# Publication Year: 2023
# Title: Fine Linear Structures in Non-Bead Cultured Pearls
# Abstract: Four non-bead cultured pearls (samples 1–4, left to right) weighing 0.22 to 4.84 ct. Photo by Gaurav Bera.
Saltwater non-bead cultured (NBC) pearls are defined by the World Jewellery Confederation (CIBJO) as those without an internal bead nucleus that have “formed accidentally or intentionally by human intervention in marine pearl oysters.” These are commonly referred to as “keshi” pearls in the trade. GIA’s Mumbai laboratory has received many pearl submissions that revealed internal structures typical of NBC pearls such as large voids, elongated linear structures, and some with loose concentric “gaps.” However, a recent submission of 23 loose pearls for pearl sorting service proved quite challenging to identify. Externally, all of them looked similar, with a white to light cream color and a medium to high luster. Some possessed a few surface blemishes, but on the whole they were quite clean and appeared cultured.
A majority of the pearls in the lot exhibited concave bases, while a few showed bases with concentric, graduating white to cream-colored rings, with distinct central white frosty patches which were part of the inner subsurface nacreous layers. Four pearls revealing different forms of linear structures were selected from this lot. All were white and button shaped, with sizes ranging from 3.24 × 2.55 mm to 10.33 × 6.84 mm (see above). Externally, all their surfaces exhibited typical nacreous overlapping aragonite platelets, with a fingerprint-like pattern when viewed under 40× magnification.
Energy-dispersive X-ray fluorescence spectrometry on the four pearls revealed low manganese levels ranging between 12.60 and 41.10 ppm and high strontium levels between 1767 and 2883 ppm. Additionally, optical X-ray fluorescence analysis yielded an inert reaction, thus confirming their saltwater origin. The pearls showed a moderate bluish green reaction when viewed under long-wave ultraviolet radiation and a weaker bluish green reaction under short-wave ultraviolet radiation. Raman analysis using 514 nm laser excitation showed a doublet at 702 and 705 cm–1 and peaks at 1085 and 1463 cm–1 indicative of aragonite.

Real-time microradiography (RTX) and X-ray computed microtomography (μ-CT) analysis revealed internal structures that were not straightforward and required more work to reach conclusive results. RTX imaging of pearl 1 showed a prominent, very fine central linear feature horizontal to the base (table 1, row 1). Analysis with μ-CT revealed a more obvious linear feature showing that it was unaligned with the other growth arcs that generally followed the shape of the pearl. This structure was observed in most of the samples in the submitted lot. Externally, a small white frosty central spot was visible on the concave base surrounded by graduating circular rings.
RTX images of pearl 2 revealed a small circular light gray core associated with undefined gray arcs curving along the core in a distorted pattern (table 1, row 2). Moreover, only a couple of weak growth arcs were observed in the outer nacre layers. The structure was very similar to those observed in some natural pearls with small dense cores, making it inconclusive (A. Homkrajae et al., “Internal structures of known Pinctada maxima pearls: Cultured pearls from operated marine mollusks,” Fall 2021 G&G, pp. 186–205). Further μ-CT analysis helped define the main feature, a short and fine linear structure accompanied by a minute void-like feature.
RTX images for pearl 3 revealed a medium-size button-shaped central organic-rich core, which was radiotranslucent and had a thin gray outline (table 1, row 3). This was surrounded by numerous fine growth arcs that followed the shape of the core. Although this organic-rich core looked quite natural from the RTX images, μ-CT images revealed a short linear feature in the center of the core, suggesting an NBC pearl.
The largest sample, pearl 4, had been partially drilled, and the drill hole was quite large (table 1, row 4). It was unlike the thinner and shorter drill holes often used for weight retention in natural pearls. While the choice of drill hole thickness is not decisive evidence on its own, it may be a useful indicator (Spring 1986 Lab Notes, pp. 51–52; Summer 1986 Lab Notes, p. 111). Externally, the pearl had a rounded base and a circled circumference with multiple deep indentations associated with the circled grooves. The RTX images showed minute metal remnants (visible as radiopaque white specks) within the drill hole and extensive curved growth arcs throughout the pearl, with additional arcs located on adjacent boundaries. The pearl showed minimal tight growth structure, and its external appearance aroused suspicion. Further examination via μ-CT analysis revealed a small linear feature that had been partially removed by the drilling. Reaching a conclusion would be very challenging, if not impossible, using RTX analysis alone.
Given the volume of button-shaped pearls the Mumbai laboratory has been testing, it is quite evident that large quantities of such pearls are circulating in the market. These pearls mostly have smooth surfaces and high untreated luster. The linear features could not be identified in all the pearls using RTX alone due to a number of factors including size, appearance, radiotranslucency, and orientation. It is not difficult to remove minute linear structures by drilling, and such pearls could easily be passed off as natural due to the presence of fine growth features around the center. But with the availability of advanced technology, especially μ-CT imaging, remnants of the linear structure were evident in certain orientations. In some cases, with the proper alignment of the drill hole, such small linear structures may also be visible in the RTX images. This requires considerable skill and patience to align, starting from the thickest direction first with respect to the shape of the pearl and then repositioning the same pearl 90° in the profile view. Therefore, it may be risky to rely on RTX results alone (S. Karampelas et al., “X-ray computed microtomography applied to pearls: Methodology, advantages, and limitations,” Summer 2010 G&G, pp. 122–127).
By analyzing these challenging internal structures using modern equipment, GIA and other laboratories aim to protect consumers by creating awareness of them and minimizing the chances of misidentification. @chapter:11 @chapter:4 @chapter:11


# Publication Year: 2016
# Title: Natural Colorless Type IIa Diamond With Bright Red Fluorescence
# Abstract: Figure 1. This 0.40 ct, D-color type IIa round brilliant diamond showed very bright red fluorescence due to strong emission peaks from the nitrogen-vacancy centers. Photo by Nuttapol Kitdee.

The nitrogen-vacancy (NV) center is produced in nitrogen-bearing diamond through the combination of a single nitrogen atom and a vacancy. It can exist in neutral (NV0) and negatively charged (NV–) states. Using photoluminescence (PL) spectroscopy, NV centers can be detected by the occurrence of zero-phonon lines (ZPL) at 575 nm for NV0 and 637 nm for NV–. In natural type IIa diamonds, the emissions of NV centers are usually weak, and the relative intensity of NV0 (575 nm) is typically stronger than that of NV– (637 nm). As a result, the vast majority of natural type IIa diamonds show blue fluorescence, attributed to the occurrence of defects such as N3 or dislocations, when excited by the short-wave UV radiation of the DiamondView. Recently, however, the Bangkok laboratory examined a natural colorless type IIa diamond that showed very bright red fluorescence due to high concentrations of NV centers.

