Title: A Perfect Combination of Craftsmanship and Design: An Interview with Leading Chinese Jewelry Designer Shirley Zhang Abstract: Shirley Zhang is a well-known Chinese jewelry designer. Her designs combine western craftsmanship and oriental aesthetic standards. – Photo courtesy Shenzhen Meiher Jewelry Ltd.

                      Shirley Zhang had never planned to be a jewelry designer when she took her first job as an accounting officer in the subsidiary jewelry company of People’s Bank of China. Due to her dedication and passion, she quickly became involved in that company’s management. Influenced by the business she dealt with every day, Shirley fell in love with the colorful world of gemstones and jewelry.

After receiving her FGA gemology degree in the early 1990s, Shirley stepped into the jewelry industry. Since then, she has steadily grown her own career as a jewelry designer. She is now one of the leading jewelry designers in China—one who is also recognized by professionals of the western world.

Shirley has created her special “z” style jewelry concept, which places emphasis on a combination of western craftsmanship and oriental aesthetic standards, and encompasses use of multiple materials and haute couture services. This concept has brought Shirley’s designs industry recognition as being representative of modern, elegant Chinese jewelry.

	From retailer to designer
Between 1978 and 1990, the jewelry trade slowly grew out of the ruins left by China’s Cultural Revolution.  The industry’s revival began after China re-opened the country to trade in 1978. Most merchandise on the market consisted of fine gold products, including some jewelry styles made with very simple craftsmanship. Consumer choices were very limited and they generally lacked knowledge about gemstones or jewelry.

The next five years (about 1989 to 1995) witnessed a huge expansion of the industry. Many local jewelers opened businesses with big investments. Several Hong Kong and Taiwan jewelry companies sensed the potential of the mainland China market and started acting on that awareness. Consumers started paying more attention to jewelry styles and fashion trends, but their tastes were usually influenced by big promotional campaigns like those run by De Beers and others.

At that time, very few Chinese businesses understood the important role that branding played in merchandise promotion. Shirley opened a chain of retail jewelry stores in 1994. In 1996, she wrote her English name, “Shirley,” by hand, and used it as her brand. Within a short period of time, she had opened branded retail stores in 14 different cities in mainland China. Their success brought her more opportunities and access to the western world.

After 1995, the market became more regulated and consumers more mature. Shirley had started her retail stores right at the beginning of this period. Although business was good and profit was guaranteed, her merchandise had nothing—no “stories” of its own—to distinguish it from other brands.

Around 1999, Shirley was, for the first time, shocked by the big gap in jewelry design between the western world and the newly expanding Chinese market. During her first trip to Italy, she visited many jewelry stores and came to the realization that something was missing from her own brand in China. Instead of keeping the stores running, she made the very brave decision to shut them down.

She became a full-time buyer for Chinese jewelry import companies. This turned out to be a smart move and a turning point in her career. As a buyer, she had the opportunity to travel the world and meet experienced jewelry professionals. Her most important goal was to learn from their experiences and use that knowledge for her own career development.

Some of Shirley’s clients in Europe consider her jewelry taste to be very unique. Unlike many of her Chinese peers, she tended to purchase higher-quality goods that were also highly fashionable. This left very positive and pleasant impressions in her clients’ minds. Along with her unique tastes, Shirley is also a fast learner, pays a lot of attention to detail, and grasps every opportunity to learn from others.

Shirley’s design career really began with an education in craftsmanship. In Europe, she purchased jewelry pieces with elegant or complicated craftsmanship. Instead of wearing them, she took them apart and re-assembled them to analyze the manufacturing techniques used to make them. She also attended workshops and learned from master goldsmiths.
The experience Shirley gained from participating in the European market also triggered her consciousness of the oriental aesthetic. At the same time, the design concept of oriental artistic jewelry started to form and grow in her mind.

Taking the advice of an Italian friend, after seven years as a buyer she opened her own studio in 2004 and started to manufacture jewelry for some of her European clients. Although she designed some pieces here and there, most of the designs were still provided by her western colleagues. Gradually, her role started to shift. Eventually, she became both designer and manufacturer. Now she focuses solely on designing jewelry and developing new manufacturing techniques. She leaves most of the actual manufacturing work to the employees in her studio.

	In the molding department of her jewelry manufacturing studio in Shenzhen, Shirley displays a silver mold of one of her designs. – Photo by Eric Welch, © GIA

	Shirley now spends more time on high-end jewelry design and leaves most of the manufacturing work to her employees. – Photo by Eric Welch, © GIA

	A perfect combination of western craftsmanship and oriental aesthetic standards
Shirley’s design inspirations come mostly from her daily life. For example, her love of birds and flowers inspired her to design the series called “The Spirit of Peacock” and “The Love of Flowers.” In her work, she pays special attention to color and the arrangement of various objects in a design.

As a newly assigned board member of the ICA (International Colored Gemstone Association), Shirley made a presentation about color’s influence on her jewelry designs at the 2013 ICA Congress in Changsha, China.

Color played a very important role in the development of China’s jewelry design industry. From the all-the-same green and gray uniforms people wore during the Cultural Revolution to the pale red and blue sapphire rings people preferred in the 1980s and 1990s, Chinese consumers have made a lot of progress, gradually adjusting to the fast-developing economy and changes in lifestyle. Life in this new century has been colorful to a level unprecedented in China’s history.

Sensing this change, Shirley uses colors boldly in her designs. In some designs, she emphasizes the fine colors of the gemstones themselves. In other pieces, she tries to demonstrate harmony by combining different colors. She also likes to match colors with different shapes or cultural themes. She loves to use colors but is not limited by them.

Besides color awareness, Shirley also has the unique ability to combine different materials. She often lays out a lot of different materials in her studio and tries different combinations of a variety of materials and jewelry parts and varied types of craftsmanship. For example, she tries to combine faceted stones and cabochons, metal and wood, china and crystal gems, enamel and gems, and more. Her creative combinations awaken the spirits of all these varied materials.

	Shirley has designed many jewelry pieces with animal themes. She used a very unique inlay method to show the peacock’s colors in this jewelry set, which is called “The Spirit of Peacock.” – Photo courtesy Shenzhen Meiher Jewelry Ltd.

	Shirley created this design to demonstrate harmony among different colors and shapes. She used carved jadeite to symbolize Chinese culture. – Photo courtesy Shenzhen Meiher Jewelry Ltd.
Unlike many other designers, Shirley was not an art major. She started her design career by learning craftsmanship from experts in the field. Aside from design concepts and ideas, whether or not a design can be turned into an actual jewelry piece is another serious consideration. Besides designing jewelry, Shirley has spent a huge amount of time researching and developing new craft skills and techniques. The combination of traditional lost-wax casting and die-striking in the creation of a single jewelry piece is one of her famed inventions.

Over the past 10 years, she and her colleagues have gained numerous patents for jewelry manufacturing and stone-cutting techniques. Her research and exploration distinguished her from her competitors and gave her a leading position in China’s jewelry design industry. Shirley is very familiar with jewelry manufacturing techniques and the market’s current fashion trends. When faced with the question of how to make her “Shirley” brand stand out, she chose to combine western and oriental cultural elements in her own unique way.

	This is a see-through enamel finished product. Shirley Zhang’s factory is the only manufacturer of see-through enamel in China. – Photo courtesy Shenzhen Meiher Jewelry Ltd.
Consumers’ needs inspire and guide Shirley’s designs. She states that before she sketches a design for a consumer, she needs to have knowledge of new fashion trends as well as of the consumer’s personality and color preferences. If she is designing for a brand, she must know what the brand strategy is. She needs answers to all these questions before she starts working. In her eyes, whether a design is pretty or not is not as important as whether or not it matches the customer’s style. She wants her design to best represent the heart and inner being of her client.

	Artistic jewelry: new ideas for the rapidly developing Chinese jewelry market
Shirley’s more than 20 years’ experience as a jewelry professional parallel the biggest changes in the history of the Chinese jewelry industry. Shirley and her business experienced a lot of those changes along with the industry.

Market changes are usually directly influenced by consumers. Twenty years ago, because Chinese consumers focused only on the material the jewelry was made of, most jewelry stores carried only fine gold jewelry. Besides the rich history of gold jewelry in China, value retention was the main reason for consumers to buy. Later, people slowly gained knowledge about gemstones like diamond, ruby, and sapphire. The promotions done by some international brands influenced Chinese consumers to start accepting jewelry pieces set with gems, even while they remained focused mainly on the value of the precious metal and stones.

At the time, all stone-set jewelry had a similar look, so the emphasis was on specific jewelry features. For example, a buyer looking for a piece of jewelry would insist that it be set with a 10-point diamond with a clarity grade of VVS or above and color grade of G or better.

About five years ago, Shirley noticed some sharp shifts in the market. Before that, her clients had been mostly from overseas. Today, she serves mainly domestic clients, both individuals and known brands. Her customers fall into four main categories: investors, collectors, accessory-driven clients, and those who value China’s cultural inheritance. Consumers no longer focus only on materials. Today, they pay more attention to jewelry designs. She admits that there are still big differences among various demographic groups. Older consumers still want better-quality materials that keep their value, while young people prefer fashionable and unique designs without much regard for the stones used.

	This is an example of the designs Shirley creates for her high-end customers. It’s a great combination of manufacturing skills, color, and shape. – Photo courtesy Shenzhen Meiher Jewelry Ltd.
Shirley shares the same views as other designers in terms of jewelry buyers’ motivations. She sees no big difference between international and domestic consumers. She does see that more and more young Chinese office workers are buying jewelry for themselves as rewards or gifts. This is similar to what happened in the US, when more women became independent and went off to work.

To satisfy the mature western jewelry market as well as the newly developed Chinese market, Shirley and her team have designed many jewelry series that have been well accepted and appreciated by consumers. Some examples are “The Love of Flowers,” “Birds Chirping,” “Spirit of Jadeite,” and “Dancing on the Flowers” as well as some new-technique enamels. These products all provide a combination of western craftsmanship and oriental aesthetic standards that have become consumer favorites.

Shirley and her colleagues are very optimistic about the future of the Chinese jewelry market. Chinese consumers are fast learners as well as great inheritors of their ancestral culture. They are quickly educating themselves and becoming some of the most powerful buyers in the world. Shirley says that all designers should realize this and be ready to supply this market without being left behind.

