Publish Year: 2016 Title: “Decorated” Jadeite Jade in the Chinese Market Abstract: Figure 1. A light-colored off-white jadeite pendant decorated with small green and brown jadeite attachments. Photo by Fen Liu.

Jadeite jade has long been popular in China, where it has profound cultural connotations. Fine-quality jadeite has the highest market value, especially the colorful and near-transparent pieces. Bright color zoning on a piece of jadeite will enhance its value; therefore, color-enhanced jadeite is available in the market. Filling and dyeing have been used for decades to modify jadeite’s color, but these methods can damage the texture of jadeite and reduce its value. A new method, cementing small colored jadeite attachments on the surface of jadeite ornaments, recently appeared in the Chinese jade market. Because the method does little or no damage to the main jadeite’s texture, we consider this an assembled stone.

Figure 1 shows three jadeite pendants decorated with small green and brown jadeite plates. These pendants were submitted to the Gem Testing Center of China University of Geosciences (Wuhan) for identification of species and treatment. They were tested by observation under microscope and ultraviolet lamp, infrared (IR) spectroscopy, and ultraviolet/visible (UV-Vis) absorption spectroscopy.

The background color and texture quality of the small plate attachments was similar to those of the main jadeite body, creating a harmonious overall appearance (again, see figure 1). The green color appeared to be floating on the surface and seemed to be detached from the base (figure 2, left), whereas the natural color zone of jadeite always changes gradually. Resin with accompanying bubbles was found in the space between the green attachments and the jadeite body (figure 2, right). Under the long-wave UV lamp, the resin in the contact region emitted strong blue-white fluorescence while the body did not fluoresce (figure 3).

Figure 2. Left: The green color on this jadeite appears to float on the surface and has a clear boundary. Field of view 5.50 mm. Right: Resin with bubbles fills the space in the contact area. Field of view 16.8 mm. Photomicrographs by Shufang Nie.

Figure 3. The resin in the contact region emits strong blue-white fluorescence under a
long-wave ultraviolet lamp. Photo by Fen Liu.

The IR reflection spectra of the green attachments showed typical jadeite features (figure 4, left). However, the IR transmission spectrum of the contact zone revealed peaks at 3058 and 3037 cm–1, indicating the stretching vibration of the benzene ring in resin (figure 4, right), which was used to attach the decoration. The blue trace in figure 4 is typical for jadeite without any treatment.

Figure 4. Left: The IR reflection spectrum of the jadeite decorations matches the typical spectrum for jadeite. Right: IR transmission spectra of the jadeite body (blue trace) and the green attachment zone (red trace). The blue trace is typical for natural jadeite without filling, while the 3058 and 3037 cm–1 peaks on the red trace are characteristic for resin, which was used to attach the colored jadeite plates.

The attachments all had a typical fibrous-granulous crystalloblastic texture without loosening or slagging. This implied they were natural jadeite that had not been subjected to acid washing or filling. The green color of the attachments was also natural, as shown by the UV-Vis absorption spectrum, which showed the 690 and 660 nm peaks induced by Cr3+. @topic:9


Publish Year: 2013 Title: Gem Olivine and Calcite Mineralization Precipitated from Subduction-Derived Fluids in the Kohistan Arc-Mantle (Pakistan) Abstract: Geochemical data in this study suggests that remobilized CO2 and H2O from a subducted island arc helped form the calcite + olivine-bearing veins in Kohsitan, Pakistan. The authors provide details on the geologic setting, mineralogy, and geochemistry of the vein assemblages, which can yield gem-quality olivine (peridot). The CO2 and H2O from island arc magmas and carbonates mixed with mantle fluids rich in Bo (as evidenced by ludwigite-vonsenite needlelike inclusions in olivine) as well as La, Ce, Ta, Cu, and Zn (from trace-element analysis). Fluid origin and emplacement are discussed at length, with emphasis on macro-geophysical mechanisms within the earth. Gem olivine production data and characterization of the rough were not provided.

Abstracted by Keith A. Mychaluk @topic:8


Publish Year: - Title: M.D. Hohenstine’s Gem Displays: The Process of Creating Popular Window Art with Loose Gemstones Abstract: M.D. Hohenstine frequently paid homage to the local theater and dance scene in his gemstone displays. This 1974 design honors the VaudVillities, a still-active Columbus group that bills itself as “the longest-running music and dance spectacular in the nation.” Photo by M.D. Hohenstine/Courtesy of Judith Allen Hall

Editor’s Note: Jeweler M.D. Hohenstine’s spectacular window displays  were a beloved tradition in downtown Columbus, Ohio from the 1920s until his death in 1976. The displays, consisting of hundreds of loose, natural gemstones arranged into a variety of shapes, patterns and figures, were changed every other week. Hohenstine photographed each of the 2,000-plus displays and turned them into slides that he used to educate fellow jewelers and gemologists. He gifted dozens of the slides to former employee and longtime family friend Judith Allen Hall when she began teaching. Hall donated the slides to GIA’s Richard T. Liddicoat Gemological Library and Information Center in 2016.

Here, she remembers the remarkable process Hohenstine followed to create fresh window art for his store for decades.

Mr. Hohenstine made a dozen opaque glass plates with matte surfaces and gilded wood frames. Each was about 10-12 inches in diameter. Some were round, others square; some were white, others were pale green. A couple of them had a small hole drilled in the plate. Under the plate was some sort of a small motor, and on top of the plate was a post that held the 10-ct. diamond upright so that it rotated and glittered.

He would begin by drawing the design on the plate with a soft pencil, and then open the desk drawer full of loose gemstones. With tweezers and an optivisor, he would painstakingly start putting the gems in place. The tables of brilliant cuts would be turned in certain directions to give the illusion of depth. All of the gems were simply laid on the plate – there was nothing to secure them.

It took six or more hours to complete the design, depending on its complexity. Customers could look in the curved window in front of the diamond room window to watch him work.

Hohenstine’s displays – including this bird’s nest scene with 202 diamonds, 238 garnets, 286 hessonites, 92 rubies, 11 pearls and one onyx – were a marvel of craftsmanship and logistics. None of the hundreds of gems on each design was secured to the display boards. Photo by M.D. Hohenstine/Courtesy of Judith Allen Hall
He was very inventive and created a way to photograph every design. A camera was mounted facing downward in a cabinet behind his desk in the diamond room, and it was exactly the right height to put the completed gem design in focus. All you had to do was slide the glass plate on the shelf, push the camera button, and it was done. Each slide contained the number of the design and the number and type of gems included in the design.

Once the design was completed and photographed, it was ready for Tuesday night window trim after the store closed. The left front window was about 90 to 100 feet from the diamond room, which seemed like a mile if you were carrying the plate – which was ever-so-slightly tilted, with the unsecured gems in place.

The left window had one-inch thick, bulletproof glass and a huge I-beam under it, so that street and foot traffic would not jar the design. The back glass lifted up when unlocked to give access to the window. The old design was very, very carefully removed and put on the showcase behind the window. Care was taken so that if there was any calamity getting the new one in place, the old one could be put back in the window.

When the new design was in place, Mr. Hohenstine would put on his optivisor and pick up tweezers and move any gem that might have been displaced. Then the frame was put in place, along with a little typed sign that would read something like: “This is the 1543rd design and contains 200 rubies and 56 emeralds.”

The old design was then carefully carried back to the diamond room, and the next day he would take it apart and put all the little gems back in their respective envelopes. @topic:6


Publish Year: - Title: Book Review: Arts of the Hellenized East: Precious Metalwork and Gems of the Pre-Islamic Era Abstract: By Martha L. Carter, Prudence O. Harper, and Pieter Meyers, 424 pp., hardcover, publ. by Thames and Hudson, London, 2015, $75.00.

	The Hellenistic period refers to the era between the death of Alexander the Great in 323 BC and the rise of ancient Rome circa 30 BC. The spread of Greek culture through Alexander’s invasion of eastern lands, from the Mediterranean basin to modern-day Pakistan, influenced many indigenous cultures of these regions and left a significant mark on the region’s history, arts, science, and literature.

	The al-Sabah Collection in Kuwait contains western and central Asian artifacts from the Bronze Age through late antiquity, including the Hellenistic period. Martha Carter concentrated her research on the Hellenistic silverwork and wrote Arts of the Hellenized East: Precious Metalwork and Gems of the Pre-Islamic Era, the sixth volume in the al-Sabah Collection series, with contributions from Prudence O. Harper and Pieter Meyers. The authors provide detailed descriptions for each item within the cultural and historical context of the era and the regions. The 400-page publication is further enhanced by 350 color images illustrating the objects. It is noteworthy that quite a few rare and important objects in the collection are documented for the first time.

	There are more than 400 objects of Hellenistic silverwork in the collection. These include bowls, drinking vessels, and dishes made out of precious metals, mainly gilded silver. Of the hundreds of objects in the catalogue, only nine items contain gemstones, four of which are royal seals and intaglios carved out of carnelian, chalcedony, and garnet. Two bowls and two small cups, both of gilded silver, are inlaid with red garnets. A Buddhist gold reliquary set with red garnets and a blue sapphire is created from sheets of gold. There are two garnets remaining in their original bezel setting along with another unidentified stone (recorded as coral or glass); however, the author indicates that the blue sapphire bead on the lid of the casket was a later addition. Nevertheless, the object stands out as unusual piece from a gemological point of view.

	This volume starts with a brief account of the ancient cultures of the region given within the context of their art traditions and perception of silverware at the time. Objects made from precious metals were favored for both their monetary value and their utility. The value of silverware was simply measured by its silver coin weight. Some researchers suggest that this was an important feature, as use of coinage was not extensive and silverware might have served as large denominational banknotes. The introduction concludes with a summary of the socio-political setting for eastern Hellenistic metalwork.

	The catalogue is followed by a chapter on technical examination of some of the silver objects in the catalogue by Dr. Meyer. In the acknowledgment, Dr. Carter conveys her efforts to authenticate the provenance of certain objects in the collection, as most are from politically unstable regions such as Afghanistan, where systematic excavations are almost impossible. She combines her stylistic expertise with Dr. Meyer’s metallographic analyses to verify the origin of objects found by individuals rather than experts. His scientific insight to the ancient silver sources, production, and the metal’s importance as a commodity is a wonderful source to the reader. The chapter gives a clear explanation on modern analytical techniques to determine method of manufacture, condition, ancient and modern repairs, and authenticity in the collection.

	The last chapter on ancient silver cleaning and conservation is an informative piece to the ancient art collectors, as it reveals the importance of stopping decay on ancient metalwork, especially while on display.

