Colombian emerald-producing areas such as Muzo have a long tradition of independent mining. The hope of finding the stone that will change their lives is a strong motivator for miners, but bringing them into a formal system is challenging. Photo by Andrew Lucas.
Colombia is synonymous with fine emerald, and production is believed to date back well over a thousand years. Over the centuries the beautiful verdant gemstone, which emerges from areas that are also a lush green, has been linked to violence and human exploitation. Nevertheless, the desire of the Colombian people to mine for this treasure and strike it rich has endured, with enough dreams coming true to drive their passion.
In recent years, industry changes have accelerated, perhaps more profoundly than ever before. While government ownership and regulation, criminal activity, and violence have affected production over the years, the industry’s greatest opportunities may still be ahead. Multinational companies are investing heavily in Colombian emerald mining, which has led to modernization. The government’s position on emerald mining has also improved dramatically in this period. Calls for transparency and traceability have led to branding and a revamping of the industry’s image. The loose system of independent miners (figure 1) is seeing efforts at formalization. These landmark changes are occurring at a time when most of the country’s emerald reserves have yet to be mined.
In October 2015, a joint GIA and Colombian team met at the First International Emerald Symposium in Bogotá to interview industry leaders and government officials. Many topics involving industry change were discussed at the symposium. Afterward, the team traveled to Colombia’s major mines and visited dealers and cutters in Bogotá to document the current state of the mine-to-market industry. We were also able to collect rough emerald samples for the GIA laboratory’s country-of-origin reference collection.
Volumes have been written about the history of Colombian emeralds. Our history section is therefore a brief overview of a fascinating and well-documented topic. Before the arrival of the Spanish in 1499, emeralds were mined by the indigenous people of what is today Boyacá Province. Archaeologists estimate that natives were mining and trading Colombian emeralds as early as 1000 BC (Sinkankas, 1981). When the Spanish arrived, they quickly took over the mining areas and forced the indigenous people into slavery, extracting emerald for European royalty and aristocrats (figure 2), as well as Mogul rulers in India. The inhumane treatment of the natives led Philip III of Spain (r. 1598–1621) to issue a decree protecting them, but the tribes had already suffered greatly by then (Keller, 1981).
Colombian emeralds were prized by the Spanish during their colonization of the New World. These stones and jewelry were lost at sea en route to Spain. Photo by Shane F. McClure.
Mines that had been Spanish royal property fell under Colombian government control after independence in 1810. Still, many independent miners—called guaqueros—continued to dig for emerald. By 1979 two companies, Tecminas in Muzo and Esmeracol S.A. in Coscuez, had begun privatized mining. Relations between the two groups became strained. Elements of the Colombian drug cartels tried to infiltrate the industry in the 1980s, leading to the Green War, in which thousands lost their lives. A peace treaty was signed in 1990, mediated by the Catholic Church. Instrumental in the treaty was the legendary Victor Carranza, known as the “Emerald Czar” and considered the most influential figure in the emerald industry at that time (Angarita and Angarita, 2013).
The last five years have seen more foreign investment and multinational companies entering the Colombian mining industry, stronger efforts at formalization, greater transparency, stricter enforcement of traceability, less violence, and new branding efforts to create a marketable image for today’s consumer.
As noted by Giuliani et al. (2015), emerald can form in a variety of geological settings but is mainly found in three types of deposits: (1) magmatic-metasomatic, (2) sedimentary-metasomatic, and (3) metamorphic-metasomatic. According to worldwide production data from 2005, about 65% of global production came from magmatic-metasomatic occurrences, while about 28% was from sedimentary-metasomatic deposits and 7% from metamorphic-metasomatic types (Giuliani et al., 2015). Colombia’s emerald deposits are the sedimentary-metasomatic type. Northwestern Colombia is at the intersection of three major tectonic domains: the South American plate in the east and south, the Caribbean plate in the north, and the Cocos and Nazca oceanic plates in the west (figure 3). The Colombian Andes are the most distinguishing surface features resulting from the interactions between the three domains throughout geological 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 continental plate has played the most important role in shaping the region’s topography (Colletta et al., 1990).
Regional map of the major tectonic domains and structural features of Colombian emerald zones. WC = Western Cordillera, CC = Central Cordillera, EC = Eastern Cordillera. Reproduced from Mora et al. (2008).
