Publication Year: - Title: Pardieu Shares Tales of Afghan Gem Exploration Abstract: Change your look: grow a beard, dress like a local, take off your glasses.

Get a reliable local contact to be your guide.

And, most importantly, find a way to connect with the people you meet along your journey.

These are some of the precautions Vincent Pardieu, supervisor of field gemology for GIA, takes when he travels to Afghanistan to learn more about the rubies, emeralds and sapphires mined in this rich gem-producing country. He shared these tips – along with the fascinating history of gem trading on the Silk Road (the ancient route from Asia to the Middle East) and the consequences of multiple wars and politics in Afghanistan – with students and staff in Carlsbad recently.

Pardieu often travels directly to the source to verify the origin of gemstones, including observing and photographing mines and mining techniques, collecting reference samples and GPS data, and documenting his findings in expedition reports. His work is critical in order for GIA to provide origin determination reports, particularly for rubies, sapphires and emeralds.

Pardieu’s journeys may be risky, but he clearly thrives in an environment that enables him to tap into his love of travel, gemstones and learning the stories of the people he meets along the way. He has traveled to Afghanistan five times since 2006, collecting thousands of samples for GIA research.

He said he makes an effort to blend in – the clothes, the beard, etc. – and always travels with people he knows who can provide him with reliable local contacts.

“If you make a mistake on a stone, you maybe will lose a little money,” he said. “If you go to a country you don’t know and you make a mistake on a person – or you get associated with the wrong person – then it starts to be scary,” he said.

Afghan miners have been selling gemstones to foreigners for generations, Pardieu added. “They like foreigners because they bring them some money.”

It’s the people sitting at the next table for lunch, or the ones you meet along the road you have to be careful of, he said, noting that the return from a gem mine is often more dangerous than getting there.

“If you get noticed, you might get ambushed on the way back,” he said.

The first step Pardieu and his team make when they reach the village closest to the mine they want to go to is to meet with the elders. This could take some time, as they are often extremely curious about visitors and skeptical about their intentions. The elders have the final say on whether or not they can go to the mine.

“You have to find a way to connect with the people, then they will help you,” he said. If they are hunters and you like to hunt, make that connection. Use whatever clue you pick up on. “If you can’t find a way to make a connection, you are in trouble.”

Rubies from Jegdalek
Pardieu traveled to Afghanistan’s Jegdalek mines twice, once in 2006 and again in 2010, but was not able to see any mining activity on either trip. The first time the mines were closed by the government, and the second time his group was being watched by an unknown man on another hilltop and the team decided to turn around.

He was able to get ruby samples from the mine owner – after five hours of lunch, tea and questions about his life. Though a little taken aback by the amount of time he had to talk about himself before he could buy gems, Pardieu said miners are hungry for news of any kind.

Emeralds from Panjsher
Pardieu, curious why only small emeralds seemed to come out of Afghanistan’s Panjsher mines, wanted to “see with his own eyes” why. He visited the Panjsher Valley and found hundreds of mines carved into a large vein located 1,000 vertical meters above the closest village. He also learned a lot about the way the mines operate.

The miners “race around underground,” trying to be first to blast their way to the good spots, he said. Whoever gets to a tunnel first wins – or owns – that tunnel.

“There is always one guy listening on the wall to find out where the others are working,” he said. “When there is no more noise, it means they are going to blast and you need to run. If they break into your tunnel, you win – but you have to survive the blast to win.”

Buying explosives is difficult for miners in Afghanistan, so they make their own by adding farm fertilizer to munitions left behind when the Soviets bombed the valley in the 1980s. This explains the small emeralds, Pardieu said. The shock waves from these explosives damage most of the production.

“It’s all about finding the emerald that survived the blast,” he said.

Sapphires from Badakhshan
Working at the GIA lab, Pardieu found that sapphires from the Badakhshan area had inclusions of tourmaline. Until then, he had only known of this type of sapphire from Kashmir. So he set off to the mines to investigate.

He and his team were not physically able to get to the sapphire source because access is extremely limited. The path to the mine, located on a cliff 1,000 meters above a lapis lazuli mine, is unstable and accessible only from 3-9 a.m. for two months in the summer. Once the sun shines on the cliff, rocks fall down and it becomes very dangerous.

He was able to buy 10 kilos of rough in matrix – including mica, tourmaline and sapphire – for study.

Pardieu’s Last Tip:
Never forget to wish the miners good luck, Pardieu advises. Two hours after he left the Panjsher Valley emerald mine, the miners hit a deep pocket.

“If they find some stones after you leave, they will be very happy when you come back,” he said. @chapter:22


Publication Year: 2021 Title: Chanthaburi:The city of gem_15 Abstract: As for the method of gemstone faceting, I started with no knowledge. Being in Chanthaburi, I became a gemstone faceter and trained for many decades. Eventually, I understood the technique of setting water because gems, unlike diamonds, require water setting. @chapter:25


Publication Year: 1982 Title: Winter 1982 Gem News International Abstract: Mineralogists Adopt Gemological Concerns

Diamond Source Assumption Assailed

Exhibits
            Smithsonian Institution/Freer Gallery of Art
            Smithsonian Institution/Cooper-Hewitt Museum

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


Publication Year: - Title: Tourmaline Description Abstract: The intense green of this chrome tourmaline from Tanzania resembles the color of emerald.

                      Tourmalines come in a wide variety of exciting colors. In fact, tourmaline has one of the widest color ranges of any gem species, occurring in various shades of virtually every hue.

Many tourmaline color varieties have inspired their own trade names:

		Rubellite is a name for pink, red, purplish red, orangy red, or brownish red tourmaline, although some in the trade argue that the term shouldn’t apply to pink tourmaline.

		Indicolite is dark violetish blue, blue, or greenish blue tourmaline.

		Paraíba is an intense violetish blue, greenish blue, or blue tourmaline from the state of Paraíba, Brazil.

		Chrome tourmaline is intense green. In spite of its name, it’s colored mostly by vanadium, the same element that colors many Brazilian and African emeralds.

		Parti-colored tourmaline displays more than one color. One of the most common combinations is green and pink, but many others are possible.

		Watermelon tourmaline is pink in the center and green around the outside. Crystals of this material are typically cut in slices to display this special arrangement.

	The colors displayed by the crystal and fashioned gem are typical of tourmaline with the trade name of rubellite. - Courtesy William F. Larson, Pala International

	Copper is the element that contributes to this Paraíba tourmaline’s highly prized color.

	This attractive slightly brownish, orangy yellow tourmaline is from the Merelani area of Tanzania.

	Some tourmaline crystals display different color zones within a single crystal. - Jeff Scovil
Some tourmalines also show a cat’s-eye effect called chatoyancy. Cat’s-eye tourmalines are most often green, blue, or pink, with an eye that’s softer and more diffused than the eye in fine cat’s-eye chrysoberyl. This is because, in tourmaline, the effect is caused by numerous thin, tube-like inclusions that form naturally during the gem’s growth. The inclusions are larger than the inclusions in cat’s-eye chrysoberyl, so the chatoyancy isn’t as sharp. Like other cat’s-eyes, these stones have to be cut as cabochons to bring out the effect.

A tourmaline’s chemical composition directly influences its physical properties and is responsible for its color. Tourmalines make up a group of closely related mineral species that share the same crystal structure but have different chemical and physical properties. They share the elements silicon, aluminum, and boron, but contain a complex mixture of other elements such as sodium, lithium, calcium, magnesium, manganese, iron, chromium, vanadium, fluorine, and sometimes copper.

Gemologists use a tourmaline’s properties and chemical composition to define its species. The major tourmaline species are elbaite, liddicoatite, dravite, uvite, and schorl.

Most gem tourmalines are elbaites, which are rich in sodium, lithium, aluminum, and sometimes—but very rarely—copper. They occur in granite-containing pegmatites, which are rare igneous rocks. Pegmatites are sometimes rich in exotic elements that are important for the formation of certain gem minerals.  Pegmatites might contain very large crystals up to 1 meter (about 3 feet) in length. Because of the nature of pegmatites, different gem pockets within one pegmatite body can hold tourmaline crystals of very different colors. Or one pocket can produce a variety of differently colored tourmalines. As a result, many mines produce a variety of gem colors.

Another feature of gem pegmatites is the scattered distribution of pockets within them. For miners, working a pegmatite consists mostly of excavating barren rock until the work results in the occasional and sudden reward of a rich pocket full of spectacular gem crystals.

Elbaites offer the widest range of gem-quality tourmaline colors. They can be green, blue, or yellow, pink to red, colorless, or zoned with a combination of colors.

Liddicoatite is rich in calcium, lithium, and aluminum. It also originates in granite-containing pegmatites and offers a diverse array of colors, often in complex internal zoned patterns. It’s named after the late Richard T. Liddicoat, former president of GIA and former chairman of its Board of Governors. He’s often referred to as the “Father of Modern Gemology.”

Uvite is rich in calcium, magnesium, and aluminum. Dravite is rich in sodium, magnesium, and aluminum. Both form in limestone that’s been altered by heat and pressure, resulting in marble that contains accessory minerals like tourmaline.

Some of the most important gem tourmalines are mixtures of dravite and uvite. They’re often brown, yellowish brown, reddish brown, or nearly black in color, but sometimes they contain traces of vanadium, chromium, or both. When present in the right concentrations, these impurities produce rich green hues that rival those of tsavorite garnet and, occasionally, even emerald. Dealers sell these gems as chrome tourmaline, even though they’re not always colored by chromium.

The bright yellow gems some dealers call “savannah” tourmalines are also mixtures of dravite and uvite. Their coloring element is iron.

Schorl is typically black, and rich in iron. It forms in a wide variety of rock types. It’s rarely used as a gem, although it has been featured in mourning jewelry.

