Publish Year: - Title: Summer 2023 G&G Available Now Abstract: The summer issue of G&G is packed with interesting new content! In our three feature articles, read about a newly discovered treatment in spinel, a find of augite in Vietnam, and the origin of mammoth ivory’s brown color. In addition to these articles and our regular quarterly sections, we see the return of Colored Stones Unearthed and finish the issue with a spotlight on fire obsidian.
COLOR MODIFICATION OF SPINEL BY NICKEL DIFFUSION: A NEW TREATMENT
Dr. Michael Jollands and GIA researchers share their study of a new color treatment for natural spinel, which turns lightly colored stones into deeper blue and green hues. Their analysis of a set of faceted spinel submitted as “cobalt diffused” revealed that the gems were actually diffused with nickel. With this treatment likely to become more common in the gem market, the team also suggests criteria for identifying nickel diffusion in blue and green spinel.
GEM-QUALITY AUGITE FROM DONG NAI, VIETNAM
A team led by Le Ngoc Nang reports on a variety of gem-quality augite from Dong Nai, Vietnam. Characterized by intense dark brown or dark green colors when viewed in transmitted light, the augite is classified as magnesium-rich and has potential for use in jewelry and in carvings.
ORIGINS OF COLOR IN BROWN MAMMOTH IVORY
Mammoth ivory is most commonly found with a brown surface color. Zhaoying Huang and coauthors investigate the origin of this brown color by studying mammoth ivory samples’ spectroscopic and mineralogical characteristics, surface morphology, and chemical composition. They determine that formation of iron oxides, manganese oxides, manganese hydroxides, and iron sulfides on the ivory underground resulted in the brown surface color.
LAB NOTES
GIA’s global laboratory staff present their latest findings in the Lab Notes section, including yellow zoning in unusual natural pink diamonds, invisible markings in CVD laboratory-grown diamonds, and an exceptionally large South Sea cultured pearl.
MICRO-WORLD
The Micro-World section, dedicated to the inner world of gemstones, highlights thread-like serpentine inclusions in brown peridot, a globular iron stain and curved lines in yellow sapphire, an interesting metal sulfide inclusion in garnet, and more.
COLORED STONES UNEARTHED
Colored Stones Unearthed returns to examine gem minerals that form in metamorphic environments, such as jade, corundum, tanzanite, and tsavorite garnet. Studying these gems offers gemologists insight into the evolution of tectonic activity that led to their formation.
GEM NEWS INTERNATIONAL
GNI contributors cover a wide variety of topics, ranging from reports on several pearl species to a new treatment used to create phantom structure in opal. The section also includes a roundup of the spring 2023 auction highlights and recaps of the 2023 Sinkankas Symposium and the sustainability panels at the JCK show in Las Vegas.
IN THE SPOTLIGHT
Lastly, we spotlight fire obsidian, a rare volcanic glass found only in the Glass Buttes region of Oregon. Lapidary artist Tom Dodge shares his work revealing a vibrant spectrum of iridescent colors. @topic:2


Publish Year: 2023 Title: Sapphire from Montana’s Secondary Deposits, Colombian Emerald Morphology, the 2023 Tucson Shows, and More… Abstract: Welcome to the Spring 2023 issue of Gems & Gemology! A new volume year kicks off with our recap of the Tucson gem shows, where buyers, sellers, and industry professionals from all over the globe converge. And with two major feature articles, our regular sections, and the annual G&G Challenge, this issue is sure to captivate readers.
“The article also details the fascinating history of sapphire mining in these three Montana mining districts, which still hold substantial resources.”
In our lead article, Dr. Aaron Palke and coauthors present their study of the gemological characteristics of sapphire from Montana’s secondary deposits. Using Rock Creek, Missouri River, and Dry Cottonwood Creek samples in a variety of colors, the authors provide typical inclusion scenes and trace element chemistry fingerprints. The article also details the fascinating history of sapphire mining in these three Montana mining districts, which still hold substantial resources.
Next, Dr. Karl Schmetzer and Gérard Martayan investigate the less common morphological and growth phenomena of Colombian emerald samples to understand their growth and post-growth history. Based on their observation of 15 isolated emerald crystals and seven specimens in matrix using optical methods, they offer insight into the different patterns, with a goal of expanding the database of morphological features in Colombian emerald.
Our regular features provide informative snapshots, beginning with Lab Notes. Highlights from the section include a rare example of the purple collector gem anhydrite, a heart-shaped golden South Sea cultured pearl displaying natural shape and color, and the largest sample of synthetic rutile examined at GIA to date. Explore the inner landscapes of gemstones in our Micro-World section, where you’ll see rare cloud inclusions resembling a starry night in diamond, a macroscopic mineral inclusion cluster in a Pakistani aquamarine crystal, a three-phase inclusion in alexandrite, and more. Diamond Reflections returns in this issue, this time exploring plastic deformation in diamond. Our Gem News International section begins with nearly 30 pages covering the 2023 Tucson gem shows, ranging from the latest trends and market updates to noteworthy designs, followed by an opulent photo gallery packed with finds from the shows. The GNI regular features include various pearl discoveries from around the world and a new source of ruby from Liberia.
Finally, test your gemological knowledge of our 2022 feature articles in the annual G&G Challenge, and find out which articles received the Dr. Edward J. Gübelin Most Valuable Article Award.
We hope you enjoy the latest issue of Gems & Gemology! @topic:2


Publish Year: - Title: Spring 2023 G&G Available Now Abstract: A variety of topics awaits you in the Spring issue of G&G. With two feature articles, another installment of Diamond Reflections, our report on the 2023 Tucson shows, the annual G&G Challenge quiz, and more, there’s something for everyone inside.
GEMOLOGICAL CHARACTERIZATION OF MONTANA SAPPHIRE FROM THE SECONDARY DEPOSITS AT ROCK CREEK, MISSOURI RIVER, AND DRY COTTONWOOD CREEK
Dr. Aaron Palke and coauthors share their in-depth study of Montana sapphire from secondary deposits at Rock Creek, Missouri River, and Dry Cottonwood Creek. After detailing the fascinating history of sapphire mining and the geology of these three Montana mining districts, the authors cover the gemological characteristics of secondary Montana sapphire, including a comparison to the characteristics of sapphires from Tanzania. Finally, the article chronicles the heat treatment process of five Montana sapphire samples.
MORPHOLOGY OF COLOMBIAN EMERALD: SOME LESS COMMON CASES AND THEIR GROWTH AND DISSOLUTION HISTORY
Dr. Karl Schmetzer and Gérard Martayan investigate the morphological features in Colombian emerald to understand their growth and post-growth history. After studying a collection of 15 isolated emerald crystals and seven specimens in matrix using optical methods, the authors offer insight into the different patterns, including possible relationships to trapiche emeralds and those exhibiting the gota de aceite effect.
LAB NOTES
GIA’s global laboratory staff present their latest findings in the Lab Notes section, including a Libyan Desert glass bangle bracelet, a collection of pearls treated to look antique, and the largest faceted synthetic rutile examined at GIA to date.
MICRO-WORLD
The Micro-World section, dedicated to the inner world of gemstones, highlights a three-phase inclusion in alexandrite, a garnet inclusion resembling a flying insect in diamond, a series of negative crystals arranged in an arrow-like pattern in sapphire, and more.
DIAMOND REFLECTIONS
Diamond Reflections returns in this issue, providing a look at plastic deformation, one of the most prevalent features in natural diamond.
GEM NEWS INTERNATIONAL
Finally, the Gem News International section starts with our coverage of the 2023 Tucson gem shows, including the latest trends, market and mining updates, as well as handcrafted designs and unique specimens from all over the world. The GNI section continues with more noteworthy content, including reports of pearls from the UAE, Bahrain, and Chile and a color study of fancy sapphire from Greenland.
The Spring issue also contains the 2023 Gems & Gemology Challenge quiz. Score 75% or better and you’ll receive a certificate of completion (PDF file); earn a perfect score and your name will be listed in the Fall 2023 issue. Online entries for the Challenge must be submitted by Friday, September 1, 2023. @topic:2


Publish Year: 2023 Title: Quarterly Crystal: Columbite(?) in Beryl Abstract: Figure 1. Measuring 26.36 mm in length and weighing 56.00 ct, this Pakistani aquamarine crystal is host to an eye-visible 7.20 mm mineral inclusion cluster. Photo by Annie Haynes.
Those in the gem and mineral community can appreciate the near-perfection of a beautifully crystallized mineral specimen or a well-cut gemstone. But these surfaces are only the exterior, covering a complex, multilayered story within. These internal contents often remain unknown unless we choose to explore below the surface. Somewhat like trees and their rings, minerals and gems form as concentric, typically crystallized layers, recording the developmental details within each layer through changes in temperature, pressure, and chemistry. While some of these growth details are submicroscopic and remain hidden during microscopic observation, other features such as mineral inclusions and encapsulated fluids are waiting to be discovered. In a very real sense, inclusions and their developmental sequencing in their host gems and minerals are descriptions of mineralogical genetics.
Researchers focused specifically on inclusions usually cannot outbid serious gem and mineral collectors for crystals and fashioned gems with interesting internal targets. As a result, many such “gems” end up in private collections, and their inclusions are rarely, if ever, fully documented. This is a tremendous missed opportunity, because inclusions contain geological information that tells a story about themselves and their host.
For this issue’s Quarterly Crystal, we recently had the opportunity to document a well-formed gem-quality, transparent, very light greenish blue terminated hexagonal crystal of aquamarine, with a small amount of light brown matrix at the base and a clearly visible inclusion cluster at the near center (figure 1). The aquamarine was obtained from Muntazir Mehdi of Shad Fine Minerals International in Gilgit-Baltistan, Pakistan. The geographic source was reportedly the Kharguluk mine in Baltistan Province.

Figure 2. None of the analytical techniques at our disposal were able to conclusively identify the mineral making up the 7.20 mm inclusion cluster. The distinctive morphology shown by these inclusions strongly suggests that the cluster is composed of columbite-(Mn) crystals. Photomicrograph by Nathan Renfro; field of view 10.28 mm.
At 56.00 ct with corresponding measurements of 26.36 × 16.09 × 15.02 mm, this aquamarine played host to an easily eye-visible tight cluster of randomly arranged dark reddish brown to black bladed crystals (figure 2) that resembled the mineral columbite-(Mn), Mn2+Nb2O6, as shown by E.J. Gübelin and J.I. Koivula (Photoatlas of Inclusions in Gemstones, Volume 2, Opinio Verlag, Basel, Switzerland, 2005, pp. 263, 319).
Micro-Raman has significantly reduced the time required to instrumentally identify many inclusions. Some inclusion identifications that once took hours can now be made in a matter of minutes using this technique. The Raman instrument can also analyze some subsurface inclusions at depths of more than a millimeter in certain favorable instances, which means inclusions do not need to be exposed to the surface.
After several Raman attempts from different directions, we realized that destructive analysis would be needed to clearly identify the inclusion cluster deep within this stone. Due to the value of this inclusion specimen, we opted to forgo destructive analysis and keep the beryl crystal intact for future gemological exploration. @topic:1


Publish Year: 2023 Title: Tucson 2023 Overview Abstract: Figure 1. This ring from Graff features a 3.95 ct pink sapphire and 7.5 carats of diamond in a spiral design. Photo by Robert Weldon; courtesy of Jewelerette Co.
This year’s Tucson shows were well attended, and many vendors were relieved by the strong sales. In fact, the only “complaint” from vendors this year was that for many it was too busy to take even a short break away from their booths. Some vendors reported selling less than in 2022, but still more than in pre-COVID years.
Supply chain issues resulting from lack of output during the pandemic are still being felt. For many sellers demand often exceeded supply, especially for fine-quality colored stones, and prices are increasing to reflect that. With this increase expected to continue, the heavy booth traffic could be due to consumers buying as much as possible at these price points. This corresponds with comments from Nathan Renfro on the GIA show services laboratory, which received a near-record number of submissions this year. As for the trends in materials submitted to the lab, he indicated a typical mix of the major stones: mainly ruby, sapphire, emerald, Paraíba tourmaline, and alexandrite.

