Publication Year: - Title: Amber Care and Cleaning Guide Abstract: The red and green dyes in this bracelet’s amber pieces can fade over time.

Hardness and toughness
Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with which one mineral can be scratched by another. But the Mohs scale is deceptive. The steps between the minerals are not evenly spaced. For example, diamond is only one number away, but it’s many times harder than gems in the corundum family.

Amber is soft compared to gem minerals and many other organics. It falls between 2 and 2.5 on the Mohs scale. Amber also has poor toughness, so care must be taken when wearing amber not to scratch and damage it.

	At Mohs 2 to 2.5, amber is a soft gem and care must be taken not to scratch it.
Stability
Amber burns at relatively low temperatures. With prolonged exposure to light it might darken, and it can be damaged by chemicals.

Cleaning
The only safe way to clean amber is with warm, soapy water. Be sure to use a mild soap.

Treatment and durability considerations
The dyes used to color amber are not stable and can change or fade under certain circumstances. @chapter:37


Publication Year: - Title: De Beers Announces New Deferments; China Devalues Yuan Abstract: The Hong Kong Jewellery & Gem Fair will be an important indicator for business throughout Asia during the next  six months. Photo by Russell Shor/GIA

	De Beers announced that it will allow clients to defer as much as 75% of their Aug. 24-28 sight until as late as March 2016. The move comes after clients left almost two-thirds of their July allocations on the table. De Beers has held the line on rough prices despite a weakening of polished diamonds prices that makes cutting unprofitable.

	The July sight, allocated at about $650 million, totaled between $200 and $250 million after clients deferred or outright refused their goods. De Beers reported that its rough diamond sales fell 21% in the first half of the year and that it would reduce its mining by about three million carats – from a target of 32 million down to 29 million carats – during the remainder of 2015 to deal with the slow market.

	Alrosa, which sells its rough via sights and contracts with consortia in India and Israel, has not significantly lowered prices this year and reportedly has continued to require its clients to honor contracts, leaving some to speculate that dealers are deferring De Beers sights to pay for Alrosa rough.

	Rio Tinto, which has adopted a more flexible pricing policy for its rough, said that revenues fell 23% for the first half of 2015 against the same period last year, while diamond production increased 18%.

	Encouragingly for the diamond industry, Blue Nile’s second quarter 2015 diamond sales increased a reported 6.7% from the corresponding period last year, following a disappointing first half that recorded a 2.1% rise, one of the smallest in the online diamond merchant’s history. Driving the increase was a strong upturn in engagement ring sales – the company’s core strength. Non-engagement and fashion jewelry increased 3.5%. The company is forecasting an increase of 3% to 5% for the year.

	Overall, luxury sales, including jewelry, have languished this year. U.S. jewelry sales continue to run slightly behind last year’s pace; down 1.5% in June. Luxury watch sales declined even more, posting a decline of more than 3%.

	Coinciding with the softening of U.S. retail demand, is a decline in consumer confidence, which fell sharply in July according to the Conference Board, a consumer research organization, as consumers worried that the fallout from the financial bailout for Greece and the declining Chinese economy could affect the U.S. economy.

The slowing Chinese economy and the decline of the renminbi yuan has clouded the outlook for retail jewelry sales in Hong Kong and the mainland. Photo by Russell Shor/GIA

	China, in a move that may deter already slowing diamond sales, devalued its currency, the renminbi yuan, in successive stages by nearly 5% during the week of Aug. 10. Diamonds are traded primarily in U.S. dollars, so the decline in the renminbi will raise prices. The government announced the devaluation to spur demand for Chinese exports as the country’s economy falters. A number of the country’s retail jewelers, however, are already posting sales declines in comparison to last year, so this move will not help.

	The industry will await the results of the Sept. 16-22 Hong Kong Gem and Jewellery Fair, the largest diamond, cultured pearl and gemstone fair in the world. Typically, that fair is the driver for end-of-year business in Asia and its success or failure will be a significant predictor for 2016 business in that part of the world. @chapter:30


Publication Year: 2013 Title: Agates of the Teufelskanzel Near Oberthal, Saarland, Germany Abstract: The “Teufelskanzel” (Devil’s Pulpit), a rhyolitic promontory at Oberthal about 30 km (20 miles) southwest of Idar-Oberstein, is one of the many small agate deposits of the Nahe-Saar Basin. A failed first attempt to mine the agates in 1882 was followed by rather chaotic rockhound activities and the equally unsuccessful decision by the community of Oberthal to take over all mining activities. Finally, digging for agates was generally prohibited, a ban that is still in force.

			The agates generally formed as thunder eggs. They show a very beautiful coloration and often bizarre, picturesque forms that inspire the imagination of the beholder. Many also display a strong green long-wave UV fluorescence, supposedly due to uranyl ions.

			The beauty of the agates and their fluorescence are illustrated by a range of color photos.

Abstracted by Rolf Tatje @chapter:0


Publication Year: - Title: Is Another 1,000 (or 3,000) Carat Diamond Around the Corner? Abstract: Sotheby’s Hong Kong jewelry director Patty Wong holds a 113 ct D color flawless oval diamond that sold for $30 million in a September 2013 auction. Photo by Russell Shor/GIA

	In the fall of 2015, Lucara’s Kerowe mine in Botswana announced the discovery of the first gem-quality diamond larger than 1,000 carats in more than 110 years. Now, Lucara and others have been doubling down on the search for more mega-stones and believe it’s only a matter of months or a few years – not centuries – until another 1,000-carater turns up.

	Why are they optimistic that such a once-in-a-lifetime find could be repeated so quickly?

	Two reasons: economics and technology. Economics created the necessity and technology created the opportunity. Both have made it possible for the number of very large (over 50 carats polished) diamonds entering the market to increase sharply in recent years and open the possibility of new record-breakers.

	Wealthy Buyers Want Large Diamonds

	On the economic side, the 1990s brought an explosion in wealth around the world, particularly in regions with emerging economies including South Asia, Russia and China, while huge gains in financial markets buoyed wealth in Western economies and the Middle East. This fueled an appetite among the global wealthy for the few mega-diamonds that came up for sale each year.

	Until then, large diamonds often met a violent end after they fell into the mining crushers. There’s no way of knowing how many 100-plus, or even 1,000-carat-plus diamonds may have met that fate. That is because the per-carat price differential between large and commercial-sized [under 10 carats] diamonds was not wide enough that it paid for De Beers – then the dominant diamond producer – to retool its diamond recovery processes to save them.

	It sounds incongruous, but through much of the last century, diamond mining profits came from speed – recovering as many diamonds as possible in the shortest time possible. That meant blasting the kimberlite into small pieces, then using giant steel jaws to crush it into even smaller pieces to quickly separate diamonds from waste rock. De Beers’ executives used to acknowledge that any rough diamond larger than 25 carats stood a good chance of being blown up in the blasting process or crushed into small stones before hitting the recovery plants. The ore conveyors were also run very fast to make processing very efficient, but more difficult to catch large stones before they hit the crusher.

The 603 ct. Lesotho Promise is the largest diamond found at the Letseng mine in Lesotho. London jeweler Laurence Graff and the South African diamond cutting firm Safdico purchased the diamond in 2006 and fashioned 26 D color diamonds of various shapes from the rough, including a necklace valued at $60 million. Photo courtesy of Laurence Graff

	One De Beers executive liked to tell the story of how, at the then-partly owned De Beers Diminico mine in Sierra Leone, a worker noticed a flash coming from near the top of the conveyor that fed the crusher. He hit the emergency stop button, just in time to save a 968.9 ct crystal later known as the Star of Sierra Leone. “Another second and…” he said, clapping his hands together imitating the crusher jaws.

	As the 1990s progressed, however, competition – and prices – for the very few 50 carat-plus diamonds that came up for sale began to intensify as wealthy new buyers entered the market, especially at major auction house sales. One of the key price drivers was the emerging wealth in China and Hong Kong, where both Christies’ and Sotheby’s commenced major jewelry sales, with large diamonds as the cornerstone, before the decade’s end.

	These price increases – nearly four-fold between 1995 and 2005 for polished over 10 carats – reset the economic equation for diamond mining.

The rising price of large diamonds, compared to more commercial sizes, made it possible for operations at the Letšeng mineto become profitable. Photo by Russell Shor/GIA

	Case in point. The Letseng mine in the southern African nation of Lesotho, whose signature production is very large diamonds, though at extremely low grade (about one carat of diamonds for every 100 tons of kimberlite, compared to one carat per ton at other mines, one-tenth that of most diamond operations), was reopened in 2004 after 22 years because increasing prices of such stones made the operation profitable.

	The investment has paid off. The mine has been profitable and claims six of the 25 largest diamonds ever discovered: 478, 493, 527, 550, 601 and 603 carats. In addition, Letšeng recovers about 30 diamonds over 60 carats each year.

	New Technology Saves Large Rough Stones

	The change in economics forced a change in the way mining companies process and recover diamonds. This meant introducing new technologies.

	The first technological advance was in the initial crushing. For many decades, big steel jaws were standard equipment at every diamond mine. They were brutal, but effective in reducing large chunks of kimberlite into manageable smaller pieces. As the new millennium proceeded, miners introduced “kinder, gentler” methods known as “autogenous,” which tumbles or grinds the kimberlite pieces against one another without the intense pressure generated by crushing.

	Such autogenous processes take several forms. Some employ a rotating/oscillating cone in the ore intake chamber that propels the kimberlite pieces into one another and against the sides of the receptacle. After Letšeng employed this system, recovery of 100 carat-plus diamonds more than doubled. Other processes employ large rotating mills that grind the kimberlite pieces against one another.  For more details refer to Letšeng’s Unique Diamond Proposition in the fall 2015 issue of Gems & Gemology.

This is the exterior of the cone oscillator in the processing plant of the Letšeng Mine in Lesotho. The cone method propels the kimberlite pieces into one another and against the sides of the receptacle to reduce the potential for breaking large diamonds. Photo by Russell Shor/GIA

	The second component of new recovery technology is the use of X-ray processing, which replaced or complemented the century-old grease belt system. Diamonds would adhere to grease-coated conveyors and waste rock fell off the sides. The method was fairly effective, but De Beers and others have made a lucrative sideline of re-mining old tailings for diamonds that were overlooked the first time.

	X-ray processing has greatly improved the recovery rate and spared large stones by identifying them before they hit the crushers. XRL (X-ray luminescence) and XRF (X-ray fluorescence) units developed in the 1980s take advantage of the fact that diamonds will fluoresce when exposed to intense X-rays. The crushed kimberlite particles are dropped in a thin stream under a beam of X-rays. When a diamond fluoresces, it activates a photo-detector, triggering a jet of air that deflects the diamond into a collector box.

