Publish Year: 2018 Title: Diamond Identification Abstract: Figure 1. A schematic of the model for each color state of a chameleon diamond based on absorption from valence band states to the proposed acceptor state being blocked by full compensation (the “yellow” state) or incomplete compensation when exposed to room lighting (the “green” state).
Complex Charge Transfer in Chameleon Diamonds: A Model of the Color-Change Process
James E. Butler1,2, Keal S. Byrne2, Wuyi Wang3, and Jeffrey E. Post2
1Cubic Carbon Ceramics, Washington, DC
2Department of Mineral Sciences, Smithsonian Institution, Washington, DC
3GIA, New York
A group of natural diamonds known as chameleon diamonds change color from green to yellow based on their exposure to light and heat. These diamonds also emit long-lived phosphorescence after UV excitation. We have observed the optical response of these diamonds to optical and thermal excitation and developed a model to explain the observed phenomena. A principal element of the model is the proposal of an acceptor state (figure 1), which should be observable in the near-infrared (NIR) region. Subsequently, we have observed the NIR absorption to this acceptor state, supporting our model of charge-transfer processes in these diamonds.
Melee Diamonds: Metal Defects and Treated Color
Shoko Odake
GIA, Tokyo
Gem-quality laboratory-grown diamonds are manufactured in large quantities. With frequent reports of the mixing of melee-sized synthetic diamonds with natural stones, demand for melee diamond screening is increasing. During melee diamond screening at GIA’s Tokyo lab, two notable types of samples with uncommon characteristics have been found.

Natural melee diamonds with silicon and nickel defects. Luminescence peaks derived from Si- and Ni-related defects are often observed in colorless melee grown by the HPHT method. The silicon-related defect, once considered proof of CVD-grown diamond, is now known to exist naturally as well (Breeding and Wang, 2008). Several colorless melee diamonds having both silicon- and nickel-related emissions have been found in GIA’s Tokyo lab; olivine inclusions were found in one of these samples. Spectroscopic and gemological features confirmed that the samples were grown in nature.
Irradiated laboratory-grown diamond melee found among irradiated natural melee diamonds. Several thousand greenish blue melee diamonds have been submitted by various clients to the Tokyo lab for testing. Each diamond’s color was attributed to a strong GR1 defect caused by irradiation treatment. Fourier-transform infrared (FTIR), photoluminescence (PL), and DiamondView analysis revealed that most of them were irradiated natural diamonds. Eight were irradiated CVD-grown diamonds, and one was an irradiated HPHT-grown specimen. The infrared spectrum of all the CVD samples showed a peak at 3123 cm–1, while their PL spectrum showed a doublet peak at 596/597 nm. Those peaks are specific to as-grown CVD diamonds, as annealing removes the peaks. From their spectra, these CVD specimens were considered irradiated without pre-annealing.

REFERENCE
Breeding C.M., Wang W. (2008) Occurrence of the Si-V defect center in natural colorless gem diamonds. Diamond and Related Materials, Vol. 17, pp. 1335–1344, http://dx.doi.org/10.1016/j.diamond.2008.01.075
Nitrogen in CVD-Grown Diamond
Alexander M. Zaitsev1,2, Kyaw Soe Moe2, and Wuyi Wang2
1College of Staten Island, City University of New York
2GIA, New York
In diamond grown by the CVD method, nitrogen behaves differently than it does in natural and HPHT-grown diamond. The most striking peculiarities are low efficiency of doping, formation of unique optical centers over a wide spectral range from the ultraviolet (UV) to the IR regions, and formation of unusual defects related to aggregated nitrogen. In order to gain a better insight into this problem, several nitrogen-doped specimens grown in GIA’s CVD diamond lab and a few commercial yellow CVD-grown diamonds have been studied in their as-grown (as-received) state and after electron irradiation and annealing at temperatures up to 1900°C (low-pressure, high-temperature treatment).
We found that the brightest pink color of electron-irradiated nitrogen-doped CVD-grown diamond is produced by the NV– center after annealing at temperatures of about 1000°C. Annealing at temperatures over 1600°C destroys the irradiation-induced pink color (figure 1).

Figure 1. The distribution of color in commercial nitrogen-doped CVD-grown diamond after electron irradiation and subsequent annealing at temperatures of 860°C (left) and 1900°C (right).
The most prominent optical centers in the IR spectral region (figure 2, left) produced absorptions at 2828, 2874, 2906, 2949, 3031, 3107, 3123, and 3310 cm–1 (latter two not shown). These are ascribed to nitrogen-hydrogen complexes. Two characteristic absorption features at 1293 and 1341 cm–1 (figure 2, right) are unique to CVD diamond. They are tentatively ascribed to a modified form of nitrogen A-aggregates.

Figure 2. These spectra show specific nitrogen-hydrogen absorption features in the two-phonon spectral range (left) and absorption of modified nitrogen A-aggregates (right) in nitrogen-doped CVD-grown diamond.
In the visible and NIR spectral ranges, characteristic nitrogen-related centers have zero-phonon lines (ZPLs) at 457, 462, 489, 498, 647, 722.5, 852.5, 865.5, 868.5, 908, 921.5, and 924.5 nm. The 489 nm feature is a major color center of electron-irradiated, nitrogen-doped CVD-grown diamond. This center, together with the GR1 center, is responsible for the green color in this material.
An assumption is made that N atoms may form clusters in highly nitrogen-doped CVD-grown diamonds. These clusters may result in broad-band luminescence at wavelengths of 360, 390, 535, and 720 nm and a strong broadening of the ZPLs of many optical centers.
Steps in Screening and ID of Laboratory-Grown Diamonds with Synthetic Diamond ID Kit
Branko Deljanin1 and John Chapman2
1CGL-GRS Swiss Canadian Gemlab, Vancouver, Canada
2Gemetrix, Perth, Western Australia
Laboratory-grown diamonds are created using either high-pressure, high-temperature (HPHT) or chemical vapor deposition (CVD). With the influx of manmade diamonds on the market over the past few years, instrument producers and labs have launched screening and detection instruments to help dealers and jewelers spot HPHT- or CVD-grown specimens.
Most standard instruments are inaccurate testers or just type I and type II screening devices that do not give a definite answer about diamond genesis. Over the last four annual Mediterranean Gemmological and Jewellery Conferences and more than 30 workshops given in 17 countries, we have assembled a portable new Synthetic Diamond Identification Kit. The kit comprises two portable instruments and two booklets:

A PL inspector (mini UV lamp with magnifier) to inspect laboratory-grown, treated, and natural diamonds using long- and short-wave fluorescence and phosphorescence
A 2017 handbook with images and explanation of long- and short-wave reactions of diamonds of all types
A mini foldable polariscope with portable light to separate natural diamonds using characteristic birefringence patterns from HPHT and CVD diamonds
A 2010 handbook with images and explanations of cross-polarized filter reactions of diamonds of all types

The combination of this kit with professional training could identify all HPHT-grown diamonds and most CVD-grown diamonds on the market, loose or mounted. Also available are melee and jewelry inspectors consisting of larger UV lamps with magnifiers designed for identification of small loose or mounted diamonds.
Different diamond types and subtypes can exhibit different birefringence under cross-polarized filters. A clear majority of natural diamonds exhibit some degree of internal strain, with type II natural diamonds showing a weak “tatami” pattern. HPHT-grown diamonds are free of such strain, and CVD-grown diamonds show mostly coarse columnar patterns.
Most natural diamonds have a strong reaction to long-wave UV; this reaction is usually weaker (mostly blue) at shorter wavelengths. Laboratory-grown diamonds generally exhibit more intense fluorescence with short-wave UV compared to long-wave UV, with a chalky coloring tinged with green or yellow. Most HPHT-grown diamonds also phosphoresce. If a diamond is free of inclusions, fluorescence is a reliable screening test to flag suspicious stones that should be further checked under cross-polarized filters (figure 1).

Figure 1. This chart illustrates the steps in the screening and identification of lab-grown diamonds.
In the case of some rare near-colorless clean CVD-grown diamonds that do not show fluorescence or have a birefringence pattern that is coarse but resembling tatami in type IIa and weak patterns in natural Ia diamonds, additional tests using advanced spectroscopy and strong short-wave UV light to observe growth patterns are needed to confirm diamond genesis. @topic:4


Publish Year: 2018 Title: A Repaired Diamond Abstract: Figure 1. A face-up photo of the repaired diamond. Photo by Robison McMurtry.

A 1.38 ct marquise-cut diamond (figure 1) was submitted to the Carlsbad lab for colored diamond grading services. It was initially noted that large fractures and a large cavity were present on the table. Careful examination of the stone with a gemological microscope revealed that it had previously broken in half and been repaired with an unknown adhesive. The first clue was a large fracture from the crown to the pavilion that showed a sizeable gap present throughout the stone. Furthermore, the facets the fracture passed through all showed slight to moderate misalignment, which cannot happen during polishing (figure 2). Finally, large trapped air bubbles could be seen in the fracture when viewed at an angle. These clues proved that the diamond had broken and been put back together again, though not perfectly. Polish lines on the pavilion facets showed a pattern that would line up if not for the fracture separating them, demonstrating that the breakage occurred after the diamond had been at least partially polished. Beyond that, it is impossible to tell when the damage occurred.