Tourmaline’s colors have many different causes. It’s generally agreed that traces of iron, and possibly titanium, induce green and blue colors. Manganese produces reds and pinks, and possibly yellows. Some pink and yellow elbaites might owe their hues to color centers caused by radiation, which can be natural or laboratory-induced. @chapter:5


Publication Year: 2013 Title: Looking Ahead to 2014 Abstract: Welcome to the Winter 2013 Gems & Gemology. In this issue, we’re privileged to present a significant paper reviewing the current state of knowledge about diamond geology. The article’s lead author is Dr. Steven B. Shirey, a noted isotope geochemist from the Carnegie Institution of Washington and a leader in the field of inclusion-dating techniques as applied to diamond. Recent research in this area has helped date the oldest known diamonds back to 3.5 billion years—more than three-quarters the age of the earth. This article, which updates the landmark Spring 1991 G&G paper on the same topics by Melissa Kirkley et al., is co-authored by GIA’s Dr. Jim Shigley.

We hope this is the first of many articles chronicling the new frontiers of diamond research from Carnegie’s scientists. In the near future, we look to forge other active collaborations with institutions and researchers working in gem-related fields.

The Winter issue also includes excellent papers on blue sapphires from the Baw Mar area in Mogok, Myanmar; an update on gemstone mining in Luc Yen, Vietnam; and the characteristics of coated jadeite jade.

As always, we would be delighted to hear from our readers on any of the papers in this issue, or previous 2013 issues.

Now that we are on the cusp of G&Gs 80th anniversary in 2014, this is a fitting time to review some of the innovations we’ve brought to our readers during 2013. In April, we launched the Research & News section of the new GIA website and made every issue of G&G, from the current issue back to the journal’s launch in 1934, free to all users as PDF downloads at http://www.gia.edu/gems-gemology.

In the Fall issue, we introduced a new G&G article category: the field report. In upcoming issues, we aim to bring our readers more of these “direct from the mine” articles, particularly from GIA’s dedicated field gemologists, Vincent Pardieu and Andy Lucas.

With G&G now at the center of GIA’s Research & News portal, we have the opportunity to complement our articles with supporting media. In our Fall issue, we supplemented the Cheapside Hoard and Oregon sunstone papers with video interviews, image slideshows, and additional articles. This is a trend we intend to expand on in 2014. In the print version of this issue, in fact, you’ll notice a QR (quick response) code at the end of our lead article on diamond geology. This takes users with enabled smartphones and tablets directly to videos and related online content.

We also started integrating G&G into GIA’s gemology curriculum, beginning with the Diamonds & Diamond Grading course. Students can now directly access and download relevant articles via links from their eLearning course assignments. In 2014, we will extend this initiative to the remaining gemology courses.

May I take this opportunity to wish all our contributors, subscribers, reviewers, and online readers the very best for 2014.

Duncan Pay
Editor-in-Chief @chapter:29


Publication Year: 2019 Title: Emerald Update with Arthur Groom Abstract: Figure 1. Melee goods from Eternity Natural Emerald. Photo by Kevin Schumacher.

At the 2019 AGTA GemFair in Tucson, Eternity Natural Emerald (Ridgewood, New Jersey) had emeralds up to 50 ct on display. Eternity’s president, Arthur Groom, noted that the Afghanistan emerald melee sets (figure 1) had drawn the most interest. This rough melee is particularly attractive, he said, because of its higher brilliance than stones from other sources. “The Afghanistan melee is the brightest in its natural state when it’s cut properly,” he said. “Afghanistan emerald will rival Colombian any day of the week.”
Eternity has experimented with melee from different sources but finds Afghanistan melee the most plentiful and consistent. The company currently cuts Afghanistan emeralds in sizes from 1 mm to 70 ct, disproving the perception in the trade that the country produces only small emeralds. Groom pointed out that vibrant greens are not as easy to find in gems as other colors, and tsavorite is often used for green, but Eternity’s emeralds offer the option to use one of the “Big Three” gemstones. Eternity also sources emerald rough from Ethiopia, Colombia, Brazil, and Zambia.

	Emerald update with Arthur Groom

Cutting and mounting emerald melee has traditionally been challenging because of emerald’s tendency for inclusions and fractures, and its typical enhancements. Most jewelry manufacturers do not like working with it, Groom said. Eternity has solved this problem after many years of effort, he said, producing “a finely made emerald that you can work with confidence and will never change.” Eternity’s enhancement process allows the stones to be cleaned in ultrasonic and steam cleaners with no adverse effects (traditional enhancement substances tend to alter over time).

Figure 2. A set of 15 of Eternity Natural Emerald’s calibrated emeralds ranging from 1 to 5 mm. Photo by Albert Salvato.

Figure 3. A set of calibrated emeralds (approximately 2 to 4 mm each) by Eternity Natural Emerald. Photo by Kevin Schumacher.
Eternity has cut thousands of carats of rough and developed master sets of colors and clarities. They are able to fulfill orders for thousands of stones at a time. The emeralds are cut to exact proportions; the average weight retention is about 15 percent. “You can’t be concerned with how much weight you’ll lose,” Groom said. In the past, manufacturers would buy a parcel of stones of different sizes, dimensions, and colors and find some stones unusable, but they can now buy stones of the same color, clarity, and size. Along with melee, the company offers cabochons and calibrated (figures 2 and 3) and faceted stones, in qualities from commercial-grade to very fine and at all price points. Groom showed us a set of calibrated emeralds (figure 3) ideal for a premium bracelet.
One of Eternity’s aims is to promote Afghanistan emerald and country of origin. “The miner has to benefit from this,” Groom said, “and this is one of our goals in Afghanistan.” In our 2013 interview with Groom, he said Afghanistan’s emerald resources are such that if the country were to see peace, acquire investors, and mechanize its mining operations, it would “outproduce the world.”
Groom believes in promoting country of origin not because it adds value but because it adds identity to the stone. “We all know about Colombian emerald,” he said. “But just because the emerald comes from Colombia doesn’t make it more valuable. We just manufactured a 24 ct Tajik stone that sold for close to half a million dollars. You have to take the stone on its merit.” @chapter:24


Publication Year: - Title: Jeweled Butterflies Welcome Spring Abstract: The butterfly has enchanted jewelry designers for centuries because of its breathtaking beauty. There’s also another reason this “flying flower” has transfixed the imagination. The butterfly is a universal symbol of transformation.

Consider how the humble caterpillar wraps itself in a cocoon. After about ten days, the butterfly emerges, the once-earthbound dweller now free to fly from leaf to leaf.

The spectacular metamorphosis of the butterfly has long been a symbol of our potential for growth. We all strive to reach greater heights, and the butterfly speaks of our yearning to soar in the direction of our dreams.

View Gallery

Now that you know why the butterfly charms, let’s soar across the centuries and admire some of these bejeweled beauties.

Spring Eternal, an 18K yellow gold butterfly brooch by award-winning designer Paula Crevoshay, has a whimsical, dainty quality. Delicate lacework mirrors the papery wings of a real butterfly. Pink and yellow sapphires dot the butterfly’s wings, adding splashes of color. The pearl that is the body of the butterfly and the moonstone eyes evoke shimmering moonlight.

	Photo courtesy Paula Crevoshay
Buzz Gray and Bernadine Johnston, the creators of this complex brooch, are famous for selecting and cutting unusual gemstones. Their masterful handiwork and gemstone selection makes this butterfly take flight.

The vivid orange spessartine that is the body stands in sharp contrast to its delicate enamel wings, giving it a luminous glow. Black accents on the wings fall in symmetrical patterns, which are exceptionally difficult to create. These are some of the little details that make this a masterpiece.

Orange spessartine garnets from the Little Three Mine in Ramona, California, brighten this brooch, along with colorless diamonds and green tsavorite garnets from Kenya.

	Photo courtesy Buzz Gray and Bernadine Johnston
Diamond cutting methods were rudimentary when this antique piece (circa 1850) was made, but notice how the stones in the wings are graduated in size, starting as small flecks at the base and growing to larger rose-cut ones at the tips. This accomplishment would have been quite a challenge 250-plus years ago, and shows the craftsmanship of the designer.

Another nice embellishment is the scalloped edges of the wings, which give the butterfly a lifelike appearance. The brooch was probably worn with pearls or ribbons, or as a hairpiece.

	Photo courtesy Neil Lane Collection
This exquisite butterfly is particularly lifelike. Two rose-cut diamonds at the tip of the wings imitate the camouflage patterns of real butterflies.

Brilliant magenta and cobalt-blue sapphires that are the wings make for spectacular contrasts, and reveal exceptional micro-pavé work. The blackened gold antennae is a soothing counterpoint to the clash of colors.

	Gift of Dr. Gary R. and Barbara E. Hansen
A beautifully cut peridot is the body of this luminous butterfly. The asymmetrical patterns in the wings are reminiscent of Art Nouveau jewelry; the intricate metal work evokes veins.

One novel quality about this piece is that the wings are on springs (called En Tremblant), so they move with the wearer. An impressive and difficult design feat, En Tremblant makes the butterfly more than a static creation, but a piece that flutters as if it is alive.

En Tremblant was first introduced in the late 18th century in hair ornaments and became fashionable in diamond jewelry in the mid-19th century.

	Photo courtesy Buzz Gray and Bernadine Johnston @chapter:16


Publication Year: 2016 Title: Book Review: The Global Diamond Industry: Economics and Development Volume II Abstract: Edited by Roman Grynberg and Letsema Mbayi, 304 pp., Palgrave Macmillan, London, 2015, $115.00.

The Global Diamond Industry: Economics and Development Volume II is a compilation of papers that explore the shifting patterns of the diamond industry and the issues affecting southern African development. The editors are both leading academics specializing in development in the region: Grynberg a professor of economics at the University of Namibia and Mbayi a research fellow at the Botswana Institute for Development Policy Analysis.