	Older X-ray recovery units identified diamonds by fluorescence alone, causing non-fluorescent diamonds (which include many large type II stones) and some fancy-color diamonds to slip through to the waste piles. More recent methods adopted at Letšeng and others employ X-ray transmissive (XRT) technology to identify large rough type II crystals trapped in kimberlite and eject them from further processing. The general principle behind XRT sorting is that diamond shows up as a much brighter image than other material; it does not rely upon a diamond’s transparency because it does not deal with visible light range. Even if the sample is sufficiently coated to be completely opaque, the XRT sorter is designed to detect it. It was such a unit that found the 1,109 ct Lesedi la Rona diamond.

	This new technology has enabled smaller mining companies, such as Gem Diamonds, operator of Letšeng, Lucara Diamond Corp. of Vancouver and Lucapa Diamond Co. of Perth, Australia, to recover massive diamonds that, until this decade, had been once-in-a-decade occurrences.

	In addition to the Letšeng, Lucara’s Kerowe mine in Botswana yielded the 1,109 ct Lesedi la Rona diamond, the second largest gem-quality diamond ever found, and an 813 ct diamond and 47 others over 100 carats. Lucapa, which operates the Lulo project in Angola, discovered a 404 ct diamond in February 2016.

The 1,109 ct Lesedi la Rona diamond was the first gem quality rough over 1000 carats found in more than a century.  Mining executives are certain there are others of that size − or larger − awaiting discovery. Photo courtesy of Lucara Diamond Corp.

	Room for Improvement

	The mining companies acknowledge that they still have a way to go. Lucara executives believe a 374 ct diamond found a few days after the Lesedi la Rona diamond had been part of that stone before blasting.

	The largest diamond ever found was the 3,106.75 ct Cullinan from South Africa’s Premier mine two years after it opened in 1903. (That diamond originally weighed an estimated 8,000 carats but was broken by natural forces or blasting.) Premier (now named Cullinan) has been the world’s most prolific treasure house, yielding more than 750 diamonds weighing over 100 carats in its 113-year history.

	After De Beers sold the mine in 2007, the new owners, Petra Diamonds, have been investing in new recovery technology designed to recover diamonds even larger than 3,000 carats.

	The executives of Lucapa and Lucara say they, too, are vying to beat that record. @chapter:38


Publication Year: - Title: Changes Coming for De Beers’ Sights Abstract: These diamonds – 22.32 ct macle, left, and 1.01 ct round brilliant – are from the Oppenheimer Collection. Gift of DeBeers, photo by Robert Weldon/GIA

	This week’s De Beers’ sight is unlikely to feature significant price increases, but company executives are laying out a series of major changes in the sight system that will begin in January.

	First, De Beers will tighten the credit reporting requirements for each client. The company has reportedly backed away from a more strict policy proposed by major industry banks that would sharply reduce a client’s acceptable debt-to-equity ratio. Many major clients, however, continue to struggle with high debts and slow collections and would be unable to meet those more stringent requirements.

	Earlier this year, the banks financing the diamond industry sharply reduced their credit exposure. They began to require that sightholders and other rough dealers fund a minimum of 30% of their purchases themselves, instead of the banks providing 100% funding.  In addition, they trimmed their lending ratio to as little as 60% of receivables.

	Second, the company reportedly introduced new client selection criteria for existing sightholders based, in part, on previous buying. During the past several years, clients have been refusing some rough diamond assortments they believe are too expensive for the market. Some also deferred purchases in hopes that De Beers would lower prices on those goods in future sights.

	De Beers also is reportedly introducing a new class of client, an Accredited Buyer, who will be able to purchase rough that is not contracted to existing clients. It is likely that most of the Accredited Buyers will be selected from buyers who participate in De Beers’ rough diamond auctions. The company already has appointed three sightholders from its auction buyer list.

SYNTHETICS: Concern over the infiltration of undisclosed synthetics into the diamond pipeline has prompted the Indian government, at the urging of the leading Indian industry organization, to propose a 10% import duty on synthetic polished diamonds.

	All, or nearly all, synthetic diamonds are manufactured outside of India. The Gem and Jewellery Export Promotion Council in India is pushing the extra duty to reduce the price differential between natural and synthetic diamonds, it said in a statement. The government is also considering a 5% duty on synthetic rough diamond imports.

	Although concern over the advent of synthetics is rising following several reported discoveries of undisclosed stones mixed in parcels of naturals, GIA remains confident it can differentiate all lab-grown diamonds from natural stones. In addition, GIA and other firms have developed detection equipment to screen parcels of diamonds that are generally too small to be sent to gemological labs for grading. @chapter:30


Publication Year: 2019 Title: Intergrown Emerald Specimen from Chivor Abstract: Figure 1. An emerald crystal inclusion measuring ~2.67 × 2.71 × 5.43 mm is found inside this large emerald specimen (18.35 × 10.69 × 9.79 mm) from Colombia’s Chivor mine. Photo by John Jairo Zamora.

Colombia’s Chivor emerald mines are located in the eastern zone of the Eastern Cordillera range of the Andes Mountains. Chivor translates to “green and rich land” in Chibcha, the language of the indigenous people who were already mining emerald more than 500 years ago, before the arrival of the Spanish conquistadors (D. Fortaleché et al., “The Colombian emerald industry: Winds of change,” Fall 2017 G&G, pp. 332–358). Chivor emeralds exhibit a bright green color with a tint of blue; they have relatively high clarity and fewer inclusions than emeralds found in Colombia’s western belt.
The authors recently examined a rough emerald crystal specimen (figure 1), measuring 18.35 × 10.69 × 9.79 mm, reportedly from Chivor. This crystal weighed 3.22 g (16.10 ct) and had a prismatic hexagonal crystal shape. Standard gemological examination confirmed the gemstone to be emerald, and ultraviolet/visible/near-infrared (UV-Vis-NIR) spectroscopy showed a classic Colombian emerald absorption spectrum. The crystal’s color was typical of Chivor emeralds, a medium dark green showing a blue tint. The emerald, which hosted jagged three-phase inclusions that are typically observed in Colombian material, showed no signs of clarity enhancement.

Figure 2. Left: A well-formed emerald inclusion, showing a hexagonal prismatic shape with pyramidal termination. Right: The view from below shows a perfect hexagonal crystal outline. Photomicrographs by John Jairo Zamora; field of view 12 mm.
The emerald specimen hosted a large, unique inclusion of emerald almost perpendicular to the c-axis, measuring approximately 2.67 × 2.71 × 5.43 mm. The inclusion’s identity was confirmed by Raman spectroscopy. The inclusion exhibited a well-formed hexagonal prismatic shape with pyramid-like termination (figure 2). Although intergrowth emerald crystals have been described and documented in the literature several times (G. Grundmann and G. Giuliani, “Emeralds of the world,” in G. Giuliani et al., Eds., Emeralds of the World, extraLapis English, No. 2, 2002, pp. 24–35; I. Sunagawa, Crystals: Growth, Morphology and Perfection, Cambridge University Press, 2005, pp. 127–149), it is always a spectacular feature to observe, making this emerald rough crystal from Chivor with an emerald crystal inclusion a unique collector’s specimen. @chapter:8


Publication Year: 2024 Title: Gold Granulation by Zaffiro Abstract: Figure 1. Elizabeth and Jack Gualtieri of Zaffiro at their AGTA booth. Photo by Jennifer Stone-Sundberg.
Granulation, an ancient goldsmithing technique dating back nearly five millennia to Mesopotamia, involves the joining of tiny high-karat gold or other precious metal spheres (“granules”) to a metal base to create a decorative pattern (J. Wolters, “The ancient craft of granulation,” Gold Bulletin, Vol. 14, No. 3, 1981, pp. 119–129). These patterns can be very complex, and the granulation process is one that requires a high level of precision.
In the AGTA designer showroom, we spoke with Jack and Elizabeth Gualtieri of Zaffiro (Walla Walla, Washington; figure 1), who specialize in 22K gold granulation. They occasionally incorporate platinum as well. They find the granulation technique very rewarding and meditative, as it demands extraordinary focus.
The Gualtieris formed Zaffiro in 1996 in Portland, Oregon, after meeting at the University of Kansas several years earlier. Their focus on granulation was inspired by a seminar at the university and by Elizabeth’s study abroad in Florence. They chose the name “Zaffiro,” which translates to sapphire in Italian. The business was a part-time venture until they could dedicate themselves to it full-time starting in 2003. They have sold their pieces through galleries, retail shows, and private clients. In 2019, they moved to Walla Walla.
Jack and Elizabeth design and construct each piece from start to finish and consult with each other on their individual designs. They alloy their own 22K yellow, white, and rose gold and also create their own gold sheet, wire, and granulation balls. After clipping snippets of wire onto charcoal blocks, the blocks are heated to bead the metal into tiny balls of gold, which are then sorted by size through sieving. (See video below showing the process of making granulation balls).

	Granulation Process

The Gualtieris find inspiration in the stones they purchase, the natural world around them, and architecture. In fact, they sometimes have to negotiate over who will get to use a particular stone, as both artists may simultaneously envision designs for it.

Figure 2. “Where the Ocean Meets the Sky” is a one-of-a-kind pendant featuring a 19.51 ct Australian boulder opal and 11.37 carats of blue moonstone. The boulder opal is accented with 0.63 carats of tsavorite garnet. The granulated yellow gold is 22K, and the gold links between the elements are 18K yellow gold. Photo by Robert Weldon; courtesy of Zaffiro.
Jack’s opal, moonstone, and tsavorite garnet pendant design (figure 2) began with the Australian boulder opal. The moonstones inspired him to go larger with the design and add some movement to the piece. He said the use of green tsavorite garnet accent stones around the opal instead of blue stones was a riskier option but ultimately the right choice.

Figure 3. Tanzanite pendant designed and fabricated by Elizabeth Gualtieri containing a 46.15 ct tanzanite crystal in a hand-fabricated setting of granulated 22K gold. Photo by Robert Weldon; courtesy of Zaffiro Jewelry.
A heated rough tanzanite crystal inspired the pendant designed and built by Elizabeth in figure 3. This piece represents a signature style the Gualtieris describe as “talismans,” signifying the way in which collectors of the pieces connect with them. This jewelry collection features rough crystals or baroque pearls and represents some of Zaffiro’s most personal pieces. The intricate caps allow for a more expressive use of granulation and accent stones.
The fusion of this ancient technique with contemporary jewelry designs is a testament to the timelessness of granulation and its endless design possibilities. @chapter:21


Publication Year: 2015 Title: Rare “Star and Cross” Quartz from Brazil Abstract: Figure 1. Face-up view of two quartz cabochons from Brazil, weighing 116.95 ct (left) and 44.12 ct (right) with cross-like quartz inclusions. Photo by Jaroslav Hyršl.

