# Publication Year: 2021
# Title: Mignone Halls of Gems and Minerals
# Abstract: Figure 1. One of the two giant amethyst geodes displayed at the entrance of the Mineral Hall. This geode weighs 11,000 lbs. (5,000 kg). Photo by Augusto Castillo.

The American Museum of Natural History in New York City has reopened one of the most beloved spaces for gem enthusiasts with the unveiling of the Allison and Roberto Mignone Halls of Gems and Minerals on June 12, 2021. After a four-year closure, the 11,000-square-foot halls, which house more than 5,000 specimens sourced from 98 countries, have been completely redesigned and reinstalled to tell the intriguing story of how mineral diversity arose on our planet. This exciting public event reflects the reopening of New York City.
The American Museum of Natural History has a long-standing history with minerals and gems that dates back to its founding in 1869. In the 45 years since the previous iteration of the gem and mineral halls opened, the scientific fields of mineralogy and geology have advanced significantly, and the new design reflects these advancements. The halls were organized by Dr. George E. Harlow, curator of the Department of Earth and Planetary Sciences, to showcase to the public the current scientific understanding of gems and minerals, the geological conditions and processes by which they form, and introduce the relatively novel concept of mineral evolution.

Figure 2. The Singing Stone is a massive 7,200 lb. (3265 kg) block composed of the copper ore minerals azurite and malachite. Its name comes from the high-pitched sounds produced when the stone absorbed and released moisture from the air. The stone no longer sings now that it sits in a controlled environment. Photo by Augusto Castillo.
Mineral evolution, one of the central themes, seeks to explain how more than 5,500 mineral species came into existence when there were no minerals for hundreds of millions of years after the Big Bang. The new halls show how changing conditions on Earth allowed more chemically diverse minerals to arise. They highlight one of the most important changes, which is the evolution of life that filled the atmosphere with free oxygen, enabling colorful, highly oxidized minerals. These are the same colorful minerals we associate with the gemstones humans have used to decorate themselves for thousands of years.
The redesigned space no longer resembles a simulated subterranean mine, with the multi-leveled carpeted interior that the previous iteration was known for. Instead, an open-floor concept allows visitors to wander seamlessly between the different displays and exhibits. It has three main divisions: the Mineral Hall, the Gem Hall, and the Melissa and Keith Meister Gallery for temporary exhibitions.

Figure 3. A towering 14,500 lb. (6,577 kg) slab studded with giant garnets. The garnets formed more than 1 billion years ago, when the original rock transformed at pressure 8,000 times greater than atmospheric pressure and at about 1500°F (815°C). Photo by Augusto Castillo.
Entering the Mineral Hall, the visitor is welcomed by a pair of towering amethyst geodes that formed nearly 135 million years ago (figure 1). The scale and rich purple color of the massive geodes command attention and set the tone for the rest of the space. Behind the geodes, the center of the Mineral Hall contains mineral specimens organized by formation environment: igneous, pegmatitic, metamorphic, hydrothermal, and weathering. Highlights include the Singing Stone, a massive block composed of blue azurite and green malachite that was collected in 1891 from Bisbee, Arizona (figure 2), and a 14,500 lb. slab from upstate New York that is studded with garnets measuring up to one foot across (figure 3).

Figure 4. The 563 ct Star of India, the world’s largest gem-quality blue star sapphire. Photo by D. Finnin/©AMNH.
The west wall of the Mineral Hall has a running display dedicated to the systematic classification of minerals. The display contains 659 specimens arranged by chemical composition, increasing in complexity across the wall. An interactive periodic table that can be used to explore forming minerals stands at the center of the west wall. The four corners of the Mineral Hall explore the overarching scientific concepts of minerals, from their evolution and diversity to their properties and how they have been used by humans from prehistory to the present day. Adjacent to the gallery of minerals and light is the Gem Hall. It features a dazzling display of nearly 2,500 objects, including precious stones, carvings, and jewelry from the museum’s world-class collection. Highlights include the 563 ct Star of India (figure 4), the largest gem-quality star sapphire known, and the 632 ct Patricia emerald, the largest gem-quality emerald reported from the Chivor mine in Colombia (figure 5).

Figure 5. The 632 ct Patricia emerald, discovered in 1920 by a local miner, is the largest gem-quality emerald reported from the Chivor mine in Colombia. Photo by D. Finnin/©AMNH.
In addition, the Melissa and Keith Meister Gallery is a rotating exhibit gallery newly added to the Halls of Gems and Minerals. Beautiful Creatures, curated by jewelry historian Marion Fasel, features animal-themed jewelry created over the last 150 years. The exhibit included more than 100 jewels from the world’s great jewelry houses organized into three categories: land, water, and air. Its time frame coincides with the founding of the American Museum of Natural History in 1869 and explores the extraordinary diversity of the animal kingdom and the inspiration that it has provided for jewelry designers. Beautiful Creatures is on display through September 19, 2021. @chapter:4 @chapter:0 @chapter:4


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

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

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

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

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

To view the full section, download the PDF above. @chapter:20 @chapter:2 @chapter:20


# Publication Year: 2023
# Title: Octahedral Gahnospinel Crystal in Sri Lankan Blue Sapphire
# Abstract: A greenish blue octahedral crystal of gahnospinel found in Sri Lankan blue sapphire. Photomicrograph by Yusuke Takamura; field of view 3.81 mm.
Recently, the authors encountered a greenish blue octahedral crystal inclusion in a Sri Lankan blue sapphire (see above). Visual features, such as the greenish blue color and octahedral shape, and Raman spectroscopy identified the inclusion as gahnospinel, with the formula (Mg,Zn)Al2O4.
Gahnospinel inclusions in sapphire often suggest a Sri Lankan origin (A.C. Palke et al., “Geographic origin determination of blue sapphire,” Winter 2019 G&G, pp. 536–579). In addition, gahnospinel inclusions with euhedral crystal shape have been reported previously (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Volume 3, Opinio Verlag, Basel, Switzerland, 2008). This crystal, however, shows large and beautiful octahedral features. @chapter:24 @chapter:0 @chapter:24


# Publication Year: -
# Title: 10 Vivid Gems Bring Fall Colors to Life
# Abstract: View Gallery

Color – the first of the 4Cs – is perhaps the most described characteristic in gems. From bright blues and steely greys to rich browns and fiery reds, gems come in many colors. The Pantone Color Institute, an arbiter of color for designers and fashionistas, selected 10 favorites for its fall 2013 color report. With exotic names like Acai, Samba and Mykonos Blue, these trendy colors are expected to dominate the fall season.

	But we think they look best in gems.

	The photo gallery above brings Pantone’s fall colors to life with gems that represent each shade. Explore vibrant pink sapphire, tourmaline the color of ocean waters and the 2013 color of the year: emerald. @chapter:40 @chapter:2 @chapter:40


# Publication Year: 2016
# Title: Update on Colored Gemstone Mining in Tanzania
# Abstract: Figure 1. A view of the pink sapphire mining pit at Kibuko, in the Uluguru Mountains of Tanzania. Photo by Vincent Pardieu/GIA.

	A team of GIA field gemologists visited Tanzanian mines in the summer of 2016 to collect ruby and sapphire for GIA’s reference collection and explore new sources of colored stones. The field expedition, led by these authors, visited many known Tanzanian gem localities as well as new deposits at Loolera, Kibuko (figure 1), Lutela, Amani Makoro, and Ngapa. The trip was made possible by the support of Mark Saul of Swala Gem Traders (Arusha, Tanzania), Tanzanian gem broker Justin Mmbaga, and several regional mining officers. We found that the most active colored gemstone mining area is still Merelani, which produces tanzanite and green grossular garnet. Ruby and sapphire output has been relatively low since the 2009 discovery of the ruby deposit in Montepuez, Mozambique, as confirmed by our Tanzanian sources.

	Tanzanian miners supply stones to licensed brokers, who are allowed to buy and transport gems within the country. These brokers sell to licensed master dealers, who are allowed to export internationally. These master dealers are mainly located in Dar es Salaam and Arusha. While we met Thai and Sri Lankan buyers in Mahenge, Songea, and Tunduru, foreigners must have approval from regional mining officers and possess a proper business visa to visit the deposits. This is particularly enforced in southern Tanzania; around Songea, we met immigration officers who were “hunting for foreigners.”

