Field Report

FIELD REPORT THE COLOMBIAN EMERALD INDUSTRY: WINDS OF CHANGE Darwin Fortaleché, Andrew Lucas, Jonathan Muyal, Tao Hsu, and Pedro Padua Figure 1. 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 for- mal system is challenging. Photo by Andrew Lucas. olombia is synonymous with fine emerald, and ernment ownership and regulation, criminal activity, production is believed to date back well over a and violence have affected production over the years, Cthousand years. Over the centuries the beautiful ver- the industry’s greatest opportunities may still be dant gemstone, which emerges from areas that are ahead. Multinational companies are investing heavily also a lush green, has been linked to violence and in Colombian emerald mining, which has led to mod- human exploitation. Nevertheless, the desire of the ernization. The government’s position on emerald Colombian people to mine for this treasure and strike mining has also improved dramatically in this period. it rich has endured, with enough dreams coming true Calls for transparency and traceability have led to to drive their passion. branding and a revamping of the industry’s image. The In recent years, industry changes have accelerated, loose system of independent miners (figure 1) is seeing perhaps more profoundly than ever before. While gov- 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 See end of article for About the Authors and Acknowledgments. met at the First International Emerald Symposium in GEMS & GEMOLOGY, Vol. 53, No. 3, pp. 332–358, http://dx.doi.org/10.5741/GEMS.53.3.332 Bogotá to interview industry leaders and government © 2017 Gemological Institute of America officials. Many topics involving industry change were 332 FIELD REPORT GEMS & GEMOLOGY FALL 2017 Figure 2. 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. discussed at the symposium. Afterward, the team Boyacá Province. Archaeologists estimate that natives traveled to Colombia’s major mines and visited deal- were mining and trading Colombian emeralds as early ers and cutters in Bogotá to document the current as 1000 BC (Sinkankas, 1981). When the Spanish ar- state of the mine-to-market industry. We were also rived, they quickly took over the mining areas and able to collect rough emerald samples for the GIA lab- forced the indigenous people into slavery, extracting oratory’s country-of-origin reference collection. emerald for European royalty and aristocrats (figure 2) as well as Mogul rulers in India. The inhumane treat- HISTORY ment of the natives led Philip III of Spain (r. 1598–1621) Volumes have been written about the history of to issue a decree protecting them, but the tribes had Colombian emeralds. Our history section is therefore already suffered greatly by then (Keller, 1981). a brief overview of a fascinating and well-documented Mines that had been Spanish royal property fell topic. under Colombian government control after independ- Before the arrival of the Spanish in 1499, emeralds ence in 1810. Still, many independent miners—called were mined by the indigenous people of what is today guaqueros—continued to dig for emerald. By 1979 FIELD REPORT GEMS & GEMOLOGY FALL 2017 333 CARIBBEAN PLATE magmatic-metasomatic occurrences, while about 28% was from sedimentary-metasomatic deposits and 7% Caribbean from metamorphic-metasomatic types (Giuliani et al., Sea ECC 2015). Colombia’s emerald deposits are the sedimentary-metasomatic type. COCOS Northwestern Colombia is at the intersection of PPLA TTE N three major tectonic domains: the South American plate in the east and south, the Caribbean plate in CCC ² WCWC the north, and the Cocos and Nazca oceanic plates Emerrrald in the west (figure 3). The Colombian Andes are the mining aarea most distinguishing surface features resulting from the interactions between the three domains through- NAZCA SOUTH PLATE AMERICAN out geological history. Since the end of the Creta- PLATE Bogggot á ceous period about 70 million years ago, the convergence of the Nazca-Cocos oceanic plate with COLOMBIA the South American continental plate has played the most important role in shaping the region’s topography (Colletta et al., 1990). 