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TRAPICHE EMERALDS EMERALD REPORT the Secrets of Trapiche Emeralds - Author John Le Parc/December 2016 2 | TRAPICHE EMERALDS - RESEARCH REPORT 2016

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TRAPICHE EMERALDS EMERALD REPORT the Secrets of Trapiche Emeralds - Author John Le Parc/December 2016 2 | TRAPICHE EMERALDS - RESEARCH REPORT 2016 TRAPICHE EMERALDS EMERALD REPORT The secrets of Trapiche Emeralds - Author John Le Parc/December 2016 2 | TRAPICHE EMERALDS - RESEARCH REPORT 2016 TRAPICHE EMERALD One of the rarest gems in the world The origin of the name What is a Trapiche Emerald, a Trapiche Trapiche stones attract and fascinate many Sapphire or any other Trapiche gem? The collectors and investors which subsequently word “Trapiche” was used by the Spanish increases the price for the best pieces. In this Conquistadors named after the gears used project, we will also look at the growing to crush sugar cane, due to it six branch presence of the Trapiche stone in fashion, characteristic. Any gem can be Trapiche, with design ideas and creations featuring the which means that any gem can present a Trapiche Emerald. geometrical figure appearing in the stone, as The discovery of the Trapiche Emerald is not a result of a high concentration in chemical recent. During the colonization in America, elements on certain locations of the stone. Spaniards began to report a curious gemstone presented by the Muzo Indians (an indigenous tribe located in the actual region of Boyaca, Colombia) when the first exchange of resources were made. Indeed, archaeologists believe that local tribes began to mine and trade emeralds as early as 1000 A.D. Brief History In 1897, the first contemporary report concerning this natural phenomenon from The Société Mineralogique de France (The Mineralogical Society of France) below is an extract from the article: 'A perfect example of a Colombian 'Mr E. Bertrand exposed a couple of curious emeralds; Trapiche Emerald those samples come from Muzo, New Granada (Region corresponding now to Colombia, Ecuador, Venezuela and Panama). They are formed with a pale green hexagon in the middle surrounded by other green zones parallel to In the case of the emerald, we can observe a this hexagon, giving rise to a six Branch formation.' hexagonal form caused by a higher concentration in chromium. These rays In 1970, a new report made by the resemble those resulting from asterism, but Mineralogical Society of America presented they remain stable in their positions in the an analysis of Chivor and Muzo, Colombia´s crystal, when either the crystal or the light trapiche emeralds (a thousand crystals were source is moved. This particularity makes the examined) by Nassau and Jackson,who found that the principal coloring agent was Trapiche Emerald one of the rarest gems in vanadium and that those specimens were the world. all monocrystalline. Since this report, mysteries surrounding this rare gem were more understood and resolved by geologist and gemologist. www.ieex.com.co 3 | TRAPICHE EMERALDS - RESEARCH REPORT 2016 Geology of the Trapiche Emerald Emeralds in general can be found in many Trapiche Emeralds occur in metamorphic localities such as South Africa, Zimbabwe, and hydrothermal deposits, which means Brazil, Pakistan, India, Australia, Austria, that they are formed when hot fluids, Mozambique,Tanzania, USA, Afghanistan, released by the crystallization of the Zambia and Colombia. In the case of the magma, penetrate cracks and pores of the Trapiche Emerald, the Mines of Peñas rocks in the Earth’s crust when surrounded blancas and Muzo (Colombia) were used to by heat and pressure. be known as the only producers in the world (according to the Mineralogical Society of America, Nassau and Jackson). Then other mines such as Galachà began to present veins of Trapiche. However, a recent discovery has been made in Madagascar. A greyish green beryl Trapiche of approximately 14 carats has been reported in the GIA’s Gems and Gemology publication. Minerals analyzed by Nassau & Jackson in 1970 www.ieex.com.co 4 | TRAPICHE EMERALDS - RESEARCH REPORT 2016 Geology of the Trapiche Emerald In Colombia, Emeralds are mined in a The deposits from the eastern belt are specific region called Boyaca. This region is contained in a limestone–black shale line located at the beginning of a long range of formation, which is overlain by siliceous mountains called The Andes Cordillera, black shales. In the Chivor mining district, forming three branches of middle size the host rocks compose shale sequences mountains and basins. Located in the that contain limestone lenses and gypsum Eastern Cordillera Basin, the Colombian beds, mesh and chevron textures, and emerald deposits consist of two belts. On limestone grading to black shales the western side we can find the mining intercalated with olistostromes districts of Muzo, Peñas Blancas, La Pita, (sedimentary deposit). Coscuez and Yacopi. On the eastern side are Chivor, Macanal, and Galachà. The deposits from the western belt are contained in the black shales and The Eastern Cordillera is a folded belt intercalated dolomitic limestones, pushing the