# Publication Year: -
# Title: What Country Do My Diamonds and Other Gemstones Come From?
# Abstract: Dr. James Shigley, GIA Distinguished Research Fellow, giving a lecture for students and the public on “Gemstone Country of Origin Reporting” March 2020 at GIA in Carlsbad. Photo by Emily Lane/GIA

“Since 1931 (GIA’s founding), we have shared everything we have learned with you.”

This quote from Richard T. Liddicoat, GIA’s legendary second president, is how Dr. James Shigley began his recent lecture, “Gemstone Country of Origin Reporting.”

“It is the best short description of why GIA is here,” said Shigley, who is GIA’s distinguished research fellow and holds a Ph.D. in geology from Stanford University. Shigley proceeded to share everything (or many of the things) he’s learned about gemstone origin in his 37 years working in GIA’s research department. He focused most of his presentation on colored stone origin identification, which is detailed in a special Winter 2019 issue of Gems & Gemology (G&G) on country of origin.

“Country of origin reporting [for colored stones] is probably the most difficult challenge we have in the lab for identifications purposes,” Shigley said.

GIA researchers are uniquely able to offer insight into colored gem origin, he explained, because of the sheer volume of stones they see in the lab and in the field. In the past decade, GIA field researchers have gone on 95 field expeditions to 21 countries and collected more than 22,000 samples totaling more than 1 million carats. GIA also has 60 researchers on staff, including more than 20 with doctoral degrees in fields such as geology, chemistry and material science.

The knowledge gained from these field expeditions is part of the “foundation” of the information GIA can provide to the gem trade in its colored stone report service, Shigley said. The GIA Colored Stone Identification and Origin Report has been around for decades, but the GIA Diamond Origin Report is relatively new.

A ruby crystal in calcite, left, and a round cut ruby, both from Myanmar (formerly known as Burma). Specimen courtesy of the Dr. Eduard J. Gübelin collection. Photo by Robert Weldon/GIA
How Does GIA Determine Where Colored Gems are From?
“It’s important to recognize that a country of origin report is an expert opinion. We [often] weren’t there when it [the gemstone] was found,” Shigley said. “It is an expert opinion based on examination of the sample that is presented to us.”

The assumption is that stones from different places should have different gemological properties he said, but it “doesn’t always pan out that way.”

Shigley reviewed some of the challenges of country of origin reporting for colored gemstones:

The geology of the gem deposit is often not well known and many are alluvial occurrences have an uncertain source (“We don’t know where the original host rock is located,” he said. “it could be miles and miles away.”)

Access to the deposit may be difficult.

Gem deposits do not stop at country borders.

Deposits in different countries can produce very similar material (such as sapphires from Madagascar, Kashmir and Sri Lanka).

Different deposits can be found in the same country.

“What these challenges show,” Shigley said, “is that the geology determines the gemological properties — the inclusions, the chemistry and all of the other properties of the gem material.”

Country or geographic origin reporting began in the 1950s when the famous Swiss gemologist Eduard Gübelin started to provide letters about where the stones his company was selling came from, Shigley said. Gübelin also wrote a series of articles for G&G on how inclusions can help you determine where colored stones come from.

A 7.04 ct oval sapphire from Madagascar. Sapphire is courtesy of Mayer & Watt, Maysville, Kentucky. Photo by Robert Weldon/GIA
Building on what researchers have learned and documented in the past, GIA created a field gemology program a decade ago to “go to where the gems are,” Shigley said. They are collecting samples to build a reliable database, videotaping and photographing the area and interviewing miners to get a complete picture of what’s going on in that particular time and place. He said this program is the foundation of GIA’s Colored Stone Country of Origin Reports, and it provides valuable information for GIA education courses.
While colored gemstones continue to be found in Australia, Brazil and Columbia, in many cases today they are found in two regions of the world. The first is the arch of countries between the Indian subcontinent and Asia (Iran, Pakistan, Afghanistan, northern India, Myanmar, Cambodia Vietnam and Thailand) that represent the collision zone between India and Asia — this collision zone produced the metamorphic and magmatic conditions necessary to form gem deposits. The second region represented is Eastern Africa (Ethiopia, Somalia, Kenya, Tanzania, Madagascar, Mozambique), as well as Sri Lanka and southern India — another continental collision zone with the right geologic conditions that produce gem deposits.

Two Madagascan miners look through river gravel for sapphires. This photo was taken on a GIA Field Expedition to Madagascar in September 2010. Photo by Vincent Pardieu/GIA
GIA field gemologists travel to these countries to collect gem specimens for research. These specimens are classified according to how closely they are collected to the source:

Type A ‒ collected onsite by a GIA gemologist

Type B ‒ the gemologist witnesses the samples being mined

Type C ‒ samples are purchased from a miner at the mining site

Type D ‒ samples are purchased from a miner but not onsite

Type E ‒ samples are purchased from a secondary source (not the miner) close to the mine

Type F ‒ samples are purchased from a secondary source on the international market

Most of the samples GIA collects are Type D or E, supported by types A, B and C when available. These samples are taken back to the lab so researchers can study their color, fluorescence, inclusions, growth zoning, chemical composition, spectra (visible and infrared), Raman spectroscopy and photoluminescence. These stones are also photographed, often at 100x magnification, so their inclusions and other visual features are recorded. The data collected lets scientists determine the cause of color in the gem material at hand, which helps to determine origin or to classify gemstones into different types.

This emerald crystal buried in its host rock was found in Colombia, the world’s largest producer of emeralds. Photo by Orasa Weldon/GIA
The instruments needed to collect all of this data, such as the scanning electron microscope and the laser-ablation mass spectrometer, cost anywhere from $100K to $1 million each. Some of these instruments are able to detect very tiny quantities of trace elements in the parts per billion (PPB), and can pick up elements that are unique to certain countries of the world. The greatest challenge in collecting data on gemstones is using non-destructive ways to analyze gemstones.
Another challenge to gemstone origin determination is that countries are continually being added to the list as gemstones are discovered at new locales, so GIA field researchers are always on the march to document more gemstones. Shigley used ruby as an example of how the discovery of new deposits have increased over the years: in 1950 there were eight known ruby sources in the world, today there are 30.
“They don’t necessarily produce the best quality of material, but material from all of these deposits are in the market and may show up here for an origin report,” he said. “The challenge is the growing number of localities with very different geology — and sometimes with very similar geology.”
“The database is accessible in GIA’s identification laboratories for comparison with client stones for country of origin services. Each expedition expands the database and improves the reliability of the reference collection and GIA’s laboratory services.”
Can GIA Figure Out Where a Diamond is From?
Shigley also discussed how determining colored stone country of origin differs from determining country of origin for diamonds, which is nearly impossible, because once a diamond is cut, there are no distinctive features to determine where it came from.

“We cannot tell where a diamond comes from based on the diamond itself,” Shigley said.

Certain mines, however, are associated with a certain size or quality of diamond, e.g. the Cullinan Mine in South Africa, which is renowned for having produced several legendary large, high-clarity diamonds, including the Cullinan, the largest diamond rough ever found. The Argyle Mine in Australia has been the world’s primary producer of pink diamonds for decades.

The 302.37-carat Graff Lesedi La Rona diamond was found in Botswana. The provenance of large, high-quality, record-breaking diamonds tends to be easier to track. Diamond courtesy of Graff and photo by Donald Woodrow

Shigley outlined the main reasons why it is impossible to determine the geographic origins of diamond based on gemological and scientific examination.

Where they form: Diamonds form deep in the Earth, where conditions are more homogenous. Also, there aren’t any distinctive mineral inclusions associated with any particular location.

Diamond structure, chemistry and analytical challenges: Diamonds are made up of carbon and sometimes a small amount of nitrogen and boron, which are next to each other in the periodic table, Shigley said, so the atoms are about the same size and can easily substitute for one another in the diamond structure.

“Diamond is a very close-packed tetrahedral arrangements of carbon atoms that are held together by very strong short, covalent bonds,” he said. “It is hard to get other trace elements into the diamond structure in very much quantity. [If they are there] they are very trace amounts in the parts per billion level.”

Additionally, analysis of trace elements in diamonds requires sophisticated analytical equipment and a method that may destroy part of the diamond sample. Spot analysis can be done using Secondary Ion Mass Spectrometry (SIMS), but this is “probably a million-dollar piece of equipment” usually only found at universities — GIA does not have one, Shigley said

A piece of diamond-bearing kimberlite from South Africa. Photo by Robert Weldon/GIA
Weathering: Some diamond deposits are secondary, where the diamond is recovered from a river or sediment by panning. Diamonds are brought to the Earth’s surface by an explosive eruption that forms a volcanic pipe filled with diamond-bearing igneous rock known as kimberlite. Kimberlite weathers quickly, releasing the diamonds and they go downhill, either by gravity or water, and are then carried by river systems downstream — possibly hundreds of miles away — or incorporated into sedimentary rock.

“The river takes them many miles away from their original pipe location, so we don’t even know where the pipe was,” Shigley said. “And of course, the river crosses many countries. In South Africa, it [the Orange river] transports them all the way to the Atlantic Ocean.”

Lack of a distinctive surface appearance on rough diamonds: Experienced diamond sorters at DeBeers might be able to tell which company mine a rough diamond came from based on its surface features, but this isn’t an exact art and the stones are unrecognizable once surface characteristics are removed in the gem cutting process.

Shigley said the real problem of diamond origin is: Where are you going to get diamonds to study to develop your criteria for country of origin identification?

“You would need a representative sample of diamonds from all of the mines in the world and all of the secondary deposits in the world. And what’s a representative sample — is it 3 or 300 diamonds [from each location]?” he said. Additionally, once you have representative samples, they would have to undergo destructive testing.

“There is no database of rough diamonds available to anyone to tell where they are from and I don’t know of any way, scientifically, to tell where a polished diamond comes from,” he said.  “The database of samples, if it existed, would provide a source of information to try and develop ideas for country of origin determination for diamonds,” he said, adding that the lack of diamonds from secondary alluvial deposits “is a particular problem because of the lack of organized mining efforts and the random finding of diamonds.”

The Diamond Origin Report offers a 4Cs quality analysis as well as confirmation of origin to the gem trade. Pictures of the original rough can be viewed online or on the 4Cs app.
It’s in the leap from rough to polish that GIA breaches the gap. GIA works with diamond mining companies in major diamond-producing countries such as South Africa, Russia, Canada, Namibia, Lesotho and Australia to offer the GIA Diamond Origin Report Program to the gem trade.

“It’s more of a matching service,” Shigley said. GIA takes a rough diamond that comes in a sealed parcel from a client or program participant with its required origin documentation. GIA characterizes it so it is able to later match it to a cut stone submitted for the origin service. The country of origin information confirmed on the report comes directly from the mine.

