Publication Year: 2014 Title: Distinguishing Between Natural and Synthetic Green Chrysoberyl Abstract: K. Schmetzer, M.S. Krzemnicki, T. Hainschwang, and H.-J. Bernhardt. “Natural and synthetic vanadium-bearing chrysoberyl,” Journal of Gemmology, Vol. 33, No. 7–8, 2013, pp. 223–238. These photos show natural chrysoberyl from Tanzania (left) and synthetic green chrysoberyl crystals manufactured by the Kyocera Corporation of Japan. Photos courtesy of Karl Schmetzer.

              Bright mint-green chrysoberyl emerged from Tunduru, Tanzania, in the mid-1990s. This material, which owes its color to V3+ substituting for Al3+ in the chrysoberyl lattice, does not exhibit the green-red color change of the alexandrite variety of chrysoberyl (colored by Cr3+). Prior to the introduction of these goods into the marketplace, manufacturers in both Japan and Russia demonstrated that vanadium-containing chrysoberyl could be grown using the Czochralski technique. Only after the popularity of natural mint-green chrysoberyl did the production of gem-quality synthetic material begin, however. That was when Kyocera of Japan (and to a much lesser extent the Russian company Tairus) developed V-bearing synthetic alexandrite to mimic the crystals coming from Tanzania.

Natural mint-green chrysoberyl, much of it extremely clean, is also found in Ilakaka, Madagascar; Sri Lanka; and Mogok, Myanmar. Prior to this study, there had been very little investigation into either natural or synthetic V-bearing chrysoberyl. The authors compare the optical characteristics and trace element composition of the Kyocera synthetic material with natural specimens from all four regions to help distinguish between the various sources. Additionally, they evaluate the impact of V3+, Cr3+, and Fe3+ on color and absorption characteristics.

The Kyocera synthetic chrysoberyl, most similar in appearance to the Tunduru material, almost exclusively contained the chromophore V3+ (approximately 0.1 wt.% V2O3), with little to no Ti4+, Cr3+, or Fe3+ present. Natural green chrysoberyl had much more variable amounts of these cations, with Tunduru specimens containing 0.04–0.30 wt.% V2O3, 0.004–0.040 wt.% Cr2O3, 0.001–0.110 wt.% TiO2, and 0.08- 0.32 wt.% Fe2O3. The Ilakaka material, some of which appeared more yellow than the Tunduru chrysoberyl, had similar levels of V2O3, was nearly Cr2O3 free, and had lower levels of TiO2. In some cases, the samples showed significantly more Fe2O3, with levels as high as 0.55 wt.%. Sri Lankan material, which was more yellowish green than the other studied samples, had substantially more Fe2O3 (0.47 – 0.90 wt.%), with generally less V2O3 and similar Cr2O3 contents as compared to Tunduru material. The Mogok chrysoberyl, which was an intense bluish green, had essentially no iron but high levels of both V2O3 and Cr2O3, at 0.38 and 0.24 wt.%, respectively. The Mogok material also demonstrates the strongest pleochroism, with observed colors ranging from grayish violet to yellowish green to intense blue-green. Additionally, gallium was detected in all of the natural chrysoberyl and none of the synthetics. Tin is also found in much of the natural green chrysoberyl but not in the synthetic form.

Spectroscopically, the positions of the absorption maxima and the intensity ratios for the V3+ absorption bands were found to be consistent between synthetic and natural material containing little to no Cr3+. Features attributable to Cr3+ and Fe3+ were detectable in the corresponding natural spectra. Finally, the authors show that with the proximity of the Cr3+ and V3+ bands in chrysoberyl, separate bands for the two cations are not visible. Instead, a shift of the ν1 band to shorter wavelengths was observed with increasing Cr3+ content. Visually, much of the material was inclusion free, but all natural samples contained growth patterns not observed in the Kyocera synthetics. @chapter:6


Publication Year: 2018 Title: Crowningshieldite: A New Mineral Abstract: Figure 1. Left: A diamond sample from the Letšeng mine in Lesotho that contains the newly recognized mineral crowningshieldite, in the area circled in red. Right: Electron microscopy reveals individual grains of crowningshieldite in a fine-grained mixture with other minerals. Photos by Evan M. Smith (left) and Fabrizio Nestola (right).
GIA, in collaboration with researchers at the University of Padova, recently discovered crowningshieldite (figure 1), a new mineral named in honor of G. Robert Crowningshield (1919–2006), a pioneering researcher at GIA for more than 50 years. His many landmark contributions included the detection of irradiated diamonds, the initial report on General Electric’s facet-quality synthetic diamonds, and the description of “padparadscha” sapphire’s orangy pink to pinkish orange color. Crowningshieldite is a nickel sulfide mineral with a hexagonal crystal structure and can be regarded as the high-temperature polymorph of the mineral millerite. Discovered as an altered inclusion in two diamonds from the Letšeng mine in Lesotho, it was accepted as a mineral on September 18, 2018, by the International Mineralogical Association. @chapter:20


Publication Year: 2021 Title: Honey Brown and Light Yellow Hydrogrossular: An Uncommon Jade Imitation Abstract: Figure 1. This light yellow carving (36 × 21 mm) and honey brown cabochon (15 × 12 mm) were identified as hydrogrossular. Photo by C. Kamemakanon; courtesy of Pachara Chonlakit.

Hydrogrossular or hydrogarnet is a translucent to opaque, water‐bearing calcium aluminum silicate garnet that commonly shows microcrystalline texture. It has a range of colors: brown, colorless, green, gray, pink, and yellow. The most popular is the shade of green known in the trade as “Transvaal jade” or “African jade.” Recently, the GIT-Gem Testing Laboratory (GIT-GTL) received two samples of hydrogrossular garnet for identification: the light yellow carved pendant (~70 ct, 36 × 21 mm) and the honey brown oval cabochon (8 ct, 15 × 12 mm) shown in figure 1. These are not typical colors used for jade imitations.

Figure 2. The microscopic observation of the honey brown hydrogrossular sample (left) revealed a fine-grained aggregate structure and color patches (white arrow), as compared with the coarse-grained aggregate structure of the brown jadeite sample (right). Oblique fiber-optic light. Photomicrographs by S. Promwongnan; field of view ~14 mm.
Standard gemological testing of the honey brown cabochon showed a specific gravity of ~3.66 and a refractive index of ~1.71, while those of the light yellow piece were undeterminable due to the nature of the mounting and carving. Nonetheless, both stones exhibited weak red fluorescence to long-wave UV and were inert to short-wave UV radiation, and displayed massive fine-grained aggregate structures with a translucent glassy appearance (figure 2, left), which was quite different from the coarse-grained aggregate structure of jadeite (figure 2, right).

Figure 3. Raman spectra of the honey brown and light yellow samples (blue and red lines, respectively) as compared to the reference spectrum of grossularite from the RRUFF database (green).
The identity was also confirmed by advanced testing. The Raman spectra of both samples showed dominant peaks at 374, 415, 548, 825, and 879 cm–1 and other smaller peaks at 246, 278, 508, 627, and 1005 cm–1 (figure 3) that matched perfectly with the spectrum of grossularite in the RRUFF reference database (R040065). Semi-quantitative chemical analyses of both stones revealed enriched contents of silica, calcium, and aluminum, which are closely consistent with grossularite, a calcium-aluminum garnet.

Figure 4. The infrared spectrum in reflection mode of the honey brown sample (blue line) exhibits characteristic reflectance peaks of hydrogrossular garnet at 616, 843, 866, and 954 cm–1, as compared with the spectrum of the hydrogrossular reference sample (purple line). The spectrum of the light yellow sample was not measured due to the nature of the carving.
The infrared spectrum of the honey brown cabochon sample, measured in reflection mode between 580–1400 cm–1, showed characteristic reflectance peaks at 616, 843, 866, and 954 cm–1 that are similar to the spectra of the hydrogrossular reference sample (figure 4) as well as green hydrogrossular (see Fall 2015 GNI, pp. 342–343). Note that the reflectance spectrum should be almost identical to the transmission spectrum of the sample, and the same features should be observed in both cases.

Figure 5. Infrared spectra by transmission mode of the honey brown and light yellow samples (blue and red lines, respectively) show very strong broad (water-related) absorption bands between ~3000–4000 cm–1 as compared with the spectra of a hydrogrossular reference sample (purple line) and grossular (tsavorite and hessonite) samples (green and black lines, respectively). The vertical dashed lines at 3598 and 3662 cm–1 mark water-related absorption bands of hydrogrossular (>5 wt.% H2O) based on Rossman and Aines (1991).
The infrared spectra of both samples, measured in transmission mode between 1000 and 5000 cm–1 and displayed in % transmittance, showed very strong broad absorption bands between ~3000–4000 cm–1 that are somewhat similar to the spectrum of our hydrogrossular reference sample (figure 5), and coincide with water-related absorption bands of hydrogrossular (>5 wt.% H2O) centered at 3598 and 3662 cm–1 (see G.R. Rossman and R.D. Aines, “The hydrous components in garnets: Grossular-hydrogrossular,” American Mineralogist, Vol. 76, No. 7-8, 1991, pp. 1153–1164). In comparison, our grossular (tsavorite and hessonite) samples reveal much narrower absorption bands between 3500–3700 cm–1 (figure 5). Thus, the presence of very strong broad (water-related) absorption bands has confirmed that both stones submitted for investigation were indeed hydrogrossular.
In summary, the gemological properties, Raman spectra, and chemical compositions of the light yellow and honey brown samples are consistent with those of grossular garnet. However, the infrared spectra showing characteristic transmission peaks of hydrogrossular at 616, 843, 866, and 954 cm–1 and very strong occurrence of structural water (i.e., significant OH replacing Si in tetrahedral sites) have confirmed that these two stones are indeed hydrogrossular rather than grossular garnet. It is worth noting that one of the materials commonly used to imitate jade is fine-grained aggregate hydrogrossular garnet, not single-crystal garnet. @chapter:37


Publication Year: 2015 Title: Synthetic Moissanite Melee in a Colored Diamond Bracelet Abstract: Figure 1. This fancy-color melee diamond bracelet contained two synthetic moissanites. Photo by Sood Oil (Judy) Chia.

A colored diamond bracelet submitted to the New York laboratory for identification (figure 1) contained 162 round brilliants ranging from 0.05 to 0.20 ct, with a color range from near-colorless to fancy yellow and brownish yellow. Melee-size diamonds below 0.20 ct are usually not screened for synthetics and imitations, and melee set into fine jewelry are very seldom tested due to limitations from the mounting. But because of recent concerns over fine diamond jewelry set with melee-size synthetics and imitations (see H. Kitawaki et al., “Identification of melee-size synthetic yellow diamonds in jewelry,” Fall 2008 G&G, pp. 202–213; Winter 2014 Lab Notes, pp. 293–294), we decided to conduct a full analysis on the mounted round brilliants in this bracelet.