	Our journey started in Longido, where rubies were discovered about 100 years ago (D. Dirlam et al., “Gem wealth of Tanzania,” Summer 1992 G&G, pp. 80−102). The main operation in the Longido area is the Mundarara ruby mine, currently Tanzania’s largest, with a workforce of 78 people. The gems are extracted from an underground tunnel about 200 meters deep crossed by several horizontal tunnels that host most of the production. The mine yields ruby in zoisite (suitable for carving), as well as some cabochon- and facet-grade material of a very deep red color. The color is reminiscent of rubies from Mozambique.

	We continued to the Umba River, where Tanzanian sapphire production began after World War II and a ruby-bearing area was discovered by Georges “Papas” Papaeliopoulos in the 1950s (again, see Dirlam et al., 1992). The situation has changed significantly since author VP visited in 2005 and 2009. At the time there was a dispute between the company working the deposit, called “Amazon,” and local communities. The dispute ended with the government revoking Amazon’s license. During our 2016 expedition, we witnessed about 40 small-scale local miners using hand tools to work the primary deposit discovered by Papaeliopoulos, as well as secondary deposits scattered along the banks of the Umba. Most of the production is traded each evening around the Mississippi Hotel in Umba.

	In the Kilindi area, about halfway between Umba and Winza, a new ruby deposit has been discovered near the Maasai village of Loolera. This site, located atop a hill, produces gems very similar to those found near Winza in 2007. We visited the area with the support of the village leader, who said the first rubies were found about 10 years ago, but the quality of the stones was low. A few miners were working the deposit sporadically using hand tools. But in April 2016, some good-quality material was found in amphibole matrix, attracting considerable interest. About 25 mining licenses were issued during the summer of 2016, but there is a sense that the area is under the control of a few major players.

	The deposit where the first rubies at Loolera were found is owned by a miner called Dr. Ozu. The mining pit appeared to be about 90 meters deep, but we could not inspect the tunnel as Dr. Ozu was not present. We studied the entrance and looked through the tailings near the pit. In these rejects we found many small fragments of rubies associated with garnets, amphibole, mica, and feldspar. Although the material we saw resembled Winza ruby, the stones contained minute particles that gave them a milky aspect.

	Our next stop was Winza, where an important gem rush occurred in 2007−2008 (D. Schwarz et al., “Rubies and sapphires from Winza, central Tanzania,” Winter 2008 G&G, pp. 322−347; V. Pardieu, “The Winza ruby and sapphire mining area, Mpwapwa district, Dodoma province, Tanzania,” www.fieldgemology.org, 2009). The main mining area at Mtakanini was nearly deserted. An old rusted washing plant was visible, but due to mechanical problems it had not washed any stones in more than a year. We estimated that a handful of people were still mining around Mtakanini, mainly at primary deposits in underground tunnels, some of which were over 100 meters deep. Working conditions are difficult, as the rock is hard and the tunnels are prone to flooding. We learned that several brief ruby rushes occurred nearby at Godegode, Makutop, Magaseni, Singonali, and Berega. In Morogoro Province, two ruby and spinel mining areas have been exploited since the 1980s. One is located just east of Morogoro in the Uluguru Mountains, and the second is about 150 km south near Mahenge. Most of the gem trade in the Uluguru Mountain region is in Mkuyuni, while the mining takes place near Matombo, Ngongolo, Mwaraze, and Kibuko. In Matombo we witnessed about 30 people retrieving pink spinel and rubies from a secondary deposit near Kiswila. Near Ngongolo, we visited four small-scale operations where locals with hand tools were mining small rubies in marble associated with pyrite, graphite, and mica.

	Near Kibuko, a new pink sapphire deposit was worked by about 10 miners on a site owned by Luciano Kipanzi, who took over the area in 2015. Pink sapphires up to 100 carats are associated with carbonates and pyrite in a primary deposit (figure 2). Most of the stones were the milky “geuda” type, but there was some transparent facet-grade material with very fine crystallization. The mine had evidently yielded about 20 kg of sapphire, from cabochon- to facet-grade, during the previous six months. Nearby, three groups of small-scale miners were uncovering a limited amount of similar stones from secondary deposits.

Figure 2. Pink sapphires from the new deposit near Kibuko. Photo by Vincent Pardieu/GIA.

	The Mahenge district, known for spinel and ruby, is the second most active gemstone mining area in Tanzania. Recent discoveries of graphite near Ipanko and garnet near Lutela (the latter in February 2016) have kindled interest in the area. The new alluvial deposit produces an interesting range of attractive garnets (figure 3), from light “champagne” to deeper saturated rhodolite, including some color-shifting stones. We saw some clean stones weighing up to 20 ct and heard about others as large as 60 ct. About 100 miners were still working the alluvial deposit. Activity was already slowing; we were told that a few months earlier, up to 300 miners were in the valley. This secondary deposit is rapidly depleting, and so far no primary deposit has been located.

Figure 3. This garnet was mined from the new deposit in Lutela, Tanzania. Photo by Vincent Pardieu/GIA.

	Ipanko is still the main spinel deposit in the region. Author VP noticed that the pits were much larger than in 2012, meaning that the area had been mined since then. Nevertheless, the activity seemed slow compared to 2012: Several excavators were working secondary deposits, whereas small-scale miners once worked individual plots, called “boxes” by the locals. The nearby primary spinel deposit was still active, with about 400 people mining red spinel and only a few working on rubies. We then visited several small-scale ruby deposits along the Lukande River, including three operations working either primary or secondary deposits. As in the Uluguru Mountains, the rubies from these areas come from marble-type deposits. We saw about 50 miners working around Lukande, Kwam Somali, Mayote, Chipa, Ibogoma, Gombe, and Kitonga during the dry season, retrieving cabochon-grade rubies along with smaller facet-grade material. During the rainy season, these workers focus on gold mining or farming.

	Our last visit was the region around Songea and Tunduru, where sapphire production began in the 1990s. The Songea deposit, discovered in 1992, was quite productive until the discovery of fine blue, yellow, and pink sapphires near Tunduru in 1994. The deposit was nearly inactive until the early 2000s, when the newly developed beryllium diffusion treatment was able to turn Songea’s muddy green and brownish purple stones into attractive yellow to orange sapphires. In Songea, we heard of a new discovery at Amani Makoro, close to the old diggings around Ngembambili and Masuguru. In Amani Makoro, we witnessed about 200 miners in a swampy area using hand tools. The aspect and quality of the stones was similar to those from Ngembambili and Masuguru. Overall, about 300 people are still mining or trading gems around Songea. According to the regional mining officer, nine Thai merchants are registered buyers here. Songea still seems to be Tanzania’s most active sapphire mining area.

	The region east of Tunduru, located along the Muhuwesi, Lumesule, and Ruvuma rivers and up through Ngapa and Kitowelo, is known to produce blue, yellow, green, pink, and purple sapphires, and rarely rubies. The deposits, discovered by Swiss gem merchant Werner Spaltenstein in 1994, were very active until 1999, when buyers left Tunduru for the newly discovered sapphire deposits of Ilakaka, Madagascar.

	A paved road linking Tunduru to the coast and then Songea should be finished in 2017, making these areas much less isolated. Around Tunduru, a new environmental law that forbids mining within 60 meters of a stream or a river is creating issues, as most of the mining there takes place in riverbeds. Last year Mr. Spaltenstein had to stop his mechanized operation because of that law, though local authorities seem to be more tolerant of small-scale miners. While the area is much less active than when VP visited in 2005 and 2008, we estimate that about 400 to 500 miners are working around Tunduru. In the town, we found 10 Sri Lankan and three Thai buying offices. In the main gem-producing area there was a small rush in Ngapa, near Kitowelo and the area known as the “DSM Box” (figure 4). We were told the area produces some good blue, pink, and purple sapphire rough weighing up to 50 ct; fine sapphire of this size was previously unknown in Tunduru. The second most active place was Muhuwesi, where several groups of small-scale miners are reportedly working.