Figure 2. A bezel facet of the repaired diamond as seen in reflected light. The wide fracture can be seen cutting across the facet, and the upper edge of the facet does not form a straight line. Photo by Troy Ardon; field of view 3.3 mm.
Diamonds have been adhered together with glue to form a diamond-diamond doublet (E. Barrie and E. Biermans, “A different type of deception: ‘Diamond-diamond’ doublet,” HRD Antwerp, 2014, www.hrdantwerp.com/en/news/a-different-type-of-deception-diamond-diamond-doublet), but a broken diamond that has been repaired was not something previously reported by GIA. The fracture in the item was not a flat, straight surface but very irregular, indicating that it was not two separate diamonds glued together to make a larger diamond, but rather a repair. Since the item was simply two pieces of diamond joined together, it was not eligible to receive a diamond grading report. None of the 4Cs apply to a composite such as this (e.g., the carat weight of the item was actually the sum of the weights of two diamonds plus the weight of the adhesive). The decision to repair a diamond in this manner is unusual. Careful gemological examination will, however, reveal the repair work done. @topic:10


Publish Year: 2002 Title: Diamonds in Canada Abstract: A newcomer (since 1998) as a supplier of rough diamonds to the world market, Canada is currently the seventh most important diamond producer by weight and fifth by value. This article chronicles the history of the exploration for, and discovery of, primary diamond deposits throughout Canada (538 kimberlites are currently reported), with particular emphasis on the important kimberlite pipes in the Northwest Territories. Typically, these pipes are small but have high diamond grades. Sales of the rough diamonds, and the fledgling cutting and polishing industry in Canada, are described, along with branding initiatives and the marketing strategies of the producers. Canada will become an increasingly significant supplier of rough diamonds as prolific new mines start production, and this will have a growing impact on the world diamond industry.

Read more

	DATA DEPOSITORY

Discredited, Unsubstantiated, and Doubtful Reports of Diamond Discoveries in Canada Before 1963
	Submitted by B. A. Kjarsgaard and A. A. Levinson
	October 30, 2002 @topic:11


Publish Year: 2014 Title: Diamond Laser Abstract: R. P. Mildren, A. McKay, R. J. Williams, and O. Kitzler, “Diamond Raman Lasers,” Optics & Photonics News, Vol. 25, No. 9, 2014, pp. 42–49. Photo by Robert Weldon/GIA.

              Diamond’s extreme properties will fill voids in the laser industry as well as many other optical, mechanical, and electronics technical areas, as advances in chemical vapor deposition (CVD) growth processes erase the scarcity issue of high-purity, high-quality single-crystal diamond. Today, these synthetic diamonds are readily available in sizes greater than 1 cm.

Ideal laser materials can lase at multiple wavelengths, with excellent beam quality and extremely stable power—a combination of characteristics that require durability, transmission through many wavelength ranges, high heat conductivity, low thermal expansion, and efficient conversion of various input powers into desired wavelengths. Diamond, a material first demonstrated as a laser only five years ago, happens to have all of these characteristics to a far greater extent than other bulk crystals. It is also the only known material capable of producing continuous wave (CW), Q-switched, ultrafast lasing ranging from the deep ultraviolet (UV) to the mid-infrared. Diamond is the material that has the potential to bring Raman lasing into the commercial realm.

While diamond’s compact lattice keeps it from functioning as a traditional solid-state laser—large fluorescing dopant cations would disrupt the lattice—it is highly suited as a Raman laser material. Raman lasers rely on efficiently stimulated Raman scattering (an inelastic light-scattering process) rather than stimulated emission from excited dopant ions. This difference opens up access to many wavelengths not accessible from traditional solid-state lasers. In effect, the laser wavelengths achievable are limited by pump wavelength and medium transparency.

Low efficiencies, poor heat management, and limited transparency ranges have plagued the Raman laser materials explored to date, so here is where diamond can really shine. Silicon, a material with the same structure as diamond, was demonstrated as a Raman laser in 2005. There was much excitement over this for the possibility of Si acting as a gain element in on-chip optical processors. But it has less than a tenth of diamond’s thermal conductivity, much lower transparency, less than half of diamond’s Raman shift, and multiple absorption issues throughout much of the wavelength ranges it has been considered for.

Diamond, meanwhile, has unmatched thermal conductivity, transmission range, and hardness, and an intrinsically large cross-section for Raman scattering with a gain coefficient of 10 cm/GW—the top end for all Raman materials. Not only do you get enhanced power and wavelength range with diamond, you get it with lower pump thresholds, using shorter crystals. Diamond has already demonstrated the highest-output CW power for Raman crystals by an order of magnitude, and it approaches the highest power of any Raman laser (in the form of fiber lasers) at 300 W. To surpass this limit and approach the theoretical limit, conversion efficiency by reducing low absorption losses in the near infrared (NIR) will have to be enhanced by improving crystal quality. Therefore, the pressure is still on to produce larger crystals of even higher purity and structural perfection. @topic:4


Publish Year: 1981 Title: Ruby in Diamond Abstract: The first substantiated identification of corundum (var. ruby) occurring as an inclusion in natural diamond is presented. The ruby is assigned to the eclogitic suite of inclusions in diamond, and the implications of its occurrence are discussed in relation to the genesis of "eclogitic" diamonds. It is concluded that diamond crystallizes from a melt over a long period of time with possible fluctuations in ambient temperature and geochemical environment. @topic:8


Publish 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. @topic:4


Publish Year: - 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 aggregated 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 yellowish green fluorescence in the face-up view and blue fluorescence in the face-down view (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 3). Photoluminescence 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 yellowish green fluorescence for the face-up view (top right) and blue fluorescence for the face-down view (bottom right). DiamondView 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 could be observed along the interface layer on the crown facets (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.

	Figure 3. Left: The yellowish green fluorescent top layer was observed in the DiamondView image. Center: 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). Right: The thickness of the CVD synthetic layer is approximately 80 microns. DiamondView image and photomicrograph by Kyaw Soe Moe.

	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.

	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 (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-colored composite diamond indicated that similar challenges could exist for colorless and near-colorless diamonds.

	Read this article in Simplified Chinese or Japanese. @topic:4


Publish Year: - Title: 2019 in Review: Diamond Trade Begins Recovery, Jewelry Retail Blooms Late, Extraordinary Auction Sales Abstract: Cartier fashioned the costliest piece in Christie’s May Maharajas & Mughal Magnificence auction, a Époque-era Diamond Devant-de-Corsage brooch that sold for $10.6 million. Photo courtesy of Christie’s

The world diamond industry continued to contract in 2019 in the wake of oversupplies and tightening credit, but the major auction houses still made headlines with extraordinary offerings. Retail jewelry sales held up as the world economy remained fairly strong, despite being buffeted by the U.S.-China trade war.
Regardless of a decent 2018 holiday season in the U.S., inventories of polished and rough diamonds continued to increase in 2019, causing prices of both to soften to the point where De Beers and Alrosa, the two largest diamond producers, slashed their sales volumes by some 25%. In addition, rough prices declined about 15% on average, especially in the second half of the year, according to a study by Petra Resources, a South African diamond mining company.
Prices and industry profits did not improve, so one of the industry’s leading lenders, ABN AMRO Bank, announced that it would no longer finance rough purchases for goods that can’t be cut profitably – that includes the majority of sizes and qualities below five carats.
ABN AMRO’s restrictions were stringent. It defined “profitable” sales as those that can achieve “real sales margins for goods sold as soon as possible after purchase of rough without considering credit terms.” The bank also said that clients wanting to use its rough buying credit facility need to apply on a case-by-case basis.
By November, total industry credit stood about $8 billion, just over half of the total three years ago and $10 billion below the peak of 2013.

