gems, beryl, emerald, Colombia, Chivor

The history of the Chivor emerald mine in Colombia is rife with legend and adventure. The tale traces from early exploitation by indigenous people, to work by the Spanish in the sixteenth and seventeenth centuries, to 200 years of abandonment and jungle overgrowth. The story then picks up with rediscovery near the turn of the twentieth century by the Colombian mining engineer Francisco Restrepo using clues from a historical manuscript. Still the saga continued, with repeated shortages of investment funds driving multiple ownership changes and little progress toward mining the largely inaccessible deposit. The German gem merchant Fritz Klein, in cooperation with Restrepo, pursued limited mining activities with a small number of workers for a few months prior to the outbreak of World War I. After the war, the American company Colombian Emerald Syndicate, Ltd., took ownership, and mining operations resumed under the new leadership. Ownership changed yet again in the 1920s, followed by multiple cycles of expanding and shrinking mining activity, interrupted by completely unproductive periods.

gems, ruby, sapphire, opal, pearl, beryl, emerald, jewelry, general volume on gems

Both a reference book and an exhibition catalog, Gems unveils the fascinating world of minerals and gems through a dialogue between the prestigious collections of the Muséum national d'histoire naturelle in Paris and the great French jeweler Van Cleef & Arpels. The Muséum national d'histoire naturelle in Paris welcomes the exhibition Gems from September 16, 2020 to May 4, 2021.

corundum, quality.10, spinel, beryl, emerald, Mughal jewels, gems, Indian lapidary

Awakening a new understanding of the diverse tradition of Indian jewelry spanning four hundred years, the first edition of Beyond Extravagance in 2013 revealed for the first time the exceptional Al Thani Collection of the most important royal Indian jewels from the Mughal Empire to the British Raj to the twenty-first century. Exploring the centuries-long tradition of fine jewelry and art objects in India, to contemporary interpretations that continue to evolve today, this spectacular volume has been expanded and updated to highlight over 400 items in this magnificent collection. Key pieces include the carved jade wine cup of Emperor Jahangir, the Shah Jahan Dagger; inscribed imperial spinels belonging to emperors Akbar, Jahangir, and Shah Jahan; the Arcot II diamond and the Taj Mahal Emerald; and a ruby and pearl choker made by Cartier for the Maharaja of Patiala. Presenting a journey through the history of Indian jeweled objects, this splendid new edition features updated chapters by renowned jewelry experts including Vivienne Becker (The Impossible Collection of Jewelry); Katherine Prior (Maharajahs’ Jewels); Michael Spink, a specialist in Islamic and Indian art who lectures at the University of London; and Robert Skelton, one of the foremost authorities on Indian painting and fine objects. Edited by Amin Jaffer, senior curator of The Al Thani Collection, each section includes a detailed catalogue raisonné of featured pieces.

gems, beryl, emerald, history of emeralds in Colombia, Muzo, Coscuez, Chivor

A large proportion of the international trade in the world's finest emeralds is controlled by a community descended from Central Asian crypto-Jews. They were brought to the Islamic holy city of Mashad, in northeastern Iran, to serve as treasurers for the Khorosan Empire. In 1839 they were forced to convert en masse to Islam. They retained a Jewish identity in secret. They came to specialize in the international trade in high-value merchandise. A centuries-long history of discrimination impelled the members of this community to emigrate to Israel. From there, they went to Queens, New York. Members of this community began traveling to Colombia to purchase precious emeralds. Their experience in international, semi-licit trade, their access to credit through family connections, allowed them to prosper in the Colombian emerald trade. Members of this community still travel back and forth between Bogotá and New York's diamond district moving the world's finest emeralds. The geology and gemology of emeralds makes them unlike any other mineral commodity. The descendents of the central Asian crypto-Jews took advantage of a difficult historical conjuncture and came to dominate the international trade in this precious stone.

gems, beryl, emerald, Colombia, Afghanistan, Brazil, Russia, Mozambique, Madagascar, Zambia, Zimbabwe, India, geology, analytical, provenance, emerald worldwide