	Skilled craftsmanship and western and oriental aesthetic standards combined with haute couture services
Successful jewelry designers usually have their own art studios. Shirley’s business model is quite different from most of the others. Its uniqueness is apparent in the company name: Meiher Jewelry Styling Research Center.

The GIA team visited Shirley’s company in June of 2013. The visit began with a factory tour. It was not a big factory. Shirley repeatedly emphasized that she tries to include every step, from design to finished product, in this small factory. She maintains full contact with all these steps so she can research and develop new techniques. The factory serves as both a production line and a lab.

She proudly informed us that Meiher is the only jewelry company in China that can make transparent enamel. Enamel is usually painted on some sort of base material. This new technique eliminates the base and lets the enamel stand alone, allowing people to see through it. Several technicians are working hard to develop this technique and they already have created some finished product.

	In Shirley’s factory, you can observe every jewelry-making step. The facility includes a die-striking department. – Photo by Eric Welch, © GIA
For the past ten years, Shirley has designed for many famous jewelry brands in China—both commercial quality and high-end. Today, she focuses mainly on the haute couture market. Her design studio in Beijing serves only celebrities and other high-end customers.

	This exhibition, held for high-end clients, displays customized jewelry designs by Shirley Zhang. – Photo courtesy Shenzhen Meiher Jewelry Ltd.

	A milestone in Shirley’s design career
When many people think about Shirley, the first design that comes to mind is her award-winning piece, “Dancing on the Flowers.” Inspired by the way bees interact and work together diligently, Shirley brought her passion for gemstones and manufacturing skills into designing this jewelry suite. The suite was given a special award as the gift for the “20 years’ accomplishments of the Chinese jewelry industry” at the 2012 NGTC (National Gems & Jewelry Technology Administrative Center) jewelry design and manufacturing skills competition.

	This is Shirley’s award-winning jewelry suite called “Dancing on the Flowers.” The suite was designed and manufactured by Shirley Zhang. – Photo courtesy Shenzhen Meiher Jewelry Ltd.
To emphasize the “accomplishments” aspect, along with the theme of the jewelry design competition, which was “impression,” Shirley chose to use different gemstone varieties and apply different mounting and cutting styles. The suite includes a cape, a cuff bracelet, and a pair of earrings. Colorful bees are busily working on the flowers and bringing honey back to their beehives, which consist of numerous cells. The design symbolizes the people in China’s jewelry industry who, like the bees, diligently contribute to the industry’s accomplishments and growth over the past 20 years.

Of the three items, the cape is the most breathtaking. It is more than 1 meter (3 feet) long, and made by applying traditional lost-wax casting and die-striking. It features newly developed “dumbbell” buckle links and a patented “honeycomb” setting. The “dumbbell” buckle link effectively connects all the beehive cells and allows them to move freely together as well as individually. When it is worn, it drapes on the wearer’s shoulder and conforms to the body. The wearer feels the fabric-like softness created by the special link system.

Another advantage of this link system is that it is easily assembled or taken apart, which gives its wearer maximum wearing flexibility. The owner of this cape can actually create other jewelry pieces by disassembling it or assembling it in a different way.

Close attention to the flowers on the cape and the cuff bracelet reveals the special mounting, called a “honeycomb” setting. By applying this technique, both sides look the same because light is able to travel through the gemstones. Previously, it was difficult to mount stones in a floral design because larger stones don’t easily fit in and the backs of the flowers have a very unpleasant look because the light is blocked. The earrings are also delicate in their design. The honeycomb pattern allows people a 360-degree view of the earring. The inner and outer spheres can move individually.

This jewelry suite is set with 1,002 colored stones and 4,986 diamonds. It contains both extremely expensive, high-quality jadeite cabochons and very affordable chalcedony cabochons. Shirley also tried to use gemstones of different cuts and sizes. Shirley has many famous designs, but she says this is definitely her favorite, since it is a perfect combination of her design and delicate craftsmanship techniques.

Through the years, Shirley has devoted herself to the study of different gem materials and jewelry manufacturing techniques. She created and patented new jewelry-making methods and revived old ones. Her designs express her love of nature. Shirley and her colleagues have kept bringing surprises to the industry.

	Suggestions and expectations for future designers
Before our formal interview, Shirley talked about her experience as a mentor and advisor of young jewelry designers and jewelry design students. As a NGTC professional instructor, she travels to different cities to give lectures on jewelry design and manufacturing. At the same time, she gets invitations from universities with jewelry design programs to lecture the students. Shirley came to notice that when she looked at the designs the students presented to her, she realized that many of them couldn’t be manufactured.

The students were good at presenting innovative ideas, but did not know much about the craftsmanship side of the business. Many of their educational programs only teach the students how to design a piece of jewelry instead of how to design and then make it. Based on her personal experience, Shirley believes that it makes more sense to learn craftsmanship before design concepts.

In this information era, young people are surrounded and sometimes overwhelmed by all the information they can easily access. Shirley hopes that students can “stay down to earth.” She says that young designers can’t be successful without being good at both craftsmanship and design ideas. Source: GIA @topic:9


Title: Let Jewelry Tell the Story: An Interview with Chinese-Style Designer Yue-Yo Wang Abstract: Jewelry designer Yue-Yo Wang, from Taiwan, is the founder of Wang Yue-Yo Creative Jewelry Design. Photo courtesy of Wang Yue-Yo Creative Jewelry Design.

                      China has a long history of jewelry design. For thousands of years, the Chinese people have used jewelry for self-adornment. Today, more and more western designers are implementing oriental elements into their jewelry.

Yue-Yo Wang, a jewelry designer from Taiwan, has devoted herself to traditional Chinese jewelry design. She has combined the Chinese knotting art with modern jewelry design and manufacturing techniques to create her own pieces. Every finished piece has its own story.

	Yue-Yo’s designs feature large, high-quality materials, applied in the “Chinese Style.”
	Photo courtesy of Wang Yue-Yo Creative Jewelry Design.

	Chinese Knotting Art
In China, knotting art can be traced back to around 1600 BC. Before that time, knotting had a more practical purpose, which was to record important events or numbers on a daily basis. After that, with the development of written record-keeping, knotting gradually lost its practical purpose and became more decorative.

Chinese knotting art experienced a peak from around 600 AD until the early 1900s. Along with most of the other arts, its development paused during a 100-year span of social upheaval in China. Currently, knotting is being picked up once more by younger generations, who have developed a high appreciation for this ancient art. Knotting threads are made of a variety of materials. Knotting art can be used for room decorations or jewelry pieces. China has even established qualifying exams at different levels for experienced knot makers.

At one time, Yue-Yo enjoyed a very relaxed and easy life as a housewife and collector of Chinese artistic teapots. When an unforeseen event affected her husband’s business, her easy life ended and she had to start making an income. She began a small business to sell her teapot collection along with some of her knotted teapot covers.

She gradually fell in love with knotting and decided that she could use it to add to her profits. She spent time developing her knotting skills and, after a short period of time, became a well-known knot maker. People advised her to establish a knotting art education program and many students came to learn from her, some of them from overseas.

Although knotting products and classes increased her profits, they still required a lot of labor and sold for relatively low prices. She often had to work extra hours or overnight to complete orders. This situation inspired her to look for a more efficient way to add value to her products. She tried using knotting techniques on clothes, decorations, and other articles. Then she came up with the great idea of combining knotting art with modern jewelry manufacturing methods.

She was not yet a jewelry designer, so she passed most of the knotting work to her students and set out to learn jewelry design. Accomplishing this turned out to be a great advantage for her jewelry company, which was very successful even when the global economy was suffering.

	Knotted thread was used to create the wrapping band on this jewelry piece.  Photo
	courtesy of Wang Yue-Yo Creative Jewelry Design

	The headquarters of Wang Yue-Yo Creative Jewelry Design in Taipei. Photo courtesy of Wang Yue-Yo Creative Jewelry Design.

	Personal and Company Growth
Yue-Yo has been part of the jewelry design industry for about 20 years. In that time, her company has experienced several important development stages.

From 1993 to 1999, Yue-Yo Wang Creative Jewelry Design concentrated on promoting the design concept of “Chinese style” jewelry. They participated in many large international jewelry shows to attract international consumers and build the company image. From 2000-2005, Yue-Yo and her colleagues increased their participation in a variety of social works while further developing their jewelry design and manufacturing techniques.

Around 2005, she sensed the rapid development and huge potential of the mainland China jewelry market. She and her team headed west to explore this major market. So far, since then they have opened more than 10 stores all over mainland China, including their guild store, which opened in 2007 in Beijing. In 2008, Yue-Yo was asked by Beijing Shanyuan Jewelry Company to jointly design the Beijing Olympics souvenir crystal dragon stamp. This event gave her and her designs more public exposure and also made her more confident about the future of “Chinese style” jewelry.

In 2012, Yue-Yo turned another dream into reality by forming the Taiwan Creative Jewelry Design Association. She hopes that this organization will attract more jewelry designers who focus on artistic jewelry design and would like to spread the Chinese culture to the rest of the world.

	Yue-Yo designs not only jewelry, but also “Chinese style” clothing. Her jewelry and clothes go perfectly together.  Photo courtesy of Wang Yue-Yo Creative Jewelry Design.

	This is the exterior of the company’s guild store in Beijing. Photo courtesy of Wang Yue-Yo Creative Jewelry Design.

View Gallery

	This slideshow exhibits representative Chinese style jewelries as designed by Yue-Yo Wang.

	Jewelry Design Concepts and Inspirations
A careful look at Yue-Yo’s design always reveals some traditional Chinese symbols and some elements from Chinese knotting art, like long tassels and thread patterns The main focus of her designs is to combine different symbols to create a scene or a story.

	Birds, flowers, tassels, and Chinese character patterns are common elements in
	Yue-Yo’s designs. Photo courtesy of Wang Yue-Yo Creative Jewelry Design.
Yue-Yo’s designs are usually inspired by the stones in her hands. She believes that every gem has its own spirit, and she is inspired to find it and express it to people. Since her main business is now high-end customized design for consumers, she pays a lot of attention to the quality of the gem materials and the manufacturing details of her jewelry. She employs her own jewelers, so it is very easy for her to work with them and pass along her ideas to them. Some of her jewelers have more than 30 years of experience in the industry.

Materials that she uses most commonly in her designs include opal, coral, jadeite, tourmaline, and chalcedony. She likes coral the most, because coral is one of the three symbolic gems of Taiwan. Before, rough coral was often exported to Japan and other countries to be carved, so she felt that the Taiwanese did not take full advantage of their own gems.