Figure 2. Left: “Edison” pearls were available in large sizes and attractive colors. Photo by Si Athena Chen; courtesy of A&B Jewelry. Right: A strand of “Edison” pearls of various colors, in sizes from 14 to 16 mm. Photo by Mimi Travis; courtesy of Yen’s Jewelry & Accessories.

Figure 3. This pin features a 63.92 ct Ethiopian opal with 23.85 carats of conch pearl, 5.88 carats of natural pearl, and 15.85 carats of diamond, set in platinum. Photo by Robert Weldon; courtesy of Pioneer Gems of New York.
At the AGTA GemFair and Gem & Jewelry Exchange (GJX) shows, sapphire, large freshwater pearls from China, and Ethiopian opal were among the eye-catching gems. Sapphire was once again a top seller, with blue and untreated colors doing especially well. Many fancy-color sapphires, including ones in saturated hues such as magenta, were available (Pantone’s Color of the Year for 2023 is Viva Magenta) (figure 1). There were multiple sellers of akoya, Tahitian, and “Edison” pearls in both venues. Most notably, “Edison” pearls were available in much larger sizes and with more saturated colors than in years past (figure 2). Non-nacreous pearls were also featured more prominently. Ethiopian opal, first introduced in Tucson in 2009, was very popular this year. It has climbed from a novelty to a gemstone found in top designer luxury jewels, such as the Zoltan David necklace shown on the cover of this issue and the pin featuring both Ethiopian opal and conch pearls in figure 3. Tourmaline from newly discovered pockets in San Diego County’s Pala District was also on display.

Figure 4. Earrings featuring diamond slices and rose-cut rubies. Photo by Mimi Travis.

Figure 5. “Salt and pepper” diamonds containing eye-visible inclusions. Photo by Jennifer Stone-Sundberg; courtesy of Misfit Diamonds.

Figure 6. An unusual 6.95 ct cushion-cut bicolor alexandrite from Madagascar displaying a color change from yellowish green and reddish brown in daylight (left) to yellowish orange and orangy brown in incandescent illumination (right). Photos by Robert Weldon; courtesy of Bryan Lichtenstein, 3090 Gems, LLC.
The demand for one-of-a-kind gems was apparent in all aspects—cut, color, and even inclusions. Nontraditional cuts such as slices, fantasy cuts, rose cuts, kites, and tablets were readily found in gems ranging from rutilated quartz to diamond (figure 4). Beyond nonstandard cuts, stones with obvious inclusions were very popular. The appeal of these stones centers on their uniqueness. “Salt and pepper” diamonds with multiple eye-visible white, gray, and black inclusions were available loose (figure 5) and in jewelry items throughout the shows. Similarly, nontraditional colors for particular varieties, including color-change stones, pastel colors (such as “mint” tourmaline), teal, and bicolor stones, were trending (figure 6). Strong demand for these nontraditional or one-of-a-kind stones comes from small-scale individual designers with the ability to promote to a wide audience via social media.
In 2020, we reported on the first Ethical Gem Fair in Tucson. This year, suppliers at the fair were pleasantly surprised by the number of large jewelry manufacturers who attended for the first time. The trend toward responsible sourcing, traceability, transparency in practices, and social awareness, which has long been a key differentiator for some jewelers, is clearly becoming more mainstream as customers increasingly demand to know more about the origin and impact of the stones they are purchasing. This year, jewelers at AGTA and GJX also emphasized the importance of providing an environmentally conscious product and the increasing demand from clients for full chain-of-custody information on stones. Similarly, many small-scale designers and buyers were seeking out gems mined in the United States, such as Montana sapphire, Oregon sunstone, and amethyst from the Four Peaks mine in Arizona. They noted high demand for these gems, which seem to satisfy consumer sustainability concerns. In many cases, the younger generation of jewelers has brought a focus on ethical and environmentally sound practices to multigenerational businesses.
We hope you enjoy our coverage of the 2023 Tucson gem shows, where you’ll find striking pieces we saw, the latest trends, mining updates, and more.
The following contributed to this report: Lisa Neely, Mimi Travis, Nathan Renfro, Albert Salvato, and Wim Vertriest.

View Gallery

Photo Highlights from the 2023 Tucson Shows @topic:11


Publish Year: 2023 Title: Rare Double Pseudomorph Ikaite-Calcite-Opal Abstract: Figure 1. The Heart of Australia, a 3,510 ct double pseudomorph ikaite-calcite-opal gem specimen, is considered one of the finest ever unearthed. Courtesy of Graeme Dowton.
At the Pueblo Gem & Mineral Show, Graeme Dowton of Red Earth Opal (White Cliffs, Australia) exhibited rare double pseudomorph ikaite-calcite-opal gem specimens mined from the Naatji Nest mine at White Cliffs in New South Wales, Australia. Ikaite was initially substituted with calcite and then opalized, therefore making these double pseudomorph opals. Also called “pineapple opal” in the market due to the form of their clusters, they are found exclusively in White Cliffs and typically occur within weathering-bleached siltstones and claystones. According to Dowton, no other type of gem-quality opal was found in the same layer where the pineapple opals were mined. During mining, it was noticed that two opals had formed within a few feet of each other but with distinctly different coloration: One displayed a rich spectrum of play-of-color, while the other showed almost no coloration. The 3,510 ct Heart of Australia (figure 1) shows rich play-of-color and is considered one of the finest specimens of this type ever unearthed. In some of Dowton’s samples, the precursor calcite was not fully substituted by silica gel, and white calcite crystals can be observed (figure 2).

Figure 2. The intergrowth of opal and its precursor calcite in pineapple opal. This specimen is 12 × 10 × 8 cm and weighs 690 g. Photo by Si Athena Chen; courtesy of Graeme Dowton.
Ikaite, CaCO3•6H2O, is a rare and metastable hydrated carbonate in sedimentary rocks that has only been identified in environments ranging from –2° to 7°C in nature (M.L. Vickers et al., “The ikaite to calcite transformation: Implications for paleoclimate studies,” Geochimica et Cosmochimica Acta, Vol. 334, 2022, pp. 201–216). The occurrence of ikaite suggests a period of very cold to near-freezing paleoclimate conditions in White Cliffs. At ambient temperatures (10°–30°C), ikaite transforms to more stable carbonate polymorphs such as calcite, aragonite, and/or vaterite. The ikaite and its following pseudomorphs act as paleothermometers (D. Shearman and A. Smith, “Ikaite, the parent mineral of jarrowite-type pseudomorphs,” Proceedings of the Geologists Association, Vol. 96, No. 4, 1985, pp. 305–314). When the host sedimentary rocks were weathered, they released silica into groundwater. This silica-bearing groundwater contacted with calcite, which gradually dissolved and reprecipitated to opal over time (B. Pewkliang et al., “The formation of precious opal: Clues from the opalization of bone,” Canadian Mineralogist, Vol. 46, No. 1, 2008, pp. 139–149). However, the detailed formation mechanism of ikaite-calcite-opal in White Cliffs requires future investigation. @topic:13


Publish Year: 2022 Title: Custom Knives by Loren Feldman Abstract: Figure 1. Loren Feldman holds a piece of gem dinosaur bone, displaying the variety of colors and textures he can choose for his knives. Photo by Robert Weldon; courtesy of Loren Feldman.
Some of the most interesting discoveries in Tucson came courtesy of Loren Feldman (Feldman Custom Knives, Gold Canyon, Arizona). His knives are works of art constructed from some of the rarest materials on Earth—and other planets. A visit to Feldman’s booth is a fascinating walk through history that reveals geological treasures such as Tyrannosaurus rex bones, woolly mammoth tusks, and meteorites that fell to the earth millions of years ago.
Remarkably, Feldman has only been making knives for seven years. He describes his introduction to the craft and training as pure luck. Collecting rocks and minerals since he was a young boy, Feldman impressed custom knife maker Robert Stratton with his enthusiasm at the 22nd Street show in Tucson. After a fourth visit to the booth, Stratton generously offered to teach Feldman everything he knew about the craft. At the end of the training, he allocated part of his Tucson booth space to help Feldman get his start in the business. Feldman said that after his apprenticeship, “it took me about two years full-time to consider my work what I considered good. It took me about three years to pay all my bills. And seven years later, it’s the happiest I’ve ever been as far as a profession.”
Feldman’s knife handles are crafted from minerals, gems, and fossilized dinosaur bone. One of his favorites is a knife made of gem dinosaur bone from nine different dinosaurs (shown on the cover of this issue). He explained that only 1/20 of 1% of all dinosaur bone turns into gem, describing it as a miracle of nature because it is only created under very specific conditions. During this process, the dinosaur bone undergoes a transformation that leaves the bone with a beautiful pattern of color and texture (figure 1). Of all the materials he uses, he gets the most excited about gem dinosaur bone because it’s so scarce and highly coveted (figure 2). Feldman also makes his handles from rare gems and minerals from all over the world, such as charoite from Siberia, Ammolite from Alberta, green jade from British Columbia, black jade from Western Australia, dumortierite from Mozambique, lapis lazuli from Afghanistan, labradorite from Madagascar, and agate from Northern Mexico.

Figure 2. Feldman studies a piece of gem dinosaur bone he cut, contemplating how to incorporate it in the knife handle. Photo by Robert Weldon; courtesy of Loren Feldman.
Equally impressive are Feldman’s blades. Made of fine American Damascus steel, the blades are one of three types: carbon, stainless steel, or mosaic. Feldman also crafts blades from iron meteorites that fell to the earth millions of years ago (figure 3). Feldman noted that while rare and expensive, meteorite has been used to make knives throughout history, adding that at least one meteorite blade was found in King Tut’s tomb.