A group of unsorted rough diamonds from the Diavik Diamond Mine in Canada. Photo by Russell Shor/GIA
De Beers and Alrosa, which account for about two-thirds of the rough diamond market by volume and value, reported their rough sales were down about 25% through the first three-quarters of the year. Rough sales by Rio Tinto, the third largest producer, were down more than 15% through the same period, as the company’s diamond division reported a loss for the first half. In November, producers reported the supply situation was improving, with a pickup in demand from diamond manufacturers.
Overall diamond production will likely fall about eight million carats this year from a 2018 total of 148 million carats.
JEWELRY RETAIL
U.S. watch and jewelry sales opened the year with 0.7% decline in January receipts and remained slightly behind 2018 for the first half of the year, according to U.S. Department of Commerce figures. Third quarter demand, however, rose into positive territory, accelerating to a 6% increase in September, compared to the same month in 2018.
Signet Group, which owns Kay Jewelers, Zale and Jared, reported a 2.1% increase in same store sales in the third quarter after struggling with declines earlier in the year. Its online sales rose 11%. In addition, Signet is reducing 50% of the amount of jewelry it purchases from Chinese suppliers because of the increased tariffs on its products.
Tiffany & Co., which is in the process of being acquired by the French luxury group LVMH, reported flat sales for the quarter as reduced tourist traffic in the U.S. has cut business at its flagship New York store and unrest in Hong Kong has deterred shoppers from commercial areas in that city.
In greater China, the protests in Hong Kong, which began in June, cut deeply into revenues. Chow Tai Fook, the largest jewelry retailer in the region, reported that its Hong Kong total sales were down 20% and 28% on a same store basis for the six months ending Sept. 30. Its same store sales on the mainland were up 1.9% for the same period.
In India, the declining rupee has deterred demand for diamonds and gold at retail.
AUCTIONS
The 2019 auction season was neatly divided into two distinct parts: Spring sales were devoted to history and design, while the fall sales saw a return of larger diamonds and rare fancy colored diamonds that had been the houses’ mainstays for the past several years.
The spring auctions had fewer lots and fewer very large and top fancy color diamonds than previous sales as prices eased from the record levels seen a few years ago. Auction executives were quick to point out that the market for high-quality gems and jewels remained robust for gems and jewelry with a historic past.
Rahul Kadakia, Christie’s international head of jewelry, said that April’s New York auction, which had no top fancy colored diamonds (pink and blue especially) over 5 carats or D flawless diamonds larger than 25 carats, “represented the current market.” In addition, a high percentage of lots came from estates, not dealers.
When the market weakens for major gemstones, the auctions have to become more careful, curating their sales to include smaller high-quality stones, more classic “signed” period jewels and more on estate pieces. Prices are usually less aggressive than those from dealers, Kadakia said.
Accordingly, the highlight of the spring auction season was Christie’s Maharajas & Mughal Magnificence jewels from the Al-Thani Collection in May.
Several pieces from the most famous Mughal ruler, Shah Jahan who ruled from 1628 to 1658, drew some of the most intense bidding. The Shah Jahan carved emerald of 30.60 cts, mined in Colombia, sold for $555,000, while his carved spinel and enamel seal ring from 1643 or 1644 brought $795,000. Jahan’s white jadeite dagger, the next to last lot in the sale, sold for $3.4 million, a record for a piece owned by the ruler.
The costliest piece in the auction was a Belle Époque-era Diamond Devant-de-Corsage brooch by Cartier that sold for $10.6 million. This brooch, which contains several large Golconda diamonds, was made in 1912 for Solly Joel, one of De Beers’ founders. The largest diamond in the brooch was a 34.08 ct E VVS1 Type Ia pear shape; followed by a 23.55 ct D VVS2 oval (potentially flawless) Type IIa; a 6.61 ct D VS1 Type IIa marquise cut and a 3.54 ct E VS1 Type I a heart shape diamond. All were graded by GIA.

The Catherine emerald, mined in Colombia over 250 years ago, sold for $4.3 nearly $1 million above its high estimate, at Christie’s May 15 Geneva auction. The emerald, originally a 107 ct square cut, was acquired by Catherine the Great, the Russian monarch, around 1790 and passed through Russian royalty until 1920. The gem was recut in 1954 to remove inclusions. Photo Russell Shor/GIA
The most publicized lot of Christie’s May 15 Geneva auction was surely one-of-a-kind: The Imperial Emerald of Grand Duchess Vladimir of Russia, which originally belonged to empress Catherine the Great.
The emerald’s rich history started when it was acquired as a 107.67 ct square cut by Catherine the Great toward the end of the 18th century. It passed through Russian royalty after her death until Cartier purchased it in 1927. Cartier had the emerald recut into a pear shape of 75.63 cts to eliminate most of the fissures and inclusions, then sold it to John Rockefeller Jr. in 1954.
Christie’s experts listed the pre-sale estimate of $2.3 million to $3.5 million in the catalog. When the bidding ended, an anonymous private buyer paid $4.3 million for the emerald, adding about $1 million for its history.
In the fall season, demand and prices at the extreme top end strengthened.

This GIA-graded Fancy Deep blue 7.03 ct diamond from London jeweler Moussaieff drew a top bid of $11.6 million ($1.65 million per carat) at Christies Nov. 12 Geneva auction. Photo courtesy of Christie's Images Ltd.
Christie's Nov. 12 Geneva auction was 93% sold by lot and 88% by value. The top lot of the sale was the GIA-graded Fancy Deep blue 7.03 ct diamond from London jeweler Moussaieff, which drew a top bid of $11.6 million ($1.65 million per carat), within the pre-sale estimate.
Other large gems that sold were:

A 46.93 ct GIA-graded D IF step cut cushion shape diamond for $3.1 million, ($66,800 per carat), just under the pre-sale estimate
A 25.2 ct GIA-graded D VVS rectangular cut diamond for $2.53 million ($100,595 per carat)
A 42.97 ct Burmese octagon cut sapphire for $2.5 million ($59,000 per carat)
A 13.53 ct Colombian emerald for nearly $1.1 million, a very strong $91,575 per carat

GIA alumna Anna Hu’s Dunhuang pipa Necklace sold for $5.8 million at Sotheby’s Oct. 7 Hong Kong auction. The necklace design features a 100.02 cushion-shaped Fancy Intense yellow diamond showcased in the shape of a Chinese musical instrument – Dunhuang pipa – and embellished with variously shaped and brilliant-cut diamonds mounted in 18K white and yellow gold. The pipa can be detached and worn as a pendant/brooch. Photo by Michael Oldford. Courtesy of Sotheby’s
In addition, a jeweled piece designed by GIA alumna Anna Hu on commission from Sotheby’s, drew a winning bid of $5.8 million at the auction house’s Oct. 7 Hong Kong sale. The necklace features a GIA-graded 100 ct Fancy Intense yellow diamond set in the shape of a Dunhuang pipa, a traditional four-stringed Chinese musical instrument that is depicted in an ancient mural in Dunhuang.
Sotheby’s May 14 Geneva sale saw one large D fl (36.57 cts) sell for about $5 million ($136,000 per carat) but most of the action was for signed period jewels, such as The Beaumont Necklace, a Van Cleef & Arpels Art Deco emerald and diamond creation that sold for $3.6 million, about 20% above its estimate.

The Beaumont Neckalce, a circa 1935 Art Deco emerald and diamond creation, presumably made by Van Cleef & Arpels for American socialite and collector Hélène Beaumont, sold for $3.6 million at Sotheby’s May 14 Geneva auction. Courtesy of Sotheby’s
DIAMOND TRACKING
There were a number of new diamond origin tracking services introduced at the JCK Las Vegas show in June. In addition to the GIA Diamond Origin Report, De Beers and Alrosa introduced their own mine-to-market diamond tracking; the Cullinan Diamond Report debuted as an identification system to track high-value, previously mined diamonds; and Sarine offered a service charting a diamond’s progress through the cutting processes.
LABORATORY-GROWN
The market for laboratory-grown diamonds continued to expand. About 50 companies exhibited at the JCK Show in Las Vegas, which was substantially up from last year, but prices were significantly lower ‒ 30% to 40% of comparable quality natural diamonds. This led to intense speculation about where this market was heading.
Forecasters like Bain & Co predict that laboratory-grown diamonds will account for about 15% to 20% of sales in five years, and this year they may have taken a long stride toward that goal. Analysts estimate that about 2 million carats of laboratory-grown diamonds will be produced this year. Since companies do not reveal their sales, it is impossible to know how many of these reached consumers.
In comparison, production of the 140 million + carats of natural diamond rough sold this year resulted in an estimated 25 to 30 million carats of polished natural diamonds. (This is calculated by noting that about 50% to 55% of rough mined is industrial and the remaining 70 million carats is cut to an average 35% to 40% yield). @topic:7


Publish Year: 2015 Title: HPHT Synthetic Diamond Melee in High-Quality Jewelry Piece Abstract: Figure 1. A photo and a detailed illustration of the melee-set pendant show the location of all 118 samples. The single HPHT synthetic melee is highlighted in both images. Photo by Jian Xin (Jae) Liao.

Advances in the laboratory growth of diamonds have led to an increase in the number of synthetic diamonds seen at GIA. The existence of high-quality synthetic diamonds in melee sizes is of particular concern. This is due in part to the expense of examining melee relative to their value. While GIA can reliably identify synthetic melee, this requires individual analysis of each stone, preferably before mounting. In a complicated piece with hundreds of melee, this can be prohibitively expensive or time-consuming. The same is true for melee parcels. A synthetic diamond mixed into a packet may not be identified until later, deceiving dealers, jewelers, and consumers and potentially causing damage to the trade.

Recently, a pendant with 118 mounted stones was submitted to GIA’s New York laboratory for color origin analysis of each individual melee (figure 1). The pendant consisted of a central pear-shaped stone surrounded by three consecutive rows of round brilliant melee. Of the 118 stones, 58 were fancy yellow, including the center stone, and 60 were colorless. Using a Fourier-transform infrared (FTIR) microscope in reflection mode allowed detailed focusing of the infrared beam on the mounted stones, including those that were partially obscured. Analysis was carried out on a Thermo Nicolet iN10 FTIR microscope, which determined the diamond type classification of each melee stone from its mid-IR absorption spectra (C.M. Breeding and J. E. Shigley, “The ‘type’ classification system of diamonds and its importance in gemology,” Summer 2009 G&G, pp. 96–111). One melee was identified as an HPHT-grown (high-pressure, high-temperature) synthetic diamond, based on its infrared spectrum as well as its color, fluorescence pattern, and phosphorescence behavior. This 0.00431 ct melee was removed from the setting to confirm its origin as HPHT-synthetic. The rest were confirmed as natural diamonds.