	The author purchased two very unusual quartz samples (figure 1) in Brazil in 2015. Both were cut as cabochons with a slightly curved bottom; one weighed 116.95 ct (35.0 × 30.3 × 15.6 mm), while the other weighed 44.12 ct (28.3 × 22.3 × 10.0 mm). The larger cabochon was slightly milky, while the smaller one was almost clear. Both showed a strong six-rayed star when illuminated (figure 2). The stars were centered on the top of the cabochons, which indicates that both were cut perpendicular to the c-axis. The most unusual feature was a cross-like inclusion in both stones. It was white and coarse-grained, only slightly translucent. The longer part of both crosses measured about 4 mm wide. The shorter part had a thickness 1.5 to 2 mm and the angle of the intersection was about 85 degrees in both cabochons, which meant that the two specimens were probably cut from the same crystal. Refractive index results and Raman analysis showed the cross to be quartz, rather than a foreign mineral. The origin of the cross inclusions is uncertain, but they are strong evidence of nature’s ability to produce rarities.

Figure 2. The stars in the quartz samples, seen from the base, are eye-visible in sunlight. Photo by Jaroslav Hyršl. @chapter:13


Publication Year: 2013 Title: Optical Defects in Diamond: A Quick Reference Chart Abstract: ABSTRACT
Gem diamonds owe much of their value to their color, or lack thereof. Defects in the atomic structure of diamond are responsible for this color and are important for the identification of color treatments. This article and its tables are intended as a quick reference for gemologists as they read about various common diamond defects in the gemological literature.
INTRODUCTION
Despite the commercial value of natural-color diamonds, distinguishing them from treated diamonds remains a significant identification challenge. While some diagnostic visual features exist (inclusions, color or growth zoning, and absorption bands seen with a spectroscope), the separation of natural from synthetic or treated diamonds is not always possible using standard gemological methods. In such cases, advanced spectroscopic analysis at a professional gem-testing laboratory is required. Imaging of luminescence distribution patterns is also a helpful tool for recognizing synthetic diamonds (Martineau et al., 2004; Shigley et al., 2004).

In a laboratory setting, the identification of diamonds is based mainly on the detection of tiny imperfections in the atomic lattice. These “defect centers” may include foreign impurity atoms (typically nitrogen, and occasionally boron or hydrogen); carbon atom vacancies in the lattice (either single or clusters of neighboring vacancies); carbon atoms positioned in between normal lattice locations (interstitials); and dislocations where planes of carbon atoms are offset from one another due to plastic deformation. Not all of these lattice imperfections create spectroscopic features, but several do so by allowing the diamond to absorb particular energies of incident light or radiation. Defects can occur randomly or in particular locations within the lattice. Diamonds can contain more than one type of defect, and in natural diamonds, defects can be altered over geologic time in the earth or by exposure to heat or radiation during color treatment.

So-called optical defects (or optical centers) cause absorption in the visible or near-visible portions of the electromagnetic spectrum, often producing coloration (e.g., figure 1). Luminescence reactions result when defects absorb higher-energy incident radiation and then reemit lower-energy radiation as visible light. Optical defects occur in very low concentrations in all diamonds, and their presence can be detected using spectroscopic techniques. A theoretically “pure and perfect” diamond containing no such defects would appear colorless.

Figure 1. The red color of the graining in this Fancy red diamond from Brazil is caused by absorption related to the 550 nm band. This band, the most common cause of pink to red color in natural, untreated diamonds, is thought to be the result of a defect created by plastic deformation. Photomicrograph by Jian Xin (Jae) Liao; magnified 50×.
As a quick reference for gemologists, table 1 lists the most common lattice defects, including those that can create color and/or luminescence reactions in diamond. The scientific name of the defect, as well as the wavelength (or wavenumber) and electron volt (eV) positions of the main and associated spectral bands, are shown along with photos of representative diamonds. The most common spectroscopic technique used to detect the defect center is indicated by a code shown in italics.

Download a Larger Version of this Optical Defects Chart

Table 1. Important optical defects in diamond and their effect on color and luminescence.
Some precautions should be kept in mind when using this table. Each lattice defect is known to produce a particular diamond color or luminescence. For instance, the GR1 center produces green or blue-green color. But the reverse is not necessarily true—for example, not all green diamonds owe their color to the GR1 center. In fact, there are several causes of green color. In some cases, a diamond contains more than one optical defect, and its color stems from a combination of defects. In other cases, a diamond’s color may arise from absorption caused by one optical center, while its luminescence may result from another optical center.

Table 2 provides a comparison of the most common spectroscopic techniques for diamond characterization. For further reading on color in diamond, the Additional Reading list serves as a reference guide to access the much larger range of gemological and technical literature on diamond identification. @chapter:11


Publication Year: 2016 Title: Emerald/Emerald Doublet Abstract: Figure 1. This 1.81 ct specimen was a natural emerald/emerald doublet. Photo by Claire Ito; field of view 10.5 mm.

	While various combinations of materials are used to form doublet gems, we seldom see doublets consisting of the same materials. Ruby/ruby doublets (Spring 1987 Lab Notes, pp. 47–48; Spring 1996 Lab Notes, p. 49) as well as a tourmaline/tourmaline doublet (Summer 1990 GNI, pp. 165–166) have been reported, but a doublet consisting of two sections of natural emerald has not been previously documented.

	GIA’s Tokyo laboratory recently examined a 1.81 ct transparent green octagonal step cut that measured approximately 7.22 × 6.71 × 5.55 mm (figure 1). Standard gemological testing indicated an SG of 2.71, with an RI of 1.572–1.580 on the crown and 1.570–1.578 on the pavilion. A chromium spectrum consistent with emerald was visible with a handheld spectroscope. Upon first glance, this stone appeared to be a natural Colombian emerald, but careful examination easily revealed its doublet nature, while Raman spectroscopy confirmed that both the top and bottom portions were indeed beryl.

	Microscopic observation revealed a very flat separation plane below the girdle, crossing the pavilion diagonally. Flattened gas bubbles were visible along the plane (figure 2, left), and a blue and orange flash effect was also apparent. Jagged three-phase inclusions typical of Colombian emeralds were visible in both parts, while fine growth tubes and fingerprints in helix patterns were seen only in the top portion. Inclusions did not cross the boundary between the two sections. Under long-wave UV light, the top showed a stronger red fluorescence than the bottom, with a distinct boundary between the two (figure 2, right). A whitish fluorescence was also observed along the plane. Illumination using crossed polarizers revealed that the top and bottom portions had different optical orientations, with two optic axes visible (figure 3). Typical of most emeralds, enhanced fractures showing a flash effect were found in both parts.

Figure 2. Left: Flattened gas bubbles are visible along the separation plane of the doublet. Field of view approximately 3 mm. Right: Viewed under long-wave UV light, the doublet displayed strong red fluorescence in the top portion but not the bottom. A distinct boundary between the two parts is clearly visible. Photos by Ahmadjan Abduriyim.

Figure 3. When the doublet was viewed under crossed polarizers, different optical orientations were apparent. At this angle, interference colors along the optic axis are clearly visible in the bottom portion but not the top. Photo by Claire Ito; field of view 11.60 mm.

	Immersion with methylene iodide revealed green angular zoning in the bottom, whereas the top had even, saturated green color. Both sections appeared to have enough green color to be considered emerald. The glue along the separation plane was colorless. This is unusual, as assembled imitations of emerald are often composed of pale beryl or other colorless materials with a green cement layer. We could only speculate on the circumstances leading to the creation of this unusual doublet. @chapter:9


Publication Year: - Title: Petra Unveils Super Blue; De Beers Holds Prices on Rough Abstract: Petra Diamonds CEO Johan Dippenaar holds the 122.52 carat blue diamond recovered in June 2014 from the historic Cullinan Mine in South Africa. Photo courtesy Petra Diamonds

	One of the largest blue diamonds ever found ‒ weighing in at 122.53 carats (cts.) ‒ was unveiled this week by Petra Diamonds, owner of the historic Cullinan Mine in South Africa, a 111-year-old mine that has produced some of the most famous diamonds in history.

	Petra said the stone would be sold after it has “analyzed the diamond to assess its potential value…and… its optimal route to market.”

	The Cullinan, opened in 1903, produced the largest diamond ever found, the 3,106 ct. Cullinan diamond, which was cut into the 550 ct. Cullinan I that remains the centerpiece of the British Crown jewels. The mine has produced more than 750 diamonds larger than 100 cts. and a number of renowned fancy colored diamonds, including the Heart of Eternity, a 27 ct. Fancy Vivid blue that was part of De Beers’ Millennial collection. Petra acquired the Cullinan Mine from De Beers in 2008.

ROUGH PRICES: De Beers held the line on prices at the June 10-13 sight, which totaled about $650 million. The sight was slightly larger than expected because rough demand has been rising, including for more goods that will polish out to lower quality stones. (See Las Vegas show report below).

	Dealers report that premiums for De Beers goods in the rough after-market was a healthy 5-8%, which is enough to make a profit, but did not reach the inflated, speculative levels of last year. Dealers believe this was a good sign that the banks’ tighter credit policies are finally curbing speculative rough buying.

	Alrosa, the marketing agency for Russia’s diamond production, raised prices of its rough diamonds 2-3% during its sale the same week. Reports from tender sales also indicate that buyers were purchasing rough for their manufacturing needs and not speculation, which has resulted in prices much closer to the market.

JCK, LAS VEGAS: Demand generally met expectations, but retailers were extremely cautious, buying only for immediate inventory needs and resisting price increases.

	Dealers say polished prices had been edging up this year, particularly during the run-up to the show, but retailers were in no mood to accept the increases – particularly after the statement from Blue Nile’s CEO that consumers have been declining to pay higher prices for diamonds.

	Diamond buyers for a number of mall jewelers were trying to maintain price points for middle class consumers and were down-trading into I1 and I2 clarities and “light” sizes (just under 0.50 ct. or 1 ct.) as diamond manufacturers try to pass rough price increases on to them. In China, which once had insisted on high clarity goods, demand is centered on SI goods in middle colors.

	“Demand is there,” said one dealer. “But the battles over prices are worse than they’ve ever been and a lot of deals are not being made – at least now.”

	Another reason why a number of deals did not get done at the show is that tightening bank credit policies are forcing some diamond and jewelry firms to drastically reduce the memo programs they run with large retailers. These deals usually involve consigning a certain percentage of the order with payments due as long as 90 days after Christmas, with an additional return allowance. Most jewelry manufacturers also operate similar memo programs for their large retail customers.