	The first of the book’s two sections deals with the changing social aspects of the industry. Diamond manufacturing, once concentrated in a few centers (Antwerp, Gujarat, Tel Aviv, and New York), is now global and more culturally diverse, with Africans and Chinese widely engaged in the process. The opening paper, by Karin Hofmeester, offers a historical view, while the next, by Barak Richman, describes New York’s Jewish diamond community. The final paper in this section, by Sebastian Henn, describes how the industry shifted to India and then continued to diversify.

	The second, much larger section analyzes various factors of development. A paper by former De Beers chairman Nicky Oppenheimer addresses the “resource curse”—that valuable resources lead to corruption and conflict—by showing how diamonds have benefited Botswana and helped create a stable, prosperous nation. J. Andrew Grant describes the strengths and shortcomings of the Kimberley Process (misspelled “Kimberly” in the text), while Samuel Spiegel analyzes how Zimbabwe’s human rights violations at the Marange diamond deposits put the Kimberley Process into a crisis. Mbayi’s analysis of Botswana’s diamond cutting industry describes the skills transfers that are necessary to make such activities economic, and a paper by GIA’s Jim Shigley and another by Grynberg examine the challenges brought by treatments and synthetics.

	The volume, while certainly not exhaustive on any of the topics it addresses, offers a balanced cross-section of the development issues facing the diamond industry today. However, there is very little about the changing economics of the diamond industry—the multichannel rough market, competitive auctions, and the changing role of banks, to name a few—that ultimately have the greatest effect on its development. @chapter:38


Publication Year: - Title: Conference Report: ICA Congress 2013 Abstract: Participants listen to a presentation at the 2013 ICA Congress in Changsha, China. Photo by Tao Hsu.

                      On May 12–16, the International Colored Gemstone Association (ICA) held its biennial congress in Changsha, China. The theme of this congress was “Sourcing Countries and China Market.” The opening ceremony took place on May 14, and the presentations lasted through May 15.

In the opening session, Sun Fengmin from the Gems & Jewelry Trade Association of China noted the impressive growth of the Chinese economy: 7.7% during the first quarter of 2013, 4.3% of that in the consumer sector. Of the approximately US$70 billion in Chinese retail jewelry sales last year, only 1.3% was from colored stones, indicating tremendous room for growth. Several high-ranking Chinese government officials attended and addressed the Congress, including the deputy governor of Hunan, Li Youzhi. In his speech, Deputy Governor Li urged closer collaboration between the Hunan government and the province’s gem and jewelry industry. Ms. Ke Jie, director of the National Gemstone Testing Center, spoke on the role of gemological laboratories in China. Dr. Lu Taijin, chief researcher at the National Gems & Jewelry Technology Administrative Center, outlined colored stone treatments and their identification criteria in gemological laboratories. Mingxing Yang discussed the establishment of gemological education in China and the degrees currently offered.

On the second day of presentations, these contributors detailed the benefits of education from the source to the retail counter. Ken Scarratt, presenting for GIA’s Vincent Pardieu, highlighted advances in travel and communication technology that have changed how material is brought to market. New sources and the challenges of origin determination were also addressed. ICA vice president Jean-Claude Michelou called for a mechanism to trace and certify ethical sources with the UN’s Interregional Crime and Justice Research Institute. Mr. Michelou described the challenges in accomplishing this with a highly fragmented supply chain, the benefits of implementing such a system, and the risks of not doing so. Marcelo Ribeiro, director of the Belmont mine in Colombia, examined key aspects of bringing emerald to the market, including mining, sorting rough, cutting, judging cut stones, enhancements, and grading reports. Hecliton Santini Henriques, president of the Brazilian Gems and Jewelry Trade Association, gave a talk on the Brazilian gemstone and jewelry industry and how it has achieved full vertical integration. Mr. Henriques outlined the history of the Brazilian industry, the types of colored stones mined there, and the country’s role as a global supplier. Amitha Gamage and A. H. M. Imtizem of the Sri Lanka Gem and Jewellery Association reported on the island’s gem industry from mine to market. They discussed all aspects of Sri Lankan mining, including alluvial and large-scale operations and government regulations regarding mining licenses, land rehabilitation, and fair trade practices. They also spoke on advances in the cutting industry and how more trade-friendly government regulations led to a 55% increase in gem exports from 2010 to 2012.

Sophia Chong, director of the Hong Kong Trade Development Council, presented market trends. She described the effect of trade shows, trade journals, online marketplaces, mobile devices, and an integrated approach to all of these. Francis Cui, co-founder and CEO of the China Colored Stone website (www.colored-stone.com.cn) and ICA ambassador to China, discussed the use of the internet in selling at the retail and wholesale levels. Mr. Cui highlighted online shopping trends in China and how the colored gemstone industry can capitalize on them. Shirley Zhang, founder of the MeiHe Jewelry Styling Research Center, spoke about her design philosophy, which focuses on humanistic ideas and internal echoes between jewelry and the mind, as well as techniques and Chinese jewelry design. @chapter:33


Publication Year: - Title: Iolite History and Lore Abstract: Iolite has a long history of use as an adornment and possibly as a navigation tool. – Robert Weldon

                      According to legend, iolite is called the Viking Compass Stone. It’s said that thin slices of iolite served as glare-reducers and polarizing filters that helped ancient Viking navigators locate the sun on cloudy days. This allowed the Nordic mariners to pinpoint their own location on the seas.

	Whether or not it ever served as a navigation tool, iolite can be very attractive. It has long been fashioned for use in jewelry. – Robert Weldon, courtesy New Era Gems, Steve Ulatowski
The name iolite comes from the Greek word ios, meaning “violet.” Some believe that the gem aids sleep and helps to unlock creativity. Iolite is often cited as the twenty-first wedding anniversary gemstone. @chapter:25


Publication Year: 2022 Title: Natural Diamond with Extensive Network of Etch Channels Abstract: Figure 1. This 5.19 ct diamond with I color and I2 clarity displays numerous etch channels visible to the eye. Photo by Annie Haynes.
The authors recently examined a 5.19 ct type IIa natural diamond (figure 1) displaying numerous etch channels (figure 2). Etch channels are open tubes whose formation is related to dissolution processes within the stone. They form due to the dissolution of dislocations inside the crystal during or after growth and can result in various patterns; most commonly, they form as trigons or rarely as channels that appear as parallel lines, zigzags, or “worm-like” structures (T. Lu et al., “Observation of etch channels in several natural diamonds,” Diamond and Related Materials, Vol. 10, 2001, pp. 68–75, and references therein; Spring 2018 G&G Micro-World, pp. 66–67). Etch channels terminate at typically rhombic openings visible at the surface of the stone (Spring 2018 G&G Micro-World, pp. 66–67). The extensive network of etch channels in this diamond resulted in an I2 clarity grade.

Figure 2. A network of natural etch channels gives this diamond a distinctive appearance. Most of the channels have a width of ~100–150 μm, while some (e.g., lower left) show evidence of brown radiation stains. Photomicrograph by Nathan Renfro; field of view 4.69 mm.

Figure 3. Left: False-color map showing the peak area intensity of the radiation-related TR12 center (ZPL at 469.9 nm); this 455 nm PL map was compiled from 18,768 spectra collected at 45 μm pixel size. Right: The false-color map overlain with a reflected light image of the table facet. Most of the etch channels seen in the false-color map correspond with an opening observed on the table.
Photoluminescence (PL) mapping using 455 and 532 nm laser excitation (figures 3 and 4) revealed an increase in the GR1, 3H, and TR12 centers along the walls of the etch channels; all of these centers are defects associated with radiation exposure. The nitrogen vacancy centers NV0 (zero-phonon line [ZPL] at 575 nm) and NV– (ZPL at 637 nm) were also concentrated along these channels. The concentration of these defects along the etch channels suggests that radioactive fluids once flowed through the tubes. The radioactive fluids had an impact on the areas in direct contact, creating elevated concentrations of radiation-related peaks. Other prominent PL peaks along the cavities were centered at 474, 598.75, and 461.5 nm. The radiation in these fluids would have been low enough to not create much observable staining, as patches of green to brown color associated with radiation staining were not observed in most of the etch channels. However, there were some isolated spots of green radiation stains and some channels with a brownish appearance (figure 2) and elevated concentrations of radiation-related features (figures 3 and 4). Additionally, the exposure to radioactive fluids must have occurred after the diamond was brought to the near-surface region following kimberlite eruption, as these radiation-related features would not withstand the high temperatures within the mantle.

Figure 4. GR1/Raman peak area ratios calculated from the 532 nm PL map (inset) cutting across multiple channels along the orange line. Higher GR1/Raman areas are concentrated along the etch channels.
Similar radiation features have previously been observed in another stone with cavities (Spring 2020 Lab Notes, pp. 126–127), but to a much lesser degree. The extensive network of etch channels within this diamond is one more example of the extraordinary possibilities within the natural world. @chapter:11


Publication Year: - Title: Fancy Color Diamond Care and Cleaning Guide Abstract: With proper care Fancy color diamonds can also be "forever". - Robert Weldon

Hardness
Gem and mineral hardness is measured on the Mohs scale. The scale originated in 1822 when Friedrich Mohs chose ten minerals and assigned numbers to them, based on the relative ease or difficulty with which one could 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. Only a diamond can scratch a diamond.

Something the Mohs scale doesn’t show, but that’s equally important to the diamond industry, is that diamond can also scratch any of the precious metals used for settings. That means a diamond that’s loose in its setting can wear through a prong over time.

	Diamond rates highest on the Mohs hardness scale, at number 10.

Toughness
Any stone, including a diamond, will fracture if it’s hit hard enough in the right place. Toughness is a measure of how well a gem can survive an impact and resist breaking, chipping, or cracking.

Diamonds are tougher in the directions where the atoms are bonded tightly together, less tough where they’re not so tightly bonded.

The weakest directions are the ones where the atoms are farthest apart. It’s easier to break a diamond in those directions, which are called cleavage directions. A cutter can split a rough diamond by hitting it sharply in the cleavage direction. Even after cutting, a hard blow can still cleave or fracture a diamond. This can happen during the setting process, when it’s being worn, or when it accidentally strikes another object.