Testing was first performed on the 60 near-colorless round brilliants with the DTC DiamondSure. Several samples were referred and sent for further testing using Raman spectroscopy. Of these, two round brilliants were suspected as imitation. Close examination under the optical microscope revealed obvious doubling on the facet junctions, a key identification feature for synthetic moissanites (K. Nassau et al., “Synthetic moissanite: A new diamond substitute,” Winter 1997 G&G, pp. 260–275). Further testing with Raman spectroscopy confirmed this identification with three peaks at 768, 789, and 966 cm–1 (figure 2).

Figure 2. Raman spectroscopy confirmed the identification of two colorless round brilliants as synthetic moissanite with peaks at 768, 789, and 966 cm–1.
FTIR spectroscopy performed on the other referred near-colorless and colored melee identified them as natural. One melee was found to be type IaB, while the others were type IaA.

This analysis showed that melee-sized diamond imitations are being mixed with natural diamond parcels and set into fine jewelry without proper disclosure. Therefore, proper identification by a gemological laboratory is an essential tool to maintaining the integrity of the industry. @chapter:32


Publication Year: 1995 Title: A Chart for the Separation of Natural and Synthetic Diamonds Abstract: A chart is provided that describes those gemological properties that are key to the separation of gem-quality yellow, blue, and near-colorless (to colorless) natural diamonds from synthetic diamonds. This format was designed to give jewelers and gemologists a ready reference to identify synthetic diamonds as they enter the jewelry trade. Magnification and luminescence are the most important testing techniques currently available to jewelers and gemologists. The most distinctive features of synthetic diamonds include color zoning, graining, metallic inclusions (often making the stone magnetic), and uneven ultraviolet fluorescence. @chapter:31


Publication Year: - Title: New 3-D Software Expands GIA’s Pearl Identification Capabilities Abstract: 3-D modeling software helps researchers visualize the internal structure of this pearl. Image by Emiko Yazawa/GIA.

	Pearls are one of nature’s most beautiful and intriguing gems. They glow with life and warmth, connecting us to the life of a gem like no other. Whether natural or cultured, pearls possess a mystique and allure all their own.

	For much of its history, GIA has been collecting and studying pearls from around the world. Its scientists have used a variety of tools and techniques to help identify the different types of pearls, most notably X-ray images. But in the past few years, real-time X-ray microradiography (RTX) and computed X-ray microtomography (μ-CT) have provided the most advanced means of revealing internal structure and drawing useful conclusions on pearls the Institute examines. These images help GIA technicians and scientists determine whether a pearl is natural, bead-cultured, non-bead cultured, and so on. The addition of X-ray fluorescence and chemical analysis using energy-dispersive X-ray fluorescence (EDXRF) helps separate those of freshwater origin from their saltwater counterparts.

	Some pearls remain an identification challenge for even the most well-equipped laboratories. Researchers sometimes find surprises hidden inside—a piece of shell or other object that is difficult to identify. Until recently, they were only able to see a two-dimensional view of the pearl’s internal structure, which limited their ability to resolve the gem’s entire structure.

These μ-CT images were processed by GIA researchers and gemologists using 3-D software to further analyze the pearls’ internal structure. Photo by Jian Xin (Jae) Liao/GIA.

	That’s where the latest technology can step in to help.

	GIA recently acquired software that expands its ability to probe the internal features of pearls. This powerful research tool makes it possible to virtually explore, manipulate, extract and reconstruct specific areas of a pearl for analysis. It also gives researchers the ability to enhance the existing μ-CT data collected to see the details more clearly.

	Three examples demonstrate the potential of this software. The first shows one half of a well-defined shell that caused the natural pearl’s formation. The second example is of a pearl examined in the GIA laboratory in Bangkok and described in a recent Gems & Gemology Lab Note. It clearly shows the form of the central radiating structure, as well as the extraction capabilities of the software. The third shows a challenging structure that the software helps define more clearly.

	EXAMPLE 1

	The images below are conventional 2-D μ-CT slices of a pearl with a strange internal structure. Researchers suspected it was a piece of shell, but the exact shape or structure of the shell was hard to visualize.

The modeling software extracted the internal structure of this pearl from hundreds of μ-CT slices and reconstructed its three-dimensional shape.

Specific internal structures in the pearl were selected to reconstruct its 3-D shape, as shown from a screenshot of the software. The top left image is the 3-D model, while the others are 2-D slice images.

The 3-D image of the shell within the pearl provides much more information than the original 2-D X-ray images. Images by Chunhui Zhou.

	See the video of the internal shell.

	3-D Model of Shell in Pearl

	This video shows 3-D imaging of a shell within a pearl.

	EXAMPLE 2

	This pearl contains a structure thought to be a tiny organism called a foraminifera.

These examples are known as star sands, marine protozoa that belong to the same order as foraminifera and once lived on the ocean floor. While not usually associated with pearl formation, foraminifera were recorded in pearls as early as 1980 (A.E. Farn, “Notes from the Laboratory,” The Journal of Gemmology, Vol. 17, No. 4, 1980, pp. 225–228). Image by Emiko Yazawa/GIA.

The 3-D software makes it possible to extract and reconstruct the internal features to further support our opinion. The bumpy, uneven surface strongly resembles the structure of a foraminifera. Image by Emiko Yazawa.

	See the video of the internal foraminifera.

	Foraminifera Structure in Pearl

	This video shows 3-D imaging of a foraminifera structure within a pearl.

EXAMPLE 3

	The software also has the potential to analyze other unusual structures within a pearl. The following example is a freshwater pearl with a large internal void, along with an associated white growth feature that is connected to the main solid portion. The 3-D model of the pearl after segmentation provides much more information on the overall shape and size of the void components. By observing the shape of the entire void, a clearer understanding of the pearl’s identity emerges. This gives researchers an opportunity to analyze the internal structure of both natural and cultured pearls in a way that wasn’t possible before.

Left: A 2-D μ-CT slice of a reportedly natural freshwater pearl shows unusual void and growth structures. Right: The 3-D model generated using the μ-CT slices shows the outer transparent area as the white growth structure, while the red area represents the black void component and the green area is the boundary between the white growth and the void structures. Image by Emiko Yazawa.

	GIA researchers continue to explore these fascinating internal structures as part of the Institute’s long-term research into the “Queen of Gems.” The new 3-D software is the latest tool at their disposal. Delving into these mysteries will further our understanding and support the research-based identification and evaluation of pearls. As GIA researchers master the capabilities of this powerful software tool, they can apply their experience to these more challenging pearls. @chapter:14


Publication Year: 2019 Title: Quarterly Crystal: Orpiment in Barite Abstract: Figure 1. Numerous bright yellow crystals dominate the interior of this 74.31 ct barite cluster from Nevada. Photo by Nathan Renfro.

The 74.31 ct crystal cluster of transparent to translucent colorless barite columns shown in figure 1 measures 37.89 × 20.83 × 15.27 mm. It plays host to numerous small yellow crystals and radial sprays, which together give the cluster a light yellow color. The barite specimen is from the Regent mine in the Rawhide District of Mineral County, Nevada. The Regent mine was known to produce barite crystals with yellow orpiment inclusions in the mid-1990s. The pure yellow bodycolor of these numerous inclusions suggested they might be orpiment. Laser Raman microspectrometry was able to confirm our suspicions. Focused energy-dispersive X-ray fluorescence (EDXRF) analysis was used in an attempt to examine the chemical makeup of the inclusions, since orpiment contains arsenic as a main constituent. The EDXRF analysis showed the presence of arsenic. Based on chemistry, we determined that the yellow inclusions shown in figure 2 are indeed the arsenic sulfide mineral orpiment.

Figure 2. A combination of Raman and EDXRF analysis identified the inclusions as orpiment, a yellow arsenic sulfide. Photomicrograph by Nathan Renfro; field of view 3.83 mm. @chapter:13


Publication Year: 2017 Title: New Ruby Miner in Mozambique Abstract: Figure 1. The washing process used by Mustang Resources is different from most jigs used for colored stone mining. Photo courtesy of Mustang Resources.

Mustang Resources LLC, a publicly listed Australian company, is developing a ruby mining operation in northern Mozambique. With the success of the colored stone mining giant Gemfields, Mozambique has secured its position in today’s global ruby market. Mustang’s concession is located about 8 km northwest of Gemfields’ Montepuez ruby mine. Both properties are located on the ruby mineralization belt in the Montepuez Complex, where ideal physical and chemical conditions favored the formation of gem-quality ruby. In between the two concessions there are some designated ruby-bearing areas where individual small-scale miners can legally work.

While the geology of the Mustang operation is generally similar to that of the Gemfields concession, the bulk sampling strategy and washing process are slightly different (figure 1). Currently, the miners focus on exploring and sampling the secondary deposits. They open pits of 20 × 5 meters or 20 × 7 meters and immediately refill the first pit before opening the adjacent ones; this way, no large pit is left open on the surface of the mining area. Mustang has been using scrubbers instead of log washers to break the clay bodies in the ore. A new customized scrubber system will soon be in place to optimize this process. Unlike the jig system applied by many colored gemstone mining operations around the world, the team uses a giant rotary pan to concentrate the heavy minerals, including ruby, through the centrifugal forces generated during rotation.

Since the team from Mustang started to develop the project in early 2016, the exploration, bulk sampling and ruby recovery have made significant progress. Christiaan Jordaan, the managing director of Mustang’s Montepuez ruby project, informed the authors that the washing plant had been successfully relocated and tuned to operate efficiently and that grading into parcels had begun (figure 2). The team has test marketed these rubies in the United States, where some large, significant stones will be cut by well-known cutters. Mustang will also test the ruby market in Asia and other parts of the world. Jordaan reassured the authors that Mustang will focus on improving quality of life in the mining community and promoting their ruby as an ethically mined product. Since the beginning of this ruby mining project, the company has hired and trained 70 local employees to work together with foreign experts.

Figure 2. Taking a cue from Gemfields, Mustang Resources grades rough rubies into
specific quality and size parcels. Photo by Andrew Lucas and Tao Hsu, courtesy of
Mustang Resources. @chapter:1


Publication Year: 2023 Title: Artisanal Diamond Mining: Addressing the Knowledge Gap Abstract: Figure 1. Artisanal mining in Liberia. Courtesy of Diamonds for Peace.
In the developed world, the word diamond immediately evokes the allure and sparkle of a polished brilliant. What does the word mean, however, for an artisanal diamond miner living in poverty?
Artisanal diamond mining accounts for 20% of global production and significantly impacts millions of lives in the developing world, particularly in Africa. “Artisanal” simply implies that the tools and equipment used by the miners are rudimentary. This type of mining is conducted predominantly by individuals, small groups, or families, who frequently migrate in search of the next deposit. The work is subsistence labor, and the miners typically sell to anyone willing to buy (often without the luxury of a legal transaction). Despite its numerous challenges, which also include smuggling and human rights abuses, artisanal mining is their principal form of income. But beyond the fact that diamonds can be exchanged for subsistence money, what do these miners know about them?
In many countries where artisanal mining is prevalent, miners often have an innate and comprehensive understanding of the material. For example, Sri Lankan gem miners can expertly locate and sort through the illam (gem gravel) and differentiate between the fine-quality and lesser-quality material. They have been doing this for thousands of years. But diamond mining is different, particularly in Africa, where the first known primary deposit was discovered less than 200 years ago. In the twentieth century, the system of grading based on the Four Cs (color, cut, clarity, and carat weight) established a framework for price setting in the diamond trade. This pricing system for polished material underlies the value of rough material and determines its selling price. Therefore, understanding the Four C s is vital to the effective trade of diamond rough.