Figure 4. This blue sapphire rough, weighing about 7 ct, is from the new deposit at Ngapa, near Tunduru. Photo by Vincent Pardieu/GIA.

	The post-2009 downturn of Tanzania’s ruby and sapphire mining was not unexpected, because many of the corundum discoveries triggered rushes that were exploited for short-term gain. Tanzania also faces competition from the world-class ruby deposit in Montepuez. Nevertheless, recent colored stone discoveries point to the vast potential of gem mining in Tanzania. @chapter:23 @chapter:0 @chapter:23


# Publication Year: 2021
# Title: Rainbow Graining in Diamond
# Abstract: This yellow diamond displayed a remarkable example of rainbow graining that appears and disappears as the stone is tilted. Photomicrograph by Nathan Renfro; field of view 4.64 mm.

One of the more subtle inclusion scenes gemologists sometimes observe in natural diamonds is the presence of crystallographically oriented structural defects known as “internal graining.” Often resulting from octahedral and cubic growth sectors of a diamond crystal competing for space during growth, these structural disconformities present as colorless, whitish, reflective, colored, and rarely rainbow varieties of graining (J.I. Koivula, The Microworld of Diamonds, Gemworld International, Northbrook, Illinois, 2000). Colorless graining is the most common type encountered, while whitish graining is somewhat less common and shows, as the name implies, a hazy white appearance in the immediate area of the structural defect zone. Colored graining often occurs when plastic deformation along the cleavage direction results in color causing defects in the diamond crystal lattice. If the defects are numerous enough, they can impart a bodycolor, which in the case of pink and red diamonds greatly enhances their value. Reflective graining occurs as a result of excess strain buildup from the crystallographic defects. The diamond’s accumulated strain is released by separating along cleavage planes, leaving a reflective, mirror-like separation as the most obvious characteristic of this type of graining. The rarest of all types is known as “rainbow graining.” In these remarkable stones, the structural defects in the diamond’s crystal lattice are ordered layers, which act as a diffraction grating to reveal a vibrant display of spectra colors (Summer 2007 Lab Notes, p. 155).

	Rainbow Graining in Diamond

Recently, the author had the opportunity to examine a spectacular example of a yellow diamond containing prominent rainbow graining (see video above). When the stone was rocked and tilted, the rainbow colors would appear and disappear. The elusive beauty of this type of graining and the difficulty with which it is observed make this type of graining a rare and welcome sight in natural gem diamonds. @chapter:29 @chapter:1 @chapter:29


# Publication Year: 1996
# Title: Gemological Investigation of a New Type of Russian Hydrothermal Synthetic Emerald
# Abstract: Tairus, in Novosibirsk, has produced yet another new type of Russian hydrothermal synthetic emerald, now being marketed in Bangkok. Examination of eight faceted samples revealed that, with the exception of certain characteristic inclusions, the basic gemological properties shown by this new synthetic are essentially the same as those encountered in other hydrothermally grown synthetic emeralds and some natural emeralds. If the characteristic inclusions are not present, distinctive spectral characteristics in both the mid-and near-infrared regions of the spectrum will serve to separate these synthetic emeralds from their natural counterparts. @chapter:10 @chapter:0 @chapter:10


# Publication Year: -
# Title: How to Photograph Gems & Jewelry
# Abstract: With the right techniques and accessories you can take high-quality photos of gems and jewelry using your mobile device’s high-resolution camera

	Being able to take great photos of gems and jewelry is a valuable skill – whether you’re in retail sales, gem identification, wholesale, design, or do it for a hobby. And it will only become more important as social media and e-commerce play an increasingly central role in our lives.

	A state-of-the-art digital SLR or mirrorless camera is usually best for the task. But a smartphone or other similar handheld device with a high resolution camera (8+ megapixels) can take professional-looking pictures using the right techniques and accessories. We offer some tips, no matter the camera you are using, plus some smartphone-specific advice.

	Before You Begin

		Use a tripod to stabilize your camera. If one is not available, make sure your smartphone is on a stable surface when taking photos. Make sure your object is in focus. A tap on the screen should do this for many smartphones.

		Use a wireless shutter release to take the photo without touching the screen. Physically touching your mobile device screen could shake it and result in a blurry picture. These devices connect through a Bluetooth connection.

		Clean your jewelry: Your smartphone’s high-resolution camera will capture dust, marks and scratches. Fingerprints, which are often unseen by the naked eye, can also mar beautiful jewelry. A soft, clean jewelry cloth is ideal for getting your pieces camera-ready. Handle the object with clean cotton gloves.

		Depending on your subject, you may benefit from a macro lens that enables extreme close-up photography of small items or minute features. Clip-on macro lenses are available for smartphones from a variety of manufacturers for Apple and Android devices. ōlloclip macro is a good one and is portable.

	Amazon.com and Photojojo.com are great resources for smartphone camera gadgets and lenses.

Choose appropriate backgrounds, as it can affect the appearance of metals, diamonds and light-colored gemstones.

When to use a black background: Light-toned pieces often look better on darker backgrounds because contrast adds drama. It also calls attention to jewelry.

When to use a white background: Poorly cut gems can appear more attractive on light backgrounds. White backgrounds also bounce light back at the subject matter, which can minimize distracting shadows.

		A clean white piece of paper, plastic or tile used as a background can keep the picture uncluttered and help achieve a correct color balance.

	Correct lighting and positioning of a gem or piece of jewelry are two techniques that will help you take great digital photos. The first ensures a successful photograph. The second makes a picture interesting – or even compelling.

This andalusite from Minas Gerais, Brazil weighs 2.87 ct. This image (left) shows direct lighting, which is not ideal for bringing out the transparent gemstone's rich pleochroic colors. Instead, the direct lighting seems to darken the stone and creates "hot spots" along some of the facets. Diffused lighting for the gem, helps bring out the andalusite's pleochroic colors (right). Photo by Robert Weldon/GIA

	Lighting

		Use a single color temperature of light: Try to avoid environments that have mixed lighting – like fluorescent, incandescent and daylight. Find a location that has one kind of lighting, and use it as your only source.

		Direct lighting works best for ornamental materials, and occasionally to provoke dispersion in a transparent gem. It is also sometimes used to bring out gemstone phenomena such as asterism (a star effect) or chatoyancy (a cat’s eye effect).

		To exhibit a gemstone’s best color, lighting should be diffused rather than direct. Diffused lighting scatters light, softens shadows and provides uniform lighting. This can be achieved by placing a translucent white glass, plastic, or cloth between the light source and the gem. Tracing paper, onionskin paper or translucent vellum are also good choices to scatter light, cast soft shadows, and bring out a gemstone’s best color.

		A mix of direct and diffused lighting can add drama to a photograph by adding some sparkle or dispersion to a transparent gem, while also bringing out its finest colors.

		When photographing highly polished metal, the shiny surfaces can be challenging, especially with direct lighting. Diffused lighting often works well to exhibit soft tonal gradients in the metals, and to highlight the designed metalwork.

Add cards or reflectors to your stage to help bounce light towards your subject. You can use an envelope or card stock. Brooch designed by Paula Crevoshay. Courtesy: GIA collection

	Positioning

		Gemstones are cut and fashioned to show their best colors when looking straight down at them, perpendicular to the table of the gem. If the gems are cut as cabochons (a gem with a rounded, unfaceted, polished surface) and have asterism (a six-rayed star created when light hits inclusions in the gemstone), it is best to light them in a way that centers the star in the middle of the stone. With carved materials, there is much more latitude in the direction in which a piece can be photographed, but even then it is important to determine the artist’s principal objective. Talking to the cutter or designer is important to have an idea of their perspective.

		When positioning jewelry, it is important to consider the jewel’s salient characteristics: is a diamond or a colored gemstone the centerpiece? Can you observe the designer’s intentions through the way you position the jewel, and the camera relative to it?

		The camera angle may also be used as a tool: photographing “straight on” is important for documentary style photographs. To captivate a viewer’s imagination, the subject may be turned, or the camera angle skewed, to obtain dramatic results.