	Banks financing the diamond industry introduced a number of stringent rules this spring, including a substantial reduction in credit that supports such memo programs.

	Diamond people were reluctant to discuss this issue in detail, but the few who did, say they were forced to cancel or severely curtail some orders because the banks would not supply the funds. Dealers admitted it was a problem, but said they could adjust to it as long as retailers get the message as well.

	Colored gemstone demand at the American Gem Trade Association hall was spotty, with some of the larger firms reporting respectable business (mostly from repeat customers), while many other exhibitors found demand slow.

	One of the problems dealers face is the ever-increasing price of gemstones, especially higher quality material, which seems to climb regardless of demand.

	Sellers of Mozambique ruby were waiting for the first Gemfields auction of that material in June to gauge prices, which until now had varied widely from vendor to vendor. Gemfields acquired the rights to several large mining concessions within that ruby- producing area.

	“We suspect they will be much higher than (most dealers) are selling these goods for,” said one dealer with a large stock of them. “Everybody is waiting to see how things go.”

	Several dealers were displaying Yogo (Montana) sapphires for the first time in several years. The stones are generally small (under 1 ct.), but a significant percentage do not require heat or other treatments.

	Demand at the Couture and Luxury shows, which attracts retailers serving the higher end of the market, reported much stronger results, reflecting the uneven economic recovery. Demand for 3-carat-plus colorless diamonds and fancy colored diamonds was much stronger than last year.

	Designers featured multi-color pieces and Art Nouveau elements in their offerings. @chapter:38


Publication Year: 2016 Title: Book Review: Wartski: The First Hundred and Fifty Years Abstract: By Geoffrey Munn, hardcover, 288 pp., illus., publ. by Antique Collectors’ Club Ltd., Woodbridge, Suffolk, UK, 2015, US$125.00.

	Family-owned businesses are the backbone of the gem and jewelry industry. This is true for both small-scale companies and internationally known brands. One British-based family firm founded in the nineteenth century is the focus of Wartski: The First Hundred and Fifty Years, a commemoration of the company’s landmark anniversary. Since 1865, Wartski has specialized in Russian royal court art, fine jewelry, and silversmithing, building a world-class clientele (including the British royal family and numerous celebrities) along the way. Built on the efforts and dedication of the four generations from two families and its passionate employees, Wartski is still very active in the fine jewelry trade.

	Author Geoffrey Munn has worked for Wartski for over 40 years, since the age of 19. Today, he is the company’s managing director and official historian, a certified antiques expert, a BBC television show presenter, and a successful writer, as well as a renowned expert on Faberge metalwork and jewelry. A great storyteller, Munn brilliantly connects the most spectacular artworks with the human story of this unique business on each page of this book.  While readers will be immediately attracted by the exquisite photos and illustrations (particularly of the fine metalwork, jewelry, and celebrity patrons), Munn emphasizes at the start that this is a book to elaborate on the history of the business rather than the amazing artworks it collected and sold.

	The preface and the first two chapters are riveting, digging deep into the origins, growth, and all the challenges and successes of Wartski. The story of how founder Morris Wartski, the great-grandfather of the current business owner, had a life changing opportunity and opened the family’s first ever business in Bangor, North Wales reads like a movie script. Through hard work, integrity, expertise, and outstanding salesmanship, they successfully conquered all the difficulties met in the past century and half. Present jewelry businesses may have different challenges to face, but how this firm survived some of the critical periods in history might shed light on today’s practices. For instance, during the 1950s auction houses such as Sotheby’s and Christie’s stepped into the jewelry business, and Wartski felt the pressure of their presence. By sticking to their specialties like the Russian Fabergé eggs, jewelry and other art pieces, Wartski further strengthened its expertise on special collections and not only survived , but thrived.

	Wartski first gained attention from the British royal family due to their spectacular collection of Russian royal court jewels and artwork, especially those made by Carl Fabergé, including the 13 famous imperial Fabergé eggs. The second generation of Wartski jewelers were among the first to purchase these treasures from aristocrats after the Russian Revolution and from the Soviet government when it needed money to facilitate the new country. These painstaking purchases built a solid base for this brand, and attracted the British royal family members, whom Wartski has served as jewelers ever since. Today, Wartski has a royal appointment as jeweler to both Queen Elizabeth II and the Prince of Wales.

	The following chapters elaborate upon the diligent work done by the family to collect the world’s finest jewelry and metalwork (such as the Egyptian crown jewels) and the clients who visited and supported Wartski over the years, including former first lady Jacqueline Kennedy Onassis, author Ian Fleming, and the current Duke and Duchess of Cambridge The important clients of Wartski will attract a lot of readers even they are not in the industry. The enthusiasm of collecting and the future of the business are also explored.  All content was extremely well illustrated with eye-catching photos of well-known jewelry and precious metalwork, along with images of pieces never seen before.

	Though Munn has chosen to focus on the company’s history, one intriguing story involving a specific piece focuses on the lost imperial Fabergé Easter egg. Named “Nécessaire,” the egg was commissioned by Alexander III of Russia in 1889. It was set with diamonds, ruby cabochons, emeralds, a large colored diamond, and a sapphire cabochon, and the interior showed a little box mounted with 13 diamonds. The last showing of this piece occurred at Wartski in June of 1952. An anonymous buyer purchased it from the store; since then, the whereabouts of this treasure are lost. Munn’s exploration of Nécessaire’s whereabouts, based on a black and white photo taken during its last show at Wartski, will be fascinating to many readers.

	What distinguishes this book from most others is the depth of the knowledge and the insights Munn delivered to the readers. His fantastic storytelling skill adds charm to this book and made it an enjoyable experience for jewelry professional and enthusiasts alike. Readers get to know behind-the-scene stories and appreciate the diligent work jewelers and collectors do before they present these breathtaking pieces of art to the public.

	Overall, Wartski: The First Hundred and Fifty Years is fascinating in many different ways; it is well worth reading and will be a great addition to any jewelry book collection. @chapter:21


Publication Year: - Title: GIA Diamond Grading Report Provides Most Respected Diamond Analysis Abstract: Items of significant value typically come with important documentation. Houses have deeds. Vehicles have titles and registration. Purebred pets have pedigree papers. And a college education is validated with a diploma. But what about something as valuable as a diamond? The answer is yes: independent support documentation is available for diamonds to verify their quality and provide positive identification.

The most widely used and recognized means of verifying a diamond’s quality is with a GIA Diamond Grading Report™, provided by the internationally recognized, nonprofit GIA (Gemological Institute of America).

A report from GIA provides an expert analysis of the quality of a diamond based on the 4Cs of diamond grading: color, cut, clarity and carat weight. The GIA Diamond Grading Report also includes a plotting diagram that depicts the diamond’s unique clarity characteristics, such as inclusions. In addition, since GIA is not affiliated with any commercial enterprise, the public is assured the world’s most impartial and accurate analysis of a diamond.

The GIA laboratory employs highly trained diamond graders, gemologists, and research technicians and scientists to ensure the highest caliber of analysis for every diamond submitted for grading. Some of the world’s most famous diamonds have been graded by GIA laboratory experts, including the legendary Hope Diamond (45.52 carats), the De Beers Centenary Diamond (273.85 carats) and the Taylor-Burton Diamond (69.42 carats).

GIA only grades unmounted diamonds, and the fee for services varies based on the weight of the diamond. For an additional fee, the unique GIA Report Registry number can be micro-laser inscribed onto the diamond’s girdle (thin outer edge). This unique number provides added security to the diamond’s owner. The owner can also choose to inscribe a personal message, such as “I Love You” or a special date. The number or wording is permanently registered in GIA’s archive database.

Diamonds weighing 1.99 carats or less can be issued a GIA Diamond Dossier®. This report provides the same information as the GIA Diamond Grading Report, except for the plotting diagram. The micro-laser inscription of the diamond’s unique GIA Report number is included for each diamond receiving a Dossier at no additional charge.

The most convenient way for the public to obtain a GIA Diamond Grading Report or Diamond Dossier, or to request laser inscription services from the GIA laboratory, is to request services through a local fine jewelry retailer. Retail jewelers are familiar with the care and handling of diamonds and jewelry, are better equipped to facilitate service arrangements, and are uniquely qualified to advise the public on the importance of features discussed in a GIA Grading Report.

In 2012, GIA announced the GIA Diamond eReport service, delivering GIA grading results completely online. It is available for natural, D-to-Z color diamonds from 0.15 to 2.99 carats and is available via Report Check, GIA’s secure web-based report database. This new digital-only report provides grading results in a format that is not only more environmentally responsible, but also meets the needs of an evolving marketplace where information must be accessed and communicated rapidly. Additionally, the paperless report format allows us to offer this grading service at a lower fee.

GIA, the world’s foremost authority in gemology, is a public benefit institute and was established in 1931.  The organization is noted for such achievements as inventing the modern jeweler’s loupe (1934), creating the 4Cs (late 1930s), and establishing the International Diamond Grading System™ (1953) – which is recognized worldwide as the standard for diamond grading. @chapter:31


Publication Year: - Title: Conference Report: 21st General Meeting of the IMA Abstract: Dr. Gaston Giuliani presented on the oxygen isotope and trace-element chemistry of corundum at the General Meeting of the IMA in Johannesburg. Photo by Robert Weldon/GIA.

                      The 21st General Meeting of the International Mineralogical Association (IMA) was held September 1–5 in Johannesburg, South Africa. Several oral and poster presentations were presented in a session on gem materials.

G. Agnosi (University of Bari, Italy) discussed preliminary results of an X-ray diffraction topography study of Colombian trapiche emeralds, which revealed a consistent crystallinity between the arms and the hexagonal core. She presented a model of trapiche formation in which the growth of the hexagonal core occurred first, followed by the six arm sections. Ulrika D’Haenens-Johansson (GIA, New York) outlined the status of synthetic diamond production. She reviewed the means of identification based on visual observations, structure-related ultraviolet fluorescence reactions, and distinctive spectroscopic features. In concluding, she noted that synthetic diamonds can be unequivocally recognized by major gem laboratories.

Andrew Fagan (University of British Columbia, Vancouver) presented the geologic setting and a model of formation of the Fiskenaesset corundum district in southwest Greenland. Estimates of ore reserves suggest that this could become a commercial ruby deposit. Gaston Giuliani (Centre de Recherches Pétrographiques et Géochimiques, Nancy, France) studied the oxygen isotope and trace-element chemistry of sapphire xenocrysts in basalts from Changle, China, and of corundum from the Mbuyi-Mayi kimberlite in the Democratic Republic of Congo, to trace their primary sources. In both cases, the host basalt and kimberlite transported the corundum crystals from the lower crust and upper mantle.