Figure 3. A finished six-inch knife featuring a meteorite blade and gem dinosaur bone handle. Photo by Robert Weldon; courtesy of Loren Feldman.
Feldman purchases some of the material he uses but also does his own exploration and digging. Each summer, he visits a friend’s ranch in Montana to dig for dinosaur bone, and any bone recovered is sent to a lab for identification. He recently found enough T. rex bone to make a knife. Feldman noted that he’s never seen another knife maker incorporate T. rex bone.
Each knife comes with a sheath made of premium leather or exotic skin such as alligator, snake, or elephant—“all legally obtained,” Feldman said. About half of Feldman’s customers also purchase stands, which are crafted with the same rare materials, including dinosaur bone, woolly mammoth tusk, and fine gemstones, and are often chosen to coordinate with the materials in the knife.
When asked what he enjoys most about his business, Feldman revealed that his favorite part is attending the shows and talking with customers. “Doing these events and meeting the collectors, the hunters, the scientists, museum curators, and the professors. I love learning more about the products I sell. Just about everything that I share with my customers, I learned here at this very show.”
For Feldman, business is better than ever. The pandemic has increased the demand for his handmade creations. He explained that customers have been treating themselves during a time when they’ve been deprived of so much. His clientele, which includes collectors, investors, ranchers, hunters, and culinary artists, has kept him busy for the past two years. @topic:6


Publish Year: 2009 Title: Hackmanite/Sodalite from Myanmar and Afghanistan Abstract: In recent years, significant amounts of gem-quality sodalite/hackmanite—some unusually transparent—have been produced from the Mogok region of Myanmar and Badakhshan Province in Afghanistan. Samples from both countries varied in color, transparency, UV fluorescence/phosphorescence, tenebrescence, and UV-Vis-NIR spectra. The Burmese material was generally more included and showed weaker fluorescence and phosphorescence than the Afghan samples. EDXRF spectroscopy revealed traces of sulfur in all samples. The tenebrescence of many of the stones from both localities was strong enough for classification as hackmanite. @topic:1


Publish Year: 2021 Title: New CVD Material Submitted for Analysis Abstract: Figure 1. These 10 CVD-grown diamonds submitted to the New York laboratory were fairly large (2.24 ct to 5.90 ct) with high color grades (D to F) and excellent clarity (VVS2 to VS1). Photo by Sood Oil (Judy) Chia.
Since the introduction of its new digital Laboratory-Grown Diamond service, GIA has recently seen a vast increase in the number of diamonds grown by chemical vapor deposition (CVD). These are often large and of exceptional clarity. The New York laboratory recently examined a batch of 10 large, high-quality CVD-grown diamonds from a single client, Shanghai Zhengshi Technology. The diamonds ranged from 2.24 ct to 5.90 ct and came in a variety of fancy shapes, as well as the standard round brilliant cut. All of them had high color grades, ranging from D to F, and excellent clarity, with grades between VVS2 and VS1 (figure 1).

Figure 2. PL spectrum showing the 596/597 nm doublet observed in an as-grown CVD diamond.
The diamonds were all identified as type IIa using Fourier-transform infrared (FTIR) spectroscopy, with the 3123 cm–1 peak that is attributed to most as-grown CVD synthetics and the 3017 cm–1 peak that can be found in treated CVD synthetics both notably absent from their spectra. PL spectroscopy using a 514 nm laser revealed SiV (737 nm), NV– (637 nm), and NV0 (575 nm) centers in all of the diamonds. Also observed was the 596/597 nm doublet, a feature commonly seen in as-grown CVD diamond indicating no treatment was applied (figure 2) (S. Odake, “Melee diamonds: Metal defects and treated color,” Fall 2018 G&G, p. 304).

Figure 3. Each CVD-grown diamond showed a strong birefringence pattern displaying many interference colors. The pattern is not disrupted by the presence of pinpoint inclusions in the diamonds. Photomicrographs by A’Dhi Lall and Elina Myagkaya. Field of view 19.27 mm (left) and 1.26 mm (right).

Figure 4. DiamondView imaging revealed homogenous, unbroken dislocations without the distinct banding that is common in CVD-grown diamonds. Images by Elina Myagkaya.
The diamonds showed strong birefringence when viewed under cross-polarized light, exhibiting both low and high interference colors (figure 3). DiamondView imaging revealed mostly blue, purple, or pink fluorescence, with blue-violet dislocations that were clearly observed in all of the diamonds tested. More notable was the absence of the striations commonly seen in CVD diamonds, which indicate start-stop growth and changing growth conditions (figure 4). The absence of striations implies that these diamonds might have been grown in one continuous step—the fact that the dislocations appear to be homogenous and uninterrupted supports this theory.
This group of lab-grown diamonds possessed high clarity and high color for as-grown material, demonstrating the potential for large lab-grown diamonds to make large inroads in the gem diamond market. With continuing improvements to growth technology, lab-grown diamond identification faces many challenges. While large batches of CVD synthetics from different manufacturers have been documented by GIA in the past (e.g., W. Wang et al., “CVD synthetic diamonds from Gemesis Corp.,” Summer 2012 G&G, pp. 80–97), this set offers insight into potential new CVD growth conditions for CVD synthetic diamonds. @topic:4


Publish Year: 2015 Title: Update on Rock Creek Sapphire Deposit Abstract: Figure 1. Excavators and a washing plant on Gem Mountain process gravel for sapphire recovery. Photo by Warren Boyd.

Recently, Montana-based Potentate Mining LLC secured approximately 3,000 acres of sapphire-bearing ground covering the famous Rock Creek sapphire district near Philipsburg, Montana. Since the discovery of these sapphire deposits in the 1890s, this is the first time that one company has consolidated such a large land position, encompassing the old alluvial sites as well as the area on the hills in between these old workings (figure 1). Potentate has assembled a team of highly experienced placer miners, geologists, mining engineers, and heavy equipment operators to recover and process the sapphires from this mine.

The Rock Creek district sapphire deposits occur in debris flow, colluvium, and secondary alluvial deposits (figure 2). Although the bedrock for these deposits has not yet been defined, Potentate plans further geological mapping and geophysical surveys in the near future to uncover these sources.

Figure 2. A trench on Gem Mountain showing the sapphire-rich colluvium on the hilltops between the previously worked gulches. Photo by Keith Barron.
To date, the rough sapphires recovered from the bulk sampling pits range in size from 0.25 ct to over 20 ct. Approximately 15% of this rough occurs naturally in marketable colors, including pink, orange, orange-pink, lavender, golden yellow, blue-green and green, and fine blue (figure 3). A substantial percentage of the remaining rough responds very well to heat treatment technologies that improve clarity and turn greenish and grayish rough to desirable colors such as blue, orange, yellow, pink, and parti-color.

Figure 3. A selected assortment of unheated rough sapphires from the Rock Creek deposit weighing from 0.50 to 17 ct. Photo by Warren Boyd.
The high-grade concentration of the sapphires recovered from the various test pits, and the substantial inferred rough sapphire resource on Gem Mountain, indicate that Potentate would be able to provide a long-term, consistent supply of sapphire rough to the global market (figure 4). Potentate would be the only large-volume source for the Rock Creek sapphires. The company is developing a marketing strategy that would provide sustainable supply chain guarantees to their clients. These clients including wholesale gemstone cutters, polishers, and fine jewelry retailers would in turn be able to provide guarantees of origin and the presence (or absence) of any heat treatment to their consumers.

Figure 4. A selection of natural and heat-treated Rock Creek sapphire ranging from 0.50 to 4.70 ct. Photo by Jeff Scovil. @topic:2


Publish Year: 2021 Title: Rock Creek Sapphire Mining and Marketing Update Abstract: Figure 1. The newly equipped water clarifier at the West Fork property can nearly fully recycle the water used for mining. Courtesy of Potentate Mining

              Sapphires were discovered in Montana on the West Fork of Rock Creek in 1892. The shiny pebbles were later identified as sapphire and featured at the Paris Exposition in 1900. Four deposits, one primary and three secondary, were discovered and developed across the western portion of the state. Among them, the secondary deposit at Rock Creek has always been the richest and the most productive. It is estimated that this deposit produced about 65.8 tons of rough sapphire until 2014, which is about 90% of the total sapphire production of all four deposits.

Since 2011, Potentate Mining has been gradually developing and expanding its sapphire mining concession in the Rock Creek area through a series of land purchases. With the latest deal done in 2020, the company now possesses more than 3,500 acres of private property over the sapphire-bearing land.

In addition to the expansion, in 2019, the washing plant moved from Eureka Gulch to a new location at the West Fork property, where mining is done on the top of the hill (T. Hsu et al., “Big Sky Country sapphire: Visiting Montana’s alluvial deposits,” Summer 2017 G&G, pp. 215–227). This new washing plant includes a water clarifier that, although not required by state mining regulations, can recycle nearly 80–90% of the water used for mining (figure 1). Before the wastewater reaches the clarifier, it goes through a centrifugal concentrator to recover fine gold and very small sapphires (figure 2). This washing plant is also extremely close to the mining site, which dramatically increases the efficiency of ore processing.

Figure 2. Left: Potentate Mining marketing director Warren Boyd (on the right), mine geologist and manager John Rae (in the back), and a client gather around the centrifugal concentrator. Right: The concentrator extracts fine gold and very small sapphire crystals from the water coming out of the jig before it enters the clarifier. Courtesy of Potentate Mining.
Potentate Mining sells rough and faceted sapphire at the Tucson and JCK shows to retailers and jewelry designers. Since 2016, it also offers natural, heat-treated rough sapphire by lots to clients in North America, India, Sri Lanka, and Thailand. Most of these clients are cutting operations. The COVID-19 pandemic reduced the number of staff working onsite at the mine in 2020, but the production was not dramatically affected. Due to travel restrictions, stone viewing became extremely difficult. According to marketing director Warren Boyd, lots have been shipped to clients since the start of the pandemic. While viewing ahead of receiving lots was impossible, the company expected and has accommodated a certain amount of returns from clients. With Potentate adapting to the unexpected, 2020 sales were about the same as the year before. @topic:2


