Publication Year: - Title: Fancy Color Diamond History and Lore Abstract: The 5.03-carat DeYoung Red is an exceptionally rare colored diamond. Chip Clark, - Courtesy Smithsonian Institution, National Museum of Natural History.

                      The world’s first diamond color-grading system dates back to sixth-century India. The system was based on the country’s ancient class structure. Members of different status levels, or castes, were permitted to own and wear only diamonds of a specific color. Thus, diamonds served as a badge of rank.

The priests and rulers, the Brahmins, were allowed to own diamonds that were “whitest of the conch, of the lotus, or of the rock crystal” (white to colorless). The landowners and warriors were assigned diamonds that were “the brown color of the eye of the hare.” The merchant class was allowed to own only diamonds that were the “pretty nuance of a petal of a kadl [flower]” (yellow). And members of the lower classes were assigned diamonds with “the sheen of a burnished sword” (gray or black). Kings, however, were free to possess diamonds of any color.

Diamond color-grading systems have evolved a lot since that time. Today, there are well-established methods for judging diamond color based on much more than a comparison to conch shells, rabbits’ eyes, and flower petals. And the only restrictions to owning different colors are based on availability and affordability.

While fancy color diamonds have traditionally been a small part of the diamond business, their popularity and availability have grown in the past several decades. In the 1980s the Argyle mine in Australia began marketing its brown stones under trade names like “Champagne” and “Cognac.” Argyle reached its goal of making the public more aware of fancy color diamonds and dropped its marketing campaign in the late 1990s. Today, the Argyle mine still produces brown diamonds, but it’s more famous as the world’s major source of rare pink diamonds.

	These rare pink and violet diamonds make up a tiny but important fraction of the Argyle mine’s production. - Courtesy Rio Tinto Diamonds
The most well-known historical and current sources of fancy color diamonds are India, South Africa, and Australia. Other diamond mine locations, including Brazil, Venezuela, Guyana, and Indonesia, also produce fancy color diamonds.

	Brownish diamonds, like these crystals and round brilliants, constitute the bulk of
	Argyle’s production. @chapter:29


Publication Year: - Title: Book Review: Making Steampunk Jewellery Abstract: By Nikki Druce, softcover, 128 pp., illus., publ. by The Crowood Press, Marlborough, Wiltshire, UK, 2016, US$29.95.

Steampunk is a genre of literature that has become a subcultural movement and has made its way into movies, comic books, music, art, and fashion. Its roots partially derive from the books of H.G. Wells and Jules Verne as a Victorian take on futurism, a world where steam-powered inventions are at the cutting edge of technology. The term “steampunk” was said to have been coined by author K. W. Jeter in the mid-1980s, and the movement gained prominence in the early 1990s. There are subgenres to steampunk, including clockpunk, boilerpunk, and decopunk. Each subgenre draws inspiration from different eras and social classes and, in turn, influences related literature and fashion. While some genres are darker and gothic in tone (dieselpunk), and others are more ethereal and inspired by fairy tales (dreampunk), the predominant steampunk fashion style is based on clothing from the Victorian era with retro-futuristic embellishments and accessories. Certain style elements are common to many of the subgenres: gears, cogs, goggles, watch parts, and ray guns, but there are no hard and fast rules for how one should dress as a steampunk. It is a fantasy world, after all.

Nikki Druce, a London-based designer and self-described “maker” of steampunk-inspired jewelry and owner of an online shop called “Devine Delinquents,” wrote Making Steampunk Jewellery for jewelry-making novices and for newer aficionados of steampunk. Druce is a self-taught jewelry maker who started making pieces for her own adornment; what started out as a hobby turned into a full-fledged business. The resulting jewelry and accessories were well-received and with this book, she shares her experience and skills to instruct readers on how to create their own pieces.

The book is organized into nine chapters, beginning with basic information about steampunk, the equipment and materials needed to create jewelry, and design inspirations. It then breaks out into sections with categories of more than 25 projects: necklaces, brooches/pins and rings, headgear, and other accessories. One fun and easy project is the ray gun necklace, which requires a small squirt gun, some acrylic paint, jewelry findings, and gears or watch parts.  Each project (or tutorial, as Druce calls them) is pretty straightforward, with step-by-step instructions for creating fairly simple pieces. She encourages readers to use the tutorials as starting points to build on their own creativity. At the beginning of each project, she has a photo of the finished piece; she also lists the materials and tools needed with accompanying photos. Each step also has its own accompanying photo. Although most of the projects are accessories worn by women, Druce does include a chapter on men’s steampunk projects, titled “The Captain of the Airship.” A wardrobe staple of the well-dressed steampunk gent is a top hat. One of the projects in this section is a top hat band that can add versatility to the hat. With elastic headbands, ribbon, felt, feathers, and a few decorative items like watch parts or gears, you can easily create several different hatbands to change the look. Another project for men is the jabot, a detachable decorative item of clothing that attaches to the front of a shirt. It has layers of fabric in waves and is usually decorated with a cameo, beads, or lace. This project requires a little more effort, but adds a touch of elegance to an outfit.

In the final chapter, the author provides advice on how to put together a complete outfit without spending a lot of money. Upcycling, taking old clothing and repurposing it to make something better than the original, is one way to save money. Druce also writes about commonly used fabrics, hair styling tips, and adding corsets, harnesses and bustles to create a costume with a look of authenticity.

In the back of the book, Druce provides further information on resources that may be of interest to further your knowledge of steampunk and a list of suppliers for steampunk items and clothing. Most of the suppliers listed seem to be based in the United Kingdom.

This book is well-organized, easy to follow, and nicely illustrated throughout, with photos of models in steampunk attire wearing the finished accessories. The projects require just a few basic tools, inexpensive supplies, and minimal crafting skills. It is a good book to aid someone through an initial foray into the world of steampunk. @chapter:16


Publication Year: - Title: Summer 2022 G&G Available Now Abstract: The Summer issue of G&G is bursting with new content! Three feature articles characterize gemstones—diamonds, amber, and nephrite, respectively—from known sources and offer the means to distinguish their geographic origin. Two additional full-length articles analyze gems from the coronation crown of Napoleon III and the unusual surface features of ekanite from Sri Lanka. Meanwhile, the journal’s regular sections continue to delight with interesting finds from around the world.
A LOOK AT DIAMONDS AND DIAMOND MINING IN GUYANA
The lead article by Roy Bassoo and Kenneth Befus combines direct observations, government reports, and historical accounts to provide a detailed gemological description of diamonds from Guyana. Their overview of diamond production describes the morphology, chemical content, and luminescence features of these alluvial diamonds prized for their clarity and color.
THE SHAPE OF EKANITE
Lutz Nasdala and coauthors characterize the physical properties, chemical composition, and general appearance of ekanite found in Ampegama, Sri Lanka, comparing them against samples from other deposits in the country. The remarkably uneven shapes and bumpy surface features of these ekanite fragments lead them to identify the processes responsible for the distinctive appearance.
A GEMOLOGICAL AND SPECTROSCOPIC STUDY WITH MOBILE INSTRUMENTS OF “EMERALDS” FROM THE CORONATION CROWN OF NAPOLEON III
In an effort to examine gemstones of historical significance, Stefanos Karampelas and fellow researchers use nondestructive mobile gemological and spectroscopic instruments to analyze 45 “emeralds” formerly set in the coronation crown of Napoleon III. Their efforts uncover the true identity of these gems, verifying that 41 are indeed natural emerald, probably of Colombian origin, while the remaining four are artificial glass.
CHARACTERISTICS OF NEWLY DISCOVERED AMBER FROM PHU QUOC, VIETNAM
A team led by Le Ngoc Nang discovers an amber deposit amid sandstone boulders on the island of Phu Quoc, Vietnam’s only known amber locality to date. Their article presents the gemological properties of this newly sourced amber and shows that FTIR spectroscopy can differentiate Phu Quoc from other global sources.
NATURAL RADIOACTIVITY IN SELECT SERPENTINITE-RELATED NEPHRITE SAMPLES: A COMPARISON WITH DOLOMITE-RELATED NEPHRITE
Dariusz Malzcewski and coauthors use low-background gamma-ray spectrometry to measure potassium, thorium, and uranium activity concentrations in nephrite from Poland, Russia, Canada, and New Zealand. Their studies prove that Th/U ratios appear unique according to geographic region. In addition, they conclude that nephrite does not pose a radiological risk to artisans or collectors who handle this ornamental material.
LAB NOTES
GIA’s global laboratory staff present their latest findings in the Lab Notes section, including an exceptionally rare 2.29 ct bright orange benitoite, the internally flawless 15.10 ct De Beers Cullinan Blue diamond, and a color-change sapphire exhibiting both asterism and chatoyancy.
MICRO-WORLD
The Micro-World section, dedicated to the inner world of gemstones, features a blue apatite crystal beautifully framed by rutile needles in garnet, an extensive network of eye-visible etch channels in diamond, and a labyrinth pattern in the fracture filling of an emerald.
COLORED STONES UNEARTHED
Colored Stones Unearthed returns to explore the fascinating realm of inclusions in gemstones. The microscopic inclusions within a gemstone can reveal a great deal about the host material. In this installment, learn how inclusions form, how they are studied, and what information gemologists and geoscientists can uncover.
GEM NEWS INTERNATIONAL
Finally, GNI contributors report on various topics ranging from gem identification to responsible practices to auction and museum highlights. Two entries feature gems that can change color—a photochromic zircon that reacted after exposure to long-wave UV and two sapphires that shifted between orange and yellow hues, providing an interesting case study on color stability. Gain insight on creating a sustainable and responsible emerald industry with Myne London, an ethical emerald supplier with a goal of supporting women’s economic empowerment in the gem trade. Finally, the spring 2022 auction season was buzzing with plenty of top-notch gems on the block, including two diamonds weighing more than 200 ct each and several gems fetching record prices. @chapter:7


Publication Year: 2018 Title: Diamond Identification Abstract: Figure 1. The canary yellow diamonds from this study showed much lower concentrations of isolated nitrogen than regular type Ib yellow diamonds, which usually show brownish and greenish hues linked to plastic deformation. Photo by Sood Oil (Judy) Chia.