She began to use coral in her knotting projects, attracting respect and appreciation from coral dealers. Then she found that the real high-quality corals are not fit for knotting because holes usually needed to be made. She now uses other high-quality material in her high-end design products.

	High-quality coral from Taiwan is Yue-Yo’s favorite gem material to use in her haute couture products. Photo courtesy of Wang Yue-Yo Creative Jewelry Design.

	Passing Skills to the Next Generation
Yue-Yo Wang is not just a designer; she is also a great instructor. She enjoys talking to young people. At every jewelry show she participates in, she likes to talk to young students who want to be jewelry designers.

She still teaches knotting and jewelry design to young people (Fig.9). Many of her students started good careers after being trained and helped by her. In the future, she plans to work more on jewelry design education and the spread of Chinese culture, working through her own company and the organization she formed.

	Yue-Yo teaches jewelry design students in order to pass her design skills to the next generation. Photo courtesy of Wang Yue-Yo Creative Jewelry Design. Source: GIA @topic:6


Title: Summer Fashion Ideas: Colorful, Playful Jewelry Abstract: As summer heats up, stylish women will keep their cool with sophisticated, playful jewelry with an accent on color.

There is an emphasis on delicate pastels in summer jewelry – the kind you would find on a baby’s blanket: powder blue, soft turquoise, blush pink, mint green, and pale yellow. Translated into gemstones by gem and design experts at GIA, this means aquamarine, blue topaz, blue and pink sapphire, pink and green tourmaline, peridot, citrine, yellow sapphire and chalcedony – and don’t forget about the classic pearl. For the ultimate in flattery to all complexion types, look for soft, luminescent gems in misty colors such as pearl, moonstone, chalcedony, rose and smoky quartz.

With all casual, warm-weather fashions, the must-have jewelry items are playful and full of movement. Consider a sun, moon, or star pendant in silver, gold, or dotted with gemstones, worn swinging from a long rope or leather cord. The season’s dangling earrings can reach nearly to the shoulders, and are often capped off with sparkling beads or briolettes (teardrop-shaped gems that are faceted or smooth).

The shapes of the jewelry, like the cut of the clothes, are classic yet modern for the summer. Favored motifs include hearts, circles and ovals, and necklaces feature repeating patterns of geometric links. In pendants and earrings, look for designs within designs, such as a series of concentric circles or hearts within hearts. Rings have soft shapes too, with smooth, domed cabochons in oval and round shapes.

Another strong theme for summer relies on color to make its point. This look, more sophisticated than the baby pastels, is exotic, with Indian/African/Asian themes alive with vibrant patterns and colors. Necklaces and pendants are worn in multiples; earrings are bold and oversized; and a single cuff or multiple bangles cover the arms.

Animal patterns, such as leopard, tiger, and zebra motifs, remain strong in clothing and accessories. Decorative designs such as paisleys, calligraphy, petals, and leaves add punctuation to summer dressing. Choose a large floral pin to wear in your hair or on a shoulder by day; switch to drop earrings dotted with sparkling gemstones by night.

Whether your summer jewelry selections include sparkling diamonds, alluring colored stones, or lustrous pearls, always deal with a reputable jeweler, like a GIA Graduate Gemologist, Graduate Jeweler or Accredited Jewelry Professional. Their training is backed by the world’s foremost authority in gemology – GIA. A GIA Diamond Grading Report should accompany any significant diamond purchase. Source: GIA @topic:6


Title: Winter 2001 G&G Book Reviews Abstract: “Gemstones: Symbols of Beauty and Power”
By Edward Gübelin and Franz-Xaver Erni, with photographic contributions by Erica and Harold Van Pelt, 240 pp., illus., publ. by Geoscience Press, Tucson, AZ, 2000. US$49.95

“The Jeweled Menagerie: The World of Animals in Gems”
By Suzanne Tennenbaum and Janet Zapata, 216 pp., illus., publ. by Thames & Hudson, New York, 2001. US $45.00

“Diamond: A Journey to the Heart of an Obsession”
By Matthew Hart, 276 pp., illus., publ. by Walker & Co., New York, 2001. US$26.00

“Barren Lands: An Epic Search for Diamonds in the North American Arctic.”
By Kevin Krajick, 442 pp., illus., publ. by Times Books (Henry Holt and Co.), New York, 2001. US$26.00

“Pearls: A Natural History”
By Neil H. Landman, Paula M. Mikkelsen, Rudiger Bieler, and Bennet Bronson, 232 pp., illus., publ. by Harry N. Abrams, New York, in association with The American Museum of Natural History and The Field Museum, 2001. US$49.50

“Diamonds: Famous & Fatal”
By Leo P. Kendall, 236 pp., illus., publ. by Barricade Books, Fort Lee, NJ, 2001. US$30.00

“Proceedings of the International Workshop on Material Characterization by Solid State Spectroscopy: Gems and Minerals of Vietnam”
Edited by Wolfgang Hofmeister, Nguyen Quy Dao, and Vu Xuan Quang, 334 pp., illus., publ. by Vien Khoa hoc Vat lieu, Hanoi, US$20.00 [e-mail: quangvx@hn.vnn.vn]

“Shinju no Kagaku [Science of the Pearl]”
By Koji Wada, 339 pp., illus., publ. by Shinju Shinbunsaya (Pearl News Press), Tokyo, 1999 [in Japanese], ¥8,500

“Minding the Store”
By Stanley Marcus, 383 pp., illus., publ. by University of North Texas Press, Denton, TX, paperback edition 2001, US$19.95

To view the full section, download the PDF above. Source: GIA @topic:7


Title: Diamond Lattice Defects: GIA Researchers Explore Internal Tagging and Gray-Blue-Violet Diamond Color Abstract: GIA researchers Troy Ardon, left and Chloe Peaker, presented their diamond quantum findings at the recent Princeton-GIA Symposium. Ardon focused on an internal diamond tagging application and Peaker looked at why some diamonds have gray-to-blue-violet color.

GIA scientists presented their latest research on diamond tagging and the cause of gray-blue-violet color in diamonds at the Princeton-GIA Diamond Symposium, sponsored by GIA, on Jan. 24 at Princeton University.
The annual symposium is held to foster collaboration among quantum experimentalists, material scientists and industrial partners. Participants included quantum and materials research groups from the Argonne National Laboratory, Institut Néel Grenoble, City College of New York, Cornell University, CUNY College of Staten Island, IBM Quantum, Princeton and the University of Pennsylvania.
“This symposium is a wonderful way to bring together academic and industry scientists in the area that they are working on in a number of topics related to diamond, materials, spectroscopy and quantum technologies,” said Nathalie de Leon, associate professor of electrical engineering at Princeton and the organizer of the conference. “The discussions and the collaborations that resulted are incredibly valuable, and my students and I have really enjoyed the breadth of topics.”
Internal Diamond Tagging
Troy Ardon, who has a master’s in diamond science and technology from the University of Warwick in the UK and is a research associate at GIA in Carlsbad, presented "Laser Writing the H3 Defect into Natural Ia Diamond," which involves researching how to use laser writing to create an internal tagging system for diamonds.
In order to understand the possibilities, according to Ardon, you need to understand the structure of a diamond. A diamond is made up of carbon bonded together in a repeating structure known as a lattice. Pure diamond is pure carbon, nothing else, he said. It is very common, however, for non-carbon atoms (the most common is nitrogen) to be “substituted” into the diamond lattice. When a single nitrogen atom takes the place of a carbon atom, it is called substitutional nitrogen. A vacancy is just a missing carbon atom - an empty space in the lattice.

These lattice models show the differences between pure diamond, left, and diamonds with defects, center and right. Illustration by Troy Ardon/GIA
“You can combine these defects in a number of different ways, such as the H3 defect – a nitrogen-vacancy-nitrogen structure in the lattice,” Ardon said. “We used high powered focused laser pulses to knock carbon atoms out of the lattice, creating vacancies. The nitrogen was present in the form of A centers. We then annealed (slowly heated) the diamonds to ‘migrate’ the vacancies into the A-center to create the H3. We wanted to see if we could create H3 defects that can be measured above the background – one that ‘stands above the crowd’ so to speak.”
The results?
“We successfully wrote the H3 defect in a natural diamond with a low H3 background without producing visible damage,” he said. “We were not successful in writing a measurable H3 in a diamond with a high background, even with high energy pulses, which means we will have to expand our search for other writeable defects.”
Ardon said this kind of fundamental research from diamond quantum photonics ‒ a catch-all term for diamond optics and the usage of diamond defects as photon sources ‒ can be turned into a potential application for the gem industry: the creation of a robust internal tagging system. The goal is to create a unique serialized mark (similar to a QR code) to help prevent fraud and improve traceability.
“I greatly enjoy using new and fundamental research and applying it to an industry with which most people are familiar,” he said. “It almost provides a conduit to get information about high level research to a wide audience. It’s fun to connect new scientific ideas/methods with real world applications that anyone can understand.”
How do gray-to-blue-to violet diamonds get their color?
Chloe Peaker, Ph.D. and a postdoctoral research associate at GIA in New York, presented "Transition Metal Centers: A Potential Cause of Color in Gray-to-Blue-to-Violet Hydrogen-rich Diamonds," a snapshot of a theoretical and experimental study investigating what defect causes the color of rare gray-blue-violet diamonds.
“The cause of this diamond color has eluded the community thus far,” Peaker said. “The diamonds are rare and very valuable because the color is unique to naturals and has not been seen in laboratory- grown or treated stones.”
The color of the stone can be investigated by looking at the UV-visible absorption spectrum, she said, but from a theoretical perspective, identifying peaks and the responsible defect is inherently difficult.
Peaker said the study initially focused on the identification of the defect that causes the 3236 cm-1 absorption, a well-defined peak seen in Fourier-transform infrared spectroscopy (FTIR), an absorption spectroscopy technique that looks at absorption of light in the infrared range, as opposed to UV-visible spectroscopy that looks at absorption of light in the UV-visible range. The 3236 cm-1 peak is the second most prominent peak after the 3107 cm-1 peak, which was finally identified by combining theory with experimental stress results - after nearly 50 years of research.