‘We are saying [on the report] that this is where it is from and we can definitively match it with the original rough diamond,” Shigley said.

GIA matches the gems to their original rough according to their size and color, measurements, gemological observations, absorption and luminescence spectroscopy, fluorescence imaging and information in the GIA database. Each GIA Diamond Origin Report also contains a 4Cs quality analysis in addition to a statement of origin.

GIA has issued nearly 20,000 diamond origin reports. @chapter:21 @chapter:0 @chapter:21


# Publication Year: 2018
# Title: GIA’s 2018 Symposium: Up and Away!
# Abstract: Since GIA’s first International Gemological Symposium in 1982, this event has served as a platform for advancing knowledge in the research and business sides of gemology. For three days, October 7–9, we celebrated the centennial of the incomparable Richard T. Liddicoat by hosting GIA’s sixth Symposium. Nearly 800 attendees from 36 countries gathered in Carlsbad, California, including more than 100 presenters and panelists.
We’ve prepared this special Symposium Proceedings volume of G&G to capture the insights and the spirit of this unforgettable event. Scenes from all three days and nights are shown in the photo montage scenes from all three days and nights are shown in the photo montage.
The Symposium experience began with a powerful opening session featuring The Music Paradigm. Audience members found themselves seated within a live symphony orchestra as maestro Roger Nierenberg offered dynamic lessons on leadership and teamwork. This performance was followed by an opening gala at GIA World Headquarters. On display at the campus were some extraordinary new exhibits assembled by the GIA Museum. This gala was the first of three evening social events for rekindling old friendships and creating new ones.
In the Symposium research track, 37 speaker presentations and 68 poster sessions covered seven important themes: colored stones and pearls, diamond geology, diamond identification, gem characterization, gem localities and formation, general gemology and jewelry, and new technologies and techniques. In the speaker abstracts and the poster abstracts, you’ll find a wealth of informative research summarized. An index of all the presenters appears in the back of the issue.
In a parallel program, classes taught by three professors from the Harvard Business School explored real-life case studies on authentic leadership, customer centricity, and disruptive innovation. Participants gained a deep understanding of these strategic concepts through classroom sessions and discussion groups.
The Symposium’s closing session, the Futurescape Forum, brought together six of the industry’s most influential leaders to forecast what lies ahead as technological breakthroughs, changing consumer tastes, and sustainability concerns continue to reshape the gem and jewelry landscape. You’ll want to read the recap of this lively and thought-provoking panel discussion.
This event would not have been possible without the thousands of hours of planning by the Symposium steering committee and the dedicated efforts of dozens of GIA volunteers, all of whom are recognized on the front and back inside covers of this issue. I am especially grateful to Kathryn Kimmel, GIA’s senior vice president and chief marketing officer, for once again chairing the Symposium and bringing to it her own signature style.
To all those who came to Carlsbad to attend the Symposium, we simply cannot thank you enough for being part of this event. We hope that you came away from it informed and inspired to embrace the future of our great industry. @chapter:42 @chapter:3 @chapter:42


# Publication Year: 2008
# Title: Fall 2008 G&G Book Reviews
# Abstract: “American Mineral Treasures”
By Gloria A. Staebler and Wendell E. Wilson, Eds., 354 pp., illus., publ. by Lithographie LLC [www.lithographie.org], East Hampton, CT, 2008. US$85.00

“The Diamond Handbook: A Practical Guide to Diamond Evaluation, 2nd Ed.”
By Renée Newman, 186 pp., illus., publ. by International Jewelry Publications [www.reneenewman.com], Los Angeles, 2007. US$19.95

“Gems of the World”
By Cally Oldershaw, 256 pp., illus., publ. by Firefly Books [www.fireflybooks.com], Buffalo, NY, 2008. $35.00

“Gems & Minerals”
By Andreas Landmann, 176 pp., illus., publ. by Schiffer Press, Atglen, PA, 2008. $29.99

“Southwestern Indian Jewelry: Crafting New Traditions”
By Dexter Cirillo, photography by Addison Doty, 240 pp., illus., publ. by Rizzoli International Publishers [www.rizzoliusa.com], New York, 2008. US$55.00

“Fleischer’s Glossary of Mineral Species 2008”
By Malcolm E. Back and Joseph A. Mandarino, 345 pp., publ. by The Mineralogical Record [www.minrec.org], Tucson, AZ, 2008, US$26.00

“Gemstones: Enchanting Gifts of Nature”
By R. V. Karanth, 48 pp., illus., publ. by the Geological Society of India [www.geosocindia.org], Bangalore, 2008, US$20.00

“Amazonite: Mineralogy, Crystal Chemistry, Typomorphic Features”
By M. N. Oustooumov, A. N. Platonov, and V. A. Popov, 253 pp., illus., publ. by Nedra, Moscow, 2008, Ru578 [in Russian]

“Infrared Reflection Spectrometry in Advanced Mineralogy, Gemology and Archaeometry”
By Mikhail Oustooumov, 89 pp., illus., publ. by the National University of Mexico Institute of Geophysics [www.igeofcu.unam.mx], Mexico City, 2007 [in Spanish]

“Traditional Jewelry of India”
By Oppi Untracht, 431 pp., illus., publ. by Thames & Hudson [thamesandhudsonusa.com], New York, 2008, US$49.95

To view the full section, download the PDF above. @chapter:23 @chapter:0 @chapter:23


# Publication Year: 2023
# Title: Two Foraminifera-Like Objects Found in a Natural Saltwater Pearl
# Abstract: Figure 1. The 1.57 ct brown nacreous pearl measuring 11.06 × 9.15 × 7.20 mm. Photo by Tony Leung.
GIA’s Hong Kong laboratory recently received a brown nacreous pearl weighing 1.57 ct and measuring 11.06 × 9.15 × 7.20 mm (figure 1). It had a baroque shape and exhibited a soft luster with an unaltered surface. Despite its size, the pearl felt relatively lightweight, indicating the possibility of a hollow or partially hollow internal structure. Viewed under 40× magnification, the surface displayed overlapping nacre platelets in a spiral pattern, similar to that observed in pearls produced by Pteria species mollusks (L. Kiefert et al., “Cultured pearls from the Gulf of California, Mexico,” Spring 2004 G&G, pp. 26–39).
The sample exhibited the typical brownish surface tint of pearls produced by the Pteria mollusk species. Its ultraviolet/visible spectrum showed the characteristic reflectance features of naturally colored pearls formed in this mollusk, with identifiable absorptions at 405 and 495 nm (S. Karampelas et al., “Spectral differentiation of natural-color saltwater cultured pearls from Pinctada margaritifera and Pteria sterna,” Summer 2011 G&G, p. 117). Under long-wave UV radiation, the pearl also displayed moderate red fluorescence, a reaction linked to a type of porphyrin pigment found in pearls originating from the Pteria species (Kiefert et al., 2004). Energy-dispersive X-ray fluorescence analysis showed no traces of manganese and 1150 ppm of strontium, confirming its saltwater origin.

Figure 2. Real-time microradiographs showing the overall internal structure of the pearl (left) and greater detail of the foreign materials (right).
Real-time microradiography revealed a fascinating internal structure (figure 2). A large central void, composed of light and dark gray areas associated with the presence of organic matter, occupied almost the entire interior of the pearl, which explained the lighter than expected heft. Surrounding the void, a few distinct growth arcs were observed, following the outline of the pearl’s shape—a typical feature seen in natural pearls. In addition, two intriguing foreign materials were trapped within the inner wall of the light gray organic-rich area of the void.

Figure 3. μ-CT images revealed more details of the foraminifera-like spheres. Both consisted of a radiating structure that extended from an empty core.
Further analysis via X-ray computed microtomography (μ-CT) imaging revealed the porous nature of these two materials. Resembling foraminifera, a marine micro-skeleton member of a phylum of amoeboid protists, they consisted of radial structures extending from the center of empty cores (figure 3). The pair of near-spherical objects measured 1.50 × 1.25 mm and 1.53 × 1.33 mm, respectively, and appeared to be separate entities while sharing a homogeneous formation. The pearl’s structure was judged to be natural due to the appearance of the natural-looking void, which consisted of a flowy outline, and the presence of the foraminifera-like entities. It is worth noting that most cultured pearls from the Pteria species available in the market are bead cultured pearls. Non-bead cultured “keshi” Pteria pearls are normally of smaller sizes and distinguishable internal structures.
GIA has received numerous pearl submissions in the past with interesting internal structures related to foreign materials. In fact, the skeletal composition of the foreign material observed looked exceedingly similar to that found in a natural pearl examined by GIA’s Bangkok laboratory in 2015 (Winter 2015 Lab Notes, pp. 434–435). However, this pearl stands out for the presence of paired foraminifera-like spheres. No two pearls are the same, and it is always rewarding when advanced testing reveals such captivating features. @chapter:11 @chapter:4 @chapter:11


# Publication Year: 2023
# Title: 2023 Market Report on Jewelry and Gemstone Products in Germany.
# Abstract: Market Overview

As the COVID-19 situation in Germany begins to improve, the jewelry and watch industry is experiencing a resurgence since 2564. It's noteworthy that the Fine Jewelry segment has seen higher sales compared to Costume Jewelry. Besides adornment, mineral-based jewelry like gold, platinum, and silver remains desirable as Germans believe that during uncertain times, minerals retain market value better than other types of jewelry and may appreciate in the long run.

According to Euromonitor International, the jewelry and watch industry has been impacted by the COVID crisis and is slowly recovering. Before the crisis, consumer consumption of jewelry had already decreased. However, higher unit prices due to product uniqueness can contribute to market growth. Analysts view post-COVID growth as temporary, predicting a return to stability in 2566 with a potential continuous decline in consumption rates. External factors like energy issues and inflation may lead to price increases and reduced consumer purchasing power, extending the industry's recovery over several years.

Consumer Behavior

Increasing Digitalization in the Jewelry Industry
The jewelry and gem industry is becoming more digitalized. Retail stores have been crucial for this industry for a long time. However, many stores closed during the recent COVID crisis, providing an opportunity for retailers with online channels to play a more significant role and grow. Currently, popular online fashion platforms in Germany include Amazon, Zalando, and aboutyou, along with specialized online jewelry stores like Kraemer Valmano and Schmuckladen. Some companies have incorporated AR technology for customers to try jewelry digitally and use programs to help them find diamonds or pearls that suit their needs and budget. However, online channels are not yet widely popular for selling high-end or high-value jewelry.