This blue topaz, briolette sapphire, and diamond ring looks good in all directions. The human eye likes symmetry, so the "straight-on" look works (left). But a more elevated and angled view of the ring (right) shows more of the center stone, accentuates the unusual double-shank design, and gives the viewer a more holistic view of it. Photo by Robert Weldon/GIA

View Gallery

	Process Your Image

	Do this before you finish your photo shoot. Apps on your phone can crop, help adjust color balance, and get a gemstone or piece of jewelry to photograph the way it really looks. This will avoid colorcasts (unwanted tints in the image), and will help capture an accurate image of the object.

Recommended Apps with advanced photo processing features:

Camera+: Great for sharpening photos over the regular edit tool

Instafit: To retro-fit photos with white borders for a more artsy look

PicTapGo: For easy editing and color correction

645 Pro Mk III: Provides a little more control over ISO, WB, filters, etc.

Retouch: To delete any distracting elements

iWatermark: To watermark all your images

View Gallery

	Taking great pictures is like learning any skill: the more you do it, the better you’ll get. So the next time you set up for a photo shoot, use our tips. The results will be worth it. @chapter:33 @chapter:2 @chapter:33


# Publication Year: -
# Title: Zircon Care and Cleaning Guide
# Abstract: Zircon ranks 6 to 7.5 on the Mohs hardness scale.

Hardness and toughness
Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with which one mineral can be scratched by another. But the Mohs scale is deceptive. The steps between the minerals are not evenly spaced. For example, diamond is only one number away, but it’s many times harder than gems in the corundum family.

Zircon is rated 6 to 7.5 on the Mohs scale. It has fair to good toughness. While zircon is not as hard or tough as a stone like sapphire, it can still be worn in all types of jewelry as long as proper care is given to avoid rough wearing or hard blows. Also, zircon can be brittle, so it should be worn and stored in a manner that avoids hard rubbing against other materials.

Stability
Zircon is generally stable when exposed to light, but some heat-treated stones might revert back to their original colors (usually light brown) after prolonged exposure to bright light. Heat can alter the color of some zircon. Zircon is stable when exposed to chemicals.

Cleaning
Warm, soapy water is recommended for cleaning zircon. Ultrasonic and steam cleaners are not recommended for cleaning this gem.

	Zircon can be worn and enjoyed for its beauty with a few precautions to avoid rough wear
	that could cause abrasions. - Courtesy Sarah & Leonard Friedman
Treatment concerns
Zircon is commonly heat-treated to produce blue and colorless varieties. As with any transparent gemstone, zircon can be fracture-filled to improve apparent clarity, but this treatment is rarely applied to this gem. @chapter:18 @chapter:1 @chapter:18


# Publication Year: 2023
# Title: GIA Library Wins Exhibit Award at TGMS
# Abstract: The GIA Library’s award-winning exhibit on mercury-free mining at the Tucson Gem and Mineral Show. Photo by Chris Rogers.
GIA’s Richard T. Liddicoat Gemological Library and Information Center was awarded the Betty Clayton Gibson Memorial Trophy for Best Museum Exhibit for 2023 at the Tucson Gem and Mineral Show. The winning exhibit illustrated the importance of mercury-free gold mining (see above). Historically, mercury has been used in artisanal and small-scale gold mining because of its ability to bond with gold to form an amalgam, but its high toxicity and negative effects on humans and wildlife have led to increased emphasis on mercury-free options for mining gold.
The exhibit featured a traditional wooden bowl used for gold panning, along with many of the library’s books on ecological jewelry and responsible and sustainable mining and jewelry practices.
“This exhibit illustrates how mercury-free gold mining can have positive long-term implications for both gold miners and the environment,” said library director Robert Weldon. He noted that among all the deserving exhibits displayed at TGMS, the GIA Library’s stood out due to the importance of responsible mining and sustainability in the industry.
In 2021, GIA provided a grant to Mercury Free Mining (MFM) and the Alliance for Responsible Mining (ARM). New methods for concentrating gold continue to be explored and tested with the goal of significantly reducing, or even eliminating, the use of mercury in gold mining. @chapter:38 @chapter:3 @chapter:38


# Publication Year: 2015
# Title: Strong Pinkish Purple Freshwater Bead-Cultured Pearls
# Abstract: Figure 1. This necklace of freshwater bead-cultured pearls from China displays strong pinkish purple hues with orient. Photo by Sood Oil (Judy) Chia.

Freshwater cultured pearls are known for their wide range of attractive colors, including different combinations of white, orange, pink, and purple hues (S. Akamatsu et al., “The current status of Chinese freshwater cultured pearls,” Summer 2001 G&G, pp. 96–113). Jack Lynch of Sea Hunt Pearls (San Francisco) recently submitted a necklace consisting of 33 strong pinkish purple near-round pearls, ranging from 11.90 to 13.85 mm in diameter (figure 1), to GIA’s New York laboratory. The unusually intense color and large size of the pearls immediately drew our attention. Mr. Lynch indicated that the pearls were farmed in both the Hunan and Hubei provinces of China, over a period of three and a half to four years.

Figure 2. Real-time X-ray microradiography analysis revealed the round shell bead
nucleus used to culture each of the pearls. Photo by Yixin (Jessie) Zhou.
Real-time X-ray microradiography (RTX) analysis revealed that all of the pearls in the necklace were bead cultured and had relatively thick nacre (figure 2). Energy-dispersive X-ray fluorescence (EDXRF) analysis detected a high concentration of manganese, confirming that these pearls were grown in a freshwater environment. Furthermore, Raman spectroscopy verified that their color was natural, with two strong peaks around 1130 and 1510 cm–1 associated with natural polyenic pigments found under 514 nm laser excitation (figure 3), consistent with previous studies (S. Karampelas et al., “Role of polyenes in the coloration of cultured freshwater pearls,” European Journal of Mineralogy, Vol. 21, 2009, pp. 85–97).

Figure 3. Raman spectroscopic analysis on the pearl’s surface showed two natural
polyenic pigment peaks at 1130 and 1510 cm–1.
Earlier Chinese production with large beads resulted in a high mortality rate. We continue to see larger bead-nucleated freshwater cultured pearls, so it appears that the process has greatly improved, either through better techniques or hybrid mollusks (D. Fiske et al., “Continuity and change in Chinese freshwater pearl culture.” Summer 2007 G&G, pp. 138–145). Pearls with larger size, a near-round shape, and intense coloration are highly sought after and more valuable than traditional products. The owner’s inquiries revealed that the pearls were formed under an extremely controlled environment and culturing procedures in mussels that produce the material marketed as “Edison pearls.” This necklace proves that current culturing techniques can achieve a wide range of vibrant hues, providing interesting and unique products for the market. @chapter:11 @chapter:4 @chapter:11


# Publication Year: -
# Title: GIA’s Knowledge Sessions: A New Way to Share Gemological Information
# Abstract: Robert Weldon talked about this photo during the “Behind the Scenes: Untold Stories from GIA Field Gemology Expeditions” webinar. The photograph shows a model of Campbell Bridges famous tree-house — glowing with light at night — in Kenya. The original tree house, near Tsavo National Park, is the place where he discovered green garnet or tsavorite. Photo by Robert Weldon

Video calls and webinars have taken the world by storm ever since the coronavirus sent everyone home for safety. They are an easy way to stay connected with family and friends and many — including GIA — are using them to share knowledge.

GIA’s Knowledge Sessions began in early April and since then, they have covered a variety of gemological research topics, including pearls, laboratory-grown diamonds, field gemology and jade auctions. The hour-long sessions provide an opportunity for researchers and subject matter experts to stay connected with the other researchers, retailers, designers and other people who are excited to learn more about the world of gems and the jewelry industry, in a friendly, more casual format.

“Our researchers normally speak at seminars and conferences, but now that we can’t travel as a result of the pandemic, we saw there was another way to connect with the research community to share our information,” says Kellie Giordano, GIA senior manager of content marketing and the moderator of the web sessions. “Our researchers are so talented and great at communicating all of this complex research in an accessible way. The webinars evolved into a resource for the entire gem and jewelry industry to understand how they might apply the research GIA is doing every single day into their work — as a retailer, wholesaler or whatever stage of the supply chain they are in.”