Canary Yellow Diamonds
Wuyi Wang1 and Terry Poon2
1GIA, New York
2GIA, Hong Kong
Isolated nitrogen is one of the major defects in producing yellow color in natural diamonds. In regular type Ib yellow diamonds, isolated nitrogen is normally the dominant form, with limited aggregations in A centers (nitrogen pairs). Type Ib diamonds normally experienced strong plastic deformations. In addition to vacancy clusters, many other optic centers were introduced during annealing over their long geological history, such as GR1, NV, and H3 centers. Diamonds from the Zimmi area of West Africa are a typical example (Smit et al., 2016). As a result, clear brownish and greenish hues are common among these diamonds, so most do not possess true “canary” yellow color. Here we studied more than 2,000 diamonds with real canary yellow color. Their color origin and relationship with type Ib diamonds were explored.
Sizes of the studied diamonds ranged from 0.01 to about 1.0 ct. They showed pure yellow color, with grades of Fancy Intense or Fancy Vivid yellow. Infrared absorption analysis showed that they were all type IaA with very high nitrogen concentrations, but a very weak absorption from isolated nitrogen at 1344 cm–1 was detected in all samples. Concentration of isolated nitrogen was estimated at ~2–3 ppm. This isolated nitrogen created smooth absorption in the ultraviolet-visible (UV-Vis) region, increasing gradually to the high-energy side. No other defects were detected using UV-Vis absorption spectroscopy, which explained the pure yellow color we observed. Fluorescence imaging revealed multiple nucleation centers with dominant green color, which was attributed to the S3 defects confirmed through photoluminescence analysis. Compared with natural type Ib diamonds, an outstanding feature of the studied samples is the absence of plastic deformation. For this reason, other vacancy-related defects were not introduced to these diamond lattices over the geological period after their formation.
Sulfide inclusions are common in type Ib diamonds, but they were not observed in these canary stones. Instead, some calcite inclusions were observed. All the observations from this study indicated that the canary diamond samples were formed in a different geological environment than type Ib diamonds.
REFERENCE
Smit K.V., Shirey S.B., Wang W. (2016) Type Ib diamond formation and preservation in the West African lithospheric mantle: Re-Os age constraints from sulphide inclusions in Zimmi diamonds. Precambrian Research, Vol. 286, pp. 152–166, http://dx.doi.org/10.1016/j.precamres.2016.09.022
Addressing the Challenges of Detecting Synthetic Diamonds
David Fisher
De Beers Technologies, Maidenhead, United Kingdom
The dream of growing synthetic diamonds existed for many centuries before it was achieved in the 1950s. The development of techniques to identify synthetic diamonds and enable their reliable separation from natural diamonds has not had the luxury of centuries to work with. Since the early reports on the characteristics of laboratory-grown stones, scientists have been working steadily to establish and improve the means of detection. For many years the De Beers Group has been developing equipment for rapidly screening and testing for potential synthetic and treated diamonds as part of a strategy aimed at maintaining consumer confidence in natural untreated diamonds. This work has been underpinned by extensive research into defects in natural and synthetic diamond, either conducted within De Beers’ own facilities or through financial and practical support of research in external institutions.
Key to any detection technique for synthetic diamonds is a fundamental understanding of the differences between them and natural diamonds. This could take the form of differences in the atomic impurity centers or differences in the spatial distributions of these centers brought about by very significant distinctions in the growth environments. The former was used in the development of the DiamondSure instrument that, among other things, detects variance differences in the absorption spectra due to the presence or absence of the N3 feature. This absorption is from a nitrogen-related defect that is usually only produced in nitrogen-containing diamonds by extended periods at relatively high temperatures—that is, conditions generally experienced by natural diamonds. Growth-related differences in impurity distributions can be very accurately imaged using the DiamondView instrument. Short-wave ultraviolet (UV) light is used to excite luminescence from a very thin layer of diamond near the surface to give images free from the blurring encountered with more common longer-wavelength excitation sources. DiamondView has, since its launch, provided the benchmark for the detection of synthetic diamonds.
A number of approaches involving absorption features have been developed, including the use of almost complete absorption in the ultraviolet region of the spectrum to indicate that a diamond is not synthetic. The UV absorption is produced by the A center (two adjacent nitrogen atoms) and is rarely encountered in as-grown synthetic diamonds. The main form of nitrogen in synthetic diamonds is a single substitutional nitrogen atom that absorbs in both the ultraviolet and visible regions to produce yellow color. The combination of UV absorption and no strong yellow color is therefore restricted to natural diamond. However, treatment of nitrogen-containing synthetic diamonds is capable of generating A centers, but generally does not produce a colorless stone. This effect accounts for the careful color ranges often applied to instruments relying on UV absorption for screening. This also highlights one of the limitations of absorption spectroscopy: When smaller stones are tested, the amount of absorption decreases and the technique becomes less reliable. In recent years we have seen a shift to smaller sizes (below 0.01 ct) in the synthetic diamonds being offered for sale to the jewelry market, and screening techniques have had to evolve to address this situation and the limitations of absorption-based approaches.
Testing melee-sized diamonds, as well as introducing technical challenges around the measurement technique, has also led to the introduction of greater automation. In 2014 the De Beers Group introduced the first automated melee screening instrument (AMS1), which combined the measurement technique from DiamondSure with automated feeding and dispensing of stones in the range of 0.20 to 0.01 ct. While this instrument was well received and effectively addressed concerns around synthetic melee-sized stones in the trade at the time, there soon came calls for improvements—a faster instrument capable of measuring smaller stones, no restrictions on cut, and a lower referral rate for natural diamonds. These requirements proved impossible to meet with the limitations imposed by absorption measurements, and a new technique based on time-resolved spectroscopy was developed. This resulted in the AMS2 instrument, launched in March 2017. The AMS2 processes stones at a speed of one stone per second, 10 times faster than the AMS1. It measures round brilliants down to 0.003 ct (0.9 mm diameter) and can be used on other cuts for stones of 0.01 ct and above. The measurement technique itself has been incorporated into the SYNTHdetect (figure 1, left), an instrument launched in September 2017 that allows manual observation of the time-resolved emission. Besides providing the same testing capability as AMS2 (figure 1, right) for loose stones, various holders allow testing of mounted stones in a wide range of configurations. The benefit of this approach is that stones tested loose using AMS2 will generate a broadly consistent result when mounted on SYNTHdetect.

Figure 1. The De Beers Group instruments SYNTHdetect (left) and AMS2 (right) provide screening capability for melee-size diamonds as small as 0.3 points. Photo courtesy of Danny Bowler © De Beers Group.
Changes in growth processes for synthetic diamonds have also led to the gradual introduction of new characteristics. High-pressure, high-temperature (HPHT) synthetics have tended to be fairly consistent in their growth-related luminescence patterns, while significant variations in the features associated with chemical vapor deposition (CVD) synthetics have been observed. These continue to be well documented and have led to the gradual evolution of the DiamondView instrument and the way in which it is used.
Post-growth treatment of synthetic diamonds can be applied for a number of reasons: improvement in the color, modification of the atomic defects to make the stones look more like a natural diamond, and removal of a characteristic that could be used to identify a synthetic diamond. The motivation for the latter two treatments can only be described as fraudulent. The challenge in developing detection instruments and techniques is to ensure that they are as robust as possible in the face of such challenges. Treatment techniques will rarely have any effect on the growth patterns associated with synthetic diamonds, and it is therefore very difficult to treat synthetics in a way that would make them undetectable using the DiamondView. Screening instruments tend to be based on a single technique, and it is important that the approach adopted not be vulnerable to simpler forms of treatment. This has been of primary concern to the De Beers Group in the development of our own screening instruments. It has also been necessary in certain cases to withhold detailed information about detection techniques where disclosure of this would lead to undermining of the detection technique itself.
The De Beers Group continues to invest heavily in growth and treatment research in order to develop the next generation of instruments and techniques that will assist the trade in maintaining detection capability to support consumer confidence. The Group is uniquely placed in the industry to address these challenges due to its collaboration with Element Six (world leaders in synthesis of diamond for industrial and technical applications) and its in-depth knowledge of the properties of natural diamonds with known provenance from its own mines.
Diamond at the Diffraction Limit: Optical Characterization of Synthetic Diamond
Phil L. Diggle1,2, Ulrika F.S. D’Haenens-Johansson3, Wuyi Wang3, and Mark E. Newton1,2
1Department of Physics, University of Warwick, Coventry, United Kingdom
2EPSRC Centre for Doctoral Training in Diamond Science and Technology, Warwick, United Kingdom
3GIA, New York
Diamond, known for its splendor in exquisite jewelry, has been synthesized since the 1950s. In the last six decades, the perfection of laboratory-grown single-crystal diamond has vastly improved through the research and development of two main synthesis techniques. One replicates Earth’s natural process, where the diamond is grown in the laboratory under conditions of diamond stability at high temperature and high pressure (HPHT). The other technique relies on the dissociation of methane (or other carbon-containing source gas) and hydrogen and the subsequent deposition of diamond at low pressures from the gaseous phase in a process known as chemical vapor deposition (CVD). In the latter case, diamond is not the stable form of carbon, but the kinetics in the CVD process are such that diamond wins out. Large gem-quality synthetic diamonds are now possible, and a 6 ct CVD (2018) and a 15.32 ct HPHT (2018) have been reported.
It is of course possible to differentiate laboratory-grown from natural diamond based on how extended and point defects are incorporated into the crystal. Furthermore, treated diamond can be identified utilizing knowledge of how defects are produced and how they migrate and aggregate in both natural and synthetic diamond samples. Room-temperature confocal photoluminescence microscopy can be used to image the emission of light from defects in diamond with a spatial resolution limited only by the diffraction limit; a lateral spatial resolution approaching 300 nm is routinely achieved (figure 1). It is possible with this tool to identify point defects with concentrations less than 1 part per trillion (1011 cm–3).