Consumer Focus on Sustainability
Consumers increasingly prioritize sustainability when buying jewelry. They are more aware of fair trade certification, avoiding products with questionable origins like those involving legal issues or labor rights violations. Newer consumers also show interest in lab-grown diamonds or recycled materials in jewelry production due to their lower cost and sustainability. Brands like Korkallee and Holzkern, using materials like recycled wood, are gaining popularity among small-scale customers.

Special Occasion Jewelry
Experts from the jewelry and gem exhibition industry in Germany predict a comeback of wedding ceremonies, with over 100,000 weddings postponed due to the COVID-19 pandemic. In 2564, only 357,800 weddings were held, the lowest in history according to German statistics. However, more couples are now planning engagements, creating opportunities in 2566 for selling engagement rings. European consumers often buy wedding or couple rings valued between 1,000 to 4,000 euros, preferring classic styles made from precious metals like gold, white gold, and platinum.
Trends in Jewelry and Products

1) Trends in Jewelry Fashion for the Year 2023
Breuninger's jewelry design trends for the year 2023 include:
- Simple and classic jewelry designs but with a focus on using high-quality materials.
- Jewelry pieces featuring thick and bold chain links, such as bracelets, rings, and necklaces made of gold or silver.
- Jewelry designs with clean and simple graphic lines, creating a sleek and modern look.
- Minimalist style jewelry with contemporary shapes, layered for a varied look, including rings, necklaces, and bracelets.

2) Popular Jewelry Materials for the Year 2023
Popular jewelry materials for the year 2023 include:
- Gold remains popular for its luxurious and classic appeal, whether in white gold, rose gold, or yellow gold.
- Silver, a valuable metal, is popular for making rings, necklaces, bracelets, and earrings, both in classic and trendy styles, enhancing the wearer's modern and versatile image.
- Pearls have regained popularity for their beauty and natural luster, with various shapes like teardrops or unique baroque shapes used in classic or modern necklaces, bracelets, and earrings.
- Colorful gemstones and vivid pearls are gaining more popularity in the German market since the COVID-19 crisis, as they attract attention and enhance one's image during online conversations. Popular gemstones include rubies, sapphires, and emeralds.

Breuninger
Furthermore, the Pantone Color Institute has announced new color trends for the year 2023, such as the color Viva Magenta, a vibrant reddish hue that balances warmth and coolness.

Mrs. Leatrice Eiseman, the institute's executive director, explained that this color trend reflects courage, strength, vitality, fun, and readiness for new adventures. This color tone can be seamlessly incorporated into jewelry designs, watches, and accessories. Currently, designers and manufacturers are introducing jewelry designs in vibrant colors following the Viva Magenta trend, such as Le Carré, Annamaria Cammilli, and Sabine Müller companies.

Opportunities for Thai Jewelry and Accessories in the German Market

1) Thailand is considered a significant source of jewelry and components, especially gold, silver, and colored gemstones, which have been increasingly popular in the German market. This presents an opportunity for exporters who can offer products tailored to market demands. Importers view Thai products as high-quality, reasonably priced, and Thai entrepreneurs as reliable. Importers often travel to Thailand during jewelry exhibitions and holiday festivals to seek products.

2) Importers appreciate and admire the craftsmanship of Thai artisans, particularly in crafting intricate and delicate jewelry settings. Currently, many jewelry companies abroad commission jewelry settings from Thailand and even establish partnerships for production bases in Thailand. Therefore, developing artisan skills in the jewelry sector can enhance industry quality and maintain good standards.

3) Thai jewelry designs are beautiful and diverse, ranging from classic to contemporary styles. Manufacturers can quickly adapt to market trends. Moreover, Thailand's jewelry industry continues to see emerging entrepreneurs and designers, making it an attractive choice for foreign importers looking for unique and trendy designs.
Imports of Jewelry and Accessories in Germany

Over the past three years, Germany has imported jewelry and accessories from around the world with an annual value of approximately 35,588 million US dollars. After the COVID crisis, Germany's import figures showed clear recovery in 2023, reaching a value of 39,842 million US dollars, an increase of 36.94% from the previous year. However, in 2024, these numbers slightly decreased to 37,829 million US dollars, a decrease of 5%, due to the conflict situation between Ukraine and Russia.

Important statistics on the imports of jewelry and accessories in Germany, categorized by product codes (H.S. Code), can be ranked in descending order by import value as follows:

1) Unprocessed gold (H.S. 7108): Germany imported an average of 8,190 million US dollars annually during 2023-2025. In 2025, imports of this item totaled 8,686.35 million US dollars, a decrease of 7.37% from the previous year (2024 value: 9,377.24 million US dollars).

2) Miscellaneous articles of base metals (H.S. 7112): Germany imported an average of 7,935 million US dollars annually during 2023-2025. In 2025, imports of this item totaled 8,206.98 million US dollars, a decrease of 10.25% from the previous year (2024 value: 9,144.2 million US dollars).

3) Platinum (H.S. 7110): Germany imported an average of 6,791 million US dollars annually during 2023-2025. In 2025, imports of this item totaled 6,821.96 million US dollars, a decrease of 21.27% from the previous year (2024 value: 8,665.36 million US dollars).

4) Various coins (H.S. 7118): Germany imported an average of 4,056 million US dollars annually during 2023-2025. In 2025, imports of this item totaled 4,840.47 million US dollars, an increase of 34.79% from the previous year (2024 value: 3,591.15 million US dollars).

5) Genuine jewelry (H.S. 7113): Germany imported an average of 1,720 million US dollars annually during 2023-2025. In 2025, imports of this item totaled 1,880.85 million US dollars, an increase of 9.31% from the previous year (2024 value: 1,720.7 million US dollars).

Export from Thailand to Germany

During the years 2023-2025, Thailand exported jewelry and accessories to Germany with an average value of 564 million US dollars annually. The export rate has consistently increased over this period.

In 2025, Thailand's exports of these products to Germany totaled 571.9 million US dollars, an increase of 1.63% compared to the previous year. These exports can be categorized by product codes (H.S. Code) from highest to lowest value as follows:

1) Genuine jewelry (H.S. 7113): In 2025, Thailand exported a total value of 473 million US dollars to Germany, a decrease of 1.94% compared to the previous year. Germany ranks as Thailand's 2nd trading partner, following the United States.
   1.1) Jewelry made of precious metals (H.S. 711311): In 2025, Thailand exported a total value of 417.46 million US dollars to Germany, a decrease of 4.63%. Germany ranks as Thailand's 2nd trading partner for this category.
   1.2) Jewelry made of other valuable metals (H.S. 711319): In 2025, Thailand exported a total value of 56.19 million US dollars to Germany, an increase of 24.06%. Germany ranks as Thailand's 11th trading partner.
   1.3) Jewelry made of metals (H.S. 711320): In 2025, Thailand exported a total value of 28,998 million US dollars to Germany, a decrease of 19.31%. Germany ranks as Thailand's 10th trading partner.

2) Precious metal articles (H.S. 7112): In 2025, Thailand exported a total value of 66.33 million US dollars to Germany, an increase of 22.04%. Germany ranks as Thailand's top trading partner.

3) Gems (H.S. 7103): In 2025, Thailand exported a total value of 17.45 million US dollars to Germany, an increase of 58.34%. Germany ranks as Thailand's 11th trading partner.

4) Artificial gemstone jewelry (H.S. 7117): In 2025, Thailand exported a total value of 7.68 million US dollars to Germany, an increase of 2.24%. Germany ranks as Thailand's 11th trading partner.

5) Platinum (H.S. 7110): In 2025, Thailand exported a total value of 4.63 million US dollars to Germany, an increase of 7.94%. Germany ranks as Thailand's top trading partner. @chapter:32 @chapter:3 @chapter:32


# Publication Year: -
# Title: Secrets of a Master Gem Cutter
# Abstract: Michael M. DyberLedge Art Studio

	Interview with Michael M. Dyber, Ledge Art Studio
It may not be too much of a stretch to compare what Michelangelo did with marble and Rodin did with bronze to what Michael Dyber does with gemstone. For more than two decades, former plumber, welder and jewelry store-owner Dyber has been dazzling the world with his brilliant stone carvings ranging from sizes that fit in the palm of the hand to 12-lb quartz behemoths that can dominate a room.

Dyber is every bit the artist as legend would have it. He started sculpting gemstones without prior training, money, or reputation, and within two years had announced himself on the world stage at the Idar-Oberstein, Germany, precious stone carving competition, where he became the first American to be so highly recognized. His relentless drive to reinvent himself to keep ahead of his imitators has led Dyber to such gem-carving breakthroughs as his “Dyber Optic Dishes,” where concave impressions on the pavilions of his materials create illusions of impossible images in his works.

Dyber loves the challenge of working with exotic two-color ametrine and four-color quartz with handmade tools fashioned from commonplace raw material found around his house. In this video he offers his secrets on turning carpenter nails into drills and beech trees into wheels to approximate the tools carvers used centuries ago.

In the video Dyber also provides valuable insights on the modern colored stone market, wisdom on what makes an artist, and sage advice for the creative soul wherever its aspirations lead. The 2013 Tucson Gem Show where this interview took place gave us the opportunity to tap into the mind of one of the unique talents in modern art, and it is with great pride that we present it here. @chapter:33 @chapter:2 @chapter:33


# Publication Year: 2023
# Title: Characteristics of Treated Rubies from Greenland
# Abstract: Figure 1. Greenland’s rubies are characterized by abundant twinning planes. The twinning planes are not altered by the treatment at a larger scale, but features associated with the twinning can be significantly affected by heating. Photo by S. Wongchacree; field of view 14.40 mm.
Rubies and pink sapphire from Greenland are a new addition to the trade. The deposits have been known for decades, but only in the last three years have the finished gems become available in the market. The vast majority of the material is mined by the company Greenland Ruby and disclosed as treated. The habits of the rough corundum crystals are tabular, barrel, or rounded in shape. Their color ranges from dark red to very light pink, with a varying purplish or grayish cast.
Since the stones are mined from a primary deposit, they are often attached to other minerals. Most are mechanically removed at the mine site during the highly automated sorting process. At Greenland Ruby’s treatment facility, some stones might be further manually trimmed or clipped to remove more of the matrix. Next, the rubies and pink sapphires are intensely cleaned with strong acids. These dissolve most minerals but do not affect the corundum. Lime is used to neutralize the acid, sometimes leaving a thin white coating on the rough stones.
After cleaning, the stones are heated with flux in crucibles and heated in electric furnaces for multiple hours at high temperatures (>1500°C). This method improves the clarity by healing thin fractures. Excess flux covers the rough stones in a thin glassy layer. After cooling, this product is polished as cabochons or beads. Higher-clarity pieces are faceted. The small amount of corundum produced by artisanal miners is treated in a similar fashion, but their exact procedures are not known.
Inclusion scenes of untreated stones are described in C.P. Smith et al. (“Ruby and pink sapphire from Aappaluttoq, Greenland,” Journal of Gemmology, Vol. 35, No. 4, 2016, pp. 294–306) and K. Thirangoon (“Ruby and pink sapphire from Aappaluttoq, Greenland: Status of ongoing research,” GIA Research News, March 23, 2009). These studies highlight the unique and exotic suite of crystal inclusions, including sapphirine and cordierite. We were able to complement these earlier works by studying some of the high-grade material recently produced by Greenland Ruby that has been treated. This is a very intense treatment procedure that significantly alters the inclusion scenes of Greenland’s rubies and pink sapphires.