In this example of a metal-nitrogen defect in diamond, the lattice is composed of one nickel atom (in red) centered in a vacancy where a carbon atom has been removed. The nickel is surrounded by four nitrogen atoms (blue) and two carbon atoms (gray). This defect is labelled as NiN4V (V refers to the vacancy) and is also referred to as NE8, a label used to identify the spectroscopic signature seen in EPR (electron paramagnetic resonance). Illustration by Chloe Peaker/GIA
“I presented promising theoretical results of metal-nitrogen-hydrogen vibrations that are found in this region of the FTIR spectrum, although an identification based on one piece of evidence is unwise,” Peaker said. “I also speculated on the formation pathway by comparing the spatial distribution of the 3236 with the 3107 peak in mixed-habit diamonds.”
Although more work needs to be done to discover what creates the gray-to-blue-violet color in these diamonds, Peaker is eager to continue her research.
“I would love to be the one that discovers what causes the color,” she said. “Knowing what causes it would be the first step to see how the defect responsible could be reproduced or modified. I would like to find out something that could have wider implications in the diamond industry. It is exciting to research the unknown!”
The opportunity for these researchers to present at Princeton-GIA Diamond Symposium gave them access to more information about quantum theory – the study of the nature and behavior of matter and energy at the atomic and subatomic level – and its possible applications in the study of gemstones.
“The conference was well attended and all the speakers seemed to have put a lot of work into their talks,” Ardon said. “There was quite a lot of discussion about new developments in quantum computing and using diamond defects as qubits, which was fascinating to learn about.”
Peaker was impressed by what she learned about quantum computing.
“Quantum computing has grown in (quantum) leaps and bounds,” she said. “It seems like a promising future in materials science as a whole.” Source: GIA @topic:4


Title: Where Do Blue Diamonds Come From? Blue Diamonds Have a Surprising “Superdeep” Origin and a Link to Ancient Oceans Abstract: Figure 1: Blue boron-bearing diamond, with dark inclusions of a mineral called ferropericlase that were examined as part of this study. This gem weighs 0.03 carats. Photo by Evan M. Smith.

This is an extended abstract of the article ‘Blue boron-bearing diamonds from Earth’s lower mantle,’ published in the journal Nature. GIA Research Scientist Evan Smith is the lead author of the article, with co-authors Steven B. Shirey, Carnegie Institution for Science; Stephen H. Richardson, University of Cape Town; Fabrizio Nestola, University of Padova; Emma S. Bullock, Carnegie Institution for Science; Jianhua Wang, Carnegie Institution for Science; and Wuyi Wang, Gemological Institute of America.

Type IIb diamonds are a rare variety of diamond distinguished by having boron within the crystal structure, which can impart an attractive blue color. The famous Hope diamond is a perfect example of this blue diamond variety. Type IIb diamonds have long remained a geological enigma, but new research published in the August 2, 2018 issue of Nature reveals they are “superdeep” diamonds, meaning they crystallized much deeper in the earth than most other gem diamonds. Remarkably, the boron atoms contained in these blue gems may have originally been derived from ancient oceans.

Figure 2: Rough blue diamonds weighing between 0.7 and 3 carats each. Examining rough samples, such as these, can be a good opportunity to see inclusions, because inclusions are often skillfully cut and polished away to optimize the appearance of the faceted gem. Photo by Evan M. Smith.
Boron is an element that is strongly concentrated at Earth’s surface. But in the mantle, where diamonds grow, the concentration of boron is extremely low. The boron content of type IIb diamonds is therefore unexpected and challenging to explain. Blue diamonds have intrigued scientists for decades, but the high value and rarity of these gems and their near lack of mineral inclusions have been major hurdles to research.

Prior to this study, no mineral inclusion had ever been identified in a type IIb diamond. However, systematic screening of diamonds submitted to GIA over two years made it possible to find and examine 46 type IIb diamonds with inclusions. By studying the inclusions – small pieces of material trapped in the diamond during crystallization – the research team was able to deduce the host rock and depth where the diamonds grew. The minerals identified in these inclusions are only found together at extremely high pressures, very deep in the earth, leading to the conclusion that type IIb diamonds formed at least as deep as the transition zone (410–660 km), reaching into the lower mantle (>660 km). For comparison, this is approximately four times deeper than most other kinds of diamonds, which form near the base of old and thick continents at depths of about 150–200 km.

The inclusions also show that, at this great depth, the diamonds grew in the presence of ocean crust which was carried down to the lower mantle by the conveyor-belt-like process of subduction. The connection with subducted oceanic lithosphere suggests that boron, responsible for the blue color in type IIb diamonds, may have been carried down from the earth’s surface.

Figure 3: Inclusion of calcium silicate in a 0.21 carat blue diamond seen with the field view of 1.42 mm wide. This inclusion is evidence that the diamond grew at extreme depths in the mantle. Photo by Evan M. Smith.
When seawater infiltrates the ocean floor, it causes chemical reactions that deposit boron into the oceanic lithosphere. This new study proposes a model whereby some of this boron is subducted with hydrous (water-bearing) minerals down to the lower mantle. At this great depth, the increased temperature and pressure break down the hydrous minerals, which then release a boron-enriched fluid that triggers diamond growth. Many of the inclusions in the blue diamonds that Smith and his colleagues examined have coexisting methane and hydrogen as a thin layer surrounding the solid minerals, providing evidence of diamond growth from such a boron-enriched hydrous fluid.

This new study reveals not only that type IIb diamonds are among the deepest diamonds ever found, but also that boron and maybe even water can be carried from the ocean deep into the mantle by the process of subduction. This is a key observation for our understanding of mantle geochemistry and plate tectonic processes.

August 2018 Nature cover “Deep Blue,” explores Evan M. Smith’s research on type IIb blue diamonds that formed when boron hitchhikes to Earth’s lower mantle on oceanic tectonic plates. Image courtesy of Nature.
Until recently, it was widely held that superdeep diamonds are always small and never of gem quality. This notion is upended by the present discovery that blue boron-bearing diamonds are superdeep, in addition to the 2016 finding that relatively large and pure (CLIPPIR) diamonds are also superdeep. Thus, many of the world’s most expensive and dazzling gem diamonds are superdeep diamonds, making them invaluable physical samples from the convecting mantle hundreds of kilometers beneath our feet.

Dr. Evan Smith will present this research at GIA’s International Gemological Symposium, Oct. 7-9 in Carlsbad, CA. For more information on the program and to register, visit symposium.GIA.edu. Source: GIA @topic:4


Title: Summer 2017 G&G: Russian Diamonds and PL Mapping of Synthetic Diamonds, Plus Sapphire Inclusions Chart Abstract: The Fall 2017 issue of Gems & Gemology covers topics across the gemological spectrum, from HPHT synthetic diamond identification criteria to natural saltwater pearls harvested during the Columbian era and the current state of Colombia’s emerald industry. Other highlights include a study of photoluminescence spectra in emerald as a method of determining geographic origin, a review of synthetic star corundum from mid-twentieth century Germany, and an examination of the material known in the industry as “dalmatian jasper.”
OBSERVATIONS ON HPHT-GROWN SYNTHETIC DIAMONDS: A REVIEW

While some HPHT synthetic inclusions appear transparent, most appear to be pieces of dark solidified metal flux. A variety of shapes are possible, including thin rods and irregular shapes, and some are associated with feathers. These metallic inclusions can create a magnetic attraction. Photo by Sally Eaton-Magaña.
While synthetic diamonds grown by the high-pressure, high-temperature (HPHT) method have been commercially available since the mid-1990s, the technology has made great strides in the last decade. In the issue’s lead article, GIA’s Sally Eaton-Magaña, James E. Shigley, and Christopher M. Breeding provide insight into the HPHT-grown material available on the market, including statistical data about the cut, color, and clarities available as well as identification criteria for gemologists.
SALTWATER PEARLS FROM THE PRE- TO EARLY COLUMBIAN ERA: A GEMOLOGICAL AND RADIOCARBON DATING STUDY

These natural pearls, reportedly from thepre- to early Columbian era, represent some of the 85samples examined in the study. They were discoveredalready drilled but were only recently strung as anecklace. The center blister pearl (31.41 × 16.86 ×10.25 mm) consists of multiple small pearls thatformed as an aggregate. Photo by Sood Oil (Judy)Chia.
Pearls were treasured by the indigenous people of the Americas and by the Spanish colonists. Oyster beds in the Caribbean were heavily exploited during the first half of the sixteenth century before oysters became scarce. A supplier came into possession of 85 pearls, reportedly from Central or South America and dating from the pre- or early Columbian era. A team from GIA and the Gübelin Gem Lab, led by Chunhui Zhou, analyzes the pearls through a variety of methods to validate these claims.
PHOTOLUMINESCENCE SPECTRA OF EMERALDS FROM COLOMBIA, AFGHANISTAN, AND ZAMBIA

Emerald crystals from Zambia (left), Colombia (top right), and Afghanistan (bottom right). Each emerald’s hexagonal prismatic crystal habit has been enhanced by polishing flat the two hexagonal end faces (perpendicular to the crystal’s c-axis) and two or more prism sides (parallel to the c-axis). Photo by D.B. Thompson.
Photoluminescence (PL) in emerald arises from trace chromium impurities. An emerald’s PL spectrum displays two features that can vary depending on the stone’s origin. Lead author David Brian Thompson and his team examine the PL spectra of 48 emeralds from Colombia, Afghanistan, and Zambia to provide evidence for or against possible geographic origins.
SYNTHETIC STAR SAPPHIRES AND RUBIES PRODUCED BY WIEDE’S CARBIDWERK, FREYUNG, GERMANY

Three synthetic blue star sapphire cabochons and one synthetic star ruby cabochon in direct sunlight. The ruby weighs 8.92 ct and measures 13.2 × 11.0 mm; the sapphire at the bottom left weighs 3.67 ct and measures 9.1 mm in diameter. Photos by K. Schmetzer.
During the 1950s, Wiede’s Carbidwerk patented a method of growing star synthetic corundum for the commercial market. The company sold these goods through the late 1970s, though the samples from the 1960s and beyond differ slightly from their earlier counterparts. Karl Schmetzer and his coauthors explore the variant of the Verneuil process that Wiede’s used to grow these synthetics.
TRUE COLORS OF “DALMATIAN JASPER”