	Ancient art collectors, art historians, appraisers, and jewelers alike would highly benefit from this volume. Arts of the Hellenized East: Precious Metalwork and Gems of the Pre-Islamic Era is a masterfully written, rare catalogue full of informative chapters on Hellenistic art and metal work technology. @topic:6


Publish Year: 1990 Title: Gem-Quality Cuprian-Elbaite Tourmalines from São José Da Batalha, Paraíba, Brazil Abstract: Unusually vivid tourmalines from the state of Paraiba, in north eastern Brazil, have attracted great interest since they first appeared on the international gem market in 1989. This article describes what is known of the locality at this time, but focuses on the most striking characteristic of the se gem tourmalines: the unusual colors in which they occur. Quantitative chemical analyses revealed that these elbaite tourmalines contain surprisingly high concentrations of copper, up to 1.92. wt. % Cu (or 2.38 wt. % CuO). Their colors are due to Cu2 + or a combination of Cu2 +, Mn3 +, and other causes. Some colors can be produced by heat treatment, but most also occur naturally. @topic:9


Publish Year: 1988 Title: An Update on Color in Gems. Part 3: Colors Caused by Band Gaps and Physical Phenomena Abstract: The previous two articles in this series described the origins of color in gems that derive from isolated structures of atomic dimensions—an atom (chromium in emerald), a small molecule (the carbonate group in Maxixe beryl), or particular groupings of atoms (Fe2 +-0-Fe3 + units in cordierite). The final part of this series is concerned with colors explained by band theory, such as canary yellow diamonds, or by physical optics, such as play-of-color in opal. In the case of band theory, the color-causing entity is the very structure of the entire crystal; in the case of physical phenomena, it is of microscopic dimension, but considerably larger than the clusters of a few atoms previously discussed. @topic:8


Publish Year: 1987 Title: An Update on Color in Gems. Part 1: Introduction and Colors Caused by Dispersed Metal Ions Abstract: Studies concerning the origin of color in gem materials have grown in sophistication in recent years, so that much new information is now available about natural color and its possible modification by various treatment processes. This three-part series of articles reviews our current understanding of gemstone coloration. The first part summarizes the factors that govern the perception of color, from the source of light to the human eye, and then examines in detail the role of one color-causing agent, dispersed metal ions, in the coloration of many gem materials, including ruby and emerald. The second part will explore charge-transfer phenomena and color centers as the cause of color in gems such as blue sapphire and Maxixe beryl. The series will conclude with colors that can be explained using band theory and physical optics, such as the play-of-color in opal and the blue sheen of moonstone feldspars. @topic:3


Publish Year: - Title: Gem Olivine and Calcite Mineralization Precipitated from Subduction-Derived Fluids in the Kohistan Arc-Mantle (Pakistan) Abstract: Geochemical data presented suggests remobilized CO2 and H2O from a subducted island arc helped form the calcite + olivine-bearing veins in Kohistan, Pakistan. The authors provide details on the geologic setting, mineralogy and geochemistry of the vein assemblages, which can yield gem-quality olivine (peridot). The CO2 and H2O from island arc magmas and carbonates mixed with mantle fluids rich in Bo (evidenced by ludwigite-vonsenite needle-like inclusions in olivine) as well as La, Ce, Ta, Cu, and Zn (from trace element analysis). Fluid origin and emplacement are discussed at length with emphasis on macro-geophysical mechanisms within the earth. Gem olivine production data and characterization of the rough was not provided.

Abstracted by Keith A. Mychaluk @topic:2


Publish Year: 2004 Title: Fall 2004 G&G Book Reviews Abstract: “Blood from Stones: The Secret Financial Network of Terror”
By Douglas Farah, 225 pp., publ. by Broadway Books, New York, 2004. US$24.95

“Starting to Collect Antique Jewellery”
By John Benjamin, 191 pp., illus., publ. by Antique Collectors’ Club, Woodbridge, England, 2003. US$25.00

“Starting to Collect Antique Silver”
By Ian Pickford, 192 pp., illus., publ. by Antique Collectors’ Club, Woodbridge, England, 2003. US$25.00

“Within the Stone”
By Bill Atkinson, 180 pp., illus., publ. by Browntrout Publishers, San Francisco, CA, 2004. US$39.95

“Gems and Jewels: A Connoisseur’s Guide”
By Benjamin Zucker, 248 pp., illus., publ. by Overlook Press, New York, NY, 2003. US$60.00

“The Tourmaline”
By A. C. Hamlin, 107 pp., illus., originally publ. by James R. Osgood & Co., Boston, MA, 1873; republished by Rubellite Press, New Orleans, LA, 2004, US$75.00

“The History of Mount Mica”
By A. C. Hamlin, 123 pp., illus., originally publ. by Augustus Choate Hamlin, M.D., 1895; republished by Rubellite Press, New Orleans, LA, 2004, US$85.00

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


Publish Year: 2003 Title: Winter 2003 G&G Book Reviews Abstract: “Tiffany Flora & Fauna”
By John Loring, 256 pp., two vols., illus., publ. by Harry N. Abrams, New York, 2003. US$50.00

“Burma Ruby: A History of Mogok’s Rubies from Antiquity to the Present”
By S. K. Samuels, 254 pp., illus., publ. by S.K.S. Enterprises, Tucson, AZ, 2003. US$45.00

“Gems from the East and West: The Doris Duke Jewelry Collection”
By Janet Zapata, Ulysses Dietz, and Zette Emmons, 120 pp., illus., publ. by the Doris Duke Charitable Foundation, New York, 2003. US$27.50

“The Rings Book”
By Ole Johnsen, 439 pp., illus., publ. by Princeton University Press, Princeton, NJ, 2002. US$49.50

“Cultured Pearl: Charm of the Pearl”
By Shigeru Akamatsu, 179 pp., illus., publ. by Shinju Shinnbun Co., Tokyo, 2003 (in Japanese). 3,800¥

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


Publish Year: 2000 Title: Spring 2000 G&G Book Reviews Abstract: “Romance of the Golcondra Diamonds”
By Omar Khalidi, 127 pp., illus., publ. by Grantha Corp., Middleton, NJ, 1999. $39.95

“Ruby, Sapphire and Emerald Buying Guide”
By Renee Newman, 164 pp., illus., publ. by International Jewelry Publications, Los Angeles, CA, 2000. US$19.95

“Rough Diamonds: A Practical Guide”
By Nizam Peters, 172 pp., illus., publ. by the American Institute of Diamond Cutting, Deerfield Beach, FL, 1997. US$89.00

“Crystal Enchantments: A Complete Guide to Stones and their Magical Properties.”
By D. J. Conway, 343 pp., publ. by the Crossing Press, Freedom, CA, 1999. US$18.95

“Diamonds and Precious Stones”
by Patrick Voillot, 127 pp., illus., publ. by Harry N. Abrams, New York, 1998, US$12.95

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


Publish Year: - Title: An Archive of Excellence: The Richard T. Liddicoat Gemological Library Celebrates 25 Years Abstract: The Richard T. Liddicoat Gemological Library and Information Center at GIA's world headquarters, The Robert Mouawad Campus, in Carlsbad, California. Photo by GIA

                      700+ periodicals
1,800+ videos
57,000+ books
150,000+ photographs

The sheer magnitude of print, video and image resources available through the Richard T. Liddicoat Library and Information Center is astounding. From 31 different editions of philosopher Pliny's “Natural History” – including a copy published in 1496 – to George Frederick Kunz’s “Gems and Precious Stones of North America,” one of the most important works on gems, the library houses some of the rarest and most highly regarded books in gemological and jewelry history. What started humbly as a single bookcase has become the largest, most complete repository of its kind in the world and the first point of reference for those studying gems and jewelry.

GIA’s original library consisted of a handful of publications that GIA founder Robert Shipley loaned to students and staff. Over the years, the collection grew to include important books about gems and jewelry, trade journals and the latest gemological research, totaling 2,500 informally cataloged and stored volumes by 1980.

Richard T. Liddicoat, then-president of GIA, recognized the need and benefit of more professional attention to the Institute’s growing collection. He appointed Dona Dirlam, a diamond grader and former geology teacher, as librarian. Dirlam embarked on a decades-long effort to develop the library into the resource it is today. She began by opening the library to students and staff without an appointment, reorganizing and cataloguing the collection, and expanding the physical space and the staff.

“We needed more staff by the mid-1980s just to handle the growing number of phone calls requesting information,” said Dirlam. “The more you help people, the more they call back for help, and then tell other people.”

As more and more people outside the Institute learned about the indispensable resources available, the library continued to grow, and so did the importance of amassing a comprehensive collection.

GIA acquired the Sinkankas collection, which contains nearly every major work related to the study of gems and jewelry, in January 1988. Accumulated over 40 years by noted author and lapidary John Sinkankas and his wife, Marge, the collection added nearly 6,000 articles and 10,000 books, including works dating back to 1511 A.D., rare volumes and numerous editions in different languages. With the addition of the Sinkankas collection, the library became a resource unlike any other.

GIA held an inaugural celebration in August 1989 to formally dedicate the library to Liddicoat, the ‘Father of Modern Gemology,’ and to officially unveil the Sinkankas collection.

Nearly 300 guests attended the event, described by George Schuster in his 2003 book “Legacy of Leadership: A History of the Gemological Institute of America:”

August 21, 1989. It was a glittering summer night of champagne, laughter and honors, a black-tie evening of men in tuxedos and women in elegant gowns. It was a night important enough to attract hundreds of leading gem and jewelry industry figures to the Gemological Institute of America.

It was the night of the formal dedication of the Richard T. Liddicoat Gemological Library and Information Center, including the newly acquired, world-renowned Sinkankas collection.

It was the night of the official unveiling of what one writer called “the greatest collection of gemological literature ever assembled.”
…

During the official opening ceremony, guests heard firsthand accounts from Dirlam, Liddicoat, and Boyajian on the acquisition of the Sinkankas collection and what it meant to GIA and the gemological community. Another highlight was Sinkankas’s off-the-cuff comments on how he and Marge had created their personal library, including book-buying adventures in Europe, the Howes acquisition and his longtime relationship with GIA. Mayor James Conn presented [then-president] Bill Boyajian with a letter of commendation from the city of Santa Monica acknowledging GIA’s contribution to education in the community. At the end of the night, departing guests were handed reprints of Gems & Gemology’s Spring 1989 article on the Sinkankas collection.

Now, 25 years later, GIA’s library continues to grow and offer resources to the gem and jewelry industry, gem enthusiasts, students and the public. Library staff assisted more than 10,000 visitors, students and staff in 2013. It’s open to the public Monday through Friday, but you don’t have to be in California to take advantage of its resources. Experienced librarians also answer questions and offer reference for gem- and jewelry-related questions by email, mail, phone and fax, responding to more than 1,000 queries each year. You can also search the library catalog online and access all 80 years of Gems & Gemology, GIA's quarterly research journal, on the website.

For Dirlam, the goal of the library is simple.