Although emerald deposits are relatively rare, they form in specific yet varied geological settings, and current classification models are often too restrictive, leading to confusion about the precise formation mechanisms of certain occurrences; emerald is essentially beryl containing sufficient concentrations of chromium and vanadium to produce its characteristic green hues, and its formation depends on conditions supplying both beryllium and chromium or vanadium—traditionally grouped into three types: desilicated pegmatite-related deposits formed by metasomatic fluid interaction with beryllium-rich pegmatites intruding Cr- or V-rich rocks; sedimentary deposits, responsible for much gem-quality emerald, formed by brine interaction with Cr/V-bearing sedimentary rocks along faults; and the rarer metamorphic-metasomatic deposits involving deep crustal fluids and metamorphosed shales, carbonates, and ultramafic rocks—with all three models requiring tectonic activity, which can transform one type into another through metamorphism and partial melting, thus blurring distinctions; to address the limitations, this paper proposes an enhanced classification system based on geological environment (magmatic or metamorphic), host-rock type, metamorphic grade, mineralization style, and fluid characteristics, accounting for multi-stage processes, beryllium remobilization, and using chemical, isotopic, and fluid inclusion studies to support genetic models, thereby categorizing emeralds into two main types: Type I (tectonic magmatic-related) with sub-types in (IA) mafic-ultramafic rocks (e.g. Brazil, Zambia, Russia), (IB) sedimentary rocks (e.g. China, Canada, Norway), and (IC) granitic rocks (e.g. Nigeria); and Type II (tectonic metamorphic-related) with sub-types in (IIA) mafic-ultramafic rocks (e.g. Brazil, Austria), (IIB) sedimentary rocks (e.g. Colombia, Canada, USA), (IIC) metamorphic rocks (e.g. China, Afghanistan, USA), and (IID) metamorphosed and remobilized or hidden intrusion-related deposits (e.g. Austria, Egypt, Australia, Pakistan), plus some unclassified occurrences.

gems, beryl, emerald, Colombia, Muzo, Chivor, Cosquez, Zambia, Afghanistan, Panjshir, Zimbabwe, Brazil, China, Ethiopia

The gem trade has grown to rely on gemological laboratories to provide origin determination services for emeralds and other fine colored stones. In the laboratory, this is mostly accomplished by careful observations of inclusion characteristics, spectroscopic analysis, and trace element profile measurements by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS). Inclusions and spectroscopy can often separate Colombian emeralds from other sources (although there is some overlap between Colombian, Afghan, and Chinese [Davdar] emeralds). For non-Colombian emeralds, trace element analysis by LA-ICP-MS is needed in addition to information from the stone’s inclusions. The relative chemical diversity of emeralds from worldwide deposits allows confidence in origin determination in most cases. This contribution outlines the methods and criteria used at GIA for geographic origin determination for emerald.

gems, corundum, gemology, field gemology, ruby, sapphire

GIA’s field gemology program was established in late 2008 to support research on geographic origin determination of colored gemstones. By building and maintaining an extensive collection of gem materials with known origins, GIA’s research scientists have been able to study and analyze rubies, sapphires, emeralds, and other gemstones using the best available reference samples. This has led to improved origin determination services while supporting numerous research and education projects. To date the collection has accumulated during more than 95 field expeditions on six continents and currently includes more than 22,000 samples. GIA’s field gemology efforts require a thorough understanding of the gem trade, including the evolution of gemstone deposits and the development of treatments. It is important to recognize potential new deposits and gemstone enhancement procedures immediately because they can change rapidly and leave a lasting impact on the trade. Field expeditions also involve documenting the mines and local conditions. These factors provide context for the gemstones and are becoming increasingly important in the eyes of the public.

gems, corundum, geology.11, beryl, emerald

The great challenge of geographic origin determination is to connect the properties and features of individual gems to the geology of their deposits. Similar geologic environments can produce gems with similar gemological properties, making it difficult to find unique identifiers. Over the last two decades, our knowledge of corundum and emerald deposit formation has improved significantly. The mineral deposits are classically separated into primary and secondary deposits. Primary corundum deposits are subdivided into two types based on their geological environment of formation: (1) magmatic and (2) metamorphic. Magmatic deposits include gem corundum in alkali basalts as in eastern Australia, and sapphire in lamprophyre and syenite as in Montana (United States) and Garba Tula (Kenya), respectively. Metamorphic deposits are divided into two subtypes (1) metamorphic deposits sensu stricto (in marble; mafic and ultramafic rocks, or M-UMR), and (2) metamorphicmetasomatic deposits characterized by high fluid-rock interaction and metasomatism (i.e., plumasite or desilicated pegmatites in M-UMR and marble, skarn deposits, and shear zone–related deposits in different substrata, mainly corundum-bearing Mg-Cr-biotite schist). Examples of the first subtype include the ruby deposits in marble from the Mogok Stone Tract or those in M-UMR from Montepuez (Mozambique) and Aappaluttoq (Greenland). The second subtype concerns the sapphire from Kashmir hosted by plumasites in M-UMR. Secondary corundum deposits (i.e., present-day placers) result from the erosion of primary corundum deposits. Here, corundum is found in the following types of deposits: eluvial (derived by in situ weathering or weathering plus gravitational movement), diluvial (scree or talus), colluvial (deposited at the base of slopes by rainwash, sheetwash, slow continuous downslope creep, or a combination of these processes), and alluvial (deposited by rivers). Today, most sapphires are produced from gem placers related to alkali basalts, as in eastern Australia or southern Vietnam, while placers in metamorphic environments, such as in Sri Lanka (Ratnapura, Elahera) and Madagascar (Ilakaka), produce the highest-quality sapphires. The colluvial Montepuez deposit in Mozambique provides a huge and stable supply of clean and very highquality rubies. Primary emerald deposits are subdivided into two types based on their geological environment of formation: (1) tectonic-magmatic-related (Type I) and (2) tectonic-metamorphic-related (Type II). Several subtypes are defined and especially Type IA, hosted in MUMR, which accounts for about 70% of worldwide production (Brazil, Zambia, Russia, and others). It is characterized by the intrusion of pegmatites or quartz veins in M-UMR accompanied by huge hydrothermal fluid circulation and metasomatism with the formation of emerald-bearing desilicated pegmatite (plumasite) and biotite schist. Type IB in sedimentary rocks (China, Canada, Norway, Kazakhstan, and Australia) and Type IC in granitic rocks (Nigeria) are of minor importance. The subtype Type IIA of metamorphic deposits is related to hydrothermal fluid circulation at high temperature, in thrust fault and/or shear zones within M-UMR of volcano-sedimentary series, such as at the Santa Terezinha de Goiás deposit in Brazil. The subtype Type IIB is showcased by the Colombian emerald deposits located in the Lower Cretaceous black shales of the Eastern Cordillera Basin. These are related to the circulation of hydrothermal basinal fluids in black shales, at 300–330°C, that dissolved evaporites in (1) thrust and tear faults for the deposits of the western emerald zone (Yacopi, Coscuez, Muzo, Peñas Blancas, Cunas, and La Pita mines) and (2) a regional evaporite level intercalated in the black shales or the deposits of the eastern emerald zone (Gachalá, Chivor, and Macanal mining districts). Secondary emerald deposits are unknown because emerald is too fragile to survive erosion and transport in rivers.