Stability
Stability is a term that describes how well a diamond resists temperature changes and chemicals. Diamonds are very stable. They’re invulnerable to virtually all acids, for one thing. The cutting process generates a lot of heat, but diamonds usually endure intact. Situations that are more threatening to a diamond’s stability are those that involve sudden and extreme temperature changes. Those changes can cause thermal shock and create new fractures and cleavages or cause existing ones to spread.

Diamonds will burn at about 1562°F (850°C). House fires and jewelers’ torches can reach that temperature. During jewelry repair, the bench jeweler can use certain methods to protect the diamond from the torch’s high-temperature flame.

Cleaning
Diamonds can be safely cleaned with lint-free cloths, commercial jewelry cleaning solutions, and household detergents.

Harsher cleaning methods are not recommended for household use. These include powdered abrasive household cleansers, ultrasonic cleaners, and steam cleaners. @chapter:31


Publication Year: 2005 Title: Characterization of the New Malossi Hydrothermal Synthetic Emerald Abstract: A new production of hydrothermal synthetic emeralds, grown in the Czech Republic with Italian technology, has been marketed since December 2004 with the trade name Malossi synthetic emerald. Several samples were investigated by standard gemological methods, combined with chemical analyses and UV-Vis-NIR and IR spectroscopy. A comparison of this material with natural and other synthetic emeralds (the latter grown by the flux and hydrothermal techniques) reveals that Malossi hydrothermal synthetic emerald can be identified on the basis of  microscopic features and chemical composition, along with the mid-infrared spectrum. @chapter:9


Publication Year: 2017 Title: Cosalite in Quartz Abstract: Figure 1. This 16.20 ct quartz contains an abundance of inclusions. Photo by Kevin Schumacher.

A search of the gemological literature shows that rock crystal quartz contains a wide variety of unusual and interesting inclusions. Many of those inclusions look alike, so careful analysis is necessary for a positive identification. We recently examined a 16.20 ct cushion-shaped rectangular modified step-cut rock crystal from Kara-Oba, Betpaqdala Plateau, Kazakhstan (figure 1), that was fashioned by Michael E. Gray (Coast-to-Coast Rare Stones, Mendocino, California). Measuring 18.15 × 13.24 × 10.60 mm, it hosted several opaque silvery gray stalks and needles that appeared to have an orthorhombic morphology (figure 2). A fragment cut from the original rough crystal was analyzed by laser Raman microspectrometry and yielded a possible identification as cosalite, a rare orthorhombic lead bismuth sulfide. This was subsequently confirmed by X-ray powder diffraction. The discovery of such a rare mineral as an inclusion in this stone was a pleasant surprise.

Figure 2. Displaying an orthorhombic morphology, these inclusions were identified as cosalite. Photomicrograph by Nathan Renfro; field of view 4.11 mm. @chapter:13


Publication Year: 2023 Title: Brenda Smith Jewelry Designs Abstract: Figure 1. A: This Lace Ring is crafted in 18K rose gold with blackened gold lace, featuring a cultured freshwater pearl measuring 16.5 mm in diameter, enclosed by natural-color pink and lavender sapphire round brilliants weighing 2.86 carats total. The shank of the ring is embellished with 0.06 carats of diamonds. B: This Tahitian pearl Lace Ring is created in 18K white gold with sandblasted and blackened gold lace. The cultured Tahitian pearl measures 16.0 mm and is surrounded by round brilliant diamonds, 1.35 carats total. The rubies in the shank weigh a total of 0.08 carats. C: A handmade doily crocheted by Smith’s grandmother. Photos courtesy of Brenda Smith.
Brenda Smith Jewelry has earned four AGTA Spectrum Awards to date for design excellence. At this year’s AGTA designer showroom, Smith presented three masterpieces to the authors: two award-winning rings featuring pearl and blackened gold lace and an opulent pair of earrings featuring millefiori faces.
Smith’s most prized creation is her Lace Ring design. She shared her white Lace Ring featuring a large cultured pearl accented with gold lace, sapphires, and diamonds (figure 1A), followed by a black Tahitian pearl Lace Ring with blackened gold lace, rubies, and diamonds (figure 1B). Inspired by her grandmother’s handmade crocheted doily featuring a pineapple motif (figure 1C), the rings were created as a tribute to her memory. In 2021, the white freshwater pearl ring won Best Use of Pearls in the AGTA Spectrum competition and the Tahitian pearl ring won the InDesign Award in the category of Pearl Jewelry Over $5,000.

Figure 2. These “Gibson Girl” millefiori earrings in 18K white gold contain Paraíba tourmalines (1.11 carats total), pink tourmalines (1.54 carats total), and 0.56 carats of aquamarine. Photo courtesy of Brenda Smith.
Smith’s one-of-a-kind “Gibson Girl” earrings (figure 2) are inspired by the Austrian symbolist painter Gustav Klimt. Klimt’s paintings combined realistic faces with geometric clothing, and Smith mirrored this style to create this high-end piece of jewelry. The technique used to create the girl faces is millefiori, which means “thousand flowers” in Italian and produces slices from canes with concentric and colorful patterns. Millefiori techniques can be used to make jewelry, decorative objects, candy, and art pieces. Creating these objects requires a skilled artisan who possesses a deep understanding of material properties, considerable experience, and patience. American artist Barbara McGuire handcrafted the complex face canes for the earrings by arranging and embellishing polymer clays to create a lifelike image. Though millefiori objects are commonly used in decorative pieces, Smith’s design incorporates a harmonious blend of colored gemstones expertly paired and crafted to create a lively figure with a unique personality and color scheme, making it an extravagant and elegant piece of jewelry. @chapter:16


Publication Year: 2016 Title: Exhibition Review: Lustre: Pearling and Australia Abstract: Figure 1. Pearls scattered over an oyster shell. Photo courtesy of Cygnet Bay Pearls.

	Australia’s pearling history reaches back more than 20,000 years, far longer perhaps than many would expect. The exhibition Lustre: Pearling and Australia (figure 1) at the Immigration Museum in Melbourne details how the lustrous shells and pearls have been objects of passion not only as key items in indigenous rituals and mythology, but also as prized objects in the quest for economic wealth since the 1800s. In a well-balanced mix of exhibits, multimedia, and interactive presentations, the exhibition tells the Australian history of pearling, drawing on Aboriginal, Asian, and European stories from its beginnings until today.

Figure 2. Strickland Bay, Western Australia, roughly 150 km north of Broome, was a traditional area for collecting pearl shell. Photo courtesy of Aubrey Tigan, Mayala elder.

	Long before contact with Europeans, Aboriginal people harvested and carved pearl shell and traded it inland from the coast (figure 2). Indigenous coastal people still use pearl shell as a “canvas,” engraving the lustrous shells with designs sometimes highlighted with ochre. Worn exclusively by men, these artworks are thought of as a manifestation of water and life and were traded over vast distances across Australia. A 22,000-year-old piece of shell found in a West Kimberley rock shelter, 200 km from the shoreline, is the oldest known. Contemporary pearl shell carving tells the story of the country, and the works of Kimberley coastal artists can be found in collections around the world (figure 3).

Figure 3. Carved shell depicting the shell beds on the Lacepede Islands off Australia’s northwest coast, 120 km from Broome. Photo courtesy of Aubrey Tigan Galiwa, Mayala elder.

	The 1850s saw the birth of the Australian pearling industry in Western Australia, where Pinctada albina mussels were first collected by entrepreneurs at Shark Bay. After Shark Bay was stripped of its mussel populations, the 1861 discovery of the much larger P. maxima shells farther north at Nickol Bay attracted greater numbers of prospective pearlers. By 1870 an industry had been established in the Torres Strait in Australia’s far northeast. Eventually the pearling industry moved to Broome in the West Kimberley, which by 1910 was the largest pearling center in the world (figure 4). Hosting a large fraction of Japanese and Chinese pearlers, it was fueled by a booming international pearl button market.

	The breakthrough of culturing round pearls in Japan in 1916, when the first cultured pearls were marketed by Kokichi Mikimoto, resulted in an attempt to establish an Australian cultured pearl farm in 1921. However, lobbying against it by other pearlers resulted in the prohibition of pearl culturing in West Australia. The ban was not lifted until 1949.

	Divers were almost exclusively of Asian and Aboriginal descent, and Japanese divers were reputedly the best. The colonial history was harsh and marked by the exploitation and segregation of the laborers. They made up most of the tight-knit crews on “pearling luggers”—ketch-rigged wooden vessels 13 to 19 meters in length—and set out for seabeds as “saltwater cowboys” in search of pearl shells.

Figure 4. The crew of a pearl lugger in Broome, ca. 1900–20. Photo courtesy of the National Archives of Australia.

	Pearling ceased in 1941 when local Japanese were interned during World War II. After the war, beginning in 1956, Australian pearl farming was reinvented in the form of cultured South Sea pearl farms, with new technologies, safer practices, and a better understanding of mussel sustainability. The modern manufacture and sale of South Sea pearls has little to do with the saltwater cowboys who stripped the seabeds in historical times. New standards in hygiene and maintenance of mussels have been introduced, as well as new vessels designed as “floating laboratories” that allow operating on the mussels in their natural habitat. A shift from collecting large pearl shells to cultivating pearls using small shells has eased the pressure on populations in the wild.

	Along with the history of Australia’s pearling heritage, the exhibition also touches on more generic topics, such as the nature of the material “pearl,” pearling techniques, and the zoology of P. maxima, the pearl mollusk.

	For those who cannot visit the exhibition, the museum offers online resources, such as images and text panels from the exhibition, accessible at http://museum.wa.gov.au/explore/lustre-online-text-panels.