Llanos Foreland Basin to the calcareous carbon-rich black shales, east and the Middle Magdalena Basin to the siliceous black shales, and mudstones. west. The sediments are characterized by a compound of beds of sandstones, black shale and limestone. Map of the Mines in the Region of Boyacà www.ieex.com.co 5 | TRAPICHE EMERALDS - RESEARCH REPORT 2016 On the western side, the deposits measure Concerning the Trapiche crystals, their about 100 meters across and display source used to be a mystery. Later on, numerous folds, and tear faults. At the Old geologists found out that veins of trapiche Mine (Muzo), thrusts are evidenced by the were located in black shale zone called presence of calcareous black shales over “Banco amarrillo” (yellow level in Spanish; siliceous black shales. yellow due to the pyrite main composition) bearing veins. The geological map of the All the tectonic contacts are marked by region indicates that Banco Amarillo was centimeter- to meter-thick hydrothermal breccias (rock made by broken fragments formed by the breccia zone, albitites, and cemented by matrix) called the emerald-Furthermore it is located under “cenicero” (ashtray in Spanish). These the Company building of the Muzo mine breccias outline the thrust planes, which are and corresponds to a coat of the calcareous associated with intense hydraulic fracturing black shale that overthrusts the siliceous due to overpressure. The breccias are black shale. More recently Trapiche stones metamorphic with calcareous black shales have been found in the shale close to larger and white albite. bodies of Cenicero. The mine at 'La Pita' www.ieex.com.co 6 | TRAPICHE EMERALDS - RESEARCH REPORT 2016 The structure of the crystal As we have seen in foundation Class, A nearly colourless beryl occurs between and Emerald is a gem variety of Beryl and has within the six trapezoidal prisms and also in a Hexagonal crystal system. It chemical the central prism, with opaque minerals composition is mainly made by Beryllium, observed on and between the beryl grains. aluminium and silicate: Be3Al2(SiO3)6. The An overgrowth is separated from the six green colour of emerald is caused by prisms by tiny patches of opaque inclusions. Chromium and/or Vanadium. Despite its particularity, the structure of the Trapiche Emerald is monocrystalline and not macle such as the diamond, or twinned as lamellar twinnings in corundum. Rough Trapiche emerald crystal Its rough form is characterized by aIts rough form is characterized by a central deep green hexagonal prismcentral deep green hexagonal prism growing toward one end along the C-axisgrowing toward one end along the C-axis and with no inclusions. Six prisms paralleland with no inclusions. Six prisms parallel to the C-axis are extended from the facesto the C-axis are extended from the faces of the central prism and contain opaqueof the central prism and contain opaque inclusions.inclusions. Sketch of a rough Trapiche mineral showing its hexagonal central core along the C-axis in cone surrounded by the six prisms www.ieex.com.co 7 | TRAPICE EMERALDS - RESEARCH REPORT 2016 Crystal formation Trapiche emerald is formed during a beryl As I have mentioned above, the mix of crystal’s growth. Black shale (albite) infill at albite and beryl form a eutectic system, the emerald crystal junction to form a six which is one of the biggest specificities of spokes star effect.. The crystallization of the Trapiche Emerald. A eutectic system is a Trapiche Emerald is processed in different mix of two pure bodies which melt and phases: solidify at constant temperature. During the fusion, it behaves like a unique pure First, the central, tapered core grows under body. An example of eutectic system is hydrothermal conditions (fluids supply). salted water. In winter, roads are treated Second, growth may slow by less fluids with salt in order for ice to create a eutectic supply or even stop for some time. Next, formation with salt and remain liquid at a growth conditions change again, and both very low temperature. emerald and albite are formed in eutectic. However, the hexagonal prism faces of the core crystal are able to maintain their uniform growth, producing pure emerald, while areas growing from the edges between prism faces are not, and are filled by albite. This results in six areas of clear emerald and six of principally albite and minor emerald. Consequently, the central core and the six surrounding sectors of a trapiche emerald comprise a single, non- twinned crystal.” Asterism on Sapphire The Trapiche Emerald became more attractive and interesting since it has been discovered that trapiche emeralds are not a case of asterism, as many have suggested. Indeed, those branches look like an asterism effect, but in this case they are static and don’t move. Asterism is an optical Trapiche Emerald, effect related to gems containing rutile inclusions that, interacting with light, create a loose image of a star on the gem’s surface. www.ieex.com.co 8 | TRAPICHE EMERALDS - RESEARCH REPORT 2016 The other specificity of the Trapiche Emerald is, as I mentioned before, its Macle diamond, monocrystalline structure.
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