gems, jade, jadeite, fei cui, nephrite, Burma, China, Japan, ivory, ruby, sapphire, beryl, emerald, coral

In the nineteenth and twentieth centuries it was fashionable to collect 'curios', objects so named because they aroused 'curiosity'. Imaginatively decorated and made from different materials, some of which are still underappreciated, these exotic objects from China and Japan fascinated Westerners. They stimulated a fad for Asia, captivated art lovers, and had a profound influence on the graphic arts in Europe. This beguiling period kindled a passion for collecting in Alfred Baur (1865-1951) and for creation in Alfred Cartier (1841-1925) and his three sons, Louis (1875-1942), Pierre (1878-1964), and Jacques (1884-1941). While the pieces fashioned in Asian style by the Maison Cartier are generally known, their historical and cultural context is not, thus the idea arose of bringing these fine creations together with the collections of the Baur Foundation, Museum of Far Eastern Art, based in Geneva. As one leafs through the pages, Asia Imagined slowly becomes apparent, like a treasure hunt. Diamond-studded pagodas and pavilions, busy scholars beneath the starry sky, nacreous moonlight scenes, shimmering phoenixes, jade dragons, and multi-colured cherry blossom-like gems depict an imaginary land. The Cartier magic has its effect. Side-by-side with the creations of the Parisian jeweler, the imperial porcelains, lacquerware embellished with precious metals, embroidered silks, jades, colored enamels, netsuke, sword hilts, and prints belonging to the Baur Foundation give their version of the marvels of China and Japan and install a unique dialogue, offering an exceptional opportunity to view two of the world's most outstanding collections.

gems, ruby, sapphire, beryl, emerald, jade, nephrite, spinel, Mughal jewelry

Treasures from the Al Thani Collection was an exhibition of artworks from the Al Thani Collection that was held at the Palace Museum in Beijing in 2018. The exhibition featured a diverse selection of artworks from different cultures and time periods. The exhibition featured artworks from antiquity to the early modern period. The exhibition included manuscripts, miniatures, metalwork, textiles, and jewelry. The exhibition included works from different civilizations, such as Egypt, China, Maya, and Cycladic. Sheikh Hamad bin Abdullah Al Thani is a member of the Qatari royal family and a distinguished collector. The first volume of the set documents the exhibition “The Gems and Jewels of India”. It is split into different sections including: The Mughal Treasury; Dynastic Gem and Jewels; Objects of Jade and Rock Crystal; Objects in Gold and Enamel; Regalia and Jewelled Ornaments; Cartier and the Great European Jewellers, and, finally, Contemporary Creations. The second and third volumes both document a second exhibition, held in 2018, entitled “Masterpieces from a Royal Collection”. Volume II focuses on ‘The Ancient World’ and ‘The Wider World’. The former includes Egyptian, Greek and Roman, Mesopotamian and Iranian works as well as Central Asian treasures, whilst the latter has objects from China, Pre- Columbian Central and South America, Africa and the Pacific. Volume III is split more specifically into ‘The Islamic World’ and ‘The European World’. Each theme is further devided into sub sections which cover all aspects of art including Manuscripts, Miniatures, Metalwork and Textiles, or Medieval Reliquaries, Limoges Enamels, Renaissance Jewellery, Rock Crystal and Wunderkammer objects, Silver, Jewellery (Cartier, Melerio, Chaumet, Bolin) and 54 pieces by Fabergé.