Daniel Ichang'i (University of Nairobi) described efforts by the Kenyan government to document and better understand the geologic setting of the country’s numerous gem deposits. He discussed two main occurrence lithologies: the metamorphic rocks of the Neoproterozoic Mozambique Orogenic belt, and the Paleogene-Neogene basaltic volcanics in the Northern and Central Kenya Rift regions.

Stefanos Karampelas (Gübelin Gem Lab, Lucerne, Switzerland) detailed the gemological characteristics of emeralds from Itatitia in Minas Gerais, Brazil. The emeralds formed along the contact between phlogopite schists and highly evolved granitic pegmatites. Based on minor and trace-element chemistry, they can be distinguished from emeralds from other Brazilian and world deposits. Vincent Pardieu (GIA, Bangkok) gave a talk about Montepuez in northern Mozambique, which is currently the world's largest source of high-quality rubies. He also presented a short movie about GIA expeditions he has led to gem deposits in eastern Africa. Wuyi Wang (GIA, New York) presented a study of carbon isotopes of synthetic and natural diamonds. The latter displayed δ13C values from 0 to -20‰, while the former ranged from -25 to -75‰.

Dr. Wuyi Wang provided a look at the carbon isotopes of natural and synthetic diamonds. Photo by Robert Weldon/GIA.
Christopher M. Breeding (GIA, Carlsbad, California) described the interesting features of alluvial diamonds from the Marange deposit in eastern Zimbabwe. These type Ia diamonds display surface radiation staining, aggregated nitrogen impurities, and elevated hydrogen impurity contents, but these features do not provide a reliable indicator of geographic origin. Julien Feneyrol (Centre de Recherches Pétrographiques et Géochimiques, Nancy) presented a model of the metamorphic formation of tsavorite nodules in primary deposits. The tsavorite nodules are always contained within graphitic gneiss and calc-silicates with intercalations of marble. Elena Sorokina (Fersman Mineralogical Museum, Moscow) described a model of ruby and sapphire formation in marbles at Snezhnoe in Tajikistan. @chapter:23


Publication Year: 1995 Title: Spring 1995 G&G Book Reviews Abstract: “Gems, their Sources, Descriptions and Identification, 5th Edition”
By Robert Webster Rev. by Peter Read, 1,026pp., illus., Butterworth-Heinemann, Oxford, England, 1994. US$120.00

“Hey's Mineral Index, 3rd Ed.”
By A. M. Clark, 852 pp., Chapman & Hall, London, 1993, US$79.95

To view the full section, download the PDF above. @chapter:1


Publication Year: - Title: GIA Lab Reports on Low-Temperature Heat Treatment of Mozambique Ruby Abstract: Drawing on extensive experience with traditional and modern methods, many Sri Lankan “burners” have become adept at low-temperature heat treatment of ruby from Mozambique. Photo by Vincent Pardieu/GIA.

                      Since 2009, Mozambique has become the world’s leading source of commercial and gem-quality ruby. While many gems from this country are subject to “conventional” high-temperature heating (1300oC, or 2,372oF), rumors have been circulating within the gem trade that many rubies might be treated in Sri Lanka at much lower temperatures. With red to pink corundum, low-temperature treatment aims to remove any blue color component from the gem and enhance the resulting color.

Over the last 30 years, Sri Lankan burners have refined locally produced furnaces—including the Lakmini—and gained extensive heat treatment expertise. The top practitioners in that country now rival those in Thailand, especially where low-temperature heating of corundum is concerned.

In early 2015, as a result of trade concerns, GIA researchers undertook two sessions of experimental low-temperature heat treatment of Mozambique ruby, one conducted in collaboration with burners in Sri Lanka and the other in Bangkok. For the latter, the temperatures reached ranged from approximately 550o to 750oC (1,022o to 1,382oF). The researchers confirmed that treatment caused a noticeable decrease of the blue color component in many samples.

These experiments aimed to determine whether low-temperature heating produced any detectable alterations to the treated gems’ inclusions, IR spectra, or chemical composition. The results appear in a study titled “‘Low-Temperature’ Heat Treatment of Mozambique Ruby - Results Report.”

Using high magnification and fiber-optic lighting, GIA researchers were able to show that many—though not all—inclusions were affected by low-temperature heating. In many cases, fractures appeared around crystals, with larger crystals the most affected. Mica, feldspar, and chalcopyrite inclusions showed the most alteration, with amphibole crystals showing the least. Fractures lined with limonite or iron staining might also appear darker after low-temperature heating.

Treatment caused modest but observable changes in peaks detected by FTIR spectroscopy at 3309 and 3161 cm-1. Trace-element analysis using LA-ICP-MS showed no significant change after treatment.

This study confirms that gemological laboratories have the capability to detect low-temperature treatment in rubies from Mozambique, especially with careful observation of inclusions and certain peaks in IR spectra. @chapter:9


Publication Year: 2017 Title: Peter J. Dunn (1942–2017) Abstract: Distinguished mineralogist and author Pete Dunn died November 8 at the age of 74. He is best known for the 134 new mineral descriptions he wrote over the course of his long career.

Dr. Dunn received his master’s degree and PhD in mineralogy/geology from the University of Delaware in Newark. Before joining the Smithsonian Institution’s National Museum of Natural History in 1972, he served in the U.S. Air Force and worked at Boston University as a curator in the geology department. In addition to characterizing new minerals, Dr. Dunn published a nine-volume monograph and more than 70 papers on the Franklin–Sterling Hill mining district in New Jersey in a number of scientific publications. In 1987, a member of the clinopyroxene subgroup from the Franklin mining district was named “petedunnite” in his honor. A prolific contributor to G&G throughout the 1970s, Dr. Dunn served on the journal’s editorial review board from its inception in 1981 until 1987. Upon his retirement from the National Museum of Natural History in 2008, he volunteered at the museum’s information desk until his death. @chapter:7


Publication Year: - Title: Exhibition Review: Jewels by JAR at the Metropolitan Museum of Art Abstract: This tulip brooch from 2008, displayed in the “Jewels by JAR” exhibit at the Metropolitan Museum of Art, is composed of rubies, diamonds, pink sapphires, garnets, silver, gold, and enamel. Photo by Jozsef Tari, courtesy of JAR, Paris.

                      Since November 20, 2013, the Metropolitan Museum of Art in New York City has hosted the “Jewels by JAR” retrospective, marking the Met’s first-ever show dedicated to a living contemporary jeweler. Bronx-born Joel Arthur Rosenthal, known professionally as JAR, is known to be very particular in his dealings with the outside world.  He does not lend his designs for magazine shoots or make red carpet appearances. Nevertheless, his jewelry is among some of the most sought after at auction, frequently fetching multi-million-dollar bids. The JAR retrospective, curated by Jane Adlin and displaying 395 pieces, is located in the Helen and Milton A. Kimmelman Gallery on the museum’s first floor, in its Modern and Contemporary Art galleries, which also house Matisse, Klee, and Picasso paintings.

The assembly of this jewelry collection is a rare event in itself, because of the sheer exclusivity of JAR’s work. Visitors are able to enjoy an ensemble of realistic, life-sized, multicolor pieces. JAR favors a floral theme (figure 2), and over a hundred examples are on display. Animal motifs are much less represented, numbering just over fifty. The dominant gemstones are diamonds, sapphires, rubies, and pearls. Some rare gemstones, such as sphalerite and alexandrite, are also displayed. JAR also masterfully reuses micromosaics, antique cameos, 18th century miniatures, and materials such as beetle wings in his designs. Titanium mountings, which allow the display of unusual metal colors such as blue and violet, have made him an innovator in the industry.

	Figure 2. Left: From 2001, diamonds, lilac sapphires, garnets, aluminum, silver, and gold are assembled to form this lilac brooch. Right: JAR created this geranium brooch (2007) using diamonds, aluminum, silver, and gold. Both pieces are from private collections. Photos by Jozsef Tari, courtesy of JAR, Paris.
The exhibit and associated merchandising events have stirred some controversy, with accusations that the Met, a world-class cultural institution, is acting as a commercial space. The JAR retrospective has also been pinned as a glorification of an elite taste for expensive objects.

Regardless, given the rarity of these pieces, this in itself makes this a remarkable event for the jewelry enthusiast. Gemologists will appreciate the superb quality of gemstones used by JAR in artful pavé-set creations. The splendor of rubies, diamonds, sapphires, and natural pearls in selected pieces is particularly striking (figure 3). The arresting quality of these objects makes up for the lack of mise-en-scène of the exhibit itself, which provides no signage other than a short biography of JAR. No organizing theme is established for the layout. While the connoisseur may be able to discern different themes, the general public is likely to be overwhelmed by the multiplicity of floral and animal pieces, as I witnessed during my visit. A simple booklet, featuring a succinct object list, is a welcome keepsake, though lacking jewelry dimensions and carat weight information. The scarcity of information is not solved by the exhibition catalogue, which only features 70 of the 395 pieces from this retrospective.

	Figure 3. Left: This JAR bracelet featuring diamonds, silver, and platinum, was created in 2010. Right: The camellia brooch, also from 2010, uses rubies, pink sapphires, diamonds, silver, and gold in its design. Both pieces are from private collections. Photos by Jozsef Tari, courtesy of JAR, Paris.
The exhibition’s pathway is circular and runs clockwise in a long oval room. The first collection consists of fifty floral pieces, mostly brooches; the ruby and diamond parrot tulip brooch is particularly alluring. This group is followed by an ensemble of sixty pairs of earrings, designed in more abstract and decorative patterns (figure 4). The second wall presents an assembly of unusual objects such as abstract pieces, boxes, sculptures, watches, and clocks. The hyperrealism, originality, and precision of some of these works shows JAR’s wide-ranging inspirations.  Certain pieces of this window display bring an unexpected element of surprise and humor in this solemn setting. The lettuce leaf and 18th-century micromosaic rabbit brooch (linked by a chain), along with the asparagus brooches, are worthy of notice.

	Figure 4. Left: JAR’s multicolored handkerchief earrings (2011) is an assemblage of sapphire, garnet, zircon, tourmaline, emerald, ruby, fire opal, spinel, beryl, diamond, platinum, silver, and gold. Right: This cameo and rose petal brooch, also from 2011, incorporates ruby, diamond, silver, and gold in its design. Both pieces are from private collections. Photos by Jozsef Tari, courtesy of JAR, Paris.
Visitors can also enjoy the objects set in 14 square-column window displays, with one or two pieces on each side. One of the most iconic jewels of this group is a zebra brooch comprised of agate, diamond, sapphire, silver, and gold (figure 5); a sheep’s head brooch, made of natural pearls, sapphire, and blackened silver and gold, is also intriguing. The exhibition continues with a rectangular window filled with 40 floral and vegetal pieces. The show concludes gracefully on a panel adorned with twenty butterfly brooches.

