gems, beryl, emerald, China, Davdar, inclusions

At the Davdar mine in Xinjiang, north-western China, emeralds are hosted mainly by carbonate, quartz–carbonate and quartz veins cutting metasedimentary rocks, and are associated with minerals such as hematite, dolomite, quartz, orthoclase and albite. Sixteen rough emeralds obtained during the authors’ visit to the mining area in 2019 were studied by standard gemmological techniques and various spectroscopic methods (FTIR, Raman, UV–Vis–NIR and EPR), as well as LA-ICP-MS chemical analysis. The analysed samples were mostly coloured by Cr, and showed a wide range of Fe, V, Mg and alkali contents, along with relatively low Cs, Rb and Sc. UV–Vis–NIR spectra showed features at 370 nm (Fe³⁺), 430 nm (Cr³⁺ with contributions from V³⁺ and possibly Fe³⁺), 580–630 nm (Cr³⁺ and V³⁺), 638 and 683 nm (Cr³⁺), and 850 nm (Fe²⁺ and possibly Fe²⁺–Fe³⁺ interactions). In addition, the more V-rich emeralds displayed a distinct V³⁺ absorption band at about 385–395 nm. Notably, the chemical composition of Davdar emeralds shows significant overlap with those from Panjshir, Afghanistan.

gems, archaeology, archaeogemology, Pakistan, Swat, beryl, emerald, 14C, Late protohistory, Early-historic phases, Bayesian analysis, Gandhara

In 2016 CIRCE and the ISMEO Italian Archaeological Mission in Pakistan launched a specific project specifically aimed at investigating a cultural phase that had not been previously explored, namely the transition phase between Late Bronze/Early Iron age (1200–800 BCE) and Early-Historic phases (c. BCE 500–80 AD) in the ancient Gandhara region. Current excavations of the key-site of Barikot (Bir-kot-ghwandai), supported by a substantial series of new radiocarbon dates, provide a new, very detailed chronological-cultural framework for the social evolution of ancient Swat after the late Bronze age. Thanks to the radiocarbon data published in this work, for the first time at Barikot it has been possible to discover or better define the Achaemenian, Graeco-Bactrian and Indo-Greek acculturational phases. Barikot is identified with the city of Bazira/Beira mentioned by Alexander’s historians’ and the siege of Alexander the Great, in 327 BCE, falling exactly in one of the identified archaeological frames.

gems, emerald, mineral inclusions, Malipo area of Yunnan Province, electron probe (EPMA), 祖母绿, 矿物包裹体, 云南麻栗坡, 电子探针

In this research, mineral inclusions in emeralds from Malipo, Yunnan Province, are studied by polarized microscope, electron probe(EPMA), and cathodoluminescence(CL). The results show that there are several kinds of mineral inclusions which can be considered as origin characteristics in emeralds from Malipo, Yunnan Province, such as black dravite, vanadium muscovite, zonal feldspar, arsenopyrite, magnesium biotite, scheelite. Both in pegmatite veins and shear zone veins, emeralds contain feldspar, albite, dravite, fluorite, emerald (beryl), biotite, sphene, apatite, pyrite, chlorite, epidote. Inclusions only appear in emeralds from pegmatite veins are muscovite, calcite, quartz, zircon, arsenopyrite, sphalerite, galena, diopside. Inclusion only appears in emeralds from shear zone veins is scheelite. This research on different inclusions in emeralds from pegmatite veins and shear zone veins is meaningful not only for emerald identification of origin, but also reveals the genetic type of Yunnan emeralds.

gems, metamorphism, carbonate platform, emerald, ruby, garnet, zoisite, lapis-lazuli, brines, fingerprints, salinity, molten salts, thermal reduction of sulphates, evaporites

The mineral and fluid inclusions trapped by gemstones during the metamorphism of carbonate platform successions are precious markers for the understanding of gem genesis. The nature and chemical composition of inclusions highlight the major contribution of evaporites through dissolution or fusion, depending on the temperature of formation from greenschist to granulite facies. The fluids are highly saline NaCl-brines circulating either in an open system in the greenschist facies (Colombian and Afghan emeralds) and with huge fluid-rock metasomatic interactions, or sulphurous fluids (ruby, garnet, tsavorite, zoisite, tanzanite, and lapis-lazuli) or molten salts formed in a closed system with a low fluid mobility (ruby in marble) in the conditions of the amphibolite to granulite facies. These chloride-fluoride-sulphate ± carbonate-rich fluids scavenged the metals essential for gem formation. At high temperature, the anions SO₄²⁻, NO₃⁻, BO₃³⁻, and F⁻ are powerful fluxes which lower the temperature of chloride- and fluoride-rich ionic liquids. They provided transport over a very short distance of aluminium (Al) and/or silica (SiO₂) and transition metals which are necessary for gem growth. In summary, the genetic models proposed for these high-value and ornamental gems underline the importance of the metamorphism of evaporites formed on continental carbonate shelves and emphasise the chemical power accompanying metamorphism at moderate to high temperatures of evaporite-rich and organic matter-rich protoliths to form gem minerals.

gems, beryl, emerald, China, Shaanxi, Zhen’an

Dai and colleagues investigate emerald-grade beryl from the Zhen’an tungsten–beryllium polymetallic deposit in Shaanxi Province using electron-probe microanalysis and micro-area X-ray diffraction. The study characterizes the chemical composition and crystal structure of the beryl and examines the relationship between compositional variations and its emerald-green coloration. Electron-probe analyses are used to determine major and minor elements and substitutions within the beryl structure, while micro-area X-ray diffraction provides structural information on selected portions of the material. The results are considered in relation to the mineralogical characteristics and formation of emerald-grade beryl within the Zhen’an polymetallic deposit, providing analytical data useful for understanding this Chinese emerald occurrence and its geological environment.

