Colombian-Equatorial Trench and partly by uplift of the Cordilleras Orientals.

All of Colombia's emerald deposits are located in the Cordillera Oriental. Today, the western zone of the Cordillera Oriental is defined by a series of western thrust faults and the eastern zone by a group of eastern thrust faults (Figure 4). The entire region is bounded by the Magdalena River Valley to the west and the Llanos Basin to the east. During the middle Miocene (peak about 15 million years ago), active movements of convergent plates led to severe shortening in the eastern Cordillera region and uplift. This scenario is the geologically known phase of the Andes. It is noteworthy that the Colombian emeralds formed before the Andean phase.

In Colombia, emeralds are mainly mined from shale rocks of the early Cretaceous period. The shales were among the upper fills of a coastal basin in the Cordillera Central that began in the Jurassic and matured in the Late Cretaceous. Subsequently, inversion of this basin before and during the Andean phase produced the relatively high topography of the Cordilleras Orientales and some of the local structures for emerald crystallization (Colletta et al., 1990; Branquet et al., 1999).

Previous surveys and field research have defined two zones of emerald occurrence along the two boundaries of the Cordillera Oriental (Figure 5). The western zone includes deposits such as La Glorieta–Yacopi, Muzo, Coscuez, La Pita and Peñas Blancas. Along the eastern belt are Gachalá, Chivor and Macanal (Branquet et al., 1999). Emerald mineralization is associated with the circulation of hydrothermal fluids and is therefore strongly driven by structural evolution in each zone. Emeralds are found in Early Cretaceous shales in both zones. Although Emerald formed under similar geochemical conditions on both sides, mineralization of the East Zone occurred about 65 million years ago in an extensional environment, while mineralization of the West Zone occurred about 33 million years ago in an extensional compressional environment (Branquet et al., 1999).

In the Western Zone, emeraldine mineralization occurred when hydrothermal brine intruded the organic-rich black shale. The hot brine created when the liquid was heated dissolved the vaporizers. The salt domes north of Bogotá are surface evaporites beneath the emerald black shale (Figure 5). When the basin was overturned, some of the lower layers, such as the salt layers, were pushed out and brought to the surface. The hot brine either migrated through faults and other structural weaknesses in the black shale or seeped out.

Deposits in the western zone are strongly controlled by thrust faults perpendicular to the thrust front (Branquet et al., 1999; Giuliani et al., 2015). Thrust faults are steep outcrops embedded in rocks that have a very strong flow component and are usually formed to accommodate the different migration velocities of the thrust fault. The nearly vertical faults provided ideal channels for the hydrothermal brine to migrate and infiltrate the surrounding rocks (Branquet et al., 1999). During this process, the brine absorbed the necessary components for the formation of emeralds from the surrounding shale (Pignatelli et al., 2015). As the temperature dropped and certain chemical constituents reached saturation point, emerald began to crystallize in the veins of the foot along with other minerals such as calcite, quartz, albite and pyrite.

The Western Emerald Zone is located in the center of the Villeta anticlinorium (see Figure 5). Its general stratigraphy includes, from bottom to top, the basal rift (probably where the evaporites are located), Valanginian-Hauterivian dolomitic limestones, Hauterivian calcareous shales, Hauterivian siliceous shales, and Barremian-Aptian mudstones (Branquet 1999). . Emeralds formed within hydrothermal breccias or siliceous-carbonate veins in dolomitic limestones and calcareous black shales (Branquet et al., 1999). In individual deposits, emeralds are mined along compressional structures such as thrust faults.

In the eastern zone, emeralds formed much earlier. The current topography and structures are the result of the uplift of the Andean phase (see Figure 4). Shortening during uplift is compensated by many overthrusts and folds, so that the structures of the pre-Andean phase are imprinted. However, structures in some of the important emerald deposits indicate an extended environment. Coupled normal faults, extensional fractures and flashes are some of the features that indicate the local stress field at the time of crystallization of emeralds. All of these structures originate from a predominantly mineralized breccia layer (Figure 6) and it appears that the formation and evolution of these structures occurs concurrently with hydrothermal fluid circulation and emerald formation (Branquet et al., 1999, 2015). As the extension took place in the regional compression environment and was very limited, the cause is still unclear. Unlike its eastern counterpart, the western zone does not exhibit a local level of evaporative vacuum.

The 2015 mission had three main objectives: presentation at the Emerald International Symposium in Bogotá; document the Colombian emerald mining industry for the market, including the massive changes taking place in it; and collect rough emerald samples for the GIA laboratory's Country of Origin database reference collection. We also renewed our relationships with Colombian industry and created new ones.

Andrew Lucas led the industry documentation project. Jonathan Muyal managed sample collection. and cameraman Pedro Padua filmed the video interviews, industry activities and the sample collection process. Colombian field guide and gemologist Darwin Fortaleché handled the logistics, providing insightful guidance and commentary and recording the GPS coordinates of active tunnels, minefields and minefield markets. Our experienced guide, Miguel Gonzalez, who was also involved in emerald mining and trading, provided information and helped guide the expedition.

We were able to capture all major mining activities in one trip through the verdant landscape of the Colombian Andes (Figure 7). In Bogotá, we are looking at the areas of cutting and selling emeralds. More than 44 hours of video and 10,000 photographs were recorded, including on-site interviews with miners, cutters, traders, industry leaders and government officials.