This 0.40 ct round brilliant diamond received a D color grade and an SI1 clarity grade based on surface-reaching fractures at the girdle and on the pavilion (figure 1). The infrared absorption spectrum confirmed a type IIa diamond with no measurable defect-related absorptions. Microscopic examination with cross-polarized light revealed a relatively strong tatami strain pattern with a weak interference color (figure 2). Further examination with the DiamondView showed that this stone exhibited an unusual red fluorescence (figure 3), similar to that of nitrogen-doped CVD synthetic diamonds. However, the DiamondView images revealed dislocation networks of typical natural type IIa diamond along with a tree-ring growth pattern, which is very rare for natural type IIa diamond but typical for natural type Ia diamond.

Figure 2. Viewing the diamond under cross-polarizing filters revealed a tatami strain pattern with a weak interference color, a characteristic of natural growth. Photo by Charuwan Khowpong; field of view 3.1 mm.

Figure 3. DiamondView images of the 0.40 ct diamond showed red fluorescence, which is unusual for natural type IIa stones. This red fluorescence was related to the intense emissions of the NV centers. Also observed was a dislocation network typical of natural type IIa diamond, along with a tree-ring growth pattern. Photo by Wuyi Wang.
In order to detect any possibility of treatment, we employed PL spectroscopy at liquid nitrogen temperature with several laser excitations. With 514 nm laser excitation, the PL spectrum revealed very strong emission peaks from NV0 (575 nm) and NV– (637 nm) (figure 4). This is very rare in natural type IIa diamonds. The higher intensity of the NV0 emission was observed. For this diamond, short-wave UV excitation close to 230 nm was very effective in exciting fluorescence from the NV–, which has a ZPL at 637.0 nm and its strong side bands at longer wavelengths. Due to the relatively high concentration of the NV– defect, strong red fluorescence was observed.

Figure 4. The photoluminescence spectrum at liquid nitrogen temperature using 514 nm
laser excitation displayed strong emission peaks at 575 and 637 nm due to NV0 and
NV– centers, respectively. In natural type IIa diamonds, the intensity of NV centers is
usually weaker than the diamond Raman peak at 552 nm.
Both spectroscopic and gemological features clearly indicated a natural diamond. The excellent color and the red fluorescence, which is rare for a natural colorless type IIa diamond, make this a notable stone. @chapter:22 @chapter:1 @chapter:22


# Publication Year: 2016
# Title: Book Review: The Classic Goldsmith
# Abstract: By Mark Maxwell, softcover, 122 pp., illus., publ. by Maxwell Press, Oceanside, CA, 2015, US$29.95.

Benchie… Do you know that term? Well, this is a great little book, by a benchie, for benchies. That doesn’t mean you can’t appreciate it if you aren’t one, but it’s really geared to that demographic. By the way, benchie is an affectionate name for bench jewelers: the folks who take bits and pieces of precious metals and some gemstones and work their magic to create the wonderful delights of ornamentation we call jewelry. They’re also the ones who will take in a treasured jewelry heirloom that has seen better days, and they’ll either breathe life back into it or transform it into something completely new.

	What this book is not: It is not quick and easy, comprehensive, exhaustive, encyclopedic, the beginner’s guide to anything, or a coffee table edition. So how can I call it a great little book? It’s a bit like the old-time baseball player with the high batting average whose motto was, “Hit ’em where they ain’t.” There are numerous books about jewelry that fit into the above categories, but the field is much more open for a book full of projects for intermediate to advanced jewelers, and this is where it shines.

	The book is a collection of projects that were originally published by Mark Maxwell in MJSA Journal’s “At the Bench” column over a period of years. As a trade publication published by Manufacturing Jewelers and Suppliers of America, it is clearly aimed at insiders. This collection is not a simple reprint, though. This well-illustrated, self-published effort (available through Amazon.com) has expanded upon those articles and added more in-depth instructions and insights.

	Organized into seven chapters of increasing complexity, from sawing and filing to metal inlay and even CAD, it is a guide to instruct you through a range of projects, and also a nudge to go beyond the project at hand. Thinking ahead, planning the work, and precision and accuracy are repeatedly emphasized, so that finished projects will show to their best advantage and function correctly. The assumption here is that as a bench jeweler, you already know how to use your tools, and these projects will broaden your horizons and stretch your abilities. There are no magical skills required, but you must set your standards high to succeed with these projects. There are also optional workflow suggestions, depending on the availability of some advanced tools such as a laser welder.

	Some projects end up as finished jewelry—rings, pendants, earrings, bracelets, and so forth—while others are exquisitely contrived components such as latches, clasps and hinged mechanisms. Being able to fabricate specialized components such as these is another skill that sets apart a master goldsmith.

	The only thing that would be disappointing would be to see a pristine copy of this book. Don’t get me wrong: I love and collect books of all stripes, but this book is meant to be used. It needs to have smudged margins, some gold and silver filings wedged in the spine, and even a few dog-eared pages. @chapter:25 @chapter:2 @chapter:25


# Publication Year: 2020
# Title: The “Fragility of the Eternal” Kunzite: Origin, Cutting, and Identification
# Abstract: Figure 1. The pronounced pleochroism of the rough spodumene crystal weighing 2,950 grams, seen here in two orientations, was one of the properties that had to be considered during fashioning. Photos by Arjuna Irsutti.
Lapidary, the art of colored stone fashioning, is an art that requires a keen eye, talent, and great patience. Different gem materials have their particular quirks that must be considered when planning the various steps required to reach the ultimate goal of obtaining the most aesthetic stone while usually also optimizing weight yield.
Spodumene is known to challenge even the most experienced cutter owing to its high fragility, perfect cleavage planes, and unpredictability in different cutting directions. This is further magnified when the rough is exceptionally large and the cutter’s goal is to produce the largest faceted kunzite in the world.
This was author VT’s aim as he prepared to work on a piece of rough spodumene that weighed 2,950 g. The untreated crystal (figure 1) originated from Kunar Province in Afghanistan. Although a wide crack was visible at one end and about 30% of the opposite end contained numerous inclusions, the removal of both sections still left more than 1.5 kg of relatively clean rough after 20 hours of wire sawing (the safest method under the circumstances). Since the rough was oversized, some of the routine cutting accessories such as dops and transfer holders, as well as the cutting tactics, had to be adapted for the job.
Prior to the start of the process came the design element. No journey can be completed without knowing the destination, and so rather than playing it safe and opting for a simple design, the artist, VT, chose a truly challenging facet pattern of his own design that incorporated 914 facets. The “Fragility of the Eternal” design is based on the stained glass window of the iconic Notre Dame cathedral in Paris. The stone is the fifth in a series of six cut designs that fall under VT’s “World Heritage” project.
VT would also have to revise his usual strategy due to the size. So instead of cutting the pavilion first, followed by the girdle, crown, and finally the table facet, it was necessary to start with the table facet for this masterpiece. This presented its own challenges since the faceting required specialized equipment belonging to a friend in Moscow. The choice of equipment was also dictated by the material’s fragility and perfect cleavage, which prevented the use of coarse laps. This combined to make the work time-consuming, especially since large facets were the order of the day.