“We want to make this library the archive of the international jewelry industry, and an important part of our mission to ensure the public trust in gems and jewelry.” @topic:6


Publish Year: 2023 Title: A Red Herring in a Red Garnet Abstract: Gas bubbles hide just beneath natural crystal inclusions in this garnet and glass doublet. Photomicrograph by Emily Jones; field of view 1.58 mm.
At first glance, a 2.54 ct round mixed-cut stone examined by the author presented itself as a natural red garnet. Microscopic inspection revealed a host of transparent crystals and widespread epitaxial needles, both typical inclusions for garnet. Upon closer inspection, however, some of the apparent “crystals” were recognized as gas bubbles, betrayed by their smooth spherical forms (see above). This distinction can be easily missed without careful examination under high magnification. Additional observations and testing conclusively identified the material as pyrope-almandine garnet fused with manufactured glass. As with most garnet-topped doublets, the garnet portion was cut to occupy the crown while the glass made up most of the pavilion so that the natural inclusions of the garnet top masked the telltale signs of manufactured glass beneath. @topic:3


Publish Year: 2013 Title: An Opal-Calcite Composite Abstract: Figure 1. This 8.54 ct cabochon was a composite of brown opal and white calcite. Photo by G. Choudhary.

              Composites assembled from opaque to translucent gem materials such as turquoise, chalcedony, and chrysocolla have become quite popular in recent years, as evidenced by the number of samples received for identification at the Gem Testing Laboratory in Jaipur, India. We recently examined a white-brown, translucent to opaque oval cabochon (figure 1) that turned out to be a composite featuring an unusual combination of gem materials.

The specimen weighed 8.54 ct and measured 18.03 × 13.12 × 4.63 mm. At first glance, it appeared to be a rock consisting of some brown and white mineral, but the presence of golden veins ruled out such a possibility, suggesting instead a manmade product. Closer inspection of the cabochon from all sides revealed four distinct areas—a colorless polymer, golden veins and patches, a brown mineral, and a white mineral—all showing a different surface luster (figure 2, left). At the base of the cabochon, individual grains of a white mineral were embedded in the colorless polymer, as well as golden areas comprised of fine flakes, composed of zinc (figure 2, right). These features were consistent with those observed in a composite material (e.g., G. Choudhary, “A new type of composite turquoise,” Summer 2010 G&G, pp. 106–113).

	Figure 2. Under reflected light, the cabochon’s luster varied across four distinct portions (left). Note the polymer vein at the center of the image and the parallel planes and cloudy inclusions at the top of the white portion. Some of the golden areas were comprised of fine flakes embedded in polymer (right). Photomicrographs by G. Choudhary; magnified 24× (left) and 48× (right).
Although the cabochon was recognized as a composite, its components had yet to be identified. Spot RIs of 1.56 and 1.45 were obtained from the white and brown portions, respectively. The white portion also displayed a large birefringence blink, typically associated with carbonate minerals such as calcite, while no blink was observed on the brown portion. Under long- and short-wave UV radiation, the cabochon remained largely inert, except for a weak whitish glow observed on the white portions. Furthermore, magnification of the white portion revealed cleavage planes, liquid films, white cloudy inclusions, and doubling, while the brown portion was milky with fine flaky inclusions.

Spot RIs and magnification identified the white portion as calcite and the brown portion as opal, but these tests were not sufficient to prove their identity. Raman spectroscopy of the white portion in the 200–2000 cm–1 range (using 532 nm laser) displayed many sharp peaks at 281, 482, 712, 1086 (the strongest), 1435, and 1749 cm–1; these  peaks are associated with calcite. Raman spectra of the brown portion displayed broad absorptions at around 400–500, 800, and 1000 cm–1; these did not display sharp absorption features other than a peak at 487 cm–1. These absorptions are associated with amorphous materials such as opal (opal-A), and the 487 cm–1 peak is associated with Si-O vibrations (e.g., C.J. Brinker et al., “NMR confirmation of strained ‘defects’ in amorphous silica,” Journal of Non-Crystalline Solids, Vol. 99, 1988, pp. 418–428).

Identification of this cabochon as a composite was straightforward, but the components were more difficult to detect. Although Raman spectroscopy identified the materials present, the use of these two substances for making a composite remains unclear. @topic:3


Publish Year: 2021 Title: In Memoriam: Jean Claude Michelou Abstract: Colored stone industry veteran Jean Claude Michelou was founder and longtime editor-in-chief of ICA’s quarterly, InColor. Photo by Vincent Pardieu.

The colored stone industry lost one of its true leaders with the passing of Jean Claude Michelou (see above) on May 3 at the age of 72. Mr. Michelou graduated from the London School of International Business and began selling emeralds in Colombia in 1977. The business he later established, Imperial Colors Ltd., specializes in rough buying, grading, and cutting of emerald, tourmaline, beryl, and sapphire. He relocated the company to Bangkok in 2018.
Mr. Michelou was active with the International Colored Gemstone Association (ICA), serving as a board member for 18 years and as vice president for 10 years. In 2004, he founded ICA’s quarterly magazine, InColor, and was its editor-in-chief until his retirement earlier this year. He was also a consultant for the United States Agency for International Development (USAID), the World Bank, and other agencies on developing standards for the colored stone industry. In addition, he served on the advisory board for the University of Delaware’s Gemstones and Sustainable Development Knowledge Hub and organized the World Emerald Symposiums held in Bogotá since 2015.
For more than a decade before his passing, Mr. Michelou had been deeply involved in several beneficiation projects in source countries, including the Swat Valley emerald deposits of Pakistan and a Nigerian sapphire mining venture. He shared his insights on supply chain transparency and beneficiation with G&G in the Spring 2018 issue (Gem News International, pp. 93–94). Over the years, Mr. Michelou was a valuable source of knowledge for this journal and a mentor to many young industry professionals. We extend our condolences to his family and friends. @topic:11


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

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

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

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

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

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

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

Don’t miss this chance to learn more valuable and exciting information from GIA’s top experts. Find out more about GIA’s Continuing Education Recognition Program. You can also contact the GIA Alumni Association at +1 760 603 4145 or email alumni@gia.edu. @topic:11


Publish Year: - Title: Echoes of the Edwardian Era Abstract: Diamonds, silver, gold, and tortoise shell sparkle in this period tiara. Courtesy of a Private Collection

                      Diamonds. Pearls. Platinum. Symmetry. This defined Edwardian Era jewelry – and it’s still is extremely popular with modern designers.

Take a step back in time to the Edwardian Era (1900 – 1915). The sun never set on the British Empire. England was flush with power and wealth. Tastemaker Edward VII was king. For the landed gentry, the Edwardian Era was a period of prosperity and privilege. Perhaps the Titanic, the most luxurious and largest ocean-liner of its time, best captured the spirit of the age with her First, Second, and Third Class cabins. The arts in Great Britain served a definite purpose during the Edwardian Era; they were frequently used to reinforce the class system. Architecture, for example, was symmetrical and orderly, which evoked power, stability, and status.

	Class divisions were everywhere – even at bath houses. The Victoria Baths in Manchester had separate entrances for first class males, second class males, and females.

		Jewelry was a preferred way to show one’s rank in society. Only the upper classes could afford it, and they advertised their wealth and position by wearing exquisite works.

		Robert Ackermann, Jewelry Manufacturing Arts instructor, Carlsbad, GIA.

	Platinum, diamonds, and pearls were the materials of choice. Garlands and triumphal laurel wreaths belonging to a conqueror’s crown were common themes. These regal materials and motifs spoke of the might of the British Empire and the importance of the wearer. Stately tiaras, pendants, necklaces, and chokers were not only the style of the day but also carried symbolic weight. For example, it was rude for a lady to wear taller tiara in the presence of a woman of higher rank. Diamonds were abundant in Edwardian jewelry due to the discovery of mines in South Africa in the 1880s. A ready supply of the gem was now available, and Britain’s aristocracy quickly fell in love with the glittering stone.

	Pearls dangle from this diamond and cat’s eye alexandrite cabochon pendant.
Pearls were also popular during the Edwardian Era, and were often showcased in a piece of jewelry. Drop a pearl in a bed of diamonds or set it in platinum, and Edwardians thought this blazingly white-hot combination to be the height of sophistication and elegance. Although many of the customs of the Edwardian Era may seem to be a part of the distant past, the international success of Downton Abbey, the television drama whose first season was set in Edwardian England, proves that we are still fascinated by the time. And if you look around a jewelry store, you’ll see that Edwardian jewelry continues to influence contemporary designers. @topic:6


Publish Year: 2007 Title: Natural Type Ia Diamond with Green-Yellow Color Due to Ni-Related Defects Abstract: Commonly seen in HPHT-grown synthetic diamonds with a green component, nickel-related defects were identified for the first time in a type Ia natural diamond with a strong green component. The 1.75 ct Fancy green-yellow diamond showed a strong peak at 1332 cm−1 in the IR absorption spectrum, strong absorption from the 1.40 eV center and the associated ~685 nm band in the Vis-NIR spectrum, and extremely strong emissions from Ni-related defects in the photoluminescence spectra—all of which proved that nickel was the primary cause of the green color. @topic:4


Publish Year: 2022 Title: The Discovery of Davemaoite, the CaSiO3 Perovskite, in a Diamond from Earth’s Lower Mantle Abstract: Figure 1. A typical coated diamond from Orapa. This is not the stone studied, but rather one from the same batch and locality with approximately the same color and size. Photo by George Rossman.
Common silicate minerals such as olivine and garnet convert to other phases when brought to great depths in the planet, where they are subjected to extreme pressures. It has long been thought that two of the most common phases at depth in Earth have the perovskite structure. They have long been known from experimental studies in which they have been called magnesium silicate perovskite (MgSiO3) and calcium silicate perovskite (CaSiO3). Only recently has the magnesium silicate perovskite been found in nature, in a meteorite, where it was characterized and named bridgmanite (O. Tschauner et al., “Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite,” Science, Vol. 346, 2014, pp. 1100–1102). More recently, the calcium silicate perovskite has been found in a diamond and sufficiently characterized to be given a mineral species name (O. Tschauner et al., “Discovery of davemaoite, CaSiO3-perovskite, as a mineral from the lower mantle,” Science, Vol. 374, 2021, pp. 891–894).
Diamonds are one of the few minerals that bring us samples of the minerals found in the deep earth. Diamonds serve as chemically inert and nearly volume-conserving hosts for these minerals, thereby allowing them to retain their composition and in some cases even their original structure. The examination of the inclusions in an 81 mg (~0.405 ct) octahedral diamond from Orapa, Botswana, has resulted in the discovery of the high-pressure form of CaSiO3 in the perovskite structure occurring as a natural mineral in the diamond (figure 1). This phase has been approved by the International Mineralogical Association with the name davemaoite, named in honor of Dave (Ho-kwang) Mao, for his contributions to understanding the deep-mantle geophysics and petrology of our planet.
Experimental studies in the laboratory have indicated that CaSiO3 assumes the perovskite structure at depths between 420 and ~2700 km. This phase, first synthesized in 1975 (L. Liu and T. Ringwood, “Synthesis of a perovskite-type polymorph of CaSiO3,” Earth and Planetary Science Letters, Vol. 28, 1975, pp. 209–211), is only thermodynamically stable at pressures greater than 200,000 atmospheres (20 GPa). Furthermore, the rate of back-conversion to low-pressure polymorphs is rapid if the pressure is lowered. Consequently, the natural mineral is unlikely to survive transport from the deep earth to the surface.