We arrived in Bogotá on October 12, 2015 to participate in the three-day symposium. There, the GIA team made presentations, finalized the mission plan and interviewed officials about the recent changes. The next two days were spent documenting the cutting and trading of emeralds in Bogotá and meeting with representatives of the Colombian industry.

At dawn on the 18th of October we left Bogotá for Chivor. The route took us first to the eastern zone mines of Chivor and Gachalá and then to the western zone mines of the Coscuez, Muzo and La Pita areas. We stayed in minefields and hotels in nearby towns. The town of Muzo served as a base for exploring the mines and active markets in the western mine belt. The pace was fast and we often had to drive at night so we could see as many mines and markets as possible in the time we had. On November 1st we were back in Bogotá to prepare the legal export of the rough emerald samples with licensed export brokers and start the return flights. Our mission was short due to the goal of visiting all the main mining areas in Colombia and documenting mining and trade, but we were eventually able to cover the entire sector from mine to market.

Montenegrin father Pedro Pablo started working at Chivor in 1965, first as a cook and later as a miner. After finding some profitable emeralds, he took his share of the profits and began buying stones from the mines and selling them to merchants in Bogotá. As his earnings and experience grew, he expanded his business, opening an office in Bogotá and began cutting and selling the finished stones himself. Changes to mining regulations in 1991 paved the way for further privatization of Colombia's emerald mining industry. This led Montenegro to open its own mining concessions in 1993.

To reduce burden and investment risk, most mining operations in Colombia are based on partnerships. Mr. Montenegro operates five concessions in the Chivor area, totaling 140 hectares, with interests in three additional concessions under development. It currently works in 15 tunnels in its five existing concessions – including the San Pedro, San Gregorio, El Manantial, Oriente, Piedra Chulo, Quebra Negra and Gualí mines – with around 15 miners each. In total, about 50 tunnels were operating in the Chivor area, and Montenegro said there were about 15 concessions with working tunnels.

When working with partners, Mr. Montenegro is the owner of the mining concessions or permits. In Colombian emerald mining, a consortium typically consists of the licensee, who owns 50% of the concessionaire, and the partners, who pay for expansion and operations and control 50% of production. This amount can be deducted from exploration, prospecting and other work to be agreed with the investors. Mr. Montenegro holds the mining license at El Manantial and has attracted investors to cover operating costs in some of the productive tunnels. He said he keeps 50% of the profits and the rest goes to investors and miners.

The miners employed in Montenegro, like many others in Colombia's emerald mines, prefer to receive a percentage of profits rather than just a salary. Miners are usually paid a basic salary with benefits, food and housing, but their main draw is profit sharing and the ability to keep and sell some of the production themselves. In that sense, they have the same incentive as homeowners to find emeralds.

For new concessions, Montenegro was awaiting pre-mining environmental impact assessments and looking for investors. For each of these concessions, he commissioned an advanced geological study to approach mine design in a more modern way. He also considered more mechanization than usual in Colombian tunnel mining, which is more like artisanal mining. With geological mapping and mine planning, in addition to more modern and larger operations, he predicted that the production currently achieved in a year would be achieved in a month. Because Chivor emeralds tend to be bright and pure, qualities highly sought after in China, he traveled there to meet with investors.

Mr. Montenegro said it managed to stay competitive by exporting the stones and moving them through the entire wholesale value chain of machining, cutting and selling on the global market. Because emeralds don't change hands, he can avoid prizes. In addition, there is the advantage of being able to guarantee a complete product chain. This assures buyers of the legitimacy of their purchase and provides a documented supply chain, including the type of filler used in the treatment.

After our first day at El Manantial, we visited several working tunnels and recorded the San Gregorio mine, owned by the SOESCOL company, of which Mr. Montenegro is the majority shareholder, and the Dixon and Tesoro mines owned by the San Francisco Company. We also observed small-scale processing outside the tunnel in the Chivor area (Figure 12).

At Dixon and Tesoro, the San Francisco company employs 14 miners on a permanent basis, with seven more on standby if a pocket is discovered. Garimpeiros work from 7am to 4pm. 20 days straight and then 10 days off. Dixon mine manager Giovanni Lopez, who has worked there for 22 years, summed up the outlook for miners. Although they've made a living producing small bags over the years, they're not just aiming for a monthly income: they're aiming for the big payday. Mr. Lopez said that if he got a big bag and became rich, he would invest in other businesses to ensure a steady income and keep looking for another big bag because of the adrenaline that comes with finding value.

Explosives are a necessity in emerald mining in Colombia. Water gel explosives approved for emerald mining must be purchased from the Colombian military weapons manufacturer Indumil and stored in a secure location according to strict guidelines. The Chivor area has a military presence and the explosives storage area of ​​each mine is guarded by private security forces. Miners who handle the explosives must be certified by the government.

At Tesoro, we saw typical Colombian drilling and blasting techniques (Figure 13). One of the more difficult guesses was how fast you could get through the rock into a productive zone without exploding in a pocket and destroying the emerald crystals. The locations of the holes also had to be carefully planned to avoid damaging the emeralds.

The miners drilled holes about an inch in diameter into the mine wall, the length of the hole depending on how far they wanted to go. The detonator was inserted into the explosive loaded into the drill holes with the detonating wire protruding from the hole. A separate fuse was used to light them all. We had about a minute to get to a safe area of ​​the tunnel. After the explosion, the wall was examined for signs of an emerald pocket. After the debris was cleared, the process was repeated. Deciding when to detonate is difficult, as the need to reach pockets of emeralds must be balanced against the risk of destroying valuable material.