Figure 2. A: The Rose channels take on a more spotted appearance and can have multiple partially healed fractures around them; field of view 1.44 mm. B: This crystal was completely destroyed; all that remains is a cottony “snowball” inclusion; field of view 1.80 mm. C: All of the inclusions in this cluster developed partially healed fractures around them; field of view 3.60 mm. Photomicrographs by S. Wongchacree (A) and C. Khowpong (B and C).
The most obvious internal features are linked to the omnipresent twinning in corundum from Greenland (figure 1). The twinning planes themselves are not altered by the treatment. The so-called Rose channels, which are hollow tubes at the intersection of twin planes, do show changes. Small fractures, often healed, develop around the linear features, while the tubes themselves usually take on a more spotted appearance when viewed at higher magnification (figure 2A).
Most crystal inclusions show strong alteration, as expected for high-temperature treatment. This makes the unique inclusion scene of Greenland ruby and sapphire unrecognizable. Many of these inclusions transform into “snowballs” with a white frosty opaque nature, often accompanied by discoid fractures that can show signs of healing (figures 2, B and C). In rare cases, crystal inclusions such as zircon remain unaltered.

Figure 3. Left: The particles often appear as a mix of short needles, arrowheads, and more irregular shapes. Illuminating them requires the right orientation of the eye, particles, and light source. Right: Dense clouds of finer particles are occasionally found in Greenland rubies. Photomicrographs by C. Khowpong; fields of view 2.40 mm (left) and 2.88 mm (right).
Less common in Greenland rubies are particles and platelets. Since they require a correct alignment of the observer, platelet, and light source to be detected, they are often overlooked. The particles are a mix of elongated and irregularly shaped platelets. Some could be described as short, stubby needles resembling arrowheads (figure 3, left). They can also appear in dense clouds of finer particles with a roughly hexagonal outline (figure 3, right). These look very similar to the features observed in East African rubies from Mozambique and Madagascar, where they are very common. These seem to be only subtly affected by the treatment. In rare cases, the platelets take a roughly hexagonal form with concentric brightness zoning, resembling a fried egg “sunny-side up.” These may be reminiscent of inclusions typically associated with Thai rubies, although Thai rubies almost never show the presence of other particles. We suspect that the unique appearance of these platelets is due to the intense heat they have been subjected to.

Figure 4. A: This healed fracture has irregular droplets of flux that were trapped during healing. They stand out due to their high relief and more translucent appearance; field of view 2.88 mm. B: Connecting networks of trapped flux in a healed fracture; field of view 2.80 mm. C: Not all fractures were able to heal to the same degree. Swirling droplets of trapped flux and air reveal that a large portion of this fracture is actually filled with solidified flux rather than healed corundum; field of view 1.20 mm. Photomicrographs by C. Khowpong (A and B) and S. Wongchacree (C).
Apart from the twinning features, the most obvious features in the treated stones are flux-healed fractures. These are caused entirely by the treatment and are diagnostic of flux healing. As such, they are completely unrelated to a specific origin. Remnants of the flux trapped in the healing fracture can appear as small irregular droplets or connecting worm-like tubes (figure 4, A and B). These might bear some resemblance to natural fingerprints, but they usually have a coarser appearance with more translucent whitish patterns. When the healing is incomplete, the flux can be present in the fractures as a glassy substance showing swirling patterns and trapped gas bubbles (figure 4C).
The treatment has no impact on the corundum’s trace element chemistry. The composition of the studied suite is in line with the data reported in Smith et al. (2016). The only values that show some deviation are the titanium concentrations, which are lower in the samples analyzed in this study (12–102 ppmw vs. 81–1227 ppmw in Smith et al.). This might be explained by the higher quality of the samples and thus the absence of cloudy, rutile-rich zones that have higher titanium concentrations. As mentioned in earlier studies, the trace element composition of these stones can overlap with rubies that form in amphibolites, which are commonly encountered in East Africa (mostly Mozambique and Madagascar).
Heat treatment with added flux clearly has a significant impact on the overall appearance and can be easily detected by the multitude of healed fractures. The treatment does alter some important internal features that can complicate origin determination. @chapter:16 @chapter:0 @chapter:16


# Publication Year: -
# Title: Video Feature: Emerald Sources of Brazil
# Abstract: Emerald Sources of Brazil Sergio Martins, Stone World

	In these videos, Sergio Martins, president of the Brazilian gemstone cutting and marketing firm Stone World, gives an overview of Brazil’s most important emerald deposits, as well as the country’s mining practices and laws.
Brazil is a major supplier of emeralds for the global market. There are a few important mining areas, and the emeralds produced at each location can have different characteristics. Overall, the supply of Brazilian emeralds remains relatively stable, despite fluctuations at individual mining locations.

	Mining Areas
The mines in the state of Bahia were among Brazil’s first emerald-producing locations, dating back to the 1960s. They continue to supply large quantities of emerald to the global market. In Bahia, there is a large production of carving, cabochon, bead, and commercial-quality facet-grade material.

In the state of Goiás, the area near the town of Santa Terezinha de Goiás has yielded large quantities of emerald, primarily in smaller crystal sizes.

The mining areas near Itabira and Nova Era in the state of Minas Gerais generate the most consistent and highest-quality supply of Brazilian emeralds. Itabira is the more stable producer, while Nova Era is known for very large emerald crystals. Montebello is one of the largest and most sophisticated mines in Nova Era. Belmont is a modern operation and an important global supplier on a steady basis. The Belmont mine often cuts its own better-quality emeralds, moving it up the value chain into cut goods. Between Belmont and Nova Era mines lies a newer mine, Piteiras. Though currently closed, it could be reopened and become an important source.

In addition to the established emerald mining areas, new production has started in the state of Rio Grande do Norte under the colored stone mine-to-market legend Lorenzo Yih.

	Mining Methods
Brazilian emeralds are extracted by mechanized mines such as Belmont, which use the most sophisticated techniques, and by cooperatives of independent miners, financed by investors. These independent miners, known as garimpeiros, use unsophisticated methods to recover gemstones or other minerals such as gold. They perform hard manual labor in search of the treasure that will change their lives. @chapter:1 @chapter:0 @chapter:1


# Publication Year: 2015
# Title: Diamond Slices
# Abstract: Figure 1. These AGTA Spectrum Award–winning earrings, designed by Michael Endlich, incorporate three matched pairs of diamond slices totaling 7.07 carats into a platinum setting. Photo courtesy of Michael Endlich.

Gem and mineral slices were very popular at this year’s Tucson shows, with opaque, translucent, clear, included, rough-edged, and finely shaped slices found in every color and price point. Materials such as fossilized coral, rutilated quartz, lacy agates, labradorite, chalcedony, watermelon tourmaline, sapphire, and diamond were on display. A wide variety of sizes were available as well, with pieces measuring several centimeters in diameter finding their way into dramatic necklaces, while some high-end jewelry and collector pieces used extremely thin and small gem slices.

Notably, the third-place winner in the bridal category of the 2015 AGTA Spectrum Awards was a pair of platinum and diamond earrings designed by Michael Endlich, featuring three pairs of diamond slices in addition to several pavé-set diamonds (figure 1). Endlich finds this gem material unusual, exciting, and subtle. Most of his clients have never seen these slices and are fascinated once they realize they are looking at diamonds. He goes through thousands of slices to select those he will incorporate into pieces. He particularly likes slices with patterns, such as concentric squares. This material is relatively new to the marketplace, and he first came upon it six years ago. Even though more diamond dealers offer them today, few slices have the distinct patterns Endlich looks for.

At the GJX show, Punya Malpani (Dynamic International, Hong Kong) discussed the diamond slice market with us and shared some particularly eye-catching and rare examples. He noted that the price of these goods has gone up approximately 20× in the past decade, as jewelry designers continue to go beyond traditional faceted gem shapes. There is also a strong collectors’ market for this material, as the unique nature of each piece adds to its appeal. In fact, there are very few larger slices of diamond in the marketplace, because the outer “skin” from the rough material was generally discarded before this niche market was identified. Unlike faceted diamonds, inclusions increase the value of slices, especially if they are unusual, striking, and highlight growth patterns.

Diamond slices today are mainly cut by laser and can vary widely in diameter and thickness, though diameters greater than one centimeter are difficult to come by, as rough in that size is much rarer. Many slices are slightly faceted to add some sparkle to the finished piece. Most of the diamond slices maintain the rough outline, as this can add to the appeal, but some are shaped into fanciful and matched sizes such as the “snowflakes” Malpani showed us.

Three-rayed “trapiche” diamond slices are among the most scarce and striking, as they contain a recognizable radiation-symbol pattern (figure 2). These are only found about once in a couple of thousand slices, and even then it is rare to find distinct coloring. The collection shown in the photo took years to assemble.

Figure 2. The three-rayed “trapiche” pattern is found in less than 0.1% of diamond slices, and rarely is it so distinct. The collection of nine slices, including these four samples, took years to assemble. Photo by Jennifer Stone-Sundberg, courtesy of Dynamic International.
Malpani’s most prized slices are the matched pair of large colorless diamond slices with dramatic white patterning (figure 3). These two pieces, separated from a skin cut of a large piece of rough, date back about 20 years. This is unusual, as such slices were not retained in the past.

Figure 3. These two large colorless diamond slices from the same piece of rough show dramatic patterning. Photo by Duncan Pay, courtesy of Dynamic International.
It appears that the use of gem slices in jewelry has penetrated the high-end market. Since diamond is clearly a prominent material capitalizing on this gem “cut” with natural appeal, we can expect this trend to continue. @chapter:38 @chapter:3 @chapter:38


# Publication Year: -
# Title: The Rise of the Brazilian Jewelry Industry
# Abstract: The natural and cultural elements of Rio de Janeiro influence many jewelry designers.

                      I have traveled to Brazil many times over the last decade and witnessed tremendous changes there, including significant increases in its economic power and industrial development, and the emergence of women professionals. Accompanying these trends has been the rise of an incredible jewelry design and manufacturing industry.