Figure 2. The polished slab of the diamond containing davemaoite showing the round spots where the grains were excavated for LA-ICP-MS analysis. Photo by Aaron Celestian.
Davemaoite was first identified and characterized within a diamond studied at the Advanced Photon Source at Argonne National Laboratory in Illinois, where an X-ray beam was focused to a 0.5 × 0.5 μm spot. Calcium-rich inclusions in the diamond were first located. Two inclusions, 4 × 6 μm and 4 × 16 μm in size, were examined with X-ray diffraction. They both produced a perovskite pattern. Their identity was further confirmed by infrared spectroscopy. Theoretically, a cubic perovskite has no Raman pattern, and none was obtained from these inclusions. The inclusions were next excavated from the surrounding diamond and analyzed with laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) (figure 2). Their composition corresponded to the calcium silicate perovskite.
Davemaoite is significant in Earth’s deep mantle because it acts as a host to many elements that are incompatible with upper-mantle minerals, fulfilling a role that garnet plays in the upper mantle. Davemaoite may be the most geochemically important phase in the lower mantle because it will act as a repository in which the radioactive, heat-generating elements thorium and uranium become concentrated. Calculations suggested that davemaoite was entrapped in the host diamond at pressures of at least 290,000 atmospheres and temperatures of at least 1400 K. These diamonds from Orapa are also noteworthy because in addition to davemaoite, a high-pressure form of ice was found as a solid inclusion within them where the diamond’s internal pressure was great enough to maintain the ice in the solid form, allowing it to be characterized as the new mineral species ice-VII (O. Tschauner et al., “Ice-VII inclusions in diamonds: Evidence for aqueous fluid in Earth’s deep mantle,” Science, Vol. 359, 2018, No. 6380, pp. 1136–1139). @topic:8


Publish Year: 2020 Title: Colorless to Near-Colorless Diamonds, Emeralds from Pakistan, a History of European Royal Jewel Sales, and More… Abstract: Welcome to the Fall Gems & Gemology! This issue offers an exciting glimpse into the world of D-to-Z diamonds, characterizes the inclusion features and chemical composition of emeralds from Swat Valley, and details the acquisition and auction of crown jewels by European royalty.
“An exciting glimpse into the world of D-to-Z diamonds…”
In the lead article, a GIA team led by Sally Eaton-Magaña and Christopher M. Breeding examines colorless to light yellow/brown diamonds with a “D-to-Z” color grade, which make up the vast majority of the world’s gem diamond trade. Because this group of mostly type Ia diamonds has not been subjected to HPHT decolorizing treatment or laboratory growth, researchers usually investigate their more rare diamond type counterparts. This study evaluates diamond type properties and grading quality factors of D-to-Z diamonds submitted to GIA in 2017 and sheds light on their unique geological formation story.
The second article comes from a team led by Hongshu Guo, a student at the School of Gemology, China University of Geosciences in Beijing. The authors present the gemological and geochemical details of emeralds (including trapiche emeralds) from Swat Valley in Pakistan.
In the third article, Russell Shor examines how European royal families acquired their crown jewels, which were later sold at important auctions. The most recent of these was Sotheby’s historic Bourbon-Parma auction in 2018, in which 10 of the lots once belonged to Marie Antoinette.
Next, Ling Liu and colleagues from the Gemmological Institute, China University of Geosciences in Wuhan characterize turquoise from China’s Hubei Province with a rare surface pattern of spots resembling raindrops. They identify the color origin and formation mechanism of this distinctive pattern.
The final article is a field report from Hạ Long Bay in northern Vietnam, where in late 2019 Nicholas Sturman and coauthors visited a shell nucleus manufacturing factory and two pearl farms, all managed by Orient Pearls (Bangkok) Ltd. The team observed how high-quality bead nuclei are fabricated and used to produce Vietnamese bead cultured pearls suitable for fine jewelry on a commercial scale.
Our regular features continue to highlight interesting gemological findings from around the world. In Lab Notes, discover how gem cutters cleverly use color zoning in alexandrite and closely spaced needles in diaspore to showcase phenomena, and how areas of dramatic fluorescence correspond to diamond defects and produce a “lightsaber” effect. Curiosities abound in the Micro-World section: epigenetic residue mimicking a fried egg, metal sulfide inclusions resembling trees, and ferrocolumbite posing as star cruisers. Gem News International reports on bead cultured pearls with embedded electronic devices and Maxixe beryl with an unusual violet color, among other exciting topics.
This issue also contains the list of winners from this year’s G&G Challenge quiz. Congratulations, and our special thanks to everyone who participated! @topic:2


Publish Year: 2014 Title: Round CVD Synthetic Diamond Over 1 Ct Identified in Hong Kong Lab Abstract: Figure 1. Left: This 1.20 ct CVD synthetic round brilliant had a color grade of L, a clarity grade of SI2, and a cut grade of Very Good. Right: The 6.7 mm specimen contained a few black inclusions with irregular shapes. Photos by Ping Yu Poon.

In the past ten years, CVD synthetic diamonds have showed significant improvements in quality and size (Martineau et al., Spring 2004 G&G, pp. 2–25; Wang et al., Winter 2003 G&G, pp. 268–283; Wang et al., Summer 2012 G&G, pp. 80–97). Their color and clarity can be comparable with top natural counterparts, but for the most part they are still small. CVD gem-quality synthetic diamonds over 1 ct are occasionally reported in the trade, usually in fancy shapes with limited depth.

Recently, a round-brilliant specimen, identified as a CVD synthetic diamond, was submitted to the Hong Kong laboratory for grading service. It weighed 1.20 ct (6.70 × 6.72 × 4.30 mm), with a color grade of L, a clarity grade of SI2, and a cut grade of Very Good. This specimen resembled well-cut natural round diamonds (figure 1, left), with a few black inclusions of irregular shape clearly observable under the microscope (figure 1, right).

Figure 2. The CVD synthetic diamond’s infrared absorption spectrum showed a weak peak at 1344 cm–1. This feature, attributed to the isolated nitrogen impurity, was responsible for the L color grade.
Infrared absorption spectroscopy identified it as type IIa. A very weak absorption at 1344 cm–1 was attributed to isolated nitrogen in the diamond lattice (figure 2). Based on the absorption intensity (0.014 cm–1) of this peak, the total concentration of isolated nitrogen was well below 1 ppm. Occurrence of trace isolated nitrogen was the major optical center responsible for the L color observed. No hydrogen-related absorption was observed at either 3107 or 3123 cm–1 using infrared absorption spectroscopy. Photoluminescence (PL) spectra at liquid nitrogen temperature with 532 nm laser excitation showed the [Si-V]– doublet emissions at 736.6 and 736.9 nm (figure 3), a characteristic feature of CVD synthetic diamond. Weak emissions from N-V centers at 575.0 nm and 637.0 nm were also recorded. Fluorescence images collected using the DiamondView showed green fluorescence with characteristic CVD growth striations (figure 4). All these gemological and spectroscopic observations, very similar to those of Gemesis specimens (Wang et al., 2012), confirmed this was a CVD synthetic diamond. It was annealed at high pressure and high temperature (HPHT) to improve its color appearance.

Figure 3. A photoluminescence spectrum collected at liquid nitrogen temperature using 532 nm laser excitation revealed a strong emission doublet at 735.6 and 735.9 nm, indicating a [Si-V]– optical center.

Figure 4. Observed in the DiamondView, the 6.7 mm synthetic diamond showed typical striations indicative of CVD growth. Image by Carmen Lo.
As this sample shows, CVD technology has reached a new milestone, with the growth of crystals thick enough to consistently cut well-proportioned round brilliants. It is highly likely that we will see more gem-quality CVD synthetic diamonds over 1 ct in the trade. @topic:4


Publish Year: - Title: Summer 2018 G&G: Diamonds Across the Spectrum, Byzantine Garnet, and Sapphires from Yogo Gulch Abstract: For more than 120 years, Yogo Gulch in central Montana has been one of the world’s most illustrious sapphire sources. In this issue, Nathan Renfro, Aaron Palke, and Richard Berg offer a mining history and gemological characterization of Yogo sapphires. The cover photo shows a suite of rough Yogo sapphires atop samples of the ouachatite dike rock in which they are found. The largest rough sapphire weighs 8.49 ct. Photo by Kevin Schumacher; courtesy of Don Baide (The Gem Gallery, Bozeman, Montana).

Thanks to notable diamonds such as the Hope and the Blue Moon of Josephine, there is greater public awareness of blue diamonds than any other fancy color. The lead article of the Summer 2018 Gems & Gemology reviews the characteristics of the more than 15,000 blue, gray, and violet diamonds examined at GIA’s labs over the past decade, while another article investigates the color origin of Fancy Dark brown-black diamonds from Marange, Zimbabwe. Other diamond-related content includes a synthetic diamonds chart and a new column about the value of natural diamonds to our understanding of the Earth. The issue also features a study of Japanese bead-cultured pearls from Lake Kasumigaura, traces the origins of an engraved Early Byzantine almandine garnet, and examines the characteristics of sapphires from Yogo Gulch, Montana.
NATURAL-COLOR BLUE, GRAY, AND VIOLET DIAMONDS: ALLURE OF THE DEEP

A few recently discovered blue diamonds are displayed alongside some legendary gems within the blue/gray/violet color range. Clockwise from upper left: the 30.62 ct Blue Heart diamond, photo by Chip Clark, © Smithsonian Institution; a 0.77 ct Fancy Dark gray-violet shield cut, photo by Robert Weldon/GIA; a 1.23 ct Fancy Dark gray diamond, GIA photo; the 45.52 ct Fancy Deep grayish blue Hope diamond and Fancy Deep blue 31.06 ct Wittelsbach-Graff diamond, photo by Robert Weldon/GIA, courtesy of the Smithsonian Institution.
Almost all fancy-color diamonds in the blue/gray/violet range attribute their hue to four main causes, which include structural defects and the presence of inclusions. The Summer issue’s lead article, by Sally Eaton-Magaña, Christopher M. Breeding, and James E. Shigley, reports on these color-causing mechanisms. The authors delve into the gemological characteristics and spectral properties of the 15,000+ natural, untreated blue/gray/violet diamonds examined at GIA’s labs over the past decade.
BLACK DIAMONDS FROM MARANGE (ZIMBABWE): A RESULT OF NATURAL IRRADIATION AND GRAPHITE INCLUSIONS