To install Gachala.Arriving in Gachalá de Chivor, our first stop was the company Mina La Emilia. We were welcomed to the Diamante mine camp by the main owners Camilo Sanchez, Benito Mendez and their son Christian Mendez who is also the general manager of Mensal Emeralds. We immediately began investigating the emerald threat from her tunnels and others in the area. We also know of a Chinese buyer known to author AL who was buying rough emeralds. The buyer was looking for the clean, polished material that the Gachalá and Chivor regions are known for.

The next day we took a detailed look at El Diamante, La Estrella and El Tesoro, all mined from Mina La Emilia. In Colombia, the name of the concession is often shared by one of its tunnels, in this case the La Emilia tunnel. When referring to the mine from which an emerald came, traders may use the name of the concession or tunnel. La Emilia Concession had four active tunnels at the time of our visit.

El Diamante is over 20 years old and began as a vertical shaft with an elevator that descends 48 meters to reach a tunnel that leads to a second internal vertical shaft. Here we go down with a harness, calledthe scope, which was lowered with a winch. The second shaft led to subsequent tunnels and further internal vertical shafts. The production zones were located in the tunnels on the first level, which we reached by elevator. As we proceed, we see a common sight in Colombia's emerald mine tunnels: the use of wooden supports for structural integrity. Groundwater was abundant in the mining areas, which stressed the supports and rotted the timbers.

As we passed El Diamante, we saw several wooden supports breaking. Additional struts had to be built and, in extreme cases, the entire tunnel strut construction system had to be replaced. New devices often sit next to broken devices.

In following up on the productive excavations, El Diamante management used a more systematic and thorough exploration methodology. They initially explore 1,800 meters of level, following the mineralization and analyzing every 50, 70 or 100 meters, depending on the geology. If they get within 100 yards with no signs of a productive zone, look for an opposite face. If nothing is found on the opposite wall, they build a cross tunnel leaving a space of 25 meters parallel to the first and return for further explorations. When they reach the end of the concession area, they stop, go up or down 10 meters and repeat the process.

The pocket we reached was hammered to progress along the calcite vein. They hadn't yet reached the emerald pit where the crystals could be manually mined, but they were close enough that they didn't want to rush into the production zone.

Next, we visit La Estrella, a ramp-shaped mine that is less than a year old. While El Diamante had a good production record, La Estrella had not seen any significant production at the time of our visit. However, there were encouraging geological indications that it would be a significant producer in the near future. We went through the tunnels to an area where the lead geologist was working, who used pickaxes to dig out the calcite vein. He thought that all they had to do was dig deeper into this zone to reach a huge bag of emeralds.

While waiting to get into La Estrella, we talked to the Mendezes. The elder Mendez worked in the emerald business for more than 50 years. He was now 82 years old, although you would never know it from the way he moved on the trails and in the mines. He began trading emeralds in Peñas Blancas, Coscuez and Muzo and later turned to mining. In the 1980s and 1990s, he found that mining and doing business in Gachalá was safer than in the Muzo and Coscuez regions. He also preferred the cooler climate and moved to Gachalá more than 20 years ago, first in open pit mining and later in tunnel construction.

The family has other concessions in Gachalá and Muzo. The entire production is transferred to Bogotá, where the partners organize an auction among themselves. Winning partners can sell the rough to cutters in Bogotá or cut it and sell the stones to buyers around the world. If the Mendez family wins the auction, they cut production and sell it. They use independent stone cutters in Bogotá who are selected based on the type of stone and their cutting skills.

Meanwhile, Christian Mendez is trying to expand the business to the global market. Its global customers include retail jewelers, jewelry manufacturers and other wholesalers. China is the most important customer and the United Arab Emirates is another strong market. The American market accepts all qualities of the Mendez family, while the Chinese market prefers fine colors and very high clarity and luster, or very large stones of more moderate quality. The UAE is a diversified market for them, as the rich and royals want the best and biggest stones, while some jewelery retailers are looking for mid-range commercial products.

The family wants to move up the value chain and eventually sell emerald jewelry to retail customers. Christian Mendez spoke about the future of the industry in terms of foreign miners. He pointed out that the country can benefit from investment in mining, increased production, job creation and higher tax collection. At the same time, it sees Colombian traders and cutters struggling to survive as access to rough emeralds is limited.

El Tesoro was the third tunnel we visited in La Emilia. It started as a vertical shaft, like El Diamante, but only used a winch system. The harness led us to the first level where a tunnel led to another vertical shaft with wooden stairs to the tunnels that housed the production zones.

On our last morning in Gachalá, we visited three more tunnel mines - El Toro 1, 2 and 3 - a total of six mines we saw in the area that were either in production or being explored to reach productive zones. To get to these mines, you had to trek through the mountains. El Toro 1 was about a year old and had yet to produce an emerald. There were no clear markers in the tunnel for the miners to follow. El Toro 2 ran for about seven months. The area we visited had been under construction for four months. The tunnel was 102 meters long and there were some indications that emeralds could be found there. It had no wooden beam supports and could work for a while without supports. El Toro 3 had the highest activity of the three El Toro mines at Gachalá.