Dr. Mike Breeding, who presented “Laboratory-Grown Diamonds: Updates and Identification,” says the webinars speak to GIA’s mission to protect the public and giving them the information they need to thrive in their area of interest.

“Many trade members can’t afford the time or money to attend conferences or pay for on-campus seminars, so this is a fantastic mechanism for us to get important information to them to help in their daily challenges in the gem industry,” he says. “People are already excited about gems, but these types of informative webinars really give them even more to be excited about and empowers them with knowledge.”

The number of people who sign up and attend each session is surprising, but gratifying, to the presenters. To-date, there have been more than 48,000 registrants and more than 21,000 attendees in 21 presentations and more than 65,000 views (with a total of more than 10,000 hours watched) on YouTube, where all of the sessions are posted.

“The webinars are a fantastic way to reach all corners of the globe, even if someone has to get up super-early, or stay up super-late to see it,” said Robert Weldon, director of the Richard T. Liddicoat Library and Information Center, who presented “Behind the Scenes: Untold Stories from GIA Field Gemology Expeditions,” with Wim Vertriest, supervisor of field gemology and Dr. Aaron Palke, senior manager of research. “As evidenced on several of the talks, thousands of people have tuned in at one time.”

The webinars are held weekly in English, but several have been presented in Mandarin, such as “An Exclusive View of the World’s Biggest Jade Auction,” by Dr. Tao Hsu, director of global development, “The Fascinating World of Pearls and Shells,” by Dr. Chunhui Zhou, manager of pearl identification, “Laboratory-Grown Diamonds from China,” by Dr. Wuyi Wang, vice president of research and development, and “Advanced Analytical Techniques,” by Ziyin Sun, research associate.

Wang said the webinars are an effective way to share gemological research findings with a large number of people at a time. “It is impossible to attract this many people to attend any on-site presentation,” he says. “We should sustain this platform.”

A New Format for a New Gem and Jewelry World
GIA Knowledge Sessions cover a broad spectrum of topics, from some of the more popular gemstones — diamonds, pearls and rubies — to lesser-known aspects of gem exploration and research tools.
“We’re really looking to provide a wide range of topics. We have this wealth of knowledge and we want to use these webinars to deliver as much of it as we can,” Giordano says.

Presenting the information in a webinar format, as opposed to a conference setting, was a little strange for the researchers at first, but they quickly adjusted.
“I was pleasantly surprised at how easy it was to present the webinar,” Breeding says. “At first it was a bit weird to not see the people as I talked, but as it went on, it was very relaxed and easy to discuss the slides and information.”
Dr. Zhou says that as he sat alone in a room talking in front of the screen, he wondered what the audiences were doing at the moment in different parts of the world, but that it was less stressful than presenting in person at a conference.
“It is a great way to share information and connect with the trade and public during this extraordinary period of time,” he says. “The technology advances make it easy for anybody to join from all over the world and they can even watch a recording after the talk.”
The benefits of an online presentation — no need to travel, watching from anywhere in the world and on-demand viewing — also include an easy-to-follow format for the presenter and the viewer.
“I enjoy the 45-50 minute talking time slot we get. This allows you to really tell a story, but at the same time forces you to bring structure to it. It’s always easier to see or listen to someone explain it thoroughly,” says Vertriest, who also presented “Rubies: Connecting Sources, Treatment and Science” and “Geology 101 for Gemologists: The Natural Processes that Form Colored Gemstones.”
“A good presentation takes you by the hand and leads you through all the challenging science that might appear overwhelming in written format,” he says. “Since presentations are very visual, the information can also be presented in a more intuitive way.”
It also enables the audience to ask questions through a chat feature during the presentation and at the end of it.
“I could see the questions pop up on the side as I went and it was difficult to not try to answer them immediately,” Breeding says. “I found myself remembering to include small details that I might have otherwise skipped because I knew someone was wondering about it.”
The questions also indicated that there were both insiders in the gem trade and general public listening to our talks, Chunhui says.
“It was also surprising to see the range of questions. Everyone has a different perspective and it is interesting to see what details people pick up on,” Smith says.
Nick Sturman, senior manager of identification, who presented the “Fascinating World of Pearls and Shells,” suggested that extra dialogue specific points can be raised on GIA's Gems & Gemology Facebook page. “So far that hasn't happened much but a few people have taken the opportunity to raise a point,” he says.
“I have been so pleasantly surprised by the participation,” Giordano says. “We get so many great, high-quality questions and there is so much curiosity around each topic.”
She said that post-webinar surveys indicate that 95% of participants agree or strongly agree that the topic was valuable, 95% rate the session as excellent or good, and 100% want to attend another GIA Knowledge Session.
Some of the anonymous comments from the survey:

 “I really appreciate GIA producing these webinars during the pandemic times, they’re interesting and keep us connected.

“It is truly amazing how the webinars help to connect the theoretical knowledge [that] is acquired during the self-study to a more practical approach. Already looking for the next one!”
“What really impressed me, along with the expertise, was the friendly, informal presentation. Fun!”

GIA’s Digital Transformation is Underway
“Knowledge Sessions are a great example of how we are using modern technology to connect with our GIA community,” says Mark Buntz, senior vice president and chief marketing officer. “We want to make it easy for researchers, students and alumni to access our expertise and spark an even greater interest in gems and jewelry around the world.”

Dr. Hsu agrees that webinars and other digital tools are an effective way to share many different type of information - not just that limited to gemological research. “Educational information and even retailer support type of information can all be shared this way,” she says.
She presented “GIA Research - Not Just for Scientists,” a behind-the-scenes look on how GIA designs its world-respected curriculum.

GIA is also making other outreach efforts online, including a GemFest on the “Geographic Origin Determination of Ruby,” which was presented in Japanese from Tokyo and the 115th Gemstone Gathering, a popular event in Thailand, on “Precision Cut: How, Why and When?” by Victor Tuzlukov, a well-known master lapidary artist.

Above all, says Dr. Evan Smith, who presented the first GIA Knowledge Session – “The Unique Story of Natural Diamond” — in early April, the webinars help showcase some of the things that distinguish GIA from other gem labs.

Dr. Evan Smith showed this image of a super-large faceted diamond in “The Unique Story of Natural Diamond” webinar. Photo by Ulrika D’Haenens-Johansson
“Some people may know GIA best as an issuer of certificates and accreditations, but its mission is much broader,” he says. “The Knowledge Sessions shed light on the diverse nature of work that goes on behind the scenes at GIA, and our commitment to re-investing into research and education.”
Go to GIA Knowledge Sessions to register for an upcoming webinar or watch one that has already been presented. @chapter:38 @chapter:2 @chapter:38


# Publication Year: 2021
# Title: Chanthaburi:The city of gem_2
# Abstract: In the areas of Khao Phloi Waen and Khao Wao, famous gemstones have been discovered, making Chanthaburi known globally as a respected hub in the gem-collecting community. Its rich natural resources and geological significance continue to support ongoing gem mining activities to this day. @chapter:40 @chapter:2 @chapter:40


# Publication Year: 2019
# Title: Grossular Garnet Crystals in Demantoid Garnet
# Abstract: Figure 1. A cluster of transparent octahedral crystals observed in a yellowish green demantoid garnet. Photomicrograph by Ungkhana Atikarnsakul; field of view 1.2 mm.

Demantoid, the green variety of andradite garnet, is a rare gemstone. It typically possesses high dispersion and diamond-like luster, which is often partly masked by the green and yellow-green bodycolors. Variations in the color of demantoid garnet are generally caused by traces of chromium (Cr3+), ferric iron (Fe3+), Fe2+-Ti4+ intervalence charge transfer, and Fe2+-Fe3+ interactions (G. Giuliani et al., “Gem andradite garnet deposits demantoid variety,” InColor, No. 36, Summer 2017, pp. 28–39).
Recently, GIA’s Bangkok laboratory received a 4.47 ct yellowish green gemstone for identification. Standard gemological testing, including a refractive index over the limits of the refractometer and a specific gravity of 3.86, and Raman spectroscopy identified it as demantoid garnet. Microscopic examination revealed strong internal graining, fingerprints, and particles mixed with short needles. Interestingly, it also exhibited transparent octahedral crystals at the crown (figure 1). Some of them reached the surface and had a different luster from the host material. Close examination showed that the crystals contained two different luster areas, which also distinguished them from the host demantoid (figures 2 and 3).

