Publication Year: 2021 Title: Biogenic Carbon in Pink Corundum from Southern West Greenland Abstract: Figure 1. Field relationship of aluminum-rich metasedimentary rocks with ultramafic rocks at the Maniitsoq pink corundum occurrence in Greenland. Corundum is found along the boundary between these two rock types. Photo by Kristoffer Szilas.
Some of the oldest ruby is found in the southern part of West Greenland. Although the most famous locality is the Aappaluttoq deposit—where corundum is hosted by igneous rocks (N. Keulen et al., “Formation, origin and geographic typing of corundum (ruby and pink sapphire) from the Fiskenæsset complex, Greenland,” Lithos, Vol. 366–367, 2020, article no. 105536)—several smaller occurrences are found throughout the region. A number of these smaller occurrences are hosted by metamorphosed sedimentary rocks that were tectonically interleaved with ultramafic rocks (figure 1). Fluid-assisted movement of silica from the metasedimentary rocks to the ultramafic rocks and reverse movement of minor amounts of chromium during metamorphism have been proposed to cause the chemical conditions necessary for ruby growth.

Figure 2. Pink corundum from the Maniitsoq locality containing a macroscopic inclusion of graphite. Photo by Kristoffer Szilas.
Pink corundum from these smaller occurrences contains various types of mineral inclusions, most notably rutile and graphite (figure 2). Two recent studies investigated these rocks with the goals of dating the absolute timing of corundum growth, understanding the corundum formation mechanisms, and determining the origin of graphite (V. van Hinsberg et al., “The corundum conundrum: Constraining the compositions of fluids involved in ruby formation in metamorphic melanges of ultramafic and aluminous rocks,” Chemical Geology, Vol. 571, 2021, article no. 120180; C. Yakymchuk et al., “Corundum (ruby) growth during the final assembly of the Archean North Atlantic Craton, southern West Greenland,” Ore Geology Reviews, Vol. 138, 2021, article no. 104417). Samples were collected from an occurrence near the town of Maniitsoq and from a second occurrence on Storø Island to the northeast of Greenland’s capital, Nuuk.
Rutile inclusions are about 2.5 billion years old at both localities, based on uranium–lead geochronology. However, the pink corundum may be slightly older than this, given that the isotopic clock in rutile may only start sometime on the post-growth cooling history. Nevertheless, this constrains the timing of corundum growth during the final stabilization of the continental crust in the region.
This research also analyzed the carbon isotope composition of graphite to determine its origin. In general, biogenic activity modifies carbon isotopes; living organisms preferentially incorporate the lighter isotope (12C) compared with the heavier isotope (13C). Graphite from the Storø Island location was very enriched in the lighter isotope and was interpreted as a bona fide organic signature, which suggests that the graphitic carbon was originally part of a living organism. Graphite from the Maniitsoq pink corundum locality was less enriched in the lighter carbon isotope, but the isotope signature was still most consistent with a biogenic origin. Although the presence of carbon of biogenic origin is not surprising given the sedimentary nature of the host rocks, the research team modeled the chemical conditions necessary for corundum growth and suggested that the presence of graphite created the conditions in the rocks that facilitated corundum formation at the imposed depths and temperatures of metamorphism.
Although the recognition of biogenic carbon in the form of graphite in pink corundum occurrences is based on a limited number of samples, future work should be able to determine how widespread this association is in southern West Greenland. In addition, in situ analysis of carbon in graphite inclusions using secondary ion mass spectrometry would help further test the hypothesis of a biogenic origin of graphite in 2.5 billion-year-old pink corundum. @chapter:4


Publication Year: 2015 Title: Cat’s-Eye Calcite from Pakistan Abstract: Figure 1. This 57.60 ct calcite from Pakistan shows a cat’s-eye. Photo by Jaroslav Hyršl.

              Cat’s-eye calcites have been sold at auctions and gem shows for some years, but a gemological description of the material has not been published. Low-quality cat’s-eye calcites do exist, such as blue calcites from Mogok, Myanmar, but their chatoyancy is weak. It was very surprising, therefore, to see sharp chatoyancy on the beautiful calcite cabochon in figure 1.

The stone, purchased during the Tucson shows in February 2015, came from the Baluchistan province of Pakistan. It weighed 57.60 ct and measured 25.0 × 24.6 × 12.3 mm. It was light green and translucent, without eye-visible inclusions. The spot RI ranged from 1.48 to 1.66, and when rotated the cabochon showed a strong “blink” typical for carbonates. This is significant because the stone resembled chrysoprase; without the rotation, the measured RI in a given position might also approximate that of chrysoprase. There were no lines in the visible spectrum, the stone was inert under UV light, and its specific gravity was 2.72. Viewed in the polariscope, it remained bright, indicating a doubly refractive aggregate. Strong banding (figure 2) was present in the direction of chatoyancy, but the bands were inclined at about 20° angles. The bands were approximately 0.7 mm thick.

Figure 2. Banding in chatoyant calcite from Pakistan, as seen through the bottom of the cabochon. Photo by Jaroslav Hyršl.
Only at 40× magnification did the cause of the chatoyancy become apparent. Numerous tiny needles perpendicular to the chatoyancy were likely evidence of a columnar to needle-like texture. Other than the chatoyancy, this specimen is similar in appearance to the green and orangy yellow calcites from Pakistan that were described in the Fall 2012 GNI section (pp. 217–218). It is the opinion of both the seller and the author that this calcite is from the same locality. @chapter:13


Publication Year: 2017 Title: A Synthetic Diamond Overgrowth on a Natural Diamond Abstract: Figure 1. This 0.33 ct Fancy blue diamond was confirmed to be a composite of CVD synthetic type IIb diamond overgrowth on a natural type Ia substrate. Photo by Sood Oil (Judy) Chia.

Nitrogen is the most abundant defect in natural diamonds. It can be observed as single substitutional atoms or in aggregate forms. Boron, on the other hand, is a rare impurity in natural diamonds. It is very unusual to see both nitrogen and boron defects in a single diamond. GIA’s New York laboratory recently encountered this in a 0.33 ct diamond graded Fancy blue (figure 1).

The infrared spectrum revealed something very unusual: a mixed type Ia and IIb diamond (figure 2). It also showed a platelet peak at 1367 cm–1 and a hydrogen peak at 3107 cm–1. Mixed type Ia and IIb diamond occurs very rarely in nature; one was previously reported in Gems & Gemology (Spring 2009 Lab Notes, pp. 55–57). Nitrogen aggregation in this diamond was much higher, however. DiamondView images showed bluish green fluorescence in the face-up view and blue fluorescence in the face-down view (again, see figure 2). Detailed analysis using the DiamondView revealed a yellowish green fluorescence zone at the top of the crown with a sharp boundary in the crown facets (figure 2). PL spectra collected from the table and at the boundary in the crown facets showed emissions from SiV– defects at 736.3 and 736.9 nm.

Figure 2. The mid-IR spectrum on the left revealed peaks for nitrogen aggregates and boron defects, along with a platelet peak at 1367 cm–1 and hydrogen peak at 3107 cm–1. DiamondView imaging showed bluish green fluorescence in the face-up view (top right) and blue fluorescence in the face-down view (center right). The yellowish green fluorescent top layer was visible in a DiamondView image (bottom right). Images by Kyaw Soe Moe.

Although SiV– defects can be observed in a natural diamond, the combination of SiV– defects, a sharp boundary, yellowish green fluorescence, and phosphorescence suggested that the top layer was CVD synthetic diamond. The bottom diamond showed blue fluorescence but no phosphorescence in the DiamondView, consistent with natural type Ia diamond. A distinct boundary line was observed along the interface layer on the crown facets (figure 3). The presence of the overgrowth layer was also clearly revealed through inspection with a variable pressure electron microscope set up to detect both secondary electron and panchromatic cathodoluminescence (CL) emission from the sample, providing topographical and compositional information (again, see figure 3). A distinct interface was visible through the pavilion in reflected light using a fiber-optic light source. A cloud-like inclusion, trapped at the interface layer, was also observed, as well as a dark needle located at or near the interface (figure 3). A small stress halo and a natural surface could be observed in the bottom diamond. The strain pattern throughout the pavilion was consistent with natural type Ia diamond. The quality of a CVD synthetic depends on the crystallographic orientation and temperature of the seed crystal or substrate during growth. CVD synthetic diamond films have been grown on natural diamond substrates since the early 1960s (W.G. Eversole, U.S. patents 3030187 and 3030188, 1962). Methane and other carbon-containing gases were used, but graphite was deposited along with the CVD synthetic layers. In 1993, CVD synthetic layers were successfully grown on natural type IIa and Ia diamond substrates (see B.G. Yacobi et al., “Preferential incorporation of defects in monocrystalline diamond films,” Diamond and Related Materials, Vol. 2, No. 2–4, 1993, pp. 92–99). They applied a mixture of CH4 and H2 at 80 torr in a microwave plasma-assisted CVD system. Reaction between CH4 and H2 produced H atoms, which maintained an sp3-bonded surface and prevented graphitization. The temperature applied to the natural diamond substrate during the CVD growth process of the sample we studied was relatively low, as suggested by the absence of single substitutional nitrogen atoms (Ns0). It is also in agreement with Yacobi (1993), who applied temperatures of 880°C for CVD growth on type Ia {100} diamond substrates and 1200°C for type Ia {111} diamond substrates. Deposition of a boron-doped CVD synthetic film of <10 microns on a natural gem-quality diamond was reported in 2005 (Summer 2014 Lab Notes, p. 152); however, spectroscopic analysis did not show boron and SiV– defects.

Figure 3. Left: A distinct boundary line indicating an interface (marked with arrows) was seen under the microscope. A dark needle inclusion is located at or near the interface (near the center of the image). Photo by Kyaw Soe Moe; field of view 1.95 mm. Center: An electron microscope image combining secondary electron and cathodoluminescence emissions reveals the presence of an overgrowth layer. Photo by Ulrika D’Haenens-Johansson. Right: The CVD synthetic layer is approximately 80 microns thick.
Based on the growth pattern of the natural diamond, it is clear that the type IIb CVD diamond was produced in or very close to {100} orientation. The natural diamond substrate showed no observable inclusions except for a very small stress halo. The thickness of the CVD overgrowth layer was approximately 80 microns (again, see figure 3). FTIR spectroscopy is a bulk analysis, making it very hard to measure and separate IR spectra between a thin CVD layer on top and a thick diamond substrate. However, the fluorescence and phosphorescence reactions suggest that the top synthetic layer contained boron (e.g., boron-doped CVD synthetic) and the bottom diamond contained nitrogen aggregates. The thin layer of type IIb CVD synthetic diamond on the top of this stone effectively introduced Fancy blue color when viewed from its table.