Mining markets in the eastern zone.The Eastern Emerald Belt lacked the large organized mining markets we would later see in the Western Emerald Belt at Coscuez and Muzo. The miners sold emeralds in front of the gate, in the mine warehouse and even in the halls. Miners and merchants in the city of Chivor sold emerald blocks to homes and offices, as well as on the streets. More material was available in Chivor, but there was clear interest from buyers in Gachalá. Author JM was able to purchase many raw samples for the GIA reference collection directly from the miners, including their most recent production.

As we entered La Paz, we saw car after car being pushed to the exit. Open carts containing only slate were removed from the tunnel as the miners advanced. The closed and locked carts contained emerald slate. Meanwhile, water was constantly flowing from the tunnel.

We walked 1,650 meters to the first elevator, from where we descended 48 meters to a second elevator. This took us down another 35 meters to another shaft and elevator, which descended another 48 meters to a tunnel leading to a production zone. Many tunnels were built at different levels. The material was packed in white bags, placed on carts and taken to the elevators to be sent to the upper tunnel and removed from the mine. The unloaded empty carts being pushed back into the work areas constantly passed the loaded carts, with plenty of room for both.

Between the second and third wells in La Paz are two tunnels for air circulation and another vertical well called a "chimney" for the discharge of polluted air. The heat (with temperatures often exceeding 40°C or 104°F) and 99% humidity were exhausting and often rendered our cameras impossible. Black shale dust is constantly in the air and even masks and respirators do not prevent it from entering the miners' lungs. Outside the tunnel, their faces were covered in black shale (Figure 15) reminiscent of the miners of a century ago.

Miners work eight hours a day, five days a week. There was some emerald production at the time of our visit, but nothing "significant" according to Mr. Rodriguez. Nevertheless, 98 miners were working in the La Paz tunnel, and the total number of workers was 105.

After returning from the El Chacaro mine market, we spent the night in the small but very lively town of Otanche, with people on the streets and soccer games in the park. The next day we visited three other active mines in the Coscuez area: Pavimentado, Bonanza and Terraza, all owned by Esmeracol S.A. We interview mine manager Andres Murcia and head into the tunnels, starting at Paved.

After walking through the approximately 1,200 meter long tunnel, we had to crawl into a production zone where miners were extracting emeralds from a wide vein of calcite. The heat and humidity got to a point where the camera lens constantly fogged up and had to be cleaned of condensation before shooting. We could see emeralds being extracted from the calcite veins with a hammer and chisel. After all visible emeralds were removed, the miners drilled holes around the pocket and set the explosives to detonate further down the vein (Figure 17).

As with the Tesoro tunnel in the East Zone, the fuses had to be cut long enough to allow everyone time to crawl out of the tunnel to a safe distance from the blast. After returning to examine the bag, the miners drilled to remove more calcite and uncovered more emeralds that had to be extracted with hammer and chisel.

Bonanza and Terraza were the hottest and wettest tunnels we visited. Steam billowed from the inlets, the cameras immediately dimmed. Both were smaller facilities than Paved. Then we go back to El Chacaro market and then to Muzo.

Let's go.Once in Muzo, we went to the street market and perused the rough emeralds for sale. The first tunnel we visited was El Amarillal, operated by Mina Real Limitada, where we interviewed mining engineer Carlos Diaz. The company owns 12 tunnels in the concession. A few years earlier, Mina Real commissioned a geological survey to identify potential production zones and look for geological faults. When potential zones are identified, mine operators focus on those specific zones and determine the exploration method that will not damage the tunnels. Depending on the economic potential, exploration methods are different for each mine. Mines with higher potential are more mechanized and have more workers (C. Diaz, personal communication, 2015).

First, miners break up the hard rock with explosives. Using compressed air and hammers, blast holes are drilled 1.2 to 8.0 meters apart, into which the explosives are placed. The explosives operator has completed Army certification courses. He sets off the blast, which shatters the rocks, and workers use shovels to fill the cars with gravel and carry it to the trucks.

A different system is used in production. A company manager (in a white helmet) and a partner (in a red helmet) take control of the exchange. They place a large amount of emeralds in a locked cabinet and take it to a laundry. The emeralds are measured and weighed, then sorted and placed in other sealed containers. These stones are separated and offered for sale at a meeting of partners and investors.

The company employs about 60 people, including inspectors, agents and miners. El Amarillal itself employs about 40 people, half of whom are from Minas Gerais. (There are also about 200 Guaqueros working along the river in this zone.) Each work area has a budget for wages and labor support, and administrative staff are also paid. Employees receive support with their monthly expenses. During production, workers receive a share of the raw material mined each day or a share of the profits from its sale.

Before the start of tunnel excavation, the company used mechanical open pit mining. Although this method exposed many veins of emeralds, the environmental impact was severe. Good production was recorded in the tunnel mine area, not only at El Amarillal, but also on the neighboring company's property. Guaqueros also found valuable emeralds in the river. When it was still an open pit mining operation, there was more independent mining activity, mostly along the river. Diaz acknowledged that operations would be more efficient with modern equipment, but that requires significant investment, often from a foreign company.

Mina Real is now about a third into a 30-year concession with the National Mining Authority and is progressing from exploration to production. They expect results because they have a contract of two decades and have reached the productive zone. The concession was once owned by Victor Carranza, who returned it to the state before Mina Real Limitada bought it.

The company's emerald sales will initially be made through the same 14 partners, consisting of companies or independent traders who make offers to mining representatives. These partners include some emerald exporters. From 2011 to 2015, the mine produced 380,000 carats of rough emerald worth $700 million.