Figure 2. Miners sorting through gem gravel. Courtesy of Diamonds for Peace.
However, the majority of artisanal miners in Africa do not yet have a strong working knowledge of rough diamond, placing them at a significant disadvantage when negotiating the price of rough with buyers. In 2022, the NGO Diamonds for Peace conducted basic training on rough diamond grading for Liberian miners (figures 1 and 2), a project funded by the World Bank and operating in collaboration with Empowerment Works Incorporated.
Liberia’s first major diamond deposit was discovered in 1957 along the Lofa River, close to the border of Sierra Leone to the north, which has much higher diamond production. Currently, figures stand at around 50,000 carats per annum. Production peaked at 600,000 carats annually in the 1970s (although most of that figure could be attributed to smuggled material coming in from bordering countries). Two civil wars, starting with a military coup in 1980, resulted in export sanctions imposed by the United Nations. Since 2007, when the country joined the Kimberley Process, diamond has been reestablished as an important mineral resource, particularly with the recent discovery of diamond-bearing kimberlites. These deposits have not been commercially exploited. Instead, the mining remains artisanal and the material is found primarily in alluvial placers along the Lofa River.
In pre-training interviews given to establish each miner’s level of knowledge, numerous misconceptions became evident. For instance, they valued a diamond based on carat weight alone, regardless of quality, color, and potential yield. They had also been told that colored diamonds have no value. Such diamond “myths” have disseminated over the past fifty years, and buyers are often quick to exploit the miners’ lack of knowledge.

Figure 3. A parcel of rough diamonds, collected over a month by a Liberian artisanal miner. The diamond indicated by the arrow weighs 0.80 ct. Photo by Beth West.
For artisanal diamond mining to benefit the future of Liberian communities, the diamonds need to be traded for a price that reflects their real-time value according to their potential polished price (figure 3). The diamonds must be fed into the supply chain correctly, and the economic gain needs to find its way back into these rural communities. This boomerang-back of benefit is no easy feat in West Africa.
Yet small steps toward progress can be made by adjusting the information asymmetry. These artisanal miners need to understand the material they are working with. At the very least, it will give them a little more cash in their pocket and a slightly more comfortable standard of living. Regardless of the big picture, a simple win on that level is easily achievable.
Knowledge—and the sharing of it—is the key to building a stronger and more equitable supply chain. It is one thing for the supply chain to be traceable, but quite another for it to be equitable and ethical. To level the playing field, each player must be equally empowered. One thing that allows for such empowerment is knowledge. It is a simple right.
Diamonds for Peace, in collaboration with the author, is currently working on a next-stage “train to teach” program for the miners. @chapter:38


Publication Year: 1993 Title: Winter 1993 Gem News International Abstract: Colored Stones
            Update on Colombian Emerald Mining
            Vietnamese Garnets
            Myanmar Mid-Year Emporium
            Update on Monghsu Ruby
            Ruby in Kyanite from India
            Rare Gemstones from Quebec
            Attractive Ornamental Marble
            Thai-Myanmar Jewelry Manufacturing Joint Venture
Enhancements
            Irradiated Phenomenal Quartz
Synthetics and Simulants
            Amber Simulant from India
            Artificial Glass with High R.I. and S.G.
            More on Vietnamese Deceptions
The 24th International Gemmological Conference
Diamonds
            Canada
            India
            Green-to-Blue Diamonds
            History of Diamond Cutting
Colored Stones and Organic Material
            Amphiboles
            Beryl
            Charoite
            Corundum
            Garnet
            Meteorites with Gems
            Natural Glass
            Opal
            Porcelaneous "Pearls"
            Quartz
Gemstone Enhancement
Synthetics
            Early Synthetics
            Russian Synthetics
            Douros Flux-Grown Synthetic Ruby
Instrumentation
Miscellaneous
            Early Collections
            Colored Stone Cutting

To view the full section, download the PDF above. @chapter:2


Publication Year: 2000 Title: Technological Development in the 1990s: Their Impact on Gemology Abstract: In the last decade, technology has improved how we synthesize, process, identify, and otherwise study gem materials. Significant trends include: the widespread availability of computerized communication; the application of synthesis techniques to gem treatments; the increased prominence of treated synthetics; the greater need for expensive instrumentation to solve gem problems in general, and the broader availability of small dedicated instruments to solve specific problems; and the adaptation of techniques from other sciences. Potentially applicable technology must be evaluated critically to assess its usefulness and appropriateness to solve a particular gemological problem. @chapter:23


Publication Year: 2018 Title: Update on Russian Demantoid Production Abstract: Figure 1. Russian demantoids are well known for their pure colors and remarkable inclusions. Photo by Kevin Schumacher.

Russian demantoids (figure 1) are renowned in the gem community for their pure, vivid colors and spectacular inclusions. Alexey Burlakov, founder of Tsarina Jewels, shared some insights on the current production of Russian demantoids and emeralds. Tsarina Jewels is based out of Bangkok and was co-founded with his father, Dr. Evgeny Burlakov, curator of the Ural Geological Museum in Yekaterinburg.

According to Burlakov, there are currently two mines in the Urals producing demantoid in commercial quantities: Korkodin and Poldnevaya. They are about 7 km apart, located in the same geological massif that also hosts numerous gold and platinum mineralizations. Although the two mines are very close to each other, the material is very different. The Korkodin mine is characterized by a darker color, often with a brownish tint that can be removed by heat treatment. Poldnevaya produces material of lighter, more “open” colors without the secondary brown. Because they are naturally a pure green, these demantoids do not require heating to optimize the color.

A third known deposit is Nizhny, located in the Tagil region about 200 km north of the other two mines. This was the original deposit where Russian demantoid was discovered, but it is currently inactive. The material from this mine typically has a lighter color with a slightly bluish tint, setting it apart from the other two.

Russian Demantoid Production
Alexey Burlakov of Tsarina Jewels gives insight into production of demantoid from two Russian deposits.
Russian demantoid comes in a wide range of colors, covering all shades of green. Much of the material has a brown color that can become dominant. The finest color is considered a pure, vibrant green with no secondary hues. It is estimated that around 80% of the Poldnevaya mine production has a secondary yellow color, while 15% is apple green and around 5% top vibrant green.

A typical feature of Russian demantoids is the horsetail inclusion, a radiating pattern of asbestos fibers. Fully developed horsetails are still rare. This inclusion has been found in demantoids from other localities as well, but none of these deposits match the importance of Russia’s.

The main markets for Russian demantoid are the United States, China, and France. The French market demands smaller melee-sized stones, while Chinese and U.S. customers opt for stones over 1 ct. Prices of Russian demantoid have increased, especially for larger sizes. This is due to the limited production. It is estimated that the Poldnevaya mine produces between 300 and 1,000 carats of gem-quality material per month. This means that only a few stones over 3 ct are produced on a yearly basis.

Other important gemstones from the Ural Mountains are emeralds and alexandrites. The Urals produced large volumes of emerald in the beginning of the 20th century. During the Soviet era, the mines were reopened for beryllium mining. In recent years, emerald mining has started again. New production and specimens have already reached the market. The Russian emeralds are generally lighter green but clean compared to other deposits. Alexandrite is not being mined, but a Russian government corporation is actively developing and expanding the alexandrite/emerald mines in the Urals. @chapter:0


Publication Year: 2013 Title: Diamond with Unusual Laser Manufacturing Remnant Abstract: It is common to see laser manufacturing remnants on diamonds, especially stones in blocked form where the cut is not finished. Cutters may use lasers to show where to cut, which features to remove, or the desired shape. The remnants usually appear as straight or sinusoidal lines along the areas to be cut or removed.
A 3.59 ct Fancy Light brownish greenish yellow diamond recently submitted to the Carlsbad laboratory for examination displayed an unusual laser feature.

Figure 1. The 0.9 mm diameter laser manufacturing remnant on this diamond showed an interesting pattern. Photo by Troy Ardon.
The table of the blocked heart shape showed a laser remnant with an interesting pattern that resembled a watch face (figure 1). Unlike the typically linear remnants, this feature was circular and located directly on the table. The cutter’s intentions for placing the 0.9 mm diameter circle on the table are unclear, but it makes for a striking pattern rarely seen on diamonds, especially finished stones. @chapter:31


Publication Year: - Title: Summer 2020 G&G Available Now Abstract: The Summer 2020 edition of Gems & Gemology concludes the fancy-color diamond series with a discussion on yellow and orange diamonds and wraps up the saga of the Chivor emerald mine in Colombia. The issue also explores a surface luminescence imaging technique to separate natural from laboratory-grown diamond, the use of fluorescence spectroscopy to identify pearls that have been optically whitened and brightened, the geographic origin determination of nephrite based on isotope ratios, and more.
Naturally Colored Yellow and Orange Gem Diamonds: The Nitrogen Factor
The lead article, by Christopher M. Breeding and co-authors, investigates the four major defect groups responsible for the color in most yellow and orange diamonds. They conclude their fancy-color diamond series by focusing on yellow diamonds, the most commonly encountered colored diamonds of all, and their much rarer orange relatives.
Separation of Natural from Laboratory-Grown Diamond Using Time-Gated Luminescence Imaging
De Beers Group Technology has developed a method to easily separate colorless and near-colorless natural and synthetic diamond using an expansion of the surface luminescence imaging employed by the DiamondView. Colin D. McGuinness and co-authors explain how blue delayed luminescence can be used as an identifier for more than 99% of natural type IIa and type Ia diamond. This improved imaging technique helps eliminate the need for time-consuming and expensive testing.
History of the Chivor Emerald Mine, Part II (1924-1970): Between Insolvency and Viability
Karl Schmetzer and co-authors bring a dramatic close to the Chivor emerald mine’s rich history with part two. This story resumes after the controlling company, the Colombian Emerald Syndicate, Ltd., succumbed to bankruptcy in 1923. The tale continues with countless twists and turns involving stock market speculation, insolvency, and ownership changes.
Optical Whitening and Brightening of Pearls: A Fluorescence Spectroscopy Study
Cultured pearls often undergo a bleaching process and maeshori treatment to improve their appearance. However, the pearl trade also employs chemical compounds known as optical brightening agents to enhance the appearance of these goods. Chunhui Zhou and co-authors explore the use of fluorescence spectroscopy to quickly and effectively separate optically brightened pearls from those that are untreated or have undergone routine bleaching.
Hydrogen and Oxygen Stable Isotope Ratios of Dolomite-Related Nephrite: Relevance for Its Geographic Origin and Geological Significance
Hydrogen and oxygen stable isotope ratios can be used to distinguish the four most important origins of dolomite-related nephrite. Kong Gao and co-authors compare ratio values in samples from Russia, South Korea, and two locations in China and discuss how these ratios are related to ore-forming fluids. Combined with unique gemological characteristics such as color, luster, and transparency from specific nephrite deposits, these isotope ratios can be used to determine geographic origin.
Lab Notes
GIA laboratory staff present their latest findings in the Lab Notes section, including quench-crackled dyed blue chalcedony resembling Larimar, an exceptional purple sapphire from Montana, and HPHT-processed CVD laboratory-grown diamonds with low color grades.
Micro-World
The Micro-World section, dedicated to the inner world of gemstones, features unusually shaped rutile crystal inclusions in Russian emerald, windmill inclusions in the rare mineral sphalerite, and crystalline pyrite inside a 466.27 ct rock crystal quartz.
Gem News International
Finally, GNI correspondents from around the world report on a possible new find of purplish pink diaspore, the impact of ivory bans on the fossil ivory trade, the design and cutting of the “Fragility of the Eternal” kunzite, “rhodatrolite” from Indonesia, and a field trip to Crater of Diamonds State Park in Arkansas. @chapter:35