Figure 1. Left: DiamondView fluorescence imaging shows dislocation networks in a natural type IIa diamond. Right: A room-temperature confocal photoluminescence image taken with 488 nm excitation shows H3 defects following a dislocation network pattern within the diamond. Some of the fluorescent spots are single H3 centers.
This talk will outline the experimental setup, how this tool has been used to identify the decoration of dislocations with point defects in CVD lab-grown diamond, and how different mechanisms for defect incorporation operate at growth sector boundaries in HPHT synthetic diamond.
Fluorescence in Diamond: New Insights
Ans Anthonis, John Chapman, Stefan Smans, Marleen Bouman, and Katrien De Corte
HRD Antwerp, Belgium
The effect of fluorescence on the appearance of diamonds has been a subject of debate for many years (Moses et al., 1997). In the trade, fluorescence is generally perceived as an undesirable characteristic. Nearly 80% of diamonds graded at HRD Antwerp receive a “nil” fluorescence grade, while the remainder are graded as “slight,” “medium,” and “strong,” their value decreasing with level of fluorescence.
To understand how fluorescence might change diamond appearance, a selection of 160 round brilliant-cut diamonds were investigated in detail. This study focused on the effect of fluorescence on diamond color. The aim was to determine under what lighting conditions the color of a diamond could change and the magnitude of that effect. We also investigated a smaller selection of diamonds with multiple spectroscopic absorption techniques to study the origin of their fluorescence.
The lighting arrangement we used combined the UV from light-emitting diode (LED) lamps with the light from a daylight-equivalent (grading) fluorescent lamp that had its UV component filtered out. With controlled UV output and after calibrations, it was possible to simulate different illuminations, including outdoors, indoors near a window, office lighting, and grading environments. The grading environment provided the reference color. Diamonds were presented in both table-down and table-up orientations, with the degree of effect determined by visual comparison with nonfluorescent master stones. For each color, both experienced diamond graders and nonprofessionals examined the possible effect of fluorescence on color appearance.
It was found that the UV level in office lighting was insignificant and did not produce any observable effect even with “very strong” fluorescence. However, with daylight from either outdoors or indoors, near a window, the relative strength of UV was significant, sufficient to create a positive color change. For samples with a “very strong” fluorescence, the results are shown in figure 1. For each color, ranging from D to J, the color shift caused by exposure to different UV levels—represented by the different lighting conditions—is illustrated.

Figure 1. For samples with “very strong” fluorescence, the observed color in different lighting conditions (outdoor, indoor, and office) is shown. These samples were graded through the pavilion (table-down). Note that in an outdoor environment, J colors can appear as D colors.
REFERENCE
Moses T.M., Reinitz I.M., Johnson M.L., King J.M., Shigley J.E. (1997) A contribution to understanding the effect of blue fluorescence on the appearance of diamonds. G&G, Vol. 33, No. 4, pp. 244–259, http://dx.doi.org/10.5741/GEMS.33.4.244
Fluorescence, Phosphorescence, Thermoluminescence, and Charge Transfer in Synthetic Diamond
Jiahui (Gloria) Zhao1,2, B.G. Breeze1,3, B.L. Green1, Phil L. Diggle1,2, and Mark E. Newton1,2
1Department of Physics, University of Warwick, Coventry, United Kingdom
2EPSRC Centre for Doctoral Training in Diamond Science and Technology, Warwick, United Kingdom
3Spectroscopy Research Technology Platform, University of Warwick, Coventry, United Kingdom
Photoluminescence (PL) and phosphorescence underpin many of the discrimination techniques used to separate natural from synthetic diamond. PL is at the heart of many new quantum technologies based on color centers in lab-grown diamonds. In HPHT synthetic diamond, the phosphorescence observed is explained in terms of donor-acceptor pair recombination. The thermal activation of electrons to neutral boron acceptors shows that boron plays a key role in the phosphorescence process. However, there are a number of things we struggle to explain. For example, the phosphorescence peak positions are not fully explained, and there is no conclusive link between the emission and charge transfer involving the substitutional nitrogen donor.
Secondly, the origin of the phosphorescence observed in some synthetic diamond samples grown by the CVD process is unclear. Although we now have evidence for unintentional boron impurity incorporation at stop-start growth boundaries in some CVD synthetic samples, it is possible that some of the observed phosphorescence does not involve boron impurities.
In this paper we report on the results of combined fluorescence, phosphorescence, thermoluminescence, and quantitative charge transfer investigations undertaken on both HPHT and CVD synthetic diamond, with the objective of identifying which defects are involved in the fluorescence and phosphorescence processes.
LPHT-Treated Pink CVD Synthetic Diamond
Hiroshi Kitawaki, Kentaro Emori, Mio Hisanaga, Masahiro Yamamoto, and Makoto Okano
Central Gem Laboratory, Tokyo
Pink diamond is extremely popular among fancy-color diamonds, which has prompted numerous attempts to produce pink diamond artificially. Pink CVD synthetic diamonds appeared on the gem market around 2010. Their color was produced by a multistep process combining post-growth HPHT treatment to remove the brown hue and subsequent electron irradiation, followed by low-temperature annealing. Pink CVD synthetic diamonds treated only with low pressure and high temperature (LPHT), without additional post-growth irradiation, have also been reported but are rarely seen on the market.
Recently, a loose pink stone (figure 1) was submitted to the Central Gem Laboratory in Tokyo for grading purposes. Our examination revealed that this 0.192 ct brilliant-cut marquise was a CVD synthetic diamond that had been LPHT treated.

Figure 1. LPHT-treated brownish pink CVD synthetic diamond weighing 0.192 ct. Photo by Hiroshi Kitawaki.
Visually, this diamond could not be distinguished from natural diamonds with similar color. However, three characteristics of CVD origin were detected:

C-H related absorption peaks between 3200 and 2800 cm–1, located with infrared spectroscopy
A luminescence peak at 737 nm, detected with photoluminescence (PL) spectroscopy
A trace of lamellar pattern seen in the DiamondView

However, irradiation-related peaks such as at 1450 cm–1 (H1a), 741.1 nm (GR1), 594.3 nm, or 393.5 nm (ND1) that are seen in the pink CVD diamonds treated with common multi-step processes were not detected.
The presence of four peaks at 3123, 2901, 2870, and 2812 cm–1 between 3200 and 2800 cm–1 suggests this stone was LPHT treated; the following observations indicate that it was not HPHT treated:

The 3123 cm–1 peak presumably derived from NVH0 disappears after a normal HPHT treatment.
The 2901, 2870, and 2812 cm–1 peaks are known to shift toward higher wavenumbers as the annealing temperature rises. Our own HPHT treatment experiments on CVD-grown diamonds proved that the 2902 and 2871 cm–1 peaks detected after 1600°C annealing shifted to 2907 and 2873 cm–1 after 2300°C annealing. The peak shift of 2901, 2870, and 2812 cm–1 is also related to the pressure during the annealing, as these peaks shifted to 2902, 2871, and 2819 cm–1 at the higher pressure of 7 GPa compared to 2900, 2868, and 2813 cm–1 at the ambient pressure under the same annealing temperature of 1600°C.
Absorption peaks at 7917 and 7804 cm–1 in the infrared region and at 667 and 684 nm in the visible range were also detected, which coincide with the features seen in LPHT-treated stones. From the combination of the intensity ratios of optical centers such as H3 and NV centers that were detected with PL measurement, this sample is presumed to have been treated with LPHT annealing at about 1500–1700°C as a post-growth process.

In recent years, CVD synthetic diamonds have been produced in a wider range of colors due to progress in the crystal growth techniques and post-growth treatments. Although HPHT treatment has been employed mainly to improve the color in a diamond, LPHT annealing may become widespread as the technique is further developed. Gemologists need to have deep knowledge about the optical defects in such LPHT-treated specimens.
Recent Developments in Detection and Gemology in China, Particularly for Chinese Synthetic Diamonds
Jie Ke, Taijin Lu (presenter), Yan Lan, Zhonghua Song, Shi Tang, Jian Zhang, and Hua Chen
National Gemstone Testing Center (NGTC), Beijing
China is the world’s largest producer of HPHT-grown industrial diamonds. Its 2016 production of about 20 billion carats accounted for 98% of the global supply. Since the beginning of 2015, melee-sized colorless HPHT synthetic diamonds have been tested at the National Gemstone Testing Center’s (NGTC) Shenzhen and Beijing laboratories in parcels submitted by different clients, which means that colorless HPHT synthetic diamonds have entered the Chinese jewelry market and may be mistaken for natural diamonds.
CVD synthesis technology has grown rapidly in recent years. Large colorless and colored (blue, pink) CVD-grown diamonds have been entering the market, and a few have been fraudulently sold as natural diamonds.
China has independently developed gem-grade HPHT synthetic diamond production technology since 2002, and can grow gem-grade type Ib, IIa, and IIb and high-nitrogen-content synthetic diamonds in volume, depending on market needs. Gem-grade type Ib, IIa, and IIb HPHT synthetic diamonds have been grown using the temperature gradient method, under a cubic press at high pressure (e.g., 5.4 GPa) and high temperature (1300–1600°C). Driven by a specific temperature gradient, the carbon source from high-purity graphite (>99.9%) located at the high-temperature zone can diffuse into the seed crystals in the cubic press, resulting in the crystallization of synthetic diamonds. Chinese production of melee-sized colorless to near-colorless HPHT synthetic diamonds accounts for about 90% of the global output.
Gem-grade type IIa and IIb CVD synthetic diamonds are grown using the microwave plasma chemical vapor deposition (MPCVD) and direct current (DC) arc plasma methods. Faceted colorless CVD diamonds can be grown in sizes up to 6 ct by at least two Chinese companies (table 1).

After testing and analyzing thousands of natural and synthetic diamonds collected directly from the Chinese companies, NGTC independently developed the GV5000, PL5000, DS5000, and ADD6000 instruments for rapidly screening and identifying the diamonds based on the gemological characteristics obtained.
Besides HPHT and CVD synthetic diamonds, a thickly layered hybrid diamond consisting of both natural and CVD material was identified at the NGTC Beijing laboratory (figure 1). The identification features and properties of regrown CVD synthetic diamonds using natural type Ia diamond crystals as seeds will be reported.

Figure 1. DiamondView fluorescence image of the hybrid natural and CVD-grown diamond. Photo by Shi Tang.
The current status and features of colored stones examined at NGTC laboratories, including several cases studies, will be discussed.
Summary of CVD Lab-Grown Diamonds Seen at the GIA Laboratory
Sally Eaton-Magaña
GIA, Carlsbad, California
While chemical vapor deposition (CVD) diamond growth technology has progressed significantly in recent years, with improvements in crystal size and quality, the use of these goods in the jewelry trade is still limited. Not all CVD-grown gem diamonds are submitted to GIA for grading reports, and they only account for about 0.01% of GIA’s annual diamond intake (both D–Z equivalents and fancy color; Eaton-Magaña and Shigley, 2016). The CVD process involves diamond growth at moderate temperatures (700–1300°C) but very low pressures of less than 1 atmosphere in a vacuum chamber (e.g., Angus and Hayman, 1988; Nad et al., 2015). This presentation summarizes the quality factors and other characteristics of the CVD-grown material submitted to GIA (e.g., figure 1) and discusses new research and products.

