Title: Color Modification of Spinel by Nickel (Ni) Diffusion: A New Treatment in the Gem Market Abstract: Figure 1. Suite of faceted nickel-diffused spinel (0.674–1.009 ct) showing the range of color from blue to bluish green. Photo by Aaron Palke and Diego Sanchez.
In November 2022, a parcel of 24 approximately 0.5–1.2 ct spinel crystals, described as cobalt-diffused, were obtained directly from a treater by the research team at GIA in Bangkok. Of these, seven possessed the deep blue color characteristic of cobalt diffusion, while the others showed lighter blue, greenish blue, bluish green, or blue-green color (figure 1). Slabs were cut from the core of several of these crystals, and all showed diffuse color zonation, from more blue/green at the rims to near-colorless at the cores.
The concentrations of various elements were measured along culet-to-table transects in the slabs using laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS). The expectation was that all crystals would show simple cobalt (Co) diffusion profiles, meaning high cobalt concentrations at the crystal edge, changing gradually to lower concentrations in the crystal core. This has been well described by Saeseaw et al. (2015). For the deep blue crystals, the result was as expected: high cobalt, thousands of atomic parts per million (ppma) at the crystal edge, changing gradually to low cobalt in the crystal core. This is clear evidence of cobalt diffusion treatment. However, all other crystals (i.e., those that were not deep blue) showed something quite different. The cobalt concentration in these crystals was negligible, generally below a few atomic ppm. The nickel (Ni) concentration, conversely, was extremely elevated, around 5,000 to 30,000 ppma at the rim and dropping to a few ppma in the crystal core. An initial conclusion was made that these “cobalt-diffused” spinel crystals were not cobalt-diffused at all, but rather nickel-diffused. Subsequent investigations using various absorption, luminescence, and fluorescence techniques, along with gemological observations, confirmed that the samples were indeed nickel-diffused and that natural spinel was used as the starting material. Additionally, nickel was confirmed to be the main chromophore responsible for the modified color. These observations are described in detail below, along with recommended identification criteria.
GEMOLOGICAL OBSERVATIONS
A total of 18 stones were studied. Standard gemological testing was consistent for spinel. Refractive indices were generally 1.718, but some samples varied up to 1.721, possibly due to the increased concentration of nickel at the surface. All samples were inert in long-wave UV light. Most were inert to short-wave UV, but a few showed faint chalky yellow fluorescence near the edges when prepared as doubly polished slabs. All faceted stones had a weak to strong red reaction when viewed through the Chelsea color filter. The doubly polished slabs viewed in this way showed color zonation: red at the rims and colorless in the centers.

Figure 2. Nickel-diffused spinel shows subtle color concentration along facet junctions (A and B) and features suggesting flux-assisted healing of the fractures during the heating process (C–F). Photos by Aaron Palke; fields of view 10.24 mm (A), 2.90 mm (B), 2.34 mm (C and D), 1.76 mm (E), and 1.99 mm (F).
When immersed in methylene iodide, the faceted stones showed a strong concentration of color around the rim of the stone, sometimes with additional subtle color concentration along the facet junctions (figure 2A). Microscopic observations sometimes showed this same color concentration along facet junctions, particularly at the keel of the stones (figure 2B), although the effect was more subtle than seen in other treated material, such as titanium-diffused sapphire. The most striking microscopic feature was the abundance of artificially healed fractures, likely associated with the presence of a flux material during the heating (figure 2, C–F). This is also supported by the trace element data, described below, which show high amounts of lithium at the crystal edge—lithium is a common component of flux material.
TRACE AND MINOR ELEMENT CONCENTRATIONS AND PROFILES
Even without quantification, the high nickel concentrations are obvious in X-ray fluorescence spectra (figure 3). These show clear peaks associated with nickel, with the main peak being the Kα emission line at around 7.47 keV. No samples from this suite showed fluorescence associated with cobalt.

Figure 3. An XRF spectrum of a nickel-diffused spinel (sample 17407067; see inset photo) acquired at 12 kV with an aluminum filter. Clear nickel fluorescence peaks are visible. The position of the main cobalt peak, absent in this spectrum, is shown.

Figure 4. A: Nickel concentrations measured on the girdles of nickel-diffused stones, along with the range of nickel concentrations seen in a subset of spinel crystals submitted to GIA. This subset includes natural, unheated spinel with the following hues: blue, bluish green, greenish blue, blue-green, green-blue. The nickel concentrations are considerably higher (100–10,000x) in the nickel-diffused stones. Also shown are the concentrations of lithium (B) and beryllium (C), both of which are also elevated at the crystal rims, as shown in the LA-ICP-MS transect (figure 5). Lithium concentrations are generally higher than the natural range, but beryllium concentrations are indistinguishable.
The concentration of nickel at the edge of the crystals was high, around 10000–30000 ppma (table 1), as measured using LA-ICP-MS spot analyses on the girdles of 13 stones. These nickel concentrations are very high when compared to natural gem-quality spinel submitted for analyses at GIA (figure 4A). It should be noted, however, that end-member nickel-spinel (chihmingite, NiAl2O4) has been found in nature.
Along with elevated nickel, some but not all crystals also showed high lithium (Li) concentrations, up to around 3000 ppma. Such high lithium is rare in natural, untreated gem spinel (figure 4B). Concentrations of other elements, even if added or removed during the diffusion treatment, were generally within normal ranges for gem spinel. Notably, this also includes beryllium (Be, figure 4C), despite beryllium showing increasing concentration toward the crystal edge in the LA-ICP-MS transect, described below (figure 5).

Additionally, the concentrations of all other measured elements were highly variable between stones. This implies either different treatment conditions or different starting materials. Preliminary analyses from the cores of some doubly polished slabs (not presented) showed different concentrations of elements other than Ni (those analyzed in table 1) in areas apparently unaffected by diffusion, suggesting that these concentration differences relate at least partially to different starting materials rather than different treatment conditions. At this point, however, we cannot confidently describe the nature of the starting materials.
Overall, the data show that nickel is a weak chromophore, as thousands to tens of thousands of ppma led to relatively weak colors. In contrast, cobalt diffusion treatment requires only a few hundred to thousands of ppma cobalt to create deep blue colors.

Figure 5. Concentrations of nickel, lithium, iron, zinc, vanadium, titanium, beryllium, manganese, gallium, chromium, and cobalt recorded along a ~3.3 mm culet-to-table transect across a slab cut from the core of a nickel-diffused spinel crystal (sample 17407124). Notably, nickel shows an extreme concentration decrease from rim to core, whereas cobalt shows a very small decrease with sub-ppm concentration along the whole transect.
In the crystal where trace element concentrations were recorded along a central transect (sample 17407124), nickel, lithium, beryllium, zinc (Zn), manganese (Mn), and cobalt show decreasing concentrations from the rim to the core (figure 5). All show U-shaped profiles. Ni shows the largest concentration change, from ~1 ppma in the core to ~5000 ppma at the rim. Cobalt shows the smallest change, from ~0.4 ppma at the core to ~0.8 ppma at the rim. Conversely, vanadium (V), iron (Fe), and magnesium (Mg) show inverted U-shaped profiles—i.e., lower concentrations at the rim than at the core—although the Mg profile cannot be accurately resolved using our LA-ICP-MS method. The Mg profile can be resolved using energy-dispersive spectroscopy (EDS), though, as described below. Chromium (Cr) and titanium (Ti) show variable concentrations, but neither show clear U-shaped or inverted U-shaped profiles. Gallium (Ga) shows no apparent concentration change.

Figure 6. Maps of nickel, magnesium, and aluminum recorded by energy-dispersive spectroscopy (EDS) from sample 17407069. Colors represent counts on nickel, magnesium, and aluminum normalized to total signal intensity by dividing by counts on oxygen (all Kα lines). The normalization was necessary given non-constant total signal across the mapped area. Color scales are set to maximize contrast; the ranges (normalized to O) are 0–0.04 for Ni, 0.85–1.2 for Mg, and 1–2.6 for Al. Also shown are profiles of magnesium and nickel, extracted from the maps in table-culet transects.
A central portion of another doubly polished slab (sample 17407069) was also mapped using EDS (figure 6), to complement the data from LA-ICP-MS analyses. This method has considerably higher spatial resolution than LA-ICP-MS but suffers from much poorer detection limits, so the only elements in the spinel that could be measured were nickel, magnesium (Mg), aluminum (Al), and oxygen (O). Nickel shows a clear concentration decrease from rim to core. Magnesium shows the opposite, and aluminum shows no apparent zonation. The zonation pattern of nickel conforms to the faceted stone’s shape, which implies that the diffusion treatment was conducted after faceting. This is consistent with the presence of color concentration at facet junctions.