DiamondView and visible light images of two diamonds that show radiation stains within fractures in the diamond. Non-luminescent regions in the DiamondView images are associated with extensive radiation damage along fractures in the diamonds. Photos and images by Karen Smit.
Graphite-containing diamonds from the alluvial deposits in Marange, Zimbabwe, may be heat treated to yield gem-quality material, but this may create difficulty in distinguishing these specimens from naturally occurring black diamonds. Karen Smit and her coauthors examine the characteristics of a suite of 40 Fancy Dark brown-black diamonds from Marange in order to document the characteristics that would separate them from treated material. The authors uncover various causes of color in these diamonds.
AN EARLY BYZANTINE ENGRAVED ALMANDINE FROM THE GARIBPET DEPOSIT, TELANGANA STATE, INDIA: EVIDENCE FOR GARNET TRADE ALONG THE ANCIENT MARITIME SILK ROAD

Comparison of inclusions in the Early Byzantine engraved gem (left) with garnets from the Garibpet deposit (right). A and B: Inclusion-rich core and inclusion-poor rim with sillimanite fibers at the boundary. C and D: Irregularly shaped ilmenite. E and F: Subrounded quartz crystals. G and H: Large long-prismatic apatite crystal (a) with characteristic graphite inclusions, along with short-prismatic zircon (z) and monazite (m) crystals. Photomicrographs by H.A. Gilg.
An almandine garnet engraved with a Christian stepped-cross motif popular on Byzantine coinage is the focus of this study by H. Albert Gilg, Karl Schmetzer, and Ulrich Schüssler. Nondestructive analytical methods indicate that the almandine is most likely from India’s Garibpet deposit, giving credence to garnet trade between the eastern coast of India to the Byzantine Empire during the early Middle Ages.
CULTURED PEARLS FROM LAKE KASUMIGAURA: PRODUCTION AND GEMOLOGICAL CHARACTERISTICS

The Chinese freshwater nucleated cultured pearls in this strand from Lake Taihu, also cultured by the Hyriopsis schlegelii × Hyriopsis cumingii hybrid, are 10 mm in diameter and show a color range and luster similar to Kasumiga pearls. Photo by Ahmadjan Abduriyim.
Freshwater pearl culturing began in pre-World War II Japan and reached its peak between 1970 and 1980, only to be overtaken by Chinese production. Current Japanese production at Lake Kasumigaura—Japan’s second-largest lake—is comparatively low, but these cultured pearls have become quite popular in the United States and Europe. Ahmadjan Abduriyim relates the history of Japanese freshwater bead-nucleated pearls, as well as the current state of production and the characteristics of the many-colored specimens.
GEMOLOGICAL CHARACTERIZATION OF SAPPHIRES FROM YOGO GULCH, MONTANA

This suite contains more than 36 carats of Yogo sapphires. Courtesy of RareSource. Photo by Robert Weldon/GIA.
Yogo sapphires are renowned for their clarity and vibrant blue color, and their unique characteristics make them easily recognizable to experienced gemologists. However, mining interests have long found it difficult to maintain long-term activity at this source. In this article, Nathan Renfro, Aaron Palke, and Richard Berg offer a comprehensive look at the history, gemological properties, and trace-element chemistry of the corundum yielded from this important gem deposit in the United States.
SYNTHETIC DIAMONDS CHART

The Summer 2018 G&G contains a foldout wall chart showing the characteristics of synthetic diamonds.
Our newest wall chart, coordinated by Sally Eaton-Magaña and Christopher M. Breeding, presents a visual guide to the growth processes and major gemological spectroscopic features of synthetic diamonds grown by the high-pressure, high-temperature (HPHT) and chemical vapor deposition (CVD) methods. Additional resources for further study are also provided.
LAB NOTES

Diagram showing the proposed model of the beryl and glass assemblage. Final faceting is shown for simplicity. A: The first glass segment (green) is attached to the beryl core (gray). B: Both the core and the first segment are cut to make a flat surface for the second segment. C: The second segment (teal) is attached. D: The segments are again cut. E: The third segment (blue) is attached. F: The assemblage is shown rotated 180° for clarity. All current pieces are cut to create the surface for the final piece. G: The fourth and final segment (purple) is attached. H: Omitted for simplicity, the assembled pavilion would likely be polished flat to make room for the crown. Lastly, the crown (pink) is attached. The diagram was generated using Onshape CAD software.
GIA’s labs report on an emerald imitation created from a beryl and glass assemblage, one natural melee diamond found among a batch of 1,092 HPHT synthetic melee, and a large pinkish orange CVD synthetic diamond.
DIAMONDS FROM THE DEEP

Ringwoodite is the high-pressure form of the mineral olivine (Mg2SiO4) that occurs between 520 and 660 km below the surface of the earth in the transition zone. The first terrestrial observation of this mineral was in a diamond from Juína, Brazil (top left). Water content in this 30 µm inclusion (bottom left) is around 1.4 wt.%, indicating that the global transition zone could contain at least 2.5 times the amount of water as Earth’s oceans. The majority of diamonds come from the cratonic lithosphere (indicated here as yellow diamonds). Superdeep diamonds (indicated here as white and blue diamonds) are rarer and originate from greater depths, often from the transition zone, which extends between 410 and 660 km.
G&G’s newest section highlights the importance of diamond in understanding our planet’s geological formation. This issue’s column focuses on the role diamonds play in understanding the depths at which water is found in the deep earth.
MICRO-WORLD

This copal from Mexico contained a remarkably well-preserved eye-visible mushroom inclusion. Photomicrograph by Nathan Renfro; field of view 9.59 mm.
A mushroom encased in copal, tanzanite with whisker-like merelaniite inclusions, and a star spinel with four and six rays are among the specimens featured in our photomicrography and inclusions section.
GEM NEWS INTERNATIONAL

Left: Three rough garnets (left to right, stones 2, 3, and 4) and one faceted garnet photographed in an LED light source with 6000K color temperature (a daylight-equivalent light simulator). Right: The same stones photographed in an LED light source with 3100K color temperature (an incandescent light simulator). The 2.705 ct faceted stone measures 8.08 × 7.18 × 5.49 mm. Photos by Kevin Schumacher.
Notes from the around the world highlight color-change grossular garnets from Ethiopia, a Mozambican green-blue Maxixe-type beryl, the Gemstones and Sustainable Development Knowledge Hub, and the separation of glass-filled rubies using the DiamondView instrument. @topic:2


Publish Year: 2018 Title: Observation of Etched Surface Micro-Features on HPHT Synthetic Diamonds Using Laser Confocal Microscopy Abstract: Figure 1. Laser confocal microscopy (LCM) shows traces of metallic catalyst and step-like growth marks in an HPHT synthetic diamond’s interior. Photo by Xuxu Wu.

China is the world’s largest HPHT synthetic diamond producer, with an annual output of more than 3,000 tons of rough industrial diamonds. The production technology of HPHT synthetic diamond is quite mature, and most Chinese HPHT synthetic diamonds use the hexahedral static pressure method. The diamond crystals grow out of high-purity graphite through a high-temperature and high-pressure process, and then the superfluous graphite is removed by acid cleaning (Z. Song et al., “Identification characteristics of large near-colourless HPHT synthetic diamond from China,” Journal of Gems and Gemmology, Vol. 18, No. 3, 2016, pp. 1–8).
Acid cleaning of HPHT synthetic diamond is usually done with 90% H2SO4 and 10% HNO3. This process can remove graphite and metal impurities that remain on the diamond surface and in crevices (L. Yin et al., “Micromechanism of the artificial diamond’s growth,” Journal of Synthetic Crystals, Vol. 29, No. 4, 2000, pp. 386–387). During the growth process, the metal catalyst and graphite are in close contact with diamond and continuously participate in crystal growth.
To the best of our knowledge, no research has been done on the surface characteristics of HPHT synthetic diamonds after acid cleaning, which can reveal the growth features of HPHT diamond. In this study, 39 HPHT synthetic diamonds produced in China were observed using laser confocal microscopy (LCM). The laser confocal microscopy measures the surface topography of the sample moving focused laser spots over the sample with a galvanometer scanner. The strongest-intensity scanning points in each vertical scan layer are recorded and used to construct the 3D topography through a pixel-by-pixel method (W.-C. Liu et al., “A self-designed laser scanning differential confocal microscopy with a novel vertical scan algorithm for fast image scanning,” IFAC-PapersOnLine, 2017, Vol. 50, No. 1, 2017, pp. 3221–3226). Therefore, the laser confocal microscope can overcome the problem of depth of field and observe the surface characteristics of materials clearly.
The characteristics of the structure after acid cleaning are observed on the surface of an HPHT synthetic diamond and on the inside of the crystal. An HPHT synthetic diamond was cut into thin slices and then washed by acid, exposing its internal structure (figure 1). Metal catalysts and a small amount of graphite remain in diamond crystals during growth, leaving holes in the interior. Due to the lack of raw material for growth in the hole, a step-like structure was left in the space that was not fully filled with crystallized diamond.

Figure 2. 3D scanning of micro-features by LCM shows the depth change and relative spatial relation. Image by Xuxu Wu.
The fine structure of the step-like growth can be expressed by using the 3D scanning function of the laser confocal microscope. The images built in the three-dimensional coordinate system can show the depth and spatial relationship of the microstructures (figure 2). The irregularly etched structures, the depth of voids left by metal catalysts, range from 5 to 17 μm.

Figure 3. Step-like irregular pits and lines on the surface of the HPHT synthetic diamond.
The inset shows a simulation of the sample’s stacked triangular growth structure. Photo
by Xuxu Wu.

Figure 4. The surface of this HPHT synthetic diamond presents several groups of
parallel lines. Photo by Xuxu Wu.
After acid cleaning, HPHT synthetic diamonds will display step-like irregular pits and lines on the surface (figure 3). The triangular growth structures of HPHT synthetic diamonds are stacked on the surface with slight displacement. Rectilinear line marks on the surface of HPHT synthetic diamonds (figure 4) are also very common, and may be traces of the displacements that develop between small crystals due to compression during the growth process.
Characteristic patterns observed on the surface of HPHT synthetic diamonds are related to metal catalysts and diamond particles, revealing the order of growth of synthetic diamonds. The step-like structure with the same angle is very common. The etched microstructure caused by metal catalysts usually displays irregular patterns. The several groups of parallel straight lines could be caused by the displacement and friction between a large number of tiny diamonds in the growth chamber. LCM is very reliable at revealing surface micro-features on HPHT synthetic diamonds, and it should be more widely applied to gemological research.
Contributors’ note: This study was partially supported by the National Natural Science Foundation of China (grants 41473030 and 41272086). @topic:4


Publish Year: - Title: Spring 2018 G&G: Color Origin of Green Diamonds, Iridescence in Hematite, and the Outlook from Tucson Abstract: Colored by atomic-level defect arrangments, natural-color green diamonds are among the rarest gemstones found on Earth. The cover photo showcases diamonds that display a range of green hues. The diamonds in the rings (clockwise from top) are a 4.17 ct Fancy Vivid yellowish green, a 10.18 ct Fancy Intense yellow-green, and a 3.88 ct Fancy Vivid green, respectively. The unmounted diamonds in the top row are a 1.42 ct Fancy Vivid bluish green, a 1.01 ct Fancy Vivid yellowish green, and a 2.06 ct Fancy Vivid green-blue. In the bottom row are a 0.55 ct Fancy Vivid green and a 0.55 ct Fancy Vivid bluish green. Photo by Robert Weldon/GIA, courtesy of Optimum Diamonds.