Of the 118 melee, 114 were classified as type IaA or type IaAB. These were characterized by absorption from aggregated nitrogen centers, where A-centers (nitrogen pairs) and B-centers (four nitrogen atoms symmetrically surrounding a vacant lattice site) absorb infrared light at 1282 and 1174 cm–1, respectively. These spectra revealed sufficient A-center concentrations, eliminating the possibility of HPHT treatment, which would have deaggregated the centers into isolated nitrogen atoms (A.T. Collins, “The colour of diamond and how it may be changed,” Journal of Gemmology, Vol. 27, No. 6, 2001, pp. 341–359). Since A- and B-center absorptions occur solely in the infrared range, their presence does not produce color. Instead, the yellow color observed in 57 of these type IaA/IaAB stones resulted from absorption from the N3 defect at 415 nm (a complex of three nitrogen atoms surrounding a vacancy) and associated peaks at 453, 452, 465, and 478 nm. This spectrum is known as the “Cape series,” and such goods are commonly referred to as “Cape yellow.”

Two colorless stones were classified as type IaB, showing only pure B-aggregate absorption; the remaining colorless stone was type IIa, meaning it did not show IR absorption from any nitrogen-related impurities. Finally, a partially obscured yellow stone near the bottom of the piece was type Ib, showing absorption due to isolated nitrogen impurities, and characterized by features at 1130 and 1344 cm–1. Isolated nitrogen centers also produce a broad absorption feature in the UV-visible range (approximately 270 nm), resulting in a coloration often described as “Canary yellow.” Type Ib diamonds are very rare, representing only 0.1% of all natural diamonds (R. Tappert and M.C. Tappert, Diamonds in Nature, Springer, Berlin, 2011). Conversely, this diamond type is common in yellow synthetic diamonds. Due to the absence of A-centers, these four samples required further testing.

Photoluminescence spectroscopy confirmed that the type IaB and IIa stones were natural in origin. However, the type Ib stone (marked in figure 16) was further examined with DiamondView imaging, which showed that it exhibited strong yellow-green fluorescence under deep ultraviolet illumination (wavelength 230 nm) and indicated growth sector patterns typical of HPHT synthetic diamonds, as well as strong blue phosphorescence inconsistent with natural yellow type Ib diamonds (J.E. Shigley et al., “A chart for the separation of natural and synthetic diamonds,” Winter 1995 G&G, pp. 256–264; J.E. Shigley et al., “Gemological properties of near-colorless synthetic diamonds,” Spring 1997 G&G, pp. 42–53). The 0.00431 ct yellow stone was removed from its mounting for more comprehensive examination with the DiamondView (figure 2). Its cuboctahedral synthetic growth sectors were clearly seen from both the table and pavilion, confirming its HPHT synthetic origin.

Figure 2. Left and center: DiamondView fluorescence images of the 0.00431 carat type Ib diamond show clear cuboctahedral HPHT synthetic growth sectors. Right: The sample’s strong phosphorescence is atypical for a diamond of this type and color. Images by Martha Altobelli.
Although this could have been an isolated event, it underscores the need for caution when buying melee parcels or mounted pieces from unfamiliar sources. Nevertheless, it is important to note that such stones can be unequivocally identified as lab-grown. Colorless and near-colorless (D–N) unmounted diamonds larger than 0.01 ct can be tested using commercially available testing equipment such as the GIA DiamondCheck. Meanwhile, colored diamonds, smaller stones, and mounted jewelry need to be tested by a reputable gemological laboratory. Increased industry awareness, combined with diamond testing, may deter the spread of undisclosed synthetics, ultimately benefiting both sellers and buyers of polished diamond goods. @topic:4


Publish Year: 2017 Title: A Review of HPHT Synthetic Diamonds Grown forJewelry Use Abstract: Our Fall issue serves up a wealth of topics, including HPHT synthetic diamonds, historical saltwater pearls from the New World, the photoluminescence (PL) spectra of emeralds, synthetic star corundum, and the Colombian emerald mine-to-market industry.

HPHT synthetic diamonds—including blue and colorless gems exceeding 10 carats along with mass-produced melee—are now a marketplace reality...

In our lead article, Drs. Sally Eaton-Magaña, James Shigley, and Christopher M. Breeding present a comprehensive study of several thousand HPHT-grown synthetic diamonds using data gathered by GIA between 2007 and 2016. Their study charts a transition from predominately orange-yellow goods to today’s more diverse products, where fashioned blue and colorless synthetics exceeding 10 carats and mass-produced HPHT melee grown exclusively for jewelry use are now a marketplace reality. We trust that this survey—which includes a review of current identification criteria for HPHT-grown synthetics—will prove immensely valuable for industry professionals.

The second paper is a collaboration between researchers at GIA and the Gübelin Gem Lab. Lead author Chunhui Zhou and his team detail 85 natural saltwater pearls reportedly recovered from Caribbean waters between the fifteenth and seventeenth centuries. The team’s analyses verified these fascinating pearls’ natural saltwater origin, and 14C isotope radiocarbon dating supports their attested age.

In the first of this issue’s two emerald papers, researchers led by Dr. D. Brian Thompson of the University of North Alabama investigate the PL spectra of 48 samples from Colombia, Afghanistan, and Zambia. Their research strongly indicates that variations in trace element concentration within emeralds from these localities correlate with differences in the strength and position of peaks detected in their PL spectra, which could be very promising for determining geographic source.

In our fourth paper, Dr. Karl Schmetzer, Prof. H. Albert Gilg, and Dr. Heinz-Jürgen Bernhardt delve into the characteristics of synthetic star corundum produced in Germany up to the 1970s by Wiede’s Carbidwerk. Grown by a variation of the Verneuil method followed by controlled annealing to exsolve the rutile needles, these synthetic gems are visually—and gemologically—distinct from the production of other manufacturers.

Next, Tomasz Powolny and Dr. Magdalena Dumańska-Słowik reexamine spotted “dalmatian jasper,” a popular decorative gem material. Based on their analysis of its composition and gemological characteristics, which do not meet the definition of jasper, the authors recommend use of the term “dalmatian stone.”

In our final article, Darwin Fortaleché, chief gemologist at Centro de Desarrollo Tecnológico de la Esmeralda Colombiana (CDTEC), and his GIA coauthors provide a comprehensive field report on current mining and the state of the Colombian emerald industry. They cite increased investment by multinational companies, the country’s largely untapped emerald reserves, and the initiation of chain-of-custody systems as hopeful signs for the future.

Our Lab Notes section features an entry on a large, high-quality diamond from Brazilian kimberlite. Topics in our Micro-World section include hematite roses and a “flower-in-the-rain” inclusion within a Sri Lankan sapphire, while our Gem News International section spotlights blue-green pyrope-spessartine with high vanadium content and two potential new sources of Nigerian sapphire.

Please enjoy the Fall G&G! @topic:10


Publish Year: 2017 Title: HPHT Synthetic Diamond Melee Found In Mounted Jewelry Abstract: Figure 1. Among the 70 melee diamonds mounted in this ring, one was confirmed to be an HPHT synthetic diamond. Photo by Johnny Leung.

Separation of treated and synthetic diamond melee from natural diamond is challenging work. Diamond melee, which weigh less than 0.2 ct, are often submitted to gemological laboratories in parcels containing hundreds (or more) loose stones. GIA’s automatic screening device, introduced in 2016, can separate synthetic and treated diamond melee from natural diamond melee. Identification becomes more challenging when the melee are mounted, due to their small size and the difficulty of accessing them.

In late February 2017, GIA’s Hong Kong laboratory received a ring containing 70 melee in addition to a marquise-cut diamond center stone (figure 1). Using a prototype of GIA’s new screening device for mounted gems, 69 of the melee passed the test for natural diamond, and one was referred as possible treated or synthetic diamond. The stone in question, which was set next to the center marquise diamond (figure 2, left), had no apparent inclusions. Infrared absorption spectroscopy identified it as a type IIb diamond with an absorption band at 2800 cm–1, indicating the presence of boron as a defect, forming a local vibration mode. Using photoluminescence (PL) spectroscopy, a very strong doublet peak at 882/884 nm related to nickel impurity was recorded under laser excitation and low temperature. The NV– center was more prominent than the NV0 center. Strong blue phosphorescence was also detected (figure 2). These observations confirmed that this was an HPHT synthetic diamond, very similar to melee we have previously tested that were manufactured in China.