This synthetic overgrowth on a natural diamond with a Fancy color grade is the first GIA has seen. Identification of colored diamonds should be performed very carefully by looking for unusual characteristics, such as a straight boundary line associated with an interface plane, and fluorescence zones with sharp edges in DiamondView images. Examination of this fancy-color composite diamond indicated that similar challenges could exist for colorless and near-colorless diamonds. @chapter:15


Publication Year: 2014 Title: Letters: Analysis of Three-Phase Inclusions in Emerald Abstract: In the Summer 2014 issue of Gems & Gemology (pp. 114–132), Sudarat Saeseaw and her colleagues from GIA’s Bangkok laboratory presented a study dealing with three-phase inclusions, absorption spectra, and trace-element analyses for origin determination of emeralds. Examples of three-phase inclusions were presented for samples from Zambia (the Musakashi and Kafubu deposits), the Panjshir Valley in Afghanistan, Davdar in China, and several Colombian localities (Coscuez, Muzo, Peñas Blancas, La Pita, and Chivor).

Unfortunately, the authors did not mention in their literature overview or in their discussion the various other emerald deposits which have supplied samples with three-phase inclusions. These include Nigeria (Henn and Bank, 1991); Capoeirana in Minas Gerais, Brazil (Epstein, 1989); Eastern Himalaya (Niedermayr et al., 2002); the Maria deposit in Mozambique (Vapnik and Moroz, 2002); the Lened emerald prospect in the Northwest Territories of Canada (Marshall et al., 2004); Malipo County in the Yunnan province of China (Huong, 2008); and Eidsvoll in Norway (Rondeau et al., 2008). While some of these occurrences might be of academic interest only, others such as Nigeria, Brazil, and Mozambique have supplied emeralds of gem quality to the market. These localities cannot be ignored in a research paper on origin determination and three-phase inclusions.

Although the chemical data presented in Saeseaw et al.’s table 2 were calibrated using the theoretical Si content of beryl as an internal standard, the laser ablation data show such a wide variation for the main elements that it is impossible to calculate a formula for the samples (compare, for example, the overview of chemical data for emeralds from various sources by Groat et al., 2008). Nevertheless, the authors were able to group their samples into five different categories and to present representative absorption spectra in the UV-Vis-NIR range for one sample from each group. Confusingly, four of the five spectra are labeled “E || c”, but polarized spectra are given for the ordinary ray (ω, equivalent to E ⊥ c) and the extraordinary ray (ε, equivalent to E || c), which is impossible for a primary beam with E || c.

In the spectra of several samples with low iron contents, Saeseaw et al. measured some weak to moderate absorption bands in the near infrared at 810 nm, which were assigned to bivalent iron. In the spectra of samples from Kafubu, Zambia, with higher iron contents, an additional strong absorption band at 620 nm was also assigned to Fe2+. These assignments fail to acknowledge numerous research papers dealing with the role of iron in the beryl structure, which has been established for decades. With regard to the bands mentioned at 810 nm, it has been shown that the intensities of the different iron bands in the near infrared with polarization || or ⊥ c are not directly correlated. Consequently, these absorption bands have been assigned to two different types or coordination states of iron, most likely to Fe2+ in tetrahedral and octahedral sites of the beryl lattice. Concerning the band noted at 620 nm, it has likewise been demonstrated that the intensities of the iron-related absorption bands in the near infrared are not directly correlated with the intensity of this broad band, polarized || c in the visible region around 620 nm (figure 1). Thus the broad absorption from about 600 to 750 nm in the spectra of Kafubu emeralds has been assigned to Fe2+/Fe3+ charge transfer (Schmetzer and Bank, 1981). This indicates that emeralds from Zambia’s Miku-Kafubu mining range contain, in addition to chromium as the dominant color-causing trace element, a distinct aquamarine component (figure 2). The aquamarine component is responsible for a color shift and pleochroism, especially of the color || c from green or bluish green in “ordinary” emeralds to greenish blue or blue in samples with such an aquamarine component. Emeralds from multiple sources show this phenomenon and similar absorption spectra (e.g., Schmetzer, 1988; Henn and Bank, 1991; Henn, 1992; Hänni, 1992; Moroz et al., 1999).

Figure 1. Polarized absorption spectra of emeralds from different sources. Sample A from Chivor, Colombia, represents a typical chromium-vanadium emerald spectrum without distinct iron absorption bands. Sample B from Jos, Nigeria, represents a typical chromium-vanadium emerald spectrum with an Fe2+-related absorption band (3) in the near infrared and two Fe3+ bands in the bluish violet and ultraviolet range (17, 20). Samples C (Ankadilalana, Madagascar), D (Santa Terezinha de Goiás, Brazil), and E (Miku, Zambia) represent the superimposed spectra of chromium-vanadium emeralds with distinct aquamarine components of variable intensities, wherein the aquamarine spectrum consists of two absorption bands in the near infrared (2, 3), iron bands in the bluish violet and ultraviolet (17, 20) regions, and a broad polarized absorption in the red (5). After Schmetzer (1988).

Figure 2. Polarized absorption spectra of emeralds from two different sources and an
aquamarine. Sample A, an emerald from Muzo, Colombia, displays a typical chromium-vanadium emerald spectrum without distinct iron absorption bands. Sample B, an emerald from Miku, Zambia, shows the superimposed spectra of chromium-vanadium emerald with a distinct aquamarine component. Sample C, an aquamarine from Tongafino, Madagascar,
displays a typical aquamarine spectrum with two absorption bands in the near infrared (2, 3), iron bands in the bluish violet and ultraviolet regions (17, 20), and a broad polarized absorption in the red (5). After Schmetzer and Bank (1981).
Another frequently occurring trace element in natural emeralds from various localities is vanadium. According to Saeseaw et al., vanadium absorption bands are observed in natural vanadium-bearing emeralds in the ω spectrum (equivalent to E ⊥ c) at 400 nm and in the ε spectrum (equivalent to E || c) at 654 nm. Natural vanadium-bearing, chromium-free emeralds are rare but have been documented (from Salininha, Brazil, for instance). These also reveal distinct amounts of iron, and the various bands in the absorption spectrum of this type of beryl have been assigned to vanadium and iron (Wood and Nassau, 1968). Nearly iron- and chromium-free samples have been grown synthetically; they are commercially available from Biron in Perth, Australia (Schwarz and Schmetzer, 2001), and from Tairus in Novosibirsk, Russia (Schmetzer et al., 2006; see also the summary of references describing vanadium-related absorption spectra in that paper).

Without going into the details of these spectra or discussing the possible presence of vanadium in valence states other than V3+ (see Hutton et al., 1991), it is evident that the spectrum of trivalent vanadium in beryl consists of two strong absorption bands in the visible range (figure 3). Parts of these absorption bands are split into different maxima or show various shoulders, but both absorption maxima are, in contrast to the spectroscopic characteristics noted by Saeseaw et al., present in both polarization directions, parallel and perpendicular to the c-axis.

Natural beryl from most sources reveals some traces of both vanadium and chromium. The ratio of vanadium to chromium varies considerably, especially in samples from the Colombian emerald deposits (Schwarz, 1992). Because the absorption bands of these two trace elements are found in the same spectral range, vanadium- and chromium-related absorptions are superimposed in the spectra of emeralds containing both trace elements. As a result, the different vanadium and chromium maxima are not shown individually (figure 3).

Figure 3. Polarized absorption spectra of two natural Colombian emeralds and a synthetic vanadium-bearing emerald. Sample A from Colombia shows distinctly higher chromium than vanadium contents, Cr V. Sample B shows almost equal amounts of vanadium and chromium, V ≈ Cr. Sample C, representing a Biron hydrothermally grown emerald, shows distinctly higher vanadium than chromium contents, V >> Cr. After Schwarz and Schmetzer (2001).
The vanadium-chromium ratio in natural emeralds can be approximated from the intensity of the spin-forbidden sharp chromium bands in the 600–700 nm range of the vanadium-chromium spectra. These bands are stronger in samples with distinctly higher chromium than vanadium contents (figure 3A) and become weaker in samples with almost equal chromium and vanadium contents (figure 3B). Furthermore, in samples with distinct vanadium contents, the strong absorption band in the bluish violet range at about 430 nm displays a shoulder in the ultraviolet near 395 nm, observed in both polarization directions, || or ⊥ c (see figures 3B and 3C).

Emeralds from Davdar, China, reveal appreciable amounts of vanadium and chromium (Schwarz and Pardieu, 2009), and they can be distinctly zoned, with a wide variation of vanadium and chromium contents in various growth sectors of the same crystal (Marshall et al., 2012). In Saeseaw et al.’s spectrum for an emerald from Davdar, the sharp chromium lines are distinct and the shoulder in the UV is weak (in the spectrum ⊥ c) or almost invisible (in the spectrum || c), although a vanadium to chromium ratio of about 4:1 is reported for that sample. With such a high ratio, the sharp chromium lines should be noticeably weaker and the vanadium shoulder in the UV should be more intense. Therefore, it would seem desirable to control the chemical analyses obtained by laser ablation, especially for determining the concentration of vanadium and chromium, with other non-destructive methods such as X-ray fluorescence or electron microprobe.

Dr. Karl Schmetzer
Petershausen, Germany
September 3, 2014
Reply
We appreciate the opportunity to answer Dr. Schmetzer’s interesting and informed response to our article. First of all, he has provided several helpful bibliographic references about multiphase inclusions in emeralds from a variety of geographic sources. Nevertheless, the stated purpose of our study was to compare the inclusions in emeralds from the new deposit in Musakashi (Zambia) with those from different sources in our Bangkok reference collection using standard laboratory equipment. In that regard, our article can be considered a preliminary study rather than the final word on the subject.

Dr. Schmetzer goes on to ask about our system of labeling wafers for spectroscopy. In our article, “E ∥ c” means that the wafer plane is parallel to the c-axis, which enables us to collect both ω and ε rays.

Regarding Dr. Schmetzer’s concerns about UV-Vis spectra, we focused our study on inclusions. Nevertheless, we provided some significant spectroscopic and chemical data, as these techniques are very important in emerald origin determination. Dr. Schmetzer’s specific inquiries about UV-Vis spectra and iron and vanadium contributions are beyond the scope of our article. To understand clearly how impurity affects color in beryl, we would have needed to test known samples of beryl doped with different elements. This would have taken our study in an altogether different direction.