Publication Year: 2004 Title: Summer 2004 Gem News International Abstract: Colored Stones and Organic Materials
            Amethyst from California
            Green Petrified Wood from Arizona
            A Unique Quartz Sculpture from Peru
            Scapolite from Mozambique
            Update on Tourmaline and Other Minerals from Warner Springs, California
Instruments and Techniques
            Recent U.S. Patents for Diamond Fingerprinting Methods
Synthetics and Simulants
            Colored Cubic Zirconia Buddha Carvings
            “Shell Pearls” with Tridacna Clam Shell Beads
            Fake Tanzanite Mineral Specimens
Conference Reports
            ICNDST-9
            GAC-MAC 2004
Exhibits
            Pearls at the Royal Ontario Museum
            Carnegie Gem & Mineral Show
Conferences
            5th European Conference on Mineralogy and Spectroscopy
            Gems of Pacific Continental Margins
            Diamond 2004
            ICAM 2004 in Brazil
            Hong Kong Jewellery & Watch Fair
            Rapaport International Diamond Conference 2004
            CGA Gemmology Conference 2004
            Pegmatites at GSA
            Antwerp Diamond Conference

To view the full section, download the PDF above. @chapter:7


Publication Year: - Title: Rose Quartz Care and Cleaning Abstract: Rose quartz is a durable gemstone. With proper care, it will provide a lifetime of jewelry-wearing enjoyment. - Photo by Robert Weldon, © GIA

                      Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with which one mineral can be scratched by another. But the Mohs scale is deceptive. The steps between the minerals are not evenly spaced. For example, diamond is only one number away, but it’s many times harder than gems in the corundum family. With a Mohs hardness of 7, rose quartz is a gem that can provide a lifetime of wearing pleasure.

	Rose quartz ranks 7 on the Mohs scale of hardness.
Stability
Rose quartz is generally stable when exposed to light and heat.

Cleaning
Warm, soapy water is always a safe method for cleaning rose quartz. Cleaning with ultrasonic and steam cleaners should be avoided.

Treatment
Rose quartz is occasionally treated with radiation to intensify its color. @chapter:23


Publication Year: 2016 Title: Spectral Characteristics of Pinctada Mazatlanica and Pinctada Margaritifera Pearl Oyster Species Abstract: Figure 1. These Pinctada mazatlanica shells were obtained from Mexico. Left: The shell has a rounded outline, with a nearly equal height and width. The exterior surface exhibits alternating yellowish brown and dark greenish gray colors, with whitish blotches fanning out from the center. Right: The interior view of the shell on the left alongside a smaller example showing a yellowish green nacreous rim with a distinct orient. Photos by Lhapsin Nillapat.
Pinctada margaritifera is a well-known mollusk species of the Indo-Pacific region that produces gray to black pearls. Cultured pearls from the mollusk are often referred to as “Tahitian” in the market. Both natural and cultured P. margaritifera pearls are noted for their characteristic UV-visible spectra. The typical reflectance feature at 700 nm is a key identification attribute for this species (K. Wada, “Spectral characteristics of pearls,” Gemmological Society of Japan, Vol. 10, No. 4, 1983, pp. 3–11, in Japanese).

Pinctada mazatlanica, the so-called Panamanian pearl oyster, is a species closely related with P. margaritifera. Although P. mazatlanica was originally classified as a subspecies of P. margaritifera (R.L. Cunha et al., “Evolutionary patterns in pearl oysters of the genus Pinctada (Bivalvia: Pteriidae),” Marine Biotechnology, Vol. 3, No. 2, 2011, pp. 181–192), in 1961, the taxonomy of the Pinctada genus was revised, and P. mazatlanica was listed as a distinct species due to different shell characteristics and geographical occurrence. P. mazatlanica is extensively distributed along the western coast of the Americas from Mexico to Peru and around the Galapagos Islands. It is considered a native pearl oyster species of the Gulf of California in Mexico and around the Archipelago de las Perlas in the Gulf of Panama (G.F. Kunz and C.H. Stevenson, The Book of the Pearl, The Century Co., New York, 1908, p. 69). The spectroscopic characteristics of this species were believed to be similar to P. margaritifera (Winter 2005 Lab Notes, p. 347), yet this author was unable to find any recorded spectra in the literature.

GIA’s Bangkok laboratory recently studied three P. mazatlanica shells from Mexico (two are shown in figure 1). These shells appeared to have morphology between P. maxima and P. margaritifera mollusks (P. C. Southgate and J.S. Lucas, The Pearl Oyster, Elsevier, Oxford, 2008, p. 60). The rounded outlines were similar to those of P. maxima; in each, the shell’s height was almost equal to the width. The color of the outer surfaces alternated from yellowish brown to dark greenish gray, with rays of whitish blotches fanning out from the center. The inner nacreous rims ranged from yellowish green to dark gray with visibly iridescent overtones resembling P. margaritifera. To investigate reflectance UV-visible spectral characteristics in the dark and light nacreous areas, three pieces were cut from one of the shells (figure 2).

Figure 2. The lip area of one P. mazatlanica shell was cut into three pieces to investigate
the reflectance spectral characteristics in the dark and light nacreous areas. Photo by
Lhapsin Nillapat.
The dark gray nacre of all the samples exhibited the same spectral pattern as those recorded from naturally colored gray to black nacre of P. margaritifera shells and pearls. The reflectance feature at 700 nm was consistently present in these samples, together with a uroporphyrin feature at 405 nm (figure 3). Uroporphyrin has been established as one type of pigmentation responsible for gray to black tones in some pearl oyster species (Y. Iwahashi and S. Akamatsu, “Porphyrin pigment in black-lip pearls and its application to pearl identification,” Fisheries Science, Vol. 60, No. 1, 1994, pp. 69–71). However, the feature at 495 nm that is often displayed in natural dark-colored nacre from P. margaritifera was not present in these samples, while the spectra collected in white to silver areas lacked the 405 and 700 nm characteristics. The spectra were relatively featureless, with no significant reflectance showing in the visible region. This was in keeping with results obtained from the white to silver nacre of P. maxima and P. margaritifera shells and pearls (S. Elen, “Identification of yellow cultured pearls from the black-lipped oyster Pinctada margaritifera,” Spring 2002 G&G, pp. 66–72).

Figure 3. UV-visible reflectance spectra of the darker gray nacre areas of all three
P. mazatlanica shell samples shown in figure 2 are similar to the spectrum from a
P. margaritifera pearl. All show a uroporphyrin feature at 405 nm and a feature at
700 nm, which is diagnostic of P. margaritifera. These spectra prove the similar
spectral characteristics between P. mazatlanica and P. margaritifera.
Further studies at GIA’s New York laboratory on P. mazatlanica shells from GIA’s Carlsbad collection confirmed these findings. Additionally, the yellow-green nacre close to the dark gray nacreous rim of the shell showed a broad trough from 330 to 460 nm. This consisted of features between 330 and 385 nm and between 385 and 460 nm. A clear feature at 700 nm was observed, but the one at 405 nm was not evident. The spectra are comparable with natural yellow P. margaritifera nacre samples (again, see Elen, 2002).

Photoluminescence (PL) spectra collected on the dark gray and yellow-green nacreous areas of all the samples showed bands at approximately 620, 650, and 680 nm. These same PL bands are observed in naturally colored nacre of P. margaritifera and Pteria sterna, as well as several colors of P. maxima nacre (S. Karampelas, “Spectral characteristics of natural-color saltwater cultured pearls from Pinctada maxima,” Fall 2012 G&G, pp. 193–197).

The reflectance and PL spectra from our samples prove the close relationship between P. mazatlanica and P. margaritifera. Pearls produced by these two black-lipped oyster species therefore share similar spectral characteristics. @chapter:14


Publication Year: 2022 Title: The Year of Mineralogy at the Perot Museum Abstract: Figure 1. The Year of Mineralogy at the Perot Museum of Nature and Science in Dallas features 10 cases filled with fascinating samples demonstrating the importance of the mineral world around us. Photo courtesy of the Perot Museum of Nature and Science.
2022 is the International Mineralogical Association’s designated year for celebrating the history, development, and role of mineralogy, with a goal of promoting public interest in mineral studies. The association aims to emphasize mineralogy’s critical role in technology and society and to highlight the future of mineralogy through the exploration of new and environmentally conscious methods for extracting the minerals used today. To help carry out this mission, the Perot Museum of Nature and Science in Dallas has created the Year of Mineralogy exhibit (figure 1) in the Lyda Hill Gems and Minerals Hall (https://www.perotmuseum.org/exhibits/halls/lyda-hill-gems-and-minerals-hall/).

Figure 2. This striking example of lapis lazuli, a rock composed of minerals including lazurite, pyrite, and calcite, is on display in the exhibit. From the Sar-e-Sang mine in the Kokcha River area of Badakhshan Province, Afghanistan. Photo courtesy of the Perot Museum of Nature and Science; specimen courtesy of Keith and Diane Brownlee.
With more than 5,700 minerals identified to date, and more added each year, there is no shortage of specimens to display. Each of the exhibit’s 10 cases educates visitors with spectacular examples to illustrate various mineral properties. The first case defines what a mineral is, showing specimens such as lapis lazuli and lazurite (figure 2). Chemical composition and crystal structure are explained in the second case, while the remainder are dedicated to the various properties of minerals, including hardness, tenacity, streak, luster (figure 3), and color.