Lustre: Pearling and Australia, curated in a partnership between the Western Australian Museum and Nyamba Buru Yawuru, is showing at the Immigration Museum, Melbourne, Australia, until January 15, 2017. Admission is 14 AUD for adults; children are free. The museum is open daily from 10 am to 5 pm (closed Good Friday and Christmas Day). @chapter:21


Publication Year: 2016 Title: Sapphire Rough Filled with Green Lead Glass Abstract: Figure 1. This hexagonal green sapphire rough was treated with a green lead-glass filling. Right: Green residue and trapped gas bubbles are seen in the filled fractures; field of view 2.90 mm. Photos by Jonathan Muyal.

	The Carlsbad laboratory recently examined a yellow-green hexagonal prismatic crystal (figure 1, left) that was presented as sapphire. The rough specimen was approximately 11 mm long. The specific gravity was measured as 4.00, and the stone was inert to both long- and short-wave UV. The identity of the rough sapphire was confirmed by Raman spectroscopy. Microscopic examination revealed that the stone was partially covered by drops of green glassy residue, and numerous fractures throughout it were filled with the same material. Also observed were numerous trapped gas bubbles and a prominent orange flash effect, consistent with a lead-glass filling (figure 1, right). Energy-dispersive X-ray fluorescence (EDXRF) analysis confirmed the presence of lead.

	Laser ablation–inductively coupled plasma–quadrupole mass spectrometry (LA-ICP-MS) was used to investigate the chemical composition of the green glassy residue. A line of ablation spots, positioned on one of the flat crystal faces, was designed to cross a large drop of the residue. The oxide weight percent profile (figure 2, left) revealed that the residue contained 9.3 to 9.7 wt.% B2O3, 23.7 to 24.9 wt.% Al2O3, 12.2 to 12.6 wt.% SiO2, 3.6 to 4.2 wt.% CuO, 1.2 to 1.3 wt.% CdO, and 45.4 to 47.4 wt.% PbO. The combined oxide weight percent of Li, Na, K, Ca, and Zr was around 1.5 (averaged value). The chemical analysis confirmed that the filler was lead glass.

	Figure 2. Left: The wt.% oxide profile shows a strong correlation between the glassy residue and a high Pb concentration. Right: The lead glass shows a refractive index of 1.75 for a PbO content of 63.3 wt.%. Inset photo by Jonathan Muyal.

	With such a small amount of Al (2.6 wt.% Al2O3) in the lead glass (Z.Q. Zeng and P. Hing, “Preparation and thermal expansion behavior of glass coatings for electronic applications,” Material Chemistry and Physics, Vol. 75, No. 1–3, 2002, pp. 260–264), the approximate composition of major elements can be obtained by subtracting 24.22 wt.% Al2O3 (arising from the host sapphire crystal) from the total chemical composition and renormalizing the sum to 100 wt.% oxide (R. Barbour, Glassblowing for Laboratory Technicians, Wellington, New Zealand, Pergamon Press, 1978, p. 4). The renormalized composition of the lead glass was 63.3 wt.% PbO, 16.9 wt.% SiO2, 12.8 wt.% B2O3, 5.3 wt.% CuO, and 1.7 wt.% CdO. The PbO wt.% was plotted on the Pb wt.% oxide vs. refractive index plot (http://physics.info/refraction) and showed an RI of 1.75, which is very close to corundum’s RI of 1.76–1.77 (figure 2, right). The high refractive index of the glass concealed the difference in luster between corundum and filler.

	A previous study reported on blue cobalt-colored lead glass–filled sapphires whose color was assigned to the presence of a small amount of cobalt in the filler (T. Leeawatanasuk et al., “Cobalt-doped glass-filled sapphire; an update,” Australian Gemmologist, Vol. 25, No. 1, 2013, pp. 14–20). The green color of the glass in this specimen was likely caused by the combination of CuO (which causes a greenish blue color in glass) and CdS (which causes a yellow color; see B.H.W.S. De Jong et al., “Glass,” in Ullmann’s Encyclopedia of Industrial Chemistry, Wiley-VCH, 2000, http://dx.doi.org/10.1002/14356007.a12_365). The yellowish appearance and the high levels of Fe (1629 to 2640 ppmw) in the area without filler indicate that the piece might have been a yellow sapphire before being filled. This was the first sapphire with green lead-glass filling examined at the Carlsbad laboratory. @chapter:12


Publication Year: 2016 Title: Kämmererite Cabochons from India Abstract: Figure 1. This 57 mm wide kämmererite rough and 0.57 ct faceted stone are from the Kop Daglari Mountains of Turkey. Photo by Jaroslav Hyršl.

Kämmererite is a purple variety of clinochlore, a mica-like Mg-Al-silicate with the formula (Mg,Fe)5Al[(OH)8|AlSi3O10]. Its color is caused by chromium. Kämmererite is always found in fractures of ultrabasic rocks, usually with chromite ore. The only known locality for transparent crystals is the Kop Krom chromite mine in the Kop Daglari Mountains of Turkey. Transparent crystals from this area (figure 1) can measure up to 2 cm. Some of this material has been faceted as rare collector gemstones (H. Bank and H. Rodewald, “Schleifwürdiger, roter, durchsichtiger Chlorit: Kämmererit,” Zeitschrift der Deutschen Gemmologischen Gesellschaft, Vol. 28, No. 1, 1979, 39–40, in German).

An unknown location in India recently yielded massive kämmererite that was used to carve interesting cabochons (figure 2); 10 such samples were examined in this study. The cabochons have an attractive light to dark purple color; some thinner pieces are translucent. Some of the material shows a folded texture, and this type is visually similar to charoite, a well-known ornamental stone from Siberia. The measured refractive index (RI) of the new kämmererite is approximately 1.57, very close to charoite, but clinochlore has a much lower Mohs hardness (about 2.5, rather than charoite’s 5–6). This new kämmererite is inert under UV light, but white layers in the samples show creamy fluorescence under both long-wave and short-wave UV. Raman spectroscopy revealed a characteristic group of peaks at 3877, 4063, 4175, 4500, and 4920 cm–1 in the spectrum (figure 3), confirming the material’s identity. Visible spectra further supported this conclusion. The amount of new massive kämmererite rough is unknown, and the material may remain rare.

Figure 2. These kämmererite cabochons, with widths of 27 mm and 21 mm, are from an undisclosed location in India. Photo by Jaroslav Hyršl.

Figure 3. Raman spectra showing characteristic peaks of kämmererite at 3877, 4063,
4175, 4500, and 4920 cm–1. @chapter:13


Publication Year: 2022 Title: Garnet with Apatite Inclusions Abstract: Figure 1. Left: This 3.07 ct purplish pink “dragon” garnet, as seen in daylight-equivalent lighting, displays eye-visible blue apatite inclusions. Right: Red fluorescence in the garnet due to chromium, as seen using long-wave UV. Photos by Jessa Rizzo; courtesy of Ravenstein Gem Co.

Figure 2. Blue apatite inclusions and rutile needles were prominent throughout the “dragon” garnet reportedly from a new find in Africa. Photomicrograph by Nathan Renfro; field of view 2.40 mm.
The authors recently examined a 3.07 ct garnet sample acquired from Ravenstein Gem Co. by author NR. This gem material, marketed online as “dragon” garnet as an allusion to the mythical creature’s changing eye color, was reportedly from a new find at an undisclosed locality in Africa. It is also notable that Lotus Gemology has reported similar material from Tanzania (Summer 2022 G&G Micro-World, pp. 226–227). The garnet was a delicate purplish pink color under daylight-equivalent lighting (figure 1, left) and showed a fairly strong red fluorescence when exposed to long-wave ultraviolet light (figure 1, right). Also of note, this sample, as well as many of the other examples showcased online, contained vibrant blue inclusions of apatite (figure 2) as well as typical needle-like silk and minute fluid inclusions.

Figure 3. The garnet’s UV-Vis-NIR spectrum suggests the color results mainly from manganese, iron, chromium, and vanadium. Narrow bands at 409, 422, and 430 nm are related to manganese in the garnet structure, while absorption bands related to iron are at ~465 and 488 nm (Z. Sun et al., “Quantitative definition of strength of chromophores in gemstones and the impact on color change in pyralspite garnets,” Color Research and Application, Vol. 47, 2022, pp. 1134–1154). A broad band centered at ~572 nm is from vanadium and chromium absorption.

Figure 4. The photoluminescence spectrum collected from the garnet using a 514 nm laser revealed chromium-related emission consistent with the observed red fluorescence under long-wave UV excitation.
Gemological testing revealed a refractive index measurement of 1.741 and a hydrostatic specific gravity of 3.81. Further gemological testing with laser ablation–inductively coupled plasma–mass spectrometry revealed the major composition to be pyrope (61.5 mol.%), spessartine (29.0 mol.%), grossular (6.5 mol.%), and almandine (2.6 mol.%), a chemistry consistent with pyralspite-series garnets. Notable trace elements in significant quantities were chromium (660 ppmw) and vanadium (343 ppmw) in addition to the rare earth elements yttrium (1206 ppmw), erbium (222 ppmw), and ytterbium (420 ppmw). The ultraviolet/visible/near-infrared (UV-Vis-NIR) spectrum revealed absorption bands that were consistent with the chemical analysis (figure 3), indicating that the color of the garnet results from a mixture of manganese, iron, chromium, and vanadium. Raman analysis confirmed the blue inclusions as apatite. It is also notable that the garnet sample showed a weak color change in daylight compared to various non-standardized, commercially available LED types of lighting, changing from purplish pink to pink-orange. Photoluminescence testing with a 514 nm laser revealed a strong chromium-related emission, consistent with the red fluorescence observed with long-wave UV exposure (figure 4).
The strong red fluorescence, color change under certain LED lights, and presence of significant rare earth elements and vibrant blue apatite inclusions make it quite interesting for any gem collector. @chapter:13


Publication Year: 2023 Title: The history of gemstones in Chanthaburi_19 Abstract: In the past, the gemstone mines of Pailin in present-day Cambodia were already known locally before falling under Siamese rule. However, their recognition increased significantly in terms of mining and trade around the year 2425 (1882 CE). Gula(Kula) people from Shan State also entered to work in the gemstone industry in Pailin during this period. @chapter:25