Publish Year: - Title: Winter 2022 G&G Available Now Abstract: The Winter issue features three studies on identifying treatments in colored gemstones—ruby, feldspar, and turquoise—and introduces us to an inspirational artist and pioneer in the jewelry industry. In addition to the four feature articles and our quarterly sections, we see the return of Colored Stones Unearthed.
A CANARY IN THE RUBY MINE: LOW-TEMPERATURE HEAT TREATMENT EXPERIMENTS ON BURMESE RUBY
E. Billie Hughes and Wim Vertriest conduct low-temperature heating experiments on Burmese ruby. The appearance of inclusions at each heating step, coupled with spectroscopic analysis, provides evidence of this treatment. Particular solid inclusions proved sensitive to low-temperature heating.
FLUORESCENCE CHARACTERISTICS OF TWO COPPER-DIFFUSED PLAGIOCLASE FELDSPARS: LABRADORITE AND ANDESINE
For this study, Qingchao Zhou and fellow researchers treated colorless labradorite and light yellow andesine with copper diffusion to mimic the color of natural labradorite sunstone. They discovered that fluorescence emission characteristics under 320 nm excitation can potentially help identify copper diffusion treatment in a material that has been a subject of controversy for decades.
COMPOSITION AND SPECTRAL CHARACTERISTICS OF PORCELAIN-TREATED TURQUOISE
A team led by Liying Huang uses a combination of low specific gravity, strong luster, high silica content, and surface features to effectively identify the novel “porcelain” treatment technique. This treatment method improves the luster and color of low- to medium-quality turquoise to meet the demand for scarcer high-quality natural turquoise in the Chinese market.
NEVER STOP INNOVATING: GEM ARTIST CHI HUYNH
Tao Hsu and coauthors visit Chi Huynh, founder and owner of Galatea: Jewelry by Artist, who shares his experiences and passion for jewelry-making innovations. Carved pearls, gem bead cultured pearls, and two-way shape-memory jewelry are but a few of the groundbreaking jewelry design concepts he employs in his finished pieces.
LAB NOTES
GIA’s global laboratory staff present their latest findings in the Lab Notes section, including a unique chrysoberyl displaying four-rayed asterism, the largest cat’s-eye emerald examined by GIA to date, and the identification of two non-nacreous bead cultured pearls from Pinctada margaritifera.
MICRO-WORLD
The Micro-World section, dedicated to the inner world of gemstones, features unusual “horsetail” and columnar inclusions in demantoid, a bluish green omphacite crystal in colored diamond, and aegirine inclusions in poudretteite from a new deposit in Mogok.
COLORED STONES UNEARTHED
Colored Stones Unearthed returns to examine gem minerals that form in magmatic environments, such as diamond, garnet, spinel, and corundum. Through these gems, gemologists gain insights into the generation of magmas within the earth, their transport to the surface, and modes of volcanic processes after eruption.
GEM NEWS INTERNATIONAL
Finally, GNI’s global contributors report on a variety of topics, including an extremely rare hellandite inclusion in ruby from Mogok; the identification of natural, reconstructed, and imitation Burmese root amber; and a roundup of the fall 2022 auction highlights, which had several surprising twists. @topic:2


Publish Year: 2018 Title: Discovery of Color-Change Chrome Grossular Garnets from Ethiopia Abstract: Figure 1. Left: Three rough garnets (left to right, stones 2, 3, and 4) and one faceted garnet photographed in an LED light source with 6000K color temperature (a daylight-equivalent light simulator). Right: The same stones photographed in an LED light source with 3100K color temperature (an incandescent light simulator). The 2.705 ct faceted stone measures 8.08 × 7.18 × 5.49 mm. Photos by Kevin Schumacher.
Ethiopia has become a significant producer of opal, sapphire, and emerald in recent years. In addition, reports of gem-quality green garnets have started to emerge (B. Williams et al., “Tsavorite reportedly from Ethiopia,” Journal of Gemmology, Vol. 35, No. 8, 2017, pp. 702–704).
Todd Wacks (Tucson Todd’s Gems, Tucson, Arizona, and Vista, California) recently submitted three rough and one faceted garnet (figure 1, stones 1, 2, 3, and 4) to GIA in Carlsbad for scientific examination. He purchased the garnets from Inna Gem, which reported that the garnet mine is located near the town of Wbi and the new Dubuluk emerald deposit (Spring 2017 GNI, pp. 114–116). The stones showed obvious color change from yellow-green under daylight-equivalent lighting to orange-brown under incandescent illumination. This is similar to the color-change behavior reported for some color-change garnets from Sri Lanka (Spring 2017 GNI, pp. 137–138).
Standard gemological testing revealed a refractive index (RI) of 1.740 on the faceted stone. Hydrostatic specific gravity (SG) of all garnets in this study ranged from 3.62 to 3.68. Fluorescence was inert to long-wave and short-wave UV light. Rotating the stones 360° between a pair of crossed polarizing filters revealed an anomalous double refraction. Using a handheld spectroscope, faint absorption bands at 480–490 and 570–590 nm were observed. Microscopic examination showed fingerprints composed of two-phase inclusions, iron-stained and cloudy fractures, long thin etch channels, unidentified transparent crystals, and zoned greenish brownish yellow areas. These properties are consistent with grossular (grossular-andradite) garnets (I. Adamo et al., “Tsavorite and other grossulars from Itrafo, Madagascar,” Fall 2012 G&G, pp. 178–187; M.L. Johnson et al., “Gem-quality grossular-andradite: A new garnet from Mali,” Fall 1995 G&G, pp. 152–166).
Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) analyses were performed to obtain the chemical composition of these garnets using a Thermo Fisher iCAP Qc ICP-MS coupled with an ESL NWR213 nm laser ablation unit. USGS glass standards GSD-1G and GSE-1G and NIST glass standard 610 were used as external standards. 29Si was used as an internal standard. The analyses were performed in the same region where spectroscopic data was collected for stones 3, 4 (Ethiopian garnets), 5 (non-Ethiopian tsavorite), and 6 (non-Ethiopian demantoid) (see supplementary table S1).

Figure 2. The calculated visible absorption spectra (corrected for reflection loss) of garnets 3, 4, 5, and 6 with various path lengths. Transmission window A is centered at 545 nm. Transmission window B is between 620 and 650 nm; transmission window C is centered at 520 nm. In Ethiopian grossular stones 3 and 4, the absorption bands at 431 and 599 nm are caused by Cr3+. In stone 5 (non-Ethiopian tsavorite) the absorption bands at 428 and 611 nm are caused by V3+. In stone 6 (non-Ethiopian demantoid) the absorption bands at 431 and 627 nm are caused by Cr3+ (Adamo et al., 2009). The human eye is not color sensitive above 650 nm or below 420 nm wavelength (gray color zoning in the graph). The transmission in these ranges cannot contribute to the color seen. Please note that the y-axis units are in true absorbance and not absorbance coefficients.
The Ethiopian garnets are predominantly composed of 87.24–91.60% grossular, 6.03–8.19% andradite, 1.04–2.80% spessartine, 1.29–0.55% uvarovite, 0.71–0.82% pyrope, and 0.03–0.05% goldmanite (again, see stones 1–4 at the link provided above). The dominant chromophore is Cr3+ at about 0.19–0.43 wt.%, with an almost negligible contribution from V3+. This contrasts significantly with most tsavorite grossular garnets, whose color is dominantly derived from V3+ with a lesser contribution from Cr3+ (Adamo et al., 2012).

Figure 3. The color panels of four garnets (stones 3, 4, 5, and 6) under CIE A (incandescent) and CIE D65 (daylight-equivalent) illumination are quantitatively reproduced. The garnets’ colors are shown at different light path lengths (defined by stone thickness). For each sample, the top and bottom rows represent the color under incandescent light (A) and daylight-equivalent light (D65), respectively. For calculation methods, please see Sun et al. (2017).
UV-Vis-NIR spectra (figure 2) were collected and corrected for reflection loss. These spectra were then used to quantitatively calculate the color of the garnets at a wide range of path lengths and under different lighting conditions. In addition to two of the Ethiopian grossular garnets, UV-Vis spectra were also collected on the non-Ethiopian tsavorite (stone 5) and the non-Ethiopian demantoid (stone 6) for comparison. The chemistry of stones 5 and 6 is also reported; see the supplementary table S1.

The calculated color panels of stones 3–6 under daylight-equivalent lighting (CIE D65 illumination) and incandescent light (CIE A illumination) are shown in figure 3, which shows the possible colors these four garnets would exhibit with different path lengths (defined by stone thickness) and the approximate corresponding carat weight of a well-proportioned round brilliant (for details of this calculation, see Z. Sun et al., “Vanadium- and chromium-bearing pink pyrope garnet: Characterization and quantitative colorimetric analysis,” Winter 2015 G&G, pp. 348–369). Ethiopian grossular stone 4 showed a stronger color change and a higher chromium component than Ethiopian grossular stone 3. Stone 6 showed a more yellowish green than stone 5 due to the demantoid’s higher Fe component, which absorbs more blue light than in tsavorite (again, see figure 2).

Figure 4. In the CIELAB 1976 color circle, the color of stone 4 changes from yellow-green under CIE D65 illumination to yellow-orange under CIE A illumination, with a hue angle difference of 16.68˚ and a chroma difference of 7.40. The color of stone 3 changes from yellow-green under CIE D65 illumination to yellow-orange under CIE A illumination, with a hue angle difference of 15.94˚ and a chroma difference of 3.74. Stone 5 (tsavorite) has no color change in D65 and A visually. The hue angle difference is 0.48˚, and the chroma difference is 21.73. Stone 6 (demantoid) has no color change in D65 and A visually. The hue angle difference is 1.63˚, and the chroma difference is 20.54.
One way to judge the quality of a color-change stone is to plot the color panel pair in the CIE 1976 color circle. Good color-change pairings show a large hue angle difference, a small chroma difference, and large chroma values (Z. Sun et al., “How to facet gem-quality chrysoberyl: Clues from the relationship between color and pleochroism, with spectroscopic analysis and colorimetric parameters,” American Mineralogist, Vol. 102, No. 8, 2017, pp. 1747–1758). The color coordinates of the four stones in daylight-equivalent (D65) and incandescent (A) illumination were plotted in the CIE 1976 color circle (figure 4). Ethiopian grossular stone 4 had the largest hue angle difference among the four stones and a relatively small chroma difference. The non-Ethiopian tsavorite and demantoid both had a very small hue angle difference that was close to zero but with large chroma difference.
One interesting observation is that the Cr3+ absorption band shifted significantly from 627 in demantoid (stone 6) to 599 in the Ethiopian grossulars (stones 3 and 4; all stone samples contained little V). This shift opens a transmission window B in the red region shown in figure 2. To our knowledge, color-change behavior has not been reported in tsavorite or demantoid. This is because the absorption bands of V3+ at the 610 region in tsavorites (green grossular) or of Cr3+ at the 627 nm region are dominated by Cr3+ in demantoids and prevent the transmission of red light in these stones. In other words, there is no transmission window in the red for tsavorite or demantoid. However, these Ethiopian grossulars have little V3+, and the Cr3+ absorption is shifted away from the red region, which allows for significant transmission of red light through these stones. This creates a transmission window that produces significantly different color for the Ethiopian grossular in incandescent illumination versus daylight. To the authors’ knowledge this was the first group of color-change gem-quality chrome grossular garnet reported. @topic:1