Figure 2. A working diagram showing the facet positions. These helped estimate the final weight of the finished stone before work began on the rough. Photo by Victor Tuzlukov.
The next step required the rough to be rounded in order to achieve the basic outline of the stone in its face-up position. This meant that sufficient pressure had to be applied to the 1.5 kg preform using both hands. Eventually the correct shape resulted. The diameter measured approximately 85 mm, while the table facet came in at 65 mm. This allowed the final weight to be approximated using formulas and the facet plan shown in figure 2. The result, between 2,500 and 3,000 ct, indicated that it would supersede the largest known faceted spodumene, an 1,800 ct green spodumene cut by John Sinkankas in 1959 that was destined for the Royal Ontario Museum in Toronto.
Although the rest of the preforming could not be done traditionally by hand, VT managed to use his faceting unit with custom-made dops provided by his friend and former student Danial Hu. The pre-faceting step took considerable time to complete because the goal was to create an important piece of art and each facet needed to be cut in a pattern that matched the stained glass window in the Notre Dame cathedral with a precision of tenths of a millimeter. Perhaps the most complex part of the process was creating 16 mains and 16 additional lines extending from the center (culet) to the girdle, each containing eight (main) and five (additional) parallel-sided facets, continuous with one another. An equally challenging task was ensuring the proportions were correct while cutting 18 rows of facets of different sizes and shapes, where one often does not depend on another, and finally making the last row of facets correspond exactly with the girdle, which was already pre-shaped. It was impossible to change the width of the final facets without breaking the pattern, which meant that the pavilion had to finish precisely where the girdle started. In other words, the width of all 18 rows had to be exactly proportional to the diagram. Another look at figure 2 is enough to show that the girdle does not simply separate the crown from pavilion as in traditional faceted stones: It is an essential element of the design.
Many chances for something to go awry existed during the cutting process. Only a slight error in judgment or calculation would result in disaster. For example, if the rows of facets were just a bit too wide, there would not have been enough space for the design and the pavilion would have required a complete recut. If some were too narrow, the girdle would have needed recutting, resulting in a smaller stone, which would also have meant recutting the table facet. Fortunately, the final facet positions aligned perfectly around the girdle, and the stone’s final diameter (83.7 mm) was off by just over 1.0 mm from the initial calculations.

Figure 3. The polishing step on the stone’s pavilion begins to show the intricate optical effects of the completed piece. Photo by Victor Tuzlukov.
The next steps, pre-polishing and polishing of the pavilion facets (figure 3), were straightforward in comparison. Yet, as mentioned previously, the sheer size meant that the vertical pressure had to be applied equally over the whole stone during pre-polishing, requiring modification of the technique used for routine work on smaller stones. If too much force was applied to the left or right side, or back and forth, the facets would become too large and the pattern would be broken. To overcome this, the stone’s own weight provided sufficient force on the rotating lap so that the pressure was always equally distributed.
After more than two months of daily work, the pavilion was polished. The next step was transferring the stone to a new dop to polish the crown. Unlike traditional lapidary procedures, directly heating the stone as part of the transfer was not an option, as the process could crack the stone along the twin plane in the direction it needed to be dopped, and because the size was once again a factor when it came to how evenly the heat warmed the stone. This resulted in the application of a technique that the late Jeff Ford from Michigan shared with VT in 2006, using a combination of wax and superglue. The wax is placed on the hot dop, which is softened by the heat. The cold stone is then placed, pavilion first, in contact with the wax, and an impression of the surface is made in it. One drop of superglue is enough to secure the stone firmly in position, and it can be removed by reapplying a little heat to warm the wax again.

Figure 4. The 3,051 ct “Fragility of the Eternal,” containing 914 facets, is believed to be the world’s largest cut kunzite. Photo by Adisorn Wattanavanich.
After three months of work, the final polishing step was completed. The gem’s removal from the dop was an exciting moment, and it was wonderful to finally see the end product in all its glory (figure 4). The finished piece weighed 3,051 ct, very close to the maximum estimated weight of 3,000 ct.
The final step in the stone’s journey was its submission to GIA’s Bangkok laboratory for examination and a report. The gemologists were excited to study such a large kunzite, although the size, 83.75–83.79 × 65.00 mm, presented challenges that limited the testing equipment that could be used. Hence, basic gemological techniques came to the fore, with Raman spectroscopy the only advanced technique used as a final confirmation. The stone was found to be anisotropic with a loupe and microscopic observation up to 70× magnification, and this property was also apparent in terms of the strong pleochroism that could be easily seen as the stone was turned. The same purple and green colors are also clearly evident in figure 1.
The RI readings of 1.660–1.676 (birefringence of 0.016) together with the trichroic colors seen through a dichroscope showed it was optically biaxial. Inclusions such as growth tubes, transparent crystals, negative crystal fingerprints, and a “natural” retained on the girdle all proved the stone was natural. Combined with the weak and moderate orange zoned long-wave ultraviolet fluorescence reaction, the data were consistent with spodumene, kunzite variety.
Since the stone was cut and submitted by VT with a series of photographs documenting this fact, the GIA report (dated May 27, 2020) also mentioned that it was represented as cut by him. Since it was the largest known faceted kunzite examined by GIA at the time, and indeed the largest faceted example of its kind known to exist, a GIA Notable Letter was issued to accompany the report. @chapter:4 @chapter:0 @chapter:4