Figure 7. UV-Vis spectra recorded from the near-rim regions of doubly polished slabs fabricated from nickel-diffused spinel crystals (lower four curves). Absorption coefficient is calculated as 2.303 x absorbance/thickness (cm). These were recorded by placing the stone over a 0.5 mm circular aperture, located as close as possible to the crystal edge at the table. Images of the stones are shown, along with 1 mm scale bars (solid gray lines). Also presented are concentrations of nickel recorded using a 50 μm LA-ICP-MS spot, centered at 50 μm from the crystal edge. This gives an approximation of the relative (between stones) nickel concentration, but is likely an overestimation of the mean nickel concentration in the area from which the UV-Vis spectrum was recorded given the nature of the nickel concentration gradients. Also shown are spectra recorded from a lab-grown nickel-doped MgAl2O4 powder and single crystal (Jouini et al., 2007; Serment et al., 2020); a lab-grown nickel-doped ZnAl2O4 powder (Lorenzi et al., 2006) and a cobalt-diffused spinel. The positions of the main bands in the nickel-diffused material are denoted by dashed lines.
ULTRAVIOLET/VISIBLE SPECTROSCOPY
Ultraviolet/visible (UV-Vis) spectra were recorded from the rims of several double-polished slabs (17407057, 17407126, 17407123, 17407124), using a 0.5 mm circular aperture. In all cases, the main peaks were at 369, 381, 475, 597, and 639 nm (figure 7). These positions are consistent with those present in spectra recorded from nickel-doped spinel powders synthesized for use as cyan dyes (Serment et al., 2020), nickel-doped single crystal spinel (Jouini et al., 2007), and nickel-doped gahnite spinel (ZnAl2O4; Lorenzi et al., 2006).
The peaks at 597 and 639 nm were assigned in this study to nickel in tetrahedral coordination (i.e., nickel generally replacing Mg2+). The peaks at 369 and 381 nm were associated with nickel in octahedral coordination, meaning nickel generally replacing Al3+. The band at 475 nm was not specifically defined by Serment et al. (2020), but it is notable that stones with a more intense 475 nm band appear to show a more green color. Figure 7 also shows a spectrum recorded from a cobalt-diffused spinel, obtained in the same parcel as these nickel-diffused crystals, showing clearly different absorption band positions.
The similarity between the absorption spectra from the nickel-diffused crystals, and a spectrum of single-crystal nickel-doped spinel grown in an argon atmosphere, suggests that the nickel is predominantly Ni2+, which would also likely be favored over Ni3+ at the high temperatures of diffusion treatment (likely 1600°C or higher).

Figure 8. PL spectra recorded from the rim (i) and core (ii) of a nickel-diffused natural spinel (sample 17407124), showing features characteristic of heating. Also shown is a spectrum from a natural, unheated high-nickel crystal (iii; >300 ppma Ni). Spectra are offset for clarity.
PHOTOLUMINESCENCE SPECTROSCOPY
Photoluminescence (PL) spectra recorded with 514 nm excitation are shown in figure 8. Spectra of the nickel-diffused stones are similar to natural, heat-treated spinel, which is in line with visual observations of inclusions and refractive indices. As with most natural spinel, the spectra are dominated by bands attributed to chromium. The spectra show broadening of the band(s) at around 686 nm. PL spectra recorded near the crystal rims are different from those recorded in the cores, with the rim spectra showing a dominant band at 687.5 nm, and core spectra showing a strong doublet with maxima at 685.6 and 687.3 nm. This may be associated with nickel, but it is notable that a spectrum recorded from a natural, unheated spinel with relatively high nickel (around 350 ppma) did not clearly show this feature. Spectra recorded from faceted stones using non-confocal PL spectroscopy will likely show some combination of these spectra.
DIFFUSION RATES AND MECHANISMS
The length scales over which the concentrations of the diffusing elements change, defined as the characteristic diffusion length, increases in the order V<Mn<Fe<Zn≈Co≈Ni<Be<Li (figure 5), suggesting a similar order for the relative diffusion coefficients. In other words, lithium diffuses more rapidly than vanadium.
The decrease in magnesium concentration from the core of the crystal to the edge (figure 6), associated with an increase in nickel concentration, is consistent with nickel addition associated with the removal of magnesium from the crystal. This would imply that the nickel primarily occupies the crystallographic site usually occupied by magnesium—i.e., the tetrahedral site in spinel. This is consistent with the UV-Vis spectra, where all crystals show predominantly tetrahedral nickel. Additionally, this is the expected mechanism of nickel incorporation, because the ionic radii for Ni2+ and Mg2+ are similar: 0.55 and 0.57 Å respectively (Shannon, 1976).
Some also show nickel in octahedral coordination, implying nickel on the aluminum site. This is expected at the high temperatures of diffusion treatment, which are unknown but possibly >1500°C. At these temperatures, spinel becomes disordered, meaning cations swap between sites.
The shapes of nickel diffusion profiles—i.e., the forms of concentration versus distance data in figure 5—correspond almost perfectly to the error function, a mathematical function often used to describe the shapes of diffusion profiles. Simply, this means that there is a smooth decrease in nickel concentration, and associated color, from the edge of a crystal to the core. This implies that diffusion in this system is relatively simple, with little or no trapping behavior—such non-simple behavior could be expressed as sharp color changes, as is often observed in titanium-diffused sapphires, for example. The likely diffusion mechanism would then involve simple exchange of Mg (tetrahedral) vacancies with Ni2+, which has been proposed as one mechanism of Cr3+ diffusion in spinel (Posner et al., 2016).
SUMMARY OF CRITERIA FOR IDENTIFICATION
According to our current study of these stones, the following criteria are proposed for identification of nickel diffusion treatment in spinel:

High concentrations of nickel at the crystal faces, potentially thousands of atomic parts per million or more. This may be associated with high lithium concentrations.
Photoluminescence spectra characteristic of heated, natural spinel, although the possibility of treatment of lab-grown spinel is not ruled out.
Characteristic UV-Vis absorption spectra, with bands at around 370, 470, and 600 nm.
Subtle color concentrations at the facet junctions, although this may be limited if the stones are repolished after treatment.
Textures associated with flux-assisted healing of fractures.

Overall, the treatment should be readily identifiable using standard gemological techniques and equipment. Source: GIA @topic:3


Title: Hidden Gems at the San Diego Natural History Museum Abstract: Figure 1. A gem pocket replica highlighting various gems and minerals mined in San Diego County, including tourmaline, quartz, kunzite, aquamarine, and mica. Dubbed the “Miner’s Fantasy Mine,” this replica combines various gems and minerals in the same pocket for illustrative purposes only. Photo courtesy of the San Diego Natural History Museum.
Known locally as The Nat, the San Diego Natural History Museum is making good use of unoccupied space with its Hidden Gems exhibit. Spanning the five floors of the museum, the 2,000 square foot vertical gem and mineral exhibit fills the space outside of the elevators on each floor, providing a permanent home to more than 100 specimens from the museum’s collection, many of which had not been on display prior to the exhibit’s opening. In this vertical exploration, visitors can expect to be wowed with a different experience as they reach each level of the museum.
Each floor has its own theme designed to showcase the diversity of minerals from all over the world. Fluorescent minerals are aglow under black lights on the lower level. Level 1 displays a sampling of gems from all over the world, with a special case dedicated to birthstones from GIA. Level 2 is comprised entirely of gems mined locally in San Diego County, California, including quartz, topaz, and hot pink tourmaline. This level also features a replica gem pocket full of gemstones found in the area (figure 1). Level 3 focuses on the application of minerals in the real world, including a section highlighting the minerals used to make cell phones. Finally, Level 4 covers geologic diversity, presenting a wide array of gems and minerals of different colors, shapes, and sizes. After experiencing all five floors, visitors leave with an understanding of the many roles of gems and minerals—aesthetic, geological, and practical.

Figure 2. An image of quartz agate from Chihuahua, Mexico, scanned from the specimen and used to create wallpaper featured on Level 4 of the museum. Photo courtesy of the San Diego Natural History Museum.
The walls and ceilings of the exhibit also deserve honorable mention. Large-scale murals produced by scanning various mineral specimens and printing them on the wallpaper create the feeling of walking into the featured mineral (figure 2). And a 24-foot sculpture modeled after the crystalline structure of silicate dangles from the ceiling.
Hidden Gems is a long-term exhibit and will occupy the space outside the elevators for the near future, until the museum unveils another innovative exhibit to fascinate visitors. For now, Hidden Gems is a vertical delight for all to see. Visit https://www.sdnhm.org/exhibitions/hidden-gems/ to learn more. Source: GIA @topic:7


Title: Spectral Differentiation Between Copper and Iron Colorants in Gem Tourmalines Abstract: The authors used Vis-NIR spectral measurements combined with LA-ICP-MS data to investigate the usefulness of absorption spectra for differentiating between copper and iron as sources of greenish blue coloration in gem tourmaline. While both Cu2+ and Fe2+ produce absorption bands with maxima near 700 nm, Cu2+ also has a strong band with a maximum near 900–925 nm, where absorption due to Fe2+ is typically at a minimum. In addition, Vis-NIR spectroscopy successfully identified Cu in pink/purple and violet stones that could be candidates for heat treatment. For the blue, green, and violet Cu-bearing tourmalines of pale-to-moderate color intensity in this study, weight percent of CuO could be estimated from the absorbance at 900 nm. This relatively inexpensive identification method may prove to be a valuable screening tool for Cu-bearing tourmaline.

	DATA DEPOSITORY

Additional Spectra
Average LA-ICP-MS Data (ppm by Weight) of the Tourmaline Samples
	Summer, 2009 Source: GIA @topic:11


Title: Somewhere in the Rainbow Finds a Home at the Alfie Norville Gem and Mineral Museum Abstract: Figure 1. This 203 × 254 mm azurite mineral specimen from Bisbee, Arizona, is emblematic of the strong mineral representation of the Southwest at the Alfie Norville Gem and Mineral Museum. Photo by Jeff Scovil; courtesy of the Alfie Norville Gem and Mineral Museum.

A decade ago, a private gemstone collection was established to celebrate their beauty and stimulate curiosity and gemological education. Today, the Somewhere in the Rainbow collection has found a prominent new home.