At the August 2012 Feninjer show in São Paulo, I witnessed the full spectrum of Brazilian jewelry design. And while viewing the styles on display at the show is very informative, to see them actually being worn by Brazilians helps you understand the jewelry’s cultural connection.

	Brazil’s jewelry reflects the sense of style possessed by its women. Like Brazilian fashion and style, the jewelry is often bold. Photos courtesy of Vianna Joais (left) and Manoel Bernardes (right).
Designers in São Paulo, Belo Horizonte, and other cities are dedicated to capturing important elements of the domestic culture, creating styles that are uniquely Brazilian. The culture of Brazil is extremely rich and diverse. Portuguese settlers, indigenous societies, and Africans imported through the slave trade all contributed their own unique cultures. This cultural blend created a unique style.

	Afro-Brazilian culture has a strong influence on design.
Besides cultural diversity, Brazil is also known for its natural beauty, from the lush jungles of the Amazon to the picturesque beaches and mountains and the incredible variety of flora and fauna. Brazilian jewelry always seems to reflect these design inspirations.

	Brazil is a country full of natural wonders, such as Iguazu Falls, that inspire jewelry designs.
Another contributing factor is the wealth of gemstones available there. Brazil is one of the most significant producers of a variety of colored gemstones, which are often incorporated into these jewelry designs. The liberal use of gemstone color creates a bold look.

	Cultural aspects such as music and dance are sometimes reflected in Brazilian jewelry designs. Courtesy of Vianna Joais.
The cost of mining and cutting gemstones has risen steadily along with Brazil’s economy. Labor costs and government regulations have added significantly to operational costs, especially in the mining sector. For some mining operations, it is no longer being economically viable to produce certain gemstone varieties for the international market.

International gemstone trading is usually done in U.S. dollars, which has created a sort of double penalty. As business costs have risen, so has the value of the Brazilian real against the U.S. dollar. As a result, it now costs considerably more to mine and cut gemstones in Brazil, and they receive less dollar value when they’re sold.

As costs have risen, many Brazilian companies have thrived by moving up the value chain into branded finished jewelry. Their uniquely Brazilian style incorporates many different domestic gemstones. The high value of the jewelry makes gem mining and cutting profitable again and creates new employment opportunities.

	Brazilian jewelry designs are usually incorporated into matching suites. Courtesy of Vianna Joais.
Manoel Bernardes has been a wholesale colored stone supplier for decades. The majority of its business is now in branded finished jewelry, which completes for them the entire mine-to-market supply chain. The company also has its own retail stores in Brazil. Vianna Joais is another company with brand power in Brazil and, through its exports, around the world. Its jewelry designs and suites incorporate a wide variety of colored stones.

	Earth tones signify the strong connection between Brazilians and their environment. Courtesy of Manoel Bernardes.
Brazilian designers are known for combining colored stones to create a rainbow of attractive colors in a single piece. This look has been very popular with the domestic market and is one of the Brazilian style themes recognized worldwide, thanks to a growing export market.

	Brazilian designs often incorporate a variety of gem colors in a single piece. Courtesy of Vianna Joais.
One key factor in all this is the Brazilian woman herself. She has a unique sense of style that is modern, fashionable, and versatile. She prefers jewelry that blends with nature, evoking a sense of free-flowing movement. Earrings that dangle are a favorite.

	Pastel colors are also a popular choice. Courtesy of Vianna Joais.
Brazilian women love both intense and pastel colors in gemstones. They often wear large stones or pieces with combinations of different stones. The wealth of stones includes aquamarine, morganite, blue topaz, yellow to imperial topaz, amethyst, citrine, green quartz, smoky quartz, rose quartz, various colors of tourmaline, rhodonite, iolite, and others.

	Brazilian women often incorporate large pieces of jewelry into their fashionable wardrobes. Courtesy of Manoel Bernardes.
The Brazilian consumer often goes for the color rather than the higher-priced gemstones. While Brazil is a major source of emeralds for the world market, they are not among the more popular gemstones used in Brazilian branded jewelry, especially for the domestic market. Besides favoring less-expensive colored gemstones, Brazilians also make jewelry purchases and change styles more often than many other consumers. Many Brazilian jewelry designers come out with four brand-new collections a year. Because of domestic demand, this is almost a necessity. New jewelry lines often come out each season, to coordinate with the fashions Brazilian women will be wearing. Floral designs are especially popular in spring and summer.

	This design incorporates floral motifs and dangling gems. Courtesy of Vianna Joais.
For brands such as Vianna Joais and Manoel Bernardes, vertical integration offers a great deal of design versatility. They are not confined to styles that use standard gemstone shapes and sizes. They can create asymmetrical shapes and non-standard sizes and incorporate them into their brilliant designs, while still producing sufficient quantities to create entire seasonal jewelry lines.

	While Brazilian designers are known for taking advantage of the full rainbow of gem colors, they also incorporate neutrals. Courtesy of Vianna Joais.
This design philosophy also offers an economic advantage that helps offset the rising production costs. If rough gems from the mine are elongated, or have some other shape that would result in substantial weight loss for standard cuts, the designers can incorporate them in a way that retains a larger percentage of the stone’s original weight.

While 18K yellow gold is the standard metal for Brazilian jewelry, 18K white and rose gold have been gaining popularity. Silver has also become more important, partly because its lower cost helps maintain the right price points for the domestic market.

Brazilian jewelry makers can compete against lower labor costs elsewhere by incorporating unique designs and frequently introducing new lines. The manufacturing equipment and techniques are also constantly being updated and refined.

	Today, many of Brazil’s very talented and artistic jewelry designers are women.
Besides the Feninjer show for designers and manufacturers selling to retailers, I also attended Techno Gold in São Paulo earlier in 2012. Techno Gold was aimed primarily at Brazilian jewelry manufacturers, and state-of-the-art equipment was displayed and sold at the show.

	Many Brazilian jewelry brands have their own lapidary facilities where they can cut stones to any shape needed for their designs.
The future of the Brazilian designer jewelry industry looks very promising. The country’s vast gem wealth lends itself to custom jewelry designs with an innovative style that incorporates Brazilian culture and natural beauty. Colored stone suppliers have offset higher costs by moving up the value chain into finished jewelry, satisfying the domestic market while also branding their style internationally. Meanwhile, trade organizations such as the Brazilian Institute of Gems and Precious Metals (IBGM) sponsor design contests and conduct some 80 training programs across the country, preparing the next generation of jewelry innovators.

	Brazilian designs often combine pastel-colored gemstones with darker or more intense varieties. Courtesy of Vianna Joais. @chapter:45 @chapter:2 @chapter:45


# Publication Year: 2022
# Title: Treated Orange and Pink CVD Laboratory-Grown Diamond
# Abstract: Figure 1. These 2.00 ct Fancy Deep orange (left) and 3.00 ct Fancy Vivid orangy pink (right) CVD-grown diamonds were subjected to multiple treatments including HPHT processing, irradiation, and low-temperature annealing to achieve the final color grades. Photos by Diego Sanchez (left) and Sood Oil (Judy) Chia (right).
Recently, GIA received two similarly treated diamonds grown by chemical vapor deposition (CVD): a 2.00 ct Fancy Deep orange and a 3.00 ct Fancy Vivid orangy pink (figure 1). A database search revealed that the Fancy Deep orange was the first CVD-grown diamond with an unmodified orange color ever submitted to GIA. CVD-grown diamonds with an orangy pink color are far more common, and the 3.00 ct sample provided for an interesting comparison. From examination of the visible/near-infrared (Vis-NIR) absorption spectra, both samples had similar features and likely underwent similar treatment processes (figure 2). The subtle differences in relative peak intensities were sufficient to create the distinctly different appearances and color grades.

Figure 2. The 2.00 ct Fancy Deep orange and the 3.00 ct Fancy Vivid orangy pink CVD-grown diamonds underwent similar post-growth treatments and show similar defect centers in their Vis-NIR absorption spectra, including the NV centers, 594 nm, SiV–, and GR1. However, subtle differences in relative defect concentrations lead to their distinct color appearances. Although very small, the GR1 defect was also detected in the absorption spectrum of the 2.00 ct CVD-grown diamond. Spectra are offset vertically for clarity.
The Vis-NIR absorption spectra for both CVD-grown diamonds showed nitrogen vacancy centers (principal absorption for NV0 at 575 nm and NV– at 637 nm), 594 nm peak, and the GR1 center. Both samples also displayed strong absorption of the SiV– center (737 nm). In the Fancy Deep orange sample, the NV centers exhibited lower absorption than in the orangy pink sample and also a slightly greater SiV–-related absorption, which helped shift the transmission window from the red (i.e., pink) toward the orange.
Based on the comparatively low value of the 468 nm emission peak determined by 457 nm photoluminescence spectroscopy, both CVD-grown diamonds showed evidence of high-pressure, high-temperature (HPHT) treatment; they were subsequently irradiated to generate the radiation-related features that included the 594 nm peak and the GR1 center. Irradiation was followed by low-temperature annealing, which was intended to generate additional NV centers without fully annihilating the GR1 center. The 594 nm center is a radiation-related defect in nitrogen-containing diamonds. In the IR absorption spectra of both CVD-grown diamonds, small peaks at 1344 cm–1 were observed. From those peaks, the single nitrogen concentration could be estimated as ~1 ppm (S. Eaton-Magaña and J.E. Shigley, “Observations on CVD-grown synthetic diamonds: A review,” Fall 2016 G&G, pp. 222–245).
Both samples presented red fluorescence when excited by the deep UV wavelengths of the DiamondView, a feature that is consistent with the strong nitrogen-vacancy centers in these CVD-grown diamonds. However, neither sample showed any noticeable photochromic effects from the deep UV exposure, something that can occur in CVD-grown diamonds due to charge transfer of the NV centers or the SiV– centers (S. Eaton-Magaña et al., “Laboratory-grown diamond: A gemological laboratory perspective,” Journal of Gems and Gemmology, 2021, Vol. 23, No. 6, pp. 25–39).
The Fancy Deep orange sample was interesting to observe, as unmodified orange colors are extremely rare among natural diamonds and, until now, laboratory-grown samples. Subtle engineering of defect concentrations during post-growth treatment can lead to vastly different results in the color grades. @chapter:9 @chapter:1 @chapter:9


# Publication Year: -
# Title: Bench Tip #3: Discover the Benefits of CAD CAM
# Abstract: Discover the benefits of CAD/CAM

CAD/CAM is a term that describes the two-part process of designing three-dimensional objects on a computer (CAD) and manufacturing them with a computerized machine (CAM). For many years this technology has been essential in making products from tennis shoes to automobiles, and it is rapidly gaining importance in the jewelry industry. In fact, many experts believe CAD/CAM will be the primary process of jewelry design and manufacturing in the near future.