Figure 3. The resinous appearance of this sphalerite specimen highlights the mineral property of luster. From the Picos de Europa Mountains, Asturias, Spain. Photo courtesy of the Perot Museum of Nature and Science; specimen courtesy of Gail and Jim Spann.
“By understanding mineral characteristics, like hardness, magnetism, and specific gravity, we are able to find solutions to many modern industrial problems and improve our overall well-being,” said Kimberly Vagner, director of gems and minerals at the Perot Museum.
On display until April 24, 2023, the exhibit is an opportunity for all ages to acquire a deeper understanding of the mineral world around us. Can’t make it to Dallas before April 24? Follow the museum’s Lyda Hill Gems and Minerals Hall on Instagram for posts highlighting some of the magnificent minerals on display. @chapter:3


Publication Year: - Title: Market Insight From a  Colored Gem Dealer Abstract: Bill VanceVance Gems

	Interview with Bill Vance, Vance Gems
Bill Vance, a colored gemstone dealer from Delaware, sounds the twin notes of apprehension at the increasing worldwide scarcity of high-quality colored-stone rough, and excitement at the investment opportunity this presents for the middle-range buyer. He forecasts rising demand and falling supply of gem-quality rough with no end in sight, due to mines becoming defunct and miners leaving the industry. What is selling at gem shows now, he says, is only the high end “best of the best.”

Middle-class buyers from India, China, and the Far East with disposable income are acquiring peridot, tourmaline, blue zircon, tanzanite, and other colored gemstones. Although this is driving prices higher, according to Mr. Vance it is not yet too late for buyers in this country to purchase, for example, a good-size 5- to 6-carat tanzanite for $400-$550 per carat. Such a gemstone will continue to gain in value, and thanks to currently low interest on savings and other investment instruments, is literally “better than money in the bank.”

As a GIA Graduate Gemologist himself, Vance is enthusiastic about the value of a rigorous gemological education, followed by plenty of exposure to material in the field. Since the public is increasingly knowledgeable about purchasing gems, it is imperative that gem-related businesses hire educated and ethical personnel. Credibility is everything, and those in the field with well-earned good reputations will be able to stay the course.
His advice to students?  “Always trust your instruments, never ever sight-identify, and don’t be afraid to say ‘I don’t know but I’ll find out for you.’” @chapter:28


Publication Year: 2022 Title: Red-Dyed Spodumene Imitating Ruby Abstract: Figure 1. A semitranslucent 5.72 ct red-dyed spodumene, presented as “red corundum.” Photo by Guy Borenstein.
A semitranslucent deep red oval faceted gem, measuring 13.88 × 9.08 × 5.88 mm and weighing 5.72 ct (figure 1), was recently submitted to Stuller Inc. by a client for a custom design. The stone was presented as “red corundum.” But initial quality control testing showed a biaxial refractive index of 1.659–1.678 with a birefringence of 0.019, which did not correspond with corundum.
Due to the incorrect identity, the stone was sent to Stuller’s gemological laboratory for further analysis. Standard gemological testing revealed a specific gravity of 3.237, with a moderate orange reaction to long-wave UV and a very weak reaction, along the fractures, to short-wave UV, typical of spodumene species. Further analysis, using a 532 nm Raman laser, also provided well-matched results for spodumene (LiAl(SiO3)2). Although the collected results clearly pointed to spodumene, the deep red color it displayed was questionable and required further investigation.

Figure 2. The unpolarized UV-Vis-NIR spectrum of the dyed spodumene shows a broad band centered at 561 nm due to the red dye. The band centered at 430 nm may be related to an intervalence charge transfer species between neighboring iron and manganese, while the band at 530 nm may be related to Mn3+.
Unpolarized ultraviolet/visible/near-infrared (UV-Vis-NIR) spectroscopy showed two merging broad bands centered at 530 and 561 nm (figure 2). The former is probably associated with the Mn3+ chromophore (H.U. Rehman et al., “An X-ray absorption near-edge structure (XANES) study on the oxidation state of chromophores in natural kunzite samples from Nuristan, Afghanistan,” Minerals, Vol. 10, No. 5, 2020, article no. 463), while the latter was previously reported as associated with red dyeing (K. Schmetzer et al., “Dyed natural corundum as a ruby imitation,” Summer 1992 G&G, pp. 112–115). A possibly iron- and manganese-related shoulder at 430 nm (R. Lu, “Color origin of lavender jadeite: An alternative approach,” Winter 2012 G&G, pp. 273–283) was also observed.

Figure 3. The FTIR spectrum of the dyed spodumene shows a series of peaks at 2954, 2924, 2872, and 2854 cm–1, associated with a typical universal paraffin oil.

Figure 4. Deep UV imaging of the spodumene’s surface showed strong luminescence of the dye within a cavity as well as surface-reaching fractures. Image by Guy Borenstein; field of view 6.25 mm.
Fourier-transform infrared (FTIR) spectroscopy revealed peaks at 2954, 2924, 2872, and 2854 cm–1 (figure 3), typical of a universal paraffin oil filler (M.L. Johnson et al., “On the identification of various emerald filling substances,” Summer 1999 G&G, pp. 82–107; L. Kiefert et al., “Identification of filler substances in emeralds by infrared and Raman spectroscopy,” Journal of Gemmology, Vol. 26, No. 8, 1999, pp. 501–520). Under deep UV illumination (<225 nm), the foreign filler in the surface-reaching fractures fluoresced strongly pink while the spodumene host rock was inert. The effect was especially prominent in a cavity near the girdle (figure 4).

Figure 5. Color concentration within surface-reaching fractures confirmed dye treatment in the spodumene. Photomicrograph by Guy Borenstein; field of view 2.66 mm.
Microscopic examination verified the FTIR, UV-Vis-NIR, and deep UV findings and revealed surface-reaching cleavages and fractures filled with a red foreign substance (figure 5), as well as natural inclusions.
The recorded results confirmed the gem as a red-dyed spodumene. Although spectroscopy identified some manganese, the lack of pink/red reaction under deep UV suggests a low concentration (Lu, 2012). Therefore, the authors assume that the starting material was either colorless or very pale pink spodumene.
Introducing red dye to intensify the color of corundum is a longstanding practice (Schmetzer et al., 1992). To the best of our knowledge, however, this is the first time a spodumene has been treated with a colored oil to imitate ruby. The result masks the true identity of the gem, and without gemological testing, an uneducated trader could misidentify it as a color-enhanced ruby. @chapter:10


Publication Year: 2013 Title: Jewels from Imperial St. Petersburg Abstract: Geared toward the jewelry historian, this thoroughly researched work is a window into the world of the Russian imperial Romanovs, starting with the reign of Empress Elizabeth (1741–1762), and ending with Nicholas II in 1917. The author details in chronological order the jewelry and objects d’art manufactured in St. Petersburg during this period. The book contains numerous photos of the jewels and family portraits from that era.

Reviewed by GIA Library Staff
Carlsbad, California @chapter:21


Publication Year: 1983 Title: The Rubies of Burma: A Review of the Mogok Stone Tract Abstract: For centuries, the Mogok Stone Tract of Burma has provided the world with its finest rubies. The mining district is situated about 700 km north of the capital city of Rangoon, with the rubies found principally in alluvial deposits weathering out of a crystalline limestone or marble. This article reviews the history of this famous locality, the geology of the area, and the mining methods that have predominated. Also covered is the gemology of these stones, including those inclusions that are characteristic of Burmese origin, and a discussion of famous rubies from Mogok. @chapter:37


Publication Year: 2023 Title: Spray of Columbite Crystals in Topaz Abstract: Bladed crystals of columbite radiate from a central point in colorless topaz. The mirror-like surfaces allow for reflections of neighboring blades, as seen in the top left crystal. Photomicrograph by Tyler Smith; field of view 2.90 mm.
A probable columbite inclusion in beryl was featured in a recent Quarterly Crystal, demonstrating the striking form these minerals can display (Spring 2023 G&G Micro-World, pp. 90–91). It was only fitting to follow up with a look at the same inclusion hosted by a different mineral.
The cluster of bladed columbite crystals in the figure above, identified via Raman spectroscopy, was found in an 8.91 ct colorless topaz. The thinner crystals allowed the brown bodycolor to show through, while the thicker, sword-like center crystal appeared black and opaque. Thin-film interference was observed between the host and inclusion when illuminated with oblique lighting, adding some welcome color to an otherwise featureless crystal face. While columbite has been previously described in topaz (Fall 2009 G&G Lab Notes, pp. 212–213; E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Volume 2, Opinio Publishers, Basel, Switzerland, 2005, pp. 263, 738), this is the most dramatic example observed by the author. @chapter:13


Publication Year: 2016 Title: Evidence of Focused Beam Irradiation in Treated Pink Diamond Abstract: Figure 1. This DiamondView image of the table of a pink diamond shows two distinct pink spots. Field of view approximately 5 mm. Image by Troy Ardon.

	A Fancy pink diamond, confirmed as natural-grown, was found to be type IIa and colored by
	NV– centers. As part of routine testing, DiamondView fluorescence images were collected to check for synthetic growth features. These images showed unusual patterning in the form of two pink spots near the edge of the table facet (figure 1). Both spots were approximately 0.9 × 0.7 mm, and the table facet was approximately 3.0 mm in diameter. The orange fluorescence throughout most of the table was likely due to NV0 centers, whereas the pink components were likely due to NV– centers.

	To further investigate the spatial distribution of the NV0/– centers, we acquired a photoluminescence (PL) image of the diamond’s table using a 532 nm laser. Figure 2 shows the distribution of the NV0 and NV– centers. The distribution of the NV centers confirms the presence of two spots on the table. Figure 3 shows the average PL spectra from inside one of the spots and the average PL spectra from the region outside the spots. Figures 2 and 3 demonstrate that the intensity of the NV centers was greater inside the spots than in the rest of the table. Inside the spots, the average peak area intensity of the NV0 center was approximately two times greater and the average peak area intensity of the NV– centers was approximately three times greater. The spots were comparable in both size and defect concentrations.

	Figure 2. Left: A PL map showing the peak area distribution of the NV0 center. Field of view is approximately 3 mm; scale is relative intensity. Right: A PL map showing the peak area distribution of the NV– center. Field of view is approximately 3 mm; scale is relative intensity.

	Figure 3. A comparison between average PL spectra from inside one of the spots and the area outside the spots. The y-axis scale is the same for both spectra, so it is apparent that the intensity inside the spot is higher for both NV0 and NV– centers.

	To determine the vertical distribution of the NV– center, a 500 µm PL depth profile was acquired through each spot. This is an automated process the instrument can perform in which a series of spectra are collected along a line spanning the diameter of the spot. The stage is then offset 5 µm in the vertical direction to focus farther into the diamond, and another series of spectra are collected. The process was repeated 100 times until the target depth of 500 µm was reached. This achieved a depth profile of NV– luminescence, indicating how deeply the irradiation beam had penetrated into the stone. One spot showed an average penetration depth of 100 µm and the other 50 µm. It is important to note that this is axial displacement, which in confocal microscopy is an approximation of the true depth of the illuminated feature. Nevertheless, this demonstrated the shallow penetration of the irradiation beam.