Figure 2. Some of the transparent octahedral crystals reached the surface of the demantoid. Photomicrograph by Ungkhana Atikarnsakul; field of view 2.0 mm.

Figure 3. LA-ICP-MS was performed on three different areas: the host demantoid (spot 1), the outer area of the included crystal (spot 2), and the inner area of the included crystal (spot 3). The blue dashed line shows the separation between the demantoid area and the outer area of the inclusion. The yellow dashed line separates the outer and inner areas of the inclusion. Photomicrograph by Ungkhana Atikarnsakul; field of view 1.0 mm.
Raman spectroscopy was performed on the three different areas to identify the materials. The Raman spectra of the two areas of the crystals were similar to that of the host, matching with andradite garnet. Garnet species typically possess similar physical properties and crystal forms, but differ in chemical composition. For example, andradite is a calcium-iron garnet with the formula Ca3Fe2(SiO4)3, whereas grossular is a calcium-aluminum garnet with the formula Ca3Al2(SiO4)3. Those two garnet species are in the same isomorphous series and therefore have the same general chemical formula, but differ only in containing Fe or Al. Due to their similar Raman spectra, chemical analysis is better suited to separate the species of garnet.
In this case, laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) was used to compare the chemical composition of the demantoid against that of the surface-reaching inclusions. Spot 1 was on the host material, spot 2 on the outer area of the crystal inclusion, and spot 3 on the inner area of the crystal (figure 3).

Surprisingly, the three spot areas exhibited different chemical compositions, especially between the host demantoid area and the inner area of the crystal. This indicated that the crystal inclusion was from a garnet species other than andradite. Table 1 shows the chemical composition of the three spot areas, provided first in parts per million by weight (ppmw) units, followed by wt.% oxides of elements, and then as recalculated cations normalized to 12 oxygen atoms. Spot 1 (the demantoid) contained significantly more Fe than Al, whereas spots 2 and 3 of the crystal inclusion contained both elements. Spot 2 contained a higher concentration of Fe than Al, and the calculation showed a mix of two garnet species. It is possible that the detection area partly included the host material. Spot 3 contained a higher Al concentration than Fe (a 75.36% match with grossular).
Many types of solid inclusions are found in demantoid garnet, such as chromite, apatite, and diopside. From the results obtained here, it is interesting that solid inclusions of a different garnet species—grossular, in this case—can also be trapped in demantoid. @chapter:3 @chapter:0 @chapter:3


# Publication Year: 1984
# Title: The Santa Terezinha De Goias Emerald Deposit
# Abstract: The Santa Terezinha de Goias emerald deposit, currently the most important source of emeralds in Brazil, lies northwest of Brasilia, in the State of Goias. The emeralds, most of which are stones of a carat or less, occur in a talc schist layer intersected by pegmatite. The emeralds are recovered by independent miners via trenches, pits, and tunnels at two prospects: Trecho Novo and Trecho Velho. The grade of the ore is: 1 to 6 parts of emeralds to 10,000 parts of ore. The density of the gems is 2.70; the refractive indexes are 1.580 and 1.588, with greenish dark blue/yellowish pale green pleochroism. The spectrum is typical, with two strong lines and two partial absorption bands; there is no fluorescence; pyrite and chromite are the most typical inclusions, with calcite crystals present in minor amounts. @chapter:2 @chapter:0 @chapter:2


# Publication Year: 1995
# Title: History of Pearling in La Paz Bay, South Baja California
# Abstract: The history of Baja California has been closely tied to the exploitation of pearls since the 16th century. Using rudimentary diving techniques for most of this era, European and Mexican entrepreneurs recovered vast amounts of fine, dark pearls from this region. However, years of overfishing inevitably led to decades when the oyster beds were all but barren. Introduction of the diving suit in the 19th century extended the depth of the beds that could be fished, but overexploitation continued largely unchecked. Cultivation of the pearl oyster Pinctada mazatlanica by Gaston Vives, between 1903 and 1914, greatly slowed exhaustion of the natural stock. His company, CCCP, represented the world's first large-scale cultivation of pearl oysters, and many of Vives's discoveries are used today in renewed pearl-oyster cultivation and pearl-culturing activities in Baja California. @chapter:53 @chapter:4 @chapter:53


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

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

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

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

Abstracted by Edward R. Blomgren @chapter:22 @chapter:1 @chapter:22


# Publication Year: 2012
# Title: Spectral Characteristics of Natural-Color Saltwater Cultured Pearls from Pinctada Maxima
# Abstract: Natural-color saltwater cultured pearls (SWCPs) from Pinctada maxima were studied using UV-Vis-NIR and PL spectroscopy to better understand the mechanisms of their coloration and to separate them from other SWCPs with similar natural colors. Several spectral features were observed, suggesting that the samples’ bodycolor is due to a mixture of pigments. Although similar spectral characteristics are observed in SWCPs from Pteria sterna and Pinctada margaritifera, subtle differences permit the identification of the host mollusk. @chapter:11 @chapter:4 @chapter:11


# Publication Year: -
# Title: Smaller 2018 Basel Fair is Still Biggest Rare Gem Showcase
# Abstract: The 2018 edition of Baselworld had half the number of exhibitors of last year’s fair. Management vows to retrench after this major exodus. Photo Courtesy of Baselworld

Business at the scaled-down Baselworld 2018 Show (March 22-27) was spotty with some jewelry brands and gem dealers posting respectable sales, while others found trading to be very slow.

The show was half the size (650 exhibitors) of last year’s and less than 40% of the size of the show at its peak in 2014. Most of the departures were watch brands (Movado, by far the largest exhibitor at the show, was not present this year), jewelry design houses and nearly all of the manufacturers of jewelry manufacturing equipment. The number of gem dealers, however, declined very slightly.

The show was hemorrhaging exhibitors for several years because of the very high costs – more than double other trade shows – and the eight-day-long length of the show, which increased costs even further. This year, the Baselworld management reduced the length of the show by two days, and the price accordingly.

An invisibly-set ruby and diamond bow brooch by Graff. Photo by Russell Shor/GIA

Sylvie Ritter, managing director for Baselworld, said next year’s fair will be one week and there will be some “new exhibition formats” for smaller exhibitors to help add value to their presence. She did not elaborate, saying these details will be announced in the fall.

Exhibitors in the jewelry brands sections who had a large existing clientele generally did fairly well because high-end retailers still see the luxury market continuing to recover in Europe, the U.S. and China. Most were buying for stock and adding a small number of distinctive, costly pieces they believed they could move fairly quickly. There was very little new business at the show, however, so exhibitors who did not have a regular clientele found trading very slow, despite the fact that half of their competitors were no longer exhibiting.

A graduated color cabochon tourmaline necklace from Paul Wild, Kirschweiler, Germany, of 174 stones totaling 730.25 carats. Photo courtesy Paul Wild
HIGHLIGHTS
Among the design trends were black diamonds (lots of black diamonds) and green gemstones – emeralds, tourmalines and peridot. The popular motifs were boughs, bows and blossoms.

The Baselworld gem hall offers perhaps the largest array of extreme top-end gemstones anywhere in the world outside of the auction houses – major fancy colored diamonds, 10-carat-plus colorless diamonds and large rubies, sapphires, emeralds, Paraiba tourmalines and other rare gems. This year’s edition had even more than usual.

Business in this hall was spotty as well, driven largely by other dealers looking for major stones for which they have immediate calls, or speculators who believe prices of certain goods will be increasing.

The Stelle in Flore pair of rings from Pascale Bruni, Vicenza with invisibly-set black, colorless and light brown round diamonds set in 18k gold. Photo courtesy of Pasquale Bruni
Fancy colored diamonds dominated the spotlight in the gem hall, with at least a dozen diamonds from past Argyle pink diamond tenders. Demand, however was strongest for fancy blue diamonds in the intense and vivid grades (without modifying colors) because of a trade sentiment that such stones are now underpriced.