Publish Year: - Title: Fall 2022 G&G Available Now Abstract: Get ready to uncover a wide range of topics in the Fall issue, from the challenges of determining the geographic origin of diamond to the use of gem materials as pigments in works of art. In addition to the four feature articles and our quarterly sections, we see the return of Diamond Reflections and the 2022 Gems & Gemology Challenge results.
METHODS AND CHALLENGES OF ESTABLISHING THE GEOGRAPHIC ORIGIN OF DIAMONDS
Diamond origin is a trending topic among consumers and the trade, as consumers seek to know the origin and the impact of purchased goods. The mounting push toward global sustainability has prompted direct efforts to use measurable characteristics to compare diamonds from different localities. The lead article by Evan Smith and coauthors discusses the recent methods and challenges associated with determining the geographic origin of diamonds and concludes that retaining origin information from the time of mining is the only definitive means of establishing provenance.
SAPPHIRE BENEATH THE RICH BLACK SOIL OF MULING, NORTHEASTERN CHINA
Yimiao Liu and Ren Lu characterize the gemological properties, chemical composition, and provenance-related features of sapphire found in Muling, northeastern China, comparing them against samples from other well-known corundum sources worldwide. Their research provides preliminary data to aid in the origin determination of this underexplored sapphire resource.
GEMS ON CANVAS: PIGMENTS HISTORICALLY SOURCED FROM GEM MATERIALS
Pigments derived from gem materials have been utilized for centuries, from ancient cave drawings to classical and modern works of art. These artistic creations reveal the evolution of the human experience and the progression of anthropological and chemical studies. In this article, Britni LeCroy examines the correlation between the evolution of gem pigment technology and historical art movements.
COLOR MECHANISM AND SPECTROSCOPIC THERMAL VARIATION OF PINK SPINEL REPORTEDLY FROM KUH-I-LAL, TAJIKISTAN
A team led by Yicen Liu uses spectroscopy and chemical analysis to study the color mechanism of pink spinel reportedly from the Kuh-i-Lal deposit in Tajikistan. When heated to a series of temperatures, the spinel samples showed that a combination of spectroscopic thermal variation characteristics causes their pink color.
LAB NOTES
GIA’s global laboratory staff present their latest findings in the Lab Notes section, including an exceptionally rare 1.21 ct Fancy orangy red diamond, a star sapphire from the legendary Kashmir deposit, and a synthetic moissanite carved to resemble a natural rough diamond.
MICRO-WORLD
The Micro-World section, dedicated to the inner world of gemstones, features an unusual bright purple fluid in rock crystal quartz, a partially exposed orange rutile crystal in a color-change diamond, and an eye-catching cluster of zircon needles in a stellate formation in Paraíba tourmaline.
DIAMOND REFLECTIONS
Diamond Reflections returns to examine the fluid droplets trapped within diamond during growth in the earth’s mantle. These liquids reflect the various natural processes that occur during diamond formation and provide scientists with a window into the great depths of our planet.
GEM NEWS INTERNATIONAL
Finally, GNI contributors report on saltwater cultured pearls containing non-traditional “box bead” nuclei fashioned from shell, a type of quartz featuring multiple color zones with oriented inclusions, an update on the current state of Mozambique’s ruby mines, and the first-ever Turquoise United conference. @topic:2


Publish Year: 1998 Title: Natural and Synthetic Rubies on the Basis of Trace-Element Chemistry Abstract: Natural and synthetic gem rubies can be separated on the basis of their trace-element chemistry as determined by energy-dispersive X-ray fluorescence (EDXRF) spectrometry. This method is especially important for rubies that do not have diagnostic inclusions or growth features, since such stones are difficult to identify using traditional gem testing methods. The results of this study indicate that the presence of nickel, molybdenum, lanthanum, tungsten, platinum, lead, or bismuth proves synthetic origin, but these elements were not detectable in most of the synthetic rubies tested. Alternatively, the concentrations of titanium, vanadium, iron, and gallium––considered together, as a trace-element “signature”––provide a means for separating nearly all synthetic from natural rubies. EDXRF can also help identify the geologic environment in which a ruby formed, and thus imply a geographic origin. @topic:3


Publish Year: 2018 Title: Quarterly Crystal: Wurtzite Phantom in Quartz Abstract: Figure 1. Measuring 86.38 mm and weighing 1,140 ct, this quartz crystal from British Columbia contains a three-sided phantom composed of an abundance of opaque black wurtzite inclusions. Photo by Robison McMurtry.
Transparent colorless rock crystal quartz is a strong, durable mineral that makes a favorable host for a wide variety of inclusions (see the three-volume Photoatlas of Inclusions in Gemstones for examples). The geographic source of the crystal pictured in figure 1 is British Columbia, Canada. At 1,140 ct and 86.38 mm in length, this large example of rock crystal plays host to several near-surface opaque black hexagonal to trigonal crystals as large as 5.0 mm.
As shown in figure 2, the micromorphology of the numerous inclusions, forming a three-sided phantom, suggests that they might be the zinc iron sulfide wurtzite. Laser Raman microspectrometry confirmed the identification of the inclusions as wurtzite. The euhedral inclusions were situated in the quartz crystal in the form of directional phantoms that developed through the directional deposition of the wurtzite on three consecutive surfaces of the quartz, which then continued to grow, enveloping the wurtzite as inclusion planes tracing the form of the original quartz host. From what we can determine, this is the first time that wurtzite has been found as an inclusion in any gem material. Because of wurtzite’s relationship to sphalerite, some inclusions previously identified as sphalerite may actually be wurtzite.

Figure 2. The crystals in this phantom plane in quartz were identified by Raman analysis as wurtzite. Photomicrograph by Nathan Renfro; field of view 19.2 mm. @topic:1


Publish Year: - Title: Postdoctoral Program Gives Scientists Access to Rare Research Opportunities Abstract: Evan Smith, whose expertise is in diamond geology, is systematically characterizing the inclusions he sees in rare types of diamonds to fill in some of the missing pieces in our understanding of how diamonds form and what they mean for the evolution of the planet. Photo by Siu Bo Wong Huang /GIA

Evan M.Smith was “blown away” by the first big diamonds he was able to work with at GIA.

“I was used to working with much smaller, lower-quality diamonds,” says Smith, who began working in the research department in New York in 2015. “I was very excited to be able to peek behind the curtain to see the variety of diamonds − and the very expensive ones − that are impossible to access for research anywhere else.”

Smith, whose expertise is in diamond geology, is working at GIA as part of the Richard T. Liddicoat Postdoctoral Research Fellowship program, which was created in 2014 in honor of GIA’s former president, who was widely considered the “Father of Modern Gemology.” It gives researchers who study mineralogy, geology, physics, materials science and other fields related to gemology access to GIA’s gemological data, equipment and the rare, unusual and large gems that come into the laboratories. Each position is tailored to focus on the research fellow’s expertise and interest with the opportunity to examine fundamental issues related to diamonds, colored stones, pearls and instrument development.

“We have had the opportunity to bring in some exceptional and highly motivated academic researchers through this program,” says Dr. Wuyi Wang, GIA’s director of research and development. The postdoctoral researchers work side-by-side with the Institute’s experienced researchers and gemologists, and together, they explore and learn from the gems that come into GIA’s lab.

The Liddicoat Postdoctoral Research Fellowship program is part of GIA’s extensive and ongoing research into the characteristics of diamonds and other gems. To that end, Liddicoat Postdoctoral Research Fellows are expected to conduct creative, independent, publishable research and are strongly encouraged to collaborate with GIA scientists as well as outside research institutions and universities.

Smith says the opportunities he has had to see some very rare diamonds and to learn from “the wealth of experience of people who have spent years inspecting and observing diamonds” will hopefully help him “shed some light on some aspects of diamond geology that perhaps have gone unnoticed by the geological community.”
Evan Smith: Diamond Inclusions and the Clues to the Earth’s Formation
Evan M. Smith, originally from Canada, near Toronto, specializes in diamond geology, which he says covers everything from the processes that make diamonds deep in the earth, to the ones that bring them to surface. As a geologist, he uses diamonds to help him understand how the Earth formed.

“Diamonds are a physical sample of carbon from the deep earth, and carbon is intimately involved in the evolution of the earth as we know it, from 4.6 billion years ago to today,” he says. “This means that diamonds give us a record of a broad range of processes, such as the formation of continents and the beginnings of plate tectonics.”

He worked in the mineral exploration industry looking for deposits of gold, or copper or other commodities after college and then at the Ekati diamond mine in northern Canada characterizing the various details of the rocks that contain diamonds. He became interested in the postdoctoral research program at GIA because of the potential to study diamonds that would otherwise be difficult – or impossible – for him to access.

“Diamonds are one of the most scientifically valuable minerals on the planet, but getting access to them for research purposes is often challenging because of their great value as gemstones,” he says. “The large numbers of diamonds that come through GIA for grading means that rare and unusual diamonds are almost a routine occurrence here.”

Smith is focused on inclusions in diamonds, materials the diamond has brought to the surface.

“When diamonds grow, sometimes they trap pieces of the surrounding minerals or fluid deep in the earth. When I say deep, I mean about 100 miles into the earth, and in some cases perhaps even all the way down to the core-mantle boundary at about 1,798 miles,” he says. “When diamonds are carried to the surface in a volcanic eruption, the diamond acts to protect and shield any inclusions trapped inside. No other mineral can provide such pristine samples of the deep earth.”

Smith is systematically characterizing the inclusions he sees in rare types of diamonds to fill in some of the missing pieces in our understanding of how diamonds form and what they mean for the evolution of the planet. He says that before he came to GIA, he was limited to working on smaller, less valuable diamonds, which is a problem because some particularly large, high quality diamonds might form in a different and unique way. Being able to access a wide variety of diamonds at GIA gives him the opportunity to see diamonds that have formed in a broader range of geological settings.

Smith is also searching for fluid in diamonds, such as nitrogen, water, carbon dioxide and methane, which also provide clues as to what happens deep in the Earth.

“A few years ago, I identified very small inclusions of liquid nitrogen trapped in diamonds from at least three different continents. The nitrogen is held under tremendous pressure, which allows it to be in liquid form at room temperature,” he says. “These fluids give clues about how different kinds of diamonds form and even how the atmosphere formed and changed over time.”

Smith says the diamond research he does – and the clues to the Earth’s formation he is seeking – would not be possible if people didn’t want diamonds for their jewelry.

“The desirability of diamond as a gemstone is the very reason it is mined. Otherwise, diamonds would remain buried in rocks and hidden in river gravels,” he says. “Nobody would ever get to study them or discover their fascinating secrets about the Earth.”
Elena Sorokina: The Genesis and Evolution of Corundum
Elena Sorokina, from Russia, graduated from the Russian State Geological prospecting University (MGRI - RSGPU) in Moscow in 2007 and started her Ph.D. program in gemology. She continued her Ph.D. education when she transferred to the Fedorovsky All-Russian Research Institute of Mineral Resources (FGUP VIMS) in 2009 as a junior researcher. In FGUP VIMS, she worked as a classical mineralogist conducting research on ore deposits from the geological prospecting stage to studying ore processing products.

Sorokina joined the Fersman Mineralogical Museum of the Russian Academy of Sciences in Moscow as a research fellow in 2012. After a scholarship award by the German Academic Exchange Service (DAAD), she became a visiting researcher (2013-2014) at the Center of Gem-Materials Research in Johannes Gutenberg University Mainz in Germany, which is an active part of Institute of Gemstone Research Idar-Oberstein. In University Mainz, her research experience extended to non- and micro-destructive technique, such as a laser ablation-inductively coupled plasma-mass spectrometry and different spectroscopic equipment.