	The intensity variation in the NV centers strongly demonstrated that this diamond was HPHT annealed and isolated nitrogen was subsequently introduced due to disaggregation of the A-form nitrogen (pairs of nitrogen atoms) or B-form nitrogen (four nitrogen atoms around a vacancy). It also indicated that this diamond was irradiated by a focused electron beam with relatively low energy (≤1 MeV) prior to annealing. These multiple processes introduced high concentrations of NV centers into the localized shallow areas. Furthermore, an increase of electron donor defects at the incident beam area would lead to the observed patterned distribution of the NV– centers. The narrow, focused nature of the electron beam is responsible for the distribution of the defects into the two spots and therefore the reason why the pink spots are observed in the DiamondView image. The two spots may be the result of two separate beams in the irradiation setup. Alternatively, the second spot may be from an additional round of treatment designed to further enhance the color. It is also unusual for the treatment to be done through the table rather than on the culet. It is unknown what benefits the focused beam will have over wide-beam irradiation. @chapter:15


Publication Year: 2023 Title: Patchy Yellow Trigon Abstract: Trigons creating the impression of a thin and patchy “yellow skin” on a 0.98 ct rough diamond. Photomicrograph by Nicole Ahline; field of view 2.34 mm.
Occasionally, diamonds show irregularity in their color related to heterogeneous distribution of atomic-level defects. “Yellow-skin” diamonds are evidence of this. Seen in the figure above is the rough surface of a 0.98 ct diamond that shows a trigon with patchy yellow coloration. The yellow color is caused by isolated nitrogen that is confined to the outer surface of the rough stone, making it look like the rough diamond has a “yellow skin.”
Yellow diamonds colored by isolated nitrogen are known to have uniform to patchy or irregular color zoning (more information on naturally colored yellow and orange diamonds can be found in C.M. Breeding et al., “Naturally colored yellow and orange gem diamonds: The nitrogen factor,” Summer 2020 G&G, pp. 194–219). The color zoning (or lack of) correlates with the distribution of the nitrogen in the diamond’s crystal lattice as it grows. It is theorized that the “yellow skin” is from a subsequent growth event, making it younger than the colorless diamond it surrounds. @chapter:11


Publication Year: 1987 Title: The History and Gemology of Queen Conch "Pearls" Abstract: Conch "pearls" are calcareous concretions produced by the Queen conch mollusk, Strombus gigas, which is found in various areas of the Caribbean. Although conch"pearls" occur in a range of colors, the pink are usually the most desirable. "Pearls" over 10 ct are rare, but they have been observed as large as 45 ct. They sometimes exhibit a porcelain-like luster and an unusual characteristic called flame structure, which made pink conch "pearls" quite popular in jewelry at the turn of the last century. This article reviews the history of the conch "pearl," discusses S. gigas and its fisheries, and examines the gemological properties and other characteristics of this attractive material. @chapter:14


Publication Year: 2015 Title: Parisite in Colombian Quartz Abstract: These three crystals captured in Colombian rock crystal quartz host three crystal morphologies of the rare mineral parisite: bipyramidal, hexagonal tabular prism, and pyramidal forms. Photomicrograph by Jonathan Muyal; field of view 4.79 mm.

	The brownish rare earth carbonate parisite is known as an unusual Colombian mineral specimen, and as a diagnostic inclusion indicative of Colombian origin when observed in emeralds (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gems, Vol. 1, ABC Edition, Zurich, 1986, p. 252). This rare mineral has also been reported to occur in quartz from Muzo, Colombia (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Vol. 2, Opinio Verlag, Basel, Switzerland, 2005, p. 621).

	A particularly striking example of rock crystal quartz with numerous brown crystals of parisite was recently examined at GIA’s Carlsbad laboratory, where the inclusions’ identity was confirmed by Raman analysis. Interestingly, three of the most prominent parisite inclusions in this rock crystal quartz displayed multiple crystal habits: a well-formed bipyramid, a tabular hexagonal prism, and a pyramidal form. Due to their euhedral nature, these inclusions are presumed have formed simultaneously with their host quartz and are therefore termed syngenetic. Also present in the stone were numerous fluid inclusions and an iridescent interface on the bipyramidal crystal.

	This is the finest example of parisite as an inclusion in quartz that has been documented by GIA. @chapter:13


Publication Year: 2008 Title: Spring 2008 G&G Book Reviews Abstract: “Rings: Jewelry of Power, Love and Loyalty”
By Diana Scarisbrick, 384 pp., illus., publ. by Thames & Hudson Ltd. [www.thamesandhudsonusa.com], London, 2007. US$50.00

“The Emerald Book”
By Yogi Durlabhji, Shyamala Fernandes, and Ruchi Durlabhji, Eds., 143 pp., illus., publ. on behalf of the Jaipur Jewellery Show [info@jaipurjewelleryshow.org], Jaipur, India, 2007. Free

“Jewelry Savvy: What Every Jewelry Wearer Should Know”
By Cynthia A. Sliwa and Caroline Stanley, 224 pp., illus., publ. by Jewels on Jewels, Los Angeles, [www.jewelrysavvybook.com], 2007. US$19.99

“In Gold We Trust: Social Capital and Economic Change in the Italian Jewelry Towns”
By Dario Gaggio, 352 pp., publ. by Princeton University Press [www.press.princeton.edu], Princeton, NJ, 2007. US$39.50

“Safety Solutions”
63 pp., illus. with DVD, publ. by MJSA Press [www.mjsa.org/info_press.php], Providence, RI, 2007. $49.95 ($29.95 for DVD alone)

“Diamonds Are Waiting for You”
By James R. Holland, 63 pp., illus., publ. by A Bit of Boston Books [www.bitofboston.com], Boston, MA, 2007, $12.00

“Late Antique and Early Christian Gems”
By Jeffery Spier, 221 pp. with 154 black-and-white plates, publ. by Reichert Verlag, Wiesbaden, Germany, 2007, $297.00

To view the full section, download the PDF above. @chapter:21


Publication Year: 2019 Title: Tourmaline Inclusion in Russian Alexandrite Abstract: The longest inclusion in this photomicrograph of a Russian alexandrite was conclusively identified as tourmaline. This tourmaline inclusion exhibits a well-formed prismatic/rod-like crystal shape. Darkfield illumination. Photomicrograph by Jonathan Muyal; field of view 1.44 mm.

Alexandrite is the color-change variety of the mineral chrysoberyl. The most coveted alexandrite exhibits a luscious green to greenish blue color in daylight and a warm raspberry red in incandescent light. This phenomenal color change is caused by the presence of trace Cr3+ substituting for Al3+ in the chrysoberyl crystal structure. Alexandrite was originally found in the Ural Mountains of Russia in the early nineteenth century and was named in honor of Czar Alexander II.
GIA recently examined several Russian alexandrite rough specimens. These were reportedly from the Tokovaya mining area in the Ural Mountains, located a few kilometers away from the city of Yekaterinburg. Closer microscopic examination revealed a brown, transparent, well-formed prismatic crystal inclusion with triangular termination, indicating it might belong to the trigonal crystal system (see above).
The inclusion proved to be doubly refractive when viewed between crossed polarizers. Raman microspectrometry analysis conclusively identified the inclusion as tourmaline. In order to validate the Raman results and further identify the tourmaline species, laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) was used to obtain the chemistry of the inclusion (Z. Sun et al., “A new method for determining gem tourmaline species by LA-ICP-MS,” Spring 2019 G&G, pp. 2–17). It was classified as dravite, a sodium- and magnesium-rich tourmaline species. The trace element chemistry of the host alexandrite matched well with GIA’s Russian alexandrite chemistry reference data.
Inclusions in alexandrite from various localities have been reported (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Vol. 1, ABC Edition, Zurich, 1986, pp. 265–267; Vol. 3, Opinio Publishers, Basel, Switzerland, 2008, pp. 372–405). However, tourmaline in an alexandrite host is rare.
Alexandrite is traditionally popular for its beautiful color-change phenomenon rather than its inclusion scenes. The fine tourmaline crystal inclusion in this Russian alexandrite makes it an unusual collector’s gem specimen. @chapter:4


Publication Year: 2023 Title: Pinctada radiata Atypical Bead Cultured Pearls from the UAE Abstract: Figure 1. Two atypical bead cultured pearls recovered from Pinctada radiata mollusks from Abdulla Al Suwaidi’s farm in the UAE. Pearl A (left) weighs 0.87 ct, and pearl B (right) weighs 0.94 ct. Photo by Gaurav Bera.
Pearling is embedded in the culture and traditions of everyday life in the United Arab Emirates (UAE), especially in the trading center of Julfar. Abdulla Al Suwaidi, grandson of one of the last traditional pearl divers in the UAE, took on the challenge of reviving the country’s pearling industry. He succeeded in establishing the Suwaidi Pearl Farm in Al Rams, Ras Al Khaimah (RAK), in 2005. Suwaidi’s cultured pearl farm is recognized as the first of its kind in the Arabian (Persian) Gulf region.
GIA’s Mumbai laboratory recently examined a quantity of cultured pearls obtained from the farm. The parcel contained variously shaped white to cream-colored pearls. Examination by real-time microradiography (RTX) showed a variety of different internal structures including bead and non-bead cultured pearls, but two pearls in particular (figure 1) revealed very interesting structures and were confirmed to be samples from atypical “bead” culturing experiments conducted by the farm. Pearl A was light cream and near-round, weighing 0.87 ct and measuring 5.13 × 4.93 mm, while pearl B was cream and button shaped, weighing 0.94 ct and measuring 5.42 × 5.12 × 4.93 mm. When viewed under 40× magnification, both pearls exhibited a smooth surface and possessed typical nacreous overlapping aragonite platelets.

Figure 2. Top: RTX images in three directions of the non-bead cultured pearl used as a “bead” with a distinct demarcation and an organic tail-like feature in pearl A. Bottom: μ-CT scans of pearl A. The tail feature is indicated by a yellow arrow.