Publication Year: 2014 Title: Geo-Literary Society Meeting Abstract: The Geo-Literary Society held its annual meeting on Feb. 14 at the Tucson Convention Center. The event, which drew attendees from the Tucson Gem and Mineral Shows, featured presentations by Scott Sucher and Al Gilbertson in a session titled “The Evolution of Diamond Cutting.”
Sucher, president of The Stonecutter in Albuquerque, New Mexico, has created replicas of famous diamonds for more than 30 years. Gilbertson, a research associate at GIA in Carlsbad, California, has authored numerous articles on diamond cut and grading, as well as the 2007 book American Cut: The First 100 Years.
Sucher opened the session by chronicling the early history of diamond use, global trade patterns, and advances in cutting techniques and styles. Using computer models, he compared the brilliance and fire of several early diamond cuts.
Gilbertson picked up the story with the discovery of Brazilian diamond deposits around 1725, which ushered in a period of glittery excess among European elites. David Jeffries, whose 1750 treatise described the use of a handheld “prover” to measure cutting angles, coined the term “round brilliant” for a cut that contained 58 facets.
The discovery of massive diamond deposits in South Africa in 1867 changed the course of the industry, making these treasures available to a mass market. By 1870, there were 10,000 cutters in Europe. These artisans followed the shape of the original crystal and kept as much of the original weight as possible.
But the emphasis on weight retention was beginning to unravel thanks to Henry Morse, who set up a cutting shop in Boston around 1860. Morse, who once said, “Shopping for diamonds by the carat is like buying a racehorse by the pound,” emphasized the cut of a stone and the brilliance that resulted. He invented a gauge to measure crown and pavilion angles, and devised his own set of best proportions. He also helped develop mechanical bruting, which increased the production of round-cut diamonds.
With turn-of-the-century improvements such as the circular saw, which made it easy to cut two diamonds from a rough crystal, the stage was set for the modern round brilliant. In 1919, Belgian engineer Marcel Tolkowsky published a landmark book, titled Diamond Design, in which he asserted that the best-cut stones feature a 53% table, 59% total depth, and a knife-edged girdle. With some modifications to Tolkowsky’s proportions—an extended lower half, a larger table, and a closed-up culet—the round brilliant as we know it was established by 1950.
As Gilbertson pointed out, the breakthroughs in diamond cut planning and evaluation were just beginning. The Firescope viewer, developed in 1986, allowed the user to see a “Hearts and Arrows” pattern in a diamond cut to these “ideal” proportions. The Sarin scanner, introduced six years later, offered rapid, accurate proportion measurement, which led to the various cut grading services available today. Among other recent advances are inclusion-mapping software and high-speed laser cutting.
Following the presentation, Sucher invited the audience to view his faceted replicas of Cullinans I and II, the Koh-i-Noor, the Hope, and several other historical diamonds.
“Scott Sucher transported us to the early days of diamond cutting as we learned the first sources and tools,” said Dona Dirlam, the Geo-Literary Society’s secretary and the host of the session. “We saw how cutting styles evolved with improvements in the tools and an increase in the diamond supply. With each development, we saw this fascinating transformation through visual models.
“Al Gilbertson told us the largely unknown story of Henry Morse and chronicled the birth of the modern round brilliant,” Dirlam added. “As Al and Scott pointed out, today’s computer-optimized diamond cutting seems light-years removed from the earliest techniques.” @chapter:24


Publication Year: 2021 Title: Unusual Composite Apatite-CO2 Inclusions in Sapphires from Ohn Bin Yee Htwet, Myanmar Abstract: Figure 1. Composite apatite/CO2 inclusion in a sapphire from Ohn Bin Yee Htwet. Photomicrograph by Aaron Palke; field of view 1.99 mm.

Routine investigation of a parcel of sapphires from Ohn Bin Yee Htwet near Mogok in Myanmar revealed something unexpected. Unusual composite inclusions were observed where one part of the inclusion exhibited flat, crisp, angular planes, while the other part showed an irregular and rough surface (figure 1). Raman spectroscopy identified the two phases as apatite (the flat, crystalline-looking area) and CO2 (the rough and irregular surface).

Figure 2. A myriad of inclusions at the boundary between the dense, silky core and the unincluded rim. Photomicrograph by Jonathan Muyal; field of view 1.76 mm.
The rough and irregular part of the inclusion also showed a gas bubble within the fluid CO2, which disappeared when warmed in the well light of the microscope as the gas and liquid homogenized. These inclusions generally sit atop a dense nest of rutile silk. The rutile silk is tightly clustered in the core of the sapphire crystals and terminates rather abruptly. A myriad of inclusions is often found at the boundary between the dense, silky core and the unincluded rim (figure 2).
While both apatite and CO2 are routinely observed in sapphires from a variety of sources, finding both phases in a single inclusion is unexpected and has not been previously reported, to the author’s knowledge. It is hypothesized that these inclusions formed when apatite was trapped within the sapphire and created a growth blockage, thus allowing the fluid present (CO2) to adhere to the surface of the apatite and sapphire to become included as well. @chapter:19


Publication Year: 2020 Title: Bismuth Glass-Filled Burmese Star Ruby Abstract: Figure 1. A 5.35 ct purplish red cabochon displaying asterism. Photo by Johnny Leung.

The Hong Kong laboratory recently examined a 5.35 ct purplish red oval cabochon displaying asterism (figure 1). Standard gemological tests yielded a spot refractive index (RI) of 1.76, medium red fluorescence under long-wave ultraviolet (UV) light, weak red fluorescence under short-wave UV, and a diagnostic spectrum in the handheld spectroscope, all of which were consistent with ruby.

Figure 2. Left: Blue flashes and trapped gas bubbles of various sizes and shapes along surface-reaching fractures and cavities. Photomicrograph by Xiaodan Jia; field of view 7.64 mm. Right: The bismuth glass-filled fractures and cavities were easily visible in the X-ray image. Image by Sze Ling Wong.
Magnification revealed iridescent silk and arrowhead-like inclusions similar to those frequently found in Burmese rubies. Apart from the natural inclusions, easily observable foreign substances for clarity enhancement were found along surface-reaching fractures and cavities. Numerous rounded to flattened gas bubbles and blue flashes were visible within filled fractures (figure 2, left). The filler also exhibited a different luster from that of the ruby under reflected light. X-ray radiography indicated heavy element depositions along these fractures and cavities (figure 2, right). The Fourier-transform infrared (FTIR) spectrum showed two broad absorptions centered at 3500 and 2670 cm–1 associated with manufactured glass. Qualitative analysis using energy-dispersive X-ray fluorescence (EDXRF) spectroscopy revealed the presence of bismuth, whereas no lead was detected. This confirmed that the foreign material was actually a bismuth-based glass.
Based on internal features and advanced testing results, the stone was positively identified as a manufactured product consisting of bismuth glass and ruby. Although bismuth-based glass has occasionally been applied to corundum as a filling material (Spring 2017 Lab Notes, p. 94), it is rare to detect it in star ruby. @chapter:12


Publication Year: 2013 Title: Copper-Bearing Minerals of Colorado Abstract: Between 1868 and 1922, Colorado produced almost 260 million pounds of copper. Nearly 100 million pounds came from the Leadville district, with another 50 million mined in San Juan County. During the 20th century, the Gilman district surpassed Leadville in total copper production, yielding more than 210 million pounds. Total Colorado production prior to 1958 reached 585 million pounds.

In this article, 106 minerals from the Colorado Mineral Belt (COMB) are listed and 39 are discussed in the text. The Eagle mine in the Gilman district is probably Colorado’s most prolific producer of mineral specimens. Gilman pyrite, sphalerite, chalcopyrite, siderite, barite, and galena are found in collections all around the world. The Sweet Home mine in Buckskin Gulch, a source of world-famous rhodochrosite, is also well known for fine specimens of two copper-bearing minerals, bornite and tetrahedrite. The Creede mining district is one of the most extensively studied mineral deposits and volcanic areas in the country. A detailed study of the Creede ore deposits has been conducted in an attempt to develop a model for epigenetic precious-metal deposits. Summitville is well known as the source of the state’s finest covellite specimens. The Good Hope mine is the type locality for four copper-bearing tellurides: rickardite (Cu3-xTe2), weissite (Cu2-xTe), vulcanite (CuTe), and cameronite (AgCu7Te10). Turquoise was mined from the King mine deposit in Conejos County and from the Chief mine in the St. Kevin district of Lake County.

The state of Colorado has produced some significant copper-bearing mineral specimens. Most of its copper minerals are sulfides and sulfosalts, with chalcopyrite the most common copper-bearing mineral.

Abstracted by Guy Lalous @chapter:7


Publication Year: 2012 Title: Detecting HPHT Synthetic Diamond Using a Handheld Magnet Abstract: This study investigated the effectiveness of a handheld magnet in detecting synthetic diamonds. A total of 104 synthetic diamonds from nine different manufacturing sources were tested. Of the HPHT-grown synthetic samples tested, 58% registered a detectable magnetic response. Strong N52-grade neodymium magnets were able to detect 35% more HPHT synthetics than traditional ferrite and alnico magnets. CVD-grown synthetic diamonds showed no magnetic attraction. A set of 168 natural diamonds, including HPHT-treated natural diamonds, was tested as a control group. None of the natural transparent diamond samples showed attraction to a neodymium magnet, but two heavily included translucent specimens with unusually large opaque inclusions were strongly magnetic. A new magnetic testing method is presented for detecting small magnetic inclusions in loose HPHT-grown products, and for identifying small synthetic diamonds mounted in jewelry. @chapter:15


Publication Year: - Title: Pearl Description Abstract: Cultured pearls come in different sizes, shapes, and colors.