Figure 1. Spectra and fluorescence images of all D–N equivalent CVD-grown diamonds seen at GIA from 2007 to 2018 were analyzed. The vast majority (74%) show features consistent with post-growth HPHT treatment. The percentage of as-grown CVD products increases as the equivalent color progresses from the colorless range (D–F) to near-colorless (G–J) to faint brown (K–N).
Today the CVD process is used to produce high-color (as well as fancy-color) and high-clarity type II diamonds up to several carats in size. The majority of the CVD material seen at GIA consists of near-colorless (G–N equivalent) with colorless (D–F equivalent) and various “pink” hues. Additionally, CVD material is constantly setting new size milestones, with the announcement of an approximately 6 ct round brilliant earlier this year (Davis, 2018). However, the attainable sizes among CVD products are dwarfed by those from the HPHT process, with 15.32 ct as the current record for a faceted gem (Ardon and Eaton-Magaña, 2018).
One particular challenge for gemologists (albeit very rarely encountered) comes from the lab-grown/natural hybrids (figure 2) that have been submitted to and documented by gemological laboratories (e.g., Moe et al., 2017; Tang et al., 2018). In these specimens, the grower places a natural diamond into the CVD reactor as the seed plate, with both components retained in the faceted gem. If the manufacturer is using a colorless natural type Ia diamond as a seed plate for near-colorless CVD growth, the hybrid cannot undergo any post-growth HPHT treatment, as this would radically alter the natural seed by turning the natural diamond yellow. If the manufacturer is creating a CVD overgrowth layer on a faceted natural diamond, the intent is to either add weight to a diamond that may be near a weight boundary or to achieve a color change, typically to blue. These hybrid products also make it more difficult to infer a diamond’s history based solely on its diamond type.

Figure 2. This 0.33 ct CVD-grown/natural diamond composite with a color equivalent to Fancy blue was previously described (Moe et al., 2017). DiamondView illumination clearly shows the interface between the lab-grown and natural components.
The CVD process has also created some unique gems that have not been duplicated among natural, treated, or HPHT-grown diamonds. These include CVD-grown diamonds with a high concentration of silicon impurities, which create a pink to blue color shift. In those samples, a temporary effect was activated by UV exposure, which precipitated a charge transfer between negative and neutral silicon-vacancy centers (D’Haenens-Johansson et al., 2015).
Also recently seen are type IIb CVD goods. Some that were submitted by clients had a low boron concentration (3 ppb, with G-equivalent color and 1.05 carat weight). Meanwhile, some research samples produced by a manufacturer in China and fashioned as flat plates had dark bluish coloration and very high boron concentration (2500 ppb and higher). Also among that suite of flat-plate CVD samples was one with a black color caused by extremely high amounts of nitrogen-vacancy centers.
Although new CVD products are continually being manufactured and introduced to the trade, the laboratory-grown diamonds examined to date by GIA can be readily identified.
REFERENCES
Angus J.C., Hayman C.C. (1988) Low-pressure, metastable growth of diamond and diamondlike phases. Science, Vol. 241, No. 4868, pp. 913–921.
Ardon T., Eaton-Magaña S.C. (2018) Lab Notes: 15 carat HPHT synthetic diamond. G&G, Vol. 54, No. 2, pp. 217–218.
Davis A. (2018) Washington, D.C., company grows 6-carat diamond. National Jeweler, Jan. 31, https://www.nationaljeweler.com/diamonds-gems/supply/6267-washington-d-c-company-grows-6-carat-diamond
D’Haenens-Johansson U.F.S., Ardon T., Wang W. (2015) CVD synthetic gem diamonds with high silicon-vacancy concentrations. Conference on New Diamond and Nano Carbons, May 2015, Shizuoka, Japan.
Eaton-Magaña S.C., Shigley J.E. (2016) Observations on CVD-grown synthetic diamonds: A review. G&G, Vol. 52, No. 3, pp. 222–245, http://dx.doi.org/10.5741/GEMS.52.3.222
Moe K.S., Johnson P., D’Haenens-Johansson U.F.S., Wang W. (2017) Lab Notes: A CVD synthetic diamond overgrowth on a natural diamond. G&G, Vol. 53, No. 2, pp. 237–239.
Nad S., Gu Y., Asmussen J. (2015) Growth strategies for large and high quality single crystal diamond substrates. Diamond and Related Materials, Vol. 60, pp. 26–34, http://dx.doi.org/10.1016/j.diamond.2015.09.018
Tang S., Su J., Lu T., Ma Y., Ke J., Song Z., Zhang J., Liu H. (2018) A thick overgrowth of CVD synthetic diamond on a natural diamond. Journal of Gemmology, Vol. 36, No. 2. pp. 237–239. @chapter:11


Publication Year: 2023 Title: The India International Jewellery Show has boosted jewelry sales to unprecedented levels. Abstract: The Gem & Jewellery Export Promotion Council (GJEPC) under the Ministry of Commerce of India announced that the 39th edition of the India International Jewellery Show (IIJS) Premiere 2023, held from August 3-7 last year, generated approximately 300 billion Baht in revenue. The event saw participation from 1,850 exhibitors worldwide and attracted over 50,000 visitors, including 2,100 international attendees from 65 countries. The exhibition took place simultaneously at two venues in Mumbai: the Jio World Convention Centre and the Bombay Exhibition Centre.
Market trends in the Indian jewellery sector indicate sustained demand for traditional natural diamonds, with an increasing preference for lab-grown diamonds (LGD) as components in jewellery, alongside pearls and colored gemstones. This trend aims to cater to both the domestic Indian market, especially appealing to environmentally conscious younger generations, and export markets like Europe and the United States, which have shown increased imports from India.
Additional insights and comments:
Thailand's competitive potential in the Indian market, particularly in sustainable silver jewellery, has been solidified by rising consumer expenditure, notably during the peak wedding season at the beginning of each year. Thailand holds a consistent 70% market share in India, competing with countries like the United States, China, Italy, Hong Kong, UAE, and Turkey. Noteworthy competitors include Singapore, Hong Kong, UAE, and Australia, which have increased their imports into India following the signing of the FTA with India in 2021.
Thai exporters may leverage strengths in using natural pearls, synthetic diamonds (Lab-grown Diamonds), and silver jewellery, meeting the preferences of young working professionals and higher-income individuals. Additionally, they could allocate funds to produce other fashion items such as brooches, buckles (accessories), scarves, and handbags. India, unlike Thailand, lacks expertise in integrating silver threads into textiles (woven silver textile). Cities more open to silver jewellery than others include Kolkata, Chennai, and Hyderabad in eastern and southern India. @chapter:30


Publication Year: 2018 Title: Quarterly Crystal: Wurtzite Phantom in Quartz Abstract: Figure 1. Measuring 86.38 mm and weighing 1,140 ct, this quartz crystal from British Columbia contains a three-sided phantom composed of an abundance of opaque black wurtzite inclusions. Photo by Robison McMurtry.
Transparent colorless rock crystal quartz is a strong, durable mineral that makes a favorable host for a wide variety of inclusions (see the three-volume Photoatlas of Inclusions in Gemstones for examples). The geographic source of the crystal pictured in figure 1 is British Columbia, Canada. At 1,140 ct and 86.38 mm in length, this large example of rock crystal plays host to several near-surface opaque black hexagonal to trigonal crystals as large as 5.0 mm.
As shown in figure 2, the micromorphology of the numerous inclusions, forming a three-sided phantom, suggests that they might be the zinc iron sulfide wurtzite. Laser Raman microspectrometry confirmed the identification of the inclusions as wurtzite. The euhedral inclusions were situated in the quartz crystal in the form of directional phantoms that developed through the directional deposition of the wurtzite on three consecutive surfaces of the quartz, which then continued to grow, enveloping the wurtzite as inclusion planes tracing the form of the original quartz host. From what we can determine, this is the first time that wurtzite has been found as an inclusion in any gem material. Because of wurtzite’s relationship to sphalerite, some inclusions previously identified as sphalerite may actually be wurtzite.

Figure 2. The crystals in this phantom plane in quartz were identified by Raman analysis as wurtzite. Photomicrograph by Nathan Renfro; field of view 19.2 mm. @chapter:13


Publication Year: - Title: Postdoctoral Program Gives Scientists Access to Rare Research Opportunities Abstract: Evan Smith, whose expertise is in diamond geology, is systematically characterizing the inclusions he sees in rare types of diamonds to fill in some of the missing pieces in our understanding of how diamonds form and what they mean for the evolution of the planet. Photo by Siu Bo Wong Huang /GIA

Evan M.Smith was “blown away” by the first big diamonds he was able to work with at GIA.

“I was used to working with much smaller, lower-quality diamonds,” says Smith, who began working in the research department in New York in 2015. “I was very excited to be able to peek behind the curtain to see the variety of diamonds − and the very expensive ones − that are impossible to access for research anywhere else.”

Smith, whose expertise is in diamond geology, is working at GIA as part of the Richard T. Liddicoat Postdoctoral Research Fellowship program, which was created in 2014 in honor of GIA’s former president, who was widely considered the “Father of Modern Gemology.” It gives researchers who study mineralogy, geology, physics, materials science and other fields related to gemology access to GIA’s gemological data, equipment and the rare, unusual and large gems that come into the laboratories. Each position is tailored to focus on the research fellow’s expertise and interest with the opportunity to examine fundamental issues related to diamonds, colored stones, pearls and instrument development.

“We have had the opportunity to bring in some exceptional and highly motivated academic researchers through this program,” says Dr. Wuyi Wang, GIA’s director of research and development. The postdoctoral researchers work side-by-side with the Institute’s experienced researchers and gemologists, and together, they explore and learn from the gems that come into GIA’s lab.

The Liddicoat Postdoctoral Research Fellowship program is part of GIA’s extensive and ongoing research into the characteristics of diamonds and other gems. To that end, Liddicoat Postdoctoral Research Fellows are expected to conduct creative, independent, publishable research and are strongly encouraged to collaborate with GIA scientists as well as outside research institutions and universities.

Smith says the opportunities he has had to see some very rare diamonds and to learn from “the wealth of experience of people who have spent years inspecting and observing diamonds” will hopefully help him “shed some light on some aspects of diamond geology that perhaps have gone unnoticed by the geological community.”
Evan Smith: Diamond Inclusions and the Clues to the Earth’s Formation
Evan M. Smith, originally from Canada, near Toronto, specializes in diamond geology, which he says covers everything from the processes that make diamonds deep in the earth, to the ones that bring them to surface. As a geologist, he uses diamonds to help him understand how the Earth formed.