Figure 3. Top: RTX images in three directions of a natural pearl used as a “bead” with a clear demarcation and an organic tail-like feature in pearl B. Bottom: μ-CT scans of pearl B. The tail feature is indicated by a yellow arrow.
Additional RTX and X-ray computed microtomography (μ-CT) analyses were conducted to further study the internal structures. RTX imaging of pearl A revealed a non-bead cultured pearl used as a “bead” nucleus (figure 2). A light gray core surrounded by organic-rich concentric growth structures followed by finer growth arcs was visible. An obvious demarcation with a small organic tail-like feature just below the surface overgrown with cultured nacre was also apparent. The lack of growth arcs in the nacreous layers was due to rapid growth during the culturing process (“Atypical ‘beading’ in the production of cultured pearls from Australian Pinctada maxima,” GIA Research News, February 13, 2017). Similarly, pearl B revealed a natural pearl used as a “bead” nucleus (figure 3), with a very small but clearly visible dark gray core surrounded by faint growth arcs. As with pearl A, a distinct demarcation with organic-rich areas and a small organic tail-like feature were evident just below the surface overgrown with cultured nacre. X-ray computed microtomography analysis of both samples revealed clearer images of the demarcation between the “bead” pearls used as nuclei and the cultured nacre overgrowths.
Optical X-ray fluorescence examination did not show any fluorescence in either sample. Energy-dispersive X-ray fluorescence spectrometry revealed manganese levels below detection limits and strontium levels of 1130 ppm for pearl A and 1446 ppm for pearl B. The results from both testing methods were consistent with a saltwater growth environment. The ultraviolet/visible reflectance spectra collected for both pearls showed features around 435 and 460 nm and an additional weak band at 495 nm. These features are similar to spectral observations previously recorded for natural Pinctada radiata pearls (A. Al-Alawi et al., “Saltwater cultured pearls from Pinctada radiata in Abu Dhabi (United Arab Emirates),” Journal of Gemmology, Vol. 37, No. 2, 2020, pp. 164–179). Raman analysis using 514 nm laser excitation was carried out on the surfaces of both pearls, and a doublet at 704/705 cm–1 as well as a peak at 1085 cm–1, indicative of aragonite, were observed. Weak polyenic pigment-related peaks at 1130 and 1540 cm–1 were only observed for pearl B and were associated with its cream coloration. The photoluminescence spectra were also consistent with the Raman results and displayed high fluorescence together with the aragonite peaks, typical of most nacreous pearls.
Using lower-quality pearls (both nacreous and non-nacreous), gemstones, and other materials as “bead” nuclei has been a known practice for the last decade (“Chasing cultured pearls at SSEF: Cultured pearls using a natural pearl as a bead,” 2020, https://www.ssef.ch/chasing-cultured-pearls-at-ssef-cultured-pearls-using-a-natural-pearl-as-a-bead/). Although not seen on a regular basis, atypical “bead” cultured pearls (aBCPs) are encountered in laboratories from time to time and can be very challenging to separate from some natural pearls. This would be especially true of the two samples featured in this report: If either of them were drilled and mixed in strands with natural Gulf pearls, an experienced gemologist would find it difficult to separate them from the other pearls. The authors have encountered natural pearls with similar distinct boundaries. It should also be noted that the aBCPs produced at the Suwaidi farm are the result of successful experiments, and they are not commercially available at the time of this writing. The farm continues to conduct various experiments and aims to restore the UAE’s place in the global market by producing the finest Pinctada radiata cultured pearls available. @chapter:14


Publication Year: 1992 Title: Sapphires from Changle in Shandong Province, China Abstract: Sapphires were recently found in alluvial deposits and in situ in basaltic rocks near Wutu, Changle County, in central Shandong Province. The fact that significant amounts of sapphire have been found in situ at Changle makes it unique among sapphire deposits in basaltic terrains around the world. (Sapphires have been found in situ elsewhere, but never in such abundance in basalt.) Changle sapphires occur in a range of colors (dark blue, blue, greenish blue, and yellow), but they are predominantly dark blue. Fe, Ga, Ti, Co, and V are the most abundant trace elements present. The gemological properties of Changle sapphires are consistent with those from similar alkalic basalt environments. @chapter:6


Publication Year: - Title: Sapphires from the Gem Rush Bemainty area, Ambatondrazaka (Madagascar) Abstract: Sapphires of approximately 15 cts in size, reportedly from the gem rush near Ambatondrazaka, seen at KV Gems office in Bangkok in Dec 2016; stones courtesy KV Gems, Bangkok. Photo by Vincent Pardieu/GIA.

	New discoveries of fine quality blue sapphire sizes suitable for large fashioned gems are always welcomed by the gem trade. In the last decade and half, the island of Madagascar has emerged as a globally important source of gem quality corundum. However, the latest find of attractive large stones at Bemainty is problematic for the trade. Although it has produced more fine blue and padparadscha type sapphires than any other recent Malagasy deposit in just a few months, it is located deep inside a designated conservation area where mining is prohibited by the government.

	This report describes conditions at the mining sites, the mining methods used, and documents the gems seen at the mines and in local gem markets. It also provides a summary of the recent history of gem corundum mining in Madagascar along with regional and local geological context for the discovery.

	As a preliminary study, researchers from GIA’s Bangkok laboratory analyzed 38 representative Bemainty sapphire samples obtained from a reputable merchant in November 2016. They investigated gemological properties, inclusion scenes, spectroscopic features, and trace element chemical composition. Results from their study and field observations from the mining area appear in a new article titled “Sapphires from the gem rush Bemainty area, Ambatondrazaka (Madagascar).”

	This study indicates that the geographical origin of stones from this new locality will be challenging for gem labs to determine as the material ranges from geuda-type stones with low iron content similar to those from other Malagasy deposits and Sri Lanka, to gems with higher iron content resembling some blue sapphires from Myanmar or Tanzania.

	The new sapphire find at Bemainty is east of Ambatondrazaka and falls inside the Ankeniheny-Zahamena Corridor (CAZ), which was designated a protected area by the Malagasy government. As mining is prohibited within the CAZ, the arrival of thousands of people determined to mine challenges conservation efforts by the authorities. @chapter:37


Publication Year: - Title: Seeing Green: All About Emeralds Abstract: Emeralds are formed when chromium, vanadium, and iron are present in the mineral beryl. The varying presence of these three elements gives emerald its range of color. Chromium and vanadium make an intense green color. Iron gives the stone a bluish tint. Courtesy of Bill Larson, Palagems.com.

                      Want to see into the future? Be an eloquent speaker? Defeat spells and enchantments?
Such is the lore of the emerald.

The first known emerald mines were in Egypt, dating from at least 330 B.C. into the 1700s. Cleopatra was known to have a passion for emerald, and used it in her royal adornments. 16th-century Conquistadors discovered South American mines hidden by the Incas. A ready and exceptional supply of emeralds was suddenly available, and Europeans fell in love with the bewitchingly beautiful gemstone.

Some 500 years later, emeralds are still enchanting us. Emerald is the birthstone for the month of May because its color symbolizes the rebirth and renewal that comes with spring. Pantone named it the Color of the Year for 2013 because of the “luxury and elegance (it brings) to the palette.”

Emeralds are formed when chromium, vanadium, and iron are present in the mineral beryl. The varying presence of these three elements gives emerald its range of color. Chromium and vanadium make an intense green color. Iron gives the stone a bluish tint.

The most valuable emeralds are bluish-green to green and have a medium to medium-dark tone. Since emeralds typically form in six-sided prisms, they are naturally suited for, and often shaped into, the emerald cut.

Most emeralds have inclusions (internal clarity characteristics) and blemishes (surface clarity characteristics) that can be seen with the unaided eye. The size and types of inclusions greatly affect price: from $10 per carat for a small low-quality stone, to $50,000 per carat for an exceptionally clean stone.

So how hot are emeralds? Harry Winston sold a pair of circular clip earrings with 6.91 ct. and 7.32 ct. round emeralds for a cool $218,000 in November 2012. Brooke Astor’s 22.74 ct. emerald engagement ring went for $1.2 million at a recent Sotheby’s auction. @chapter:2


Publication Year: - Title: Lapis Lazuli Description Abstract: Lapis lazuli is an aggregate of several minerals. Lazurite grains provide its characteristic blue color, while golden flakes of pyrite can add attractive contrast.

                      Lapis lazuli is a rock, which means it’s an aggregate of several minerals. This ancient gem contains three minerals in varying amounts: lazurite, calcite, and pyrite. Sometimes, it also contains one or more of the following: diopside, amphibole, feldspar, and mica.

	Lapis lazuli is an aggregate of several minerals. Lazurite grains provide its characteristic color. The higher the percentage of lazurite grains in the aggregate, the darker the blue color. - John Koivula
Lapis frequently contains varying amounts of whitish calcite matrix—the host rock that surrounds the gem—or flecks or veins of glinting yellow pyrite, or both. The gem can also have a smoothly uniform bodycolor, free of visible pyrite and calcite.

	Calcite shows up as white flecks or streaks in the aggregate.

	The golden, metallic-looking spots in lapis are pyrite. - Robert Weldon, courtesy Gary Bowersox
Lapis is semitranslucent to opaque, with a waxy to vitreous luster. It has fair toughness, and its hardness ranges from 5 to 6 on the Mohs scale, depending on the mix of minerals.

Variously described as indigo, royal, midnight, or marine blue, lapis lazuli’s signature hue is slightly greenish blue to violetish blue, medium to dark in tone, and highly saturated. In its most-prized form, lapis lazuli has no visible calcite, although it might have gold-colored pyrite flecks. If the flecks are small and sprinkled attractively throughout the gem, their presence doesn’t necessarily lower lapis lazuli’s value. The lowest-quality lapis looks dull and green, the result of an excess of pyrite. Lapis with white calcite streaks is less valuable.

	The calcite matrix in this cabochon will lower its appeal to most buyers. - Robert Weldon
Although many people associate lapis with dark blue, it’s also found in other shades of blue, and even other hues. Its color can range from deep violet blue and royal blue to light blue to turquoise blue to a greenish blue. The combination of different minerals in the aggregate determines the color. For example, lazurite is responsible for producing royal blue lapis, while a mineral called afghanite creates a pale blue shade.

	This striking freeform carving displays a lovely shade of blue along with attractive golden pyrite accents. - Robert Weldon, courtesy Gary Bowersox
Worldwide, lapis is mined in several areas. The traditional source of the finest lapis lazuli is the same today as it was thousands of years ago—the mountains of Afghanistan. Other major sources are Chile and Lake Baikal in Siberia, Russia. Minor sources are Angola, Canada, Colorado (US), and Pakistan.

	Afghanistan is the world’s major source of lapis lazuli as well as the major source of the gem’s best color. - Dr. Edward J. Gubelin @chapter:0


Publication Year: - Title: Warm Up to Cocoa-Colored Gems Abstract: Chocolate has found its way to the necks, arms, hands, and bodices of fashion runway models.
According to experts at GIA (Gemological Institute of America), gemstones with warm, brown tones are heating up. And many of the world’s most influential designers in couture apparel and jewelry have built fashion menus around shades of brown – from the most delicate caramels and mochas to the darkest chocolates and coffees.

For the ultimate in russet glamour, think diamonds. Brown diamonds. A lightly tinted brown diamond, often marketed as a “champagne” diamond, or a darker “cognac” diamond, can accentuate a warm-toned wardrobe. The Institute, which grades many of the world’s diamonds, advises to always ask for a GIA Diamond Grading Report whenever purchasing a diamond.