	Figure 5. Left: This poppy brooch from JAR (1982) is comprised of diamonds, tourmalines and gold. Right: The iconic zebra brooch from 1987 is made from agate, diamonds, sapphire, silver, and gold. Both pieces are from private collections. Photos by Katharina Faerber, courtesy of JAR, Paris.
While the general public may note the lack of scenography and description and therefore miss his artistry and craftsmanship, “Jewels by JAR” is a must-see for the jewelry enthusiast who wishes to become more familiar with these rare and eclectic masterpieces. @chapter:21


Publication Year: 2023 Title: The history of gemstones in Chanthaburi_25 Abstract: In addition to heat treatment, lapidary or gem cutting is another skill deeply rooted among the people of Chanthaburi. It is said that they have the ability to cut gemstones by hand to enhance their beauty, distinguishing them from many other countries with gemstone industries. @chapter:25


Publication Year: 2016 Title: Polymer-Coated Serpentine Abstract: Figure 1. The serpentine pendant before and after cutting. Photos by Lai Tai-An Gem Lab.

Jadeite, nephrite, serpentine, chalcedony, and quartzite were all referred to as “jade” in ancient China, where objects were defined by their craftsmanship rather than the materials themselves. The term is still widely used in the Chinese market for many types of materials. “Xiuyan jade” is actually a form of serpentine, so named for Xiuyan, a city in China’s Liaoning province where serpentine deposits are abundant.

The pendant in figure 1 was submitted to the Lai Tai-An Gem Laboratory by a client who claimed the material was jadeite jade. The pendant, which weighed 222.03 ct and measured 58 × 37 × 17 mm, showed a light green carved fish on a brown and yellow background. At first glance, it appeared to display a plastic-like luster.

Identical spot RIs of 1.56 were obtained from two different parts of the object, and an SG of 2.40 was determined. Both measurements were lower than expected for jadeite. The SG may have been affected by a polymer coating; this was partially confirmed when bubbles were observed on some surface areas under magnification. Microscopic observation proved that the piece was solid and not assembled. It was inert under long-wave and short-wave UV light from an ultraviolet viewing cabinet, whereas most polymer-coated objects show weak to strong reactions. The client granted permission to cut the piece in two for further analysis.

DiamondView observations of the cross section revealed an inert reaction from the object’s interior, but the coatings on the surface produced a strong bluish fluorescence (figure 2). FTIR spectroscopy on the interior identified the material as serpentine, but peaks at 3060, 3025, 2932, and 2858 cm–1, obtained from the surface, showed that a polymer was present. Peaks at 1045, 673, 564, and 485 cm–1, detected from both the interior and the surface, were indicative of serpentine (figure 3); this was confirmed by Raman spectroscopy.

Figure 2. DiamondView imaging showed that the inner portion of the serpentine was inert, while the surface exhibited a strong bluish fluorescence. These images show the reflection from the polymer-coated surface in visible (left) and UV light (right). Images by Lai Tai-An Gem Lab.

Figure 3. FTIR spectroscopy revealed peaks indicative of coating at 2858, 2932, 3025,
and 3060 cm–1 (red) and serpentine peaks at 485, 564, 673, and 1045 cm–1 (blue).
Coatings are normally applied to gem materials to improve luster and, in some cases, provide a degree of stability. This was the first case of coated serpentine we have encountered. Care should be taken to identify such coatings; the simplest way to detect the treatment is to check for any unusual reaction under the ultraviolet viewing cabinet, but in this case, the UV reaction only showed in the ultra-short-wave UV of the DiamondView. Serpentine’s characteristically low hardness makes it a very suitable carving material, but any treatments applied to it should be fully disclosed. @chapter:37


Publication Year: 2011 Title: The Chinese Red Feldspar Controversy: Chronology of Research Through July 2009 Abstract: Red copper-containing plagioclase feldspar from Oregon has been available for over a century. In the early 2000s, new localities for copper-bearing feldspar were reported from the Democratic Republic of the Congo and from Tibet or an unspecified locality in China. The new material has been the subject of widespread concerns about its geographic origin and natural color. In fact, extensive studies of its composition, spectroscopy, physical appearance, and isotopic properties suggest that much of the red andesine on the market is the product of laboratory diffusion of copper into pale yellow andesine from Inner Mongolia. All samples initially subjected to testing as part of this study gave strong evidence or suggestions of treatment. Traces of copper-containing fluxes found on rough stones, and measurements of argon isotopic composition in particular, demonstrate that the tested material was recently heated to high temperatures under conditions where copper diffusion could occur. These results apply to samples that were obtained through July 2009, but do not include samples from expeditions to Tibet in 2010.

	DATA DEPOSITORY

Electron Microprobe Analyses of Red Andesine from Various Sources
	May 2, 2011 @chapter:5


Publication Year: 2004 Title: Cultured Pearls from the Gulf of California, Mexico Abstract: Black pearls have been found in Mexico’s Gulf of California since the area was settled more than 2,000 years ago. Attempts at culturing pearls in this area have met with varying success over the past century. Today, a pearl farm in Guaymas is producing commercial quantities of mabe as well as bead-nucleated full-round cultured pearls from the indigenous pearl oyster Pteria sterna. This article provides an overview of the history of natural and cultured pearls from Mexico, describes pearl culturing at the Guaymas farm, and focuses on the properties of bead-nucleated cultured pearls from P. sterna. These cultured pearls have a brown or gray to dark gray body color with various interference colors caused by the stacking of platy aragonite crystals and organic matter. One indication of their natural color (and their Mexican provenance) is a red fluorescence to long-wave UV radiation. @chapter:14


Publication Year: 2015 Title: Diamond-Bearing Eclogite Xenoliths from the Ardo So Ver Dykes Abstract: Figure 1. These five diamond-bearing eclogite xenoliths from the Ardo So Ver dykes in South Africa ranged in weight from 2.24 to 12.40 grams, with the largest measuring 2.5 centimeters in length. Photo by Kevin Schumacher.

              Specimens of gem diamond crystals in rock matrix are almost never found due to the rigorous processing that occurs during diamond mining. Occasionally, a diamond is found in a sample of the kimberlite host rock that brought it to the surface, but finding a diamond in the rock in which it likely crystallized in the earth’s mantle is extremely rare. When pieces of the mantle break off and are transported to the surface in a kimberlite magma, they are called xenoliths (meaning “foreign rock,” because the mantle rocks are not formed from the kimberlite magma itself).

Recently, five small rock samples containing diamond crystals (figure 1) were sent to GIA Research for examination. The samples were submitted by Charles Carmona (Guild Laboratories, Los Angeles) on behalf of owners Jahn Hohne (Ekapa Mining, Kimberley, South Africa) and Vince Gerardis (an occasional trader and collector of unique diamonds and producer of the television series “Game of Thrones”). The specimens were sourced over 25 years ago from a kimberlite fissure mine located 40 miles (65 km) northwest of Kimberley, South Africa. The So Ver mine is located in a group of narrow kimberlite dykes discovered in the 1940s, known as the Ardo dykes, that intruded into Ventersdorp lavas and overlying Karoo shales (M. Field et al., “Kimberlite-hosted diamond deposits of southern Africa: A review,” Ore Geology Reviews, Vol. 34, 2008, pp. 33–75).

Mineralogical examination using microscopy and Raman spectroscopy revealed that the rocks were composed primarily of garnet and clinopyroxene and would be classified as eclogite xenoliths (figure 2). In simple terms, eclogites are metamorphic rocks, typically created when basaltic crust from the ocean floor is subducted deep into the earth’s mantle where high temperatures and pressures cause chemical reactions that change the basaltic minerals into garnet and clinopyroxene. Eclogites, along with peridotites, are considered the most common mantle host rocks for diamond crystallization. EDXRF chemical analysis of the garnets and clinopyroxenes in these samples showed pyrope mole fractions up to about 49% and jadeite mole fractions up to approximately 31%. These results are consistent with other reported diamond-bearing eclogites (T.F. Fung and S.E. Haggerty, “Petrography and mineral compositions of eclogites from the Koidu Kimberlite Complex, Sierra Leone,” Journal of Geophysical Research, Vol. 100, 1995, pp. 20451–20473).

Figure 2. These five diamond-bearing eclogite xenoliths from the Ardo So Ver dykes in South Africa ranged in weight from 2.24 to 12.40 grams, with the largest measuring 2.5 centimeters in length. Photo by Kevin Schumacher.
The diamond crystals in the xenoliths ranged from 1.5 to 4.0 mm in length, and were transparent and near-colorless to pale yellow (figure 3). They occurred as octahedral and combination forms with no visible resorption. No inclusions were visible within the crystals under 10× magnification. FTIR analysis (using an FTIR microscope in reflected light mode) revealed that all of the diamonds were type Ia with abundant nitrogen impurities. Three of the seven diamonds analyzed showed nitrogen impurities dominantly as A-aggregates in concentrations ranging from approximately 420 to 800 ppm.

Figure 3. Seven transparent, near-colorless to pale yellow gem diamonds (five shown in these photos) were observed in the eclogite samples, ranging in length from 1.5 to 4.0 mm. Photos by Christopher M. Breeding.
The data provided here, along with additional ongoing work, will hopefully shed more light on the temperature, pressure, and depth in the earth’s mantle where the diamonds crystallized. @chapter:29


Publication Year: - Title: The Magic of Colored Diamonds Abstract: One of the most famous gems in the world, The Hope Diamond is a 45.52 carat Fancy Deep grayish blue diamond. GIA researchers examined it in 1988. Photo: Chip Clark, courtesy of Smithsonian Institution.

Colored diamonds are in the spotlight. They’re routinely breaking records at auction houses. They make headlines when set in celebrity engagement rings. And they’re gemological marvels of the rarest order.
Seen in practically every color of the rainbow, colored diamonds are far rarer than diamonds in the D-to-Z color range. Only one out of 10,000 carats of fashioned diamonds displays fancy color, and a diamond’s chances of displaying intense color are even less – one in 25,000. Browns and yellows are the most common fancy colors. Red, green, purple and orange are the rarest.
GIA® issued its first origin-of-color reports for colored diamonds in 1956. Backed by decades of research and the examination of thousands of colored diamonds, the GIA Colored Diamond Grading System has become the standard for evaluating these extremely rare gems. Current GIA Colored Diamond Grading Reports describe color grades using these terms: Faint, Very Light, Light, Fancy Light, Fancy, Fancy Dark, Fancy Intense, Fancy Deep and Fancy Vivid. Virtually every colored diamond sold at major auction houses has been graded by GIA.