Somewhere in the Rainbow joins the University of Arizona’s renowned mineral collection consisting of 20,000 global specimens, which is also noted for its strength in minerals from the southwestern United States and Mexico. Together with the Somewhere in the Rainbow collection (a large part of it exhibited under a five-year agreement), 6,000 of the finest mineral specimens will be on exhibit (figure 1) at the new Alfie Norville Gem and Mineral Museum, located at the historic Pima County Courthouse in downtown Tucson (figure 2). The museum is on the verge of reopening in 2021, says manager Eric Fritz. Its location in Tucson is apt, given that the city is a global destination for gemstones, minerals, and the visitors who trade in them.

Figure 2. The Alfie Norville Gem and Mineral Museum will be housed at Tucson’s recently refurbished Pima County Courthouse. The building renovation cost over US$30 million. Courtesy of the Alfie Norville Gem and Mineral Museum.

The museum is named after the wife of noted Tucson real estate developer Allan Norville. In the 1990s, the couple founded the Gem and Jewelry Exchange (GJX), which remains a major force among the many shows that come to Tucson every year. To date, more than 40 gem and mineral shows exhibit across the town every January and February. The Norvilles are major patrons of the new museum.

At 1,600 pieces and counting, the Somewhere in the Rainbow collection consists mainly of finished gem material complementing the mineral displays (see below). Its strength lies in gem carvings, loose gemstones, and jewelry. This collection has traveled across the United States in recent years, visiting AGS Guild stores and other high-end retailers. Its mission is “to bring hands-on education and enjoyment of fine colored gems to museums, galleries, gemologists, and facilities dedicated to preserving the rarity, history, and beauty of the gems and articles of jewelry.”

Shelly Sergent, the Somewhere in the Rainbow collection’s manager, is credited with building it at the behest of unnamed patrons. She says that it offers the public, students, scientists, and educators a distinct snapshot of the gemstone supply chain. “Mother Nature gives us rocks. Cutters and carvers give us gemstones, and jewelry designers give us heirlooms,” Sergent explains.

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The collection provides enthusiasts with a better understanding of the beauty and rarity—as well as the unique collaboration between nature and artists. “I realize truly that our mission is not only about education—it’s about community,” says Ms. Sergent. “In that regard, we have brought together more than 127 different people that have worked with us in some capacity on this collection, whether that be miners, stone chasers, lapidary artists, designers, jewelers, and the heads of different laboratories.”

Ahead of the Alfie Norville Gem and Mineral Museum’s 2021 reopening, GIA had the opportunity to visit with Sergent to examine, handle, and photograph some of the collection’s significant pieces. The accompanying photo gallery offers just some of the highlights. Source: GIA @topic:7


Title: Stephen M. Avery: Celebrating Half a Century in Gem Cutting Abstract: Figure 1. With names like “Flaming Comet” and “It’s a Zoisite Party,” Avery’s gem sets have enchanted for decades. This three-piece set consists of a 6.22 ct golden tourmaline flanked by two aquamarines, 5.14 carats total. Photo by Sara Rey; courtesy of Stephen M. Avery.
Approaching his 50th anniversary in the business, Stephen M. Avery (Lakewood, Colorado) reflected on his journey to becoming an award-winning lapidary artist, detailing his signature cuts and gem sets and offering advice to up-and-coming gemstone cutters. Since starting his career at the age of 17, Avery has accumulated a remarkable amount of cutting experience. But even after all this time, the part he enjoys most is continuing to find new challenges.
Avery was not born into the business and began his career by enrolling in the American School of Diamond Cutting. He learned the foundations of diamond cutting from the prestigious diamond cutter Leonard Ludel. A few years later, he found himself working for Stradley Lapidary in Colorado, where he made the instinctual move from diamonds to colored stones. He describes this as a moment of clarity, as he was bored with the lack of creativity in cutting standard round brilliant diamonds. Avery noted that at the beginning of his career in the late 1970s, he was “bringing something unknown to the colored stones business: diamond cutting quality to colored gemstones.”
Avery started to create gem sets—suites of intricately cut gemstones that fit perfectly together (figure 1)—about 40 years ago. He describes them as something that started experimentally and has exploded in popularity. When it comes to creating his gem sets and sourcing the right stones, he has learned that patience pays off. He explained that some colors will negatively impact other colors, and some colors when paired will read neutral. The most gratifying outcome occurs when all the gemstones used look better when they’re together.
Throughout his career, Avery has fashioned numerous signature cuts. His very first signature cut was a Portuguese-cut trilliant, which took three years to design. Another early signature cut was the Triopp cut (figure 2), a triangular cut born out of anger when the perfect trillion preform had an inclusion in the corner. He ground it out, only to discover a completely new concept in faceting. He then went on to create the OVOB cut, an oval opposed bar cut, and most recently the Diamondback, a recreation of the checkerboard cut to fit elongated pieces of gem rough (figure 3).

Figure 2. When skill and experimentation combine, something as brilliant as Avery’s signature Triopp cut is born. This stunning example is a 9.79 ct chrome tourmaline measuring 14.5 mm. Photo by Sara Rey; courtesy of Stephen M. Avery.

Figure 3. Avery’s Diamondback cut is a blessing to stones longer than 50 mm. This 73.22 ct tourmaline measures 11.1 × 79.3 mm. Photo by Sara Rey; courtesy of Stephen M. Avery.
His exquisite attention to detail and understanding of color and light enable Avery to cut award-winning, one-of-a-kind faceted gemstones. The majority of his pieces require designers to create custom settings. He has relationships with several skillful designers who allow him to share his vision for the piece and then take it from there. His talent, in combination with the talent of these designers, has earned him many “Best Of” titles in the AGTA Spectrum Awards. Avery cut a matching pair of Afghanistan indicolite tourmalines that were 2018 AGTA Cutting Edge Awards first-place winners in Pairs and Suites. The following year, those same tourmalines won yet again in the Spectrum Awards, in earrings designed by Adam Neeley (figure 4).

Figure 4. 2019 AGTA Spectrum Award–winning earrings designed by Adam Neeley with a pair of indicolite tourmalines cut by Stephen Avery, weighing 41.45 carats total. Other stones are tsavorite garnets (3.34 carats total) and diamonds (2.42 carats total) set in purple titanium, 14K white gold, and green VeraGold. Photo by Sara Rey; courtesy of Stephen M. Avery.
Avery shared his advice for emerging gem cutters: “Learn all the techniques, then challenge the rules. If you want to do something and you don’t have the technique, you’re going to have to invent it. And that’s okay—it just hasn’t been done because you didn’t do it yet.”

	Stephen M. Avery: Master Gem Cutter Source: GIA @topic:7


Title: Exceptional Gem Artistry in Sunstone, Rutilated Quartz, and Beryl – Tucson 2014 Abstract: Figure 1. The morganite carving on the left was inspired by the floating watches in the famous Salvador Dali painting “The Persistence of Memory.” The geometric carvings on the right look simple when the stone is viewed from the base but produce an array of bright reflections and crystalline brilliance when viewed from above. Photo by Eric Welch; courtesy of Sonja Kreis.

	Alexander KreisUnique Jewelry

	In this series of three videos, Idar Oberstein-trained gem cutter Alexander Kreis relates the different approaches he takes to unlock the beauty of a variety of rough gemstones, which include Oregon sunstone, various beryl colors, and rutilated quartz. He tells us the influences that play into his unique designs; it might be the pure, crystalline beauty of a flawless piece of rough or the presence of striking inclusions, which drive him to produce beautiful pieces of wearable art.
At the GJX show, Sonja Kreis (Unique Jewelry, Niederworresbach, Germany) displayed exceptional examples of the jeweler’s and gem carver’s art. Kreis designs the jewelry, and her son Alexander cuts the gems.

	Figure 2. The Oregon sunstones in this fantasy-cut pendant and ring, displaying deep red color and intense stripes of schiller, were cut from the same piece of rough. Photo by Eric Welch; courtesy of Sonja Kreis.

	Figure 3. Left: Alexander Kreis displays one of his unique pieces: a star-shaped rutilated quartz. Right: This superb 442.78 ct faceted Brazilian quartz with rutile inclusions is typical of Kreis’s art. According to Kreis, the orientation of the needles is the most important decision in the design of the finished gem. Photos by Eric Welch (left) and Robert Weldon (right); courtesy of Sonja Kreis.
Alexander Kreis explained that their family has a tradition of over 500 years of gemstone cutting and jewelry manufacture. He apprenticed as a traditional gem cutter, but elected to find his own path to unlock the beauty of fine gem crystals. His cutting is a spectacular blend of freeform curves and dramatic geometrical cuts. Alexander works with many materials, including tourmalines and beryls (figure 1), but Oregon sunstones (figure 2) and rutilated quartz (figure 3) are among his favorites. The fine Oregon sunstone was on display at their booth. Alexander’s father, Stefan Kreis, described their very strict criteria for selecting rough. On a visit to a set of mines in Oregon’s Rabbit Basin, they selected 395 grams of rough out of the 50 kg they were shown; one such piece of rough is featured in figure 2. Source: GIA @topic:10


Title: Arizona Road Trips: Wild West Gem and Mineral Localities Abstract: “Wulfenite is Loved” was the theme of the Tucson Gem and Mineral Show in 2019. This 33.80 g wulfenite crystal on matrix is from the Red Cloud Mine, Arizona. Gift of Donald and Ruth Miliken. Photo by Orasa Weldon/GIA

Arizona’s scenic desert and mountain landscape is the perfect backdrop for a modern Wild West road trip ‒ and researching mines for a road trip to gem localities there uncovers stories worthy of a Western movie script.
Red Cloud Mine, La Paz County
Working a desert mine was challenging in the rugged, hot landscape with little access to water, rudimentary shelter and an “every man for himself” attitude that often led to murder in the rowdy mining towns of the West.