Sorokina became a postdoctoral research fellow at GIA in Carlsbad in September 2015 and is focusing on the theories and ideas about the genesis and evolution of gem corundum, as well as mineral development within crystalline materials in natural environments. She is studying the questions related to the mineral crystallization and/or recrystallization, growth and purification during geological events.

“GIA provides excellent opportunities for young scientists at their early-career stage, allowing them to demonstrate the level of independence required to develop competitive and innovation research,” she says. “All the facilities and equipment are available from the GIA laboratories in New York and Carlsbad, including non- and micro-destructive techniques, which are a great advantage in studying gemstones.”

The major focus of Sorokina’s research lies across different science disciplines – gemology, mineralogy, geology, materials science and engineering.

“GIA provides the perfect environment for inter-disciplinary collaborative work in this area, getting more facilities for excellent research and internationalization,” says Sorokina, who left GIA in the fall of 2016 to pursue gemological research in Russia.
Aaron Palke: Applied Mineralogy and Gemstone Formation
Aaron Palke, like many scientists who decide to study Earth sciences, vividly remembers spending his summers collecting rocks.

“I became fascinated by Montana’s majestic mountain ranges and I was always raring to go collecting minerals with my father,” he says. “So naturally I decided to become a geologist.”

Palke studied mineralogy for his Ph.D. and focused on spectroscopic techniques (especially Nuclear Magnetic Resonance) to investigate the atomic-range structure of minerals during this time.

He was intrigued when he learned about GIA’s Liddicoat Postdoctoral Research Fellowship program when he was deciding on what he was going to do next.

“The program seemed like a natural choice for someone with my interests as gemology belongs essentially to the field of applied mineralogy,” he says. “My research at GIA has predominantly focused on using trace element chemistry and gemstone inclusion suites to pursue research into gemstone formation. I have been using GIA’s LA-ICP-MS facilities to analyze unusual trace elements in gem corundum, as well as analyzing inclusions in sapphires to understand the geological conditions of formation for these deposits.”

His work on melt inclusions in Yogo and other Montana sapphires, in particular, has provided some evidence for their formation through partial melting of Al-rich lower crystal rocks.

Palke credits GIA with giving him invaluable experience and access to gemological information to help advance his career. He said his time at GIA will serve him well in his new position at the University of Queensland and the Queensland Museum, where he will start later this year.

“There is probably no other place where a young scientist can have access to the resources GIA offers in terms of lab equipment, samples to work on and people with unique talents and knowledge to work with,” he says.

Learn about the requirements and application process for the Liddicoat Postdoctoral Research Fellowship or email researchcareers@gia.edu for more information. @topic:6


Publish Year: 2022 Title: Brilliance Exhibit at the Natural History Museum of Los Angeles County Abstract: Figure 1. Inside the vault room of the Brilliance: The Art and Science of Rare Jewels exhibit. Photo courtesy of the Natural History Museum of Los Angeles County.
A special exhibit of rare gems and minerals, entitled Brilliance: The Art and Science of Rare Jewels, was recently displayed at the Natural History Museum of Los Angeles County. The exhibit was available for viewing from December 8, 2021, through February 21, 2022, in the Gem Vault in the museum’s Gem and Mineral Hall (figure 1). Over one hundred spectacular objects—necklaces, bracelets, rings, earrings, and unmounted gems (many the creations of master jewelry designer Robert Procop)—were on display along with mineral specimens from the museum’s collection. Colorless and fancy-color diamonds, rubies, sapphires, emeralds, as well as color-change and asteriated gems and other spectacular specimens, were represented (figures 2 and 3). By allowing the public to view and appreciate these unique treasures, this museum event provided an understanding of how gems and minerals are used today in a variety of fields, from jewelry design to scientific research. Crystals of gem minerals represent products of some optimum conditions for natural mineral formation, and the study of rough and faceted gems is increasingly used by scientists today to better understand Earth’s history.

Figure 2. Left: The 46.39 ct Fancy blue Celeste diamond and a 100.92 ct colorless diamond were but two of the exquisite gems on display at the Natural History Museum of Los Angeles County. Right: This 108.03 ct blue sapphire from Sri Lanka is exceptional in terms of its clarity, color, and size. Photos courtesy of the Natural History Museum of Los Angeles County; courtesy of Robert Procop.

Figure 3. The 79.39 ct Royal Pink sapphire is, according to the designer, the largest vivid natural pink sapphire in the world. Courtesy of Robert Procop. @topic:8


Publish Year: - Title: Summer 2022 G&G Available Now Abstract: The Summer issue of G&G is bursting with new content! Three feature articles characterize gemstones—diamonds, amber, and nephrite, respectively—from known sources and offer the means to distinguish their geographic origin. Two additional full-length articles analyze gems from the coronation crown of Napoleon III and the unusual surface features of ekanite from Sri Lanka. Meanwhile, the journal’s regular sections continue to delight with interesting finds from around the world.
A LOOK AT DIAMONDS AND DIAMOND MINING IN GUYANA
The lead article by Roy Bassoo and Kenneth Befus combines direct observations, government reports, and historical accounts to provide a detailed gemological description of diamonds from Guyana. Their overview of diamond production describes the morphology, chemical content, and luminescence features of these alluvial diamonds prized for their clarity and color.
THE SHAPE OF EKANITE
Lutz Nasdala and coauthors characterize the physical properties, chemical composition, and general appearance of ekanite found in Ampegama, Sri Lanka, comparing them against samples from other deposits in the country. The remarkably uneven shapes and bumpy surface features of these ekanite fragments lead them to identify the processes responsible for the distinctive appearance.
A GEMOLOGICAL AND SPECTROSCOPIC STUDY WITH MOBILE INSTRUMENTS OF “EMERALDS” FROM THE CORONATION CROWN OF NAPOLEON III
In an effort to examine gemstones of historical significance, Stefanos Karampelas and fellow researchers use nondestructive mobile gemological and spectroscopic instruments to analyze 45 “emeralds” formerly set in the coronation crown of Napoleon III. Their efforts uncover the true identity of these gems, verifying that 41 are indeed natural emerald, probably of Colombian origin, while the remaining four are artificial glass.
CHARACTERISTICS OF NEWLY DISCOVERED AMBER FROM PHU QUOC, VIETNAM
A team led by Le Ngoc Nang discovers an amber deposit amid sandstone boulders on the island of Phu Quoc, Vietnam’s only known amber locality to date. Their article presents the gemological properties of this newly sourced amber and shows that FTIR spectroscopy can differentiate Phu Quoc from other global sources.
NATURAL RADIOACTIVITY IN SELECT SERPENTINITE-RELATED NEPHRITE SAMPLES: A COMPARISON WITH DOLOMITE-RELATED NEPHRITE
Dariusz Malzcewski and coauthors use low-background gamma-ray spectrometry to measure potassium, thorium, and uranium activity concentrations in nephrite from Poland, Russia, Canada, and New Zealand. Their studies prove that Th/U ratios appear unique according to geographic region. In addition, they conclude that nephrite does not pose a radiological risk to artisans or collectors who handle this ornamental material.
LAB NOTES
GIA’s global laboratory staff present their latest findings in the Lab Notes section, including an exceptionally rare 2.29 ct bright orange benitoite, the internally flawless 15.10 ct De Beers Cullinan Blue diamond, and a color-change sapphire exhibiting both asterism and chatoyancy.
MICRO-WORLD
The Micro-World section, dedicated to the inner world of gemstones, features a blue apatite crystal beautifully framed by rutile needles in garnet, an extensive network of eye-visible etch channels in diamond, and a labyrinth pattern in the fracture filling of an emerald.
COLORED STONES UNEARTHED
Colored Stones Unearthed returns to explore the fascinating realm of inclusions in gemstones. The microscopic inclusions within a gemstone can reveal a great deal about the host material. In this installment, learn how inclusions form, how they are studied, and what information gemologists and geoscientists can uncover.
GEM NEWS INTERNATIONAL
Finally, GNI contributors report on various topics ranging from gem identification to responsible practices to auction and museum highlights. Two entries feature gems that can change color—a photochromic zircon that reacted after exposure to long-wave UV and two sapphires that shifted between orange and yellow hues, providing an interesting case study on color stability. Gain insight on creating a sustainable and responsible emerald industry with Myne London, an ethical emerald supplier with a goal of supporting women’s economic empowerment in the gem trade. Finally, the spring 2022 auction season was buzzing with plenty of top-notch gems on the block, including two diamonds weighing more than 200 ct each and several gems fetching record prices. @topic:2


Publish Year: 2022 Title: Tucson 2022 Overview Abstract: Figure 1. Customers select goods at the AGTA GemFair. Photo by Tao Hsu.
Sellers and buyers alike were delighted to be back at Tucson for the show season after a two-year absence. As the world enters a new phase of the pandemic, the gem and jewelry industry is also preparing for the post-pandemic era. Attendees embraced precautions such as social distancing and face coverings (figure 1). Although social gatherings were much less crowded than usual, the atmosphere and business at the shows were as strong as before, if not better.
Due to travel restrictions, the international presence was down, but that did not affect vendor attendance at the main AGTA GemFair at the Tucson Convention Center, where the majority of exhibitors had strong U.S. representation. The Gem & Jewelry Exchange (GJX) show was slightly affected, with some booths left empty by foreign dealers who could not make it to Tucson this year. Vendor attendance in the satellite shows outside of the convention center area remained strong, as observed by the authors at the Pueblo Gem & Mineral Show, the Kino Gem & Mineral Show (figure 2), and the 22nd Street Mineral, Fossil, Gem & Jewelry Show.

Figure 2. A stone decor dealer’s booth at the Kino Gem & Mineral Show. Open to the public, the show saw steady foot traffic. Photo by Tao Hsu.
Many exhibitors felt that while foot traffic was lighter than usual, buyers were focused on purchasing targeted goods to restock inventory. Meanwhile, the pandemic’s influence on the supply side of the value chain was just starting to show. Therefore, this Tucson show season provided a very good opportunity to prepare for a potential shortage in the coming months (figure 3).

Figure 3. Left: The Pueblo Gem & Mineral Show was an ideal place to source rough gems of all kinds. Right: Cutting services were provided at multiple shows open to the public. Photos by Tao Hsu.
The variety of gems and jewelry traded at the shows remained consistent with previous years. The “big three”—ruby, sapphire, and emerald—still dominate the market (figure 4), with the intake at the GIA Show Service Lab reflecting this. Collector minerals and gems such as meteorite, gahnospinel, fluorite of various colors, opalized fossils, cerussite, and colemanite continued to attract a niche market clientele (figure 5). Also in high demand were fantasy cuts, rose cuts, briolettes, and mineral or rock slices. Jewelry designers on a mission to fulfill special orders sourced gems such as Montana sapphire, Oregon sunstone, Arizona turquoise, Washington nephrite jade, and other American gems.