“Diamonds are a physical sample of carbon from the deep earth, and carbon is intimately involved in the evolution of the earth as we know it, from 4.6 billion years ago to today,” he says. “This means that diamonds give us a record of a broad range of processes, such as the formation of continents and the beginnings of plate tectonics.”

He worked in the mineral exploration industry looking for deposits of gold, or copper or other commodities after college and then at the Ekati diamond mine in northern Canada characterizing the various details of the rocks that contain diamonds. He became interested in the postdoctoral research program at GIA because of the potential to study diamonds that would otherwise be difficult – or impossible – for him to access.

“Diamonds are one of the most scientifically valuable minerals on the planet, but getting access to them for research purposes is often challenging because of their great value as gemstones,” he says. “The large numbers of diamonds that come through GIA for grading means that rare and unusual diamonds are almost a routine occurrence here.”

Smith is focused on inclusions in diamonds, materials the diamond has brought to the surface.

“When diamonds grow, sometimes they trap pieces of the surrounding minerals or fluid deep in the earth. When I say deep, I mean about 100 miles into the earth, and in some cases perhaps even all the way down to the core-mantle boundary at about 1,798 miles,” he says. “When diamonds are carried to the surface in a volcanic eruption, the diamond acts to protect and shield any inclusions trapped inside. No other mineral can provide such pristine samples of the deep earth.”

Smith is systematically characterizing the inclusions he sees in rare types of diamonds to fill in some of the missing pieces in our understanding of how diamonds form and what they mean for the evolution of the planet. He says that before he came to GIA, he was limited to working on smaller, less valuable diamonds, which is a problem because some particularly large, high quality diamonds might form in a different and unique way. Being able to access a wide variety of diamonds at GIA gives him the opportunity to see diamonds that have formed in a broader range of geological settings.

Smith is also searching for fluid in diamonds, such as nitrogen, water, carbon dioxide and methane, which also provide clues as to what happens deep in the Earth.

“A few years ago, I identified very small inclusions of liquid nitrogen trapped in diamonds from at least three different continents. The nitrogen is held under tremendous pressure, which allows it to be in liquid form at room temperature,” he says. “These fluids give clues about how different kinds of diamonds form and even how the atmosphere formed and changed over time.”

Smith says the diamond research he does – and the clues to the Earth’s formation he is seeking – would not be possible if people didn’t want diamonds for their jewelry.

“The desirability of diamond as a gemstone is the very reason it is mined. Otherwise, diamonds would remain buried in rocks and hidden in river gravels,” he says. “Nobody would ever get to study them or discover their fascinating secrets about the Earth.”
Elena Sorokina: The Genesis and Evolution of Corundum
Elena Sorokina, from Russia, graduated from the Russian State Geological prospecting University (MGRI - RSGPU) in Moscow in 2007 and started her Ph.D. program in gemology. She continued her Ph.D. education when she transferred to the Fedorovsky All-Russian Research Institute of Mineral Resources (FGUP VIMS) in 2009 as a junior researcher. In FGUP VIMS, she worked as a classical mineralogist conducting research on ore deposits from the geological prospecting stage to studying ore processing products.

Sorokina joined the Fersman Mineralogical Museum of the Russian Academy of Sciences in Moscow as a research fellow in 2012. After a scholarship award by the German Academic Exchange Service (DAAD), she became a visiting researcher (2013-2014) at the Center of Gem-Materials Research in Johannes Gutenberg University Mainz in Germany, which is an active part of Institute of Gemstone Research Idar-Oberstein. In University Mainz, her research experience extended to non- and micro-destructive technique, such as a laser ablation-inductively coupled plasma-mass spectrometry and different spectroscopic equipment.

Sorokina became a postdoctoral research fellow at GIA in Carlsbad in September 2015 and is focusing on the theories and ideas about the genesis and evolution of gem corundum, as well as mineral development within crystalline materials in natural environments. She is studying the questions related to the mineral crystallization and/or recrystallization, growth and purification during geological events.

“GIA provides excellent opportunities for young scientists at their early-career stage, allowing them to demonstrate the level of independence required to develop competitive and innovation research,” she says. “All the facilities and equipment are available from the GIA laboratories in New York and Carlsbad, including non- and micro-destructive techniques, which are a great advantage in studying gemstones.”

The major focus of Sorokina’s research lies across different science disciplines – gemology, mineralogy, geology, materials science and engineering.

“GIA provides the perfect environment for inter-disciplinary collaborative work in this area, getting more facilities for excellent research and internationalization,” says Sorokina, who left GIA in the fall of 2016 to pursue gemological research in Russia.
Aaron Palke: Applied Mineralogy and Gemstone Formation
Aaron Palke, like many scientists who decide to study Earth sciences, vividly remembers spending his summers collecting rocks.

“I became fascinated by Montana’s majestic mountain ranges and I was always raring to go collecting minerals with my father,” he says. “So naturally I decided to become a geologist.”

Palke studied mineralogy for his Ph.D. and focused on spectroscopic techniques (especially Nuclear Magnetic Resonance) to investigate the atomic-range structure of minerals during this time.

He was intrigued when he learned about GIA’s Liddicoat Postdoctoral Research Fellowship program when he was deciding on what he was going to do next.

“The program seemed like a natural choice for someone with my interests as gemology belongs essentially to the field of applied mineralogy,” he says. “My research at GIA has predominantly focused on using trace element chemistry and gemstone inclusion suites to pursue research into gemstone formation. I have been using GIA’s LA-ICP-MS facilities to analyze unusual trace elements in gem corundum, as well as analyzing inclusions in sapphires to understand the geological conditions of formation for these deposits.”

His work on melt inclusions in Yogo and other Montana sapphires, in particular, has provided some evidence for their formation through partial melting of Al-rich lower crystal rocks.

Palke credits GIA with giving him invaluable experience and access to gemological information to help advance his career. He said his time at GIA will serve him well in his new position at the University of Queensland and the Queensland Museum, where he will start later this year.

“There is probably no other place where a young scientist can have access to the resources GIA offers in terms of lab equipment, samples to work on and people with unique talents and knowledge to work with,” he says.

Learn about the requirements and application process for the Liddicoat Postdoctoral Research Fellowship or email researchcareers@gia.edu for more information. @chapter:29


Publication Year: 2006 Title: Summer 2006 Gems News International Abstract: Colored Stones and Organic Materials
            Alaskan Amber
            Update on Iridescent Andradite from Mexico
            Two Unusual Star Emeralds
            Faceted Blue Euclase from Colombia
            Color-Change Fluorite
            Herderite from Pakistan
            Jeremejevite from Myanmar and Sri Lanka
            Pink Opal from Monte Rosa, Peru
            Update on Prehnite from Australia
            Prehnite from Mali
            Natural Sapphire with Unusual Inclusions
            Sillimanite from India Resembling Moonstone
            Sphene from Afghanistan
            Uvite-Dravite Tourmaline from Morogoro, Tanzania
            Triploidite from China
            Väyrynenite from Afghanistan
Synthetics and Simulants
            Diffusion-Treated Synthetic Sapphire
Treatments
            Lead Glass–Filled Ruby Bead Necklace
Announcements
            AGTA Spectrum Awards Competition
            NAJA Conference Scholarship
Exhibits
            Upcoming GIA Museum Exhibits
            King Tut Returns

To view the full section, download the PDF above. @chapter:3


Publication Year: 1996 Title: Winter 1996 Gem News International Abstract: Diamonds
            Diamonds from Kelsey Lake, Colorado
            Update on Synthetic Diamonds in Jewelry
Colored Stones
            Natural "Carvings"
            A New Chalcedony Locality
            Cat's-Eye Emerald from Colombia
            An Update on Emerald Mining at the Muzo Mine
            A Second Sri Lankan Locality for Color-Change Garnet
Synthetics and Simulants
            Composite Tablets, Imitation "Anyolite"
            Bahamian Beauties
            An Ancient Tibetan Pendant, Represented as a Meteorite
            An Unusual Fashioned "Tricolor" Synthetic Quartz
            Another Tanzanite Imitation: Synthetic Spinel Triplets
Instrumentation
            International Conference on Raman Spectroscopy and Geology
Miscellaneous
            Synthetic Sapphire Assemblage with a Gold "Fractal" Design
            Completely Internal "Carving" of Glass

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


Publication Year: 2005 Title: Summer 2005 G&G Lab Notes Abstract: Fracture Filled Diamond with Varying Results
Large Diamond with Micro inclusions of Carbonates
Light Blue Diamond with Type IIb and IIa Zones
Natural Type Ib Diamond with Unusually High Nitrogen Content
Diamond with Unusual Laser Drill Holes
Yellowish Orange Magnesioaxinite
Cultured Pearl with Cultured-Pearl Nucleus
Dyed “Golden” Freshwater Cultured Pearls
More on Copper-Bearing Color-Change Tourmaline from Mozambique

To view the full section, download the PDF above. @chapter:35


Publication Year: - Title: 10 Diamonds That Dazzled at Auction Abstract: This 5 carat, cushion-shaped Fancy Vivid pink diamond set in platinum and 18k rose gold sold for $10.83 million at a December 2009 Christie’s auction in Hong Kong. Photo courtesy Christie’s

	The world has seen many impressive – and even historic – diamonds offered for sale at auction in recent years. The photo gallery above highlights 10 that have enthralled diamond connoisseurs with their extraordinary size, striking cut, flawless clarity, perfect color and the most alluring feature of all: rarity. These diamonds are the pinnacle of the beauty and allure of gems.

View Gallery

Read more about the growing influence of auction houses on the colored gem and diamond industry in the Spring 2013 issue of Gems & Gemology.

All of the diamonds in this photo gallery have been graded by GIA. @chapter:30


Publication Year: 2024 Title: Identification of Chromium-Bearing Red Gemstones Using Photoluminescence: A Red Musgravite Case Study Abstract: Figure 1. A 1.59 ct red musgravite. Photo by Shunsuke Nagai.