This map shows the locations of the mines, towns and natural areas where some gems are found in Arizona.
The story of the Red Cloud Mine, located in the southwest corner of Arizona, is set in the gold and silver rush days of the late 1800s and bears just such a story of riches, crime and redemption. Prospector Warren Hammond pawned his shotgun in Yuma, Arizona in 1880 and headed north to stake a claim in an area that would later become the La Paz County Silver District. He struck pay dirt and named the mine Red Cloud after the trail used by early Spanish explorers.
The silver mine flourished and grew to employ 100 miners and the nearby town of Silent expanded to include an assay office, hotel, dance hall and saloons. One saloon owner, according to local history, was shot by a rival who pleaded self-defense, was exonerated and later appointed postmaster.
Silver from the Red Cloud mine has long been dispersed, and the mine is closed, but the mineral wulfenite found there has made its way into collections worldwide. It is known as some of the world’s best for its yellow-orange and red-orange color, as well as its high luster.

This graceful freeform azurite carving from Arizona reveals accents of malachite. Gift of the Larson Family. Photo by Orasa Weldon/GIA
Bisbee
Consider taking a break after the upcoming Tucson Gem & Mineral Show and drive about two hours south on Interstate 10 to Bisbee, an Old West mining town that retains its heritage with historical museums, art galleries and mine tours.
During its heyday, Bisbee was a remote, dangerous, and desolate area where the Apaches roamed the mountains and valleys to protect their land from settlers. Bandits sought refuge in the desolate area or preyed on the vulnerable passing through.
Hundreds of thousands of tons of silver, copper, lead and other ores were produced in the Bisbee area. The area’s legacy, however, lies in the more than 300 mineral species that have been uncovered in the search for silver. Azurite, malachite and turquoise are among the most well-known.

An 18.97 ct polished freeform Chrysocolla gem with areas of drusy quartz and a 33.30 ct. Chrysocolla oval cabochon. Both are from Arizona. Gift of Bill Larson. Photo by Orasa Weldon/GIA
The Ray Mine, Pinal County
The Ray Mine, located 85 miles east of Tucson, is nestled below Teapot Mountain about 12 miles south of Superior on Highway 177. Prior to the late 1870s, local Native Americans worked the copper deposits. By 1880, modern mining operations were set in motion, but it was the railroad line in 1905 that made it possible for the ore to be shipped for processing.
The Ray Mine is famous for its twinned blades of native copper crystals, chrysocolla, malachite, quartz and chalcedony. Owned by ASARCO, the operations and equipment of the Ray mine are available for viewing daily from 7 a.m. to 2 p.m. or until dusk.

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Galiuro Mountains
From the Ray Mine head east on Interstate 70 toward the eastern foothills of the Galiuro Mountains southwest of Safford. This region is known for Deer Creek fire agates. There are several mining claims in the area, so be sure to honor private property rights.
In general, it is always prudent to consult with claim holders or owners before venturing out for prospecting on your own.

This 28-ct Four Peaks Mine amethyst shows flashes of red that are characteristic of this locality. Courtesy of Commercial Mineral Company, Inc. Photo by Robert Weldon/GIA
Four Peaks Amethyst Mine, Fountain Hills
The Four Peaks Amethyst Mine is located about two hours east and north of Phoenix in a remote area of the Four Peaks Wilderness area of the Tonto National Forest. Amethyst from this locality exhibits a rich purple hue with flashes of red and blue, and is called Siberian amethyst in the trade. It is rare and collectible both for color and scarcity.
For the adventurer, tours by helicopter or jeep to the Four Peaks mine are availableby appointment from a local business in Fountain Hills, Arizona.

Sleeping Beauty turquoise is the main attraction in these earrings set in 18K white gold and accented with 0.83 ct diamonds. Courtesy of Andrew Sarosi, Los Angeles. Photo by Robert Weldon/GIA
Sleeping Beauty Mine, Globe
On your way to San Carlos Apache Reservation, you will pass through the town of Globe where the Sleeping Beauty Mine is located. The mine, which produced the finest turquoise in the United States, shifted its focus from turquoise to copper in 2012.
San Carlos Apache Reservation, Peridot
The San Carlos Apache Reservation and the Cultural Center are located about 2.5 hours and 135 miles east of Phoenix on U.S. 70 near the town of Peridot, which is named for the world’s largest deposit of the gemstone. Mining of peridot is only granted to residents of the reservation. It is extracted with hand tools and collected in buckets. Garnets are also found on the reservation.

This group of peridot rough is from San Carlos, Arizona. Gift of John and Patricia Furhbach. Photo by Robert Weldon/GIA
Petrified Forest National Park, Holbrook
An Arizona road trip would not be complete without a drive through the Petrified Forest National Park in northeastern Arizona. Located 110 miles east of Flagstaff along Interstate 40 near Holbrook, the southern portion of the park is full of colorful petrified wood. It is strictly forbidden to remove or collect specimens in National Parks or Monuments. Contact the Bureau of Land Management for areas that allow collection.
The prospect of finding a fortune in gems or minerals on this Arizona road trip is rare, but the memories you collect on your journey will be priceless. Source: GIA @topic:1


Title: Book Review: Masterpieces in Miniature: Engraved Gems from Prehistory to the Present Abstract: By John Boardman and Claudia Wagner, hardcover, 304 pp., illus., publ. by Philip Wilson Publishers, London, 2018, US$72.00.

Gemstone engraving, also known as glyptic art, is considered to be one of the oldest crafts. Engraved stones were used to record ownership and signature as seal stones, a practice that continues today. Their use eventually extended to adornment within jewelry and decoration. The ancients valued engraved gems, both in intaglio and cameo forms, and recorded important events, people, and mythical and religious scenes on them. The artistry and skill required for the production of engravings were exceptional, considering the ancients did not have magnification. Later, during the Renaissance and Neoclassical periods, the appreciation and almost obsessive collection of these gems was a trend of the European elite. This resulted in the revival of engraving art, which typically copied the classical subjects and added the engraver’s interpretation. These collections of the 16th and 17th centuries are the basis of significant museum collections today.
Masterpieces in Miniature: Engraved Gems from Prehistory to the Present presents an exquisite private collection of engraved gems assembled almost a century ago by a notable ancient art expert. The pieces are derived mainly from older, previously unpublished European collections. The book covers a wide range of engraved gems, from the Greek Bronze Age to the Classical, Hellenistic, Graeco-Roman, and Roman eras, and then delves into gems engraved as late as the 18th century CE. The last chapter includes 12 engraved metal rings. The book was written in association with the Beazley Archive of the Classical Art Research Centre, Oxford University, which offers a large selection of resources for ancient gem studies.
This volume is beautifully illustrated and superbly written. In clear, scholarly language, the preface explains the history and challenges of glyphic art and unfolds the materials, geographies, and cultural aspects of engraved gems era by era. The preface gives excellent insight and necessary education before the reader indulges in the detailed images and backgrounds of the 251 pieces.
The reader will appreciate the authors’ examination of the subject from both academic and collector perspectives, as would a modern gem collector or gemologist. However, from a research gemologist’s point of view, the book provides great examples of the nomenclature issues we face on a daily basis that are ingrained in the historical studies, and it will take some time for scientists in history and archaeology to embrace modern gemological terminology. To be precise, a number of engraved gems are identified with old terminology, such as “plasma” or “hyacinthine [sic] garnet,” where they could easily be identified more unambiguously by a trained gemologist. It is even more puzzling, yet pleasing, to see identifications of “chromium chalcedony,” a term specific to chromium-colored chalcedony that requires particular gem-testing methods to identify. Very few gemologists conduct research on ancient gems, but the number is increasing. A noteworthy publication such as this one would benefit from a multidisciplinary approach to attract and fascinate more readers with different backgrounds.
Masterpieces in Miniature: Engraved Gems from Prehistory to the Present is a masterpiece itself and highly recommended to any gem enthusiast, even those not previously captivated by ancient gems. Collectors, historians, and connoisseurs alike will be delighted by this volume. Source: GIA @topic:6


Title: St. Jude Kids Tour Inside Gems’ Magical World Abstract: St. Jude patients and their siblings had a chance to view gems with a microscope at the GIA GemKids event at the hospital. Kimberly Overlin, dean of students at GIA in Carlsbad, helped the children use the microscopes. Photo courtesy of St. Jude Children's Research Hospital.

The world inside of gemstones can be magical – a journey through crystalline forms and colors – especially to the vivid imagination of a curious child.
Young patients at St. Jude Children’s Research Hospital in Memphis were guided inside this amazing world by a GIA team who brought gems and minerals to the leading medical facility, known for its treatment of childhood cancers and other pediatric diseases.
Families never receive a bill from St. Jude for treatment, travel, housing or food – because all a family should worry about is helping their child live, according to a St. Jude spokesperson.
“St. Jude Children’s Research Hospital is leading the way the world understands, treats and defeats childhood cancer and other life-threatening diseases. Our purpose is clear: Finding cures. Saving children,” a St. Jude spokesperson said. “Treatments invented at St. Jude have helped push the overall childhood cancer survival rate from 20 percent to 80 percent since the hospital opened more than 50 years ago.”
St. Jude’s board invited GIA to visit as an outgrowth of the Institute’s work with Jewelers for Children, a jewelry industry nonprofit organization that helps children in need, including at St. Jude and several other institutions.
“These are special kids and they were thrilled at what we brought for them,” said Judi Schechter, director of global business development and beneficiation for GIA, who accompanied the group on the November 2018 visit. The gems included 24 hands-on specimens such as pyrite, a ruby in zoisite matrix, green fluorite, several geodes, various types of quartz crystals, agates and an amber ring with an ant inclusion.
“The kids loved that amber ring with the ant,” said Kelly Bennett, who supervises GIA’s GemKids program. “And the pyrite was also a hit.”
The GIA team set up a table near the St. Jude cafeteria during time when the kids and their visiting families had some free time. Six microscopes, the gem specimens and GemKids educational workbooks, which the Institute provides to school children who participate in the on-campus program, were available for exploration.
The children could handle the crystals and other mineral specimens, but it was the microscope views that really brought the “wows,” as they viewed several synthetic sapphires, a synthetic emerald, a natural feldspar and quartz.
“Most of the kids had never looked at gemstones with a microscope, so it was all new and exciting for them,” Schechter said. “They got to look, touch and feel the gem specimens and look through the microscope to see inclusions and other internal features. It was all very hands-on.”