Perhaps the best-loved gems of all time, pearls—both natural and modern cultured pearls—occur in a wide variety of colors. The most familiar colors are white and cream (a light yellowish brown). Black, gray, and silver are also fairly common, but the palette of pearl colors extends to every hue. The main color, or bodycolor, is often modified by additional colors called overtones, which are typically pink (sometimes called rosé), green, purple, or blue. Some pearls also show the iridescent phenomenon known as orient.

This newly opened akoya pearl oyster reveals the cultured pearl that grew inside its gonad. This oyster’s scientific name is pinctada fucata (martensii).
Cultured pearls are popular for bead necklaces and bracelets, or mounted in solitaires, pairs, or clusters for use in earrings, rings, and pendants. Larger pearls with unusual shapes are popular with creative jewelry designers.

This multicolored necklace combines the beauty of Tahitian and South Sea cultured pearls. The scientific names of the oysters that produced them are, respectively, Pinctada margaritifera and Pinctada maxima. - Courtesy Frank Mastoloni & Sons, Inc.
Pearl—natural or cultured—is a US birthstone for June, together with alexandrite and moonstone.
Natural Pearls vs. Cultured Pearls
Natural Pearls
Natural pearls form in the bodies, or mantle tissue, of certain mollusks, usually around a microscopic irritant, and always without human help of any kind.
Cultured Pearls
The growth of cultured pearls requires human intervention and care. Today, most of the mollusks used in the culturing process are raised specifically for that purpose, although some wild mollusks are still collected and used.

This group of cultured pearls displays some of the exotic colors pearls can exhibit. - Blaire Beavers, courtesy Takayas Mizuno
To begin the process, a skilled technician takes mantle tissue from a sacrificed mollusk of the same species and inserts a shell bead along with a small piece of mantle tissue into a host mollusk’s gonad, or several pieces of mantle tissue without beads into a host mollusk’s mantle. If a bead is used, the mantle tissue grows and forms a sac around it and secretes nacre inward and onto the bead to eventually form a cultured pearl. If no bead is used, nacre forms around the individual implanted mantle tissue pieces. Workers tend the mollusks until the cultured pearls are harvested.
Pearl Types
There are four major types of cultured whole pearls:
Akoya Cultured Pearls
Akoya cultured pearls are the most familiar type of saltwater cultured pearl to most people in the U.S and other western markets. Many customers think of white or cream colored akoyas as the classic pearl used for jewelry, especially single-strand necklaces. Japan and China both produce akoya cultured pearls.
South Sea Cultured Pearls
Australia, Indonesia, and the Philippines are leading sources of these saltwater cultured pearls. South Sea cultured pearls can be white to silver or golden, depending on the type of oyster. Their large size and thick nacre, due to a long growth period, plus their limited critical growing conditions are all factors contributing to their value.
Tahitian Cultured Pearls
Cultivated primarily around the islands of French Polynesia (the most familiar of these is Tahiti). These saltwater cultured pearls, sometimes referred to as black pearls, have a wide color range. They might be gray, black or brown, and they can have blue, green, purple or pink overtones.
Freshwater Cultured Pearls
Freshwater cultured pearls are the most commonly produced pearls and they are one of the most popular pearl types among shoppers and jewelry designers. This is due to their remarkable range of sizes, shapes and colors, plus their commercial availability at lower price points. They are usually cultured in freshwater lakes and ponds, often with many pearls grown in one oyster. China is the leading source for freshwater cultured pearls.

Cultured pearls from Australia, Indonesia, the Philippines, and Myanmar, are grown in the Pinctada Maxima mollusk. This shell one is called gold-lipped because of the color of the outer rim of its mother-of-pearl layer.

The black-lipped mollusk can produce a variety of cultured pearl colors. The color of the mother-of-pearl layer is often related to the color of the resulting cultured pearl’s nacre. - Courtesy A & Z Pearls and Tasaki Shinju Co @chapter:14


Publication Year: - Title: And Then Came the Fantasy Cut Abstract: View Gallery

	Once upon a time, gem cutting was a strict craft bound by centuries of tradition. The job of a lapidary was to cut a gemstone to ideal proportions while preserving as many carats as possible. Then Bernd Munsteiner (b. 1943) invented the fantasy cut (concave cuts made on the back of gemstones).

	Munsteiner freely sliced away carats on the backs of gemstones to create spectacular lightshows on their fronts. The only ideal proportion he acknowledged was the one that freed the natural beauty he saw hiding in the stone.

	Many in the gem and jewelry trade didn’t know what to make of the fantasy cut. But the critics eventually became admirers, and Munsteiner’s pieces ended up in galleries and museums.

	Munsteiner’s most famous work may be the Dom Pedro – Ondas Maritimas, an exquisite 10,363 ct aquamarine gemstone. It is so breathtaking that the Smithsonian said it is “one of the few objects in the world that can hold its own in a display case just 30 feet from the Hope Diamond.”

	Munsteiner’s Dom Pedro – Ondas Maritimas, 1993, was a watershed creation: it signaled that the fantasy cut had become an accepted art form. Photo by Donald E. Hurlbert, courtesy of the Natural History Museum, the Smithsonian Institute

	Munsteiner’s innovative work inspired generations of award-winning lapidaries like Richard Homer, Michael Dyber, John Dyer, and Sherris Cottier Shank. The American Gem Trade Association even hosts the prestigious Cutting Edge Awards competitions where lapidaries submit fantasy cut gemstones.

	Richard P. Homer, GIA GG, won a 2013 AGTA Spectrum Award for his 36.74 ct Antique Cushion Concave Focus™ cut Imperial Topaz. Photo by Robert Weldon, courtesy of Gems By Design, Inc., Kent, OH

	Sherris Cottier Shank created the swirls in this spectacular 8.97 ct pink tourmaline by making curved grooves on the pavilion. Photo by Sherris Cottier Shank

	One of the most significant differences between fantasy cuts and traditional cuts are the types of cuts made on gemstones. Traditional gemstones are fashioned by placing them on a faceting machine with a flap lap tool, which grinds away and polishes the stone. Fantasy cut gemstones have grooves, optic dishes, and concave facets – all made possible by the development of tools to cut these design elements into gem materials.

	John Dyer’s 27.47 ct multicolor Oregon sunstone is an objet d’ art. Photo by David Dyer, gem courtesy of
	John Dyer & Co.

	Size of the gemstone is an important consideration to lapidaries: the larger the gem, the larger the “canvas.” Some cutters use diamonds and the Big Three (rubies, sapphires, and emeralds), but these materials are often difficult to obtain in large sizes. So many cutters chose gemstones that provide larger canvases, like quartz and aquamarine.

	“I trusted my intuition when I made Wind. I just started creating without any planning,” says Michael Dyber. The finished piece evokes a fierce storm frozen in time. Photo by Sena Dyber

	The world of fine jewelry and the fantasy cut may be far apart, yet a profound understanding of gemology is required by the craftspeople in each field. It is this love of gemstones that ultimately unites them.

	Dalan Hargrave used a variety of techniques on these three pieces of fantasy cut ametrine. Photo by Robert Weldon/GIA, courtesy of Minerales y Metales del Oriente, Bolivia, SA @chapter:26


Publication Year: 1981 Title: Artificially Induced Color in Amethyst-Citrine Quartz Abstract: Adjacent amethyst and citrine colors in the same crystal of quartz have been reported from South America, although there appears to be uncertainty as to the exact locality of origin. Such material has also been produced by synthesis. Several previous studies on the impurities contained in natural and synthetic quartz and the effects of irradiation and heating, as well as new heating and irradiation experiments with the current natural amethyst-citrine quartz and with amethyst, are described. It is concluded that there are presently no known tests to distinguish natural bicolor material that was heated or irradiated (or both) in nature from natural amethyst heated or irradiated (or both) by man or from the equivalent synthetic material. @chapter:10


Publication Year: 2021 Title: An Unusual Treated Agate Presented as “Shi Zi Hong” Agate from Liangshan Abstract: Figure 1. This 5.74 ct treated agate sample (left) submitted to the lab resembled “Shi Zi Hong” agate (right). Photo by Su Xu.

              “Nanhong” agate, an attractive form of agate, mainly ranges from orange-red to purplish red, and is colored by the presence of fine-grained hematite inclusions. Nan and hong mean “south” and “red,” respectively. The material has gained great popularity in China’s domestic gem market in recent years. “Shi Zi Hong” agate, one of the most famous color varieties of “Nanhong” agate (Lin Li, “Analysis of gemological and petrological characteristics of Nanhong agate from Liangshan,” Chengdu University of Technology, China, pp. 17–18), usually has a more vibrant saturated orange-red color and fine texture, so its price is higher. Shi zi and hong mean “persimmon” and “red.” The majority of fine-quality Shi Zi Hong agate on the market has come from Liangshan Yi Autonomous Prefecture in Sichuan Province, China.

In October 2020, an orange-red cabochon sample was presented to the National Gold-Silver Gem & Jewelry Quality Supervision & Inspection Center (Sichuan) by a client who claimed it was a new type of Shi Zi Hong agate. The trader referred to it as “Meng Liao” agate (figure 1, left).

The sample weighed 5.74 ct, and the appearance was similar to Shi Zi Hong agate (example shown in figure 1, right). The spot RI reading was around 1.54, and the sample was inert to UV radiation. Microscopic examination showed cryptocrystalline texture with red pinpoint-like inclusions scattered throughout, most of which were sufficiently fine to appear as hazy clouds under 40× magnification.

Raman spectra of the substrate and red pinpoints were obtained using 532 nm laser excitation. According to the RRUFF online database, peaks at 126, 205, 261, 353, and 464 cm–1 indicated that the main constituent of the substrate was quartz, while the red pinpoints matched that of hematite, with peaks at 224, 244, 291, 410, 610, and 1320 cm–1 (figure 2). Both were consistent with Shi Zi Hong agate. A sharp peak at 501 cm–1, seldom observed in Shi Zi Hong agate, appeared in the spectra of the sample. This significant peak was assigned to stretching vibrations of (SiO4)4– in the moganite structure.