Dalmatian stone samples examined in this study reveal a spotted appearance connected with the presenceof alkali amphiboles disseminated through feldspar-quartz matrices. Left: A rough block-shaped specimenmeasuring 1.5 × 1.5 × 1 cm. Right: A polished bracelet (1 cm bead diameter) alongside a pendant measuring 3 cmin length. Photos by Tomasz Powolny.
The decorative gemstone known in the trade as “dalmatian jasper” due to its black spots (identified as arfvedsonite) is not widely discussed in the published literature. Tomas Powolny and Magdalena Dumańska-Słowik investigate the stone’s mineralogical composition and properties. On the basis of the study, they suggest the use of “dalmatian stone,” as the material does not meet the gemological definition of jasper.
THE COLOMBIAN EMERALD INDUSTRY: WINDS OF CHANGE

Colombian emerald-producing areas such as Muzo have a long tradition of independent mining. The hope of finding the stone that will change their lives is a strong motivator for miners, but bringing them into a formal system is challenging. Photo by Andrew Lucas.
Emerald mining in Colombia dates back more than a thousand years. Yet its greatest opportunities may still lie ahead, as multinational companies invest in the industry as transparency and traceability come to the forefront. In this field report, an expedition led by Colombian gemologist Darwin Fortaleché documents the recent changes in the country’s mine-to-market emerald industry.
LAB NOTES

A Brazilian kimberlite yielded a 50.8 ct rough type Ia diamondwith a dodecahedral habit, the result of resorption. Right: This 20.1ct round brilliant with I color was cut from the Brazilian rough.
Updates from GIA’s labs include reports on a high-quality diamond from Brazilian kimberlite, synthetic overgrowth on a flux-heated ruby and a beryllium-diffused sapphire, and separation of synthetic melee from natural diamond using GIA’s iD100 screening device.
MICRO-WORLD

Reminiscentof a flower in a rainstorm,this inclusionscene has been dramaticallyenhanced usingmodified Rheinberg illuminationto accentuatea growth blockageand thin-film rosettewithin a sapphire fromElahera, Sri Lanka.Photomicrograph byJonathan Muyal; fieldof view 1.34 mm.
G&G’s photomicrography section features a flower-like inclusion in a Sri Lankan sapphire, silvery rutile inclusions in quartz, and fluorite hosting eye-visible barite inclusions.
GEM NEWS INTERNATIONAL

These sapphires (0.64–8.27 ct) are from Antangand Gombe, in northern Nigeria. Photo by ShunsukeNagai.
The Fall GNI section includes an update on Mozambique ruby mining, an analysis of blue-green pyrope-spessartine with high vanadium, and an examination of sapphires reportedly from new sources in northern Nigeria. Source: GIA @topic:4


Title: Fall 2015 G&G: Trapiche Emeralds, Synthetic Diamonds and a Large Diamond Source Abstract: The lead article in this issue is an in-depth study on the geological formation and growth of Colombian trapiche emeralds. The cover photo shows a 58.83 ct. crystal specimen (left) and a 22.74 ct. cabochon (right), both displaying the material’s signature six-rayed pattern, from the renowned Peñas Blancas emerald region. The host rock, seen in the background, is carbonaceous shale containing veins of calcite, pyrite and minute crystals of low-grade emerald. Photo by Robert Weldon/GIA, courtesy of Jose Guillermo Ortiz and Colombian Emeralds Company, Bogota.

A report on Colombia’s unique trapiche emeralds is the cover feature of the fall 2015 issue of Gems & Gemology (G&G), which also offers an analysis of large synthetic diamonds produced in Russia and a detailed look inside the Letšeng Diamond Mine in Lesotho (the leading source for mega-sized diamonds).
Colombian Trapiche Emeralds: Recent Advances in Understanding Their Formation

Colombia’s trapiche emeralds show a distinct pattern that resembles a wheel with six spokes. They are found only in the black shales of the country’s western emerald zone near the legendary mines of Muzo, Quiopama and Coscuez.

These trapiche emeralds, all from Peñas Blancas, range from 5.09 to 22.74 carats. Photo by Robert Weldon/GIA. Courtesy of Jose Guillermo Ortiz, Colombian Emerald Co.
The researchers, Dr. Isabella Pignatelli, Gaston Giuliani, Daniel Ohnenstetter, Giovanna Agrosì, Sandrine Mathieu, Christophe Morlot and Yannick Branquet, performed spectroscopic and chemical analyses on the samples to determine how they formed within their geological setting. They determined that super-pressurized fluid within the black shale helped grow the emerald seed crystals and provided a unique growth environment for them to form into trapiches.
Large Colorless HPHT-Grown Synthetic Gem Diamonds from New Diamond Technology, Russia

In the past five years, the vast majority of synthetic diamonds appearing in the gem market have been manufactured by the Chemical Vapor Deposition (CVD) process, which has been viewed as more efficient than the older High Pressure, High Temperature (HPHT) method, especially for colorless stones.

A Russian manufacturer, New Diamond Technologies, however, has introduced a line of large HPHT grown colorless synthetics and offered 44 samples to GIA for analysis.

As-grown HPHT diamond single crystals produced using a simple Fe-based solvent with Al as a nitrogen getter. The sample on the far right is the largest, weighing 1.40 ct. Photo courtesy of New Diamond Technology.
GIA researchers Ulrika F.S. D’Haenens-Johansson, Andrey Katrusha, Kyaw Soe Moe, Paul Johnson, and Wuyi Wang analyzed the samples using a combination of spectroscopic and gemological techniques to characterize the quality of the material and determine the means of distinguishing them from natural, treated and alternative laboratory-grown diamonds.

These samples had weights ranging from 0.20 to 5.11 carats, color grades from D to K, and clarity grades from IF to I2. Importantly, 89% were classified as colorless (D-F), demonstrating that HPHT growth methods can be used to routinely achieve these color grades.
Letšeng’s Unique Diamond Proposition

The Letšeng-la-Terae diamond mine in Lesotho is the world’s most consistent source of type IIa diamonds (those with exceptionally low nitrogen content), which account for about one-fourth of its production. The mine claims six of the 20 largest diamonds ever discovered: 478, 493, 527, 550, 601 and 603 carats. The largest of these, the Lesotho Promise, was found in 2006 and sold to London jeweler Laurence Graff for $12.4 million.

This remote village, deep in the Maloti Mountains near the Letšeng mine, is primarily dedicated to agriculture and sheep herding. Villagers also form the workforce for the diamond mine. Basuto ponies, such as the one seen here, are esteemed for their speed and surefootedness in the steep, rocky mountain passes. Photo by Robert Weldon/GIA.
The report by Russell Shor, Robert Weldon, A.J.A. (Bram) Janse, Christopher M. Breeding and Steven B. Shirey, also notes that Letšeng’s diamonds are unusual in that a majority are dodecahedral in form, which are very rare in other sources. Despite its bounty, Letšeng has had a difficult history because its ore grade is extremely low – about 2 carats per 100 tonnes and was not economic until recovery technology and diamond prices improved to allow profitable operation.
Origin Determination of Dolomite-Related White Nephrite through Iterative-Binary Linear Discriminant Analysis

Determining the origin of nephrite jade always has been difficult using standard gemological properties and observations. The authors, Zemin Luo, Mingxing Yang and Andy H. Shen, sampled nephrite jade from eight different dolomite-related deposits in eastern Asia.

This ancient pendant was discovered in the tomb of Marquis Yi, ruler of Zeng State during the Warring States period (ca. 475–221 BC). © Hubei Provincial Museum.
The authors used a new statistical analysis method based on linear discriminant analysis (LDA) and trace-element data from laser ablation−inductively coupled plasma–mass spectrometry (LA-ICP-MS), to achieve significantly improved origin determination (an average of 94.4% accuracy) for these nephrite samples. This technique could be applied to other gemstones to determine their geographic origins.
Lab Notes

This section of G&G features a discussion on unusual graining structure in a very light pink diamond with a uniform color plane intersecting with a cone of strain that fit perfectly into a colorless hole; an HPHT treated yellow diamond whose treatment was discovered by spectroscopic analysis; and an emerald with strong color zoning along the pavilion facets that demonstrates the importance of proper orientation and cutting. Other lab notes include a look at irradiated green-blue CVD synthetic diamonds that are the product of new growth technology; a natural green jadeite carving with areas that had been dyed green; and an examination of three large, natural abalone pearls.

Three unique abalone pearls are shown alongside a typical 12 mm golden South Sea bead-cultured pearl for comparison.
Micro-World

The Micro World section shows a Fancy Intense purplish pink diamond with an intricate geometric pattern of planar cracks and strain-induced bodycolor; an otherwise colorless rough diamond that has an eye-visible bluish-green stain near the surface caused by radiation; blue octahedral crystal inclusions within helidor cabochons that are determined to be gahnite, a rare zinc-rich member of the spinel group; and a trapiche pezzottite reportedly found near the Thai-Myanmar border.

Between crossed polars the diamond shows high-order interference colors consistent with the strain causing the cleavage network along the octahedral planes. Photomicrograph by Jonathan Muyal; field of view 0.62 mm.
Other features in this section include glassy melt inclusions in alluvial Montana sapphires, molybdenite inclusions in colorless topaz, and a lighting technique from gemological microscopy, Modified Rheinberg Illumination, that provides false-color contrast to enhance inclusion scenes. Source: GIA @topic:1


Title: Perles de Culture de la Mer de Cortez: Les Belles Inconnues [Unknown Beauties: Cultured Pearls from the Cortez Sea] Abstract: The first part of the article gives a historical survey of pearls from the Sea of Cortez (Gulf of California), followed by an account of the actual situation. Black pearls and nacre have been known since pre-Columbian times and were much coveted in Europe after the Spanish conquest. In the 16th century, the coastal city of La Paz became the main commercial center for nacre and pearls. The most famous pearl from this source is “La Peregrina,” a 203.8-grain gem last owned by Elizabeth Taylor, and John Steinbeck’s story “The Pearl” also takes place there.

While nacre production was predominant in the first half of the 19th century, black pearls were very much in fashion in the middle of the century. From 1893 to 1914, José Gourieux was the first to cultivate Pteria mazatlanica black-lipped oysters from La Paz for their nacre. He produced about five million oysters per year, of which 10% contained natural pearls. Although these were only a by-product, they led to a sharp decline in pearl diving. In 1914, the plant farm was destroyed during the Mexican revolution. The appearance of artificial substitutes for nacre, overfishing of the oyster banks, and a mysterious infection of the oyster larvae in 1939 finally led to the prohibition of all pearl diving a year later.