The El Amarillal main tunnel had lighting and ventilation ducts throughout and was typical of the best managed tunnels in Colombia. It was hundreds of meters long and branched off into other tunnels and shafts. There was a lot of activity, people were drilling and blasting, emeralds were being mined and brought in by wagons. We also watched the groundwater struggle as a miner tried to dig a well that was constantly filling up.

Itoco-Flow.We had the opportunity to document two very different activities along the Itoco River, a tributary of the Minero River: artisanal mining on the banks of the river and thousands of residents washing the waste and ores of a large mining operation.

We were also there two mornings when Minería Texas Colombia (MTC) trucks brought waste and unwashed ore to the river banks and made it available to the locals for washing. It was a fascinating sight: a line of trucks came down the hill from the MTC mining area at regular intervals to cross the flat section of the river, slowly raising their hydraulic beds to dump the waste without ever stopping. Residents crowded around passing trucks and litter was scattered to minimize crowds.

At first glance, the scene appeared to be a frantic scramble to collect and pack the debris (Figure 19). Upon closer inspection, it was clear that there was organization (Figure 20). Many groups worked together, probably families and neighbors. The strongest members of the group fought to the waste and wrung the material. These bags were taken to the river to be washed with mesh type screens while the others continued to pick up as much trash as possible.

Women participated in all phases of the business, from garbage collection to washing. Virtually everything was covered with black slate. Meanwhile, several buyers waited nearby to make offers. They were easily recognized by their clean clothes and the traditional white towel hung around their necks, which was used to clean the emerald before examinations. If the locals couldn't immediately get the price they wanted from the riverside buyers, they would simply walk up the hill to the La Playa market to find a better deal.

Texas Columbia Mining.We spent a full day at the MTC Emerald Mine, which is part of Muzo Emerald Colombia. Mine manager Carlos Contreras Cañizo, originally from Mexico, had experience in gold mining using modern methods. He compared the two types of mining.

“With gold, you look for veins and you can expect a fairly predictable range of how many grams per tonne you're going to produce. This can easily be mapped through core sampling and geological studies. With emeralds, you follow the indicator minerals and find more pockets than you would with a relatively even distribution. With gold and emeralds, the more land you mine, the more material you can mine.

"But with emeralds it's much more difficult, if not impossible, to predict the quantity per ton and much more difficult to predict when you'll find them." The other factor is that the gold extracted from a mine has almost the same value. However, the value of mined emeralds can vary greatly and it is not possible to predict where the most valuable material will be found.”

Even for a large and sophisticated mining operation like MTC, predicting where to find the highest quality emeralds is a challenge. Cañizo said it's about "fifty percent knowledge and hard work, fifty percent luck and God bless you."

In 2009, MTC was a partner in the Muzo mines, including the famous Puerto Arturo mine. Mr. Cañizo had envisioned the creation of ramps that would connect the different levels with a central vehicle ramp and transport miners through the same shafts used for ore and machinery. At the time, MTC was operating Puerto Arturo in partnership with Coexminas, the Colombian company that had controlled the mine since 1977. One of Coexminas' three main partners was Victor Carranza, the "Esmeralda Tsar". Production was split equally between the two companies. Part of the agreement was a clause that said MTC must dig 3,200 meters of tunnel or withdraw from the deal, limiting the mining method Mr Canizo could pursue. After Mr. Carranza's death in April 2013, MTC acquired the mine and began implementing a ramp and new methodology.

The MTC mines the emeralds in a similar way to other Colombian tunnels, using drills and hammers to reach the emeralds and then picking them by hand to extract them. They also use a similar washing process for sieves, water and human muscle. MTC operates six mines or galleries: Palo Blanco, Puerto Arturo, Tequendama, Catedral, Pablo Sanchez and Matefique (the latter two employ contractors). The main producing mines are Puerto Arturo, Catedral and Tequendama.

Puerto Arturo is currently the deepest well at 152 meters, while Tequendama is about 85 meters deep and Catedral has two wells, one 20 meters and the other 60 meters. When Mr. Cañizo took over the management of the mine, all the pits were independent of each other. They are now connected by tunnels and the goal is to create a ramp that crosses the tunnels that are currently being produced. The La Rampa tunnel is spiral and extends about 400 meters underground to connect all the tunnels. La Rampa is MTC's testing ground for geological research and optimized mining techniques.

Direct production can be dramatic. As of May 2015, the MTC has recovered 152,000 carats from one area, including large stones weighing up to 1,200 carats. The total yield for 2014 was over 240,000 carats, and at the time of our visit in November 2015, it had produced 384,000 carats that year (C.C. Cañizo, personal communication, 2015).

After washing the ore, emeralds are divided into four grades: precious (large sizes, high quality, intense color);little star(small sizes, high quality, intense color), tinted crystal (good shape, light to medium tone), andmold(bad quality). The rough stones are placed in envelopes indicating the weight, basic grade classification and tunnel of origin, and then collected to be sent to Colombia Texas Transformadora (CTT), a grinding plant in the Free Zone of Bogotá.

Muzo Emerald Colombia invested more than $50 million in the modernization of the MTC mine, including ramps to connect the tunnels. The mine employs over 800 people (Figure 21), many from the surrounding communities. They also support local schools and a health clinic that serves over 1,000 local people (Burgess, 2015).

I am doing.As in Muzo, mining activities in the Maripí region have changed significantly in recent years. In 2011, two of the authors (DF and AL) visited mines in this area along the Rio Minero, including La Pita, Cunas, Totumos, Polveros, Los Españoles, Bonanza and Consorcio, which were not operating at the time of this visit .