Figure 4. An 8.23 ct star ruby cut by David Nassi. Photo by Robert Weldon; courtesy of 100% Natural Ltd.

Figure 5. A 45 ct green fluorite from New Mexico. Dealers carried fluorite of all colors and cutting styles at both the AGTA and GJX shows. Photo by Emily Lane; courtesy of Barker & Co.
Vendors have never been more creative in terms of their products and business savvy. To fulfill the ever-growing demand for one-of-a-kind creations, gem cutters, carvers, and jewelry manufacturers have put more thought and individuality into their pieces (figure 6). Products manufactured with a high level of sophistication such as inlaid jewelry or gems were prominent at the show (figure 7). Many vendors have shifted more business online over the past two years to combat limited foot traffic in stores. Newly formed companies, meanwhile, have often started completely online or done most of their business online.

Figure 6. Left: Rock and metal wall decor in combination with metal art at the Kino show. Right: A 22.93 ct carved citrine crafted in Jaipur, India; courtesy of Artisav Jaipur. Photos by Tao Hsu.

Figure 7. Gemstone-inlaid bangles from David R. Freeland Jr. Designs at the Pueblo Gem & Mineral Show. Photo by Lisa Kennedy.
GIA relished in the much-anticipated return to Tucson this year, enthusiastically gathering the latest from the shows to share in this report. Our coverage includes market updates, interesting and noteworthy finds, and uplifting accounts from dealers, cutters, designers, and more.
The following contributed to this report: Erin Hogarth, Erica Zaidman, Robert Weldon, Albert Salvato, Wim Vertriest, Lisa Neely, and Nathan Renfro.

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Photo Highlights from the 2022 Tucson Shows @topic:11


Publish Year: - Title: Spring 2022 G&G Available Now Abstract: A variety of topics are in store for you in the Spring issue of G&G. The first article provides a comprehensive summary of mineral, chemical, and spectroscopic investigations of Schneckenstein topaz. The second article concludes the investigation into the early mining history of the Habachtal emerald deposit in Austria with a look at the era between World Wars I and II. This issue also marks G&G’s return to the Tucson gem shows in early 2022 and the debut of an exciting new section: Diamond Reflections.
GEM TOPAZ FROM THE SCHNECKENSTEIN CRAIG, SAXONY, GERMANY: MINERALOGICAL CHARACTERIZATION AND LUMINESCENCE
The lead article by Manuela Zeug and coauthors provides a mineral-chemical and spectroscopic characterization of yellow topaz from the Schneckenstein crag in Saxony, Germany. This study utilizes excitation-emission spectroscopy to explain the photoluminescence behavior of the material, which appears virtually inert under common UV sources.
HISTORY OF EMERALD MINING IN THE HABACHTAL DEPOSIT OF AUSTRIA, PART II
Karl Schmetzer details the mining history of Austria’s Habachtal region to conclude this two-part series. This article presents research using largely unpublished materials from Austrian and German archives to illustrate the mining problems and the success or failure of those involved with emerald recovery in the era between World War I and World War II.
LAB NOTES
GIA laboratory staff members present their latest findings in the Lab Notes section, including a natural type Ia diamond that changed from Fancy Dark yellowish brown to Fancy Deep yellow-orange with HPHT processing, three green and yellow diamonds over 5 carats colored by nickel impurities, a record size for a CVD laboratory-grown diamond, and unusual laser drill holes in an HPHT-grown synthetic diamond.
MICRO-WORLD
The Micro-World section, dedicated to the inner world of gemstones, features an apatite before and after oiling, a large red garnet crystal within an aquamarine, magnificent cube-shaped cavities and purple fluorite in hyalite, and a complex fluid inclusion in topaz.
DIAMOND REFLECTIONS
The debut of Evan Smith’s new G&G column explores the connection between deep-focus earthquakes, those originating below the rigid tectonic plates, and diamond growth. If these two processes are related, then modern-day earthquakes have the potential to produce valuable diamonds of large sizes. Future installments of this section will appear on a periodic basis.
GEM NEWS INTERNATIONAL
Finally, GNI correspondents from around the world report on market updates, interesting and noteworthy finds, and interviews with dealers, cutters, and designers, in more than 30 pages of coverage from the 2022 Tucson gem shows. Other highlights from the section include an unusual repair of a natural emerald, inclusions and spectroscopic features of yellowish green enstatite, and the discovery of davemaoite in a diamond from the earth’s lower mantle.
The Spring issue also contains the 2022 Gems & Gemology Challenge. Score 75% or better, and you’ll receive a certificate of completion; earn a perfect score, and your name will be listed in the Fall 2022 issue. Online entries for the Challenge must be submitted by Monday, August 1, 2022. @topic:8


Publish Year: 2022 Title: Yellow Topaz from Germany, Emerald Mining in Austria’s Habachtal Region, a Return to Tucson, and More… Abstract: Welcome to the Spring 2022 issue of Gems & Gemology! For our industry, February is marked by the Tucson gem shows, and we’re delighted to share content from our highly anticipated return to Tucson. With our two feature articles, our regular columns, the debut of a new regular feature, and the annual G&G Challenge, there’s something for everyone in this issue.
In our lead article, Manuela Zeug and coauthors explore yellow topaz from the Schneckenstein crag in Saxony, Germany. The article provides a comprehensive summary of mineral, chemical, and spectroscopic investigations of Schneckenstein topaz, with an emphasis on luminescence studied by excitation-emission spectroscopy. This study offers a new perspective on previous mineralogical studies, which focused mainly on crystal forms and trace element geochemistry.
Our second feature article revisits the history of emerald mining in Austria’s Habachtal region. In the second installment of his two-part series, Karl Schmetzer traces the history of the Habachtal mine during the era between World Wars I and II, using a variety of largely unpublished sources from Austrian and German archives.
“We’re delighted to share content from our highly anticipated return to Tucson.”
Our regular features have much to offer, too. Among the variety of snapshots in Lab Notes, we report on two notable laboratory-grown diamonds recently examined by GIA: a new record-size CVD diamond and one with unusual laser drill holes. Micro-World offers a glimpse into the inner landscapes of gemstones, including a before-and-after comparison of an oiled apatite cabochon, a complex fluid inclusion in topaz, and a garnet crystal inclusion in aquamarine. Our Gem News International section features more than 30 pages of coverage from the 2022 Tucson shows, with market updates, interesting and noteworthy finds, and interviews with dealers, cutters, and designers. Other highlights from Gem News International include a study of irradiation treatment in amber and the discovery of davemaoite in a diamond from the earth’s lower mantle.
This issue also includes the debut of an exciting new section: Diamond Reflections. In his first installment, Evan M. Smith explores the potential role of modern-day deep-focus earthquakes on diamond growth.
Also in this issue: Be sure to take the annual G&G Challenge quiz, which offers the chance to test your gemological knowledge of our feature articles from 2021. And we congratulate the winners of this year’s Dr. Edward J. Gübelin Most Valuable Article Award.
We hope you enjoy the Spring edition of Gems & Gemology! @topic:2


Publish Year: - Title: GIA’s First Research Intern: Genesis of a Gemologist Abstract: Rachelle Turnier used Raman spectroscopy and photoluminescence mapping to better understand the formation of basalt-related sapphires, the focus of her Ph.D. work. Photo by Kevin Schumacher/GIA.

Rachelle Turnier, GIA’s first research intern, began her undergraduate studies in geology, but a fellowship at the American Museum of Natural History turned her interests to gemology. Her work there with curator George Harlow on determining the geological origins of syenite-hosted sapphires made her realize that a geology degree could apply to the world of gems.

“Gemstones are beautiful minerals,” Turnier says. “Not too many geologists are gem-focused. There was obviously a hole that needed to be filled.”

GIA’s Research Internship Program is the first for undergraduate and graduate students. The Institute also offers the Richard T. Liddicoat Postdoctoral Research Associate Fellowship, founded in 2014, for postdoctoral researchers.

Turnier, who was a first-year Ph.D. student in geochemistry and petrology at the University of Wisconsin–Madison when she interned at GIA in late 2017, researched the geological conditions of basalt-related sapphire formation. Many sapphires are found in alluvial deposits after they weather away from the host rock, leaving only the geochemistry of the sapphires and their inclusions to give clues about their formation.

During her two-and-a-half-month internship, Turnier used GIA’s extensive gem reference collection to document zircon inclusions in sapphire samples, analyzing them with Raman spectroscopy to determine at what depths the stones formed. She also used photoluminescence (PL) mapping to determine whether spectroscopic and growth features unique to sapphires from different deposits exist, finding vastly different PL intensities between Thai and Cambodian sapphires. This shows promise as a factor that could aid in country-of-origin determination, but further studies are needed.

“We have field gemologists choosing samples from the source at all these deposits,” says Aaron Palke, a senior research scientist at GIA who worked closely with Turnier. “One of the things we want to do is to bring in outside researchers to help us find the most value in the gem reference collection.”

Turnier returned to the University of Wisconsin and is researching oxygen isotopes in the zircon inclusions and the host sapphire. Using a secondary ion mass spectrometer, she is working to determine when and through what geologic processes the sapphires and inclusions formed.
“I just love instrumentation,” Turnier says. “And what better thing to do than study pretty rocks and minerals on cool instruments?”

The one- to two-month Research Internship Program is offered at GIA’s Carlsbad and New York locations. Candidates should be pursuing a bachelor’s or graduate degree in physics, materials science, geology, chemistry, or a related field and must be in their junior year or higher. Selected interns will work on a defined project and be mentored in spectroscopy and gemology by GIA research scientists and gemologists. A project conclusion will be reached by the end of the internship. An extension of the internship is possible.

Three interns are at work in the Carlsbad laboratory in 2018, studying color in ruby and sapphire, color in copper-bearing feldspar, and the spectroscopic signatures of yellow diamonds from Canada. The New York lab recently hosted an intern focusing on point defects in mineral-included superdeep type IIa diamonds from Juina, Brazil, and, early next year, a second will investigate color-forming defects in unusual yellow- and brown-grained type IaAB diamonds from Botswana.