From the Tierra del Fuego archipelago to Ecuador, the Andes consist of a single narrow mountain belt, but in Colombia the northernmost Andes split into three branches to form a trident-shaped topographic feature (figure 3). These three mountain ranges are the Western, Central, and Eastern Cordilleras; the last is also referred to as the Cordillera Oriental. The three cordilleras are geologically distinct and came into existence at different times (Irving, 1975). The Western Cordillera consists mainly of Upper Cretaceous ophiolitic rocks, while the Central Cordillera is composed of Precambrian and Paleozoic basement rocks intruded by Mesozoic plutons. The Eastern Cordillera is characterized by a thick folded Mesozoic and Tertiary sedimentary sequence overlying the Precambrian and Paleozoic basements (Colletta et al., 1990). The convergence of the Nazca-Cocos plate with the South American plate has been absorbed partly by the subduction along the Colombian-Equatorian trench and partly by the uplift of the Eastern Cordillera.
All Colombian emerald deposits are located in the Eastern Cordillera. Today, the western zone of the Eastern Cordillera is defined by a series of west-vergent thrusts and the eastern zone by a group of east-vergent thrusts (figure 4). The whole mountain range is bounded by the Magdalena River Valley to the west and the Llanos Basin to the east. During the Middle Miocene (peak at approximately 15 million years ago), the active convergent plate movements generated a great amount of shortening in the Eastern Cordillera region and caused uplift. This scenario is the geologically well-known Andean phase. Worth noting is that the Colombian emeralds formed before the Andean phase.
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The 2015 expedition had three main purposes: to present at the International Emerald Symposium in Bogotá; to document the Colombian emerald mine-to-market industry, including the tremendous changes taking place; and to collect rough emerald samples for the GIA laboratory’s country-of-origin database reference collection. We also renewed relationships with the Colombian industry and created new ones. Andrew Lucas led the industry documentation project; Jonathan Muyal headed sample collection; and videographer Pedro Padua filmed the video interviews, industry activities, and the sample collection process. Field guide and Colombian gemologist Darwin Fortaleché handled logistics, provided guidance and insightful commentary, and recorded GPS coordinates of active tunnels, mine camps, and mine markets. Our resourceful driver, Miguel Gonzalez, who was also involved in emerald mining and trading, provided input and helped guide the expedition. We were able to document all the major mining operations in one trip through the lush green landscape of the Colombian Andes (figure 7). In Bogotá we observed the emerald cutting and trading sectors. More than 44 hours of video and 10,000 photos were captured, including in-depth interviews in the field with miners, cutters, traders, industry leaders, and government officials.
En route to mining areas along the Río Minero and Río Itoco in the Colombian Andes was some of the most beautiful terrain the authors had ever seen. Photo by Andrew Lucas.
For GIA’s reference collection we collected 1,243 rough emeralds weighing a total of 995 carats. Many of these specimens were obtained directly from miners in the field. Authors JM and AL also mined some deposits themselves, digging into the calcite veins with jackhammers and hand picks to retrieve the samples:
Two of the authors collected emerald directly from the deposits using hydraulic jackhammers to reach the emerald-bearing areas and then hand picks to remove the crystals from the host rock. Photos by Jonathan Muyal (left) and Andrew Lucas (right).
A sampling of the rough emeralds obtained for GIA’s country-of-origin reference collection. These samples, ranging from 0.445 to 6.397 ct, came from Coscuez. Photo by Kevin Schumacher.
We arrived in Bogotá on October 12, 2015, to attend the three-day symposium. There the GIA team gave presentations, finalized the expedition plan, and interviewed officials about recent changes. The following two days were spent documenting emerald cutting and trading in Bogotá and meeting with Colombian industry members. Early on October 18 we left Bogotá for Chivor. Our route took us first to the eastern belt mines of Chivor and Gachalá and then to the western belt mines of the Coscuez, Muzo, and La Pita areas. We stayed at mine camps and at hotels in nearby towns. The town of Muzo was used as a base to explore the active mines and markets in the western belt mines. The pace was brisk and usually involved driving at night so we could see the maximum number of mines and markets in our allotted time. By November 1, we were back in Bogotá to prepare the legal export of the emerald rough samples with licensed export brokers and board our return flights. Our expedition was short, given the goal of visiting all the important mining areas in Colombia and documenting cutting and trading, but in the end we were able to cover the entire mine-to-market industry.
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