Other brown and golden-colored gems that can heat up your wardrobe include sunstone, andalusite, citrine, tiger’s-eye, and amber. Fire opal is also a hot new front-runner in jewelry designs. Smoky quartz is sizzling too. Bold rings and pendants made of rough-cut crystals of rutilated quartz with gold and black needle-like inclusions remain popular.

Bronze-colored pearls can’t be left out either. From large Tahitians to fancy-shaped freshwaters, natural- and treated-color pearls come in a range of hues that complement sophisticated fall gem fashions.

The key to wearing the new browns in jewelry is to go for contrast: cognac diamonds juxtaposed with colorless diamonds; bronze pearls alternating with white pearls; and tiger’s-eye set in silver, just to name a few possibilities.

Other gems can create the same look, according to GIA’s gem mavens. Cat’s-eye, topaz, and brown zircon, and agate, even lesser-known gems like chrysoberyl and dravite, all provide the brownish shades favored by some designers. @chapter:21


Publication Year: 2016 Title: Rare Emerald from China and Pink Sapphire from Sri Lanka Abstract: Figure 1. This 5.06 ct emerald from China’s Yunnan province is one of the finest from this source. Photo by Robert Weldon/GIA, courtesy of 100% Natural Ltd.

	At the AGTA show, David Nassi of 100% Natural Ltd. (New York) showed the authors a 5.06 ct bright yellowish green emerald from China’s southwestern Yunnan province. The stone had some eye-visible inclusions, mainly fissures (figure 1). Other than a few tiny chips along the girdle, the cut gave the emerald a very elegant appearance. Mr. Nassi purchased the stone from a reliable Thai gem dealer who bought it from a Pakistani merchant who obtained it along the China-Pakistan border. Since Mr. Nassi is a cutter who deals with many antique jewelry pieces mounted with stones, he usually recuts stones before selling them. He kept this emerald “as is” due to the superb quality and size for this specific source. The stone was certified by the American Gemological Laboratory as without oil treatment, with China as the country of origin.

	China’s only economically viable emerald deposit is located in Malipo County in Yunnan province. The deposit was first discovered in the early 1990s but has never been extensively prospected or mined. Emerald specimens and crystals are extracted as the byproduct of the tungsten and tin deposit. Geologically, the ore body occurs in a core complex and is related to granitic intrusions in that area. Geochemical studies revealed that the trace element vanadium concentration is about one magnitude higher than that of chromium, indicating that V is the predominant chromophore in Yunnan emerald.

	The size and quality of this emerald are rare for Yunnan. Since the stones contain abundant fissures, most of the production is sold as mineral specimens or ornamental pieces (figure 2). A very small percentage can be faceted for jewelry. As the local government pays more attention to this emerald resource, new development and further exploration are expected.

Figure 2. Due to the fissures in Chinese emerald, stones are usually marketed as mineral specimens. This emerald crystal is still in the matrix. Courtesy of Yunnan Emerald Magazine.

	Mr. Nassi also showed us an intensely saturated 24.69 ct Sri Lankan pink sapphire (figure 3), from a necklace he had obtained from another estate jewelry dealer. Although the necklace itself was unattractive, Mr. Nassi immediately saw potential in the sapphire. He estimated the weight of the mounted stone and made an offer to buy the necklace. The stone, which was abraded with multiple scratches, lost two carats in its recutting but showed a dramatic improvement.

Figure 3. This 24.59 ct Sri Lankan pink sapphire was removed from an estate necklace and recut to bring out its full potential. Photo by Robert Weldon/GIA, courtesy of 100% Natural Ltd. @chapter:0


Publication Year: 2023 Title: The diamond industry of Israel. Abstract: Diamonds are classified as jewelry and precious gems, which are crucial commodities in trade between Thailand and Israel, ranking high in both exports and imports over the past several years. In the year 2565-2566 (Jan-May), Thailand imported these commodities predominantly from Israel, totaling 5,081 million baht, a 67% increase from 2564. Similarly, in 2566 (Jan-May), imports amounted to 2,289 million baht, marking a 29% increase from the same period.
Exports are equally significant. Jewelry and gems ranked second in Thailand's exports during 2565-2566 (Jan-May), with exports to Israel totaling 2,854 million baht in 2565, a 26% increase from 2564. In 2566 (Jan-May), exports reached 1,083 million baht, a 20% rise from the corresponding period.
Israel's diamond industry plays a crucial role in its economy, dating back nearly a century, well before the establishment of the State of Israel in 1948. It is noteworthy as a major source of income for the country and a leading export industry. Israel is known as the world's largest exporter of polished diamonds and a significant hub for raw diamond trade, generating substantial income and creating jobs for its citizens. This has had a profound positive impact on related sectors such as finance, high-tech diamond cutting technology, transportation, security systems, and banking services, all of which have seen significant development alongside the diamond industry.
Israel's diamond industry is characterized by its long and fascinating history, starting almost a hundred years ago, well before the establishment of the state of Israel in 1948. It is intriguing because it has been a major source of the country's significant income value, being one of Israel's leading export industries. Israel Diamond Exchange, the largest and most important diamond trading center globally, has been dubbed the 'World's Diamond Merchants'. It is one of the top five diamond exporters in the world, alongside India, the United States, Hong Kong, and Belgium. The prominence of India and the United States is unsurprising, given their large populations and abundant resources, and Belgium is well known as the capital of long-standing diamond trade. Hong Kong is known for its role as a trade representative of China and is a key port city. But for Israel, "Israel" is just a small country that does not even have its own diamond mine, but why has this country been able to export so many diamonds, because of the advantage points that have promoted the industry, with advanced diamond cutting and polishing technology that makes it possible to buy sell merchandise customs @chapter:38


Publication Year: 2015 Title: Dyed and Natural Green Jadeite Abstract: Figure 1. Left: In natural light, the green band in the lower right section of the jadeite specimen is caused by natural chromium, while the other green spots are the result of a dye treatment. Right: Long-wave UV light shows a strong fluorescence from the dyed areas, with little to no fluorescence from the natural green area. Photo by Robison McMurtry.

The most coveted jadeite stones possess a deep rich green color. Lower-quality jadeite specimens are often treated with acid bleaching, polymer impregnation, and dyes to obtain this sought-after hue (E. Fritsch et al., “Identification of bleached and polymer-impregnated jadeite,” Fall 1992 G&G, pp. 176–187). It is quite unusual to see stones with even a small amount of natural green color further altered with dyes. When this does happen, the natural properties of the untreated area can make it especially challenging to properly identify the stone as dyed.

Recently, the Carlsbad laboratory examined a carved jadeite specimen (figure 1). Standard gemological testing and Raman spectroscopy confirmed that the specimen was jadeite; infrared spectroscopy indicated the specimen had been polymer impregnated. Observation with a desktop spectroscope revealed lines at 630 and 655 nm, which are associated with chromium impurities in naturally colored green jadeite. Observation under long-wave UV light revealed strong green-yellow fluorescence from most green areas of the stone, but not from the area where Cr lines were seen in the spectroscope. The colorless portions of the stone were also inert to UV light. Strong fluorescence in jadeite is often indicative of either polymer impregnation or a dye treatment; however, fluorescence from polymers would be evenly distributed throughout the stone due to the nature of impregnation. The fact that this stone only fluoresced from the green areas was strong evidence of dyeing rather than impregnation.

Figure 2. Left: A close-up of the natural green area shows a smooth, diffused color texture. Photomicrograph by Jonathan Muyal; field of view 7.19 mm. Right: A close-up of a dyed area shows color concentrations in the thin gaps between the crystal grains of jadeite. Photomicrograph by Jonathan Muyal; field of view 3.57 mm.
Microscopic observation (figure 2) revealed concentrations of green color in the boundary gaps in between grains, typical of dyed jadeite. The green area without fluorescence possessed a smoother, more consistent green color, which is customary for natural jadeite. Absorption spectroscopy in the UV, visible, and near-IR range confirmed that the natural area contained an absorption band from 530 to 740 nm, punctuated by natural chromium peaks at 691 and 655 nm (figure 3). The dyed green areas contained a double band around 627 and 665 nm, which is typical of dyed green jadeite.

Figure 3. UV-Vis-NIR spectra of the jadeite in the 250–850 nm range showed chromium
lines at 655 and 691 nm in the natural green area and double broad bands around 627
and 665 nm in the dyed green area.
The proper treatment identification of jadeite is essential to the consumer’s confidence in this stone. Testing only a portion of this material might convince an observer that no dye had been applied. One must always expect the unexpected when attempting to determine treatments in any gemstone. @chapter:37


Publication Year: 2021 Title: Prida Tiasuwan (Pranda Jewelry Group) Abstract: COVID-19 safety measures in place at this Pranda facility include a disinfection tunnel at the entrance. Photo courtesy of Pranda Jewelry Public Company Limited.

Thailand enjoys a strong reputation for jewelry manufacturing, employing a highly skilled workforce in its many factories. Although it was the second nation with confirmed COVID-19 cases, Thailand remained relatively unaffected by the virus. The government quickly imposed strong measures such as remote work, curfews, and closure of places where people gather in great numbers. The action that arguably had the greatest impact was the closure of its international borders. The government tightly controlled travel to the country and enforced a strict 14-day quarantine for everyone who entered. Today, more people are allowed to enter, but the two-week quarantine is still mandatory.
The travel ban had a devastating impact on the region, which relies heavily on tourism and business travel, but it also left its mark on the local jewelry manufacturing scene. We spoke with Prida Tiasuwan, chairman of the Pranda Jewelry Group, about the situation in Thailand. He confirmed that the proactive measures taken by the government affected business in the first months of COVID, but this period did not last very long. By June 2020, business was returning, and a few months later demand was high, most likely because of the upcoming holiday season. This positive outlook continued with the arrival of vaccines in early 2021.
The Pranda facilities operated at reduced capacity during the Thai lockdown, which allowed the company to save costs due to reduced salaries for all staff and selected furloughs in April and May. Mr. Tiasuwan personally headed a task force consisting of department managers to ensure that all 2,200 staff remained safe and production could return to a normal pace as soon as possible.
By temporarily reducing capacity, they were able to improve working conditions for staff, including social distancing measures. Employees quickly adopted these new principles, and many of them were able to work from home. Since August 2020, the facilities have been back at full capacity with all required precautions, including a “Safe and Clean” campaign to remind everyone of the simple steps they can take to prevent the spread of the virus (see above).
Still, Pranda encountered issues with the supply of raw materials such as diamonds and certain colored stones. These are typically sourced or cut in countries such as India and China, where the impact on businesses was more severe during the first months of the pandemic. On the other end of the chain, physical retail was heavily impacted but was compensated by an increase in e-commerce.
The economic impact of the pandemic is also reflected in the demand for jewelry, according to Mr. Tiasuwan. The focus is on simple pieces in smaller sizes, with very few set stones or none at all. Customers have not been looking for fancy, colorful jewels during the pandemic, but Pranda expects this to change once the economic situation stabilizes. @chapter:27