CAD is an acronym for computer-aided design, but early on it stood for computer-aided drafting, since it was essentially a tool to make traditional technical drawings with a monitor and a mouse. As technology progressed, it became possible to create three-dimensional “models” within the computer environment. These “virtual solids” can be rotated and manipulated onscreen and examined from any angle, built up and cut away the same as a physical model, and even weighed before they are constructed.

For the bench jeweler, CAD modeling onscreen has more in common with wax carving than with pencil, paper and watercolors. Once the virtual model is completed to the designer’s satisfaction, the CAD file may be sent to a CAM machine for production. Rhino, Matrix, ArtCam, RhinoGold and Solidworks are some of the widely used 3-D modeling software in the jewelry industry today.

The beginning of the modeling process in CAD/CAM. It's easy to add or change elements of a design on the computer.
The advantages of CAD/CAM over traditional manufacturing methods are similar to the advantages of a word processor, such as Microsoft Word, over a typewriter. A typewriter produces “one-off” documents that aren’t easily changeable without starting over. But Word files can be modified easily, copied and pasted into other documents, and saved at each stage for later use.

CAD files can also be copied, changed and saved as often as the designer chooses. A model can be designed and saved, then redesigned to create literally endless variations on a theme. A file can be called up the next day or 10 years later and still be redesigned and sent to the CAM machine. Some manufacturers have stopped making master models since they only need to open the original CAD file and send it to the CAM machine to produce an exact duplicate of the master. Many smaller jewelers own just the CAD software and simply e-mail their CAD files to CAM service bureaus, which fabricate the models for them.

The final design in CAD/CAM.
Besides its advantages in the manufacturing process, CAD software can work in tandem with high-tech rendering software such as V-Ray, Brazil and Maxwell to produce spectacular photorealistic images of virtual jewelry models before the actual piece is made. These images can be extremely effective marketing and sales tools.

A rendering of the design created in CAD/CAM. @chapter:45 @chapter:2 @chapter:45


# Publication Year: 2017
# Title: Cultured Pearl Market Update
# Abstract: Figure 1. The range of necklaces at Mastoloni’s AGTA booth included innovative blends of different cultured pearl types. Photo by Eric Welch; courtesy of Mastoloni Pearls.

At the 2017 AGTA show, Fran Mastoloni (Mastoloni Pearls, New York City) provided a cultured pearl market update. Mastoloni is a 30-year veteran of the Tucson show and well positioned to place the ups and downs of demand in context. There is a real desire for cultured pearls, he says, but people have moved away from the traditional white necklace. Partly this is because cultured pearl sources have become much more diverse in recent years, with French Polynesia, Australia, the Philippines, Indonesia, and China contributing a diverse array of cultured pearl types, shapes, sizes, and colors (figure 1).

Mastoloni’s clients are seeking—and selecting—something different. “They all want a unique necklace,” he says. And since the second quarter of 2016, he’s seen demand pick up considerably. Most clients don’t want to spend a fortune, but they do want the piece they choose to be unique and individual. His job is to create cultured pearl necklaces that meet their needs.

	Fran Mastoloni – Mastoloni Pearls

In this interview, Fran Mastoloni updates us on trends in cultured pearl supply and customer demand. He presents some of the most attractive—and successful—necklace designs and provides insight into which styles people choose and why.
To demonstrate, Mastoloni showed us his “Fantasy” necklace: a standard-length strand combining South Sea and Tahitian cultured pearls with lighter gold ones from Indonesia. This blends a repeating pattern of large (up to 16 mm) eye-catching, semi-baroque pearls with smaller examples—down to 8 mm—to create a large, mixed look. The use of light and dark pearls also confers the ability to use the piece on a variety of clothing colors for day or night use, he added, so it’s very versatile. He added that products must also appeal to female self-purchasers, so the retail price point—less than $2,000 per strand—is an important consideration. This is a very important—if not the most important—market segment for him today.

Mastoloni showed us another successful cultured pearl line for the company, which he dubbed the “Cocktail” necklace (figure 2). It combines Philippine gold pearls, white Australian South Sea, and lighter Tahitian pearls to create a long necklace that can be draped twice. Again, every necklace is individual, so that a customer can “key into” an individual pearl—maybe a large South Sea or Tahitian—and identify that necklace as unique. Examples like these, he explained, transform the concept of what a cultured pearl necklace might be.

Figure 2. The “Cocktail” necklace features a combination of differently sized round cultured pearls: darker Tahitian, golden Philippine, and white Australian South Sea. Photo by Eric Welch; courtesy of Mastoloni Pearls.
Customers are similarly drawn to baroque pearls for their uniqueness. Mastoloni used a variation of the “Cocktail” necklace to illustrate the point, this time with baroque pearls ranging from 16–17 mm plus down to 9 mm. The organic shapes bring texture and movement to the piece and “make it fun.”

Figure 3. This necklace features 14 mm round Tahitian cultured pearls in the front and 9 mm South Sea “keshi.” Photo by Eric Welch; courtesy of Mastoloni Pearls.
The next necklace he showed us blended 9 mm baroque white South Sea “keshi” pearls with 14 mm dark Tahitian round cultured pearls, creating two transitions: from light to dark and from organic shapes to regular, round ones (figure 3). A customer might own all three of these necklaces, he said, and use them for different occasions.

Also popular are variations on the wave necklace, which blends a uniform strand of round white Japanese akoya cultured pearls with “waves” of graduated silvery black Tahitian cultured pearls that swell and pinch out against the white of the akoyas. The mix of the different cultured pearl types working together is what makes these designs so successful. They’re the kind of “fashion-forward” pieces that stylish but price-conscious consumers pick out, he says.

Of course, sourcing pearls for all these necklaces is always a challenge for Mastoloni. One of his key considerations is maintaining standards. For the “Cocktail” necklaces he has to source pearls of the same tone, color saturation, and luster. You just can’t throw pearls together and expect them to look good, he explained. It requires an understanding of the product along with consistency in both quality and look—as well as an enormous amount of pearls.

Mastoloni asked us to look at professional women of power on television, who frequently wear significant pearl necklaces. Their choice might be a necklace combining different pearl colors, or a uniform one with large round white South Sea or Tahitian cultured pearls. Fine pearls can be worn in the boardroom or at social gatherings—they show that the wearer “has arrived.” No other jewelry is as versatile.

Mastoloni noted that the supply of Tahitian cultured pearls has changed. Although there looks to be a good variety of subtle colors, he’s not seeing the same wide range of colors as 10–15 years ago. This appears to be because the culturing process is improving and there is more control over color consistency. This is better from the point of view of investors, because consistent colored pearls are easier to match and sell. As a result, those investing in pearl cultivation find it easier to recoup their expenses.

Next, he showed us single pearls and collection pieces, starting with a 23.3 × 28.6 mm Australian baroque South Sea pearl that was solid and unblemished on all its surfaces. Single pearls like this one are unique items that a person can make their signature piece—something they wear every day.

Pairs, such as the 15.0 × 18.5 mm Tahitian cultured pearls seen in figure 4, are also perfect for unique pieces. Their light pistachio color is one of the colors Mastoloni used to love but can no longer easily obtain. Serendipitously, he found a matching-color larger drop shape measuring 16.0 × 22.7 mm to make up a trio (again, see figure 4). According to Mastoloni, the right designer could make an incredible piece out of these.

Figure 4. A pair of 15 × 18.5 mm light pistachio Tahitian cultured pearls. A matching-color
drop shape measuring 16 × 22.7 mm makes up a trio. Photo by Eric Welch; courtesy
of Mastoloni Pearls.
His next piece was a 16 × 23 mm Tahitian drop pearl with a unusual shape and excellent luster. It was a near-perfect teardrop with a very attractive slightly asymmetrical tip, shaped almost like a drop of water. It begs attention, he explains, a pearl like this could be the center of attention in a one-of-a-kind necklace. Mastoloni confirmed that such teardrop-shaped pearls are now difficult to find in Tahitian production. As pearl culturing techniques improve, drop pearls are nowhere near as desirable—or as profitable to produce—as spherical ones. Pearl farmers are more concerned with return on investment, so they are really striving to produce more round pearls. As pearl culturing methods improve, consequently, it becomes harder and harder to find nice teardrops—producers make a lot of less attractive, misshapen examples which bring down the value of the harvest.

Finally, Mastoloni showed us a top-quality pair of 15.3 mm round golden pearls. He noted that golden pearls—which are generally produced from the gold-lipped oyster in the Philippines and Indonesia—are still a good business, with much stronger demand in Asia than in the U.S., although the market probably peaked about a year ago. He notes that there might be a little oversupply in Asian markets, but he expects it to be temporary. As far as quality is concerned, Mastoloni’s advice is to look for a pearl that has a good “gold” color—he always likens it to a “ring color”—“you don’t want yellow and you don’t want green, but it’s got to have a richer gold to it,” he says. Indonesia is always going to have a steady supply of pearls, because cultivation takes place over such a large area, he says but cautions that there’s so much champagne and creamy greenish yellow production that he cannot use. He notes that their supply is getting better, but it’s not quite there yet. In his opinion, cultivators in the Philippines are excellent at producing gold pearls, as their waters and their oysters are better suited for these products. Indonesia will continue to produce all colors, and Australian pearl farmers will concentrate on white, while those in Tahiti focus on the different shades and nuances of black pearls. @chapter:56 @chapter:2 @chapter:56


# Publication Year: 2022
# Title: Large, Rare Faceted Collector Gems
# Abstract: Figure 1. A 7.36 ct colorless, modified triangular brilliant-cut colemanite displayed at the AGTA show. Photo by Emily Lane; courtesy of Barker & Co.
Barker & Co. (Scottsdale, Arizona) exhibited remarkable stones at this year’s AGTA show, including some extremely fine, rare gemstones for collectors. Two of their collector stones, colemanite and phosphophyllite, stood out for their record-breaking size.
The colorless colemanite in figure 1, a modified triangular brilliant weighing 7.36 ct, is believed to be one of the largest faceted examples of its kind. Colemanite is known to fluoresce a strong yellow under ultraviolet light and phosphoresce green.
The strongly saturated bluish green hue of a 17.52 ct phosphophyllite echoed that of some of the finest hues of Paraíba tourmalines, though the stone is very different both structurally and chemically. Phosphophyllite was named in 1920 as a homage to its phosphate composition and perfect leaf-like cleavage (from the Greek phyllon, meaning “leaf”). Ann Barker of Barker & Co. explained that this particular phosphophyllite has a significant provenance. Once owned by author and renowned mineral collector Dr. Peter Bancroft, it was mined in the famed Potosí mine of Bolivia in 1958. Many years later, prize-winning gem cutter Stacy Whetstone took the striking 45.42 ct rough and expertly faceted the material into the finished 17.52 ct rounded trillion (figure 2). Given phosphophyllite’s considerable heat sensitivity, the gem took four weeks to cut and finish.