# Publication Year: 2023
# Title: Tourmaline in Emerald
# Abstract: Prismatic black tourmaline in a Zambian emerald. Photomicrograph by Virginia Schneider; field of view 1.76 mm.
The author recently examined a 3.80 ct emerald with well-formed black, opaque prismatic crystals (see above). The surface-reaching crystals were identified as tourmaline through the use of Raman spectroscopy. While tourmaline crystals are relatively uncommon inclusions, they have been documented in emeralds from Zambia, Pakistan, Russia, and Ethiopia, all of which are schist-hosted deposits. Laser ablation–inductively coupled plasma–mass spectrometry chemical analysis combined with inclusion observation revealed this emerald to be of Zambian origin. @chapter:8 @chapter:0 @chapter:8


# Publication Year: 2020
# Title: Finders, Keepers: Field Trip to Crater of Diamonds, USA
# Abstract: Figure 1. These diamonds from Crater of Diamonds State Park were mined previously by other prospectors. They range up to approximately 0.06 ct. Photo by Roy Bassoo.
There’s only one place on earth where the general public can prospect for diamonds directly from a primary kimberlite pipe: Crater of Diamonds State Park. This park is nestled among the pines, 100 miles off the interstate near the town of Murfreesboro, Arkansas. It boasts a network of scenic walking trails, picnic sites, and campsites. At its Diamond Discovery Center, visitors can learn about the local geology. Staff are also on hand to identify any minerals that are taken home, per their “finders, keepers” policy. The park is an ideal spot for a field trip. The state also hosts many other unusual igneous rocks, including carbonatite, lamprophyre, and lamproite. With this in mind, our university petrology class piled into a van to visit Arkansas and learn about mantle-derived magmas and associated volcanism. As a side quest, we wanted to try prospecting.

Figure 2. Prospecting for diamonds at the Mauney mine, now Crater of Diamonds State Park, circa 1908. Photo courtesy of the Crater of Diamonds Archives.
The park’s main attraction is diamonds, but there are also olivine, pyrope, almandine, and amethyst to be found. Most of the diamonds recovered there are small (approximately 0.20 ct or less); see figure 1. Rarely, prospectors have found stones larger than 1 carat, including the famous Uncle Sam, a whopping 40.23 ct. The park’s diamond-bearing rocks are comprised of hypabyssal olivine lamproite and phlogopite-rich tuffs and breccias, characterized by high Mg# values (atomic ratio of Mg to Fe in an igneous rock) and K2O content (E. Walker, “Petrogenesis of the Prairie Creek, Arkansas, diamondiferous olivine lamproite,” PhD thesis, University of Western Ontario, Ontario, Canada, 1991). The deposit grades between 0.01 and 1.25 carats per 100 tons (D.P. Dunn, “Xenolith mineralogy and geology of the Prairie Creek lamproite province, Arkansas,” PhD thesis, University of Texas, Austin, 2002). In the early twentieth century, when the richest material was mined, there was a brief diamond rush in the area (figure 2). After a string of ownership changes and failed business ventures, visions of a South African–style diamond district never materialized. In 1972 the state of Arkansas purchased the land and opened it to public prospecting. Since then, visitors have found more than 33,000 diamonds (www.arkansasstateparks.com).

Figure 3. A local prospector digging for diamond ore and demonstrating sieving technique. Photos courtesy of Glenn Worthington.
After a couple of days learning about the igneous rocks in the area, it was time to test our luck at treasure hunting. We gathered buckets, shovels, and sieves from park headquarters for a small rental fee and headed out to 15 hectares of routinely plowed “blue ground.” We chose a spot, shoveled soil into buckets, and carried these heavy parcels of dirt to the wash station for sieving (figure 3). The trick is to shake the sieve back and forth just beneath the water in the horizontal plane, then rotate and repeat. This motion should concentrate the heavy minerals in the center and bottom of the sieve. Then, like a master chef, the prospector flips the entire mineral concentrate upside down and examines the heavies that sink to the bottom.

Figure 4. Three of the diamonds the authors collected from Crater of Diamonds State Park (approximately 0.01–0.05 ct). Note the irregular and fragmented morphology and brown to yellow colors. Photos by Roy Bassoo.
In three hours, we found a small collection of diamonds! Granted, they were also very small in size, ranging from 0.01 to 0.05 ct (figure 4). Most prospectors at Crater of Diamonds miss stones this small, but as trained mineralogists we were attentive to small crystals. The diamonds were predominantly colorless, although a couple were yellow to brown. Their dominant morphology was octahedral with uncommon dodecahedrons and macles. Resorption pits and terraced surfaces were pervasive. The diamonds were also fragmented, likely due to the explosive nature of the diatreme crater.

Figure 5. Terraced dissolution surface textures and inclusions of rutile and diopside embedded within the diamond. The diopside inclusions are aligned along a growth band. Photomicrograph by Roy Bassoo.
Treasure in hand, we then turned to the science. Back in our lab, we ground and polished the diamonds into wafers to examine their composition and crystal interiors. Raman spectroscopy determined that inclusions of rutile and diopside were common (figure 5). N contents, measured with Fourier-transform infrared spectroscopy, ranged from trace amounts (type IIa) to 1250 ppm (type IaAB). Cathodoluminescence imagery showed blue to turquoise response colors, typical of diamonds mined from primary deposits worldwide. They also feature fascinating patterns of growth banding and resorption truncations, which indicate a complex mantle crystallization history (figure 6).

Figure 6. Cathodoluminescence image of a polished diamond wafer, showing complex banding and truncations that highlight different diamond growth conditions. Image by Roy Bassoo.
We found Crater of Diamonds to be a thoroughly enjoyable treasure hunting adventure. Our visit gave us hands-on experience with diamond-bearing igneous rocks and challenged us to imagine how diamonds formed beneath the North American craton. We have new appreciation for the back-aching labor required by the artisanal miners worldwide who are the foundation of the gem trade. Scientific understanding and trade awareness were the substance of our visit, highlighted by moments of joyful discovery. We encourage readers to put Crater of Diamonds State Park on their gemology “bucket list” to hunt for their very own American diamond. @chapter:21 @chapter:0 @chapter:21