Figure 2. The PL spectrum of the red musgravite consisted of two very strong peaks at 685.7 nm (R1) and 686.8 nm (R2 or L). In the spectrum below that, its weak side peaks are expanded by multiplying the intensity by 20. They are partially similar to those of ruby (692.9 (R2) and 694.4 (R1) nm), its expanded weak side bands, and a red spinel (685.5 (R) and 687.1 (L) nm). Spectra are offset vertically for clarity.
Photoluminescence (PL) provides us with useful information to understand physical properties of gem materials and can also be used for gem identification and treatment detection. For example, a 1.59 ct red musgravite (figure 1) that had previously been examined by the Central Gem Laboratory in Japan (Z. Zhenghao et al., “A remarkable Cr-bearing red musgravite,” Journal of Gemmology, Vol. 38, No. 6, 2023, pp. 548–551) was also submitted to GIA’s Tokyo laboratory for identification. Its standard gemological properties (refractive index, specific gravity, dichroism, and UV fluorescence reaction), Raman spectrum, and ultraviolet/visible spectrum were consistent with musgravite. The chemical formula was measured as Be1.21(Mg1.95, Fe0.01, Zn0.02)Al5.86O12 by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) with a chromium concentration of 1360–1840 ppm (table 1). A PL spectrum for musgravite (figure 2) was also collected with a 532 nm laser and consisted of two strong peaks and weak side bands. Interestingly, the positions of the strong peaks were close to those caused by chromium in spinel, but the overall pattern was similar to that caused by chromium in ruby or sapphire. PL emission spectra are collected by exposing a material to strong short wavelength light, creating excited energy states in the material. These excited energy states then relax and return to a ground state by emitting light at a longer wavelength than the excitation wavelengths. The light collected during this relaxation is the PL spectrum. Trace amounts of chromium in many materials can easily enter these excited energy states and produce characteristic PL spectra in different gems such as ruby, spinel, and musgravite.

Figure 3. Polyhedral representations of the crystal structures of (A) reported musgravite, BeMg1.63Fe0.37Al6O12 (Nuber and Schmetzer, 1983); (B) typical corundum, Al2O3; and (C) normal spinel, MgAl2O4. Thin black lines depict the unit cells. The green tetrahedra are BeO4. The orange tetrahedra and octahedra are MgO4 and MgO6, respectively. The blue tetrahedra and octahedra are AlO4 and AlO6, respectively. In musgravite, the AlO6 octahedra have three types: one undistorted (Al1) and two differently distorted (Al2 and Al3).
In this report, we investigated the reasons why these PL spectra differ between red musgravite, ruby, and spinel. The two strong peaks at 685.7 and 686.8 nm of the red musgravite are referred to as zero-phonon lines (ZPLs) that do not contain the energy of “lattice vibrations,” which are the motions of atoms around their equilibrium positions. These peaks result from the transition from the lowest excited state to the ground state of three 3d orbital electrons of the Cr3+ ion replacing the Al3+ ion at the center of oxygen polyhedra, as in ruby and red spinel. The crystal structure of musgravite includes one type of AlO4 tetrahedron and three types of AlO6 octahedron: one undistorted and two differently distorted; see figure 3A, drawn using VESTA software (K. Momma and F. Izumi, “VESTA 3 for three-dimensional visualization of crystal, volumetric and morphology data,” Journal of Applied Crystallography, Vol. 44, 2011, pp. 1272–1276) and the reported crystal structure data (B. Nuber and K. Schmetzer, “Crystal structure of ternary Be-Mg-Al oxides: taaffeite, BeMg3Al8O16, and musgravite, BeMg2Al6O12,” Neues Jahrbuch fur Mineralogie, Monatshefte, 1983, pp. 393–402). The chromium PL emission is split into two strong lines, due to either the distortion of the AlO6 octahedron as in ruby and sapphire, or the occupation of multiple crystal sites by chromium. The position of the red musgravite is shorter in wavelength than in ruby and sapphire but almost equal to that of red spinel. This means the energy difference between the excited and ground states is greater than that in ruby and close to that in red spinel.
The chromium PL spectrum for musgravite shows additional small peaks at longer and shorter wavelengths, termed “phonon sidebands” and “Urbach tails,” respectively (again, see figure 2). If the intensity of the main ZPLs is a large proportion of the total luminescence intensity, it indicates that the Debye-Waller factor, representing the magnitude of atomic vibrations in a crystal structure, is small. The weak sidebands on both sides of the red musgravite indicate that the Debye-Waller factor is smaller than that of red spinel but similar to ruby.
PL spectroscopy on chromium-bearing gemstones is not only one of the most powerful tools for quick and nondestructive identification but also a means to obtain interesting physical properties of rare gemstones by comparing with the PL spectra of familiar gems. Furthermore, the difference in degree of the Debye-Waller factor may be one of the reasons why the presence or absence of heat treatment can be detected by PL in spinel (S. Saeseaw et al., “Distinguishing heated spinels from unheated natural spinels and from synthetic spinels: A short review of on-going research,” https://www.gia.edu/doc/distinguishing-heated-spinels-from-unheated-natural-spinels.pdf, April 2, 2009), but not in corundum. @chapter:10


Publication Year: 2017 Title: Book Review: Fine Jewelry Couture: Contemporary Heirlooms Abstract: By Olivier Dupon, hardcover, 256 pp., illus., publ. by Thames & Hudson, New York, 2016, US$60.00.

Fine Jewelry Couture: Contemporary Heirlooms showcases the work of 37 jewelry designers from around the world. Author Olivier Dupon has pulled together a wide assortment of design styles, including the simple, almost calligraphic work of Cristina Ortiz; the historically inspired pieces of Silvia Furmanovich; the opulent baroque jewels designed by Opposite Jewels, Wendy Yue and Mauro Felter; the perfectly framed pearls of Autore; the mechanical precision of Elie Top; the gem-encrusted confections of Nam Cho and Morphée Joaillerie; the Art Deco-like and futuristic designs of Nikos Koulis; the delicate, exquisite enamels of Ilgiz Fazulzyanov; the playful, “insectiferous” pieces of Daniela Villegas; and the elegant, timeless work of Mana Matsuzaki. In short: There’s something here for all tastes.

Each designer’s work is accompanied by a single page of biography outlining some of their personal history, inspirations, and working philosophy, along with Dupon’s comments on the work. The text is separated into two columns by a thin, elegant line tipped with the initials of the designer’s name.

Almost all sections open with an example of the designer’s sketches, or occasionally, as in the case of Jasmine Alexander, a CAD rendering. It is always a pleasure to see the notes and thought processes of designers that are only visible in their sketch work; it’s an aspect of design that is too often overlooked. It is a shame that Villegas’ drawings, which were done on black paper and would have been striking in the original, did not reproduce well in the book.

As in any book about jewelry design, photos are paramount. Most of the photos in Fine Jewelry Couture, which appear to be largely supplied by the design houses, are excellent, showing well on mostly borderless white pages. However, there are some irregularities that, once noticed, sometimes overshadow the designs themselves and mar the overall presentation.

In some photos, reflections of varying strength or drop shadows have been added. While most images float on a white background, some remain framed as photos. Although the photos are still high quality, they are noticeably different from the others in the book. Occasional advertising-like model shots—such as the one with the cockatoo on the cover—are jarring elements in a book on design.

Sometimes the jewelry is used as a design element, with the image repeated in a radial pattern; or oriented upside down and joined, by a reflection, to a right-side-up version. Rather than enhancing the power of the jewelry, the technique minimizes the impact of the designs.

In some places, there could have been a much better use of enlargements and close-ups. Top’s work, which involves mechanisms that move and rotate, would have especially been served better by showing one series of good close-ups demonstrating how the mechanisms work, rather than distant shots described as being “open” or  “closed.”

While the irregularities in the style and use of the images do not take away from the high quality of the work illustrated, they do detract from what is otherwise a delightful source book on the work of a wide range of designers. They’re unfortunate in a book on design. @chapter:16


Publication Year: - Title: Amethyst Quality Factors Abstract: This 17.53-carat amethyst displays a rich reddish purple color. - Lydia Dyer, Super Trillion Cut Amethyst gem courtesy of John Dyer & Co.

                      Amethyst has been the most-prized quartz variety for centuries. Once available only to royalty, relatively plentiful supplies have made amethyst more widely available in modern times. Today, because of its availability and affordability, amethyst is used in mass-market jewelry as well as custom designer pieces. This makes amethyst one of the world’s most popular colored gems and the most commercially important gem-quality quartz variety.

Color
The finest amethyst color is a strong reddish purple or purple with no visible color zoning. Dealers prefer strongly saturated reddish purple to dark purple, as long as the stone is not so dark that it reduces brightness. If the color is too dark, an amethyst might look black under dim lighting conditions.

	Amethyst’s color quality ranges from extremely pale to intense or very dark. - ©GIA and Tino Hammid
Any brownish or bronze-colored tints in an amethyst’s purple color, or any noticeable color zoning, lower its value dramatically. Buyers of loose amethysts view color zoning by placing the gems table-down against a white background.

	These two well-cut amethysts demonstrate the gem’s possible light-to-dark color range. - Courtesy Pala International
Many amethysts display a weak, light color or have strong zones of lighter and darker purple color. These factors lower the value of these stones.

	Color zoning is most visible when an amethyst is viewed face-down through its pavilion on a white background. It's not as visible face-up.
Heat treatment can lighten the color of very dark amethyst. Lower-quality light-colored amethyst and even light-colored quartz have been dyed to impart a purple color.

Clarity
Much of the faceted amethyst in the market is eye-clean, meaning it lacks eye-visible inclusions.  African material, especially from Zambia, can be a highly saturated raspberry color. It tends to have more inclusions than Brazilian material. However, due to its remarkable color, this is considered acceptable in a faceted stone. Eye-clean material of the same color is more valuable.

	Most faceted amethyst on the market has no eye-visible inclusions. - Courtesy Ramiro Rivero & Metals del Oriente S.R.L
Amethysts with eye-visible inclusions but attractive color are usually cut as cabochons or fashioned into beads. Cabochons and beads that display fine color and high clarity sell at a substantial premium.

Rarely, amethyst undergoes fracture-filling treatment of its surface-reaching fractures to improve apparent clarity.

Cut
Amethyst is cut into a variety of standard shapes and cutting styles. These include rounds, ovals, pears, emerald cuts, triangles, marquises, cushions, and others. Facet patterns include the classic triangular and kite-shaped facet arrangements called brilliant cuts, rows of concentric parallel facets called step cuts, and mixed cuts that combine both facet arrangements.

	Amethyst is produced in a variety of popular cuts for jewelry. - Courtesy John Miatech
Amethyst is also a very popular gem for cutting into a variety of freeform shapes. This is done by hand or by automated cutting. These so-called fantasy or designer cuts can be mass produced or created as one-of-a-kind pieces. They sometimes display concave faceting, where normally flat facets have a concave shape. Other types of cuts and carvings are also found, including carvings of animals and other objects.