One major dealer noted that “we heard the rumor, raised our prices and these dealers bought them anyway.”

Fancy yellow diamonds also saw a recovery in demand if they had no modifying color, dealers said.

The 910 ct “Lesotho Legend,” the fifth largest diamond ever discovered was mined at Letseng, Lesotho in January. Photo Russell Shor/GIA.
Taché, the Antwerp diamond manufacturer, exhibited the 910 carat rough diamond Lesotho Legend that was mined earlier this year from the Letseng mine in Lesotho. It is the fifth largest diamond ever found, and Taché bought it for $40 million two weeks before the show opened. The company said it will study the diamond for four or five months before beginning the cutting process.

A 110 carat pear shaped diamond from the Nizam of Hyderabad Collection offered by Rare Diamond House of Antwerp. Photo by Russell Shor
The Rare Diamond House of Antwerp displayed a Moghul-era 110 ct-plus D internally flawless, Type IIa pear-shaped diamond that reportedly belonged to the legendary Nizam of Hyderabad, who accumulated one of the largest gem collections in history before it was sold off in the 1970s and 1980s

Oded Mansouri, director of Rare Diamond House, said he acquired the diamond about 18 months ago. “The diamond had been cut in the 1800s and was not completely symmetrical,” he said. “But it was so fiery that when I gave it to the cutter to recut, he told me he would walk out before it would recut this stone.”

A “Mystery Clock” by RCM Gioielli, Valenza Italy. Two marquise cut fancy brown diamonds, 2.33 ct and 1.56 ct, serve as the hour and minute hands. The base, dial and columns were fashioned from one 70 kg piece of rock crystal, said Mirella Francia, a director of the company. The “numbers” total 34.86 carats of round diamonds set in lapis. Rose cut diamonds totaling 10.5 carats are set in 18k gold. Photo courtesy of RCM
M. Vainer of London offered a 4.25 ct Fancy Deep orangy brown diamond that displayed secondary colors of red and yellow in different light sources, and several Argyle diamonds from tender auctions in the 1990s.

“Some of these older Argyle diamonds are being recut because in the years since, they have learned how to draw the best colors from these stones,” explained Richard Vainer, a company partner.

A suite of demantoid garnets by Constantin Wild, of 21 round cuts weighing 28.54 carats total, plus a 3.43 ct center stone; a bracelet of 13 demantoids weighing 15.93 carats and two demantoid center stones over 2.5 carats. Photo by Russell Shor/GIA
Constantin Wild showed a necklace demantoid garnet of 21 round cuts weighing 28.54 carats total, plus a 3.43 ct center stone; a bracelet of 13 demantoids weighing 15.93 carats and two demantoid center stones over 2.5 carats.

“Such stones are very rare over one carat,” Wild noted.

A melo pearl collection from Gem Trade, Lugano containing 15 pearls ranging from 10 carats to 45 carats. Photo by Russell Shor/GIA.
Gemtrade of Lugano, Switzerland offered a 15-piece melo pearl collection ranging from 10 carats to 45 carats, in addition to a number of rarely seen gemstones. @chapter:32 @chapter:3 @chapter:32


# Publication Year: -
# Title: Tourmaline History and Lore
# Abstract: This 376.85-carat tourmaline was carved by O. Hansen, using the colors of the tourmaline as part of the design. - Chip Clark, courtesy Smithsonian Institution, National Museum of Natural History

                      Somewhere in Brazil in the 1500s, a Spanish conquistador washed the dirt from a green tourmaline crystal and confused the vibrant gem with emerald. His confusion lived on until scientists recognized tourmaline as a distinct mineral species in the 1800s. The confusion about the stone’s identity is even reflected in its name, which comes from toramalli, which means “mixed gems” in Sinhalese (a language of Sri Lanka).  It’s a term Dutch merchants applied to the multicolored, water-worn pebbles that miners found in the gem gravels of Ceylon (now Sri Lanka).

It’s easy to understand why people so easily confuse tourmaline with other gems: Very few gems match tourmaline’s dazzling range of colors. From rich reds to pastel pinks and peach colors, intense emerald greens to vivid yellows and deep blues, the breadth of this gem’s color range is unrivalled. Brazilian discoveries in the 1980s and 1990s heightened tourmaline’s appeal by bringing intense new hues to the marketplace.

People have probably used tourmaline as a gem for centuries, but until the development of modern mineralogy, they identified it as some other stone (ruby, sapphire, emerald, and so forth) based on its coloring.

One of the earliest reports of tourmaline in California was in 1892. In the late 1800s, tourmaline became known as an American gem through the efforts of Tiffany gemologist George F. Kunz. He wrote about the tourmaline deposits of Maine and California, and praised the stones they produced.

In spite of its American roots, tourmaline’s biggest market at the time was in China.  Much of the pink and red tourmaline from San Diego County in California was shipped to China because the Chinese Dowager Empress Tz'u Hsi was especially fond of the color. There, craftsmen carved the tourmaline into snuff bottles and other pieces to be set in jewelry. San Diego County's famed tourmaline mines include the Tourmaline Queen, Tourmaline King, Stewart, Pala Chief, and Himalaya.

The miners became so dependent on Chinese trade that when the Chinese government collapsed in 1912, the US tourmaline trade also collapsed. The Himalaya mine stopped producing large volumes of gemstones. Other mines in San Diego County, like the Stewart Lithia mine at Pala, still produce sporadic supplies of gem-quality tourmaline.

	The Himalaya mine in Mesa Grande, California, produced this beautiful bicolor tourmaline
	crystal specimen. - Gift of William F. Larson

	The state of Maine has produced beautiful tourmalines. - Courtesy ICA/Courtesy of Boston Findings Co., Inc.

	A mine in California’s San Diego County produced this striking tourmaline. - Courtesy Bill and Jeanne Larson
The supply of tourmaline began to expand during the first half of the twentieth century, when Brazil yielded some large deposits. Then, beginning in the 1950s, additional finds appeared in countries around the world. Madagascar and Afghanistan have produced fine red tourmaline.

	Since the late 1980s, the Paraíba area of Brazil has been known as a source of strikingly intense tourmaline colors, called Paraíba tourmalines. @chapter:6 @chapter:0 @chapter:6


# Publication Year: 2019
# Title: Opals Revisited
# Abstract: Figure 1. The untouched opal specimen displays the yellow coating caused by years of storage in silicone oil. Photo by Ted Grussing.

In the 1980s, the author and his wife, Corky, acquired large quantities of Virgin Valley “wet” opal specimens displayed in glass domes with water and other specimens immersed in silicone oil. The domes had black rubber stoppers on the bottom. The mine representative had put them in water and silicone oil to enhance their beauty, since wetting the surface gives the illusion of a polished gem specimen.
Opal is a hydrated amorphous silica, and those with a high water content tend to craze and crack if left to dry. If a specimen is inclined to craze or crack, placing it in a liquid does not stabilize it or heal the cracks within, but it does delay the “day of reckoning” when the opal eventually deteriorates.
The specimens displayed in the domes with water began forming deposits, and within months the water became cloudy and the domes were crusted with precipitate from dissolved minerals. Those in silicone oil fared better, but eventually they too deteriorated, with the silicone oil taking on a yellow cast from the black rubber stoppers, which appeared to coat the opals with a yellow crust (figure 1).
After years of changing the water and silicone oil, the cleaning and repackaging eventually became very time-consuming. The author removed all the wet specimens from their domes, cleaned and wrapped them in paper towels, and put them in boxes. The boxes with the now-dry opal specimens were packed away and stored in the garage, where they remained for more than 27 years.

Figure 2. Left: The side of the specimen after cleaning and rubbing on a diamond wheel. Right: The nearly finished opal midway through the cleaning process. Photos by Ted Grussing.