Lastly, Dr. Schmetzer points out our inability to correlate the LA-ICP-MS chemical data with the UV-Vis spectra for one emerald from the Davdar deposit. He suggests controlling our LA-ICP-MS data with other techniques. In our opinion, the lack of correlation has more to do with the fact that these different techniques are not analyzing the same thing: UV-Vis spectroscopy is a bulk analysis, while LA-ICP-MS is a spot analysis (40 microns in diameter in this study). As a result, UV-Vis spectroscopy and LA-ICP-MS usually do not provide a perfect correlation when it comes to inhomogeneous natural emeralds with color zoning and inclusions, such as the emerald from Davdar.

Again, we thank Dr. Schmetzer for his comments and assure him that GIA plans to obtain and study more emeralds from different mining areas, to further our lab’s capacity to provide accurate origin determination reports.

Sudarat Saeseaw, Vincent Pardieu, and Supharat Sangsawong
GIA, Bangkok @chapter:8


Publication Year: 1997 Title: Benitoite from the New Idria District, San Benito County, California Abstract: Commercial quantities of gem-quality benitoite are known from a single location in the world, the Benitoite Gem mine in the New Idria district of San Benito County, California. A barium titanium silicate, benitoite is typically colorless to blue, and is noteworthy for its high refractive indices, moderate birefringence, and strong dispersion. Benitoite occurs in altered blue schist within serpentinite. The gem crystals formed within fractures as a result of the alteration of blue schist by hydrothermal fluids derived from the regional metamorphism of the serpentinite. An extension of the historic deposit at the Benitoite Gem mine was discovered in the spring of 1997, which should contribute to continued stability in price and supply. The gemological properties of benitoite readily identify it from similar-appearing gems. @chapter:5


Publication Year: 2015 Title: Red Heart Inclusion in Diamond Abstract: A unique expression of romance: Breaking the surface of this 2.00 ct diamond is a red heart-shaped inclusion. Photomicrograph by Nathan Renfro; field of view 1.58 mm.

	Diamonds, like colored gemstones, contain a variety of interesting inclusions. Although some would call them flaws, I prefer to think of them as Mother Nature’s artwork or fingerprint. I have seen inclusions resembling angels and animals of all sorts, some requiring more imagination than others. It is fascinating to think of what might have been captured inside a diamond more than two billion years ago.

	The 2.00 ct round brilliant diamond shown in figure 2 has I color, I1 clarity, and a wonderful cut. But its most remarkable feature is a red heart-shaped inclusion, identified as pyrope garnet based on microscopic examination by GIA’s Carlsbad laboratory. The inclusion is not visible to the eye but jumps out at 10× magnification. It measures approximately 140 microns across where it is exposed at the table facet. The inclusion is much larger and extends along almost half of the image frame, but the reflective interface makes it difficult to see the underlying garnet. We only see the pink color where the inclusion breaks the surface and the mirror-like interface has been removed.

	With the combination of the red heart and diamond, both universal symbols of love, this is a one-of-a-kind gem. We have named it the Forsythe diamond and plan to auction it around Valentine’s Day 2016, in keeping with the theme of romance, and part of the proceeds will go toward a local charity. How lucky are we to be able to work with beautiful gemstones containing hidden secrets just waiting to be unlocked every day. @chapter:29


Publication Year: 2014 Title: Natural Pipi Pearls from Tahiti Abstract: Figure 1. This parcel of rare natural pipi pearls was collected from French Polynesia. Note the exceptional golden pearl in the front with a diameter of 9.6 mm, believed to be the largest recorded pipi pearl. Courtesy of Bruno Arrighi/Croissy Pacific. Photo by Olivier Segura.

              Recently, the Laboratoire Français de Gemmologie (LFG) received a parcel of nearly 100 pearls submitted as natural pearls from Pinctada maculata. The owner (Bruno Arrighi, Croissy Pacific) specified that he had personally collected the parcel in French Polynesia during the past year (figure 1).

Pinctada maculata is a bivalve mollusk (figure 2) found in the Pacific Ocean, particularly near French Polynesia and the Cook Islands, that may produce rare “poe pipi” (better known as “pipi”) pearls. There were several unsuccessful attempts in the 1950s to produce cultured pipi specimens. Today, all such pearls are considered natural.

	Figure 2. The two valves of a typical Pinctada maculata shell specimen (interior and exterior view). Photo by Olivier Segura.
Different techniques are used to find the pearls. In one method, divers pick the largest shells of Pinctada maculata, then leave the shells on the beach in buckets full of salt water to putrefy. Three days later, the shells are selected and only the valves with blisters are kept. Deep in the bucket, one may occasionally find a few natural pearls. Kakaro (in the Paumotuan language) is considered the oldest technique for obtaining pipi pearls. During the dive, the largest shells are opened directly underwater to locate pearls.

Most pipi pearls range from orange to cream, gray, and white, but the typical and most sought-after color is a deep golden color. The size of the pearls generally ranges from 1 to 4 mm. The pearl in the forefront of figure 1 has one of the best golden colors possible. It is an exceptionally large specimen measuring 9.6 mm in diameter, which the contributors believe to be the largest size documented for a pipi pearl.

Microradiography reveals internal structures typical for natural pearls: onion-like stacking of aragonite layers possibly containing a calcitic core. Although Raman scattering, UV-visible reflectance, or UV luminescence spectrometry have helped identify the mollusk species in some cases, preliminary results with Pinctada maculata are still not conclusive. Hence, it is not possible to identify with certainty the exact mollusk from which these pearls came. @chapter:14


Publication Year: 2023 Title: Strategies to Win Over Jewelry Buyers in the U.S. Market. Abstract: Strategies to Captivate Jewelry Buyers in the U.S. Market
Data from Mastercard SpendingPulse, compiled by the Mastercard Economics Institute, shows that retail sales in stores and online in the United States in January expanded by 8.8% compared to the same period last year. The driving force behind consumer spending was notably in the jewelry and restaurant service sectors, which experienced significant growth.

Jewelry sales in the United States in January 2566 increased by 6.5% compared to the previous year, primarily due to consumer spending on jewelry for the Valentine's Day festival. A survey of American consumers aged 18 and above, totaling 7,728 individuals, revealed that consumers planned to purchase jewelry as gifts for Valentine's Day, averaging about $45.75 per person.

Although jewelry sales in December 2565 decreased by 5.4% compared to the previous year, it was considered a minor decline. This is because jewelry sales in December 2564 had expanded significantly by 32% compared to the year before. Retail jewelry trade figures for the United States, collected by the U.S. Department of Commerce, had a value of $91.5 billion in 2565, increasing by 5.9% compared to the previous year. This growth was driven by consumer demand for jewelry for various activities such as weddings, social events, and tourism.

Michelle Meyer, Head Economist of the Mastercard Economics Institute for the North American region, stated that the main factors driving consumer purchasing decisions in the United States are income and therefore, labor market strength is a significant support factor for consumer purchasing power in the United States. The growth in retail figures in January reflects consumer confidence in the job market, which is developing positively, and wages that have seen an increase
The unemployment rate in the United States in January 2566 was at a record low of 3.4% in 54 years. Meanwhile, the job market saw an increase of 517,000 jobs, the highest in six months. The trend of jewelry demand in the United States, gathered from leading brands, indicates that popular jewelry items this year include metal jewelry such as chains and necklaces adorned with a variety of natural pearls, sapphires, and opals. Second-hand jewelry and watches, classic-designed earrings with gold plating, men-inspired jewelry like multi-strand necklaces, cufflinks, and synthetic diamond jewelry, are also popular.

Furthermore, men's jewelry wearing has gained acceptance and popularity, contributing significantly to the expanding jewelry market. Popular men's jewelry includes chain necklaces, pendant necklaces, rings with logos or engravings, and pearl necklaces, among others. According to research by Euromonitor International, the men's jewelry market in the United States in 2564 was valued at approximately $6.5 billion, increasing by 17% compared to the previous year and almost 4% compared to 2562. This continuous growth has been ongoing since 2558 and is expected to continue in the future.

This opportunity has pushed online retailers and various brands to penetrate the growing and promising men's jewelry market. It has become increasingly popular among celebrities, athletes, and online influencers, leading jewelry brands to develop more men's jewelry lines and making jewelry more essential in daily life for all genders and ages. The distribution of jewelry products in the United States is increasingly focused on expanding into e-commerce channels
In addition to online sales, there are other supplementary services to boost sales, such as providing product information through social media and consulting services for jewelry selection by gemologists using virtual reality technology to create experiences for buyers. Besides online sales, alternative sales formats are also popular and expected to play a more significant role this year, such as organizing pop-ups, trunk sales, and selling through art gallery exhibitions.

According to data from IBIS World, online jewelry sales in the United States market in 2565 were valued at $8.69 billion, a decrease of 1.58% compared to the previous year. Analysts believe that the online jewelry market may contract in 2566 as consumers are shifting their interest towards new purchasing patterns, particularly focusing more on e-commerce platforms. Popular e-commerce platforms in the United States, such as Amazon with approximately 2 billion visitors (amazon.com), eBay with around 688.9 million visitors (ebay.com), Walmart with about 388.8 million visitors (walmart.com), Etsy with approximately 238.4 million visitors (etsy.com), among others, are gaining more popularity.

Online auction platforms in the United States, such as 1stdibs (1stdibs.com), Worthy (worthy.com), and Bidsquare (bidsquare.com), also offer opportunities for Thai jewelry and gemstones in the United States market
From discussions with importers in the United States, it was found that Thai jewelry products (OEM) still have good opportunities for market expansion in the United States. This is due to the availability of raw materials, a wide range of design options, and standardized craftsmanship, which continue to attract importers to produce goods. The trade war between China and the United States has led importers to increasingly import products from Thailand to reduce long-term risks. Furthermore, Thailand possesses skills and techniques in traditional gemstone setting that align with market demands, especially in the Antique Style market segment, which is growing significantly and highly desired by consumers.

With the quality and reputation of Thailand, Thai products have the opportunity to establish their own brands in the Luxury Market through participation in luxury exhibitions such as The Couture (Las Vegas) and Luxury JCK (Las Vegas) or leveraging key influential networks. Building such brands should be a long-term strategy to create recognition and perception that Thai products are of high quality and designed with top standards.

The diversity of consumer groups in the United States market also opens opportunities for niche market designers, especially in contemporary jewelry that is distinctive and has brand potential for market expansion. Utilizing museum channels to reach high-end customers, celebrities, and Hollywood actors with high purchasing power can further expand the market.