	Amethyst is a popular gemstone for artistic designer cuts, even in large sizes like this 53.37-carat example. - Lydia Dyer, Amethyst Dreamscape gem courtesy of John Dyer & Co.
Carat Weight
Amethyst is available in all size ranges for setting into a variety of jewelry styles. It’s popular as a large center stone since the price per carat does not rise dramatically with larger size. Amethyst is also commonly found in calibrated cuts, which means they’re cut precisely to standard industry sizes, in all qualities.

	It’s not uncommon to see fashioned amethyst in large sizes like this 22.65-carat stone. - Courtesy Anil Gupta, Kris Gem International, Inc. @chapter:23


Publication Year: 2018 Title: Dendritic Inclusions in Cambodian Sapphire Abstract: Figure 1. Fiber-optic illumination reveals dendritic inclusions of a manganese oxide-hydroxide compound trapped within a fracture. Photomicrograph by Charuwan Khowpong; field of view 1.05 mm.

A 0.66 ct piece of blue sapphire rough from the Bo Tang Su mining area of Cambodia’s Pailin region displayed dendritic inclusions, commonly found in quartz and chalcedony but rarely seen in corundum.

These epigenetic inclusions occur as a dendritic pattern trapped along surface-reaching fractures and show higher luster than the host under reflected light. Viewed in fiber-optic light, they appear black along the fracture and the trapped unknown fluid phases (figure 1). Raman spectroscopy identified the inclusions as a compound of manganese oxide-hydroxides. The presence of these dendritic inclusions, seen trapped in a triangular fracture in figure 2, is quite unusual in sapphire from Cambodia.

Figure 2. The dendritic inclusions were trapped in a triangular fracture. Photomicrograph by Charuwan Khowpong; field of view 1.75 mm. @chapter:19


Publication Year: 2019 Title: Curved Banding in Flame-Fusion Synthetic Sapphires Abstract: Figure 1. Curved banding is easily spotted in this flame-fusion blue synthetic sapphire when illuminated with the Magilabs deep-UV fluorescence system, a short-wave UV source. Photomicrograph by E. Billie Hughes; field of view ~13 mm.

Most synthetic ruby and sapphire on the market is grown by Verneuil flame fusion. It can usually be separated from natural corundum by its distinctive curved banding, in contrast to the angular zoning seen in natural stones. Gemologists may see these features in the microscope when using darkfield or brightfield illumination. This zoning can also be seen with use of a short-wave fluorescent light, as noted in Ruby & Sapphire: A Gemologist’s Guide (R.W. Hughes et al., Lotus Publishing, Bangkok, 2017).

Figure 2. Observed with a short-wave UV light source, the sample displays curved banding, a telltale sign of a flame-fusion synthetic sapphire. Photomicrograph by E. Billie Hughes; field of view ~24.5 mm.
Recently the author noticed two excellent examples. When viewed with the Magilabs deep-UV fluorescence system (a proprietary short-wave UV source), the curved banding in the synthetics was clear (figures 1 and 2), allowing them to be easily separated from natural corundum. Gemologists using a DiamondView may see the same reaction. @chapter:12


Publication Year: 2018 Title: General Gemology and Jewelry Abstract: Gemstones and Sustainable Livelihoods: From Mines to Markets
Saleem H. Ali
Gemstones and Sustainable Development Knowledge Hub, University of Delaware, Newark
Colored gemstone supply chains are highly fragmented. The large variety of gemstones found in the trade, each with different mining and manufacturing issues and production cycles, adds to this complexity. Yet this fragmentation also creates opportunities for diffuse positive impacts in livelihood formation across the supply chain. Gemstones are predominantly mined through artisanal and small-scale mining (ASM) operations, and many of those who mine the stones remain in poverty. Furthermore, the mining is often undertaken without any mechanism for environmental remediation that can sustain livelihoods beyond the mining phase. In a sector that ranges over 50 producing countries, with a multitude of cultures, environments, and minerals, much research remains to be done on how sustainability can be improved and catalyzed between mines and markets. The benefits that could flow from the sale and beneficiation of colored gemstones remain elusive and often accrue in favor of corrupt interests that could also exacerbate security concerns in fragile states. This sector is a neglected area for research and training and has also largely eluded international mechanisms for accountability such as the United Nations–mandated Kimberley Process for diamonds.
The gemstone industry can play a vital role in sustaining livelihoods and national economies following the cessation of mining. Thailand, formerly a gemstone mining nation, has succeeded in transforming its industrial sector to become the major international hub for the processing (treatment, cutting, and polishing) and trading of gemstones within a few decades. Thailand had a long tradition in gemstone manufacturing and has successfully moved up the gemstone supply chain. The country has achieved this transformation by transmitting know-how, fostering innovation in gemstone refinement, and embodying proactive governance structures. Case lessons like these must be understood and adapted to other geographies as far as realistically possible. The beneficiation of gemstones in their country of origin is a great challenge facing countries across the globe, but especially in Africa. Despite the value and the beauty of the stones, those who mine them and those in the first steps of the value chain often live in poverty. There are encouraging developments—for example, Tanzania has successfully created a gemstone cutting and jewelry-making hub, and the Ethiopian opal sector has had some promising developments in cutting and polishing.
Thus, from mines to markets, colored gemstones provide important opportunities for contributing to development and thereby improving the brand and value of the sector for consumers. However, an integrated mechanism for linking business imperatives with social development dimensions of the sector is essential. This presentation will summarize some of the key research lessons gleaned through the Gemstones and Sustainable Development Knowledge Hub established in 2017 and the nascent educational program that is being developed through a network of international university partners on “Minerals, Materials and Society.”
Challenges of a Twenty-First Century Gem Trader
Edward Boehm
RareSource, Chattanooga, Tennessee
The gem trade looks much different than it did at the end of the last century. Previously the focus was on disclosure of synthetics and treatments, but in the last two decades it has evolved to include greater concern for sustainability, environmental conservation, and transparency in ethical sourcing. Country of origin has always played an important role in high-end gems, and this trend continues today, but the added element of traceability is changing the impact and importance of third-party verification. The country-of-origin pedigree associated with fine-quality gems from sources such as Myanmar (figure 1) and Kashmir has historically translated into desirability and higher value. However, today’s concerned consumer views a country mired in sociopolitical conflict, war, genocide, or terrorism as an undesirable source, potentially leading to boycott by not only consumers but also NGOs and large or publicly traded jewelry companies. These challenges, while daunting, should also be viewed as opportunities for the entire gem trade.

Figure 1. A gem miner holds a traditional brass plate of corundum, spinel, and peridot rough and crystals from Mogok, Myanmar. Photo by Edward Boehm.
Reputable gem dealers focus on finding quality gems sourced from reliable producers while competing for the best prices. Ethical sourcing is a main focus for many dealers, but recent sustainability and transparency requirements from larger retail chains are adding layers of responsibility that gem traders and gem trade organizations are working diligently to address. The American Gem Trade Association (AGTA), the International Colored Gemstone Association (ICA), and the World Jewellery Confederation (CIBJO) have been leaders in clear communication and disclosure to the consumer. Despite the demands of additional transparency, they face these challenges as opportunities to differentiate themselves by addressing the issues with positive and active policies. Membership in one of these organizations focused on ethical sourcing provides trade professionals with identifiable goals and guidelines to adhere to.
Modern tools to help gem traders adapt to these principles are becoming more available as demand increases. Professionals no longer have to rely only on their own gemological knowledge and contacts. Laboratory reports and now nanotechnology and blockchain tracking all provide potential third-party options for identifying and tracing the flow of gem material. Gemological laboratory reports and recent technological breakthroughs provide avenues for addressing some of the issues facing the trade, but they are not foolproof panaceas for the issues at hand. It will also take active good faith initiatives that involve the entire supply chain, from miners to retailers. As these technologies evolve and others are discovered, the trade will have even more ways to provide accurate information and confidence to consumers.
San Diego Gemstones and Gem Localities
William Larson
Pala International, Fallbrook, California
For over 125 years, San Diego County has produced famous gemstone treasures. This talk will explore the history and famous localities from the original finds of the nineteenth century, as well as the connection to Chinese Empress Dowager Cixi (1835–1908). Her enthusiasm for San Diego gems led to an estimated 90 tons of tourmaline shipped to China before 1910 and the “type” locality finds of kunzite (figure 1) and morganite.

Figure 1. This 40.34 ct pink-lavender kunzite is from Pala, California. Photo by Mia Dixon/Pala International.
Of special interest, this presentation will detail the revival of San Diego gem mining starting in the 1950s and continuing to this day by looking at the three most important districts: Ramona for spessartine garnet and topaz; Mesa Grande for tourmaline; and Pala for tourmaline, morganite, and kunzite.
The author has been directly involved with 16 gem mining projects in San Diego County since the 1960s and has locally mined 36,000 feet of underground tunnel, resulting in many successful finds. The talk will also delve into current and future challenges for gem mining in San Diego County and elsewhere, including high mining costs—involving governmental, environmental, and safety regulations—and land-use restrictions. Possible bright spots for future gem mining localities include geophysical exploration techniques and underground radar, new mining techniques, and advances in explosives.
GIA’s Field Gemology Program: A Modern Approach to Origin Determination
Wim Vertriest
GIA, Bangkok
Nowadays, origin determination is an undeniable part of gemology. For many high-end colored gemstones, country of origin is considered an important aspect that can significantly influence price. GIA realized early on that delivering trustworthy scientific studies on gemstone origin is a complex affair. It requires advanced technology, well-trained scientists, years of experience, and above all dependable reference samples.
Since the establishment of its field gemology department in 2008, GIA has built and maintained a reliable reference collection. The best way to collect samples is to cut out all intermediaries, thus removing any misinformation, and visit the mining areas in person to collect gemstones at the source, or as close to it as possible. GIA gemologists have observed and documented many of the most important ruby, sapphire, and emerald mining areas over the last decade (figure 1). Over 90 expeditions, over 20,000 reference samples—more than one million carats—have been collected.