Find out more about the GIA research internship program, qualifications, and application process. @topic:2


Publish Year: 2021 Title: Burmese Blue Sapphire and Peridot from Mogok and a History of Emerald Mining in Habachtal, Austria Abstract: Welcome to the Winter 2021 issue of Gems & Gemology! This exciting conclusion to the volume year features new content examining blue Burmese sapphires, the source of rich olive color peridot in Pyaung-Gaung, and the history of emerald mining in Austria’s Habachtal region.
“…an extensive gemological analysis of 248 blue sapphires from Mogok…”
Our lead article by Wasura Soonthorntantikul and coauthors features an extensive gemological analysis of 248 blue sapphires from Mogok, a source long known for producing high-grade material. This study uses samples collected on a series of expeditions by GIA’s field gemologists over the last decade, filling a gap in modern analytical data. Findings indicate that the sapphires show a wide range of blue color intensities but maintain a very consistent inclusion scene.
Next, Montira Seneewong-Na-Ayutthaya and fellow researchers investigate the internal, spectroscopic, and chemical features of peridot from the Pyaung-Gaung area in the Mogok township of Myanmar. This location is an essential source of high-quality peridot, producing rough both large in size and rich in olive green color. A combination of various gemological tests and advanced analytical methods presented in this study prove effective in differentiating Pyauang-Gaung peridot from other sources.
The final article delves into the mining history of Austria’s Habachtal region, which is considered one of the early emerald deposits, with references dating back to 1797. In part one of this two-part series, Karl Schmetzer traces the history of the Habachtal emerald mine through several centuries up to World War I, using largely unpublished works sourced from Austrian and German archives.
As always, our regular columns offer an assortment of gemological findings from around the globe. Highlights of the Lab Notes section include an impressive diamond faceted as the iconic Apple Inc. logo, exquisite antique spectacles crafted with diamond and emerald lenses in mid-seventeenth-century India, and an exceptionally large and well-saturated orange sapphire from Sri Lanka. The Micro-World section presents a demantoid faceted to showcase spectacular “horsetail” inclusions, a remarkable example of rainbow graining in a yellow diamond, and an unusual occurrence of a hematite crystal hosting a network of rutile crystals. In Gem News International, stay up to date with recent studies on biogenic carbon in pink corundum from southern West Greenland, the latest on mining the Yogo sapphire deposit in Montana, and a new blue zircon deposit discovered in Malawi.
Finally, this issue includes the debut of an exciting addition to our regular columns, Colored Stones Unearthed, exploring the formation of colored stones from the crust-mantle and below. This first installment covers some of the gemstones that provide important information on the mineralogy, composition, and evolution of the earth, including peridot, sapphire, and ruby.
We hope you enjoy the Winter issue of Gems & Gemology! @topic:2


Publish Year: - Title: Winter 2021 G&G Available Now Abstract: The Winter issue presents two characterization studies on gems from Mogok. These feature articles use Burmese blue sapphire and peridot of known provenance to enhance the current gemological knowledge base for origin separation. The third article combs through the early mining history of the Habachtal emerald deposit in Austria up to the beginning of World War I.
Blue Sapphires from Mogok, Myanmar: A Gemological Review
The lead article by Wasura Soonthorntantikul and co-authors investigates 248 blue sapphires collected from different areas in the Mogok Stone Tract by GIA field gemologists over five years. The gemological and chemical characterization indicates a wide range of blue color intensities, very consistent inclusion scenes, and no significant trace element differences between various sapphire-producing zones in Mogok. Such studies on reliable samples support the increasing demand for origin determination services by gemological laboratories.
Gemological Characterization of Peridot from Pyaung-Gaung in Mogok, Myanmar
Myanmar produces high-quality peridot of considerable size that possesses an attractive deep olive green color. A research team led by Montira Seneewong-Na-Ayutthaya examines peridot from the Pyaung-Gaung area and provides diagnostic inclusions and trace element chemistry that can separate this material from deposits in China and Pakistan.
History of Emerald Mining in the Habachtal Deposit of Austria, Part I
Karl Schmetzer details the mining history of Austria’s Habachtal region in part one of this two-part series. This article presents research using largely unpublished materials from Austrian and German archives to trace the various ownership transitions of this early emerald deposit.
Lab Notes
GIA laboratory staff members present their latest findings in the Lab Notes section, including a diamond faceted as the iconic Apple logo, two pairs of antique Mughal spectacles with diamond and emerald lenses, and tourmaline featuring a unique surface pattern resembling a circuit board.
Micro-World
The Micro-World section, dedicated to the inner world of gemstones, features a chondrodite crystal in Burmese red spinel, an excellent example of a polyp structure in natural black coral, spectacular wispy “horsetail” inclusions in demantoid, and a tourmaline with abundant colorless zoning with windmill structures.
Colored Stones Unearthed
Colored gemstone deposits are geologically diverse and provide important information on the composition and evolution of the earth. The debut of this new G&G column explores geological concepts related to the formation of colored stones from the crust-mantle transition and below. Future installments will appear on a periodic basis.
Gem News International
Finally, GNI correspondents from around the world report on renewed interest in mining activity at the Yogo sapphire deposit in Montana, the identification of blue zircon supposedly from a new deposit in Malawi, Rio Tinto’s final sale of pink and blue diamonds from Argyle, and “floating flower” inclusions in a bangle fashioned from aventurine quartz. @topic:2


Publish Year: 2021 Title: Epoxy-Filled Chalcedony as an Imitation for “Candy Agate” Abstract: Figure 1. Rough stones of candy agate from the Alxa Plateau of Inner Mongolia are usually found in irregular shapes and granular gravels, as shown in this picture. Photo by Shu-Hong Lin.
A special kind of agate known as “candy agate” is produced in the Alxa Plateau of Inner Mongolia. This type of agate usually comes in irregular shapes and granular gravels, with a diameter ranging from several millimeters to several centimeters (figure 1). In addition to a variety of bodycolors, these agates occasionally present color zoning between the inner core and the outer layer. These candy agates have been very popular during the past few years, especially in the Taiwan market.

Figure 2. A string of beads submitted to TULAB as “candy agate.” Photo by Kai-Yun Huang.
Recently, several strings of beads were submitted to the Taiwan Union Lab of Gem Research (TULAB) as candy agate (figure 2). The outer layer of the beads was colorless and semitransparent, and the inner core presented various colors of green, purple, orange, yellow, or greenish blue. These agate beads did not have any fissures extending from the surface to the inner core but only a drill hole penetrating each bead so they could be threaded together to make a bracelet. Gemological testing identified the beads as chalcedony, but the unusually bright color of their inner cores looked unnatural and thus aroused suspicion.

Figure 3. The Raman spectra of the outer layer and the inner core of the beads matched those expected for chalcedony (K.J. Kingma and R.J. Hemley, “Raman spectroscopic study of microcrystalline silica,” American Mineralogist, Vol. 79, 1994, pp. 269–273) and epoxy resin (K.E. Chike et al., “Raman and near-infrared studies of an epoxy resin,” Applied Spectroscopy, Vol. 47, No. 10, 1993, pp. 1631–1635). The stacked spectra are baseline-corrected and normalized.

Figure 4. One bead showed a few bubble inclusions in its orange core. Photomicrograph by Shu-Hong Lin; field of view 3.06 mm.

Figure 5. A greenish blue bead cut in half revealed its drill hole (A), greenish blue epoxy filling (B), and colorless chalcedony (C). Photomicrograph by Yu-Shan Chou; field of view 2.83 mm.
To verify whether the center color of these beads was natural, the beads were further analyzed by Raman spectroscopy with 785 nm laser excitation at the surface and about 1–2 mm deep into the colored inner core. Comparisons of the resulting spectra with those reported in previously published studies identified the materials as chalcedony and epoxy resin (figure 3), which means that these “candy agates” were likely chalcedony beads hollowed out and filled with colored epoxy resin. Under microscopic observation (figure 4), some of the beads even had bubble inclusions in their inner cores, further supporting the possibility of epoxy filling. To understand how these beads were made, we asked the owner to provide samples cut in half for further testing. Microscopic observation of the cross-sections revealed that the beads were somehow hollowed out through the drill hole and then filled with colored epoxy resin (figure 5). Finally, a second drilling was performed along the original drill hole after the epoxy resin had hardened.
The colored inner core, which makes the agate special and valuable, is common in natural candy agate from the Alxa Plateau. The imitation candy agate in this study could be defined as a new type of epoxy-filled chalcedony which showed similar colored cores to natural candy agate. The most effective non-destructive methods for identifying this product are Raman spectroscopy and microscopic observation, but the results may be affected by the location of the inner core and the transparency of the chalcedony. @topic:2


Publish Year: 2021 Title: Update on Mining Activity at Yogo Gulch, Montana Abstract: Figure 1. Underground operations in the Vortex mine at Yogo Gulch, Montana. Photo by Don Baide.
The Yogo sapphire deposit, discovered more than 100 years ago, has seen renewed mining interest over the last few years. The fame of Yogo sapphires was established in the first few decades the deposit was worked by the London-based New Mine Sapphire Syndicate. Then, a catastrophic flood in 1923 destroyed the mine infrastructure and operations ground to a halt. Production was sparse and unpredictable for the next several decades. Notable events in the modern history of Yogo Gulch include the arrival of Chikara Kunisaki and the Roncor Corporation in 1973, which drilled the 3,000-foot Kunisaki tunnel at the old American mine, and the discovery of a new extension of the sapphire-bearing dike to the west of the deposit, which became the Vortex mine. Since 2017, there has been renewed interest in bringing back large-scale mining operations, and the authors had the chance to observe these activities firsthand in the summer of 2021.
In 2017, Don Baide, a jeweler out of Bozeman, acquired the Vortex mine and started revamping the underground operations to bring the mine back online. In the 1990s, a modern 3,000-foot spiral ramp descending 475 feet was installed at Vortex. Due to years of inactivity, Baide and his miners have had to spend considerable time pumping water out of the underground shafts and rehabilitating the mine, but they are now working through the winter down to the 400-foot level (figure 1). They have uncovered new exposures of the sapphire-bearing dike rock and expect to process ore from this level by the end of 2021.

Figure 2. A large portion of the Roncor property is home to the Gadsden house (lower left) and the eastern portion of the Yogo dike, which stretches for miles as a long trench (white arrow). Photo by Nathan Renfro.

Figure 3. A view up the valley known as Kelly Coulee to the west of Yogo Creek. Photo by Aaron Palke.
While Vortex is the most recently worked mine at Yogo Gulch, the bulk of the deposit lies to the east of Yogo Creek in what has become known as the Roncor property. This includes the old English mine at the far east of the deposit (figure 2), as well as the Kelly Coulee and the American mine (figure 3). In 2021, a new venture, Yogold U.S.A. Corporation, was created and acquired a lease to resume mining operations on the Roncor property. Yogold spent the summer mining open cuts of the Yogo dike as well as installing a washing plant to recover sapphires. Yogold is also actively rehabilitating the Kunisaki tunnel, which has been dormant for nearly 35 years. They plan to resume underground mining through the Kunisaki tunnel and significantly increase sapphire recovery underground.
The jewelry company Parle’ of Pocatello, Idaho, has a strategic partnership with Yogold to market loose stones and manufacture jewelry featuring Yogo sapphires. Also of interest, documentary filmmaker Orin Mazzoni is producing a short film featuring the Yogo deposit that should be of interest to anyone fascinated by these brilliant blue gems. The film is expected to be released in early 2022.

Figure 4. A miner shows off his collection of Yogo sapphires. Photo by Aaron Palke.
There are certainly many more treasures to be unearthed at this rich deposit. While Yogo sapphires often carry a premium in the gem market for their rich cornflower blue color (figure 4) and lack of treatment, the higher overhead costs of mining in the United States pose the main challenge. But with sustained and serious mining activity in progress, the gem trade may be seeing more of the famous Yogo sapphire in the coming years. @topic:9