In the Maripí region, we started in Polveros and Los Españoles, documenting the mining activities in the latter and interviewing mine manager Fabian Arango. Los Españoles has been working for about 30 years, but since 2011 the company has become professional in its methodology. Typically, 15 miners are employed in the tunnel. We saw a continuous flow of trucks between the mine and a shed where the material was washed through mesh screens (Figure 22). The tunnel branched into others, with the tunnel to our left containing a job production zone. There was also a 60-meter vertical shaft leading to tunnels containing production zones, but groundwater entering the lower section had to be pumped continuously.

After a significant production, the mine management calls the partners, who distribute the commodity to the shareholders. The mine's management and partners seal the emeralds and bring them to Bogotá, where they select the stones to be cut and the stones to be kept as rough specimens. But first, miners can go through the rough test and, together with the management, determine in what proportion and what qualities they will receive for self-sale. The percentage of production they receive is added to their pay package, which includes pension and benefits. The last significant harvest was in December 2014 in the production zones in the tunnels extending from the vertical shaft.

You give pie.At La Pita, we took an extensive tour and interviewed mine manager Javier Puerto, who has over 20 years of experience in emerald geology, prospecting and mining. Directed by Zuliana de Esmeraldas, La Pita opened in 1995. The first major production took place in 1999, when miners found an emerald pit. Mr. Puerto started working for the company that same year, when the tunnel was already 1,200 meters long. The concession covers approximately 39 hectares. Mr. Puerto said there has been constant work at the mine since his arrival. He noted that the deposit is a single zone of mineralization that stretches from Polveros, Totumo, Cunas, Consorcio and La Pita to Puerto Gringo.

We entered the mine from the central gallery and descended 625 meters to the first vertical shaft, which was 35 meters deep. At 700 meters we find the second well with a depth of 42 meters. A hundred meters ahead was a pit 44 meters long. Two other wells, both much shallower, have filled with water and are currently unused. If a surface is left untreated, the acidic water will erode the wood structure and rust the metal within months. We went through all the levels, with the fifth level being 110 meters below the main tunnel floor. In each level we visit all production tunnels and most tunnels under exploration. The current mine extends from 120 meters below the mine floor to 30 meters above.

La Pita has several emergency exits in case of flooding, including a north-facing exit at Puerto Gringo and a ventilation shaft. Using an extractor, the air is channeled into the tunnel and down each shaft, through the work areas and out through the chimneys. As a result, the air in the tunnel and shafts is extremely fresh and free of gases that can accumulate in a mine: sulfuric acid, carbon monoxide, carbon dioxide and even nitrogen oxides, a byproduct of explosives. The pipes carry energy from the surface and an internal control station reduces the loss of energy involved in transporting it to a distance.

The company hires local employees to ensure the greatest benefit to the local community. They employ around 120 people per shift, in two shifts – from 6am to 2pm. and from 2 pm to 10 pm

Mr. Puerto noted that emerald deposits are geologically very different from other types of deposits. Most other minerals are mined geometrically: miners look for a bed of a certain thickness, width and length, meaning consistent production can be controlled throughout the week, month and year. In emerald mining, production zones are variable and production is never constant. Companies can spend two or three years preparing a mine or recover emeralds in just 15 operating days. Every time miners go deeper into a Colombian emerald tunnel, the water level rises and mining becomes more difficult. Exploration for new veins and pockets through horizontal levels usually takes a year or two to find the veins. A single vein can be searched for a day, a week, a month or more. Emeralds are never found in many veins.

According to Zuliana de Esmeraldas geological surveys, only 8-10% of the La Pita deposit has been explored so far. They plan to improve the transportation system to increase production. They currently use the same carts (Figure 23) found in the Esmeralda tunnels in Colombia. They plan to install a mechanized system with automated inclined rails to move materials. To manage groundwater as it sinks deeper, they drill wells vertically and pump the water (J. Puerto, personal communication, 2015).

Mr. Puerto stressed the importance of identifying rock type and structure in emerald mining. In sedimentary deposits, structures such as faults are particularly important for emerald crystallization. In the Western Zone, almost all emeralds formed within compressional structures such as reverse faults and faults. Faults cut through the organic-rich calcareous shale and provide the space, while the shale and hydrothermal fluids provide the necessary ingredients to mineralize the emerald. In the tunnel, geologists and miners monitor two large parallel faults, the Río Minero and La Pita. The La Pita fault is an inverted fault, a typical structure that develops in a compressional environment. Calcareous shale, the main component of the Muzo Formation, is the target rock for miners. After identifying the host rock and structures, researchers look for mineral markers to track the emeralds.

Zuliana de Esmeraldas has a two-tier distribution protocol. There are about 18 members and each one comes in person or sends a representative. The company extracts the emeralds, taking care not to break the crystals, and bags them in the presence of the partners. The bags are sealed and locked in a safe and an associate or representative holds the key. Once enough production has been gathered for the partners to sell, they wash and weigh the emeralds and place them in a security bag. The company's shareholders remove the emeralds in front of everyone. They verify signatures, ensure all procedures have been followed and schedule an auction. Foreign dealers sometimes come to the auction and deal with people who know or buy the emeralds.