Judi Schechter, director of global business development and beneficiation for GIA, hugs a patient’s sibling at the event. Photo courtesy of St. Jude Children's Research Hospital.
Kimberly Overlin, GIA’s dean of students, was also part of the GIA delegation and noted that about 50 children visited the table. “Most of them went away really enthusiastic,” she said.
The visit was organized through the GIA’s GemKids program, which is based in Carlsbad and provides an engaging gemology learning experience to local students aged 9 to 12 - nearly 5,000 students a year. GemKids programs are offered at its Carlsbad campus and several locations in Africa, including Botswana and South Africa. Using hands-on activities in a fun and interactive environment, the program is intended to instill a passion for the science of gemstones.

The GemKids website is a digital resource that teaches kids about gems and jewelry, including what different careers in the jewelry industry do and a glossary of gemological and jewelry search terms. There are also easy and interactive GemKids materials available online for students, parents and teachers.
While there are no specific plans to return to St. Jude, Schechter said the experience was “so heartwarming. We were all in tears – joyful tears—the entire time we were there.” Source: GIA @topic:7


Title: Gem Guide Delivers Education, Social Return to Artisanal Miners Abstract: A miner in Tunduru, Tanzania examines the artisanal mining guide following GIA’s lecture on the subject. Photo by Robert Weldon/GIA

Free educational tools provided to miners in some rural areas of Tanzania are helping them reap greater profits.
“[The miners] can sort, they know how to wash and add value into the material … They are really now getting more money than when they didn’t have this project. It has added a lot of value into their life using a book and using a tray,” said Salma Kundi Ernest, secretary general of the Tanzanian Women’s Mining Association (TAWOMA), speaking through an interpreter at the Chicago Responsible Jewelry Conference, held in October 2018.

The artisanal miners gleaned this valuable knowledge from “Selecting Gem Rough: A Guide for Artisanal Miners,” an illustrated book developed by GIA (Gemological Institute of America) to help small-scale miners learn more about the quality and classification of the gems they recover.

Artisanal small-scale (ASM) miners, working in small teams using only hand tools, mine many of the colored gemstones from Tanzania and other areas around the world. They often live and work in remote areas where there are few other opportunities to earn a living and have little or no access to information about the stones they recover. Having even simple information about gem quality and an understanding of market needs puts them in a stronger position to negotiate with buyers.

The GIA team produced a video of their more recent Tanzania trip that captures the setting of the mines, work in the field and the interactions they had with the miners. Norbert Massay, Marvin Wambua and Robert Weldon talk about the effects of the program on the artisanal miners. Video produced by Pedro Padua/GIA
The “GIA Guide for Artisanal Miners” is a photo-rich booklet written in Swahili with photos of the rough gemstones found in East Africa, including tourmaline, corundum, various types of garnet, topaz, spinel, zircon and tanzanite. Since most of the miners have little formal education, the information is presented primarily in pictures, with limited text. Accompanying the water-proof booklet is a durable plastic translucent tray that can be used to sort gems and do other basic gemological evaluations. The pictorial instructions guide the miners – including those who cannot read – on how to evaluate the quality of the rough.

Other illustrations show how to use the tray to view the rough gem material using both direct and transmitted light to best evaluate the gem’s characteristics and how to clean it. A section at the end shows the stages of gemstone cutting from sawing to pre-forming and faceting, and then how a stone is mounted into jewelry. This information gives the miners a better understanding of the market value chain.

GIA contracted with Pact, a Washington, D.C.-based non-governmental development organization with offices in Tanzania and extensive expertise and experience in the region, to conduct two pilot studies – one in 2017 and one in 2018. The first pilot trained approximately 400 artisanal small-scale miners in the Tanga region near the northern border of Tanzania, which GIA and Pact selected because of the diversity of alluvial gemstone deposits in this area. The initial participants were members of TAWOMA.

“We were keen to involve TAWOMA because female miners have faced even more challenges than their male counterparts: sex discrimination, exclusion from some mining sites, less mining knowledge, less access to capital and less education in general,” said Cristina Villegas, director of the Mines to Market program at Pact. “When it comes to education, why not start with women?”

The second pilot distribution reached approximately 750 additional miners in the gem-rich regions of Tunduru, Songea (in southern Tanzania) and Morogoro (in central Tanzania). The Tanzanian government was informed about each of GIA and Pact’s visits and endorsed their efforts. Norbert Massay from Pact provided travel logistics, government contacts and information about mining localities.

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GIA staff, including Robert Weldon, director of the Richard T. Liddicoat Gemological Library and Information Center at GIA and co-author of the guide, and GIA Graduate Gemologist (GG) Marvin Wambua from Kenya, trained artisanal miners in how to use the guide and translucent tray. All of the miners, who were surveyed several months after being trained, said they developed a solid understanding of the gemological concepts presented. The survey results also revealed that they gained confidence in evaluating the quality of rough they found, which dramatically improved their bargaining power with local buyers.

Wambua, who is also a gem cutter, noted the higher quality of the rough offered from the mining groups. “Prior to the program,” he said, “we didn’t see anything worth cutting. But as we progressed, quality in the samples improved. On our follow-up visit in Tanga, I saw gems worth working on.”

One miner noted that learning how to wash gemstone rough properly made it possible to evaluate the quality of the color and clarity of her finds. Another said that this ability enabled him to separate gems by type and quality, which got him much higher prices in the market.

“I have sold my garnet for 70,000 Tanzanian shillings (about $30 US) after the training. Before I would have received a maximum of 10,000 shillings,” a female miner from Kalalani (near Tanga) told Pact.

Pact calculated that the the knowledge gained from GIA’s $120,000 initial investment in the project – funded by the GIA Endowment fund – generated a 12-fold social return on investment (SROI) to the miners and would continue to help them in coming years.

Massay reported that benefits from the gem guide extend far beyond the miners themselves. “I can see how this is changing things here. People have more money, more kids are in school, more of them have school uniforms and people are building brick houses. All of this shows that it is bringing more value into peoples’ lives,” he said.

Female miners, who face more challenges than men, can use what they learn from the guide to better evaluate what they recover. Photo by Robert Weldon/GIA
The idea for the gem guide project started with Dr. James Shigley, GIA Distinguished Research Fellow, following a 2008 trip to Kenya and Tanzania. Seeing the artisanal miners working under difficult conditions, he started thinking about the best way to help them. He, together with GIA library staff, developed the text and photos for the guide, with extensive consultation with other experts in the gem trade. First developed in English, the booklet was later translated by Wambua into Swahili.

GIA assumed all of the costs for the pilot project from its endowment fund and will continue to provide the book, tray and training free of charge as the program expands in East Africa and other potential gem localities.

“This is core to the GIA’s mission,” said GIA President and CEO, Susan Jacques. “We are moving practical gemological knowledge to the beginning of the supply chain for the people who can benefit from it tremendously,” she said. “This guidebook brings artisanal miners understanding about the value of the beautiful gems they bring to market.”

Weldon, who was involved with many of the phases of the project, was pleased to see the positive impact the gem guide had on the artisanal miners’ lives and work.

“An understanding of the very basic needs of African miners at the beginning of the supply chain was absolutely key for this to work,” he said. “It is truly humbling to see that the knowledge gained by the miners is helping so much. As they begin to understand the complexity of the supply chain, and how gems are used, these miners can aspire to different jobs, such as cutting and jewelry making.” Source: GIA @topic:7


Title: New Deposits of Gem-Quality Common Opal from Michoacán, Mexico Abstract: Figure 1. Gem-quality common opal was recently discovered in Michoacán State in western central Mexico. The approximate size of this sample is 15.04 × 7.68 × 5.57 cm. Photo by M. Ostrooumov.

Recently, the author discovered new deposits of common gem opal (figure 1) in the hills near Lake Cuitzeo, in Mexico’s Michoacán State. These opals were embedded in volcanic andesitic rocks. They were generally characterized by a medium to light orange to brown color, with no visible inclusions. While these new deposits are considered “common opal” since the material does not show play-of color, some gemologists may also consider the specimens to be fire opal due to the orangy bodycolor. The samples were studied at the Institute of Earth Sciences at the University of Michoacán in Morelia.

Standard gemological testing yielded refractive indices between 1.440 and 1.457 and hydrostatic specific gravities (SGs) ranging from 2.11 to 2.14. The material was inert to both long- and short-wave UV radiation. These properties suggested common opal, which we later confirmed with scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), Raman microprobe, and infrared spectroscopy.