# Publication Year: 2022
# Title: Spectacular Yellow Sapphire from Sri Lanka
# Abstract: Figure 1. This 160 ct yellow sapphire rough was found in a deposit outside of Ratnapura, Sri Lanka. Photo courtesy of Kreis Jewellery GmbH.
A return to the Tucson shows meant the opportunity to see the latest findings and designs from the Kreis family—stunning yellow sapphire from Sri Lanka. As G&G has reported in previous Tucson reports from 2014, 2015, and 2017, father Stefan buys the rough, mother Sonja designs the jewelry, and Alexander cuts the gems for the family business (Kreis Jewellery GmbH, Niederworresbach, Germany). Locating the sapphire rough in Sri Lanka required a combination of planning and luck, relying on the family’s previously established network while also acting on rumors of possible sources. Two successful trips in 2020 and 2021 yielded five exceptionally large rough stones from five different deposits in the area surrounding Ratnapura, Sri Lanka (figure 1).
Back in Germany, Alexander cut the five rough stones, and Sonja designed an exquisite bracelet (figures 2 and 3) to complete a suite of jewelry for a private collector. (Her previously designed pieces included a pendant, brooch, ring, necklace, and earrings.) The family aimed to create a harmony between the gems and the materials used, concentrating on gold colors that would not overshadow the sapphires. Alexander opted for a traditional cut for the outer shape but faceted the back to allow for more cross-reflection, mimicking this faceting in the diamonds that appear on the side of the bracelet. The creative combination of faceting and design perfectly captures the sunlight, creating magnificent reflections for the admirer. With an impressive total weight of 168.27 carats (containing 50.33, 32.80, 33.70, 23.98, and 27.46 ct sapphires), the bracelet is truly a breathtaking sight.

Figure 2. The yellow sapphires faceted by Alexander Kreis were set in a bracelet designed by Sonia Kreis. Photo courtesy of Kreis Jewellery GmbH.

Figure 3. The stunning finished bracelet features five yellow sapphires from Sri Lanka with a total weight of 168.27 carats. Photo courtesy of Kreis Jewellery GmbH. @chapter:40 @chapter:2 @chapter:40


# Publication Year: 2010
# Title: An Era of Sweeping Change in Diamond and Colored Stone Production Markets
# Abstract: The diamond, colored stone, and pearl businesses have witnessed unprecedented change since the turn of the 21st century. Not only have new markets for gems emerged around the world, but channels of distribution have also changed dramatically as a result of economic forces and political pressures. De Beers abandoned its single-channel seller role, which created —for the first time in over a century—a competitive rough diamond market. Political problems in Madagascar and a ban on gem exports from Myanmar disrupted supply channels for sapphire and ruby. And the proliferation of new sales avenues, through the Internet and TV, has given consumers much more information about gems and forever changed the way they buy them. The use of gems to subsidize bloody conflicts and repressive regimes has moved the trades to become more accountable, as concerns over terrorism and illicit trading have created a new legal environment. At the same time, a new class of consumers who value ethically, socially, and environmentally friendly products are making their demands known in the gemstone business. @chapter:49 @chapter:3 @chapter:49


# Publication Year: 2022
# Title: Unusual Laser Drill Holes in a Laboratory-Grown Diamond
# Abstract: Figure 1. Flux inclusion in a laboratory-grown diamond connected to a laser drill hole. Photomicrograph by Najmeh Anjomani; field of view 3.57 mm.
Diamonds with dark inclusions have been laser drilled to enhance their clarity for more than 60 years. The internal inclusion is drilled from the diamond surface and then acid-boiled to bleach it out. GIA has identified many natural diamonds treated by this technique, but the Carlsbad laboratory recently received for a colored diamond identification and origin report an undisclosed laboratory-grown diamond with unusual laser drill holes.
The diamond was a Fancy yellow cushion modified brilliant weighing 2.02 ct. Gemological and spectroscopic analysis confirmed it was an HPHT-grown synthetic diamond. The diamond was attracted to a small magnet due to the numerous metallic inclusions. No strain was visible under crossed polarizers, and DiamondView imaging showed the typical cuboctahedral HPHT growth pattern.
Clarity was low due to the presence of numerous large flux inclusions, so laser drilling was likely done to enhance the appearance and clarity. One of the laser drill holes connected to a large flux inclusion can be seen in figure 1. A metallic flux inclusion cannot be bleached as some mineral inclusions can and so it must be dissolved out, which could pose additional challenges to improving the clarity. It appears there was an unsuccessful attempt to remove the flux, as the inclusion was still eye visible.

Figure 2. Clusters of unusual laser drill holes in a laboratory-grown diamond. Photomicrographs by Najmeh Anjomani; fields of view 3.57 mm (left) and 2.61 mm (right).
Three clusters of intersecting laser drill tubes resembling corals were observed (figures 2 and 3). We could see numerous roundish openings on the surface filled with dark materials. Raman spectroscopy confirmed they were all non-diamond carbon materials. Here the laser beam was likely reflected off a flux inclusion and refocused to a new point farther than intended, resulting in the unusual branching pattern. Other flux inclusions could have been successfully dissolved by acid because they were smaller than the one in figure 1 or because there were more drilled tubes for the acid to enter. This may have caused the unique crossed tubes inside the stone. Burn marks on the surface next to some of the laser drill holes might have been due to the heat generated by the laser beam (figure 3).

Figure 3. Burn mark on the surface next to laser drill holes. Photomicrograph by Najmeh Anjomani; field of view 2.01 mm.
This diamond was identified as a laboratory-grown diamond. It was issued a laboratory-grown colored diamond report stating, “Laser drill holes are present.” @chapter:36 @chapter:1 @chapter:36


# Publication Year: 1991
# Title: Fall 1991 Gem News International
# Abstract: Diamonds
            Argyle Set to Expand with Mining at Home
            Argyle Also Plans to Expand Cutting in China
            Operations Re-Established at Elizabeth Bay
            Warnings of Large-Scale Theft
            New Soviet Diamond Source
            Additional Diamonds Recovered at Fort a La Corne, Saskatchewan, Canada
            Conference on Synthetic Diamond and Diamond-Like Coatings
            New Diamond Cuts
            Historical Diamond Photographs
Colored Stones
            Colombia Reports Record Emerald Exports
            Large South Sea Pearl
            Myanmar to Authorize Thai Buyers
            Postage Stamp Commemorates Large Burmese Ruby
            Small-Scale Sapphire Mining Continues in Thailand
            Tanzanian Spinel
            Update from Tanzania
            Tanzania Invites Tenders for Mineral Rights
            Large Paraiba Tourmalines
            Tourmaline with Unusual "Color Change."
            Tourmaline/Andalusite: A Pleochroism Caveat
            Purple and "Chrome" Green Vesuvianites from Quebec
            Unusual Red Zoisite
Enhancements
            Faceted Gems Coated with Diamond-Like Carbon
            Montana Sapphire Heat Treatment
            More Experimentation with Blue Diffusion-Treated Sapphires
            Red Stones Also Experimented With
Synthetics and Simulants
            Porous Gilson Synthetic Opal
Instrumentation and New Techniques
            Distinguishing Diffusion Treatment from Surface Coating
            New Setting Method Challenges Diamond Testers
            Jewelry Imaging/Teleconferencing System Introduced
            Tweezer Improvement
Announcements
            Tucson Gem and Mineral Show 1992
            American Craft Assn. Supports Legislation