Figure 2. Under magnification and using fiber-optic illumination, some fine pinpoints were distributed as hazy clouds in the rough agate. Raman spectroscopy identified the main constituent of substrate in the sample as quartz (green trace) and red pinpoint as hematite (red trace), both consistent with “Shi Zi Hong” agate (indicated by the purple trace and the black trace). The sample also showed a sharp peak at 501 cm–1 and a broad band at 660 cm–1, neither of which are seen in genuine “Shi Zi Hong” agate. Photomicrograph by Su Xu; field of view 0.22 mm. Spectra offset for clarity.
Based on a negative correlation between the relative content of moganite and the crystallinity of agate (Zhou Dan-yi et al., “Study on the relationship between the relative content of moganite and the crystallinity of quartzite jade by Raman scattering spectroscopy, infrared absorption spectroscopy and X-ray diffraction techniques,” Rock and Mineral Analysis, Vol. 3-4, No. 6, 2016, pp. 652–658), we concluded that the crystallinity of natural Shi Zi Hong agate was much higher than that of the sample. Another obvious anomaly was the broad band at 660 cm–1, which was found in the spectrum of the sample but was seldom observed in Shi Zi Hong agate, and this deserved further investigation.

The client admitted that the “Meng Liao” agate was actually a normal brownish yellow agate heated by a low-temperature process. Meanwhile, he loaned us an untreated rough stone (figure 3) for Raman analysis of its body and very fine yellow pinpoint inclusions.

Figure 3. The untreated brownish yellow rough stone, approximately 17.0 × 22.0 × 1.5 mm, loaned by the client for analysis. Photo by Xiaoping Shi.
The substrate of the untreated rough stone and the “Meng Liao” agate sample submitted to the lab showed almost the same peaks in the region of 1000–100 cm–1, suggesting that they might be homologous with each other. The spectrum of the yellow pinpoint, exhibiting peaks at 299, 389, 415, and 550 cm–1 and lacking a 660 cm–1 band, matched the Raman spectrum for goethite and was related to the formation of color in the rough, as shown in figure 4. According to a previous report (D.L.A.de Faria and F.N. Lopes, “Heated goethite and natural hematite: Can Raman spectroscopy be used to differentiate them?” Vibrational Spectroscopy, Vol. 45, No. 2, 2007, pp. 117–121), the disordered hematite structure was initially formed by dehydration and caused the relative intense band at 660 cm–1 by heating goethite at a low temperature (~140°C to 360°C).

Figure 4. Raman spectra of the brownish yellow rough stone: Peaks at 299, 389, 415, and 550 cm–1 indicated goethite. Peaks at 126, 205, 261, 353, 464, and 501 cm–1 were consistent with the treated agate sample submitted to the lab. Spectra are offset for clarity.
The natural hematite in Shi Zi Hong agate, by contrast, has features including a very weak 660 cm–1 band and a high degree of order, by which genuine Shi Zi Hong agate can be distinguished from the brownish yellow agate that acquired an orange-red color by artificially heating goethite. These results show that the agate submitted by the trader as “Meng Liao” agate, resembling Shi Zi Hong agate, can be readily detected by its unique Raman spectrum displaying an obvious broad band at 660 cm–1 and a sharp peak at 501 cm–1. Consumers in the market for Shi Zi Hong agate should watch out for this treated material. @chapter:3


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

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

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

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

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

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

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

Figure 1. This chart illustrates the steps in the screening and identification of lab-grown diamonds.
In the case of some rare near-colorless clean CVD-grown diamonds that do not show fluorescence or have a birefringence pattern that is coarse but resembling tatami in type IIa and weak patterns in natural Ia diamonds, additional tests using advanced spectroscopy and strong short-wave UV light to observe growth patterns are needed to confirm diamond genesis. @chapter:11


Publication Year: 2022 Title: Many Faces of Wavellite Abstract: Figure 1. This specimen of wavellite in matrix shows the mineral’s characteristic radiating pattern. Photo by GIA.
A well-known collector mineral, wavellite (Al3(PO4)2(OH)3•5H2O), is named after its discoverer, British surgeon Dr. William Wavell. Wavellite mineral specimens seen on the market often occur as botryoidal aggregates. The crystal clusters are usually spherical in appearance. When the spheres are broken open, the cross sections show their signature radiating pattern formed by acicular-shaped crystals (figure 1).
Wavellite is not a gem material renowned for its brilliance or breathtaking colors, but its unique appearance does trigger curiosity and creativity. At the AGTA show, James Carpenter of Unconventional Lapidarist (Hot Springs, Arkansas) showed the authors a variety of wavellite cabochons and slabs and shared how he stabilizes the material for jewelry use.
All wavellite carried by Unconventional Lapidarist is sourced from Arkansas, one of the well-known sources for this gem. When used in jewelry, wavellite must be stabilized (figure 2) to make the piece durable. This is due to both the relatively low hardness of the material (3.5–4) and its occurrence in the host rock. Arkansas wavellite formed in veins cementing together brecciated sandstone/chert host rock. Therefore, the majority of wavellite specimens occur as very thin slabs or small spherical bodies.

Figure 2. Left to right: Wavellite rough before treatment, stabilized rough, a slab of stabilized rough with all the waste host rock trimmed off, and two pieces of polished stabilized wavellite cabochons (89 and 405 ct, respectively). Photo by Tao Hsu; courtesy of Unconventional Lapidarist.
Carpenter noted that 99% of the production needs stabilization for the materials to withstand further processing. He developed his own resin for this stabilization process. This resin is hydrophobic, meaning it is water resistant, and environmentally and biologically friendly. The material is impregnated with this resin in a vacuum under very high pressure and then cured and sliced. Slicing helps reveal where the wavellite is embedded in the host rock. Host rock that bears no wavellite is trimmed off before further polishing. Restabilization is sometimes necessary, especially when cabochons are to be made, to ensure the finished product is durable when set in jewelry. The yield of this process is only about 15%, with 85% waste.
Stabilized wavellite can then be polished to cabochons (figure 3) and mounted in jewelry, with high-quality material revealing an attractive botryoidal structure of rounded segments and/or radiating patterns with beautiful colors. The slab can also be utilized without much polishing (figure 4, left). The latter option works perfectly for stones showing the botryoidal exterior. When one turns this type of cabochon on its side, some of the broken spheres clearly show the radiating pattern, adding appeal to the jewelry piece (figure 4, right). Wavellite can be collected as mineral specimens or used as decor and jewelry material.

Figure 3. This wavellite cabochon is of high quality. Some of the spheres were sliced open to show the radiating pattern, while others were left untouched. Wrapped in gold-plated wires, the cabochon weighs 150 ct, with a blue apatite mounted at the top. Photo by Tao Hsu; courtesy of Unconventional Lapidarist.

Figure 4. Left: This piece of wavellite slab kept the original look of the rock with its botryoidal habit. Right: The view from the side reveals the radiating pattern on the cross sections of sliced-open spheres. Photos by Tao Hsu; courtesy of Unconventional Lapidarist. @chapter:2


Publication Year: 2006 Title: The Cullinan Diamond Centennial: A History and Gemological Analysis Of Cullinans I And II Abstract: The year 2005 marked a century since the discovery of the largest gem diamond ever found: the 3,106 ct Cullinan. Eight decades after it was mined, a team of gemologists conducted the first modern examinations of the two largest diamonds cut from the rough, the 530 ct Cullinan I and the 317 ct Cullinan II, which have been part of the Crown Jewels of England since their presentation to King Edward VII in 1908. This article traces the history of this famous piece of rough and its source, South Africa’s Cullinan (formerly Premier) mine, which has yielded more significant diamonds than any other single locality. It also presents the full details of the examination and grading of these two approximately D-color, potentially flawless historic diamonds. @chapter:29


Publication Year: - Title: Sunstone Care and Cleaning Abstract: With proper care, sunstone can provide a lifetime of jewelry-wearing pleasure. – Mike Havstad

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.

Feldspars, including sunstone, share two traits that affect their durability and make them vulnerable to damage. These are softness—at 6.5 to 7.2 on the Mohs scale—and cleavage in two directions, which gives sunstone a Poor toughness rating.

When sunstone is mounted in a setting that protects it, however, it’s an excellent choice for jewelry. Protective settings include pendants, earrings, and pins rather than rings, which are more likely to receive knocks and bumps.

	Sunstone’s hardness falls between 6.5 and 7.2 on the Mohs hardness scale.
Stability
Exposure to heat is not recommended for sunstone, but its color is stable when exposed to light and won’t fade.

Cleaning
Warm, soapy water is always a safe sunstone cleaning method. Ultrasonic and steam cleaners should be avoided. Feldspars are rapidly attacked by hydrochloric acid, so cleaning products containing bleach should also be avoided.
Rarely, sunstone might be fracture filled. These stones should only be cleaned with warm, soapy water. @chapter:23


Publication Year: 1990 Title: Well-Formed Tsavorite Gem Crystals from Tanzania Abstract: Green grossular garnet crystals of fine form and clarity have been found recently in Tanzania, at the Karo pit of the tanzanite mining belt. Although the crystals tend to be relatively light in color, they are consistent in gemological properties and composition with the grossular variety popularly known as tsavorite. The very distinct and complex morphology of these crystals is remarkable. Eight different crystallographic forms have been identified, including one that has never before been recognized for any member of the garnet group. @chapter:5


Publication Year: 2023 Title: Gemmes Abstract: The new French-language digital publication Gemmes, published by Gemmologie & Francophonie.
Swiss-based Gemmologie & Francophonie has launched a French-language digital publication, Gemmes (see above). Released twice a year, the magazine covers a range of gem and jewelry topics and is open to submissions. Each article has an English-language abstract and figure captions. The debut issue can be downloaded at gemmologie-francophonie.com/index.php/la-revue-gemmes. The second issue, available in September, will examine lab gemology, art history, ethics, and more. @chapter:26