Figure 2. Set near the center marquise diamond, one melee diamond (left, in red circle) showed the blue fluorescence (center) and phosphorescence (right) characteristic of HPHT synthetic diamond. Photos by Johnny Leung (left) and Terry Poon (center and right).
How to screen jewelry items with mounted diamonds for quality control is a concern in the industry. GIA’s robust instrument for rapid and accurate screening of small diamonds set in mountings will be available in late 2017. @topic:4


Publish Year: 2008 Title: Identification of Melee-Size Synthetic Yellow Diamonds in Jewelry Abstract: Melee-size yellow synthetic diamonds have recently been seen in the gem market, mostly as loose stones but sometimes set in jewelry. The material identified to date is synthesized by the high-pressure, high-temperature (HPHT) process. Randomly occurring pinpoint or flux-metal inclusions are diagnostic identification clues. However, some synthetic diamonds require advanced laboratory methods. This report describes the effectiveness of a technique new to gemology, infrared microspectroscopy, in combination with cathodoluminescence imaging for the rapid and accurate separation of melee-size natural and synthetic diamonds based on their characteristic mid-infrared absorption spectra and growth structures, respectively. With these techniques, the GAAJ-Zenhokyo Laboratory in Tokyo determined that approximately 10% of loose—and dozens of mounted—yellow melee diamonds submitted over a four-month period were synthetic. @topic:4


Publish Year: 1990 Title: An Investigation of a Suite of Black Diamond Jewelry Abstract: This article reports on the gemological properties of six large black diamonds set in a suite of jewelry. The color of the diamonds was determined to be caused by numerous black inclusions lining cleavages and fractures. Such stones are difficult to cut and polish, and require great care in setting. They can be separated from artificially irradiated dark green black-appearing diamonds and from other black and black-appearing materials on the basis of their distinctive visual and gemological features. @topic:10


Publish 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. @topic:2


Publish Year: 2020 Title: Ethical Gem Fair Abstract: Figure 1. A selection of gemstones from Anza Gems. All of these stones were sourced in Tanzania, including the set of rough sapphires that was mined in Tanga province. Each stone can be traced back to the individual miner who unearthed the gem. Photo by Kevin Schumacher.

Tucson’s first Ethical Gem Fair, a platform for responsibly sourced gemstone suppliers to highlight their products and projects, was held February 3–6 at the Scottish Rite Cathedral. This was the first Ethical Gem Fair in the United States after being held in London and Edinburgh the last three years.
The Tucson event was a collaboration between suppliers Nineteen48, Capricorn Gems, Perpetuum Jewels, Nature’s Geometry, Agere Treasures, Columbia Gem House, and Anza Gems. They share a commitment to supply chain ethics, mine-to-market traceability, environmental and health and safety regulations, and supporting artisanal miners and communities.

	Monica Stephenson, founder of Seattle-based Anza Gems

Monica Stephenson, founder and president of Seattle-based Anza Gems, said her travels to East Africa to purchase rough have shown her that miners need to be educated about the value they bring to the supply chain. Ten percent of Anza’s proceeds go to education at the mining communities.
Anza Gems is a partner of Moyo Gemstones, a responsibly sourced gemstone program that was sparked by GIA’s artisanal mining education program. The pilot effort, a collaboration between GIA, Pact, and the Tanzania Women Miners Association (TAWOMA), focused on women miners in Tanga, Tanzania. After initial training, they were more knowledgeable about the mined gemstones but lacked a platform to bring them to the market. Stephenson saw potential here, and together with Pact and TAWOMA she founded Moyo Gemstones. The program provides a marketplace for gemstone transactions, offers free occupational health and safety training, and helps ensure that all miners are legally registered.
Stephenson said that before the program these miners would get a few dollars for gems from a broker, with no visibility into their value in the supply chain. Moyo has changed this through education. “For the miner to understand what she has and the value of those gems, and also to be taking home more like 95% of the export price, and pay her broker, is a complete reversal of the roles,” Stephenson said. “This is truly a paradigm shift in this region. For her to have the income and financial sort of independence is enormous.”
Each gem can be traced back to the miner, Stephenson said, and it’s important to share that story with the consumer. “They need to know that what they’re buying not only makes a difference, and not only does it not cause harm, but it actually is beneficial.”
Anza Gems’ offerings (figure 1) included sapphire, multiple colors of garnet, tourmaline, citrine, amethyst, zircon, and Mahenge spinel.

	Brian Cook, owner of Nature’s Geometry in Tucson

Brian Cook, owner of Nature’s Geometry (Tucson), began selling crystals as a geology student almost 30 years ago. This took him to a remote area of Bahia, Brazil, where rutilated quartz is mined. He felt a strong connection to the place and made it his second home. Since then he has advocated for the development of resources more sustainable than mining so the community can rely on them when mining ends.
Cook told us about their project in Bahia to benefit the artisanal mining community. The first initiative will raise funds for dust masks for the miners, at least half of whom have no dust protection for underground mining. Second, he envisions a model of investment in regenerative agriculture to create food security, improve nutrition, and implement carbon sequestration. The area’s soil is so rich that it allows for farming of crops such as cacao, coffee, acai, and many others. The third component will be teaching lapidary skills.
Eighty percent of colored gemstones are mined by small-scale and artisanal miners, according to Cook. “This project could serve as a model for our industry at large,” he said. While he recognizes that every situation is different, food, water, and energy will always be the basic needs of every being, and guaranteeing them can uplift a community.

Figure 2. Rough rutilated quartz from Bahia, Brazil. Photo by Kevin Schumacher.
Cook showed us several pieces of rutilated quartz from Bahia, including a sizable piece of rough (figure 2). Nature’s Geometry has been cutting the material since 1989. Each piece is unique, which Cook said is something the younger generation likes.
Cook said the response to the fair has been “phenomenal.” He predicts it will grow in future years, with more vendors and a greater variety of stones.

	Ian Bone, manager of Capricorn Gems in Australia

Ian Bone, manager of Capricorn Gems (Central Queensland, Australia) said the Ethical Gem Fair was created to meet the needs of designers and customers who want a gemstone’s mine-to-market story. “There’s undoubtedly a generational shift happening,” he said. “Customers want to know that the pieces are brought to market in the most responsible manner possible. We see this as the cutting edge of jewelry design and in fact the future of the jewelry industry.”
Bone said that because Australia’s mining industry already has strong regulations for safety, the environment, energy, and land reclamation, it could serve as an example for other mining communities around the world.

Figure 3. Capricorn Gems’ chrysoprase from Marlborough, Central Queensland. Photo by Kevin Schumacher.
Bone, a Central Queensland native, has built his business around local gemstones: boulder opal, chrysoprase, zircon, and sapphire. He is able to witness the entire process, from mining to cutting to consumer sales. He showed us a selection of chrysoprase from Marlborough, Central Queensland (figure 3). “Marlborough has some of the best chrysoprase in the world,” he said. “Chrysoprase is an unusual gem because you can get a whole set of qualities of that stone, from dollars a pound up to dollars a carat.”
Bone said Capricorn Gems is breaking down boundaries between sourcing, production, and sales. They share their images, videos, and stories of mining with designers for use in their own marketing. One example is a booklet showcasing the works of designers around the world who use stones from Capricorn Gems. “The client knows that their designer knows and trusts the gem supplier and knows where that material comes from,” he said.

Figure 4. Ethiopian opal from Agere Treasures. Photo by Kevin Schumacher.

	Hewan Zewd, founder of Agere Treasures in Lynnwood, Washington

Hewan Zewdi, founder of Agere Treasures (Lynnwood, Washington), was born and raised in Ethiopia and moved to Seattle 14 years ago. There she earned her G.G. through GIA Distance Education. When Ethiopian opal (figure 4) was discovered in 2008–2009, people began calling from home to ask if she had a market for them. “That’s what I study—that’s what I want to do,” she told them.
At the Denver Gem & Mineral Show, Zewdi’s first trade show, she saw Ethiopian opal dealers undervaluing their material and advised them to increase their prices. She also began buying stones from them to sell in her local market in Washington. Her commitment increased when emeralds were discovered in southern Ethiopia. Agere Treasures now offers opal, emerald, amazonite, yellow labradorite, garnet, zircon, tourmaline, and sapphire.
Part of Zewdi’s profits go to a new project to train young women in basic gemology and jewelry design. She also donates books on rocks and gems to the Ethiopian Ministry of Mining, and she assists the organization in obtaining gemstone identification at GIA so the stones can be priced accordingly by exporters in Ethiopia.
“Here everybody has the same mission, the same vision,” Zewdi said of the Ethical Gem Fair. “To give back and get the material traceably and responsibly, without hurting the environment or the artisanal miner, by creating a fair trade and a fair price.”
Buyers at the Ethical Gem Fair were younger people and designers looking for a stone with a story. They want to know about the supply chain for almost every product they use, including jewelry. The show’s suppliers offer as much transparency as possible to their customers, often providing supporting information about the stones, such as images from the mines and cutting factories. Everyone involved in the show sees a growing demand for responsibly sourced gemstones.
Articles on two other exhibitors, Perpetuum Jewels and Columbia Gem House, can be found in the Spring 2019 G&G. @topic:11


Publish Year: 2021 Title: Mignone Halls of Gems and Minerals Abstract: Figure 1. One of the two giant amethyst geodes displayed at the entrance of the Mineral Hall. This geode weighs 11,000 lbs. (5,000 kg). Photo by Augusto Castillo.

The American Museum of Natural History in New York City has reopened one of the most beloved spaces for gem enthusiasts with the unveiling of the Allison and Roberto Mignone Halls of Gems and Minerals on June 12, 2021. After a four-year closure, the 11,000-square-foot halls, which house more than 5,000 specimens sourced from 98 countries, have been completely redesigned and reinstalled to tell the intriguing story of how mineral diversity arose on our planet. This exciting public event reflects the reopening of New York City.
The American Museum of Natural History has a long-standing history with minerals and gems that dates back to its founding in 1869. In the 45 years since the previous iteration of the gem and mineral halls opened, the scientific fields of mineralogy and geology have advanced significantly, and the new design reflects these advancements. The halls were organized by Dr. George E. Harlow, curator of the Department of Earth and Planetary Sciences, to showcase to the public the current scientific understanding of gems and minerals, the geological conditions and processes by which they form, and introduce the relatively novel concept of mineral evolution.