Figure 1. Greenland ruby samples in matrix collected for GIA’s field gemology program. Photo by Wim Vertriest.
The samples collected are integrated into GIA’s colored stone reference collection. Each sample is accompanied by information detailing its sourcing, such as collection date, gem species, known treatment, previous owner details, GPS coordinates of mining and/or buying locations, and purchase price. All the data is subsequently available in an internal database that is accessible to GIA gemologists globally. When data (e.g., inclusion photos, trace-element chemistry, and spectra) are collected on the samples, they are added to the database. This becomes an important resource to GIA colored stone gemologists in every location. In a video on scientific research collections, Sir David Attenborough noted:
a research library associated with collections is almost of greater importance than the objects themselves. Unless you know where it came from exactly, and when it came from exactly, you are missing a lot of very, very important information. That information can not only come from the object itself, but from the circumstances, documentation, that should accompany every scientifically collected specimen.
(“Sir David Attenborough on Museum Collections - 360,” American Museum of Natural History, posted August 31, 2017)
While in the field, GIA team members also document the local situation. This covers mining techniques, trading activity, traditional jewelry making, gemstone history, and local gem cutting. Videos, photos, and interviews are then used to create articles and supplement course content for GIA’s educational programs. In this way, the information gathered during field expeditions becomes an invaluable resource to multiple departments within GIA and serves as a historical record of gem mining sites around the globe.
Closing the Knowledge Gap Across the Supply Chain: A Case Study of GIA and Pact’s Field Collaboration in Tanzania
Cristina Villegas
Mines to Markets Program, Pact, Washington, DC
For years, field gemologists and international development experts across disciplines have noted that colored stone supply chains are lopsided in terms of stakeholder knowledge about stone types, quality and grading, handling know-how, and what happens after the stone leaves the mine and its journey begins in the global jewelry supply chain. Those who mine the stones—typically at great personal risk—are usually the most likely to know the least about them. One stone can change a life if it is of especially high quality, while others may be “tourist grade” (local parlance for lower-value stones). Many artisanal and small-scale miners (ASM) simply do not realize the difference.
In 2017, the Gemological Institute of America and Pact, an international nonprofit social development organization with a specialty in developing and delivering ASM economic and social programs, joined forces to test a simple idea: Can a simple guidebook make a difference, and how?
The project, originally conceived by GIA distinguished research fellow Dr. James Shigley, is part of the Institute’s mission-driven effort to share information and skills throughout the gem and jewelry industry supply chain and with the public. An area in Tanzania’s Umba Valley was identified, and the program rolled out in 2017 with the Tanga chapter of the Tanzania Women Miners Association (TAWOMA; figure 1). The results were fascinating and validated the need for the guidebook. Of particular note: For every $1 the project invested in artisanal and small-scale miners, there was a $12 social return on the investment. Both male and female miners commented that they believe these changes they have experienced will last for more than five years.

Figure 1. Miriam S. Mshana, an artisanal sapphire miner, is chairwoman of the Tanga chapter of the Tanzanian Women Miners Association (TAWOMA), a field partner that facilitated access to the remote mining sites. TAWOMA comprises more than 3,000 women working across the mining sector producing gold, colored gemstones, diamonds, and industrial materials. The Tanga chapter alone has 600 members. Photo by Cristina Villegas.
This presentation will focus on how the project was implemented, monitored, and measured, and will engage the audience to help identify answers to these questions:

How can the gemological research sector, and other parts of the jewelry supply chain, help advance local economic and social development agendas in sub-Saharan Africa?
What other knowledge could be imparted in a context of low literacy? Are there other ways that learning programs could be structured to maximize impact in a given province? In other words, how can we improve in the future and also inspire others to act?

In reporting on her June 2018 trip to the region, the author will provide an update on the 2017 project participants. @chapter:38


Publication Year: - Title: An In-Depth Gemological Study of Blue Sapphires from Pailin, Cambodia Abstract: Heated faceted blue sapphires reportedly mined near Phnum Yat in Pailin, Cambodia, along with an unheated, rough trapiche-type blue sapphire crystal from Pailin. Photo: Vincent Pardieu © GIA.

The Cambodian province of Pailin is an important historical locality that has produced many fine but often small stones for over a century. Currently, just a few mechanized mining operations remain active around Pailin; artisanal miners exploit river gravels in the dry season. Although today’s production is sporadic, gems previously mined from this deposit are found in the marketplace and in jewelry.

The Pailin gem field is centered on the eroded remnants of three volcanic cones that brought ruby and sapphire to the surface as passengers—xenocrysts—in alkali-basalt magma. Due to the climate, the alkali-basalt weathers very quickly, releasing stable minerals including corundum, garnet, and zircon, which miners find in secondary deposits.

Researchers from GIA’s Bangkok laboratory analyzed 68 sapphire samples collected during field expeditions to Pailin. The samples were fashioned to optimize them for laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) chemical analysis, UV-Vis-NIR and Fourier-transform infrared (FTIR) spectroscopy, and inclusion studies using microscopy and Raman spectroscopy. Results from their study and field observations from the mining area appear in a new article titled An In-Depth Gemological Study of Blue Sapphires from Pailin, Cambodia

Pailin sapphires resemble gems from other basalt-related deposits in Thailand, Nigeria, Ethiopia, Australia, and northern Madagascar. As sapphires from these sources share similar geologic origins, it’s challenging to discriminate between them. Magnification of the Pailin sapphires revealed dense milky clouds, strong blue color zoning, and bands of minute particles, along with mineral inclusions such as pyrochlore, plagioclase feldspar, ferrocolumbite, goethite, zircon, and monazite. UV-Vis-NIR and FTIR spectra showed features typical of basalt-related sapphires. As with previous studies of basalt-hosted blue sapphires, the authors note that a combination of trace element chemistry and microscopy can help separate Pailin sapphires from samples from other localities. @chapter:3


Publication Year: 1983 Title: Engraved Gems: A Historical Perspective Abstract: Such innocuous events as the creation of the pre-gummed envelope and the modem postal system contributed to the demise of the engraved gem seal. During the thousands of years that the seal served as man's most important mark of identification, however, gem engraving reigned as one of his most significant art forms. This article traces the-history of engraved gems from primitive amulets through cylinder seals, scarabs, scaraboids, and ringstones, to the more recently introduced cameos. Also discussed is the engraving process itself, how to evaluate an engraved gem, and more recent developments in the materials and methods used to engrave gems. @chapter:26


Publication Year: 2003 Title: Summer 2003 Gem News International Abstract: Diamonds
            "Additional” Facets and Their Effect on Scintillation
Colored Stones and Organic Materials
            “Alphabet” Agates from Indonesia
            Unusual Cat’s-Eye Beryl from Brazil
            Magnetic Corundum
            Large Pink Fluorite from Pakistan
            Crystals of Color-Change Garnet from Bekily, Madagascar
            The Lion Cut for Colored Stones and Diamonds
            Tale of a Swallowed Tahitian Cultured Pearl
            Trapiche Rubies Displaying Asterism
            Cat’s-Eye Scapolite from Tanzania
            Miscellany from Tucson
Synthetics and Simulants
            Cubic Zirconia Briolettes
            A Bicolored Synthetic Diamond
Conference Reports
            SME 2003 Annual Meeting
Announcements
            Digital Geologic Map of Madagascar
            Thailand Gem Adventure
            AGTA Spectrum Awards competition
Conferences
            Jewellery World Expo 2003
            GIA GemFest USA
            IGC Postponed
            Training Courses in Heat Treating Corundum
            Geophysical Exploration for Diamonds
Diamonds—From Source to Use
            HRD Diamond Marketing Conference
            SEG Diamond and Kimberlite Course
Exhibits
            Enamels at the Newark Museum
            Art Deco at the Royal Ontario Museum
            Tourmaline at Mineralientage München

To view the full section, download the PDF above. @chapter:20


Publication Year: 2018 Title: One Natural Melee Diamond Found in Large Batch of HPHT Synthetic Melee Abstract: Figure 1. Out of a parcel of 1,102 diamond melee received at GIA’s New York lab for testing, 1,092 were identified as HPHT synthetic melee. Photo by Sood Oil (Judy) Chia and Towfiq Ahmed.

Over the last decade, the production methods used to create synthetic diamond melee have improved substantially, along with the quality of the specimens themselves. The increase in the amount of synthetic melee submitted—both disclosed and undisclosed—to GIA’s laboratories for identification has exponentially increased since GIA began offering its Melee Analysis Service in 2016. Parcels of melee are often submitted with a mixture of naturals and synthetics. Typically, a few synthetics are detected in batches of natural melee diamonds, known in the trade as “salting” (e.g., S. Eaton-Magaña and J.E. Shigley, “Observations on CVD-grown synthetic diamonds: A review,” Fall 2016 G&G, pp. 222–245).
GIA’s New York laboratory received a batch of 1,102 melee diamonds with a total weight of 9.67 carats for the melee analysis service. The tested melee ranged from 0.98 to 1.52 mm in diameter. Preliminary testing using GIA’s fully automated screening device referred 1,093 for further testing, while nine were found to be outside of the service criteria. Further analysis using detailed spectroscopic analysis confirmed 1,092 (figure 1) out of the 1,093 to be HPHT synthetics. Fourier-transform infrared (FTIR) absorption spectroscopy performed on the referred melee revealed an absorption band at approximately 2800 cm–1 from trace boron in the diamond lattice, classifying these melees as type IIb (boron-bearing), typical of HPHT synthetic diamonds. Due to the relatively high concentrations of boron, these melee diamonds showed a clear blue hue, which is very different from most of the melee diamonds we have tested.
Further examination using photoluminescence (PL) spectroscopy showed no detectable peaks of nickel, often a catalyst used to grow HPHT synthetic diamonds (e.g., Spring 2017 Lab Notes, pp. 95–96). These spectra were in fact atypical of HPHT synthetic diamonds. Distinctive HPHT growth patterns were observed in the DiamondView (figure 2) along with strong phosphorescence following exposure to short-wave UV radiation (figure 3).

Figure 2. This diamond shows characteristic growth patterns of HPHT-grown material. Photo by Stephanie Persaud.

Figure 3. These HPHT-grown synthetic diamond melee, from the parcel of 1,102 specimens, display strong phosphorescence following exposure to short-wave UV radiation. Photo by Sood Oil (Judy) Chia and Towfiq Ahmed.
One sample out of 1,093 was confirmed as a natural diamond. Infrared absorption spectroscopy indicated this stone was type Ia, with a hydrogen peak at 3107 cm–1. DiamondView imaging displayed a typical blue fluorescence and no detectable phosphorescence, both typical for a natural type Ia diamond.
It is interesting to note that only one natural was found in this parcel of melee. This has been the largest percentage of undisclosed synthetic melee that GIA has seen. The majority of the HPHT synthetic melee had no detectable traces of Ni, demonstrating the importance of advanced testing to identify these melees. @chapter:15