Previous research (E. Fritsch et al., “Mexican gem opals: Nano-and micro-structure, origin of colour, comparison with other common opals of gemmological significance,” Australian Gemmologist, Vol. 21, No. 6, 2002, pp. 230–233) has shown that Mexican opals with play-of-color exhibit a higher degree of organization. In these specimens, nanoparticles measuring about 10–50 nm in diameter form pseudospheres (lepispheres) of appropriate size to diffract visible light (about 200 nm) in a matrix of less acid-soluble silica particles. When examined with a scanning electron microscope, fresh broken surfaces show no particular organization, but after etching with diluted hydrofluoric acid (10% vol. HF), the microscopic arrangement of spheres is revealed. There is a continuum of structures between opals with and without play-of color. In addition to the role of particle size, rounder spheres with a more organized structure display a more noticeable play-of-color with a wider range of colors.

From SEM and AFM images, it is clear that these newly discovered common opals from Michoacán are built from a random aggregation of small, near-spherical grains, averaging 60 to 100 nm in size. (The software we used was ImageJ, an open-source image processing program designed to generate scientific multidimensional images.) The apparent diameter of some grains actually ranges from about 120 to 130 nm (figures 2 and 3). The nanostructure of this common opal explains the absence of play-of-color. In this case, we can consider the following general explanations for the lack of play-of-color:

  The spheres do not have the same size (heterogeneous structure).
  The spheres are not perfectly spherical.
  The spheres are the same size but not well organized.
  The spheres are too small (<150 nm) or too large (>300 nm) to diffract light.

Figure 2. SEM image of the heterogeneous nanostructure of a common gem opal
from the Cuitzeo area in Michoacán. The spheres are too small, irregularly sized,
and disorganized to exhibit play-of-color.

Figure 3. Distribution of particle sphere diameters in the nanostructure of the newly
discovered Mexican volcanic opal. Most of the spheres are 60–100 nm, a size too
small to diffract light.
In some cases two or more of these conditions occur in the same sample.

All Mexican volcanic CT-opals have similar Raman spectra characterized by a very strong general band (apparent maximum toward 325 cm–1) that shows a complex structure with lines of weak to medium intensity (M. Ostrooumov et al., “Spectres Raman des opales: aspect diagnostique et aide a la classification,” European Journal of Mineralogy, Vol. 11, No. 5, 1999, pp. 899–908). According to theoretical calculations, the normal modes in the 300–350 cm–1 range consist mainly of Si-O-Si bending vibrations of ring atoms. Other principal bands in the Raman spectra of opal from these new deposits are found at about 800 and 960 cm–1, 1069–1086 cm–1, and 1600 and 3200 cm–1. These bands belong to α-tridymite, α-cristobalite, α-quartz, and groups of H2O and OH.

Infrared absorption bands were observed between 4000 and 400 cm–1, which is typical for all varieties of micro- and non-crystalline opals (C, CT, and A). The three strong bands near 1100, 790, and 480 cm–1 are common to all silicates with tetrahedrally coordinated silicon (M. Ostrooumov, “A Raman, infrared and XRD analysis of the instability in volcanic opal from Mexico,” Spectrochimica Acta, Part A, Vol. 68, No. 4, 2007, pp. 1070–1076). Broadly speaking, in opal-CT only localized Si-O-Si stretching and bending vibrations remain. The distinction between opal-CT and opal-A requires careful inspection of the frequencies of the three strong Si-O bands. In particular, the band at 790 cm–1 is always at higher frequency in opal-A than in opal-CT. Broad absorption bands between 3700 and 2700 cm–1 are due to fundamental O-H stretching vibrations. For example, a very broad band is present at around 3448–3458 cm–1, with a shoulder at about 3250 cm–1 that is generally considered to be related to hydrogen-bonded molecules of water.

Based on TEM results, we have been able to prove that the orange to brown bodycolor of Mexican common opal is due to nanoinclusions of an iron-containing material. It is probably related to hematite, which is often found associated with common opal in nodules. It typically appears as needles measuring 10 to 20 nm wide by 100 to 200 nm long, seen only with TEM. Source: GIA @topic:11


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. Source: GIA @topic:8


Title: Book Review: Secrets of the Gem Trade, Second Edition Abstract: By Richard W. Wise, hardcover, 404 pp., illus. publ. by Brunswick House, Lenox, Massachusetts, 2016, $99.95.

The gem and jewelry industry is still extremely secretive, even in our fast-paced digital era. In both the first and this second edition of Secrets of the Gem Trade, Richard W. Wise targets trade secrets that almost all beginners and consumers would like to peek into. With over 30 years of experience in the industry, Mr. Wise shared both his knowledge and life experience with his readers in this marvelous work.

Since Wise was not born into the trade—he started out as an apprentice goldsmith, becoming a well-known gem businessman—his personal experience will echo with many readers of this book. His book has been expanded since the first edition was published in 2002. The second edition builds on the author’s research and personal excursions to gem sources, manufacturer hubs, and major markets around the globe. This effort is well reflected in the sophistication of content in many chapters. Wise incorporates important, newly discovered gem sources, including East African ruby deposits. Wise also provides updates on sources that used to be important but have since been exhausted. As a result, the author almost completely rewrote the ruby, sapphire, and spinel chapters in order to deliver the most updated information to the readers.

Wise also added chapters on jade, natural nacreous pearls, conch pearl, demantoid garnet, peridot, moonstone, and sunstone. There is also an introduction to go together with each of the above gems (with the exception of demantoid garnet). A new introduction of blue white diamonds was also included with this update. I paid special attention to the new jade chapter, as Wise went to China’s jade manufacturing centers to experience their treatment of this gem in person.

The first seven chapters of the book introduce the essentials of connoisseurship. The discussion begins with the history of the precious gem concept and the modern concept in comparison. Then it moves to the address several pillars of the modern gem and jewelry industry including grading standards, color description, grading special cases, gemstone enhancement and an overview of new gem sources. Beginning with chapter 8, each chapter deals with one specific gem variety. For gems falling into the same group, the author also provides an introduction before providing an in-depth look at each material. For example, there is an introduction for pearls which is followed by four separate chapters devoted to different varieties.

While this book can be used as a gemology textbook, it is also quite different than those traditionally used for this purpose. The order of the chapters on individual gem varieties follows the alphabetic sequence rather than mineral classification. This makes it a lot easier for readers with no mineralogy background to navigate. Second, the author uses understandable language, rather than scientific terminology, to deliver the message to readers of all different levels and interests. When explaining concepts, personal understanding is always described to add the author’s personality to the content. For instance, in the “Rethinking of 4Cs” chapter, the author explained the standardized 4Cs and then added his own 5th C, “crystal,” an interesting concept that people won’t be able to find in gemology textbooks. Last but not least, this book is well illustrated with breathtaking images and deliberately designed graphics, an aspect that is often lacking in conventional gemology textbooks.

Readers will not just learn the essential concepts of modern gemology, but will also get a better understanding of the gem market. Additionally, the author also uses his own experience to tell the readers what is the best way to learn the gem trade, giving and what “homework” they need to do before going out to buy. It is a good read for people who are currently outside of the trade but want to step in. It is also an excellent review for those who are already experienced in this trade. The second edition of Secrets of the Gem Trade is definitely one of the best comprehensive gemological publications you can find today. Source: GIA @topic:7


Title: Pre-Holiday Gem Orders ‘Encouraging,’ Mixed Results for Auctions Abstract: The 2.11 ct Argyle Everglow is the largest Fancy red diamond ever sold by Argyle at its yearly tender sales. The Everglow was the cornerstone of Arglye’s 2017 Pink Diamond Tender that consisted of 58 stones totaling 49.39 cts. Photo courtesy of Rio Tinto/Argyle

Diamond and gemstone dealers report that pre-holiday orders from U.S. and Chinese retailers are “encouraging,” with good demand for affordable qualities and higher-end stones. Requests for so-called “bread and butter” middle-quality goods are also improving after sagging for the past several years.
In the U.S., diamond traders reported that orders began to pick up in late November as retailers gained confidence in Christmas season sales. Diamonds from a half to two carats were moving well in the mid-quality ranges and affordable colored gems in fashionable settings are popular. Tiffany & Co., which reported a small increase for the third quarter, is predicting a modest single digit sales increase for the season. Signet Group, however, is predicting a single digit decline as consumers are trending away from shopping malls.
Black Friday weekend and Cyber Monday online sales were strong from retailers in general. The National Retail Federation reported that the average spend was up 15% and analysts say online purchases are running at record levels. Most retail jewelers, however, do a majority of their Christmas sales in the week before the holiday.
In China, the world’s second largest diamond and gemstone market, retailers reported the first upward trend in sales in two years, with Chow Tai Fook and Luc Fook registering strong gains.
PINK DIAMOND TENDER
Argyle reported (undisclosed) record prices for diamonds in its annual pink diamond tender, which featured 58 polished red, pink, violet and blue diamonds. The “Argyle Everglow,” a 2.11 ct Fancy red, the cornerstone of the collection, was purchased by David Shara of Optimum Diamonds in New York. Graff acquired the 2.42 ct pink Avaline diamond, the largest stone.
While the prices in the 2017 edition were strong, many of the diamonds from the 2015 and 2016 Argyle tenders are still with their original buyers.