0 100 mi From the Tierra del Fuego archipelago to Ecuador, the Andes consist of a single narrow mountain belt, Figure 3. Regional map of the major tectonic domains but in Colombia the northernmost Andes split into and structural features of Colombian emerald zones. three branches to form a trident-shaped topographic WC = Western Cordillera, CC = Central Cordillera, feature (figure 3). These three mountain ranges are the EC = Eastern Cordillera. Reproduced from Mora et al. Western, Central, and Eastern Cordilleras; the last is (2008). also referred to as the Cordillera Oriental. The three cordilleras are geologically distinct and came into ex- istence at different times (Irving, 1975). The Western two companies, Tecminas in Muzo and Esmeracol Cordillera consists mainly of Upper Cretaceous ophi- S.A. in Coscuez, had begun privatized mining. Rela- olitic rocks, while the Central Cordillera is composed tions between the two groups became strained. Ele- of Precambrian and Paleozoic basement rocks in- ments of the Colombian drug cartels tried to infiltrate truded by Mesozoic plutons. The Eastern Cordillera the industry in the 1980s, leading to the Green War, is characterized by a thick folded Mesozoic and Ter- in which thousands lost their lives. A peace treaty tiary sedimentary sequence overlying the Precam- was signed in 1990, mediated by the Catholic brian and Paleozoic basements (Colletta et al., 1990). Church. Instrumental in the treaty was the legendary The convergence of the Nazca-Cocos plate with the Victor Carranza, known as the “Emerald Czar” and South American plate has been absorbed partly by the considered the most influential figure in the emerald subduction along the Colombian-Equatorian trench industry at that time (Angarita and Angarita, 2013). and partly by the uplift of the Eastern Cordillera. The last five years have seen more foreign invest- All Colombian emerald deposits are located in the ment and multinational companies entering the Eastern Cordillera. Today, the western zone of the Colombian mining industry, stronger efforts at for- Eastern Cordillera is defined by a series of west-vergent malization, greater transparency, stricter enforcement thrusts and the eastern zone by a group of east-vergent of traceability, less violence, and new branding efforts thrusts (figure 4). The whole mountain range is to create a marketable image for today’s consumer. bounded by the Magdalena River Valley to the west and the Llanos Basin to the east. During the Middle GEOLOGY Miocene (peak at approximately 15 million years As noted by Giuliani et al. (2015), emerald can form in ago), the active convergent plate movements gener- a variety of geological settings but is mainly found in ated a great amount of shortening in the Eastern three types of deposits: (1) magmatic-metasomatic, (2) Cordillera region and caused uplift. This scenario is sedimentary-metasomatic, and (3) metamorphic-meta- the geologically well-known Andean phase. Worth somatic. According to worldwide production data from noting is that the Colombian emeralds formed before 2005, about 65% of global production came from the Andean phase. 334 FIELD REPORT GEMS & GEMOLOGY FALL 2017 N Triassic-Jurassic EASTERN FLANK ² □ □ Paleozoic-Carboniferous 5° ■ Paleozoic-Devonian □ Andean basement Middle Magdalena Basin □ Guyana Shield basement Neogene WESTERN FLANK □ □ Paleogene Llanos Foreland Basin ■ Upper Cretaceous 0 □ Lower Cretaceous km 30 0 30 km Figure 4. Cross-section of the Eastern Cordillera. The thrust faults along the western and eastern zones together show a typical “flower structure” formed by the east-west shortening. Adapted from Mora et al. (2008). In Colombia, emeralds are recovered predomi- Previous research and field surveys defined two nantly from Early Cretaceous shales. The shales were belts of emerald deposits along the two boundaries some of the topmost infill of a marine foreland basin of the Eastern Cordillera (figure 5). The western belt of the Central Cordillera that began in the Jurassic includes deposits such as La Glorieta–Yacopi, Muzo, and matured in the Late Cretaceous. Later, the inver- Coscuez, La Pita, and Peñas Blancas; along the east- sion of this basin before and during the Andean phase ern belt are Gachalá, Chivor, and Macanal (Branquet generated the relatively high topography of the East- et al., 1999). The emerald mineralization is associ- ern Cordillera and some of the local structures for ated with hydrothermal fluid circulation and there- emerald crystallization (Colletta et al., 1990; Bran- fore highly controlled by the structural development quet et al., 1999). within each belt. In both belts, emerald is found Santander Massif N □ Tertiary ² □ Upper Cretaceous Sierra Lower Cretaceous Figure 5. Simplified ge- Nevada del Cocuy □ ological map of Colom- Triassic-Jurassic bia’s Eastern Cordillera □ Basement and plutons and the distribution of Peas Blancas major emerald deposits Emerald deposits Coscuez I along its western

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