To view the full section, download the PDF above. @chapter:21 @chapter:1 @chapter:21


# Publication Year: 2006
# Title: Abstracts; Fall 2006
# Abstract: This article, from the Fall 2006 issue of Gems & Gemology, is a compilation of abstracts of important gemology-related articles published outside of Gems & Gemology.

	DATA DEPOSITORY

Table: Magnetic Characteristics of Various Gem Materials Observed by the Direct Method
	Submitted by Sylvia M. Gumpesberger
	Fall, 2005
Table: Degree of Defect Formation in Natural, Synthetic, and Treated Diamond Samples
	Submitted by Joe C.C. Yuan
	Fall, 2005 @chapter:41 @chapter:1 @chapter:41


# Publication Year: 2017
# Title: GSA 2017 Annual Meeting
# Abstract: Figure 1. Presenters, session advocates, and senior executives from GIA at GSA’s annual meeting in Seattle. Photo by Tao Hsu.

The Geological Society of America (GSA) held its annual meeting October 22–25 in Seattle. For the fifth year, GIA hosted technical sessions on gemological research in the 21st century. More than 30 researchers, students, and gem experts from multiple institutions shared their most recent research results (figure 1).

Invited speaker Evan Smith (GIA, New York) presented the diamond inclusion suite study he carried out over the past two years. Following his paper published in Science on type IIa Cullinan-like, large, inclusion-poor, pure, irregular, resorbed (CLIPPIR) diamonds, Dr. Smith investigated in situ mineral phases in more than 20 extremely rare type IIb diamonds selected from GIA’s day-to-day grading operations. The identified inclusions indicated that type IIb diamonds can originate from the lower mantle, at depths beyond 660 km. This surprising result refuted the well-accepted view that almost all superdeep diamonds are small and not of gem quality. Nancy McMillan (New Mexico State University) talked about the diamond provenance study she performed with Catherine McManus (Materialytics, Killeen, Texas). To ease consumer concerns about conflict diamonds, they conducted multivariate analysis of laser-induced breakdown spectroscopy (LIBS) on diamonds from various origins as well as synthetic diamonds. The information provided by LIBS on trace element composition and the electronic structure of atoms in diamonds aided in provenance determination. Through infrared (IR) mapping, Sally Eaton-Magaña (GIA, Carlsbad) and her colleague Troy Ardon documented the spatial changes of the optical defect center B0 (uncompensated boron) in two type IIb diamond samples: One specimen was irradiated along an edge and then annealed, while the other was only annealed. The irradiated diamond showed an obvious gradient in B0 across the specimen itself and larger gradient changes during annealing compared to the other sample. These were caused by changes in compensating defects, which were then plotted by photoluminescence (PL) mapping.

The following three presenters from the University of Alberta shared their intriguing diamond formation research. Mandy Krebs offered trace element data of fluids trapped in gem-quality diamonds and compared them to those in fibrous diamonds that have been extensively studied. The results showed clear similarities in trace element patterns in both categories, which indicates that fibrous diamonds and gem diamonds may share a common origin. Rebecca Stone reported on diamond growth in saline fluid. She and her colleagues carefully documented diamond growth features under different salinities using a mixed KCl-NaCl brine system within the diamond stability field. Their series of experiments showed that Na-rich brine is a better medium for diamond growth than K-rich or Na+K mixed brines. Robert Luth discussed the partial melting mechanism facilitating diamond formation. He noted that the amount of diamond formed during this process depends on the lithology being melted and the composition of the fluid. The origin of the C-bearing fluid was also explored.

Following the diamond research presentations, invited speaker Darrell Henry (Louisiana State University) started the colored stone session with a talk on gem tourmaline. He pointed out that tourmaline is a very sensitive mineral that can incorporate and retain chemical and textural fingerprints from its environment. Paraíba, Paraíba-like, liddicoatite, and “chrome” tourmaline were used to illustrate this mineral’s incredible scientific value. Aaron Palke (GIA, Carlsbad) discussed his recent findings on demantoid garnet’s coloration mechanism. The existing theory attributes the brown coloration of this gem to intervalence charge transfer between Fe2+ and Ti4+ or Fe3+. Dr. Palke challenged this interpretation based on recent spectroscopic results showing insufficient Fe2+ in demantoid to justify this mechanism. Philippe Belley (University of British Columbia) addressed the challenges of modeling spinel deposits. His potential solutions are based on detailed petrographic and geochemical studies on 14 samples from exceptionally well-exposed in situ spinel occurrences on Baffin Island in Nunavut, Canada. Donald Lake (University of British Columbia) compared two beryl occurrences in northern Canada with Colombian emerald deposits. He pointed out that in terms of formation environment, these potential emerald deposits are the first “Colombian-type” sources outside Colombia. Rachelle Turnier (University of Wisconsin–Madison) presented her study on oxygen isotope fractionation factors in corundum. Oxygen isotope ratios are important to understanding corundum genesis and origin determination. This study empirically calibrated the calcite-corundum oxygen isotope fractionation factor from the metamorphosed karst-bauxite deposits at Naxos, Greece. GIA’s Jennifer Stone-Sundberg closed this portion of the session with a presentation on matrix-matched corundum standards development. She explained the importance of these newly developed standards in accurately determining trace element concentration and elaborated on the advantages of these standards over other commonly used products.