Figure 2. The Singing Stone is a massive 7,200 lb. (3265 kg) block composed of the copper ore minerals azurite and malachite. Its name comes from the high-pitched sounds produced when the stone absorbed and released moisture from the air. The stone no longer sings now that it sits in a controlled environment. Photo by Augusto Castillo.
Mineral evolution, one of the central themes, seeks to explain how more than 5,500 mineral species came into existence when there were no minerals for hundreds of millions of years after the Big Bang. The new halls show how changing conditions on Earth allowed more chemically diverse minerals to arise. They highlight one of the most important changes, which is the evolution of life that filled the atmosphere with free oxygen, enabling colorful, highly oxidized minerals. These are the same colorful minerals we associate with the gemstones humans have used to decorate themselves for thousands of years.
The redesigned space no longer resembles a simulated subterranean mine, with the multi-leveled carpeted interior that the previous iteration was known for. Instead, an open-floor concept allows visitors to wander seamlessly between the different displays and exhibits. It has three main divisions: the Mineral Hall, the Gem Hall, and the Melissa and Keith Meister Gallery for temporary exhibitions.

Figure 3. A towering 14,500 lb. (6,577 kg) slab studded with giant garnets. The garnets formed more than 1 billion years ago, when the original rock transformed at pressure 8,000 times greater than atmospheric pressure and at about 1500°F (815°C). Photo by Augusto Castillo.
Entering the Mineral Hall, the visitor is welcomed by a pair of towering amethyst geodes that formed nearly 135 million years ago (figure 1). The scale and rich purple color of the massive geodes command attention and set the tone for the rest of the space. Behind the geodes, the center of the Mineral Hall contains mineral specimens organized by formation environment: igneous, pegmatitic, metamorphic, hydrothermal, and weathering. Highlights include the Singing Stone, a massive block composed of blue azurite and green malachite that was collected in 1891 from Bisbee, Arizona (figure 2), and a 14,500 lb. slab from upstate New York that is studded with garnets measuring up to one foot across (figure 3).

Figure 4. The 563 ct Star of India, the world’s largest gem-quality blue star sapphire. Photo by D. Finnin/©AMNH.
The west wall of the Mineral Hall has a running display dedicated to the systematic classification of minerals. The display contains 659 specimens arranged by chemical composition, increasing in complexity across the wall. An interactive periodic table that can be used to explore forming minerals stands at the center of the west wall. The four corners of the Mineral Hall explore the overarching scientific concepts of minerals, from their evolution and diversity to their properties and how they have been used by humans from prehistory to the present day. Adjacent to the gallery of minerals and light is the Gem Hall. It features a dazzling display of nearly 2,500 objects, including precious stones, carvings, and jewelry from the museum’s world-class collection. Highlights include the 563 ct Star of India (figure 4), the largest gem-quality star sapphire known, and the 632 ct Patricia emerald, the largest gem-quality emerald reported from the Chivor mine in Colombia (figure 5).

Figure 5. The 632 ct Patricia emerald, discovered in 1920 by a local miner, is the largest gem-quality emerald reported from the Chivor mine in Colombia. Photo by D. Finnin/©AMNH.
In addition, the Melissa and Keith Meister Gallery is a rotating exhibit gallery newly added to the Halls of Gems and Minerals. Beautiful Creatures, curated by jewelry historian Marion Fasel, features animal-themed jewelry created over the last 150 years. The exhibit included more than 100 jewels from the world’s great jewelry houses organized into three categories: land, water, and air. Its time frame coincides with the founding of the American Museum of Natural History in 1869 and explores the extraordinary diversity of the animal kingdom and the inspiration that it has provided for jewelry designers. Beautiful Creatures is on display through September 19, 2021. @topic:8


Publish Year: 2020 Title: Manufactured Inclusions in Gem Materials Abstract: Figure 1. This 47 ct cabochon was creatively carved from the back, and the hollow cavity was then filled with a yellow and red composite material to highlight the floral inclusion. Photo by Robert Weldon; courtesy of Mike Bowers.
Inclusions in gems have gained popularity as social media has exposed collectors to a wide range of gem materials with interesting inclusions. As a result, there has been an increase in artificial inclusions in natural rock crystal quartz as predicted by E. Skalwold (Summer 2016 Micro-World, pp. 201–202). Recently, the authors had the opportunity to examine several unique gems with manufactured inclusions. Microscopic examination revealed that the main methods for manufacturing inclusions were carving, assembling, dyeing, three-dimensional internal laser engraving, or a combination of these methods.

Figure 2. Tool marks from a rotary abrasive burr are clearly visible in this manufactured floral-shaped inclusion (left; field of view 9.72 mm). The cavity was subsequently filled with a yellow and red composite material consisting of sand grains and a colored binder or resin material (right; field of view 4.26 mm). Photomicrographs by Nathan Renfro; courtesy of Mike Bowers.
A 47 ct rutilated quartz cabochon exhibits an eye-catching yellow and red floral-shaped inclusion produced by creative carving and filling with a colored composite material (figure 1). Microscopic examination revealed circular marks from a rotary abrasive tool used to create the intricate cavity (figure 2, left). The cavity was subsequently filled with a yellow and red composite material of fine sand grains and a colored binder or resin (figure 2, right).

Figure 3. This 226 ct round tablet of quartz contains an orange and yellow resin-filled fracture that convincingly imitates natural iron oxide mineral staining in quartz. Photo by Robert Weldon; courtesy of Mike Bowers.

Figure 4. A fracture in this rock crystal quartz has been filled with orange and yellow resin to give the appearance of natural iron oxide staining. Trapped gas bubbles make this manufactured inclusion readily identifiable. Photomicrograph by Nathan Renfro; field of view 8.94 mm. Courtesy of Mike Bowers.
Another creatively manufactured inclusion in a quartz gem can be seen in a 226 ct round tablet containing a large fracture (figure 3). The fracture was filled with colored orange and yellow resin, which resembles natural iron oxide epigenetic staining sometimes seen in rock crystal quartz. A quick examination in the microscope revealed incomplete filling and trapped gas bubbles in the colored resin (figure 4), making the separation between this manufactured inclusion and its natural counterpart quite easy.

Figure 5. This 109 ct polished block of quartz has been assembled from two halves that contain numerous fractures filled with green resin. They have been glued together so that the moss-like inclusion is completely enclosed in the colorless quartz. Photo by Robert Weldon; courtesy of Mike Bowers.

Figure 6. This moss-like inclusion results from a fracture network in two pieces of rock crystal quartz filled with green resin and glued together to encapsulate the inclusion. The assembly plane of the two quartz halves is clearly visible on the side of the stone (left; field of view 18.80 mm). The green resin contained trapped gas bubbles, and the fractures displayed an unnatural striated appearance suggesting they were artificially induced (right; field of view 2.59 mm). Photomicrographs by Nathan Renfro; courtesy of Mike Bowers.
Creative dyeing also produced the manufactured inclusion in a 109 ct quartz with a completely enclosed green moss-like inclusion (figure 5). This stone consists of two pieces of rock crystal quartz, each with a centralized network of fine fractures that may have been artificially induced by laser, judging from their unnatural irregular pattern and striated appearance. The fracture network in each piece was subsequently filled with a dark green resin to give the appearance of a moss-like inclusion. The two halves were then glued together with colorless cement, completely enclosing the green moss-like inclusions in water clear rock crystal quartz. This left a somewhat obvious assembly plane (figure 6, left) when examined with the microscope, as well as trapped gas bubbles in the green resin-filled areas (figure 6, right).

Figure 7. This 724 ct rock crystal quartz contains two manufactured inclusions induced by a 3D subsurface laser-engraving process. Photo by Robert Weldon; courtesy of Mike Bowers.

Figure 8. These stellate inclusions result from 3D subsurface laser engraving, which creates light scattering micro-fractures in a controlled pattern. These represent the latest advancement in manufactured inclusions within gem materials. Photomicrograph by Nathan Renfro; field of view 23.50 mm. Courtesy of Mike Bowers.
The fourth example of manufactured inclusions recently examined is a 724 ct quartz crystal with a polished face that contains two white stellate inclusions consisting of numerous radial arms surrounding a spherical core structure (figure 7). Closer examination revealed a carefully layered series of micro-fractures consistent with 3D subsurface laser engraving (figure 8). This is by far the most technologically advanced example of a manufactured inclusion in a gem material examined by author NR.
While these four examples of manufactured inclusions may not be quite as sought after as gems with natural inclusions, they certainly can be appreciated for the efforts and techniques employed by the manufacturers. Obviously, collectors of gems that feature inclusions should be aware that manufactured inclusions such as those described here exist in the trade. While some manufactured inclusions may be intended purely as an artistic enhancement, others may be produced with the intention to deceive the consumer, and caution should be used if a manufactured origin is suspected. @topic:3


Publish Year: 1987 Title: Infrared Spectroscopy in Gem Identification Abstract: Infrared spectroscopy is a powerful tool for gem identification and research. Absorptions of a gem material in the infrared region of the electromagnetic spectrum are due to vibrations in the crystal structure; they can be used to help separate one gem material from another or to detect certain types of treatments. The authors describe the new Nicolet 60SX Fourier transform infrared spectrometer recently acquired by GIA's Research Department, and outline the detection of polymer-impregnation of opal as an example of the use of infrared spectroscopy in gemology. @topic:8


Publish Year: 2018 Title: Gem Localities and Formation Abstract: Figure 1. Cobalt-blue gem spinel from Baffin Island, Nunavut, Canada. Photo by Lee Groat.