Figure 2. The evolution of a 45.42 ct rough phosphophyllite in the hands of Stacy Whetstone (left). It took four weeks to cut and finish the stone due to its heat sensitivity (center). The finished 17.52 ct bluish green, modified triangular brilliant-cut phosphophyllite was displayed at the AGTA show (right). Left and center photos courtesy of Barker & Co.; right photo by Emily Lane.
Colemanite and phosphophyllite, like other collector stones, are seldom faceted due to their low hardness (4.5 and 3–3.5, respectively) and durability issues. As collector stones, they hold a unique position in the gem and jewelry industry, valued for expanding private collections. In recent years, with the help of a little luck and a lot of talent, collector stones are being seen more in jewelry. @chapter:1 @chapter:0 @chapter:1


# Publication Year: 2019
# Title: New Find of Deep Blue Aquamarine from Nasarawa State in Nigeria
# Abstract: Figure 1. Nigerian aquamarine from a new find in Nasarawa State. The faceted stones range from 1.55 to 2.63 ct. Photo by Kevin Schumacher.

The most unusual and exquisite things are often found in unexpected places. This has been seen in the explosion in gem discoveries in East Africa since the latter part of the twentieth century. However, West Africa has remained relatively underexplored, despite the development of some promising and productive gem deposits, including sapphire and Paraíba tourmaline in Nigeria. West Africa’s gemological horizons expanded earlier this year with the find of a small batch of aquamarine with exceptionally deep and saturated color (figure 1). Reportedly found in Nasarawa State, the stones were recovered by small-scale artisanal miners whose workings reached only the near-surface exposure of a weathered pegmatite body. Mining was short-lived, starting likely in January and ending in May 2019, when the miners exhausted the surface deposit but lacked resources to continue with hard-rock mining once they hit bedrock. Through a local buyer in the Abuja market, author JH was able to obtain a large parcel that may account for the lion’s share of the production from this deposit to date. This parcel amounted to 763 grams, of which 200 grams would cut stones over one carat.

Figure 2. Two wafers of the new Nigerian aquamarine in unpolarized light (left), and with light polarized along the extraordinary ray (center) and along the ordinary ray (right). Photos by Aaron Palke.

Figure 3. UV-Vis-NIR absorption spectra of a polished plate of Nigerian aquamarine showing both the ordinary (o-ray) and extraordinary (e-ray) ray absorption.
Standard gemological testing showed properties consistent with aquamarine, with a uniaxial negative optic character, a refractive index of 1.582–1.590, a birefringence of 0.008, and a specific gravity of 2.71–2.73. The stones were inert under short-wave and long-wave UV light. The most exceptional feature of this new find of aquamarine—besides its attractive, saturated blue color—is its unusually strong pleochroism, going from deep, saturated blue with light polarized parallel to the extraordinary ray to an unsaturated (almost colorless) greenish blue with light polarized parallel to the ordinary ray (figure 2). The origin of this extreme pleochroism is seen in the UV-Vis spectra (figure 3), in which the main feature is a highly polarizable broad absorption band at approximately 680 nm caused by Fe2+-Fe3+ intervalence charge transfer (IVCT). This IVCT absorption is the cause of blue coloration in (non-Maxixe) aquamarine (e.g., I. Adamo et al., “Aquamarine, Maxixe-type beryl, and hydrothermal synthetic blue beryl: Analysis and identification,” Fall 2008 G&G, pp. 214–226). Also seen are an absorption band at 835 nm related to octahedral Fe2+ and narrow absorption bands at 372 and 428 nm related to octahedral Fe3+. The reason for the intense pleochroism is simply the increased intensity of the highly polarizable Fe2+-Fe3+ IVCT chromophore relative to most other aquamarine. Note that the two wafers in figure 2 were cut from the same piece of rough and were used in a pilot heat treatment experiment. The larger one on the left was not heated, while the smaller piece on the right was heated at 400°C for two hours, with no apparent change in its color or appearance. It is not clear, however, if any of the material had been heated before it reached the market; further experiments may be warranted.

Figure 4. Needle and platelet inclusions are ubiquitous in this new find of Nigerian aquamarine, as seen with transmitted light polarized along the o-ray (left) and e-ray (right). Photomicrographs by Nathan Renfro; field of view 1.43 mm.
Microscopic observations showed an abundance of highly reflective, opaque, elongate needles and platelets that appeared light brown to black in darkfield and transmitted light (figure 4). Confocal Raman spectroscopy could not isolate the inclusions, but their dark color and reflective nature suggest they might be Fe oxides, which would be consistent with the iron-rich nature of these stones.

Trace element content of the Nigerian aquamarines was measured by LA-ICP-MS (table 1). They were extremely enriched in alkali metals, especially Li, K, and Na (up to 9400 ppm). To the authors, these high concentrations of alkali metals seem unusual for gem-quality aquamarine among global deposits (including saturated material from Santa Maria in Minas Gerais, Brazil). The unique chemistry of this new material almost warrants the use of the term “alkali beryl,” even though this term is nonstandard in the mineralogical community. Also notable is the relative enrichment of Cr from 4 to 49 ppm, compared to around 1 ppm Cr or less in aquamarine from most other deposits. The Cr enrichment was also indicated by the prominent Cr fluorescence measured by photoluminescence spectroscopy. Finally, the deep blue color of these stones was explained by their relative enrichment in Fe from 11,000 to 12,600 ppm. Such a high concentration of Fe increases the probability of having adjacent Fe2+ and Fe3+ cations, thereby facilitating and enhancing the Fe2+-Fe3+ IVCT interaction. For now, this new deposit of fine Nigerian aquamarine lies dormant, but the world awaits the next important gem discovery in West Africa. @chapter:6 @chapter:0 @chapter:6


# Publication Year: 2009
# Title: The French Blue and the Hope: New Data from the Discovery of a Historical Lead Cast
# Abstract: A lead cast of the French Blue diamond, a mythic item in the French Crown Jewels, was recently found in the mineral collection of the Muséum National d’Histoire Naturelle (MNHN) in Paris. The details of this diamond—stolen in 1792 during the French Revolution—have up to now been known only from a drawing of an insignia of the Golden Fleece belonging to King Louis XV that was published in 1889 and, more recently, from an unpublished rendering dated as early as 1749. Computer modeling of the French Blue from a laser scan of the lead cast revealed details of the cut that could not be inferred from these drawings. Models of both the lead cast and the Hope diamond confirm that the latter could have been recut from the French Blue. The additional discovery of the catalog entry associated with the lead cast at the MNHN suggests that Henry Philip Hope may have owned the French Blue diamond after its 1792 theft and before it was recut. @chapter:34 @chapter:1 @chapter:34


# Publication Year: 2015
# Title: Demantoid Garnet with Giant Fluid Inclusion
# Abstract: Figure 1. The demantoid crystal from Madagascar contains a giant two-phase fluid inclusion. The photomicrograph shows the FI cavity with its bubble trapped by the garnet. The bubble’s diameter is around 2 mm. Photo by Michel Cathelineau.

Since 2009 the Antetezambato demantoid garnet deposit, near Ambanja, in the Ambato peninsula of northern Madagascar, has yielded a huge quantity of rough gem material. This skarn-related deposit continues to produce fine crystals for the international market in a wide range of colors (F. Pezzotta et al., “Demantoid and topazolite from Antetezambato, northern Madagascar: Review and new data,” Spring 2011 G&G, pp. 2–14). Mineralogical curiosities were also found, such as demantoid garnet fossil pseudomorphs of gastropod and coral (Winter 2013 GNI, pp. 257–258; J. Raoul et al., “Pseudomorphose de fossiles en andradite ‘démantoïde’ à Antetezambato, Madagascar,” le Règne Minéral, Vol. 123, 2015, pp. 21–26). An andradite crystal (figure 1) hosting a giant two-phase (liquid + vapor) fluid inclusion (FI) was extracted from the mangrove swamps and is now the property of M. J. Raoul.

The greenish gem crystal, measuring 1.5 × 0.6 cm (figure 2A), exhibits some faces that follow a more dodecahedral habit {110} while others are more trapezoidal {110}. Micro-Raman spectroscopy clearly showed the four main peaks of andradite at 352, 371, 515, and 874 cm–1 (figure 3, top). The bubble of the FI cavity is visible to the naked eye and moves when the sample is turned, similar to some giant FI in quartz. The demantoid garnet was investigated by X-ray computed tomography (CT) scanning to reveal its 3D interior morphology. Images were made with a Phoenix Nanotom S scanner using a resolution of 7.59 μm/voxel and an X-ray tube on nanofocus tension of 115 kV. The calculation of all the phases was computed by VGStudio software, and the volumes of the respective phases are the sums of voxels. The 3D tomography images show a unique fluid inclusion cavity (figure 2B) with a morphology like a negative crystal with polygonal outlines parallel to the faces of the host garnet crystal (figures 2C, D). All the criteria define a primary two-phase FI. The total volume of the garnet is 896.1 mm3, of which 6.2 vol.% is occupied by the FI cavity. The volume of the liquid phase is 52.16 mm3 and the volume of the vapor phase is 3.52 mm3, which corresponds to a liquid/vapor ratio of 6.75%.

Figure 2. 3-D tomography images of the demantoid and the giant fluid inclusion cavity. Top left: Morphology of the crystal. Top right: Tomographic section of the crystal showing the morphology of the fluid inclusion cavity. Bottom left: The internal view of the cavity showing the gas bubble. Bottom right: The cavity displays a negative crystal morphology with polygonal outlines parallel to the faces of the host garnet crystal, as well as the bubble phase (blue).

Figure 3. The micro-Raman spectra of the Antetezambato demantoid garnet in the
170–1200 cm–1 range (top) and the 2750–4000 cm–1 range (bottom).
The Raman spectrometry data show that the fluid is free of CO2, CH4, H2S, and N2: the FI is a primary two-phase aqueous FI (liquid + vapor). The salinity of the aqueous FI was determined by analyzing the Raman spectrum of H2O based on the weakening of the hydrogen bond by chloride. A deformation of the OH stretching vibration band of water appears in the range between 2900 and 3700 cm–1 (figure 3, bottom). Even if the cationic composition of the natural FI differs from pure sodium, the experimental approach yields the salinity of any inclusion accurately if NaCl is the main species (M.-C. Caumon et al., “Fused-silica capillary capsules (FSCCs) as reference synthetic aqueous fluid inclusions to determine chlorinity by Raman spectroscopy,” European Journal of Mineralogy, Vol. 25, No. 4, 2014, pp. 755–763). Under these conditions the calculated salinity for the demantoid garnet FI is about 8 wt.% equivalent NaCl.