After attempts to renew pearl cultivation in the 1960s and 1970s, which failed largely because of political influences and the commercial success of black Tahitian pearls, three students of the Monterrey Institute of Technology and Superior Studies set up a small farm on the campus at Bacochicampo Bay in Guaymas. Their intent was not the industrial production of pearls but the development of environmentally sound and “oyster-friendly” methods of cultivation, which is why the oysters are implanted only once and harvests are small. The 2011 harvest consisted of 1,783 pearls, or 1.7 kg, as compared to 50 tons of Akoya pearls, 11 tons of South Sea pearls, 12 tons of Tahiti pearls, and 1,800 tons of Chinese freshwater pearls.

The other pearl-producing oyster of those waters, the rainbow-lipped Pteria sternia, yields black pearls with many different overtones. The young oysters are all harvested in the sea. Before the implantation of nuclei, the oysters are X-rayed. Some 3% contain natural pearls, and these oysters are not implanted. The pearls are sold as “natural,” though purists would dispute this description. The oysters with nuclei are cultivated for 18–24 months. The diameter of the cultured pearls ranges from 8–12 mm (3.2–4.8 inches), the thickness of the nacre from 0.8 mm–2 mm (0.3–0.8 inches). The pearls are black and very iridescent and show various strong overtones, including red (“cranberry”). Their luster is somewhat more silky than that of the Tahitian pearls. Unlike most other cultured pearls, they are not treated in any manner, except for rinsing with water. They show a pink to red UV fluorescence, which is characteristic of pearls from the Sea of Cortez.

The future is uncertain, however. The volume of larvae has dropped significantly because of global warming effects, damage to the oyster cages from fishing boats, and the fragility and sensitivity of Pteria sternia.

Abstracted by Rolf Tatje Source: GIA @topic:5


Title: Spring 2004 G&G Book Reviews Abstract: “Pearl Buying Guide: How to Evaluate, Identify and Select Pearls & Pearl Jewelry”
By Renée Newman, 134 pp., illus., publ. by International Jewelry Publications, Los Angeles, 2004. US$19.95

“Faszination Turmalin”
By Paul Rustemeyer, 309 pp., illus., publ. by Spektrum Akademischer Verlag, Heidelberg, Germany, 2003 (in German). 99.95

“Flux-Enhanced Rubies and Sapphires”
By Ted Themelis, 48 pp., illus., publ. by Gemlab Inc., Bangkok, 2004. US$20.00

“Tesouros de Arte e Devoção [Treasures of Art and Devotion]”
By Artur Goulart de Melo Borges, 336 pp., illus., publ. by Fundação Eugénio de Almeida, Évora, Portugal, 2004 (in Portuguese). 40.00

“Glitter & Greed: The Secret World of the Diamond Carte”
By Janine Roberts, 374 pp., illus., publ. by The Disinformation Co., New York, 2003. US$22.95

“Minerals of Nevada”
By Stephen B. Castor and Gregory C. Ferdock, 560 pp., illus., publ. by the University of Nevada Press, Reno, NV, 2003, US$75.00

To view the full section, download the PDF above. Source: GIA @topic:10


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

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

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

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


Title: Book Review: Jeweler’s Enameling Workshop: Techniques and Projects for Making Enameled Jewelry Abstract: By Pauline Warg, paperback, 160 pp., publ. by Interweave, Fort Collins, Colorado, 2016, $16.99.

Enameling is a form of art that many cultures have practiced for centuries, all around the world. If you happen to be a jeweler, you’ve most likely had some exposure to the process in your career, whether facing a challenging request for repair, using the technique to enhance a design, or simply admiring the delicate, colorful work. If you are a jewelry enthusiast but not a maker, you’ve most likely seen the art form but perhaps not realized the minutia behind the beauty.

Why do craftspeople enamel jewelry, and what exactly is enameling? you may wonder. Pauline Warg’s new book, Jeweler’s Enameling Workshop, will help answer these questions. Flipping through the book, we are regaled with page after page of answers: full-size pictures that show the vibrant colors created with the enameling process. The author’s account in the introduction deepens our understanding of why. Jewelry metals can be very monochromatic, and Ms. Warg writes “I love being able to add color to my work without necessarily using gemstones.”

The title’s reference to “workshop” points to the second question: what is enameling? We think of attending a workshop, where we’ll learn hands-on practice, and also of the jeweler’s workspace, where we get a glimpse of interesting tools and various stages of enameled pieces. Ms. Warg has delivered a 160-page resource detailing the intricate art of fusing glass to metal. The book includes essential information, step-by-step project instructions, links to other well-known authors and books, and a list of resources and supply houses.

The book’s first section, "Enameling Basics," provides a wonderful general introduction to enameling that is both easy to read and informative. It includes enough of the science behind the methods for the reader to understand what is happening, but not so much as to bog down the reader. For those who are inspired to pursue enameling, there are other, more process-intense publications that include the expanded science; that is not this book’s intent.

Another key aspect of the first section is a thorough overview of the tools and setup necessary for enameling. In general, jewelry making is a tool-rich activity, and enameling takes the richness to a whole new level. Having basic jewelry-making tools is not enough to start enameling in your studio, and the author does a good job outlining the difference between the two. Further, she is very thoughtful about listing not only what tools and supplies are needed, but also the skills necessary to complete a project. Instructions on how to use the tools, process photos, and troubleshoot, and reminders of general safety concerns guide readers through the methods to create enameled pieces. Lastly, and most importantly, after reading the first section we are left inspired and ready to get busy in our “workshop.”

The main body of the book, titled "Projects," features a series of 20 enameled jewelry projects with step-by-step instructions. The way the author created connections between terms, similar processes, and sections where expanded explanations can be found is very well thought-out. Not only is it like having an instructor present, but it also helps the reader navigate without having to reread similar instructions in each section.

Here and there throughout the book an entry-level jewelry maker may feel a little lost. A few pages include written descriptions of tools that, while standard in a well-used jeweler’s shop, are not everyday knowledge. Although the book is described as appropriate for someone wholly new to both enameling and jewelry making, this is a tall order for one publication. More than likely the reader will need some prior courses or additional books to understand some of the instructions.

Another area that may leave a beginning enamelist feeling behind is the instruction of loading pieces into the kiln for firing. Balancing a small piece of metal coated with ground glass on top of a metal trivet, carefully placing these on a wire rack, and then successfully balancing the three items on a long-handled firing fork while gently placing them into a 1450°F kiln is a precarious maneuver! While Ms. Warg does outline the method, not including a full-size image of the practice in the extensive photos is an oversight, considering it is such an essential part of the enameling process. The author does, however, carefully outline the different types of kilns, as well as the difference between an enameling, or jeweler’s, kiln and a top-loading ceramicist’s kiln.

The flow of the book from one section to another is well thought-out and easy to follow, transitioning nicely from entry-level enameling to more complex projects. The author very thoroughly covers the volume of information necessary to teach how to enamel, while also taking into account how to make a lovely piece of jewelry.

Jeweler’s Enameling Workshop is a great pick for any beginning to advanced jeweler. Having a copy on your bench will inspire you to get working and to start dreaming about how to add beautiful color to your jewelry designs. Source: GIA @topic:10


Title: Summer 2006 G&G Book Reviews Abstract: “The Heartless Stone: A Journey through the World of Diamonds, Deceit and Desire”
By Tom Zoellner, 294 pp., publ. by St. Martin’s Press, New York, 2006. US$24.95

“Making the Most of Your Flex-shaft”
By Karen Christians, 96 pp., illus., publ. by MJSA/AJM Press and the Ganoksin Project, Providence, RI, 2006. US$34.95

“Charming: The Magic of Charm Jewelry”
By Deborah Alun-Jones and John Ayton, 112 pp., illus., publ. by Thames & Hudson Inc., New York, 2005. US$19.95

“Bedazzled: 5,000 Years of Jewelry”
By Sabine Albersmeier for The Walters Art Museum, 64 pp., illus., publ. by D. Giles Ltd., London, 2005. US$9.95

“Modernist Jewelry, 1930–1960: The Wearable Art Movement”
By Marbeth Schon, 227 pp., illus., publ. by Schiffer Publishing Ltd., Atglen, PA, 2004. US$69.95

To view the full section, download the PDF above. Source: GIA @topic:6


Title: Cloud Inclusions Causing Fancy Light Blue Color in Diamond Abstract: Figure 1. The 2.20 ct Fancy Light grayish blue diamond. Photo by Jian Xin (Jae) Liao.
The most common cause of blue color in diamond is the incorporation of boron into the diamond crystal lattice (type IIb), such as the recently auctioned Cullinan Blue (Summer 2022 Lab Notes, pp. 216–217). Other causes of blue color in diamond are hydrogen-related absorption (C.H. van der Bogert et al., “Gray-to-blue-to-violet hydrogen-rich diamonds from the Argyle mine, Australia,” Spring 2009 G&G, pp. 20–37) and irradiation, either natural or artificial. Artificial irradiation using an electron beam is a common diamond treatment (Winter 2020 Lab Notes, pp. 517–518).

Figure 2. The mid-infrared spectrum of type IIb diamond compared to the 2.20 ct grayish blue diamond, which was type IIa with no boron or hydrogen-related features. Spectra are offset vertically for clarity.

Figure 3. The UV-Vis-NIR spectrum of the 2.20 ct grayish blue diamond compared to a UV-Vis-NIR spectrum with typical hydrogen absorbance (notably at ~545 nm) and broad bands at ~700–800 nm, causing the desirable violet to blue colors. The inset shows typical colors associated with this absorbance spectrum. The red trace is also inconsistent with type IIb absorption. With a slight rise to higher energy, a yellow color is expected. Spectra are offset vertically for clarity. Inset photo by Robert Weldon.
Recently submitted to the New York laboratory for colored diamond grading service was a 2.20 ct Fancy Light grayish blue diamond (figure 1). Compared to the Cullinan Blue, which was graded as Fancy Vivid blue on GIA’s color grading scale, this diamond was type IIa (i.e., no boron) (figure 2). In addition to the absence of boron-related impurities, this diamond lacked any hydrogen-related impurities (observed in the ultraviolet/visible/near-infrared spectrum in figure 3) (van der Bogert et al., 2009) or any GR1-related color centers, thus ruling out these major causes of blue color in diamond. Instead, the UV absorption for the 2.20 ct diamond was similar to what would be expected for a yellow type Ib (isolated nitrogen) diamond (figure 3).