Designers should pay attention to designing products for holiday gifts as holiday seasons are periods of high sales and consumers have a demand for unique products. Additionally, focusing on ethics, sustainability, and environmental conservation could be another important strategy to boost confidence among Gen Millennial consumers that the company's products are socially responsible, encouraging them to buy more Thai jewelry products
 @chapter:27


Publication Year: 1985 Title: Spring 1985 G&G Book Reviews Abstract: “Diamond”
By Gordon Davies, 255 pp., illus., publ. by Adam Hilger Ltd., Bristol, England, 1984. US $28.00

“Gemstone Enhancement”
By Kurt Nassau, 221 pp., illus., publ. by Butterworths, London, England, 1984. US $34.95

To view the full section, download the PDF above. @chapter:29


Publication Year: 2015 Title: Thai-Myanmar Petrified Woods Abstract: Figure 1. Left: Petrified woods are carved and sold as ornamental gem materials, such as these specimens from the Mae Sai market near the Thai-Myanmar border. Right: A few of the cabochons from this study. Photos by Seriwat Saminpanya.

Petrified woods (figure 1, left) have long been used as a gem and ornamental material due to their beauty, luster, durability, and relative rarity. Certain minerals (mainly quartz, opal, or moganite) crystallize or precipitate in the hollow cavities and cells of the woods in a fossilization process. Fossil trading is government regulated in some countries, and gemologists should know the useful identifying characteristics of petrified woods, which can be misidentified as jasper and agate. With this in mind, the author examined Thai-Myanmar petrified wood samples, fashioned as cabochons (figure 1, right), for gemological characterization.

More than 100 Thai samples were collected from the four localities shown in figure 2: Tak, in Ban Tak-Oke (TAK); Khon Kaen, in Ban Hin Khao (BHK); Chaiyaphum, in Noen Sa Nga (CYP); and Nakhonratchasima, in Kroke Duan Ha (KDH). About 100 Burmese samples were donated by carvers from Mae Sai in Chiang Rai province (MYR), near the border of Thailand and Myanmar. Thai specimens were collected from either Quaternary gravel beds of fluvial deposits or the high-terrace sands and gravels of paleorivers. Tektite grains found in the sediments date back 700,000 to 900,000 years (P. W. Haines et al., “Flood deposits penecontemporaneous with ~0.8 Ma tektite fall in NE Thailand: Impact-induced environmental effects?” Earth and Planetary Science Letters, Vol. 225, 2004, pp. 19–28).

Thirty-eight samples (all but seven from Thailand) were tested by standard gemological methods, Raman spectroscopy, and X-ray diffraction (XRD). Thirty-seven of these came from dicotyledonous plants, indicated by vascular bundles concentrated in an outer ring of active growth. Periods of slow (winter) and fast (summer) growth create the growth rings in the trunk. One sample came from a palm tree, and had vascular bundles dispersed throughout the trunk.

Figure 2. A map showing the localities in Thailand and Myanmar where the petrified wood
samples originated. Adapted from Saminpanya and Sutherland, 2013.
The rough surfaces may have been altered and stained by soil or iron oxides, resulting in black, brown, cream, white, and red coloration. Colorless areas and different shades of brown, black, gray, white, cream, yellow, orange, and red appeared below the surface. Some samples exhibited color banding. Most Thai samples were opaque or nearly opaque; those from Myanmar were translucent and lighter in tone. The surfaces showed varying degrees of luster and fracturing. Refractive indices ranged from 1.425 to 1.543 (tested at the flat polished base of the cabochon), and specific gravities ranged from 1.963 to 2.616. Most samples fluoresced weak to moderate chalky white under long-wave UV, but some were inert or showed very weak white fluorescence.

A gemological microscope can often reveal a well-preserved wood grain structure in petrified wood samples. Studies of wood structure generally involve the transverse, tangential, and radial sections of the trunk (R.F. Evert, Esau’s Plant Anatomy: Meristems, Cells, and Tissues of the Plant Body: Their Structure, Function, and Development, 3rd ed., John Wiley & Sons, Hoboken, New Jersey, 2006, pp. 203, 292–296). A transverse section of one of the samples (figure 3) showed several tiny oval-shaped pores filled with quartz or opal (e.g., S. Saminpanya and F.L. Sutherland, “Silica phase-transformations during diagenesis within petrified woods found in fluvial deposits from Thailand-Myanmar,” Sedimentary Geology, Vol. 290, 2013, pp. 15–26). The samples also showed thin parallel rays, groups of cells oriented perpendicular to the trunk’s main axis. In some samples, the parenchyma (the most common plant tissue cells) consisted of pale lines or bands running across the rays. Others showed parenchyma surrounding a pore on the long and parallel wood grains of the tangential section, or dark-colored pores extending the length of the trunk. On the radial section, the pores ran the length of the trunk, with wood grains perpendicular to the pores.

Figure 3. Oval pores and rays (wavy white lines) are seen on a transverse section of this
petrified wood sample, and the growth rings are visible as two lines crossing the image.
Photomicrograph by Seriwat Saminpanya; field of view 10 mm.
Raman spectra were characteristic of opal (according to the RRUFF database, rruff.info), quartz, and moganite (K.J. Kingma and R.J. Hemley, “Raman spectroscopic study of microcrystalline silica,” American Mineralogist, Vol. 79, 1994, pp. 269–273). Figure 4 shows the peaks for the TAK, BHK, and CYP samples; peaks for KDH (which included opal) and MYR samples were previously presented (Saminpanya and Sutherland, 2013). Most of the quartz material displayed peaks at 354, 395–397, and 464–466 cm–1, with different colors within a sample exhibiting different peak intensities. Some samples showed only major peaks of quartz at 464–466 cm–1. Moganite was mixed with quartz in one sample apiece from CYP, KDH, and MYR, indicated by peaks at 503–506 cm–1, close to the reference peak of 501 cm–1 (Kingma and Hemley, 1994). Two KDH samples showed bands centered at 1587 and 1607 cm–1, characteristic of opal (Saminpanya and Sutherland, 2013), which was probably responsible for the weak to moderate chalky white fluorescence in some of the samples.

Figure 4. Raman spectra of petrified wood samples from Chyaphum (CYP), Tak (TAK),
and Khon Kaen (BHK) with quartz (Q) peaks at 465 cm–1. Samples from Chyaphum
show a moganite (M) peak at 503–506 cm–1.
XRD showed that the quartz peaks had an average 2Θ of 21.0, 26.7, 36.6, 39.6, 40.4, 42.5, 45.9, 50.2, and 55.0 degrees; the opal-CT peaks had an average 2Θ of 20.7, 21.7, 36.0, 44.0, and 56.9 degrees (again, see rruff.info). Quartz appeared in the XRD peaks of samples from all localities, but the opal-CT was found only in samples from KDH and MYR. The diffractogram of opal-CT in one sample from KDH appeared noisy. This may be due to its amorphous nature, though extending the XRD scan times may improve the resolution of the peaks. At this stage, XRD can only detect quartz and opal from these samples. @chapter:37


Publication Year: 2019 Title: Plume Agate from Iran Abstract: Figure 1. Iranian plume agate (22.45–82.03 ct) from the Ferdows agate field comes in two main varieties. The material on the left with white, green, and orange inclusions is known as “spring agate.” The stones on the right with red, yellow, and green inclusions are called “autumn agate.” Photo by Diego Sanchez.
Iran has long had a reputation as a source of quality agate, principally derived from extensive volcanic deposits throughout the country. Archaeological research on ancient tombs and finds in early human settlement sites there show that agate, chalcedony, and jasper were used not only for arrowheads and other stony instruments but also for ornamental beads and pendants.

Figure 2. Iranian “spring agate” showcases inclusions that are typically green, white, and orange. Photomicrograph by Nathan Renfro; field of view 3.78 mm.

Figure 3. A display of orangy red, green, and yellow inclusions seen in “autumn agate” from Iran. Photomicrograph by Nathan Renfro; field of view 6.00 mm.
Today, Iranian agates are primarily traded in the city of Mashhad, the largest holy city of Iran and the capital of the northwest province of Khorasan. Several varieties can be found in the market, but plume agates are the most colorful and most sought after. The samples of Iranian agate examined by the authors contained numerous plume structures in a variety of colors including green, yellow, red, white, and orange (figure 1). These plume structures are characterized by elongate billowy inclusions that can resemble clouds of smoke or feathers. The material with predominantly green, white, and orange inclusions is sold as “Bahary” (spring) agate (figure 2). The material that is principally green, yellow, and red is sold as “Paaeasy” (autumn) agate (figure 3).

Figure 4. An agate sample collected at the Aysak area in the Ferdows agate field in the southern region of Iran’s Khorasan Province. Photo by Hamid Mir-Blukey.
The samples examined were acquired in Iran by author MMS from Dr. Hamid Mir-Blukey, who has a private mining claim in the Ferdows agate field in the southern region of Khorasan (figure 4). Mining there is done mainly with primitive hand tools at or near the surface, where veins of agate are exposed as they weather out of their volcanic host rock.
While most material from this region is locally traded, the area could become an important global source for plume agate. @chapter:3


Publication Year: - Title: Describing 58-facet Round Brilliant-Cut Diamonds at GIA Abstract: Today’s round brilliant-cut diamonds showcase the gem’s sparkling optics. They are the most recent expression of a cutting style that has been around for centuries. Photo by Eric Welch, © GIA, courtesy of Signed Pieces, New York

Introduction
Most consumers in today’s marketplace choose round brilliant-cut diamonds fashioned to meet modern concepts of beauty. These sparkling gems represent the collective talents of generations of skilled cutters over more than six centuries.

As diamond cuts evolved into today’s 57- or 58-facet round brilliants, styles progressed through many stages. By 1750, when the brilliant cut had developed into a style with a circular face-up outline, it had passed through many variations in facet size and proportions. These included table size, crown height, length of the lower half facets, total depth, and culet size.

This illustration shows the names and arrangement of the facets of a standard round
brilliant-cut. Illustration by Peter Johnston, © GIA
This progression has resulted in diamonds from different periods having quite distinct appearances. Over time, table facets have become larger, culets smaller, and star facets and lower half facets longer. If you rock or tilt one of the older-style gems, you’ll see a different face-up pattern of light and dark than you would with a contemporary brilliant-cut.