GIA Colored Diamond Reports for natural diamonds provide color grade and color origin (natural vs. treated color), clarity, carat weight, and additional information. Learn more at GIA.edu/colored-diamond-grading
“The GIA Colored Diamond Grading System allows a much more detailed description of diamond color than what had been available under the previous grading system. This has greatly facilitated trading of such stones worldwide, particularly as new sources expanded the quantities of stones in the market and the range of colors,” observed Russ Shor, senior industry analyst at GIA.
Pink
GIA researchers theorize that the color in many pink diamonds is caused by color centers that can selectively absorb light in the visible region of the spectrum. Color centers are the result of lattice defects, or imperfections in the arrangement of atoms in a crystal. These defects can sometimes cause pink graining in the diamond crystal.

The GIA-graded 59.60 carat Pink Star diamond sold for $71 million at the April 4, 2017 Sotheby's auction in Hong Kong. GIA researchers have not definitively determined the origin of this magnificent diamond’s pink color. Courtesy: Sotheby’s
Black
Most naturally colored black diamonds get their color from large quantities or clouds of minute mineral inclusions such as graphite, pyrite or hematite that extend throughout the stone. These diamonds may also have numerous cleavages or fractures that are stained black or have become black because of graphitization. Concentrations of these internal features are responsible for the coloration. However, the actual body color of a natural black diamond may range from near-colorless to brown or “olive” green.

This 67.50 carat black diamond was discovered in India, and was originally 195 carats before being cut into three pieces.
Yellow
The presence of nitrogen causes a diamond to appear yellow. The intensity of the yellow color is dependent upon varying amounts of nitrogen. Yellow diamonds are considered to be a colored diamond and graded as “Fancy” when they fall outside the D-to-Z range (colorless to light-yellow).

This Fancy Intense yellow cushion-cut diamond weighing 54.29 carats is the star in this necklace, while another 67.10 total carat weight of diamonds create a sublime contrast. Courtesy: Chatila
Brown
Once relegated to industrial use, brown diamonds gained cachet in the 1980s when marketers gave them romantic names like champagne, cognac and chocolate. The color in natural brown diamonds is caused by internal parallel brown grain lines due to distortion of the crystal lattice (arrangement of molecules). Brown diamonds are generally more affordable compared to other fancy colors.

18K white gold ring featuring 1.15 carat brown diamond and 0.15 carats of diamonds at halo and shank. Courtesy: TheRealReal.com
Blue
The presence of boron impurities is often responsible for the color of natural blue diamonds. The more boron, the deeper the blue. However, their color can also be caused by radiation exposure or associated with hydrogen. India was historically the source for blue diamonds. Within the last several years, notable blue diamonds have been found at the Cullinan Mine in South Africa.

The flawless, Fancy blue pear-shaped, 13.22 carat Winston Blue, graded by GIA, was sold for $1.8 million per carat at a Christie's May 14, 2014 Geneva auction. Courtesy: Christie’s
Red
Only a handful of red diamonds larger than 5 carats have been found. Red diamonds are so rare that from 1957 to 1987 GIA did not issue a lab report for a diamond with “red” as the only descriptive term. “Predominantly red” means that red is the primary color with no secondary hues (like purple). GIA researchers, who have been studying diamonds for decades and have access to the most sophisticated equipment, are still not sure what causes their color.

The 5.11 carat Fancy red, triangular brilliant cut Moussaieff Red diamond was discovered in 1990 in Brazil.
Green
Green diamonds get their color when radiation displaces carbon atoms from their normal positions in the crystal structure. This can happen naturally when diamond deposits lie near radioactive rocks, or artificially as a result of treatment by irradiation. Naturally colored green diamonds are extremely rare. Because of their rarity and the very real possibility of treatment, green diamonds are always regarded with suspicion and examined carefully in gemological laboratories. Even so, advanced gemological testing can’t always determine color origin in green diamonds. Examined by GIA Researchers in 1988, the 41 ct Dresden Green diamond is the largest, and perhaps the finest, green diamond known to have a color of natural origin.

Examined by GIA researchers in 1988, the 41 carat Dresden Green diamond is the largest, and perhaps the finest, green diamond known to have a color of natural origin.
Synthetic Colored Diamonds
In recent years, gem-quality synthetic colored diamonds have come to market. A Russian company, New Diamond Technology, produced a 10.08 carat diamond with a color grade equivalent to Fancy Deep blue, which GIA examined in September 2016. GIA also offers Synthetic Colored Diamond Grading Reports for synthetic colored diamonds.
Colored diamonds are exceedingly rare and exceptionally beautiful. Because of this, interest in them is not likely to wane. Expect these rarities of the highest order to continue to captivate gem aficionados and the public. @chapter:31


Publication Year: - Title: Alumni Association Japan President’s Goal: Creating Connections for Graduates Abstract: Dr. Ken Fujita, GIA GG, who counts Paraíba tourmaline and ruby among his favorite colored stones, urges GIA students to take advantage of the “thousands of stones to identify and practice with” in Graduate Gemologist classes. Photo courtesy of Ken Fujita

Most newly appointed executives – especially those who have just taken the reins of their family’s fourth-generation company – expect leadership challenges on every front, from marketing and sales to operations and logistics.
For Dr. Ken Fujita, GIA GG, the early days of his tenure as president and CEO of his family’s Tokyo-based jewelry wholesaling company, Fujita Co., Ltd., were marked by a different sort of leadership trial: the aftermath of the largest earthquake in Japan’s history.
Fujita was leading a late-afternoon corporate meeting with a partner department store in Tokyo on March 11, 2011 when the shaking started.
“I’ve been through thousands of earthquakes in my life, but the size of this shake was unusual,” Fujita says.
He stopped the meeting and led attendees out to the department store retail area, where mannequins were falling, and customers and retail associates were dropping to the ground and crying. Fujita helped people evacuate to the exit floor; he could not return to his home for the next 24 hours.
Transportation was down across the city after the magnitude 9.1 Tōhoku quake, and the tsunami and nuclear disaster that followed only increased the challenges that Japan would face. But Fujita, who was appointed to his position just after the quake, was determined to lead – and guide his employees through the difficult days, weeks and months ahead.
“We worked harder and harder,” he says. “We had to work beyond the crisis, and think beyond the disaster.” Fujita Co., Ltd., which wholesales with department stores – providing colored stones, jewelry and even sales associates – weathered the crisis, maintaining a healthy business through tumultuous times.
Fujita’s sense of responsibility and leadership likely comes from the fact that Fujita Co., Ltd. was entrusted to him by his father, Sadaharu Fujita, whose own grandfather founded the family business in 1920 as a silver ornament and tableware company.
After World War II, Sadaharu Fujita’s father, Teiichi, expanded the company to jewelry wholesale, and when he took over, he began to import colored stones.
Sadaharu Fujita – who also served as president of the International Colored Stone Association from 1991-1995, instituting the NET system of treatment and enhancement identification – planned to pass the business to his son, Ken, with one qualification: he had to attend GIA to earn his Graduate Gemologist diploma and polish his English skills.

Dr. Ken Fujita, lower right, still has the first-place medal he and his classmates won at a campus-wide volleyball tournament at GIA’s Carlsbad campus in 2002. Fujita, who serves as president of the GIA Alumni Association Japan, says that the friendships he made during his time as a student are one of the highlights of his GIA experience.
Ken Fujita, who already had a PhD in organic chemistry from Tokyo University of Science, moved to Carlsbad and earned his GG in 2002, which he followed up with jewelry design and business classes. He found that learning about such a large variety of gemstones in just six months was both helpful and efficient.
“It was a great opportunity to train my identification skills,” Fujita says. “There are thousands of stones to identify and practice with. In the real world of business, you can’t make mistakes – but the courses offer you the opportunity to make those mistakes and learn from them.”
But for Fujita, the best parts of his GIA experience were the friendships and connections that began there, and continue today.
“Those relationships are so important and meaningful,” he says.
Fujita was appointed as president of the GIA Alumni Association’s Japan chapters in 2010 after his mentor, Yoshiko Doi, suggested it. He is committed to helping foster relationships and networking opportunities between other GIA graduates across Japan.

GIA President Susan Jacques, left, joined Dr. Ken Fujita, GG, at the GIA Alumni Association Japan’s 25th anniversary celebration. Fujita says he wants to make the eight Japanese alumni chapters “a very comfortable place for alumni” where they can foster personal and professional connections. Photo courtesy of Ken Fujita
“After GIA graduation, we can help them make those connections,” he says. “I want to make our chapters in Japan a very comfortable place for alumni. The GIA Alumni Association is a place where graduates can connect with a new supplier or client, make a new friend, or educate themselves with new and ongoing developments in the trade.”
Fujita says those interested in entering the gem and jewelry industry should pursue a GIA education, regardless of whether they have an established family history.  “The designation of GG is a very important ‘passport’ in our industry to identifying a respected, trustworthy professional,” he says.
He also offered some advice on how to stay ahead to those already in the business: “Deal with only beautiful pieces … and I don’t mean only expensive items,” he says. “I think beauty is the key to survive in the industry.” @chapter:34


Publication Year: 2014 Title: Coated Lawsonite Pseudomorphs Presented as Chromian Lawsonite Abstract: Green (chromium-bearing) lawsonite first appeared on the mineral market in 2011–2012. It came from an undisclosed locality on the Greek island of Syros. The only large chromian lawsonite crystals previously documented are from Turkey (S.C. Sherlock and A.I. Okay, “Oscillatory zoned chrome lawsonite in the Tavsanli Zone, northwest Turkey,” Mineralogical Magazine, Vol. 63, No. 5, 1999, pp. 687–692) and the western Alps (C. Mevel and J.R. Kienast, “Chromian jadeite, phengite, pumpellyite, and lawsonite in a high-pressure metamorphosed gabbro from the French Alps,” Mineralogical Magazine, Vol. 43, No. 332, 1980, pp. 979–984). The maximum crystal size observed by Sherlock and Okay was approximately 500 microns, while Mevel’s and Kienast’s largest grains were only 200 microns in length. Interestingly, these grains were reported to be pink. Samples available online ranged from US$50 to more than US$350, and all were reported to be from Syros. To the best of our knowledge, chromian lawsonite is not available from other localities.