Figure 4. Fine milky cloud inclusions are responsible for the natural blue color of the type IIa diamond, shown in darkfield illumination. Photo by Paul Johnson.
The diamond was heavily included with fine cloud-like inclusions, giving it a milky appearance (figure 4). Clouds, sometimes hydrogen-related, often cause gray, brown, black, or even white color in natural diamonds (S. Eaton-Magaña et al., “Natural-color fancy white and fancy black diamonds: Where color and clarity converge,” Fall 2019 G&G, pp. 320–337). In this case, the cloud micro-inclusions caused Rayleigh light scattering, creating a desirable blue color and not the expected yellow color resulting from a slight rise in absorption from lower to higher energy.
Based on these cloud inclusions, the diamond was given a final color grade of Fancy Light grayish blue, a natural origin of color, and an I3 clarity grade. Source: GIA @topic:4


Title: Near-Colorless Melee-Sized HPHT Synthetic Diamonds Identified in GIA Laboratory Abstract: Figure 1. These six near-colorless round brilliant melee, ranging from 0.01 to 0.005 ct, proved to be HPHT synthetic diamonds. Photo by Nuttapol Kitdee.

              With significant development in diamond treatments and synthesis over the last decade, the trade has serious concerns about treated and/or synthetic material mixed with natural melee-sized stones. The mixing of treated and synthetic diamonds with yellow natural melees was previously reported (Winter 2014 Lab Notes, pp. 293–294; Spring 2015 Lab Notes, pp. 64–65). In order to ensure consumer confidence, it is essential to screen melees so as to distinguish all treated and synthetic goods.

Recently, the Bangkok lab had the opportunity to examine six melee-sized specimens submitted for synthetics and treatment screening. The transparent, near-colorless round brilliants ranged in size from 0.005 to 0.01 ct (figure 1). Microscopic observation revealed no obvious inclusions. Between crossed polarizing filters, very little or no strain was observed. Infrared absorption spectra showed that four of the samples were type IIa diamonds with no detectable defect-related absorption, while the other two were type IIb diamonds accompanied by uncompensated boron showing moderately strong absorption at approximately 2800 cm–1. Photoluminescence spectra obtained at liquid-nitrogen temperature with 514 and 633 nm laser excitations revealed an emission doublet of the negatively charged silicon split-vacancy defect [Si-V]– at 736.6/736.9 nm for five of the samples, while 830 nm laser excitation showed an emission doublet at 883.0/884.7 nm owing to a nickel-related defect for all six samples (figure 2). DiamondView imaging revealed either blue or green fluorescence, together with characteristic growth features of HPHT synthesis, as seen in figure 3. Strong blue phosphorescence was also observed for all six samples. These gemological and spectroscopic features confirmed that the specimens were grown by HPHT synthesis.

Figure 2. Photoluminescence spectra at liquid-nitrogen temperature of a small near-colorless HPHT synthetic diamond. The spectra displayed emission peaks at 736.6 and 736.9 nm related to a [Si-V]– defect (left, 514 nm laser excitation) and at 883.0 and 884.7 nm associated with a Ni-related defect (right, 830 nm laser excitation).

Figure 3. This DiamondView image of one sample (third from the left in figure 1) shows the characteristic growth features of HPHT-grown synthetic diamonds. DiamondView image by Charuwan Khowpong.
To the best of our knowledge, this is the first examination of near-colorless HPHT synthetics of these sizes by a gemological laboratory. Discovery of these HPHT synthetic diamond melee reaffirms the need to screen the huge volume of near-colorless melee currently in the trade. Source: GIA @topic:4


Title: Gray-To-Blue-To-Violet Hydrogen-Rich Diamonds from the Argyle Mine, Australia Abstract: The Argyle diamond mine is the only known source of type IaB hydrogen- and nitrogen-rich diamonds colored gray to blue to violet. Twenty such diamonds were studied to investigate the relationships between their spectroscopic characteristics and color grades. The unusual color is the result of broad absorption bands centered at ~520–565 nm and 720–730 nm. A pronounced 551 nm band is superposed on the 520–565 nm feature. Spectral deconvolution of this feature suggests that it may be a composite, including H-related absorptions at ~545 and 563 nm and bands at 520–530 and 551 nm. The near- and mid-IR regions exhibit strong absorptions, including those related to H and N, many of which become more intense with increasing color saturation. The PL spectra exhibit peaks associated with nickel-related defects, which may play an important role in the coloration of the more violet diamonds in this group. H-rich gray-to-blue-to-violet diamonds, which are not known to be treated, can be readily separated from similar-hued diamonds that may be HPHT enhanced or synthetic.

	DATA DEPOSITORY

Supplemental Material
	Spring, 2009 Source: GIA @topic:4


Title: Treated HPHT Laboratory-Grown Diamond with Dramatic Color Zoning Abstract: Figure 1. This 2.20 ct Fancy Deep brownish orange treated HPHT-grown diamond owes its distinctive appearance to multiple defect concentrations created within the various growth sectors. Photo by Diego Sanchez.

Figure 2. The square-shaped cubic {100} growth sector appears pink when viewed through the table (left) and more of a purple color when viewed through the pavilion (right). The surrounding regions appear predominantly yellow due to the presence of single nitrogen. Photomicrographs by Nathan Renfro; fields of view 4.23 mm and 4.50 mm.
Recently, the Carlsbad laboratory examined a 2.20 ct laboratory-grown diamond that received a color grade of Fancy Deep brownish orange (figure 1). Spectroscopic analysis indicated high-pressure, high-temperature (HPHT) growth methods and subsequent irradiation and annealing to create nitrogen vacancy centers. Infrared absorption spectra collected from the entire stone identified it as type Ib with a concentration of ~5 ppm of single isolated nitrogen. The diamond was distinctive because of a pronounced pink square under the table facet within the cubic {100} sector. The other major growth sectors (e.g., {110}, {111}) surrounding the central cubic sector appeared yellow due to single isolated nitrogen. The pink growth sector displayed pronounced reflections when viewed through the pavilion facets and had more of a purple color (figure 2).

Figure 3. Room-temperature Vis-NIR absorption spectra were collected using a reflectance probe to document the absorption differences between the pink central region and the surrounding areas. The red trace shows a pronounced absorption associated with NV– along with Ib (i.e., single nitrogen) absorption. The yellow trace also shows Ib absorption along with a minor contribution of NV0 and small peaks associated with GR1 (741.2 nm) and nickel (883/884 nm). Spectra are offset vertically for clarity.
Visible/near-infrared (Vis-NIR) absorption spectra were collected from the center of the table using a reflectance probe positioned to show pink fluorescence. The probe was then repositioned toward the crown facets that did not show pink fluorescence (figure 3). The spectra from both areas indicated type Ib-related absorption at low wavelengths. Additionally, the pink color region was dominated by the NV– center (zero-phonon line, or ZPL, at 637 nm) and its associated sidebands, while the surrounding yellow regions had minor absorption from NV0 (ZPL at 575 nm). This difference in NV-related absorption shifts the transmission window from pink to yellow.
The uptake of single nitrogen is generally lower in {100} growth sectors than in {111} sectors (R.C. Burns et al., “Growth-sector dependence of optical features in large synthetic diamonds,” Journal of Crystal Growth, Vol. 104, 1990, pp. 257–279). However, the concentration of single nitrogen (necessary to ultimately create NV centers) can be increased within the cubic sector through lower growth temperatures (S. Satoh et al., “Differences in nitrogen concentration and aggregation among (111) and (100) growth sectors of large synthetic diamonds,” Science and Technology of New Diamond, KTK Scientific Publishers/Terra Scientific Publishing Co., Tokyo, 1990, pp. 351–355). It is possible that such growth conditions were used with this diamond in order to incorporate sufficient nitrogen within the cubic sectors, which were subsequently transformed to NV centers with treatment.

Figure 4. PL mapping using 532 nm excitation at liquid nitrogen temperature shows pronounced differences in defect concentrations based on growth sector. The NV– intensity (left, normalized to the diamond Raman line) is highest within {100} and much lower within the other regions. The normalized NV0 defect intensity (right) was detected throughout the diamond but was noticeably higher within {111} sectors.
Within the cubic sector, photoluminescence (PL) mapping showed a significantly higher concentration of NV– compared with the other major growth sectors (e.g., {110} and {111}), while the concentration of NV0 was lower (figure 4). The presence of donors, such as single nitrogen, can often shift the balance between neutral and negative NV centers so that NV– is enhanced in diamonds with single nitrogen (I.A. Dobrinets et al., HPHT-Treated Diamonds: Diamonds Forever, 2013, Springer-Verlag, Berlin). The presence of single nitrogen can be related to an elevated concentration of NV– within the cubic sector; however, in the {111} sectors, NV0 dominates over NV– despite the appreciable concentrations of single nitrogen. This can likely be attributed to the {111} sectors also preferentially incorporating boron. Although boron was not detected within the infrared absorption spectra for this stone, it is often present in HPHT-grown diamond, even at low concentrations. Since boron preferentially incorporates within {111} sectors (U.F.S. D’Haenens-Johansson et al., “Synthesis of diamonds and their identification,” Reviews in Mineralogy and Geochemistry, Vol. 88, No. 1, 2022, pp. 689–753), these acceptors could shift the charge balance within those areas, thus causing the preferential creation of NV0 over NV–.
PL mapping highlighted other pronounced differences between the growth sectors. The GR1 defect (V0) and TR12, an irradiation-related defect with ZPL at 469.9 nm, was highest in {110} and negligible in {100}. The nickel-related doublet at 883/884 nm was extremely high in {111} and negligible in {110} and {100}.
This HPHT-grown diamond is a notable example of growth techniques and treatment engineering producing a combination of defects that is visually interesting. The faceting approach, in which the pink growth sector was positioned under the table facet, served to enhance the dramatic appearance. Source: GIA @topic:4


Title: Diamondiferous Mantle Eclogite: Diamond Surface Features Reveal a Multistage Geologic History Abstract: Figure 1. Mantle eclogite xenolith (2.8 cm in longest dimension) consisting of clinopyroxene (green) and garnet (red-orange), with a partially exposed octahedral diamond. Photo by Annie Haynes. Gift of Mark Mauthner, GIA Museum no. 37511.
More than 99% of diamonds originally formed in the lithospheric mantle, the cold, rigid mantle that underlies continents, generally <300 km deep (T. Stachel and J.W. Harris, “The origin of cratonic diamonds – Constraints from mineral inclusions,” Ore Geology Reviews, Vol. 34, No. 1-2, 2008, pp. 5–32). In the lithospheric mantle, the two major rock types—and host rocks for diamond—are peridotite (>95 vol.%), composed predominantly of olivine, and eclogite (<5 vol.%), composed of iron-magnesium-calcium garnet and sodium-rich clinopyroxene. Eclogite is a high-pressure and high-temperature metamorphic rock that can form when dense oceanic crust subducts into the mantle beneath continents at convergent margins.
We cannot directly study the deep portion of the earth where diamonds form. Instead, geologists study diamonds themselves, as well as pieces of mantle rock that are transported to the surface as xenoliths by volcanic magmas such as kimberlite or lamproite. The authors have studied one such mantle eclogite xenolith, part of the GIA Museum collection (figure 1). This sample was recovered from a kimberlite in Russia and contained a partially exposed octahedral diamond. The exposed portions of the diamond had visible surface features, including trigons (figure 2).