	Transition to Modern Brilliants

This video shows three styles of brilliants with round face-up outlines. From left to right, they are an old European cut, in place by 1750; a “transitional” brilliant from around 1880; and a modern round brilliant, in place since the 1950s. The transitional cut is labeled “circular brilliant” in the video; this is the same term now used by GIA on grading reports.The three animations show how cutting styles developed over time, causing the different face-up patterns associated with each proportion set. Animations by Al Gilbertson, © GIA
Many beautiful older diamonds present a conundrum for diamond-grading laboratories—including GIA's—because their proportions diverge from contemporary conventions. This makes it difficult to judge them against today’s aesthetic. In spite of this, there is a market for their antique beauty. In fact, some consumers cherish their different interplay with light.

Compared to a modern round brilliant cut, this older-style 1.07-ct. brilliant has a much smaller table (38.5 percent), a higher crown, shorter lower halves, and a much larger culet. Digitally modified image by Al Gilbertson, © GIA, courtesy of Michael Goldstein
Compared to a modern brilliant, older gems typically show larger face-up patterns of light and dark—what might be described as a “checkerboard” or “blocky” pattern. A modern brilliant can display a tighter mosaic of light and dark that might be described as “splintery” by those who prefer older cutting styles.

Many older round brilliants were cut between the 1870s and the 1940s. Because some served as transitions between older and more-modern styles, some trade professionals call them “transitional cuts.”

Recent high prices for precious metals have caused many pieces containing older-style diamonds to be broken up, releasing more of these beautiful gems into the market and increasing appreciation for their historic nature.

This article explains GIA’s approach to describing these beautiful older-style brilliant-cut diamonds.
The GIA Cut-Grading System for Unmodified Brilliant-Cut Diamonds
In 2005, GIA introduced a cut-grading system for unmodified round brilliant cut diamonds. The name “unmodified round brilliant” was applied to a symmetrical round cut with a regular array of 58 facets, cut to modern standards. The system was the culmination of years of research that included the results of preference testing among a wide variety of groups, including trade professionals and consumers.

GIA designed the system to assess the design quality and craftsmanship of diamonds cut in the standard round brilliant style when compared to modern preferences. The system’s grades are based on modern-day conventions and assess the proportions that yield the best combination of brightness, fire, scintillation, and pattern. There are five grades: Excellent, Very Good, Good, Fair, and Poor.

GIA’s cut scale for unmodified round brilliant-cut diamonds includes five grades. Today, the majority of the round brilliant cuts graded by GIA fit into the top two grades. This illustration shows some of the key proportion parameters that impact a round brilliant-cut diamond’s appearance. Illustration by Peter Johnston, © GIA

GIA’s cut-grading system was designed to assess the beauty and craftsmanship of modern round brilliant-cut diamonds like this 2.78-ct. gem. Photo by Robert Weldon, © GIA

This illustration shows the facet arrangement of a modern round brilliant. © GIA
The Old European Cut
Historically, GIA has described unmodified round brilliant-cut diamonds as either “round brilliant” or “old European.”

The old European cut was an early evolutionary stage in the progression toward the modern round brilliant. In general, trade professionals characterize old European cuts as having small table facets, heavy crowns, and overall “deep” or “steep” proportions.

This diamond has a small table, large culet, and short lower-half facets. These are typical of diamonds from the late 1800s. This style kept evolving until the 1950s, when it would have a larger table, longer lower-half facets, and a smaller culet. Photo by Al Gilbertson, © GIA

This illustration shows the facet arrangement of an old European brilliant cut. © GIA
Initially, GIA allowed only one exception—the old European cut—into its cut-grading system. This accommodated the distinctive proportions of diamonds cut in this classic style. Its appearance is associated with a time that predates expectations of conformity with the appearance of the modern-day round brilliant. As a result, GIA does not apply a cut grade to diamonds cut in the old European style.

GIA identifies classic old European cuts using these criteria:

 Table size: less than or equal to 53 percent
 Crown angle: greater than or equal to 40 degrees
 Lower half facet length: less than or equal to 60 percent
 Culet size: slightly large or larger

These parameters are derived from historical definitions of the old European cutting style, staff observations, and discussions with trade professionals. They ensure that these diamonds are not judged by standards that they were never fashioned to meet, and from which they would likely receive a “Fair” or “Poor” cut grade. Dealers marketing the unique appearance of these diamonds have long contended that their stones are unduly penalized by the application of modern cut-grade criteria.

In practice, if a diamond meets three out of the four criteria, it will still receive the old European cut designation on a GIA grading report. The report simply provides the gem’s measurements and grades for color and clarity. This is because GIA recognizes that, centuries ago, cutters working with natural material tried to retain as much of the original weight of the crystal as possible, so proportions often differed wildly.
Styles between Old European and Modern Round Brilliant Cuts
The old European cut was by no means the last step in the journey toward fully modern round brilliants. As cutters continued to experiment with proportions, there were many incremental steps between the old European style and the modern round brilliant.

This Tiffany & Co. brooch contains seven diamonds with an approximate total weight of five carats. They are very well-matched, “transitional” round brilliants, with the smaller table facets (52 to 54 percent); short lower half facets; and culet sizes typical of cuts created during the period from 1870 to 1950. Photo by Robert Weldon, © GIA
With growing interest in the allure of these historic cutting styles, GIA receives many diamonds in styles close to—but not quite meeting—old European criteria. Expectations for them are quite different from contemporary expectations for a modern round brilliant. This drove GIA’s decision to add a new description to address diamonds that fall outside the existing categories of both old European and modern round brilliant.
The Circular Brilliant Designation
GIA sought to address older-style diamonds that aren’t strictly Old European, but also aren’t cut to meet modern standards. Previously, GIA graders had to decide whether to call a stone a round brilliant and grade it according to contemporary standards, or to call it an old European cut and simply record color and clarity without a cut grade.

To establish judgment criteria and help define these diamonds, GIA met with members of the trade and borrowed many examples of transitional cuts from dealers. The goals were to:

 Create a new description for older-style rounds that reflects their historic cutting approach
 Prevent cut grades from being assigned to diamonds that were never fashioned to modern round-brilliant parameters
 Prevent poorly cut modern round brilliants from passing through the GIA cut-grading system without receiving grades

The GIA study uncovered a number of stones that were not classic old European cuts, but that weren’t modern round brilliants, either. They also looked neither like well cut nor poorly cut modern round brilliants.

In general, the diamonds resembled the old European cut style, but they didn’t meet GIA’s required proportion parameters for that description. Although culets were often slightly large or larger, a number of examples had medium culets. Table facet sizes ranged from 43 to 62 percent, which made this parameter difficult to use as a standard for a new category. The two characteristics that most of the stones shared were shorter lower half and shorter star facets.

Following this review, GIA decided to introduce a new description for 58-facet round brilliants. The requirements for a stone to fall into this new category are:

 Lower half length: less than or equal to 65 percent
 Star length: less than or equal to 50 percent
 Culet size: medium or larger

The new description used on GIA reports for these diamonds is “circular brilliant.” All three criteria must apply for the diamond to be designated as a circular brilliant on the GIA grading report. This designation acknowledges that the diamond is not a modern-day round brilliant, suggests a description for rounds of earlier times, and keeps the historic old European cut definition unaltered.

This illustration shows the facet arrangement of a circular brilliant. © GIA
Prior to the new circular brilliant designation, GIA graded any diamond outside these parameters as though it was a modern brilliant. As with the old European cut, reports for diamonds that fall into this new category aren’t assigned a cut grade.

These diamonds evoke a bygone romantic era. Their shorter lower halves contribute to a different pattern of light and dark than that seen in an equivalent-size modern round brilliant cut, and that some consumers cherish. By establishing the circular brilliant term and the parameters that help define it, GIA has recognized the unique nature of these antique diamonds. @chapter:31


Publication Year: 2015 Title: Assembled Cultured Blister Pearl with an Unusual Component Abstract: Figure 1. This blue-violet assembled cultured blister pearl (mabe) weighed 2.44 carats and measured 10.23 × 5.86 mm. Photo by Lhapsin Nillapat.

	GIA’s Bangkok laboratory recently examined a blue-violet assembled cultured blister pearl (mabe) weighing 2.44 ct and measuring 10.23 × 5.86 mm (figure 1). The specimen had the appearance of a typical mabe pearl, exhibiting a boundary line between the nacre face and shell base. 2D microradiography showed a component with an unusual fluted shape, with radio-translucency similar to that of the CaCO3 nacre and the shell (figure 2).

Figure 2. A microradiograph of the intact assembled cultured blister pearl prior to sawing revealed an internal component. The radio-translucency of the object, the nacre, and the shell base are similar. Image by Areeya Manustrong.

	GIA has examined the characteristics of mabe pearls used in commercial jewelry over the years (see Lab Notes: Summer 1981, pp. 104–105; Summer 1991, pp. 111–112; Fall 1991, p. 177; Summer 1992, pp. 126–127; Fall 1992, pp. 195–196; Fall 1996, p. 210), but none of these notes mentioned this unusual component. In Bangkok, this feature has been seen five times in mabe pearls submitted for testing since 2010; questions about its identity and purpose have been raised since the first observation.

	Out of curiosity, one client decided to cut their sample in half in order to examine the interior in more detail (figure 3, left). The two halves consisted of a thin nacre dome top, which was coated with a dark layer on the inner surface; an artificial resinous material; and the white fluted object bordering the shell base. The fluted object was translucent, and a clear spiderweb structure was visible at 10× magnification. When exposed to standard short-wave UV radiation (254 nm) and examined in the DiamondView, this object showed a moderate white blue reaction that followed the spiderweb pattern (figure 3, right).

Figure 3. Left: The cross-section revealed the white fluted object with a spiderweb structure bordering the shell base. Photo by Sasithorn Engniwat. Right: DiamondView imaging showed a moderate white blue reaction following the spiderweb pattern. DiamondView image by Artitaya Homkrajae.

	Further investigation with Raman spectroscopy using a 488 nm laser revealed a calcite spectrum with peaks at 159, 285, 716, 1088, and 1750 cm–1, similar to white coral (Corallium secundum). A small peak related to carotenoid pigments was present at 1020 cm–1 (e.g., J. Urmos et al., “Characterization of some biogenic carbonates with Raman spectroscopy,” American Mineralogist, Vol. 76, 1991, pp. 641–646).