Mr. Puerto pointed to three major production periods for La Pita beginning in 1999 in the southern sector. They drilled wells, conducted surveys and geological surveys, and moved into the northern range, where they had good years in 2001 and 2002. They recorded large production at ground level in 2007 and 2008, followed by significant yields in 2010 and 2014. La Pita's production since 1999 is known to have exceeded $1 billion in gross value.

cradles.The Cunas mine, owned by Esmeraldas Santa Rosa S.A., has become one of the most important producers in Rio Mineiro. The Cunas mine camp is above the tunnel and the path to the mine was heavily guarded. The tunnel extended several hundred meters into a shaft containing a productive working zone. It was a typical Colombian emerald tunnel mine, but very different from La Pita, particularly in terms of temperature and air quality. Although Cunas also had vent pipes and mechanical pumps for circulation, it was much hotter and humid there, reminiscent of the Pavement and Bonanza mines at Coscuez. The water running through the mine sometimes came up to our boots and the air had to be monitored for the build-up of dangerous gases. The ore was transported from the mine and the emerald-bearing material was identified when it was removed from the rock face, bagged and sealed, and placed in a vault.

Joint venture.The Consorcio mine was closed at the time of our visit. When author AL visited in 2005, it was one of the most productive mines in Colombia. Prominas de Zulia, now Zuliana de Esmeraldas and also the owner of La Pita, was the first owner of the Consortium when the company was discovered in 1999. The initial production was impressive and in 2001 Victor Carranza became a partner. The company later created was Consorcio Minero, 50% owned by Esmeraldas Santa Rosa (owner of the Cunas mine) and 50% by Zuliana de Esmeraldas. The estimated production value between 2001 and 2008 was approximately US$1 billion (J. Puerto, personal communication, 2015). A 2008 burglary resulted in Mr. Carranza and the eventual termination of the contract between Esmeraldas Santa Rosa and Zuliana de Esmeraldas, and the mine was closed in 2015 due to ongoing litigation.

Mining markets in the Western Zone.As in Chivor, Western Belt miners often sell rough emeralds at midday or at the end of the day. In larger mines, locals often wash their waste and keep the emeralds they find. However, there are some very structured mining markets in the western zone. The largest are Mercado La Playa on the banks of the Rio Itoco, Mercado El Chacaro in Coscuez and Mercado La Pita mines in the Maripí area.

The El Chacaro market was a hive of activity as miners and traders offered a wide range of crude types and sizes for sale. When writer AL was there in 2005, it was not unusual to see armed miners and traders. This time there were no guns in sight and there was more trade. The market also featured restaurants, bars and gambling opportunities. When prospectors and traders saw a potential buyer, they would put down their drinks or step away from the gaming table to show off their emeralds. There was a lot of activity on the road, with the mountains and mines in the background. Author JM received many emerald samples from miners here.

Also in the Muzo area, we visit the La Playa market on top of a hill overlooking the Río Itoco and the Minería Texas Colombia mining area. It was here that many independent miners and traders sold uncut emeralds. The morning was full of activity, especially after the MTC trucks dumped their waste in the river and thousands of villagers passed by. After the big trade, the garibeiros relaxed in the makeshift bars of the small market (Figure 24). One of the most striking scenes was a man and woman covered in black slate examining a rough emerald crystal from the MTC waste heaps.

In 2014, the Colombian emerald industry exported more than two million carats valued at US$147 million, mainly to the United States and Asia (Angarita, 2015). For a complete overview of the industry, we return to Bogotá. Our first stop was the Centro de Desarrollo Tecnológico de la Esmeralda Colombiana (CDTEC), a filling laboratory and research center. We then visit merchants and tailors in the Emerald Trade Center, as well as street vendors outside the center.

The former General Director Dr. Carlos Julio Cedeño guided us through CDTEC, a non-profit organization founded in 2008 that is partly owned by the Colombian government and partly owned by major trade associations, including Fedesmeraldas. CDTEC's mission is the research, identification and certification of precious stones, mainly emeralds. Its laboratory reports identify the material and the type of processing and certify the Colombian origin. They are also involved in testing a natural filler (developed by commercial associations) that is durable and can be removed and refilled, as well as researching the origin of Colombian emerald through chemical fingerprinting. CDTEC analyzes approximately 70% of high-tech products that leave the country (G. Angarita, personal communication, 2017).

Built in 1963 and renovated in 1992, the Emerald Trade Center is a fourteen-story building that houses approximately 40 jewelry stores. It also has agent offices, cutters, processing facilities and services such as foreign exchange, brokerage and shipping. We visited The Best Emeralds offices where we saw three cutters cutting and pre-shaping emeralds ranging in weight from 3 to 20 cts. We were fortunate enough to be able to watch their master cutter saw a 700 carat block (Figure 26) and preshape it into countless stones, some weighing over 50 carats after cutting. In Bogotá, we also witnessed the legal export process firsthand as we prepared the collection of reference samples for shipment.

Street vendors were very busy outside the Emerald Trade Center on both days of our visit. The number of traders and trading volume appeared significantly higher than in 2005. Most trades involved local traders looking to fill orders, but there were also some foreign buyers. Mobile phones were an integral part of high street trading and traders were constantly on the phone to make offers to their suppliers or to check the interest of potential buyers.