Figure 2. Partially exposed diamond embedded in an eclogite xenolith, with positive and negative trigons on the octahedral face. A mineral is included within the diamond, visible through the octahedral face. Photomicrograph by Matthew Hardman; field of view 5.74 mm.
Trigons are inferred to be etch features that form after diamond crystallization, through interaction with fluids or melts either in the mantle source region or during transport to the surface (J.W. Harris et al., “Morphology of monocrystalline diamond and its inclusions,” Reviews in Mineralogy and Geochemistry, Vol. 88, No. 1, 2022, pp. 119–166). Trigons form exclusively on the octahedral faces of diamond and can have several different orientations. Positive trigons are oriented in the same direction as the octahedral face, and negative trigons have opposing orientation (figure 2). Positive trigons are very rare and may relate to interaction with carbon-oxygen-hydrogen-rich fluids at temperatures between ~800° and 1000°C at near-surface pressures (Z. Li et al., “Positively oriented trigons on diamonds from the Snap Lake kimberlite dike, Canada: Implications for fluids and kimberlite cooling rates,” American Mineralogist, Vol. 103, No. 10, 2018, pp. 1634–1648). Trigons with negative orientation are much more common. It has been shown experimentally that increasing water content in melts could be one cause for the change of a trigon from positive to negative (e.g., A.F. Khokhryakov and Y.N. Pal’yanov, “The dissolution forms of diamond crystals in CaCO3 melt at 7 GPa,” Russian Geology and Geophysics, Vol. 41, No. 5, 2000, pp. 682–687). Diamonds with coexisting positive and negative trigons are extremely rare (e.g., Harris et al., 2022) and may indicate that the diamond experienced a complex multistage history related to thermal or fluid changes after its formation.
Using the acquired infrared absorption spectrum, the authors identified the diamond as type IaAB, containing nitrogen in the A- and B-aggregated forms. When the entire xenolith was exposed to ultraviolet light, the diamond fluoresced blue due to N3 defects (three nitrogen atoms surrounding a lattice vacancy), consistent with the presence of nitrogen impurities.
The diamond also contained an unidentified mineral inclusion with visible iridescence (figure 2). Minerals included fully within diamond (which itself is an impermeable time capsule) represent pieces of the mantle source region present at the time of diamond formation. For this sample, the mineral was too deep within the diamond to conclusively identify it nondestructively. However, if the mineral inclusion could be extracted, its chemical composition might be very useful in reconstructing the geologic history of the host diamond, as well as that of the mantle rocks in which the diamond formed. Source: GIA @topic:1


Title: Natural Type IIa Diamond with Unusual Red Fluorescence Distribution Abstract: Figure 1. This 3.58 ct natural type IIa diamond with H color and SI2 clarity displayed a unique fluorescence pattern when exposed to deep-UV light. Photo by Diego Sanchez.
The Carlsbad laboratory received a natural type IIa diamond with some unusual characteristics. As part of the standard data collection, the diamond type was determined by Fourier-transform infrared (FTIR) spectroscopy and deep-UV fluorescence images collected using the DiamondView instrument. The DiamondView images revealed predominantly red fluorescence on one side of the diamond and blue fluorescence on the other. This 3.58 ct pear modified brilliant diamond had H color and received an SI2 clarity grade due to cavities, chips, and a feather (figure 1).

Figure 2. 514 nm PL spectra collected on the pavilion of opposite sides of the stone. The spectrum plotted in red corresponds with the red-fluorescing region, and the blue spectrum corresponds with the blue-fluorescing region, with Raman lines at 552 nm scaled as equal. Spectra are offset vertically for clarity. PL analysis spots are circled in the deep-UV fluorescence images. Images by Barbara Whalen.
Type IIa diamonds typically display a blue fluorescence pattern under deep UV as a result of “band A” fluorescence or the N3 defect in the stone (U.F.S. D’Haenens-Johansson et al., “Synthesis of diamonds and their identification,” Reviews in Mineralogy and Geochemistry, Vol. 88, No. 1, 2022, pp. 689–753). High amounts of nitrogen vacancy (NV) centers can cause red fluorescence in diamonds; however, this is rare in type IIa stones, as they are defined by nitrogen concentrations low enough to be undetectable by FTIR (Summer 2016 Lab Notes, pp. 189–190). The NV centers can be detected in a negative charge state (NV–, zero-phonon line at 637 nm) or a neutral state (NV0, zero-phonon line at 575 nm). Photoluminescence (PL) testing revealed much higher concentrations of both NV centers in the red-fluorescing region of the stone (figure 2). This distribution could have occurred if traces of isolated nitrogen were concentrated in one growth area of the stone.

Figure 3. False-color 532 nm PL map showing the Raman-normalized peak area of NV0 (left) and NV– (right). The maps were compiled from 47,040 spectra. The pronounced gradient in NV centers across the diamond resulted in the different fluorescence color observations (see figure 2 insets).
PL mapping using 532 nm laser excitation (figure 3) displayed the relative intensities of these defects, demonstrating the wide distribution of the NV centers in opposite sides of the table and crown facets of this diamond. Analysis of this interesting fluorescence feature demonstrated that nitrogen could have been distributed unevenly in a relatively pure type IIa diamond when it initially formed. Source: GIA @topic:4


Title: Gemological Analysis of Lightbox CVD-Grown “White” Diamonds Abstract: Figure 1. The 0.26 ct near-colorless CVD-grown diamond (left) has an internal inscription showing the Lightbox logo, composed of dual narrow lines. The logo is easily detected with a microscope (center) and clearly visible in the DiamondView image (right), in which the red fluorescence is due to nitrogen-vacancy centers. Also seen in the DiamondView image are subtle striations, additional evidence of the CVD origin. The outer square of the Lightbox logo measures 300 microns on each side. Photos by Robison McMurtry (left) and Sally Eaton-Magaña (center and right).
Lightbox, a De Beers company, has begun selling “white,” pink, and blue CVD laboratory-grown diamonds at a flat rate of $800 per carat. Through a third-party vendor, we recently had the opportunity to examine two such samples (0.24 and 0.26 ct) intended for setting in a pair of earrings. Both were near-colorless with color grades equivalent to G color and cut grades of Excellent and Very Good, respectively.
Both lab-grown diamonds had very few clarity characteristics. The 0.24 ct sample had a pinpoint in a bezel facet, and the 0.26 ct round (figure 1, left) had a feather in a star facet, both with VVS clarity. However, the grade-setting feature for both was the Lightbox logo, internally inscribed underneath the table facet (figure 1, center). As a result of the Lightbox mark, the clarity grade for both was reduced to VS. The laser-inscribed internal feature is reportedly made using technology developed by Opsydia (Gem and Jewellery Export Promotion Council, “De Beers to use Opsydia’s laser tech to inscribe lab-grown diamonds in Lightbox Jewelry,” https://www.gjepc.org/news_detail.php?id=4075). It is composed of dual narrow lines ~2.5 microns wide with a total area of 300 × 300 microns, positioned about 200 microns below the table surface.
Spectroscopic analysis showed both samples had very similar features that were consistent with previously analyzed CVD products from other manufacturers. IR absorption spectroscopy confirmed these samples as type IIa with no detectible single nitrogen at 1344 cm–1. Photoluminescence (PL) spectra showed that both had the 596/597 nm doublet, indicating that they were as-grown and not subjected to post-growth HPHT processing (S. Eaton-Magaña and J.E. Shigley, “Observations on CVD-grown synthetic diamonds: A review,” Fall 2016 G&G, pp. 222–245). Faceted, as-grown near-colorless CVD samples are less common since most manufacturers grow CVD layers quickly, but with a brown color, knowing that they can be HPHT treated to improve color appearance after growth. Approximately 75% of the CVD material in this color range examined by GIA has been HPHT treated after growth (S. Eaton-Magaña, “Summary of CVD lab-grown diamonds seen at the GIA laboratory,” Fall 2018 G&G, pp. 269–270).

Figure 2. This 514 nm PL spectrum collected on the 0.26 ct sample at liquid nitrogen temperature shows strong nitrogen vacancy centers at 575 and 637 nm and the 596/597 nm doublet, evidence of an as-grown CVD sample.
Through crossed polarizers, we observed very low birefringence compared with the majority of CVD-grown diamonds examined. Additionally, both samples showed very strong emission from nitrogen-vacancy centers by PL spectroscopy (figure 2), as well as visible red fluorescence using DiamondView imaging (figure 1, right), but there was no detectable fluorescence with long-wave UV. With careful DiamondView imaging, subtle CVD striations were visible through the table facet. In the DiamondView images, there were no apparent growth interfaces showing multiple growth events, and no apparent seed crystal remnants were observed. Also, PL spectroscopy of both samples showed very weak but detectable silicon-vacancy centers at 736.6/736.9 nm.
The Lightbox CVD lab-grown diamonds, due to their price point and manufacturer, will likely be highly visible in the trade. The pink and blue samples, as evidenced by De Beers’ literature, have an appearance that is unusual among natural-color diamonds and are unlikely to ever be perceived as a natural-color product. However, the colorless Lightbox samples are readily identifiable as CVD-grown diamonds by spectroscopic techniques, DiamondView imaging, and their distinctive internal inscription. Source: GIA @topic:4