	Based on the spiderweb structure, radio-translucency, calcite spectrum, and general appearance, the object appeared to be a biogenic carbonate. White coral was the first material considered. Further research revealed accounts of sea urchin sections used in some assembled cultured blister pearls from Bali, Indonesia, in “Kuta” pearls (E. Strack, Pearls, Ruhle-Diebener-Verlag, Stuttgart, Germany, 2006, p. 605). Regardless of identity, the reason for including this material within some mabe pearls remains uncertain. It does not appear related to either the formation of the mabe pearl component or its weight and stability. @chapter:14


Publication Year: - Title: Spring 2011 Gem News International Abstract: 2011 Tucson
Colored Stones and Organic Materials
	            Faceted Cavansite
	            New Find of Green Grossular at Merelani, Tanzania
	            Blue Quartz Colored by Trolleite and Lazulite Inclusions
	            Spectral Interference in Quartz from India
	            Scapolite from India
	            Spinel from Northern Vietnam, Including a New Mine at Lang Chap
	            Gem Zektzerite
Synthetics and Simulants
	            “Coral Sea” Agate
	            Dendritic Agate in Doublets, Inlays, and Jewelry
GNI Regular Features
Diamonds
	            Artisanal Diamond Mining in Liberia
Colored Stones and Organic Materials
	            Update on Emerald Mining at Kagem, Zambia
	            Pargasite from Tanzania
	            Scapolite from Afghanistan
	            Tourmaline Finds at Mt. Marie, Paris, Maine
	            The Origin of Color in Tourmaline from Mt. Marie, Maine
Synthetics and Simulants
	            Trapiche Emerald Imitation
	            A New Rough Nephrite Imitation
	            A Skillfully Crafted Non-Nacreous Pearl Imitation
	            Plastic-Coated Quartz, Imitating Emerald
Treatments
	            Lead Glass-Filled Trapiche Ruby
Miscellaneous
	            Myanmar Gem Emporium
In Memoriam
	            Kurt Nassau (1927-2010), scientist, contributor, and review board member for G&G

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	DATA DEPOSITORY

Electron Microprobe Analyses of Inclusions
	May 2, 2011 @chapter:0


Publication Year: 2018 Title: GSA 2018 Report Abstract: Figure 1. Each year, the GIA booth at the GSA exhibition hall attracts participants from all over the world. Here, Paula Rucinski (left) and Dona Dirlam (right) speak with a visitor to the booth. Photo by Cathy Jonathan.

The Geological Society of America (GSA) annual meeting took place in Indianapolis November 4–7. GIA participated as both exhibitor and technical session holder. In total, 21 presenters reported new findings on a broad range of research topics. The GIA booth and the two technical sessions attracted a large audience with an interest in gemology (figure 1).

Figure 2. Richard Berg from the Montana Bureau of Mines and Geology presented his poster on Montana sapphires at the GSA annual meeting. Photo by Tao Hsu.
The “Gemological Research in the 21st Century” technical program included both poster and speaker sessions. Seven posters were presented on the second day of the conference (figure 2). Kyle Tollefson (Louisiana State University) and Phillip Ihinger (University of Wisconsin-Eau Claire) reported their characterization study on watermelon tourmaline. Their spectroscopic measurements showed that the chromophores Fe and Mn correlate to green and pink colorations, as expected. The infrared spectroscopy and microprobe analyses showed similar trends of hydroxyl occupancy on the V site in this type of tourmaline. Nikita Kepezhinskas (University of Florida) presented the results of petrographic, geochemical, and isotopic analyses of moissanite and diamond from the shoshonite dike in eastern Finnmark, Norway. The shoshonite host of these minerals is a type of Mg- and K-rich basaltic rock, which is indicative of a subduction-modified mantle source. This study proved that carbonate recycling into the lower mantle through subduction, followed by the formation of superdeep diamonds, moissanite, and other carbides, plays an important role in the global carbon cycle. Paul Johnson and Kyaw Soe Moe (GIA, New York) showed an unusual find of a natural diamond with a cuboctahedral growth habit. This diamond should alert gem labs to the fact that cuboctahedral growth does not occur just in HPHT synthetic diamonds. This special diamond also indicated a potentially very interesting and uncommon growth history before it was lifted to the surface of the earth. Richard Berg (Montana Bureau of Mines and Geology) described significant magmatic splitting of sapphire xenocrysts in basaltic trachyandesite sill. Through extremely careful examination of in situ sapphires in their host rock and advanced instrument analyses such as SEM, XRD, and EDS, he was able to assemble a sequence of what happened to the sapphires before emplacement into their current location. Ying Song (China University of Petroleum) introduced a newly designed and developed computer-vision based intelligent RI measuring system. This system aimed to enhance the clarity and efficiency of RI and other optical measurements. Classroom demonstration, rapid crystal identification, optic axis characterization, and crystal orientation determination are the four modes currently implemented in this instrument. Ziyin Sun and coauthors (GIA, Carlsbad) displayed their study on chromophore strength in pyralspite garnet. Since multiple color-causing elements work singularly or together to color garnets, the authors isolated each of them and performed quantitative study by experimenting with various combinations of these chromophores’ UV-Vis-NIR spectra under different lighting conditions. Aaron Palke and coauthors (GIA, Carlsbad) reported on a Montana sapphire study aiming to unravel its gemological mysteries. Based on their inclusion and geochemical study, the authors proposed a new model of sapphire formation through peritectic melting reactions during partial melting of an Al-rich protolith.

Figure 3. Presenters, guests, and advocates from the GSA poster and speaker sessions. Left to right: Peter Heaney, Dona Dirlam, Mandy Krebs, Richard Berg, Mike Breeding, Jim Shigley, Tingting Gu, Tyler Sundell, Rachelle Turnier, Nancy McMillan, Evan Smith, Chunhui Zhou, Barbara Dutrow, and Sally Eaton-Magaña. Photo by Tao Hsu.
This year’s speaker session attracted 14 presenters from multiple research institutes and universities (figure 3). Mike Breeding (GIA, Carlsbad) kicked off the session with an overview of colored diamonds formed at different depths within the earth. He elaborated on the defects that cause diamond’s blue, pink, yellow, brown, and green colors. The audience was given a grand tour of colored diamond formation, from the transition zone all the way to the surface of the earth. Next, Sally Eaton-Magaña (GIA, Carlsbad) presented her photoluminescence study on pink diamonds based on GIA’s uniquely large database. She explained the cause of pink color as a 550 nm absorption band and explored the difference of pink coloration in various diamond types. She also showed some visual clues that can help to separate pink diamonds from different sources. Tyler Sundell (Missouri State University) talked about the feasibility of using time-of-flight secondary ion mass spectrometry (ToF-SIMS) to image diamonds, especially on their trace-element composition and isotope analyses. Evaluation of this method focuses on its spatial resolution and analytical precision. Results show that this method lacks the precision to quantify carbon isotope values. Karen Smit (GIA, New York) presented her research on natural black diamonds found in the billion-year-old Marange conglomerate (Zimbabwe). Diamonds from this source are full of fractures and can be easily treated to achieve a more valuable fancy black color grade, which makes identification challenging without characterization of the natural stones. Visual observation of graphite grain size and the detection of methane associated with the micro-inclusions are necessary to distinguish between natural and treated Marange diamonds. Evan Smith (GIA, New York) delivered his research on carbonatitic melt inclusions he discovered in partially healed cracks within a CLIPPIR diamond (for more on these diamonds, see Winter 2017 G&G, pp. 388–403). The characterization of these inclusions is consistent with carbonatitic melt, providing direct evidence of this melt’s existence at mantle depths. Russell Harmon (North Carolina State University) evaluated the potential of handheld laser-induced breakdown spectroscopy (LIBS) to identify garnets associated with kimberlites, the host rock of most diamond deposits. This study aims to test whether this instrument will help diamond exploration in the field. Initial results showed that it works very well on garnets from the South Africa kimberlite field but not as well on some other samples, especially those from extensive solid solution. Rod Smith (Geological Survey of Canada) presented field and lab research on the Banks Island region in the western Canadian Arctic, aiming to find promising diamond-bearing kimberlite. Based on newly found stream sediments and till samples, geothermometry data, and Lu-Hf geochronology results, the research group demonstrated the need to continue the search for potential diamond-bearing kimberlite in this region and presented a potentially unknown kimberlite glacial dispersal model. Tingting Gu (GIA, New York) talked about inclusion studies on type IaB diamonds. This study offered the first piece of evidence that hydrous phosphate can subduct to the depth of the transition zone. It also showed the first ringwoodite found in diamond, which proved that this diamond formed in the deep mantle.
The second half of the speaker session started with Mandy Krebs (GIA, New York), who showed the application of Sr-Pb isotope data to colored gemstones’ country-of-origin determination. The analyses were done by thermal ionization mass spectrometry (TIMS) to precisely measure the Sr-Pb isotope compositions in gem corundum for the first time. The separation is promising for certain sources but less so for others. Rachelle Turnier (University of Wisconsin-Madison) used Raman spectroscopy to evaluate the depth of zircon inclusion formation. These zircons are inclusions in corundum sourced from different deposits. Her study is based on an ideal linear upshift of Raman band of zircon with increasing pressure. However, many other factors can influence this ideal situation, such as radiation damage, stress, and internal heterogeneity. With careful consideration of these influencing factors, using Raman as a zircon barometer can help to distinguish corundum from various sources. William Nachlas (Syracuse University) presented the three different formation mechanisms for rutilated quartz. These include the overgrowth/entrapment mechanism, the precipitation mechanism, and the grain boundary migration mechanism, each with different relative timing of quartz and rutile growth. All three mechanisms were reproduced with well-designed experiments. Peter Heaney (Penn State University) explored the reason behind the striking iridescence displayed by some ochre-colored botryoidal goethite. Dr. Heaney applied focused ion beam (FIB) milling and scanning electron microscopy (SEM) to zoom in on the internal structure of this gem. With these powerful tools, some subsurface void layers were revealed to be responsible for the angle-independent iridescence. The origin of these voids remains a mystery. Barbara Dutrow (Louisiana State University) reported a geochemistry study on some uncommon tourmaline + corundum–bearing rocks from Afghanistan’s Badakhshan Province with randomly oriented phlogopites as the matrix. Major, minor, and trace elements were measured with electron microprobe and laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS). The results indicate the involvement of boron-bearing fluids at the beginning of tourmaline growth and continuous infiltration of this fluid. The bulk composition of this rock is consistent with metasomatism of a clay-containing metacarbonate rock with a metamorphic overprint. Chunhui Zhou (GIA, New York) gave the first-ever pearl presentation in this technical session. Three American freshwater cultured pearls were sliced open and their oxygen isotopes were analyzed using SIMS, aiming to reconstruct the ambient water temperature when the nacre formed. This method is very useful in terms of growth cycle determination and can potentially shine a light on pearl origin determination. @chapter:0


Publication Year: 2018 Title: Quarterly Crystal: Bubble in Fluorite Abstract: Figure 1. This 41.98 ct cluster of transparent green fluorite cubes contains a large primary two-phase fluid inclusion that was trapped between the cubes as they developed. Photo by Diego Sanchez.