Green is among the rarest hues found in colored diamonds, and there have been few published studies. The lead article of the Spring 2018 Gems & Gemology reviews the characteristics of these uncommon gems as observed at GIA’s labs. Other articles explore the causes of iridescence in Brazilian hematite and the application of DNA techniques to identifying Japanese akoya cultured pearls. The issue also includes coverage of the annual Tucson gem shows, the 2018 Challenge, and the results of the Dr. Edward J. Gübelin Most Valuable Article Award.
NATURAL-COLOR GREEN DIAMONDS: A BEAUTIFUL CONUNDRUM

Natural-color green diamonds such as these beautiful gems span a range of colors. From left to right: Fancy Vivid green-blue (2.06 ct), Fancy Vivid yellow-green (1.01 ct), Fancy Dark gray greenish yellow (3.08 ct), and Fancy Intense yellow-green (2.01 ct). Each of the four main color-causing mechanisms usually produces slightly different green hues. Photo by Robert Weldon/GIA, courtesy of Optimum Diamonds.
Diamonds with natural color comprise less than 0.4% of all diamonds submitted to GIA. Of these, stones with a pure green hue are among the rarest. In the last decade, GIA labs have examined more than 50,000 natural-color green diamonds. The lead article, by Christopher M. Breeding, Sally Eaton-Magaña, and James E. Shigley, documents their properties and discusses the radiation exposure and atomic-level defects that cause this hue in diamonds, as well as the difficulties of separating natural-color and treated material.
IRIDESCENCE IN METAMORPHIC “RAINBOW” HEMATITE

Rainbow hematite from the Andrade mine in João Monlevade, Minas Gerais, Brazil. Photo © Rock Currier, Mindat.org.
Rainbow hematite was first uncovered from Minas Gerais, Brazil, and since then it has been used in award-winning jewelry pieces. Xiayang Lin and her coauthors investigate the cause of iridescence in this material through electron microscopy, atomic force microscopy, and synchrotron X-ray diffraction analysis. They assert that the iridescence arises from a periodic microstructure, consisting of spindle-shaped hematite nanocrystals containing minor Al and P impurities, resulting from arrested crystal growth.
DNA TECHNIQUES APPLIED TO THE IDENTIFICATION OF JAPANESE PINCTADA FUCATA PEARLS

Between November and January of each year, pearls are harvested at Uwajima from akoya shells operated on either six months prior (classified by the Japanese as tonen-mono) or 18 months prior (koshi-mono). A: An Uwajima pearl farmer’s work hut. B–F: Various scenes from harvesting in a shed on one of the floating rafts. B: Oysters are removed from a net on the floor to separate the living mollusks from the dead ones. C: After the shells are opened on a table, the adductor muscles are removed and the other soft tissues are separated. D: The liquefied soft tissues containing the bead-cultured pearls are collected in a blue plastic bucket. E: The remaining organic matter containing smaller “keshi” pearls is poured into a separator to remove the keshi pearls. F: The bead-cultured pearls are placed into a wooden box for cleaning and subsequent inspection. Photos by K. Saruwatari.
One of the challenges of modern pearl identification is the separation of saltwater mollusk species that produce white, cream, or silver nacreous pearls. A team led by Kazuko Saruwatari used DNA techniques on akoya pearl-producing mollusks from Uwajima, Ehime Prefecture, Japan, to see if the mollusk species could be pinpointed. The authors were able to amplify the 16S rRNA gene from the mantle tissues of donor and host pearl oysters as well as from tiny amounts of pearl powder, and successfully identified the Pinctada fucata species.
LAB NOTES

A face-up view of the near-colorless 1.21 ct fracture-filled square modified brilliant cut. Photo by Robison McMurtry.
In this issue, reports from GIA’s labs include an HPHT-processed diamond fraudulently represented as untreated, the analysis of five CVD synthetic diamonds greater than three carats, and a natural blister resulting from the entombment of a pearlfish within a P. maxima shell.
MICRO-WORLD

Prominent agate-like banding was seen in the opal. Photomicrograph by Nathan Renfro; field of view 8.22 mm.
Entries in G&G’s section on inclusions and photomicrography spotlight an opal with agate-like banding, a natural diamond with etch channels, and a pink tourmaline crystal within a spodumene host
GEM NEWS INTERNATIONAL

Although traffic at the AGTA show was lighter than in some previous years, demand was brisk and most traders were satisfied with their 2018 business. Photo by Kevin Schumacher.
In addition to our annual Tucson report, GNI features entries on aquamarine from Pakistan’s Shigar Valley, Concho pearls from Texas, and an irradiated and annealed blue type Ia diamond.

The Spring issue also contains the 2018 Gems & Gemology Challenge quiz. Score 75% or better and you’ll receive a certificate of completion (PDF file); earn a perfect score and your name will be listed in the Fall 2018 issue. Mail-in cards and online entries for the Challenge must be submitted by Friday, August 10, 2018. @topic:10


Publish Year: - Title: Retail Group Sees Good Holiday; Fancy Color Diamonds Cap Auction Season Abstract: The 14.93 ct “Pink Promise” Fancy Vivid pink diamond may be the most expensive stone Christie’s has ever sold at its Hong Kong auction house. The diamond is expected to sell for as much as $40 million. Photo courtesy of Christie's Images.

The U.S. National Retail Federation predicts that overall holiday spending will increase 3.6% to 4% over last year, citing a strong economy and rising confidence in employment and wages.

The trade group noted that retailers have been stocking record amounts of merchandise in preparation for a good season.

As reported last month, jewelry sales in the U.S. have been running 5.6% above last year’s levels. Demand for diamonds and gemstones, however, remains concentrated in relatively narrow categories of goods. In addition, according to press reports, consumers seem to be edging from tangibles, such as jewelry, toward travel and other experience-related products. This means competition for their discretionary dollars will be keener than ever.

Retail sales in China continue to recover with most of the major retailers reporting double-digit gains over last year’s totals. Demand for gem-set jewelry declined slightly on the mainland, but grew sharply in Hong Kong and Macau.
AUCTIONS
The sale of a 24.78 ct Fancy Intense pink diamond made news around the world seven years ago for its astounding price: $46.2 million. The diamond, named the Graff Pink by its buyer, brought the highest price ever paid for a gemstone at auction.

A similarly striking diamond (both were graded by GIA) was the centerpiece of Sotheby’s Geneva Magnificent Jewels auction on Nov. 15. It is 12.5 carats larger than the Graff Pink, but carried a pre-sale estimate of $20 to $30 million.

While the final price could go higher, the pre-sale estimate price reflects a key factor in auction prices at those extreme levels: the pool of potential buyers in the market for such a stone is quite small. If one or two major buyers are out of the market for some reason, prices for these stones can fall well short of similar items in previous sales, even as demand and prices for less costly gems remain solid.

It is true that auction prices for major diamonds and colored gems are not setting records at the pace they had several years ago, but in general they have remained solid.

The other major diamonds on the block at the Sotheby’s Nov. 15 sale were a pair of Fancy Intense yellows called the Donnersmarck Diamonds, named for La Paiva the Countess Henckel von Donnersmarck. The countess began a relationship with Prussian industrialist Guido Henckel von Donnersmarck in the early 1850s and married him in 1871. The two GIA-graded diamonds are 102.54 ct and 82.48 ct which, when last sold in 2007, brought in $3.25 million and $4.66 million respectively – with the smaller stone unexpectedly realizing the higher price.

A pink diamond that Christie’s calls “the most expensive jewel ever offered” at its Hong Kong house is expected to bring as much as $40 million on Nov. 17. The 14.93 ct “Pink Promise” diamond is a GIA-graded Fancy Vivid pink oval cut diamond mounted into a ring.

The same sale will also feature an 8.8 ct Fancy Intense pink diamond expected to sell for $8 to $12 million and an 8.17 ct Burmese ruby ring that is estimated to sell at $5.8 to $8 million. @topic:7


Publish Year: - Title: Spring 2017 G&G: Brazil’s Diamond Production, Cuprian Liddicoatite, Silicon in Corundum, and Tucson Coverage Abstract: The lead article of this issue covers Brazilian diamond production, which reached its peak in the late 1700s. Our cover shows a brooch dating back to the mid-19th century. This piece contains a 0.77 ct natural Fancy Light pink antique pear-shaped diamond set in darkly patinated silver ribbons over gold. The total weight of the diamonds exceeds 5.20 carats. Photo by Robert Weldon/GIA, courtesy of Lang Antique & Estate Jewelry.

	From Brazilian diamonds and Japanese jadeite to Indian iridescent quartz and Polish by-product zincite, a world of wide-ranging topics is covered in the Spring 2017 issue of Gems & Gemology. The issue looks at historical and unexpected sources of gemstones, plus surprising discoveries revealed through advanced chemical analyses. News and updates from the annual Tucson gem shows and our multiple-choice Challenge quiz are also included in the Spring issue.

	BRAZILIAN DIAMONDS: A HISTORICAL AND RECENT PERSPECTIVE

	The Portuguese Placa dos Três Militares, or Badge of the Three Military Orders, was
	made in 1789, and is now part of the crown jewelry collection of the Ajuda National
	Palace in Lisbon. The badge consists of Brazilian diamonds as well as emeralds and
	rubies, and it is designed in a way to conceal the metal mounting and emphasize the
	gems. Photo by Manuel Silveira Ramos, courtesy of the Ajuda National Palace.

	Brazil is known for its wealth of colored stones, but it was at one time the world’s leading diamond producer. For three centuries Brazil has supplied a steady, if relatively small, supply of diamonds to the world market. It is also a source of superdeep and fancy-color diamonds and carbonado. In Brazil, diamonds are gathered from alluvial deposits (primarily in Mato Grosso and Minas Gerais), while primary sources remain unknown. Authors Darcy Svisero, James Shigley, and Robert Weldon look at Brazil’s centuries-old diamond production with historical perspective, geological insight, and expectations for future mining.