Figure 2. The GSA annual meeting’s gemological research poster session featured 18 presenters from all over the world. Photo by Cathy Jonathan.
This year’s poster session attracted 18 presenters, triple the number from last year (figure 2). Daniel Howell (University of Padua) presented new applications of DiaMap software in automated and semi-automated mapping of single substitutional defects (N and B) and micro-inclusion-bearing diamonds. Paul Johnson (GIA, New York) reported the first observation of nickel as the cause of the green color of an HPHT synthetic diamond. Nickel is commonly used in the metal flux that produces HPHT synthetic diamond, but it rarely contributes to diamond coloration. Tyler Sundell (Missouri State University) evaluated the viability of in situ 13C measurement in diamonds using time-of-flight secondary ion mass spectrometry (ToF-SIMS). Tingting Gu (GIA, New York) shared her study on micro- and nano-inclusions containing both N and Fe in type IaB diamonds. Kyaw Soe Moe (GIA, New York) presented the identification features of irradiated and annealed pink diamonds using IR spectroscopy and DiamondView imaging. Elizabeth Levy (Louisiana State University) explained how to directly measure Fe2+ and Fe3+ concentration in tourmaline crystals using synchrotron-based X-ray absorption near-edge spectroscopy (XANES). Cole Mount (New Mexico State University) found that using multivariate analysis of LIBS spectra of tourmaline can remove the negative influence of chemical zoning on host lithology determination. Ulrika D’Haenens-Johansson (GIA, New York) gave her insights on the 812 ct Constellation and two other large rough diamonds. FTIR and morphology observations indicate that the three could possibly be pieces from the same rough. Christopher M. Breeding (GIA, Carlsbad) described the first ever co-occurrence of magnesite, olivine, graphite, and silicon-vacancy defects in natural diamonds and explored the unusual conditions under which these diamonds formed. Karen Smit (GIA, New York) discussed the formation of peridotitic diamonds through isochemical cooling and eclogitic diamonds through redox buffering. George Harlow (American Museum of Natural History, New York) and Rachelle Turnier discovered that syenite-hosted sapphires from six different sources show a wide range of δ18O values, which indicates scavenging of sapphire from multiple reservoirs. Troy Ardon (GIA, Carlsbad) used IR mapping, cathodoluminescence (CL) imaging, and hyperspectral mapping to correlate various optical and infrared point defects in diamonds with strong brown coloration. Susanne Schmidt (University of Geneva) outlined U-Pb geochronology work done on zircon inclusions in Sri Lankan sapphires. This study was performed by her former graduate student Emilie Elmaleh. Ziyin Sun (GIA, Carlsbad) investigated the role of chromophore vanadium in coloration of pyrope-spessartine garnet, using samples without a color-change phenomenon. Eric Brinza (University of Wisconsin–Eau Claire) described an IR spectroscopic study on hydrothermal quartz crystal. Different hydroxyl species concentrations vary both vertically and horizontally through the crystal. Kyle Tollefson, also of the University of Wisconsin–Eau Claire, presented IR and visible spectroscopic study on coloration of watermelon tourmaline. The results showed that the chromophore was incorporated during crystal growth and could reflect changes in the growth environment. Dona Dirlam and her coauthors from GIA’s Richard T. Liddicoat Gemological Library and Information Center (Carlsbad, California) chronicled the legendary John Sinkankas, whose collection of books and other publications was acquired by GIA in 1988 to form the basis of its world-renowned gemological library. @chapter:44 @chapter:1 @chapter:44


# Publication Year: 2014
# Title: Books: Gem Identification Made Easy
# Abstract: By Antoinette Matlins and A.C. Bonnano, 378 pp., hardcover, illus., publ. by GemStone Press, Woodstock, VT, 2013. US$38.99.

              Originally published in 1989, Gem Identification Made Easy caters to a very broad audience of gem enthusiasts. It serves to inform and educate inexperienced gemologists, a good reference tool for seasoned veterans. Overall, this book contains a wealth of valuable information on simple, practical testing methods, written in a concise, easy-to-understand style.

Many tips and tricks for detecting treatments and how to differentiate between natural and synthetic materials are covered. Of particular interest in this latest edition is a section dedicated to identifying glass-filled rubies, which have plagued the market in the last few years. This chapter will clearly help even novice gem buyers and sellers avoid a costly mistake regarding this material.

However, this book lacks in the same measure of detail regarding diffusion treatment of corundum, which is at least as problematic in the gem trade as glass-filled rubies. The other area where it falls a bit short is image quality. Although color plates are included in this version, the images are small and in some cases very poor illustrations of their intended subjects. Most of the instructional images throughout the text are otherwise adequate.

Overall, this is a welcome addition to any gemological library, especially for the gemologist who must rely on portable instruments. If you’re in search of a “how-to” book full of vibrant images, this is not the one for you. If you are a gemologist at any level in need of a practical guide to gem testing or a reference guide, then you will be quite satisfied with this book. @chapter:16 @chapter:0 @chapter:16


# Publication Year: 1998
# Title: Summer 1998 G&G Book Reviews
# Abstract: “The Pearl Book: The Definitive Buying Guide—How to Select, Buy, Care for & Enjoy Pearls”
By Antoinette L. Matlins, 198 pp., illus., publ. by GemStone Press, Woodstock, VT, 1996. US$19.95

“Gemstones of Brazil: Geology and Occurrences”
By Patrick J. V. Delaney, 125 pp., illus., publ. by Revista Escola de Minas, Ouro Preto, Brazil, 1996. US$23.80

“Encyclopedia of Mineral Names”
By William H. Blackburn and William H. Dennen, illus., edited by Robert F. Martin, 360 pp., illus., publ. by the Mineralogical Association of Canada, Ottawa, Ontario, 1997. US$40.00

“Proceedings of the Sixth International Kimberlite Conference”
Edited by N. V. Sobolev and R. H. Mitchell, 619 pp. in two volumes, illus., publ. by Allerton Press, New York, 1997. US$95.00 (individuals), US$225.00 (institutions)

To view the full section, download the PDF above. @chapter:30 @chapter:0 @chapter:30


# Publication Year: 1999
# Title: Some Diagnostic Features of Russian Hydrothermal Synthetic Rubies and Sapphires
# Abstract: Most Russian hydrothermal synthetic rubies and pink, orange, green, blue, and violet sapphires—colored by chromium and/or nickel—reveal diagnostic zigzag or mosaic-like growth structures associated with color zoning. When the samples are properly oriented, these internal patterns are easily recognized using a standard gemological microscope in conjunction with immersion or fiber-optic illumination. Pleochroism is also useful to separate chromium-free blue-to-green synthetic sapphires from their natural counterparts. Samples colored by a combination of chromium, nickel, and iron are also described. @chapter:19 @chapter:1 @chapter:19


# Publication Year: 2017
# Title: Tourmaline and Sapphire from Nigeria
# Abstract: Figure 1. High-quality rubellite rough is highly sought after in the Asian market. Photo by Eric Welch/GIA, courtesy of Zoe Michelou.