The very lightly etched green fluorite crystals that come from the Rogerley mine, located in Rogerley Quarry, Weardale, County Durham, England, are well known for the beautiful bright fluorescence they display. Rogerley mine fluorite is highly fluorescent, turning bright bluish white on exposure to long-wave ultraviolet radiation.
The fluorescent fluorite from this locality will also take on a purplish color in sunlight. This effect, known as “daylight fluorescence,” appears to be unique to fluorite from the Weardale area. Research has shown that this intense fluorescence is due to an elevated rare-earth element (REE) content, including the elements cerium, lanthanum, neodymium, samarium, and yttrium.

Figure 2. In this registered pair of images, the movement of the gas phase in the fluorite cluster can be easily seen. Photomicrographs by Nathan Renfro; horizontal field of view 6.54 mm.
The Rogerley fluorite specimen shown in figure 1 measures 17.68 × 17.38 × 13.50 mm and weighs 41.98 ct. What makes this specimen the subject of this issue’s “Quarterly Crystal” is the presence of an eye-visible primary fluid inclusion with a moving gas phase. Along the interface, where the two growing crystals came together, negative space was created. This form of primary fluid inclusion hosts fluid remnants that were present when the fluorite was growing. When comparing the two photomicrographs in figure 2, the movement of the gas phase can be clearly seen. Fluid inclusions like this are not at all common in fluorite. @chapter:13


Publication Year: 2019 Title: Chatoyant Quartz/Tourmaline Doublet Abstract: Figure 1. This 4.86 ct cabochon displays unusual yellowish chatoyancy against a predominantly purple bodycolor. Photo by Shunsuke Nagai.

Doublets are assemblages of two different materials, often joined with cement. Historically they were composed of inexpensive materials used to imitate precious stones. Recently new combinations have been reported, such as a beryl/topaz doublet (Winter 2014 GNI, pp. 306–307), synthetic sapphire/synthetic spinel doublets (Winter 2016 Lab Notes, pp. 418–419), and a beryl/glass complex assemblage (Summer 2018 Lab Notes, pp. 206–208).
GIA’s Tokyo laboratory had the chance to examine a unique doublet. The 4.86 ct purplish cabochon, measuring 11.07 × 10.00 × 5.94 mm, appeared to display chatoyancy with a yellowish sheen (figure 1). The hydrostatic specific gravity (SG) and spot refractive index (RI) readings were 2.66 and 1.54, respectively. Assembled features with a cemented plane were easily recognized when viewed from the side, as shown in figure 2. Standard gemological testing, microscopic observation, and infrared spectra revealed that the cabochon segment was a natural amethyst. There were no parallel inclusions that might have caused chatoyancy in this segment. On the other hand, the semitransparent yellowish base had parallel striations and tube-like inclusions throughout (figure 3). Raman spectroscopy identified the base as tourmaline.

Figure 2. Viewed from the side, the assemblage was obvious. Trapped bubbles in the cemented plane can also be seen. Photo by Shunsuke Nagai.

Figure 3. Cavities on the base show the parallel striations and columnar or tube-like inclusions. Photomicrograph by Yusuke Katsurada; field of view 1.88 mm.
Parallel inclusions located near the bottom of a cabochon can create a chatoyant phenomenon (Winter 2017 Lab Notes, pp. 459–460). This assembled item displayed a similar effect due to the flat tourmaline base with parallel structures. When light was reflected through the amethyst by the tourmaline base, the parallel striations and tube-like inclusions in the tourmaline created the band of reflected light that appeared on the cabochon. Transparent amethyst and semitransparent yellow tourmaline are an uncommon combination. This doublet is an example that assemblages are not always aimed to imitate precious stones but can be creative artworks. @chapter:19


Publication Year: 2021 Title: Flux-Induced Fingerprints in Flame-Fusion Synthetic Sapphire Abstract: Figure 1. Face-up view of the 2.81 ct flame-fusion synthetic sapphire with flux fingerprints. Photo by Diego Sanchez.

The Carlsbad laboratory recently received a blue cushion mixed cut measuring 9.07 × 7.07 × 4.62 mm (figure 1). Standard gemological testing gave a refractive index of 1.760–1.768, consistent with sapphire. Microscopic examination uncovered a fingerprint resembling those found in natural sapphires (figure 2). Closer examination revealed the fingerprint to be a flux fingerprint. When the stone was immersed in mineral oil, curved color banding diagnostic of flame-fusion lab-grown sapphire became visible (figure 3).

Figure 2. This flux fingerprint in the lab-grown sapphire is similar to the fingerprints found in natural sapphire. Photomicrograph by Nathan Renfro and Michaela Stephan; field of view 1.76 mm.

Figure 3. When immersed in mineral oil, curved color banding is visible along with a natural-looking flux fingerprint and large gas bubbles. Photomicrograph by Nathan Renfro and Michaela Stephan; field of view 7.19 mm.
Typically, a flame-fusion-grown ruby or sapphire with healed fractures has undergone a process known as “quench crackling,” where fractures are created in the stone by heating and subsequent rapid cooling. This stone did not show the characteristic cellular fracturing created by this process, making the healed fractures appear even more natural. The randomly fractured stone had been immersed in a flux melt. The flux melt filled and partially healed the fractures while the stone gradually cooled, which resulted in natural-looking fingerprints of residual flux. This treatment is usually seen in flame-fusion synthetic rubies (K. Schmetzer and F.-J Schupp, “Flux-induced fingerprint patterns in synthetic ruby: An update,” Spring 1994 G&G, pp. 33–38). @chapter:12


Publication Year: - Title: Get Started on 2017 Continuing Education Recognition Program Abstract: The first three assignments from the 2017 Continuing Education Recognition Program cover American freshwater pearls, diamond jewelry manufacturing in India and how to get the most from diamond rough.

Natural American Freshwater Pearls. Diamond Jewelry Manufacturing in India. Diamond Cutting in India.

These are just some of the gem and jewelry topics you will learn more about as you complete this year’s Continuing Education Recognition Education Program. Created for GIA graduates who hold a Graduate Gemologist or Gemologist diploma, the continuing education program includes a variety of engaging slideshows and animation, interactive self-testing, instructional videos and expert interviews, featuring the most up-to-date discoveries and research from GIA field gemologists who have traveled to the source. The program is designed to help graduates stay up to date with the latest gem and jewelry news and information.

You will have continuous access to the entire course – including the assignments, GIA eLearning courses and previous years' continuing education assignments and the multimedia archive – until the end of the calendar year. Each graduate who completes the Continuing Education Recognition Program will receive a certificate that displays their expertise and commitment to staying on top of gemological developments.

“The word is out amongst our graduates and corporate education clientele about the value and importance of this program,” says Kate Donovan, alumni relations manager. “Relevance is key in a competitive market, and this program gives GIA graduates the opportunity to keep up the standard of education they worked so hard to achieve. Having access to the entire gemological course data that new GIA students are currently using is invaluable.”

Be sure to complete all eight assignments by Dec. 31 to receive your Continuing Education Recognition Program certificate.

Here’s a brief overview of the 2017 assignments to date:
Assignment 1: Natural American Freshwater Pearls
From the unassuming rivers and lakes of America come the most sublime treasures: natural American freshwater pearls. They have been prized for centuries as evidenced by the numerous pearls found in Native American burial mounds. At one time, these treasures were more readily available, a byproduct of a once-thriving shell harvesting industry. Today there is less demand for mussel shells and many fewer shell divers. The result is that the recovery of natural pearls has become much more uncommon. In this interview, Gina Latendresse, president of the American Pearl Company, shares some unique and rare natural American freshwater pearls.
Assignment 2: Diamond Jewelry Manufacturing in India
The creation and use of jewelry for adornment has a tradition dating back thousands of years in India. Additionally, Indian jewelry is used to signify status and is often seen as a source of financial security. Indian jewelers have proudly upheld and continue to pass down traditional jewelry making methods, but they have also evolved and today, take advantage of a wide range of modern jewelry manufacturing technologies. A team from GIA visited a number of modern jewelry manufacturing companies in India in 2016. This video highlights some of what they witnessed.
Assignment 3: Getting the Most from Diamond Rough
India’s love affair with diamonds goes back thousands of years. Historians believe India was trading diamonds as early as the fourth century BCE. Culled from its streams and rivers, diamonds found their way into the hands of Indian royalty and gem lovers throughout the Western world. It is fitting that some of today’s most advanced technology is being utilized in the diamond manufacturing companies of India. Advances in diamond scanning and planning have resulted in a marked increase in yield from rough. This assignment tours several diamond cutting factories to observe some of this technology in action.

Don’t miss this chance to learn more valuable and exciting information from GIA’s top experts. Find out more about GIA’s Continuing Education Recognition Program. You can also contact the GIA Alumni Association at +1 760 603 4145 or email alumni@gia.edu. @chapter:24


Publication Year: 2014 Title: Dyed Bone as a Red Coral Imitation Abstract: Figure 1. This 8.86 ct orange-red cabochon, submitted as coral, was identified as dyed bone. Photo by Gagan Choudhary.

Numerous materials have been widely used to imitate red coral: glass, plastic, ceramics, composites, and dyed shells. Recently, the Gem Testing Laboratory in Jaipur examined an 8.86 ct orange-red cabochon measuring 16.56 × 12.19 × 7.34 mm (figure 1) that was presented as red coral but proved to be dyed bone, an unusual imitation.
Initial observation showed a strong resemblance to red coral, but careful microscopic observation proved otherwise. The sample lacked the typical “tree ring” or striated growth structure seen in corals, though it did display a network of fine veins throughout. Viewed from above, these veins appeared subparallel and were oriented along the length of the cabochon (figure 2). The veins also displayed orange-red color concentrations against the cabochon’s whitish bodycolor (again, see figure 2), suggesting that the material was both dyed and organic.

Figure 2.  The dyed bone displayed subparallel veins oriented along the length of the cabochon; also note the orange-red color concentrations against the sample’s whitish bodycolor. Photomicrograph by Gagan Choudhary; magnified 48×.
Detailed observations of the sample from all sides revealed that the subparallel veins were confined to circular concentric planes oriented along the length of the cabochon (figure 3, top); the individual veins were further surrounded by concentric whitish rings (figure 3, bottom). These structural features ruled out the possibility of coral, but the identity had yet to be established.