	COPPER-BEARING LIDDICOATITE TOURMALINE

	Six of the 13 cuprian liddicoatite tourmalines from this study. The faceted stones weigh 1.59–9.63 ct (average 3.95 ct). They are transparent and have greenish blue, green-blue, and green colors. Photos by Masumi Saito.

	Copper-bearing (Paraíba) tourmaline is usually classified as part of the elbaite species. Recently, 13 cuprian tourmalines submitted to GIA’s Tokyo lab were analyzed with LA-ICP-MS for origin determination. While the origin of the stones remains unknown, Yusuke Katsurada and Ziyin Sun discuss the surprising results that led them to classify the samples as liddicoatite, rather than elbaite.

	THE ROLE OF SILICON IN THE COLOR OF GEM CORUNDUM

	Paula Crevoshay’s “Yogo Columbine” pendant displays the remarkably consistent blue color of Yogo sapphires: 243 in all, with a total weight of 13.89 carats. The piece also contains 0.59 ct of yellow sapphires and 1.37 ct of diamonds, set in 18K yellow and white gold. Photo by Orasa Weldon.

	The chemical interactions of silicon, titanium, and magnesium are known to influence the color of gem-quality corundum, but until recently the role of silicon has not been fully understood. John Emmett, Jennifer Stone-Sundberg, Yunbin Guan, and Ziyin Sun explore how ion implant standards and the application of SIMS has led to accurate measurement of silicon in corundum for the first time. This measurement makes clear the important role of silicon in corundum color; the blue of Yogo sapphire from Montana is used to illustrate this discovery.

	JAPANESE JADEITE: HISTORY, CHARACTERISTICS, AND COMPARISON WITH OTHER SOURCES

	A large, attractive jadeite boulder from Itoigawa, Japan, characterized by mixed white
	and green colors. This boulder weighs 40.5 kg and measures approximately 39 cm
	high, 32 cm long, and 26 cm wide. Photo by Ahmadjan Abduriyim.

	Gem-quality jadeite jade has been known from Japan for millennia. In this article, Ahmadjan Abduriyim, Kazuko Saruwatari, and Yusuke Katsurada examine the historical context, chemical composition, and color of Japanese jadeite. They also compare characteristics of samples from the Itoigawa, Omi, and Wakasa regions to jadeite from Burmese, Guatemalan, and Russian deposits.

	CAUSES OF IRIDESCENCE IN NATURAL QUARTZ

	Iridescence is clearly visible on the minor z face of this iris quartz from Jalgaon, India.
	Photomicrograph by Peter J. Heaney; field of view 4.5 mm.

	The phenomenon of iridescence in gemstones is caused by either thin films or repetitive substructures. In an exploration of iris quartz specimens from Jalgaon District, India, Xiayang Lin and Peter Heaney discover a ridge and valley structure, produced by differential etching on the material’s minor z face, which produces its iridescent effect.

	CHARACTERISTICS OF GEM-QUALITY BY-PRODUCT SYNTHETIC ZINCITE

	Most of the by-product synthetic zincites in this study had a reddish orange to yellow color; one sample (ZnO-G) was yellowish green. Top row, left to right: samples ZnO-LC (69.23 ct) and ZnO-SC (31.71 ct). Bottom row, left to right: samples ZnO-G (0.32 ct) and zin-7 (5.61 ct). Composite photo by Ji Zhang.

	Synthetic zincite has been found in industrial kilns in Poland as a by-product of zinc oxide powder production. This accidental zincite has better transparency and brighter color than its natural counterpart. Ji Zhang, Yujie Gao, and Guanghai Shi examine samples of by-product synthetic zincite from a Polish foundry to establish their distinguishing characteristics, identify their inclusions, and find their cause of color.

	LAB NOTES

	This 0.42 ct green HPHT synthetic diamond displayed strong growth sectors that were observed without magnification. Photo by Jian Xin (Jae) Liao.

	GIA’s gemologists report on notable lab submissions, including a surprising source of green color in HPHT synthetic diamond, a Paraíba tourmaline with an unusual submetallic coating, and a cape diamond showing yellow phosphorescence.

	MICRO-WORLD

	In this scene, pyrite inclusions have dissolved, leaving behind hematite and goethite, both of which react dramatically to polarized light. Photomicrograph by John Koivula; field of view 10 mm.

	The inner world of gemstones continues to captivate, and the Spring 2017 section features sapphires showing negative crystals, flame-like structures in precious opal from Ethiopia, and a mysterious inclusion combination in Sri Lankan topaz.

	GEM NEWS INTERNATIONAL

	A 28.21 ct freeform Oregon sunstone from the Dust Devil mine is the centerpiece of this ring. Photo courtesy of Sonja Kreis Unique Jewelry.

	The GNI section contains G&G’s annual coverage of the Tucson gem shows. Highlights include emeralds from a new deposit in Ethiopia and a Burmese gem update following the lifting of U.S. sanctions on Myanmar. Other entries report on the chemical composition of color-change pyrope-spessartine garnet, and a calcite sphere exhibiting strong phosphorescence.

	The Spring issue also contains the 2017 Gems & Gemology Challenge. Score 75% or better and you’ll receive a certificate of completion (PDF file); earn a perfect score and your name will be listed in the Fall 2017 issue. Mail-in cards and online entries for the Challenge must be submitted by Friday, August 11, 2017. @topic:9


Publish Year: - Title: Fall 2016 G&G: CVD Synthetic Diamonds Survey, Reversible Color Change in Blue Zircon Abstract: Nathan Renfro’s article in this issue describes how exposing blue zircon to long-wave UV radiation causes them to turn brown, and how this color modification can be reversed. The 7.95 ct blue zircon ring on the cover is set in 18K white gold and surrounded by 2.43 carats of rubies. It is shown alongside a similar ring with a 5.46 ct tanzanite center stone. Both were designed by Loretta Castoro of Los Angeles for her KissMe collection. Photo by Kevin Schumacher, courtesy of Loretta Castoro.

	CVD-grown diamonds, colored stones, and Indonesian cultured pearls are featured in the latest Gems & Gemology. The Fall 2016 issue reviews the characteristics of several hundred CVD synthetic diamonds; describes how long-wave UV radiation can turn blue zircon brown; and examines the properties of Vietnamese peridot, grandidierite from Madagascar, and Russian alluvial sapphire. The issue also includes a field report from a trip to a cultured pearl farm on the Indonesian island of Lombok.

	OBSERVATIONS ON CVD-GROWN SYNTHETIC DIAMONDS: A REVIEW

	Since 2003, GIA has examined hundreds of gem-quality CVD synthetic diamonds. As growth technology becomes more advanced, the size and quality of these synthetics continue to increase. In the lead article, Sally Eaton-Magaña and James Shigley survey several hundred, CVD samples, interpreting grading factors and analytical data to gain greater insight into indicators of CVD origin.

The lead article of the Fall 2016 issue reviews the characteristics reported from several hundred CVD synthetic diamonds examined by GIA over the past 13 years. These near-colorless and Fancy Vivid purplish pink samples are representative of most of the CVD-grown samples seen at GIA labs. Photo by Robert Weldon/GIA.

	REVERSIBLE COLOR MODIFICATION OF BLUE ZIRCON BY LONG-WAVE ULTRAVIOLET RADIATION

	After learning from gem dealers that blue zircons had turned brown after exposure to long-wave UV radiation, Nathan Renfro undertook a study to see if the blue color could be restored by exposure to incandescent light. Spectroscopic analyses pinpointed the features responsible for the color modification.

	The 11 faceted blue zircons of unknown origin seen on the left all showed a brown face-up color after several minutes of long-wave UV exposure. Photo by C.D. Mengason.

	SAPPHIRES FROM THE SUTARA PLACER IN THE RUSSIAN FAR EAST

	With only one placer deposit of gem-quality sapphire, Russia has long relied on sapphire from other parts of the world. But the Sutara River region of Russia’s Jewish Autonomous District is another potential source of corundum. A team of researchers led by Svetlana Buravleva uncovered sapphire at the deposit and studied the chemical composition and gemological properties of the cabochon-grade material.

	This silver pendant contains a 65.5 ct sapphire cabochon from Sutara, in the Russian
	Far East. Photo by Svetlana Buravleva, courtesy of A. Kurnosov.

	A NEW DEPOSIT OF GEM-QUALITY GRANDIDIERITE IN MADAGASCAR

	A deposit of grandidierite outside Tranomaro, Madagascar, has yielded bluish green to greenish blue crystals that are among the purest known examples of this material. Delphine Bruyère and her coauthors examined samples from the new source, recording its gemological properties, collecting chemical composition data, and discussing the material’s market potential.

This 0.11 ct round brilliant grandidierite from Madagascar has no eye-visible flaws. Photo by Delphine Bruyere.

	PERIDOT FROM THE CENTRAL HIGHLANDS OF VIETNAM

	Recognizing the importance of Vietnamese peridot to the global gem industry, Nguyen Thi Minh Thuyet and colleagues established the geological and P-T formation of the material, concluding that it derives from a spinel lherzolite source. They also compared the gemological characteristics and geochemical data of peridot from the Central Highlands to specimens from other known localities.

The light yellowish green 5.09 ct peridot in this gold ring is from Vietnam’s Bien Ho deposit. Photo by Nguyen Thi Minh Thuyet.

	BEAD-CULTURED AND NON-BEAD-CULTURED PEARLS FROM LOMBOK, INDONESIA

	In this field report, Nicholas Sturman and his coauthors recount their visit to a pearl hatchery in Lombok, Indonesia. There they observed the daily activities of a pearl farm and collected bead-cultured and non-bead-cultured pearls from P. maxima mollusks for further study and future identification purposes.

A group of bead-cultured pearls of various hues recovered from hatchery-bred Pinctada maxima oysters at Lombok, Indonesia. Photo by Julie Poli.

	LAB NOTES

	Highlights from the Fall Lab Notes section include reports on the capabilities of GIA’s melee sorting service, a sapphire rough filled with green lead glass, a treated pink diamond colored by red luminescence, and a purple fluorite inclusion in emerald.

	MICRO-WORLD

G&G’s photomicrography section includes entries on unusual growth zoning in Pakistani aquamarine, etch features in spinel from Madagascar, and a mobile fluorite inclusion within quartz.

	GEM NEWS INTERNATIONAL

	The Fall 2016 GNI section provides updates on Tanzanian colored gemstone deposits, “Punsiri”-type spectral features in natural yellow sapphire, and use of the DiamondView instrument to identify impregnated jadeite. @topic:4


Publish Year: - Title: Fluid CH4 and H2 Trapped Around Metallic Inclusions in HPHT Synthetic Diamond Abstract: This article was published in Diamond and Related Materials, Volume 68, 2016, Pages 10–12.