gems, jade, amphibole jade, nephrite, China

In this study, nephrite samples from Alamas and Karakash Rivers were collected. Also，serpentinite-related green nephrite samples were selected for comparison in colors. Methods such as electronic microprobe analysis and back-scattered electron images were employed to study the genesis and color-forming factors of nephrite. Based on whole-rock chemical analyses of nephrite obtained, the authors studied petrographic characteristics, mineral composition and color-forming factors. In this study, besides tremolite, associated minerals such as diopside, chlorite, actinolite，spinal, zircon, apatite, garnet, barite, pyrrhotine, graphite, calcite, and Fe(OH)₃ were found in nephrite. All samples have low concentrations of Cr, Ni (<100 ×10⁻⁶) and spots of Mg/(Mg +Fe²⁺) - Si, suggesting all these samples are dolomite related nephrite. According to the whole-rock analysis of nearly all data obtained, the data TFe₂O₃ = 0.33% ~1.42%, TFe₂O₃ = 0.43% ~ 0.96% and TFe₂O₃ = 0.77% ~ 3.97% were found in white, white-green and green nephrite, respectively. Also, values of Cr and Ni in these samples have low concentrations below 60 ×10⁻⁶ and 20 ×10⁻⁶ respectively. These chemical compositions suggest that the increasing content of TFe₂O₃ in crystal structures in tremolite leads to change of the colors in nephrite from white to green. Large amounts of graphite and veinlets of Fe(OH)₃ lead to the black color of nephrite. Although both serpentinite related and dolomite related nephrite samples have predominated tremolite, serpentinite related nephrite might have emerald color. In order to further study the coloring factors of Hetian nephrite, the authors collected samples of serpentinite-related nephrite in Canada for comparison. With serpentine related nephrite in Candia as an example, in addition to the amount of Fe, a large amount of Cr (1 400 ×10⁻⁶ ~ 5 100 ×10⁻⁶) was found in them. The emerald color of serpentinite-related nephrite is related to 0.01 ~ 0.03 a.p.f.u. of Cr in C site in tremolite. By contrast, there exists nearly no Cr in C site in tremolite in dolomite related nephrite. Based on the geological field observation and petrographic characteristics, the authors hold that the formation of Mg skarn has experienced metamorphism, metasomatism and sulfur stages and tremolite formed through the replacement at the expense of the dolomite marble, diopside and other minerals. Multiple replacement of coarse grained tremolite by fine-grained tremolite leads to the formation of nephrite.

gems, beryl, emerald, Colombia

In contrast to the murderous political violence I saw firsthand during my years emerald mining in Colombia, the passage of time has brought me a world embracing vision that tells me we are destined to experience humanity's unification throughout the planet. There is no doubt of the USA's capability to spearhead a golden age of mankind in the fullness of time. It is for us to decide if we want to be like the ocean's tides, unfailingly reliable, or as unpredictable as the ripple of breezes on the water's surface. The question is: Do we take the super highway to get there or the rocky road? We can perhaps find answers in the narrative I write about of the history of the Muzo Tribe of Colombia and my own life experiences. It's ultimately about helping to chart a course for humanity that is worthy of the noble potential with which our Creator has endowed us.

gems, ruby, sapphire, beryl, emerald, jade, gem identification

Hou draws on practical experience in the Chinese jewelry trade to provide a guide to buying, selling, identifying, and evaluating gems and jewelry in real-world transactions. Written from the perspective of an experienced dealer and collector, the book discusses the knowledge and judgment required when examining jewelry, assessing quality and value, negotiating purchases, and recognizing potential problems or misrepresentation. Through examples and accounts drawn from the marketplace, Hou emphasizes the importance of combining gemological knowledge with close observation, commercial experience, and an understanding of changing market conditions. The volume offers practical insight into the workings of the Chinese jewelry trade and the considerations involved in selecting, purchasing, and evaluating gem materials and finished jewelry.

gems, gemology,

A three-volume set, The Sisk Gemology Reference, Professional Edition, features over 1,000 pages and more than 2,000 photos, it will delight all, from those relatively new to the amazing world of gemstones to professional gemologists and jewelers long established in their careers. This comprehensive reference guide was the ultimate labor of love and a longtime mission of late Jewelry Television Co-Founder Jerry Sisk. His untimely passing left the task of completing the reference guide to our highly skilled team of gemologists and scientists. Volume 1, Prominent Gems, delves into the history, science, lore, sources, treatments and varieties (if applicable) of more than 100 well-known gems, including diamond, ruby, emerald, sapphire and tanzanite. Also included is an easy-to-comprehend study of gemstones and their properties. Volume 2, Noteworthy Gems, explores over 100 other rare and exotic gemstones, such as danburite, kyanite, pezzottaite and sphene. Volume 3, Gallery of Gems, is a pictorial compilation of incredible gemstones, jewelry and mineral specimens sure to leave you breathless as each page is turned. The Professional Edition is encased in a protective slipcase.

corundum, treatments.6, oiling in ruby, gems

Reports the examination of a 12.12 ct natural ruby whose inclusions and chemical composition were consistent with Myanmar origin, with no evidence of heat treatment. Microscopy revealed material within surface-reaching fractures, including flattened bubbles, whitish residues and patterns resembling dried oil in treated emeralds. Droplets formed at fracture openings under the warmth of fibre-optic illumination, while DiamondView imaging highlighted the filling’s luminescence. Infrared absorption confirmed an organic substance, with bands supporting identification as oil. The authors concluded that the ruby showed moderate transparency enhancement by fracture filling, probably with oil, documenting an unusual treatment in a large Myanmar ruby.