Figure 3. Subparallel veins were confined to circular concentric planes oriented along
the length of the cabochon (top), while the individual veins were surrounded by concentric whitish rings (bottom). Photomicrographs by Gagan Choudhary; magnified 40× (top) and 56× (bottom).
The sample’s spot RI was approximately 1.56, without any noticeable birefringence blink, while its hydrostatic SG was 2.01. Under a UV lamp, it displayed pinkish orange patchy fluorescence (which was stronger under long-wave UV). This characteristic is typically associated with dyes. Qualitative EDXRF analysis revealed the presence of phosphorus and calcium. Chemical, gemological, and observational features indicated bone, which was further confirmed by Raman spectroscopy. Raman spectra (figure 4) obtained using a 785 nm laser in the 200–2000 cm–1 region displayed a strong peak at approximately 960 cm–1, with weaker peaks at approximately 430, 586, and 1072 cm–1. Also present were a few indistinct features in the 1200–1700 cm–1 region. The peaks at approximately 960, 586, and 430 cm–1 were attributed to PO3–4 bending and stretching, and the one at 1072 cm–1 to CO3–4 stretching. The indistinct features between 1200 and 1700 cm–1 were due to collagen—the essential component of bone tissue (C. Kontoyannis et al., “Analysis of bone composition with Raman spectroscopy,” Proceedings of the 13th Panhellenic Pharmaceutical Congress, 2012, http://nemertes.lis.upatras.gr/jspui/bitstream/10889/5187/1/PMO031.pdf).

Figure 23. The bone’s Raman spectrum showed major PO3–4 peaks at about 960, 586, and 430 cm–1; a CO3–4 peak at 1072 cm–1; and collagen-related peaks in the 1200–1700 cm–1 region.
Bones have been used as jewelry since ancient times, and some specimens are dyed or stained to make them appear older (Summer 2006 Lab Notes, p. 160). Bone is used to imitate ivory, but this is the first time we have seen a bone dyed red and presented as coral, an interesting and unusual imitation. Although the market penetration of this material is unknown, we cannot rule out the possibility of it being mixed in packets of red coral, and this separation would pose a challenge for jewelers and gemologists. @chapter:40


Publication Year: 2024 Title: Morganite from Blue Star Gems Abstract: Figure 1. The 236.27 ct pear-shaped untreated morganite from old Madagascar stock was designed by Prakash Chand Vijay, who also oversaw the cutting. Photos by Jennifer Stone-Sundberg (left) and Robert Weldon (right). Courtesy of Blue Star Gems.
Morganite, a pink gem discovered in 1910 in Madagascar, was identified as a new variety of beryl by George Kunz, who named it in honor of his friend J.P. Morgan. Morganite has since been found in several other countries, most notably Brazil, Mozambique, Afghanistan, China, Russia, and the United States. The most productive mine today is in Minas Gerais, Brazil.
At the GJX show, an extraordinary morganite stood out at the Blue Star Gems (New York City) booth (figure 1). Owner Prakash Chand Vijay indicated that the 236.27 ct stone was from vintage stock from the original morganite mine in Madagascar. This one-of-a-kind untreated stone had a particularly pleasing deep warm pink color and a striking constellation of small inclusions scattered throughout. With Vijay’s expertise in the selection and cutting of stones from Africa, he participated in and oversaw the cutting of this exceptional gem.

Figure 2. Left: Suite of morganite from Mozambique ranging from 27.90 ct (the center rectangular step cut) to 92.34 ct (the largest pear). These stones underwent a lengthy heating and electron radiation treatment to bring out the best color and clarity. Right: Suite of aquamarines from Madagascar. Clockwise from left: 31.88 ct oval brilliant cut, 49.08 ct cushion cut, 35.80 ct rectangular step cut, and 24.51 ct pear brilliant cut. Photos by Prateek Vijay; courtesy of Blue Star Gems.
Vijay’s daughter, Jyoti Vijaywargi, said that this year they brought more than 100 pieces of attractively colored purplish pink morganite in sizes of over 20 carats each (figure 2, left). These stones came from Mozambique and underwent a lengthy heating and electron irradiation treatment in Germany to bring out the best color and clarity.
The enhancement of morganite color has been shifting from neutron irradiation to electron irradiation, avoiding the risk of a radioactive product (T. Stephan et al., “Irradiation treatment and gamma-ray spectroscopy of morganite,” 37th International Gemmological Conference Proceedings, Tokyo, 2023, pp. 123–125). Vijaywargi noted that due to the large sizes of their morganites, the entire process takes about five years to produce the quality seen, attesting to the value of the material and the patience of the vendor. The treatment itself takes about three and a half years, followed by an additional 18 months to let the stones cool down and be tested before they can be sold. Sometimes the stones do not respond to the treatment, and there is no color improvement at all. To date, there is no pretreatment testing to indicate whether the stones will respond to the treatment, so each run is a financial risk.
In addition to morganite, Blue Star Gems had extensive offerings of aquamarine (figure 2, right)—one of this year’s most popular stones—and tanzanite. The aquamarine comes from Madagascar. Despite global business challenges, the show proved successful for Blue Star Gems, particularly for high-end stones. The company was also able to attract new buyers this year.
Vijaywargi described the recent challenges around the pricing of wholesale versus retail items. On the wholesale side, prices for all goods have increased, yet these price changes have not been reflected at the retail end. As a vendor carrying substantial inventory of rare gemstones, Vijaywargi anticipates an increase in the value of Blue Star’s collection, which will require patience as a seller. @chapter:0


Publication Year: 2017 Title: Christmas Tree–Shaped Internal Feature In Diamond Abstract: Left: A 3.32 ct fancy-color diamond hosts a laser manufacturing remnant of unusual shape; here, it is seen with diffused fiber-optic illumination. Right: Rheinberg illumination accentuates the LMR’s resemblance to an evergreen tree. Photomicrographs by Jonathan Muyal; field of view 2.90 mm.
A 3.32 ct Fancy yellow marquise diamond recently submitted to GIA’s Carlsbad laboratory for color origin determination was of particular interest for its large, eye-visible laser manufacturing remnant (LMR). This LMR extended along a relatively straight path from a star facet through the pavilion and featured lily pad stress fractures stacked in parallel along its length, a composition reminiscent of a Christmas tree preserved within the diamond. With its resulting “green foliage” against a dark blue night, the use of Rheinberg color contrast illumination technique (N. Renfro,“Digital photomicrography for gemologists,” Summer 2015 G&G, pp. 144–159; Fall 2015 Micro-World, pp. 328–329) dramatically accentuated this already evocative scene (see above).

Unlike the remnants of laser drilling used to remove small inclusions, LMRs are an unintended consequence of either carelessness or unpredictable laser optics. As such, they are graded as clarity characteristics that can reduce the overall quality and value of a diamond. LMRs can occur during the laser cutting of a diamond. They appear in a variety of shapes but often resemble the remnants of internal laser drilling (Fall 2013 Lab Notes, p. 174).

Ironically, an accidental feature that might otherwise downgrade a diamond’s value can have a positive outcome. This unique and aesthetically pleasing internal feature has created an interesting collector’s gemstone, a perfect gift for the Christmas season! @chapter:31


Publication Year: - Title: Green Nephrite Jade Attracts Buyers in Tucson Abstract: Figure 1. For the first time in the history of the Olympics, the medals from the 2008 Beijing Games were mounted with gemstones. The nephrite jade bi, or flat rings, used in the medals were all from China’s Qinghai province. The gold medal was mounted with white nephrite, the color favored by the Chinese, while the silver and the bronze used greenish white and green nephrite, respectively. Courtesy of China Gems Magazine.

                      The Jade West Group, a leading nephrite jade company in North America for the past 30 years, drew many buyers at their 2015 GJX booth. Prized in Chinese culture for over 5,000 years, nephrite regained its momentum in the domestic Chinese market after the 2008 Beijing Olympics, when it was used in the gold, silver, and bronze medals (figure 1). The Chinese government launched a campaign promoting the significance of nephrite jade in the country’s history. This reignited the love of nephrite among the Chinese people, and the increasing demand and price drove a new surge of jade rush in northern British Columbia (BC).

A tectonic belt running from Alaska through British Columbia to Mexico favored the formation of nephrite. Tectonic and lithological contacts are the predominant ore body controls. BC has more than 50 known nephrite deposits, distributed mainly along tectonic inclusions of country rocks, dikes, and mafic rock layers within serpentinites, or along the contact between serpentinite and the wall rocks. This formation is very similar to other green nephrite occurrences all over the world. Nephrite is found both in situ and as boulders; the Polar Pride boulder, found in BC’s Polar mine, is a well-known example of the latter (figure 2).

Figure 2. Half of the Polar Pride jade boulder discovered in the Polar jade mine. The original boulder weighed 18 tons. Courtesy of Jade West Group.
Nephrite boulders are the products of erosion from the last ice age. They are usually drilled or sawed to test the quality, and only the good-quality material is transported for sale. While some of today’s nephrite is from boulders, primary deposits supply the bulk of BC’s production. This is partially due to the lack of high-quality boulders; however, the growing demand and price for nephrite also make it profitable to mine the primary deposits.

According to Kirk Makepeace, president of Jade West Group, the price of jewelry-grade jade from BC (figure 3) experienced at least a tenfold increase from a decade ago. Before 2008, top-quality nephrite from BC sold for about $20 a kilo; equivalent stones now range from $200 to $2,000 a kilo.

Figure 3. This strand of 41 nephrite beads is comprised of material from British Columbia’s Polar Mine. Photo by Robert Weldon; courtesy of Jade West Group.
The annual production of BC nephrite jade is about 400 tons. Most of the production comes from four active mines; together, they produce about three-quarters of the world’s high-quality green nephrite. Of these four, Jade West operates the Polar, Ogden, and Kutcho Jade mines. Jade West also deals with material from Wyoming and Siberia. Over the last 10 years, approximately 90% of the company’s BC production was exported to mainland China; the remaining 10% was sent to Taiwan, Vietnam, and Thailand.

	Figure 4. This Canadian Jade Fish Hook pendant features a piece of nephrite from the
	Kutcho Mine. This is one of the styles Jade West has customized for the North American
	market. Photo by Robert Weldon, courtesy of Jade West Group.
Jade West sends almost all of its rough nephrite to Guangdong for carving and jewelry manufacturing, with designs customized for different markets (figure 4). In addition to traditional carvings and jewelry, there is demand from Southeast Asian countries for giant Buddha statues and from Western countries for home decorations. This demand leads Mr. Makepeace to be very optimistic about the future availability of BC nephrite. @chapter:37