We purchased a chromian lawsonite sample purportedly from Syros for mineralogical analysis (figure 1). The sample measured 4.8 × 2.8 × 2 cm, and its largest crystal was about 1.5 cm in length. The crystals were deep green and present in a matrix dominated by ankerite and actinolite. Our sample appeared similar to most other chromian lawsonite samples available for purchase online.

Figure 1. These large green crystals were reported as chromian lawsonite. Ankerite (orange) and actinolite (light green) are the major matrix minerals between the large green crystals (verified by Raman spectroscopy). The specimen is 4.8 cm long. Photo by Earl O’Bannon.
Initial microscopic observations of the large green crystals revealed a smooth wavy surface (figure 2). Raman analysis of this surface showed peaks at 1301, 1342, 1451, and 2720 cm–1 and a broad peak at 2800–3000 cm–1 with secondary peaks at 2871, 2932, and 2961 cm–1 (figure 3). These peaks are typical of Group B fillers (strong aliphatic peaks), which have been used to enhance the appearance of emeralds (M.L. Johnson et al., “On the identification of various emerald filling substances,” Summer 1999 G&G, pp. 82–107). The absence of Raman peaks in the approximately 1600 cm–1 region indicates that this coating is not likely a Group A, C, D, or E filler (Johnson et al., 1999; L. Kiefert et al., “Raman spectroscopic applications to gemmology,” Handbook of Raman Spectroscopy, Vol. 28, 2001, pp. 469–490). This smooth surface was waxy to the touch and easily scratched with a fingernail, and wiping it off with acetone revealed a light green to white surface. All peaks associated with this coating disappeared after cleaning with acetone (again, see figure 3).

Figure 2. The photo on the left (magnified 1.25×) shows a fingernail scratch on the surface. The photo on the right (magnified 1.6×) shows pooling of the coating in a depression in the grain. Photos by Earl O'Bannon.

Figure 3. Raman spectra of the coating before and after cleaning the surface with acetone. Spectra were taken in the same location, with an approximately 2 micron spot size. The typical Raman spectrum of quartz, with clinochlore contamination, is observed in the low-frequency region. Spectra are offset for clarity.
After the coating was removed, Raman analysis of the formerly dark green crystals revealed spectra corresponding to the minerals muscovite/phengite, clinochlore, and quartz (figure 4). About a hundred measurements were taken of all the large green crystals in the sample at the 2 micron scale-length, and no evidence of lawsonite was found. This assemblage of minerals is common in lawsonite pseudomorphs from Syros; prograde pseudomorphs, also containing zoisite and 0.5–3.0 cm in size, are reported to be abundant in this locale (J.B. Brady et al., “Prograde lawsonite pseudomorphs in blueschists from Syros, Greece,” GSA Annual Meeting, 2001, paper 105-0).

Figure 4. Raman spectra of acetone-cleaned large green crystals (bottom three spectra). Mica and clinochlore are the most abundant minerals in the large green crystals. The reference lawsonite spectrum is for a sample from the UCSC mineral collection (sample no. 6481), from Valley Ford in Sonoma County, California. Spectra offset for clarity.
We conclude that this sample is composed of lawsonite pseudomorphs, which were coated to make them appear deep green and imitate chromian lawsonite crystals. The euhedral crystals consisted of a fine-grained mixture of muscovite, clinochlore, and quartz. It is not known whether this sample was coated with the recognition that these were lawsonite pseudomorphs.

All samples of chromian lawsonite that we have found for purchase are from Syros. Thus, buyers should be aware that these could potentially be artificially coated lawsonite pseudomorphs. Further analysis of other “chromian lawsonite” samples is required to document whether any true chromian lawsonites from this locality actually exist. @chapter:13


Publication Year: 2017 Title: Pink Sapphire Filled with Bismuth-Based Glass Abstract: Figure 1. This 2.77 ct light pink sapphire cabochon was treated with a bismuth-based glass filling. Photo by Nuttapol Kitdee.

	Recently, GIA’s Bangkok laboratory received a 2.77 ct light pink sapphire (figure 1) for an identification report. The sample was a semi-transparent cabochon with natural inclusion features: silk needles and particles, twinned planes, and thin films. Also observed throughout the stone were numerous gas bubbles of various shapes and sizes that were trapped along surface-reaching fractures and cavities (figure 2). These indicate the presence of glass filling. However, no flash effect was evident in the filled fractures. The stone’s refractive index of 1.76 and UV fluorescence reaction (medium red to long-wave and weak red to short-wave) were consistent with corundum. Its specific gravity of 3.87 was lower than that of corundum and possibly a result of the filler. Due to the sapphire’s very light color, its visible-range absorption spectrum was difficult to observe.

	Figure 2. With the aid of fiber-optic illumination, magnification revealed these trapped gas bubbles of various shapes and sizes in the light pink sapphire. Photo by Charuwan Khowpong; field of view 2.00 mm.

	Qualitative chemical analysis using energy-dispersive X-ray fluorescence (EDXRF) spectroscopy showed the presence of bismuth in addition to the expected Al, Cr, Fe, and Ga. No lead was detected in the sample, even with the aid of the thick palladium filter. The chemical composition of the filler indicated that the stone had undergone fracture filling using bismuth-based glass (“Ruby treatments – revisited, with Mozambique’s perspective,” Lab Information Circular, Gem Testing Laboratory, Vol. 63, December 2011). Due to the large difference in refractive indices between the bismuth-based glass filled area and the surrounding corundum, this treatment was easier to visually detect than lead-glass filling (figure 3).

	Figure 3. Under reflected illumination, the pink sapphire’s large cavity filling was readily visible with the unaided eye. Photo by Charuwan Khowpong; field of view 2.70 mm.

	Fracture filling with lead glass and non-lead glass has been widely used in low-grade ruby (S.F. McClure et al., “Identification and durability of lead glass–filled rubies,” Spring 2006 G&G, pp. 22–34). Pink sapphires such as this 2.77 ct stone are less commonly encountered in the laboratory for examination and identification. @chapter:12


Publication Year: 1988 Title: The Sapphires of Penglai, Hainan Island, China Abstract: The sapphire deposit at Penglai, on Hainan Island, is potentially the largest in China. Gem-quality sapphires, at least one as large as 35.5 ct, have been found in alluvial gravels approximately 2 km southeast of the city of Penglai. Gem-quality zircon and a few pieces of what might be considered ruby have also been recovered in the course of the geologic study of this area, which has not yet been commercially developed. The average size of the sapphires is 2—5 mm. They are similar in appearance and gemological properties to sapphires from Australia, Thailand, and Kampuchea. @chapter:0


Publication Year: 2014 Title: Flame-Fusion Synthetic Ruby Boule with Flux Synthetic Ruby Overgrowth Abstract: Synthetic rubies with both curved growth and flux-type inclusions in a single stone occasionally appear in the trade. Often these are flame-fusion synthetics that have been quench-crackled and flux-healed to produce a more “natural” appearance. In other instances, flame-fusion material may be used as a seed for flux corundum overgrowth. If the seed crystal is not removed during cutting, it becomes part of the faceted synthetic gemstone (R.E. Kane, “A preliminary report on the new Lechleitner synthetic ruby and synthetic blue sapphire,” Spring 1985 G&G, pp. 35–39).

The Carlsbad laboratory recently examined a 249.78 ct transparent to semi-transparent rough red crystal (figure 1). Standard gemological testing using a handheld spectroscope revealed a typical ruby spectrum. Observed with a dichroscope, the rough crystal displayed medium orange red to purplish red pleochroism and fluoresced strong red to long-wave UV and medium red to short-wave UV. All of these properties were consistent with ruby.

Figure 1. This 73.69-mm-long synthetic ruby crystal is composed of a flame-fusion synthetic ruby boule core with a flux synthetic ruby overgrowth. Photo by Nathan Renfro.

Figure 2. Subtle curved striae (right arrow) and fingerprint-like flux residue (left arrow) are indicative of both flame-fusion and flux growth. Photomicrograph by Nathan Renfro; image width 6.94 mm.
Microscopic examination using brightfield illumination revealed both curved striae and flux fingerprint patterns (figure 2). Careful examination of one end of the rough crystal showed a noticeable boundary between a flame-fusion core and a flux-grown overgrowth. Part of the core had not been covered by the flux overgrowth (again, see figure 1). The flux fingerprint inclusion penetrated just a few millimeters into the crystal and was only visible in the flux overgrowth (again, see figure 2). What appears to be a pronounced dark grayish reaction zone at the interface of flame-fusion and flux growth was observed (figure 3). The reaction zone likely indicates slight structural and chemical variations between the flame-fusion core and the flux overgrowth. When a new crystal is grown on top of an old crystal, the new growth starts on an irregular surface that was created when the old surface was melted back slightly at the melt temperature. When growth starts on an irregular surface, it creates a non-perfect crystal lattice match between the original seed and new overgrowth. This growth boundary face will disrupt the regularity of the structure of the growth crystal and contribute to the presence of the reaction zone (Schmetzer et al., “Flux-grown synthetic alexandrites from Creative Crystals Inc.,” 2012, Journal of Gemmology, Vol. 33, No. 1–4, pp. 49–81). In areas where the structural and chemical difference was not very distinct, the reaction zone was partially visible as dark grayish color patches (figure 4). The reaction zone looked grayish because the red bodycolor of the ruby masked what is probably a blue color zone caused by Ti-Fe pairs, a well-known defect that causes blue color in corundum (Summer 1991 Lab Notes, p. 112). The blue zone is along the interface of the flame-fusion core and flux overgrowth.

Figure 3. A dark grayish reaction zone was observed between the flame-fusion core and the flux overgrowth. Photomicrograph by Nathan Renfro; image width 15.67 mm.

Figure 4. Also observed was a partial reaction zone between the flame-fusion core and the flux overgrowth. Photomicrograph by Nathan Renfro; image width 5.85 mm.
Advanced testing on the rough crystal using energy-dispersive X-ray fluorescence (EDXRF) analysis revealed traces of Ca, Ti, and Cr in the areas both with and without flux overgrowth; Mo was only detected in areas with the flux overgrowth. The concentration of Fe was below the detection limit of EDXRF. This result is consistent with the chemical element differences between flame-fusion and flux synthetics (S. Muhlmeister et al., “Separating natural and synthetic rubies on the basis of trace-element chemistry,” Summer 1998 G&G, pp. 80–101).

This synthetic ruby specimen is unusual in that regions originating from the two growth methods occur in the same crystal, with the half of the split boule seed crystal composing the bulk of the entire specimen. While flux overgrowth on flame-fusion seed crystals has been previously reported (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Volume 2, Opinion Verlag, Basel, Switzerland, 2005, p. 352), this type of material is rarely seen in GIA’s laboratory, and this example was particularly unusual due to its large size. @chapter:12