The gem garnet mineralization of Antetezambato is described as a skarn-type deposit related to Upper Mesozoic to Cenozoic magmatism affecting the limestones of the Mesozoic Isalo Group (again, see Pezzotta et al., 2011). Similar demantoid-bearing skarns are described in the Ampasindava Peninsula at Ambohimirahavavy, 50 km west of Ambanja (G. Estrade et al., “REE and HFSE mineralization in peralkaline granites of the Ambohimirahavavy alkaline complex, Ampasindava peninsula, Madagascar,” Journal of African Earth Sciences, Vol. 94, 2014, pp. 141–155). The skarns of the Ambohimirahavavy alkaline granitioid complex are host to rare-metal mineralization. Peralkaline dykes intruded (at 24.2 ± 0.6 Ma) the limestone of the Isalo groups (G. Estrade et al., “Unusual evolution of silica-under- and -oversaturated alkaline rocks in the Cenozoic Ambohimirahavavy Complex (Madagascar): Mineralogical and geochemical evidence,” Lithos, Vol. 206–207, 2014, pp. 361–383) and developed a bi-metasomatic skarn. The metasomatic zone was formed at the contact with the calcareous rocks by calc-silicate rocks (exo-skarn zone) with diopside, garnet andradite (demantoid variety), calcite, apatite, phlogopite, fluorite, and wollastonite. At the contact of the granite (endo-skarn zone), the associated minerals are quartz, albite, aegirine-augite, and calcite (G. Estrade, “Le complexe cénozoïque alcalin d’Ambohimirahavavy à Madagascar: origine, évolution et minéralisations en métaux rares,” PhD thesis, Paul Sabatier University, Toulouse, France, 2014, 299 pp.) Exo-skarn paragenesis is also found as inclusions in the demantoid of Antetezambato, such as fluorine-(arsenic)-bearing apatite, fluorite, calcite, wollastonite, fluorine-bearing vesuvianite, diopside, calcite, and quartz (W. Barrois et al., “Caractéristiques minéralogique et chimique des grenats démantoides de Bagh Borj (Iran) et d’Antetezambato (Madagascar): conséquences géologiques. 2ème partie, Études minéralogique et chimique,” Revue de Gemmologie a.f.g., Vol. 183, 2013, pp. 10–15, in French).

Fluid inclusions were observed in all the minerals of the exo- and endo-skarns of the Ambohimirahavavy alkaline complex, but they were too small in the garnet for microthermometric studies. In quartz, calcite, and diopside, three types of primary aqueous FI, free of CO2, CH4, H2S, and N2, were characterized (see Estrade’s PhD thesis). The main FI type (liquid + vapor) consists of 20 to 40 vol.% vapor, and homogenizes to liquid between 255 and 375°C for quartz, and 350 to 370°C for diopside, with a wide range of salinity between 0.5 and 25 wt.% equivalent NaCl. There is also a vapor-rich (V) FI and a halite-bearing FI (liquid + vapor + halite). The giant liquid-rich FI (liquid + vapor) trapped by the demantoid of Antetezambato has a salinity of 8 wt.% equivalent NaCl that falls within the salinity range of the (liquid + vapor) FI type found for all the minerals from the Ambohimirahavavy skarn.

Such chemical and salinity similarities of the fluids between the two settings confirm that the Antetezambato deposit is associated with a skarn deposit linked to the intrusion of Oligocene alkaline magmatism. In the Ambohimirahavavy deposit, fluid inclusions in garnet are too small to be studied by microthermometry. The giant inclusion trapped in the demantoid from Antetezambato testifies to the presence of cavities favorable for fluid inclusion studies and proves that the parental fluid of demantoid garnet was aqueous.

Demantoid at Ambato peninsula is linked to the presence of alkaline magmas intruding limestones of the Isalo group. These garnets are Cr-free but contain Al (Barrois et al., 2013). The source of aluminum and iron is the alkaline magma (syenite, nepheline syenite, and alkaline granite), while calcium originated from the limestone. The fluorine and phosphorus-bearing inclusions trapped by the andradite from both occurrences were carried by the alkaline magma, which was rich in fluorine, phosphorus, and rare earth elements. In the future, primary skarn-type demantoid-bearing deposits in northwestern Madagascar at the contact between alkaline granite dykes and limestone from the Isalo Group should be prospected for this material. @chapter:12 @chapter:0 @chapter:12


# Publication Year: 2016
# Title: Decay Kinetics of Boron-Related Peak in IR Absorption of Natural Diamond
# Abstract: Figure 1. In response to UV excitation, the IR absorption spectra for a 1.01 ct Fancy gray,
nominally type IIa diamond shows a pronounced peak at 2800 cm–1, associated with
type IIb diamond and boron impurities. The intensity of the 2800 cm–1 peak decays over
several minutes. For the sake of clarity, not all collected IR absorption spectra are shown
here; the peak at 2850 cm–1 is unrelated to boron and is caused by hydrocarbon
contamination on the diamond surface.
Recently, gemologists at the National Gold & Diamond Testing Center in China found that the uncompensated boron peak at 2800 cm–1 in FTIR absorption could be induced by UV excitation and then subsequent decay, similar to the phosphorescence response often seen in type IIb diamonds (J. Li et al., “A diamond with a transient 2804 cm–1 absorption peak,” Journal of Gemmology, Vol. 35, 2016, pp. 248–252).

The Carlsbad laboratory recently received a nominally type IIa, 1.01 ct diamond with Fancy gray color. It was identified as natural and, uncharacteristically, showed a 500 nm band phosphorescence, which is typical for type IIb diamonds (S. Eaton-Magaña and R. Lu, “Phosphorescence of type IIb diamonds,” Diamond and Related Materials, Vol. 20, 2011, pp. 983–989). With UV excitation we recorded the transient 2800 cm–1 absorption (associated with uncompensated boron) observed in type IIb diamonds, and we monitored the peak’s decay (figure 1).

From the calculated area of the 2800 cm–1 absorption peak, we can determine the uncompensated boron (Bo) concentration (D. Fisher et al., “Brown colour in natural diamond and interaction between the brown related and other colour-inducing defects,” Journal of Physics: Condensed Matter, Vol. 21, 2009, 364213). Immediately after UV excitation, the diamond showed blue phosphorescence and the FTIR spectrum changed from a nominally type IIa diamond to a type IIb, with an uncompensated boron concentration of ~70 ppb (figure 2, left). An increase in the 2800 cm–1 peak upon UV excitation was previously recorded in some other type IIb diamonds as well and in a few other nominally type IIa diamonds examined by GIA, but those showed much lower values than this sample with UV excitation, with an initial increase in Bo of ~5 ppb or less. The decay of the 2800 cm–1 absorption band in the diamond studied here was well described by the non-exponential decay model 1/(1+kt), where t is the decay time and k is a constant. This equation fit the absorption decay data better than an exponential decay model or the hyperbolic decay model that describes type IIb diamond phosphorescence, 1/(1+kt)2 (K. Watanabe et al., “Phosphorescence in high-pressure synthetic diamond,” Diamond and Related Materials, Vol. 6, 1997, pp. 99–106).

Figure 2. Left: The uncompensated boron concentration for the IR absorption spectra in figure 1 were calculated and compared against several phosphorescence decay models. Right: The decay of the phosphorescence peak at 500 nm, also induced by UV excitation, was calculated and compared against the accepted model for phosphorescence. The DiamondView image shows the diamond’s blue phosphorescence.
Photoluminescence spectra were collected both with and without UV exposure using 488, 514, and 830 nm excitation. The only distinction observed between the two sets of spectra was the addition of a 3H peak (503.5 nm) when the diamond was exposed to UV radiation. The 3H peak is ascribed as an intrinsic defect containing interstitials and is often observed in PL spectra of type IIb diamonds.

Phosphorescence spectra were also recorded (figure 2, right). As expected based on prior research of diamond phosphorescence, the data did correspond well with the hyperbolic model. When boron impurities are present but are electrically compensated by other defects such as nitrogen, the 2800 cm–1 peak would not be detected and a nominally type IIa diamond would be recorded by IR absorption. However, UV excitation creates a charge transfer effect, temporarily uncompensating some of the boron so that the Bo concentration temporarily increases. This absorption decay of the 2800 cm–1 peak is most dramatic in nominally type IIa diamonds such as this sample, but has also been observed to a lesser extent in type IIb diamonds. There are several unanswered questions regarding the phosphorescence mechanism and decay kinetics in type IIb diamonds, and further study of this absorption decay will help address these issues. @chapter:22 @chapter:1 @chapter:22


# Publication Year: 2017
# Title: Quarterly Crystal: Barite in Fluorite
# Abstract: Figure 1. This 247.02 ct bright yellow fluorite partial crystal, which measures 40.04 mm tall, hosts two large concretions of bone-white barite. Photo by Kevin Schumacher.

Although gemologists deal primarily with fashioned gemstones, some crystal specimens are far too attractive as intact objects to be used as cutting rough. This is particularly true if they contain eye-visible inclusions like those seen in the 247.02 ct transparent yellow fluorite partial crystal shown in figure 1.

At 40.04 mm in its longest dimension, this specimen invites exploration of its inclusions, which were identified as barite using laser Raman microspectrometry. The larger of the two barites measures 7.0 mm in diameter and has a microscopically prominent rectangular purple spot on the apex of its dome (figure 2), which clearly stands out against the stark white background provided by the barite inclusion. Although the cause of the spot is unclear, the contrasting assemblage of colors adds to this specimen’s value as an aesthetic collector piece.

Figure 2. The largest of the two barite inclusions has a prominent purple spot on the top of its dome, which is easily seen against the white background provided by the inclusion. Photomicrograph by Nathan Renfro; field of view 13.71 mm. @chapter:15 @chapter:0 @chapter:15


# Publication Year: 2013
# Title: Multifacets: Style Yourself with Jewelry
# Abstract: Nathalie Cohn, creative director of Swarovski, shows the various ways jewelry can be worn to suit any occasion or setting: the workplace, cocktail hour, dining out, a night out, travel, or a wedding. Playful and irreverent, the book offers practical advice on adding touches of attitude, elegance, and personality to cultivate a highly personalized look. Each accessory’s color, texture, and shape can be used to achieve a “rich dialogue between jewelry, garment, and body.” Numerous images featuring Swarovski pieces offer strategy and inspiration for every woman who wears contemporary jewelry.

Reviewed by Stuart Overlin @chapter:20 @chapter:2 @chapter:20