In the Bogotá Free Trade Zone, we visit Colombia's Texas Transformadora (CTT), owned by Muzo Emerald Colombia, where the raw material from the MTC mine in Muzo is selected and cut. The blanks had many years of experience and the factory was divided into departments for further quality control, blind design and marking, sawing and preforming. Information about the origin of the tunnel and the date of excavation is carried on the cut stone. A certificate of origin and traceability is issued for each polished stone that documents the date, place and time of extraction and its passage through the manufacturing process. The report also includes photos of each step, the weight from raw stone to finished stone, and an indication of the backfill material (usually cedar oil). Since 2011, CTT has been ISO 9001:2008 certified by Bureau Veritas and accredited by the US ANSI-ASQ National Accreditation Board (ANAB) and the UK Accreditation Service (UKAS). The Bogotá factory also works with cutting shops in New York, Hong Kong and Paris.

As we documented mine operations and interviewed miners, management and owners, we saw how the industry evolved. Most of the changes we saw were also discussed during the Emerald Symposium in Bogotá.

According to the Ministry of Mines, 63% of all mining activities in Colombia are informal (Figure 27) and therefore the country does not receive the corresponding tax revenues (Ulloa, 2015). One of the government's top priorities in mining is organization and formalization. He adopted five pillars and a "three-door approach" to bring as many Guaqueros as possible into the legal mining system.

• Formalization: The government leverages public-private partnerships, regulation and traceability policies, while providing these miners with legal technical assistance and financial support through banks.

• Transformation: When informal mining takes place in areas where mining is illegal or unprofitable, the government works with other organizations to provide alternatives to work in other sectors.

• Law enforcement and prosecutions: If miners involved in illegal activities do not want to work in the official system or wish to convert to other industries, or if they are involved in criminal activities, the government will take strong legal action (Unninayar, 2015). .

All exploration and mining concessions are granted by the government through the National Mining Agency. Of Colombia's commercial mining activities, which include gold, platinum, coal, limestone and other materials, the 359 emerald concessions represent 3.6% of the total. (Granado, 2015). The Emerald Concessions cover approximately 88,000 hectares, less than 0.1% of Colombia's total land area. About 10% of them are currently in operation. Total mining royalty payments for 2012-2014 were $4.6 million. Although the overall size and revenue of the industry is small nationally, the impact on local mining communities is significant (Granados, 2015).

In 2015, 178 emerald traders were registered with RUCOM and in 2017 5,150 (G. Angarita, personal communication, 2017). The National Mining Service received 400 new applications for emerald mining concessions from national and international companies in 2015. Multinational companies such as MTC are investing in the industry or have shown interest in reviving it using modern technology and mining methods. These companies emphasized best business practices and corporate social responsibility as part of their branding campaigns, generating more dividends in these areas for national companies. This led Colombian companies to modernize and formalize to become more competitive. Colombia is one of 52 countries that have implemented the Extractive Industries Transparency Initiative (EITI), an international standard for mining governance and accountability.

When the author AL visited the country in 2005, many garimpeiros were not paid, but were allowed to take over part of the production, although this was not fully structured. Miners at many locations, including some of the largest operations, have found that going overboard can be a fatal mistake. In the official businesses we visited during this trip, all garibeiros reported receiving a salary, social security, and medical assistance in addition to participating in production. Gone is the sight of armed traders and miners in mining markets.

That doesn't mean there aren't more serious consequences. As with most colored gemstone producing countries, theft and pilferage still occur along the supply chain. In May 2015, over 1,000 people occupied the MTC mine for more than two days, pulling emeralds from a newly discovered case. The police eventually gained control, but only after a significant loss. The director of the MTC speculated that the invasion was carried out by a large, well-armed and organized criminal group (Burgess, 2015). At the time of our visit, a facility for military troops was being built near the mine.

The shift to larger, well-financed mining companies in Colombia and elsewhere is an inevitable and beneficial development. The balance that should exist between small miners, local communities and multinationals is often difficult to achieve. However, this balance is necessary to ensure a consistent and transparent supply chain, ethical practices and a positive industry image.

In 2015, Gemfields acquired a 70% stake in the Coscuez mine and 20,000 hectares in the municipalities of Muzo and Quipama for emerald mining (Gilbertson, 2015). Since then, Gemfields has pulled out of its Colombian operations to focus its efforts in Africa.

The Colombian government welcomes and supports foreign investment and participation in the sector (Angel, 2015), which brings formalization, tax revenue, transparency, best business practices, branding, environmental standards, modern methods and technologies, and employment. Many members of the Colombian emerald trade also welcome foreign investment, believing it will benefit their own development (U. Montenegro, personal communication, 2015). However, others believe that foreign involvement in the Colombian emerald industry should not be at the expense of local businesses, as it would not translate into jobs and profits. The new generation of leaders in the Colombian emerald industry wants to integrate the country into modern business while preserving local traditions (see Box A).

Multinational companies are making an investment that seems to guarantee increased production even as local mining operations are modernized. The Colombian emerald industry has already reaped significant benefits by developing a cutting industry that handles most of the national production and meets the highest international standards. In fact, Bogotá cutters are considered the world's experts in cutting Colombian emeralds. This cutting edge industry was built from within, something many African countries hope to achieve. A new generation of industry leaders is seeking to improve the branding of these emeralds and increase global market share.

With these opportunities come challenges. The image of Colombia as a country of violence and drugs is often conveyed in emerald green and must be overcome. The relationship between new foreign miners and local miners remains strained at times. The interests and rights of both parties must be protected and the formalization of the mining sector must be accompanied by a fair system of participation of independent miners. None of these challenges are insurmountable and the industry has the potential to reach unprecedented heights. For Colombian emeralds, the momentum of change seems irreversible.