Scientific Study of Colored Gem Deposits and Modern Fingerprinting Methods
Lee Groat
University of British Columbia, Vancouver, Canada
Most colored gemstones form near the earth’s surface in a wide range of different environments; for example, they can crystallize from igneous magmas or hydrothermal solutions, or via the recrystallization of preexisting minerals during metamorphism. The specific environment determines the types of gem minerals that form, as well as their physical and chemical properties. Field studies of colored gem deposits provide the basis for the scientific understanding of natural gemstone formation and, in turn, the basis for criteria for gem identification.
Gem deposits are of scientific interest because they represent unusual geologic and geochemical conditions; for example, emeralds are rare because they require beryllium and chromium (and/or vanadium), which generally travel in very different geochemical circles. Scientists study gem deposits by collecting rock and mineral samples in the field, mapping geological formations and structures, documenting the environment in which the gems occur, and examining the collected samples back in the laboratory. Such examination yields information on the chemical, temperature, and pressure conditions of gem formation, the associated minerals (often found as distinctive inclusions in the gems themselves), and the age of the deposit. Determining the origin of a gem deposit usually requires a small amount of very specific data. The results are published in publicly available peer-reviewed publications. Such field studies provide clues that can be used to explore for similar types of gem deposits. Challenges include the remoteness of locations that have not been previously studied by geologists, the small size of deposits that precludes study by large mining companies, and the rarity of the gems themselves.
There is much left to do in gem deposit research. For example, despite its growing popularity as a gemstone, there are few studies of gem spinel deposits, especially cobalt-blue spinel (figure 1), for which only one deposit has been studied. To date we know little about what factors control spinel genesis and color.
Recently there has been another reason to study gem deposits: gem fingerprinting, in which modern methods are used to obtain characteristic information. This information is then compared to information obtained from stones from known localities to estimate where a stone with no locality information originated.
Modern fingerprinting methods analyze the chemistry of the stones (using electron probe microanalysis, isotopic analysis, laser ablation–inductively coupled plasma–mass spectrometry) and/or their solid and fluid inclusions. We know that the chemistry of the stones must reflect the chemistry of the host rock environment; for example, the chromophore in emerald from Lened in Canada is vanadium, and not the typical chromium, because there are no chromium-bearing rocks in the area. With respect to solid inclusions, rubies from Aappaluttoq in Greenland have phlogopite mica inclusions because they recrystallized in a rock at pressures and temperatures where phlogopite is the stable potassium-bearing phase. An example of diagnostic fluid inclusions is the three-phase variety seen in Colombian emeralds (and now also observed elsewhere). New is the use of ICP-MS on fluid inclusions to define part of the fluid assemblage from which the stones were formed; this tells us about the environment of formation, but also may assist in defining a fingerprint for the stone.
Where scientific studies require only very specific data, the more data available from stones of known origin, and the more representative those stones are of the full range of compositions and inclusions found in a specific deposit or country of origin, the more accurate the estimation should be. Unfortunately, these data are generally not made public, so every lab doing fingerprinting is essentially working independently, and there is no way to know how accurate their data and the resulting country- or deposit-of-origin estimates are. We also note that a serious problem in origin determination is that some of the best gemstones will be lacking diagnostic inclusions altogether, which then restricts the tools and observations can be used.
Gem Pegmatites of Ukraine, Russia, Afghanistan, and Pakistan: An Update on Recent World-Class Finds
Peter Lyckberg
National Museum of Natural History, Luxembourg
Soviet-era exploration and mining of some 1,900 chamber pegmatites on the western endo-contact of the 1.7 Ga Korosten Pluton in Ukraine for piezo quartz left an underground mine with 110 km tunnels reached by six shafts. Since 1995, increasingly intensified study of old pockets and documentation by Vsevolod Chournousenko, chief geologist of Volhyn Kvarts (Quartz) Samotsvety Company, has revealed new targets. Work on these targets has produced gem-quality beryl and topaz, the latter in record-size crystals up to 230 and 325 kg. Topaz occurred in around 10% of mined pockets.
For the first time in the history of the huge deposit, the “Peter’s Dream Pocket” was found and exploited from January 2013 through January 2014. It contained bicolor topaz still in situ growing on cleavelandite, associated with zinnwaldite and smoky quartz. The largest topaz, at 325 kg, was named dedushka (grandfather). The Skorkina pocket in the mine was also called “Vsevolod’s Pocket” after the extraordinary chief geologist who found the topaz mineralization, which yielded a record amount of gem topaz crystals. These came from a depth of 6 to 15 m under the floor, where previous Soviet quartz mining efforts had missed them. The largest of these, the cognac-colored “Sergei” (named after the mine owner), weighs 230 kg and is the largest of its kind. Gem-quality bicolor topaz in large sizes, found particularly in shaft 3 and in open pits in the south and north end of the pegmatite field, is unique to this mine. Extraordinary heliodor crystals were mined in Soviet times, and a smaller quantity mined later yielded faceted stones up to 2,500 ct. A recently mined deep cognac-colored cut topaz weighed 9,000 ct. Natural blue and bicolor topaz (figure 1) have been cut to unique stones, also of large sizes. The color spectrum of topaz and beryl from these pegmatites is amazing.
Lyckberg et al. (2009) noted that gem beryl occurs in only 2% of the approximately 1,900 chamber pegmatites that were mined. Pegmatite 521 at 90 m depth, accessed from shaft 2, produced over two tons of gem beryl. Over one ton was exploited in 1982 and in 1992, over the course of five days, five miners excavated 900 kg in a green clay zone. Ninety percent of these specimens were of gem quality. In the same pegmatite, a second pocket produced 100 tons of quartz in the 1980s. During the spring of 2018, exploration of this pocket yielded a giant quartz crystal measuring 1.5 m in diameter. The pocket was found to also contain topaz pseudomorphs.
In neighboring Russia, gem aquamarine was produced in 2017 at Sherlova Mountain and sold to China, while in the Ural Mountains only small quantities for collectors were found. Here the last Russian underground gem pegmatite mine, the Kazionnitsa, closed in 1993. In the Malkhansk Mountains, tourmaline-rich lithium pegmatites with quality rubellite crystals were recovered during 2012–2018 at the Sosedka pegmatite. They were a deep red to purplish red color in crystals up to 35 cm in matrix, while gem-quality specimens measured up to 10–15 cm. Many of these crystals are reminiscent of the rubellite from the Jonas mine in Brazil, although the cranberry red color is not quite as intense. Several other pegmatite veins started to produce again, primarily green tourmaline.
The Hindu Kush pegmatites of Afghanistan discovered at Kala and Paprok villages in 1959 and 1969 have again yielded large quantities of gem tourmaline in a rainbow of colors. The huge Mawi and Kanakana pegmatites both produced large quantities of gem kunzite, gem indicolite, and rare morganites. Gem-quality pollucite and other rare species such as manganotantalite were found at Paprok and in the Pech Valley. Kanakana and several other pegmatites produced large morganites with aquamarine cores in crystals up to 25 cm in diameter growing on lepidolite and cleavelandite. The pegmatite field of Waygal produced perhaps the finest single 7 kg kunzite crystal of any find, a flawless 55 cm twinned deep purple crystal with blue 10 cm termination in a pocket with 10 kg other gem-quality crystals.