Figure 3. The finished piece, dry and ready for display. Photo by Ted Grussing.
In July 2019, the author found the boxes containing these beautiful and long-forgotten opals. The results were astonishing. They had not fallen apart, and they looked more stable than they had when dried and put away. The cracks were still there, but the look was different. They looked like they could be worked—if not on the wheels, then with a flex shaft. The first opal that caught the author’s eye (again, see figure 1) was cleaned and worked (figure 2). The completed piece, shown in figure 3, is named “Bonnie Jean.” There are many more to finish, and they are dry and unlikely to craze or crack any further. @chapter:48 @chapter:0 @chapter:48


# Publication Year: 2017
# Title: Book Review: Jeweled Splendors of the Art Deco Era: The Prince and Princess Sadruddin Aga Khan Collection
# Abstract: By Sarah Davis, hardcover, 256 pp., illus., publ. by Thames & Hudson, New York, 2017, US$75.00

Jeweled Splendors of the Art Deco Era showcases the art and craft of jewelers, enamelists, lapidaries, and designers. It features 116 Art Deco masterworks, primarily cigarette cases, compacts and lipstick containers, and timepieces. Produced as a catalog for the April–August 2017 exhibition of the same name at Cooper Hewitt, Smithsonian Design Museum in New York, Jeweled Splendors is a book for any art collector or connoisseur of the jeweler’s art.

The works pictured are breathtaking in their craftsmanship, their ingenuity, and their astonishing use of color. Many exhibit perfectly smooth and glossy enameled surfaces. These are accented with either colored gemstones or platinum set with diamonds. Other surfaces are inlaid with hardstones and mother–of-pearl in painterly images. Some boxes are cut from a single block of agate or marble. The colors are bold yet harmonious. The term “feast for the eyes” is often overdone yet fitting here. Each image is clear and crisp, as if you could touch the object. The one thing missing is any way to experience the satisfying weight these gold objects must have in the hand.

The glorious items and the lush photography make it almost easy to overlook the three essays interwoven with the images, which are compact histories of Art Deco in general and the place of these objects in that history. The essays might also be overlooked because of the delicacy of the typeface chosen. Although this was probably a deliberate choice, made to allow the images to take center stage, the fineness of the type makes it difficult to read in low light. If there’s any complaint about the book, it is this.

The catalog text, written by Sarah Davis, an editor for the American Society of Jewelry Historians, is separate from the exhibit pieces. This is a welcome effort to avoid distracting readers from the beauty of the works. Yet the text is close at hand, placed at the end of each essay. Each entry is illustrated with a small color image—a pleasure for anyone who has tried to track down pieces at the back of a book by chasing catalog numbers. While Doug Rosa’s 348 magnificent photographs show each piece in exquisite detail and color, and make the book virtually impossible to put down, the three essays by three different curators are fascinating reading.

“East and West: Oriental Exoticism in the Decorative Arts,” by Evelyne Possémé of the Musée des Arts Décoratifs in Paris provides a brief history of the European “discovery” of art from the Middle East, India, China, and Japan and how it affected European decorative arts, inspiring designers to first copy and then merge artistic elements from a number of cultures. Chinese motifs and carvings were combined with Islamic garden design and graphic decoration. Japanese inro influenced the shape and style of the vanities that held women’s cosmetics and cigarettes in the Jazz Age. And enameled surfaces echoed the lacquer work of China and Japan. “European artists continued to feast on differences and discoveries, creating an art that constantly renewed and original,” writes Possémé. Eventually the elements of many cultures were refined and combined to such an extent that the style became a new one altogether: Art Deco.

“Feminine Elegance: Jeweled Accessories for the Modern Woman,” by Stephen Harrison at the Cleveland Museum of Art, examines the societal changes after World War I that contributed to demand for the kinds of objects featured in the exhibit. Mass-produced cigarettes became widely available, and cigarette companies promoted them as a sign of sophistication. Women, newly emancipated with their short, sleek fashions and bobbed hair, began frequenting jazz clubs with partners, and there they acquired the smoking habit. In fact, writes Harrison, women quickly became “the mainstay of a burgeoning tobacco industry.” They needed convenient cases, like men, to store and carry their cigarettes. But they also needed vanities to keep their makeup close by for freshening up. Cigarette cases became “artistic symbols of status, wealth and privilege” that embodied “taste, independence, and the means to achieve both.”

For designers, metalsmiths, enamelists, and jewelers, these containers provided much larger creative canvases than could be found in small jewelry pieces, and they pulled out all the stops in using those canvases to showcase “their finest techniques in jewelry setting, composition, artistic design, and mechanical innovation,” writes Harrison.

“Jeweled Innovation: Design and Manufacture in Art Deco Masterpieces,” by Sarah D. Coffin at Cooper Hewitt is a wonderful examination of the use of color, and how the unique mechanisms for opening these objects lent their own mystique and desirability. As the great jewelry houses realized the demand for these accessories, they began to carry them in their showrooms. And they began to compete aggressively for the business of the ultra-wealthy. This meant commissioning works by the finest box makers, or even partnering with or annexing them. The best artists often worked for several of the jewelry houses, frequently signing their work. Coffin relates the greens of enamel and stones such as aventurine to the relatively new creation of public gardens in Paris, and its symbolism of growth, and freshness. Black enamel, as used in these objects, was no longer the color of mourning, but paralleled the “little black dress” worn by women as they “stepped out” in the evenings; it also provided an excellent backdrop to the platinum and diamonds that decorated the works. But as a sign of modernity, and as a result of the competition for novelty between houses, intricate mechanisms were engineered for these pieces. They might be jeweled or hidden in clever ways. Compartments opened or slid from recesses. Lids opened at the push of a button, allowing them to be opened with one hand. (Many a movie from this era shows a sophisticated man opening a case with one hand to offer a cigarette.) Cases opened like envelopes, or drawers. Catches wrapped the edges or pierced lids. It was during this period, too, that Cartier introduced its Mystery clocks, and these are represented in the collection along with pendant watches concealed in elegant necklaces.

Jeweled Splendors of the Art Deco Era also includes an introduction by Princess Catherine Aga Khan, who received these beautiful gifts from Prince Sadruddin Aga Khan, and Pierre Rainero, the image and heritage director of Cartier, the firm that created many of these objects. The understated and exquisite book design is by Judith Hudson.

This is a book to return to again and again, a book to treasure. It is a deeply satisfying opportunity to examine, close up, a noteworthy collection. @chapter:20 @chapter:2 @chapter:20


# Publication Year: 2021
# Title: Neptunite Inclusion in Benitoite
# Abstract: This faceted benitoite contains a small reddish brown inclusion of neptunite that was identified by Raman spectroscopy. Photomicrograph by Nathan Renfro; field of view 1.20 mm. Courtesy of Michael Jakubowski.

The authors recently examined a round, slightly zoned blue and near-colorless faceted benitoite that contained an interesting inclusion. Microscopic observation revealed a well-formed euhedral semitransparent reddish brown crystal surrounded by fine short needles and fluid fingerprints (see above). Because of the color and structure of the inclusion, both neptunite and joaquinite were considered as the possible identity. In benitoite, these minerals are often found in association and may have a similar color to the inclusion observed in this particular example. One method of separating neptunite from joaquinite is pleochroism. A yellow-orange, orange, and deep red pleochroism is consistent with neptunite, while light yellow and colorless pleochroism is consistent with joaquinite (webmineral.com). This inclusion showed a reddish orange to red pleochroism that was more consistent with neptunite. Raman analysis confirmed the host crystal was benitoite and the orangy red inclusion was neptunite, which has been previously documented (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Vol. 1, 5th ed., 2008, Opinio-Verlag Publishers, Basel, Switzerland, p. 416).
Benitoite is a barium titanium silicate (BaTiSi3O9). This rare gem is found primarily in San Benito County, California, though it also occurs in other locations worldwide. Neptunite’s chemical formula is KNa2Li(Fe2+,Mn)2Ti2Si8O24, and it also occurs in San Benito County. Neptunite is found in association with other minerals in New Mexico, Greenland, and Canada, to name just a few (W.L. Roberts et al., Encyclopedia of Minerals, 2nd ed., 1990, Van Nostrand Reinhold, New York, pp. 603–604). The gem-quality benitoite material comes from the Benitoite Gem mine and the Junnila Claim (B. Laurs et al., “Benitoite from the New Idria District, San Benito County, California,” Fall 1997 G&G, pp. 166–187). This faceted benitoite contains one of the best examples of neptunite in benitoite seen by the authors. @chapter:15 @chapter:0 @chapter:15