	Abstract
Diamonds grown by the high-pressure, high-temperature (HPHT) method commonly contain solid inclusions from the metallic solvent-catalyst they are grown in. Such inclusions give rise to their familiar magnetism. Upon recent analysis of 4 commercial HPHT synthetic diamonds from different sources, several of these solid inclusions were found to have a thin, fluid film or jacket of methane (CH4) and hydrogen (H2) trapped at the interface between the solid inclusion and surrounding diamond. Raman spectroscopy reveals peaks near 2918 cm− 1 and 4156 cm− 1 that correspond to the main vibrations of CH4 and H2, respectively. In some cases the peak position is shifted down by a few wavenumbers due to elevated pressure within the inclusions.

The CH4 and H2 probably formed as the inclusion cooled, when dissolved hydrogen atoms were no longer soluble in the solidifying inclusion phases and were forced to exsolve as H2, as well as CH4 by combining with available carbon. Inclusions can provide an indirect means of studying the effective growth environment. These findings show that hydrogen is commonly present at the site of diamond growth in HPHT synthesis, even if it is not intentionally added among the starting materials. Hydrogen is known to influence diamond growth, based on doping experiments, suggesting that there could be unrealized benefits to gaining better control over hydrogen during routine HPHT diamond synthesis.

Purchase the full article. @topic:4


Publish Year: - Title: Summer 2016 G&G: Diamonds from Diavik, Responsible Sourcing, and Fabergé Cossack Figures Abstract: The lead article in this issue examines the discovery and geology of the Diavik diamond mine, as well as the nature
of the operations at this remote site in Canada’s Northwest Territories, just 220 km south of the Arctic Circle.
The aerial photo on the cover, taken in the summer of 2014, captures Diavik’s isolation and the extent of its operations.
Photo by Dave Brosha, courtesy of Diavik Diamond Mine.

	Diamonds and colored stones, carving and mining, historical treasures and the future of the industry are all featured in the latest Gems & Gemology. The Summer 2016 issue leads with the Diavik diamond mine in Canada’s Northwest Territories. Other articles examine Fabergé figures depicting Russian imperial bodyguards, efforts to bring a sustainable and ethical supply chain to the colored stone industry, the carving of a large opal rough into a museum-quality piece, and the bygone adventures of mine engineer Peter Rainier at the Colombian emerald mecca of Chivor.

	MINING DIAMONDS IN THE CANADIAN ARCTIC: THE DIAVIK MINE

The 187.7 ct “Diavik Foxfire,” discovered in spring 2015, is the largest gem-quality rough diamond found to date at the mine. Photo courtesy of Rio Tinto Diamonds.

	Canada’s remote Diavik mine is one of the world’s preeminent sources of gem diamonds, producing over 100 million carats since 2003. In the lead article, Dr. James Shigley and his team review the discovery, development, and operation of the mine, which is expected to produce through 2024, when the land will be restored through reclamation and remediation efforts. The article is accompanied by exclusive videos captured at Diavik.

	FABERGÉ COSSACK FIGURES CREATED FROM RUSSIAN GEMSTONES

	The Fabergé hardstone figure of Chamber Cossacks A.A. Kudinov, who guarded
	Empress Maria Feodorovna from 1878 to 1915. Photo courtesy of Pavlovsk State Museum
	and Gafifullin (2014).

	Between 1908 and 1916, the Fabergé workshops created approximately 50 hardstone figures representing the Russian people, using Russian gems and precious metals. Timothy Adams and Christel Ludewig McCanless examine two hardstone figures, commissioned by Nicholas II, of Cossack bodyguards who served the Romanov empresses.

	THE COLOR OF RESPONSIBILITY: ETHICAL ISSUES AND SOLUTIONS IN COLORED GEMSTONES

	The mining and processing of colored stones, a multibillion-dollar industry, still lacks an ethical and sustainable mine-to-market supply chain. Jennifer-Lynn Archuleta reports on the inherent challenges and the ongoing efforts  to bring traceability, transparency, and sustainability to the world of colored stones.

	THE CHALLENGES OF CUTTING A LARGE GEM OPAL ROUGH

A side view of the Australian opal rough shows all the color bars and intervening layers of colorless potch. Photo by Robert Weldon/GIA.

	Theodore Grussing explains how he planned and cut a 3,019 ct piece of Australian white opal rough into the Molly Stone, a 1,040 ct museum quality piece with play-of-color across the entire surface. This article describes the many considerations involved in creating this one-of-a-kind gem. Video showing the creation of the Molly Stone enhances the reader’s understanding of the cutting process.

	IN RAINIER’S FOOTSTEPS: JOURNEY TO THE CHIVOR EMERALD MINE

 Colombia’s Sinaí Valley, the sandstone monolith of El Pulpito hangs from a steep cliff in the top right. The Chivor mine is just out of view above the rock. Photo by Robert Weldon/GIA.

	Robert Weldon and coauthors take readers on a trek through Colombian history as they journey to the world-famous Chivor mine, guided by the memoirs of Peter W. Rainier. The field report is accompanied by historical photos from the mine and video of the authors’ journey.

	LAB NOTES

	The Lab Notes section reports on a unique drilled emerald, a natural spinel with an unusual yellowish green color, and the largest blue HPHT synthetic diamonds to date.

	MICRO-WORLD

G&G’s photomicrography section features a metal sulfide inclusion in a pink pyrope garnet, a topaz hosting a triplite inclusion, and a stunning aurora effect in an iris agate (with accompanying video).

	GEM NEWS INTERNATIONAL

Submitted as synthetic diamonds, the 0.99 ct blue-green emerald step cut (left), 0.85 ct brown-yellow standard round brilliant (center), and 1.90 ct deep green standard round brilliant (right) were all identified as synthetic moissanite. Photo by Yanjun Song.

	Highlights from the GNI section include Chinese amber treated through steam dyeing, the spectral characteristics of P. mazatlanica and P. margaritifera oyster species, synthetic moissanite imitating synthetic colored diamond, and more entries from the Tucson gem shows.

	2016 G&G CHALLENGE

	For those interested in testing their knowledge of our 2015 content, the 2016 G&G Challenge will be open until Friday, August 12. Participants who score 75% or higher will receive a certificate of completion, while respondents who earn a perfect score will be listed in the Fall 2016 issue of Gems & Gemology. @topic:2


Publish Year: 2006 Title: The Impact of Internal Whitish And Reflective Graining on the Clarity Grading of D-To-Z Color Diamonds at the GIA Laboratory Abstract: Unlike many other characteristics that affect the clarity grade of a diamond, determination of the impact of “whitish” graining and “reflective” graining requires analysis that goes beyond visibility at 10× magnification. The importance of this determination is further underscored by the fact that such graining often is the only characteristic present in large, high-clarity, high-color diamonds. This article reviews the history of reporting on such graining by the GIA Laboratory, considers the causes of the different types of graining most commonly encountered, and examines the methodology and critical assessment GIA graders use to determine the impact of such graining on the clarity grade of a diamond. @topic:10


Publish Year: 2013 Title: A New Defect Center in Type Ib Diamond Inducing One Phonon Infrared Absorption: The Y Center Abstract: This paper describes the discovery of a new defect center in natural and synthetic type Ib diamonds: the Y center. Sixty-eight natural and synthetic diamonds with detectable C centers, ranging from 0.01 to 1.34 ct and representing common colors for type Ib diamonds (various hues of yellow, orange, brown, and “olive”) were studied.

The other color centers traditionally responsible for one-phonon absorption (i.e., spectral absorption due to the presence of certain defects in the diamond’s lattice structure) include single isolated boron, the A center (di-nitrogen), the B center (four nitrogen atoms surrounding an atomic vacancy in the diamond lattice), the C center (single-substitutional nitrogen, N0), the X center (positively charged single-substitutional nitrogen, N+), and the D, E, and F centers, which have not been attributed to any specific defect.

After correction and normalization of the samples’ infrared spectra, and an attempt to determine the A, B, and C center nitrogen content using spectral fitting data, the researchers found that the margin of error for the C center content was at least 50%. This suggests that some absorption bands underlie the well-known single-substitutional nitrogen absorption at 1130 cm–1. For this reason, all spectra are decomposed again by progressive subtraction of the A, B, C, and X center absorptions. For 38 diamonds, this resulted in a consistent residual absorption with a relatively broad apparent maximum centered at ~1145 cm–1.

A large sample of type Ib diamonds confirmed that this new absorption system is not an artifact of the original spectral decomposition work. The authors propose to call it the Y center because it is clearly related to the single-substitutional nitrogen system of the last named one-phonon infrared absorption center, the X center.

Abstracted by Edward R. Blomgren @topic:4


Publish Year: 2013 Title: Aviat Diamonds: A Window into the Deep Lithospheric Mantle Beneath the Northern Churchill Province, Melville Peninsula, Canada Abstract: The Aviat kimberlites are located in Melville Peninsula in northeastern Nunavut. They are part of the Rae craton, which is composed of Archean granitoid rocks, supracrustal belts, and Paleoproterozoic metasedimentray rocks. The carbon isotopic composition, nitrogen concentration, and nitrogen aggregation state of 70 samples from these kimberlites were analyzed to help understand the composition of diamond-forming fluids, paragenesis of diamond source, mantle residence history, and thermal history of the subcratonic lithospheric mantle. The colors of samples were colorless, gray, brown, and green.

FTIR analysis revealed that the majority were type IaAB, including IaA and IaB. Total nitrogen content ranged from 13 to 1467 ppma. The Aviat diamonds were relatively rich in hydrogen. Absorption bands at 3107, 2786, and 1404 cm–1, caused by bending and stretching of the vinylidene group (C=CH2), were observed in most samples. An additional hydrogen-related band at 3237 cm–1 was also detected.

SIMS analysis revealed nitrogen content ranging from 1 to 1724 ppma. The δ13C isotopic analysis suggested that these diamonds were precipitated mainly from carbonate-bearing fluids. Large variations in nitrogen content and δ13C values, though they were not correlated, were observed in growth sectors, suggesting multiple events of fluid derivation from different sources, mainly ecologitic and also probably peridotitic. But the relationship between CL and carbon isotopic composition suggested that non-luminescent diamond may have been formed during one episode of growth. The Aviat diamonds were possibly formed from diamond-forming fluids or melts from several orogenic events, such as transportation of graphitized organic matter and marine carbonates into the deep mantle via subducting oceanic slabs.

Catastrophic platelet degradation was suggested by the positive correlation between platelets and B aggregates of nitrogen. This phenomenon was probably caused by transient heating events or deformation or both during mantle residence. Blue luminescence of nitrogen-rich samples may be related to intense degradation of platelets. The residence temperature of most samples was extrapolated to ~1050–1150°C, suggestive of a diamond source near the top of diamond stability field at ~150–170 km.

Abstracted by Kyaw Soe Moe @topic:8