The 14.93 ct “Pink Promise” Fancy Vivid pink diamond sold at Christie’s Hong Kong for $32.16 million on Nov. 28. The $2.15 million per carat price was a record. Photo courtesy of Christie's Images.
AUCTIONS
The first major auctions of the fall season produced decidedly mixed results.
At Sotheby’s Nov. 15 Geneva sale, several top gems went unsold. The 37.3 ct “Raj Pink” was the largest pink diamond ever to come up for auction, but buyers showed little interest and bidding stopped at less than half its top estimate of $29 million. A 7.41 ct Fancy Vivid blue diamond also failed to meet its reserve, as did the Donnersmarck diamonds, a pair of Fancy Intense yellow gems with European royal provenance.
The two bright spots at Sotheby’s were a 33.63 ct Fancy Light pink diamond from Winston that drew a high bid of $12.8 million and a 18.86 ct Burmese ruby ring that sold for $5 million.
The story was much different at Christie’s a day earlier. The top lot was the well-publicized “De Grisigono Creation 1,” an emerald and diamond necklace featuring a 163.41 ct D fl rectangular cut diamond pendant that went for $33.7 million. This was the most expensive D flawless diamond ever sold at auction, according to Christie’s vice president, Francois Curiel.
That diamond was cut from the 404 ct. “February 4” rough found at the Lulo Mine in Angola in 2016. The record price works out to $209,000 per carat, which was much higher than most large D flawless diamonds have been getting in the past year, though nowhere near a record. The high per carat price was notable because the loftiest bids usually go toward faceted shapes – ovals, rounds, etc.
At the same sale, “Le Grand Mazarin,” a 19.07 ct Fancy Light pink diamond, went for $14.46 million. The diamond had been part of the French crown jewels.
Another major fancy pink diamond, the 14.93 ct GIA-graded Fancy Vivid pink “Pink Promise” sold at Christie’s Hong Kong for $32.16 million on Nov. 28. The $2.15 million per carat price was a record. At the same auction, a jadeite, ruby and diamond necklace went for $12.3 million and an 8.8 ct Fancy Intense pink diamond sold for $9.7 million.
On Dec. 5, a 5.69 ct Fancy Vivid blue diamond drew a winning price of $15.1 million ($2.7 million per carat) at Sotheby’s New York sale. A 110 ct. L color, VS1 clarity, which Sotheby’s claimed was the largest round brilliant cut ever offered at auction, failed to sell.
MINE FINDS
It’s been a good month or two for mining 100-plus carat diamonds.
Alrosa’s Jubilee pipe yielded a 108.34 ct yellowish diamond and a 163.11 ct colorless stone. It also found an 82.8 ct gem, also yellowish.
In Sierra Leone, a small mining company unearthed a 476 ct stone in the country’s Kono area, its primary diamond producing locale. Earlier this year, a digger discovered a brownish 709 ct diamond that Rapaport auctioned on Dec. 4 for $6.5 million ($9,167 per carat) in New York. The buyer, London jeweler Laurence Graff, said the proceeds from the stone will be used to help some of the poorest people on Earth. About $1.1 million from the sale will be distributed to local diamond diggers in the district where the diamond was found.
Lucapa Mining in Angola reported finding a 129.58 ct diamond in early November and Gem Diamonds, a majority owner of the Letseng Mine in Lesotho, has discovered six 100-plus carat diamonds through the first nine months of the year. Source: GIA @topic:8


Title: Book Review: Van Cleef & Arpels: The Art and Science of Gems Abstract: By Alvin Pang, Laurence Mouillefarine, Bérénice Geoffroy-Schneiter, Adriano Davoli, Timothy Adams, Vivienne Becker, Alberto Cavalli, Laurence Benaïm, François Farges, hardcover, 295 pp., illus., publ. by Éditions Xavier Barral, Paris, France, 2016, $75.00.

	This exquisite collaboration memorializes the bespoke mid-2016 exhibition of more than 400 pieces of Van Cleef & Arpels jewelry at the ArtScience Museum in Singapore, a collaboration with the French National Museum of Natural History.

	Covering more than a hundred years of the maison’s jewelry prowess, the book is divided into sections on artistry, influences, abstractions, couture, precious objects, nature, ballerinas and fairies, minerals and gems, and icons.

	Each section is introduced by one of the book’s nine contributors, comprising a formidable powerhouse of jewelry historians, curators, scientists, scholars, and writers. The editorial content, concisely organized using an expanded bullet-point structure, is crisp and coordinated. Each contributor illuminates the breathtaking images by providing historical context, scholarly sensitivity, and insight.

	Integrated with stylistic consistency are the impeccable photographs by Patrick Gries and other contributors, dramatically casting the jewels against a black background laced with billowing, wispy trails of gray. Images from the National Museum of Natural History in Paris, a collection that demands inclusion on every serious gemologist’s bucket list of must-see treasures, provide a geoscientific core to the book, with Earth serving as a “giant atelier.”

	An appendix offers the essential chronology of the house, tracing the 19th-century family ties that led to its Place Vendôme founding in 1906, along with photographs of trailblazing members of the multigenerational families.

	Most pages are filled with individual photographs of the maison’s jewelry in its splendor. Chosen from the collections of Van Cleef & Arpels and private collectors, the pieces glow in a peerless range of style, exoticism, and innovation. Magic, mystery, and mastery are all at work here, with clips, zip necklaces, bracelets, minaudières, vanity cases, and assorted objets d’art showcasing the house’s landmark mystery, or invisible, setting (patented in 1933); hidden watches; magic clasps; the transformable jewel known as the Passe-Partout; and novel materials such as Styptor, an alloy of pewter and silver.

	The private collection includes jewels of towering significance, provenance, and fortune, whether commissioned by South Asian maharajas or royals hailing from the Middle East to Monaco. These remarkable pieces were collected by heiresses and magnates of the early 20th century, such as Daisy Fellowes and Barbara Hutton; others later adorned mid-century style icons Elizabeth Taylor and Jacqueline Kennedy Onassis and artists like Maria Callas. The house also inspired another type of enduring art—ballet—as in the George Balanchine and Claude Arpels–choreographed “Jewels,” another de rigueur experience for the gem-obsessed.

	Jewelers, designers, historians, and aesthetes will treasure the mastery and magnificence of the works shown on these high-quality finely pearlized pages. Readers flocking to this book for its artistry and beauty will be amply rewarded, and the ingenuity and craftsmanship of Van Cleef & Arpels offer many happy returns, if not a degree of solace for missing the Singapore exhibit. Source: GIA @topic:6


Title: Book Review: Gem: The Definitive Visual Guide Abstract: Foreword by Aja Raden, hardcover, 440 pp., Dorling Kindersley, New York, 2016, $50.00.

	The first edition of Gem: The Definitive Visual Guide is a visual encyclopedia driven by spectacular images of world-class gems, artifacts, and jewels. Developed in association with the Smithsonian, with a foreword by jeweler and scientist Aja Raden, the book is a good resource for amateur to professional gemstone lovers.

Gem starts with an introduction to basic concepts of geology and mineralogy, the roots of modern gemology. It then moves to more specific descriptions of gemstone resources, mining, manufacturing, evaluation, and the concept of a jewel. The introduction is a quick reference for readers without a science background or familiarity with the gem and jewelry industry.

	The main body of the book is divided into “Native Elements,” “Gemstones,” “Organic Gems,” and “Rock Gems and Rocks.” These titles are commonly used in comprehensive gemology publications and textbooks, but here the items under each one do not follow the standard alphabetical mineral list. “Native Elements” covers precious metals and diamond, though diamond is typically considered a gemstone. The famous Hope diamond is also described here.

	The other three sections also introduce both gem species and special single stones. Images illustrate each gem species, rough stone, polished or faceted stone, and jewelry piece. The physical properties of each are also listed. Famous crown jewels, appealing artifacts, and jewels of significance or owned by historical figures or celebrities are detailed. From Byzantine to ancient Egyptian jewels, from the Maharaja of Patiala’s diamond and ruby necklace to the Chinese luxury birdcage of the Qing dynasty, and from King Ludwig II’s gold pocket watch to the Duchess of Windsor’s Cartier flamingo brooch, readers can not only learn the basics of gemstones but also enjoy a visual tour of jewelry history.

	The jewels and artifacts are illustrated by high-resolution images and historic paintings. Some are even accompanied by a timeline tracing their history, as with the Crown of the Andes, for example. From around 1500, when the center emerald was attained, to 2015, when the crown was sold to the Metropolitan Museum of Art in New York City, it has been gradually modified and changed owners. These stories could lead the readers to more in-depth research on certain items.

	The last hundred pages of the book are devoted to several very useful tools, including a color guide, a mineral and rock directory, a glossary, and an index. The mineral and rock directory is very handy for professionals for quick fact checking. The color guide and the index can help readers easily find related content in the book, while the glossary provides brief definitions of important concepts and terms.

Gem is a very visually appealing work and a good choice for any gemology or jewelry book collection. It would also be a meaningful gift for gem and jewelry lovers. Source: GIA @topic:7


Title: GIA Hosts Alumni Events, Displays at Tucson 2017 Gem Shows Abstract: Alumni from around the world joined the 2017 “Party at the GIA Gem Mine: Cosmic Blast.” Most, including Peter Gruhl and Vicki Martinez, stopped at the photo booth before entering the party. Photo by GIA

	An out-of-this world photo experience, starship-like entryway and starry lights set the stage for the 2017 “Party at the GIA Gem Mine: Cosmic Blast,” but the pure joy and comaraderie as alumni greeted one another was the highlight of the annual dinner-dance and auctions. More than 350 guests from 15 countries (the U.S., Brazil, Canada, Columbia, China, Japan, Germany, Myanmar, Malta, Italy, South Africa, England, Thailand, India and more) attended the most fun party in Tucson.

	The event is an opportunity to connect with former classmates, meet new industry friends and perhaps establish a new business relationship.

	This year, it was also an opportunity to celebrate the 35th anniversary of the GIA Alumni Association that Richard T. Liddicoat and Robert Earnest established in 1982. Liddicoat and Earnest recognized the benefit of organizing GIA graduates around the world to encourage and promote the shared interests, education, news and business networks that support integrity and knowledge in the gem and jewelry industry. Today, the organization is more than 116,000 members strong with 70 chapters around the world.