Figure 1. This naturally bicolor topaz, measuring 15 cm across, has eye-visible white fluorite inclusions. It was mined from pegmatite 253 (open pit) in 2017. Photo by Albert Russ, courtesy of Volhyn Kvarts (Quartz) Samotsvety Company.
The Karakorum Mountains of Pakistan have continued to produce large quantities of aquamarine and champagne-colored topaz. Please note that beryl and topaz in these very young 4 to 12 Ma pegmatites have not yet been exposed to radiation from K40 in the feldspars or from U/Th-containing minerals during this short time span. Thus, deeply colored yellow heliodor, blue topaz, and deep orange topaz are not to be expected here, simply because they have not had a chance to attain those colors (Unpublished data by the author, 1997). Those colors are typical for pegmatites one or two magnitudes older.
Gem-quality rare species mined include large colorless to light lilac gem pollucite (10–40 cm), amblygonite, manganotantalite, various microlites, triplite, green hydroxylherderite, beryllonite in cogwheel crystals up to 35 cm, and väyrynenite in orange-red gem crystals up to 22 cm long. The area around Shengus and Bulochi, by the Indus River between Nanga Parbat and Haramosh Peak, is the main producer of the rarer species. Since 1985, known hydrothermal mica-lined fissures at Chumar Bakhoor (Unpublished data by the author, 1988; Lyckberg et al., 2013) have been a major source of matrix aquamarine specimens, large crystals for carvings, and much cabochon and bead material, as well as large pink and green gem-quality fluorite, some of which have been faceted.
REFERENCES
Lyckberg P., Chournousenko V.A., Wilson W.E. (2009) Famous mineral localities: Volodarsk-Volhynsk, Zhitomit Oblast, Ukraine. The Mineralogical Record, Vol. 13, No. 6, pp. 11–22.
Lyckberg P. Chournousenko V., Hmyz A. (2013) Chamber pegmatites of Volodarsk, Ukraine, the Karelia beryl mine, Finland and shallow depth vein pegmatites of the Hindukush-Karakorum mountain ranges. Some observations on formation, inner structures, rare and gem crystals in these oldest and youngest pocket carrying gem pegmatites on Earth. In Contributions to the 6th International Symposium on Granitic Pegmatites, pp. 81–83, http://pegmatology.uno.edu/news_files/PEG2013_Abstract_Volume.pdf
A Multidisciplinary Approach Toward Examining the Sources of Emeralds
Raquel Alonso-Perez1, Adriana Heimann-Rios2, James M.D. Day3, Daniel X. Gray2, Antonio Lanzirotti4, Darby D. Dyar5, and J.C. “Hanco” Zwaan6
1Harvard University, Cambridge, Massachusetts
2East Carolina University, Greenville, North Carolina
3Scripps Institution of Oceanography, La Jolla, California
4The University of Chicago, Argonne, Illinois
5Mount Holyoke College, South Hadley, Massachusetts
6Naturalis Biodiversity Center (National Museum of Natural History), Leiden, The Netherlands
Modern analytical capabilities now allow the combination of nondestructive geochemical and structural studies of emeralds, in addition to detailed studies of their inclusions, to enhance our knowledge of their genesis. Here we present a combination of (1) X-ray absorption near-edge structure (XANES), to determine local coordination environment and oxidation state of the main emerald chromophores Fe, V, and Cr; (2) Raman spectroscopy, with special emphasis on the correlation between H2O molecules and alkali site occupancy; and (3) inductively coupled plasma–mass spectrometry (solution-ICP-MS) to examine the role of major, minor, and trace elements during emerald formation. Our aim is to develop a systematic approach to characterizing emeralds by identifying key geochemical and structural features that enable provenance and geological origin of emerald deposits to be determined.

Figure 1. Multi-incompatible trace element plot normalized to bulk continental crust (Rudnick and Gao, 2004) for emeralds from Colombia, Madagascar, Zambia, Brazil, Egypt, Nigeria, Australia, and Austria, as well as synthetic emeralds.
In this study, we analyzed 31 emeralds from the Mineralogical & Geological Museum, Harvard University. Preliminary XANES results indicate that chromium is present as Cr3+, although crystal orientation dependence and beryl crystal structural behaviors need to be assessed in detail. Raman spectroscopy results of the OH-stretching vibrations at higher frequencies (3500–3700 cm–1), corresponding to H2O type II and type I, respectively, display an orientation dependence. For a given orientation, there is an increase in intensity of the OH-stretching vibration, and therefore H2O concentration, from Colombian to Zambian emeralds. A strong correlation of peak shape and position of the OH-stretching vibration with three major geochemical indices is also observed. Vanadium concentrations correlate positively with Ge, Rb, Cs, and Lu, and they can be used to distinguish three emerald groups based on their geochemistry: (1) Colombia; (2) South Africa, Nigeria, and Egypt; and (3) Brazil, Madagascar, and Zambia. Whereas a smooth transition occurs from group 2 to group 3, group 1 Colombian emeralds are highly distinctive. The distinctiveness of Colombian emerald indicates the potential for using trace-element abundances to examine geological formation (see figure 1). For example, ratios such as Ga/Rb versus Hf/Ta are also characteristic of each different emerald formation. The combination of XANES, Raman spectroscopy, and ICP-MS studies offers significant utility for not only refining the crystal structure of emeralds but also defining markers for different sources.
REFERENCE
Rudnick R.L, Gao S. (2004) Composition of the continental crust. In H.D. Holland and K.K. Turekian, Eds., Treatise on Geochemistry. Vol. 3, The Crust, Elsevier-Pergamon, Oxford, UK, pp. 1–64.
The Proof of Provenance
Klemens Link
Gübelin Gem Lab, Lucerne, Switzerland
Consumers now demand more transparency on the provenance of the goods and services they purchase, an expectation that also applies to luxury products such as gemstones. Yet the gemstone trade has a reputation of being opaque. The Gübelin Gem Lab has kicked off a long-term initiative dedicated to closing this gap. Under the label Provenance Proof, technologies are developed that allow gemstones to be traced back to specific mines in order to provide more transparency throughout the chain of custody. The Provenance Proof initiative is independent of the traditional lab work, and all technologies are made available to the entire industry.
The first technology developed under the Provenance Proof initiative is referred to as the Emerald Paternity Test. The Gübelin Gem Lab has developed a physical tracer using nanolabels to suit the needs of the gemstone industry. These nanolabels are based on DNA fragments encapsulated in silica; with a diameter of 100 nm, they are invisible even to the most powerful optical microscope. The identity of the mine and the miner, the exact location, the time period, and possibly further information are encoded into the DNA. The use of such labels allows the miner to tap the full potential of storytelling about specific provenance, including the possibility of independent proof of this source.
The nanotracers allow the tracing of a gemstone from the end consumer back to the original mine. Nevertheless, the other steps along the value chain remain nontransparent. To shed light on the entire value chain, we developed a digital logbook that allows the user to document all steps and transactions linked to a particular gemstone on its way from the mine to the end consumer. The backbone of this logbook is a hyperledger-based, community-controlled blockchain that is open to the entire industry and accessible with a smartphone. All data is securely encrypted and decentralized and only available to the holder or custodian of a specific gemstone. @topic:2


Publish Year: 2014 Title: Record Prices at Gem Auctions Abstract: ABSTRACT
Auction records kept breaking in late 2014 as the world’s ultra-wealthy buyers vied for rare, important gemstones. At Sotheby’s October 7 Hong Kong auction, an 8.41 ct GIA-graded Fancy Vivid purple-pink, Internally Flawless diamond (figure 1) drew a winning bid of $17,768,041 from a private buyer from Asia. It was the highest price ever paid for a Vivid pink diamond at auction. And at $2.1 million per carat, it came close to besting the all-time per-carat price achieved by a gemstone.

Figure 1. This 8.41 ct pear-shaped Fancy Vivid purple-pink diamond sold for more than $17.7 million at Sotheby’s Oct. 7 auction in Hong Kong. Photo courtesy of Sotheby’s.
On November 21 at Sotheby’s New York, a 9.75 ct Fancy Vivid blue diamond (figure 2) sold for $32,645,000, a new auction record total price for any blue diamond. At $3,348,205 per carat, it was also a new record price per carat for any diamond. The pear-shaped diamond went to a private collector in Hong Kong who named it the Zoe diamond.

Figure 2. This 9.75 ct Fancy Vivid blue diamond sold at Sotheby’s November 21 auction in New York for more than $32.6 million, a record total price for blue diamonds and a record per-carat price for any diamond. Photo courtesy of Sotheby’s. @topic:7


Publish Year: 2015 Title: Gem Artistry in Smaller Sizes Abstract: Sonja Kreis Unique Jewelry

In this video, Alexander Kreis displays his most recent designs: tourmalines in organic fluid shapes resembling the leaves in a tropical forest, citrines evoking the essence of sunrays, and icy blue topaz that mimic the cool brilliance of arctic ice.
At GJX, we caught up with gem artist Alexander Kreis (Sonja Kreis Unique Jewelry, Niederworresbach, Germany). It is a family business, with his father buying the rough, his mother designing the jewelry, and Alexander cutting the gems. Kreis had placed their best Oregon sunstone and their largest rutilated quartz pieces prominently in the booth to achieve a “wow” effect. Immediately beneath those signature pieces, Kreis had positioned more accessible gems that customers could use to make more affordable jewelry items. Although smaller than his trademark pieces, these were invested with the same precision and beauty. He produces pairs that would be ideal for earrings or even men’s cufflinks. Kreis spoke about three of these more accessible lines, involving tourmaline, citrine, and blue topaz.

For Kreis, green and pink tourmaline symbolize the colors of the rainforest, so their design evokes the vivid foliage and blooms of that environment. The curves provide a fluid elegance, and the cuts on the underside capture the veins and structure of tropical leaves.

Among Kreis’s new product designs for this year are citrines cut in a more angular style, with very detailed carvings on the back representing sunrays (figure 1). To Kreis, citrine’s color represents the heat of the sun, while the carvings channel its intense slanted rays.

Figure 1. Gemstone artist Alexander Kreis holds a sun carving, one of his new designs in citrine. Photo by Duncan Pay/GIA; courtesy of Sonja Kreis.
In striking contrast, another new design he called “frozen topaz” (figure 2) uses the icy hue of treated blue topaz to evoke arctic waters. The carving in the center is smoothly polished; the light rays, which are reflected from the polished carving, produce pinpoints of light on the gem’s frosted sides. The design and the material combine to produce an icy brilliance. As the wearer moves the gem, Kreis said, it produces “a harmony of light points dancing through the stone.”

Figure 2. In these examples of “frozen topaz,” the smooth carvings contrast with the frosted textures and lend an icy brilliance to the finished gems. Photo by Duncan Pay/GIA; courtesy of Sonja Kreis. @topic:6