Shauna and Starla Turner show off − Vanna White-style − items during the live auction so the audience can see them up close. Shauna, left, is holding a signed copy of the new GIA "Micro-Features of Emerald" wall chart from the Winter 2106 issue of G&G. Signed by GIA authors: Nathan Renfro, John Koivula, Jonathan Muya, Shane McClure, Kevin Schumacher and Dr. James Shigley. Starla is carrying a GIA PresentationScope. Photo by GIA

	Beyond catching up with old friends, this alumni event is an opportunity to support the Alumni Endowment Fund. This year’s event raised more than $25,000 from event tickets and the auctions. Seventy items (including loose gemstones and pearls, designer jewelry, mineral specimens, equipment, books and more) were available to bid on. Joseph DuMouchelle and Lindy Adducci, of DuMouchelle Auctions, volunteered their professional services – for the 16th year – to run the exciting live auction.

	“A special thank you to all our auction contributors, supporters, event volunteers and attendees,” said Kate Donovan, GIA manager of global alumni relations. “We look forward to seeing you all next year − and we’re already accepting auction donations!”

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	Alumni Leadership Breakfast

	GIA Alumni Association chapter leaders and senior GIA executives also gathered in Tucson for a leadership forum to discuss chapter ideas, challenges, policy and plans. This annual event makes it possible for attendees to share and coordinate ideas and enhance relationships between chapters for the overall benefit of the alumni association.

	More than 30 alumni leaders from 22 chapters (the U.S., Canada and Germany) attended along with GIA executives Susan Jacques, president and CEO; Bev Hori, senior vice president of education and chief learning officer; Susan Schindelar, vice president of global marketing; Stephen Morisseau, director of corporate communications; and Danae Brooker, director of branding.

	Kate Donovan kicked off the discussion by sharing the variety of GIA materials and programs available to alumni chapter leaders to share at meetings, including the GemKids website, Retailer Support Program, Continuing Education Recognition Program and scholarship information.

	Starla Turner, a longtime alumni leadership council member and past-president of CA – Golden Gate chapter, kicked off a chapter-to-chapter peer discussion that included tips on the best ways to run chapter events, find meeting topic ideas and engage more alumni with local chapters.

Show attendees were able to learn more about synthetic diamonds in an exhibit that displayed them side-by-side with natural diamonds. Photo by Amanda Luke/GIA

	GIA Displays

	The GIA museum and the Richard T. Liddicoat Library and Information Center had exhibits during the gem shows.

Synthetic Diamonds at AGTA

	Synthetic diamonds grown by the HPHT and CVD methods have become more prevalent in the jewelry trade. The Institute – which can identify all known types of synthetic diamonds – displayed a variety of samples including large colorless and colored rough HPHT, large colorless and colored faceted HPHT, rough CVD, faceted CVD, rough HPHT melee, and faceted HPHT melee diamonds side-by-side with natural diamonds at its booth on the Galleria level.

The Fersman Catalog at TGMS

	The GIA library’s copy of Russia’s Treasure of Diamonds and Precious Stones by A.E. Fersman is one of the few surviving examples of a Bolshevik-era catalog of royal jewels seized during the Russian Revolution. The library featured a special display at TGMS dedicated to the catalog, including an historical figure of Catherine the Great by George Stuart (on loan from the Ventura County Museum of Art) and replicas of notable diamonds, the Orlov and the Shah.

Turquoise measuring 39.5 x 24 x 10 cm is part of the GIA museum exhibit “Highlights of the Hauser Collection.” Photo by Orasa Weldon/© GIA

Highlights of the Hauser Collection at TGMS

	GIA’s museum recently acquired a collection of ornamental minerals of exceptional size and quality, made possible through a generous donation by the family of Joel and Barbara Hauser. Many of the pieces are from localities with restricted access or that are no longer producing. Attendees of TGMS had the opportunity to view 13 of the finest pieces from the Hauser collection as part of a special exhibit. Source: GIA @topic:9


Title: Book Review: Gems & Crystals: From One of the World’s Great Collections Abstract: By George E. Harlow and Anna S. Sofianides, with photography by Erica and Harold Van Pelt, hardcover, 232 pp., illus., rev. edition publ. by the American Museum of Natural History with Sterling Publishing, New York, 2015, US$27.95.

	This volume is a pleasing combination of coffee-table book, reference book, and guide to a museum collection. It is the 25th anniversary revised edition of the authors’ Gems and Crystals: From the American Museum of Natural History (1990). There is a certain sense of continuity conveyed by having the same authors still working in the field adding to the collection and knowledge base.

	The introduction details the notable acquisitions, sponsors, and curators over the years. It all started with the collection assembled by George Frederick Kunz in 1889, financed by John Pierpont Morgan. The department was expanded in the 1970s and renamed the Department of Mineral Science, and in 1995 it became the Department of Earth and Planetary Sciences, which includes minerals, gems, and meteorites. Of the 110,000 minerals and 4,500 gems total, 1,800 are on display in the Morgan Hall of Gems and 2,600 in the Guggenheim Hall of Minerals. A much larger percentage of the gems are on display because they tend to be more visually interesting. The stored collections, however, are a tremendous resource for scientific data gathering.

	Part One, “The World of Gems,” gives a very brief history of gems, highlighting the fact that the use of stones for personal adornment can be traced to 25,000 BCE. Through archeological findings and historical texts, it has been determined that there was early interest in the scientific properties of gemstones and not just their beauty or use as amulets. It goes on to describe very basic crystallography concepts and physical properties such as pleochroism and fluorescence, using well-known gems as examples. The writing is clear and not overly technical. Formation and quality factors are briefly addressed. The sections on synthetics, simulants, and enhancements are also brief and do not cover the myriad topics within.

	Part Two, “Gallery of Gems & Crystals,” represents the bulk of the book and delves into the details of specific gemstones. It starts with the most commercially significant and well-known: diamond, corundum, and beryl. The format includes a small information box of properties and sections on history and lore, sources, value factors, and specific examples in the AMNH collection. The accompanying photos show the range of colors and phenomena, rough and jewelry examples, historical illustrations, and specimens from the museum.

	The section on diamonds includes updates since the 1990 edition for new mining areas, the advent of the Kimberley Process, and synthetic diamonds production by the CVD method. But it neglects to indicate that high-pressure methods are still widely used and have been optimized. Since synthetic diamonds are a hot topic for consumers, it would have been helpful to mention the colors and sizes now attainable. Irradiation is mentioned, but not multistage treatments with irradiation plus HPHT treatment.

	In the corundum section, when discussing the benefits of heat treatment, the authors quip, “We could heat the Star of India [the museum’s most famous gem, a 563.35 ct gem-quality star star sapphire] and create a fabulous blue cabochon—perish the thought!” Seasoned gemologists will pick up on the inconsistencies related to padparadscha sapphire—described as “orange” on p. 37 but referred to five pages later as pink-orange and orangy pink (though the famous 100 ct Sri Lankan example shown does look too orangy). And even though there are numerous treatment processes for corundum, only heat treatment is mentioned.

	Paraíba tourmaline is given short shrift, only noted as a highly valued blue-green color variety but not highlighted as a recent find, with unique coloration and limited sources. Most disappointingly, it is not illustrated. Perhaps there have been no donations of this fabulously expensive gemstone? There is an interesting comment on the pyroelectric effect that causes the tourmalines in the AMNH collection to attract dust under the heat of the display lights, something that observant museum-goers would notice.

	Although the sections are brief, there are interesting tidbits to spark the reader’s interest and understanding: for instance, the observation that treated zircon was commercially available and accepted as early as the 1920s, or that turquoise is the most widely imitated and treated of all gems.

	The chapter on jade does skillfully distinguishes nephrite, jadeite, and omphacite, highlighting the huge boulder on display at the museum.

	In the section on organic gems, pearls, coral, amber, and jet are covered. The pearl section is a bit brief, considering what is widely available to consumers. Only saltwater pearls are mentioned as cultured, overlooking the enormous significance of freshwater cultured pearls made by bead, tissue nucleation, and other rapidly evolving techniques. Other pearl types that would be of great interest to amateurs, such as conch or clam pearls, are not mentioned.

	In the last section, on rare and unusual and ornamental materials, the authors acknowledge their own biases in ranking the gems in descending order of quality. Zoisite has been given just one paragraph and an illustration of a rough crystal. Tanzanite has become so mainstream that it need not be relegated to the “rare and unusual” section.

	The book ends with a glossary and an annotated reading list. I heartily agree with the list of 25 books, journals, and websites, as it resembles my own core collection.

	A good balance is struck between illustrations of rough, exemplary crystal specimens, faceted specimens, and historical illustrations and jewelry. The biggest disappointment in this book is the quality of the photos. The Van Pelts are legends, but the quality of film photography from 1990 cannot compete with quality of digital photography today. That, coupled with the difference in technology of color reproduction and printing, leaves some photos lacking depth or brilliance. They are simply not up to contemporary expectations.

	This book goes well beyond its purpose as an introduction to the museum’s collections and a basic primer on the geology of gemstones as well as the jewelry arts. It is eminently readable and draws the reader into the fascinating world of gemology. It would be useful in a professional environment where one could use the information in the “Historic Notes” and “Legends and Lore” sections to add color to a presentation. The “Evaluation” section serves as basic guidance and a starting point for budding collectors. Some information in “Occurrences” is not up to date, which is understandable given that colored stone mining sites tend to be small and can shift within months. Nevertheless, this book stands on its own as a reference book or—if one is fortunate enough to visit the AMNH in New York—a wonderfully readable guide to the museum’s collection. Source: GIA @topic:1