	Zoe Michelou, marketing manager for a Nigerian mining company, gave an update in Tucson on the production of gemstones, particularly tourmaline. She primarily handles sales and marketing of rubellite from Oyo State, where there are around 350 pits. There are usually 10 to 15 miners per pit. The miners descend 10 to 20 meters by ladder to the bottom of a pit, and then the pegmatites are blasted and tunneled before extraction. Some tunnels are linked when production overlaps, improving air circulation. Pits can be very close together, although some larger open-pit operations have excavators in the pits and carts to remove the ore. Rubellite is concentrated in pockets within the pegmatites. There are plans to increase mechanization and redesign tunnel orientation and air circulation, thus increasing blasting cycles and production, and new pockets are being discovered.

	Miners are provided with food and tools, as well as by profit sharing based on the value of the production. There are plans to include a salary, health care, and a bonus on production. Sometimes miners can recover one ton of rubellite from a large pocket. Large single crystals can easily reach 18 kg or more. The rubellite is kept in a safe and then transported to the city of Ibadan for grading every two to three weeks, depending on production. Currently there are only three to four quality categories. Most of the material is now shipped to Bangkok for final grading and sale. A new facility is planned to perform the final grading in Nigeria, with training of locals to create parcels for international clientele. Many of the rubellite crystals sent to Bangkok weigh 1 kg or more.

	There are also alluvial deposits where rubellite pebbles can be recovered without moving too much earth. In Kwara State there is a significant production of indicolite and green tourmaline, including some pink and bicolor. Most of the mining is still near the surface, with a few deeper pits. The first production of indicolite tourmaline sent to Bangkok had crystals of 2–34 grams ranging from commercial to very high quality.

	Currently, the Nigerian company is focused on selling rough rubellite (figure 1) through the Bangkok office and trade shows to the international market, especially in East Asia. The clients are mainly rough dealers and manufacturers from China, Hong Kong, and Thailand. This year, the company will start a training program for grading at the mining site in Nigeria. In the future, rough will be sorted and graded prior to shipment to Bangkok.

	The parent company that Michelou represents has acquired 1,000 square kilometers for sapphire exploration, prospecting, and mining licenses in the Mambilla Plateau area of Taraba State. Nigeria has produced large quantities of fine-quality basalt-related sapphires. Extraction should start by late spring, with sales expected by the end of 2017 or beginning of 2018. They will only sell rough sapphires in selected markets. The initial washing plant will be able to handle 50 tons of ore per hour. Good-quality material weighing 3 to 5 grams is already being recovered. Security will be tight, and dealers from the Cameroon side of the border currently buying from unlicensed miners have already been restricted from the commercial mining area. Transparent supply from the mine to rough markets is an important part of the marketing strategy. The company will soon implement a detailed grading system for rough sapphires.

	The company primarily sells rough but also sells some cut stones to manufacturing jewelers worldwide. Michelou sees an increase in manufacturing jewelers buying rough, including tourmaline and sapphire, and having it cut instead of just purchasing finished stones. By doing so, they can guarantee traceability of the stones all the way to the customer.

Figure 2. A sampling of Nigerian indicolites after fashioning. Photo by Eric Welch/GIA, courtesy of Zoe Michelou. @chapter:23 @chapter:0 @chapter:23


# Publication Year: -
# Title: Spring 2019 Auctions: Premium Prices for Historic Pieces
# Abstract: A circa 1935 Art Deco emerald and diamond creation, presumably made by Van Cleef & Arpels for American socialite and collector Hélène Beaumont. Courtesy of Sotheby’s

While the major auction houses are still making news with their rare gemstone offerings, the news about recent sales is focused more on history than record prices.
This year’s auctions have seen fewer lots, fewer very large diamonds and an easing of prices from the record levels seen a few years ago. But auction executives are quick to point out that the market for high quality gems and jewels is still robust – for pieces with a historic past.
“Our April New York auction represents the market, right now,” said Rahul Kadakia, Christie’s International Head of Jewellery. The April 16 sale did not have any top fancy colored diamonds over 5 carats or D flawless diamonds larger than 25 carats, as had been the case in recent years. In addition, a high percentage of lots came from estates, not dealers.
Several 15 ct-plus diamonds achieved per carat prices of more than $100,000 at the sale, which he acknowledged was down from the peaks of $150,000 to $180,000 in mid-decade.
“That was a spike in the market,” he explained. “But if you look at the long run, prices have risen substantially for such stones over the years.”
Sotheby’s May 14 Geneva sale saw one large D fl (36.57 ct) diamond sell for about $5 million ($136,000 per carat), but most of the action was for signed period jewels, such as The Beaumont Necklace, a circa 1935 Art Deco emerald and diamond creation, presumably made by Van Cleef & Arpels for collector Hélène Beaumont, that sold for $3.6 million, about 20% above its estimate.
Tailoring Auction Items to Market Demand
When the market weakens for major gemstones, the auction houses have to become more careful about curating their sales – smaller high-quality stones, more classic “signed” period jewels – and concentrate more on estate pieces. Prices are usually less aggressive than those from dealers, Kadakia said.
Dealers who sell at auction said they need high prices to recoup the auction seller premiums of 12% to 15% on sales. (Note that auctions also charge buyers a similar rate. Thus, if a gemstone has a hammer price of $100,000, the buyer will likely pay $115,000 and the seller will receive about $85,000.)
Sotheby’s and Christie’s have reduced the number of lots in their major jewelry sales by 25% to 35% in the past two years because, even though these houses almost never own pieces they sell, they go all out to avoid “buy-ins” – lots that fail to find bidders.
“The auctions’ publicity power works against them if this happens,” explained one major dealer of fancy colored diamonds. “If pieces don’t sell, everybody knows it right away and they start to worry about the market.”

The Jonker V, a 25.27 ct GIA-graded D VS1 diamond, was cut in 1934 from the famed 726 ct Jonker Diamond, found in South Africa. © Christie, Manson & Woods LTD (2019)
Kadakia said prices for major colored stones seem less affected by the slowdown; top sales lots are usually fancy colored diamonds. The top lot of Christie’s May 15 Geneva sale was a 22.86 ct cushion shaped Burmese ruby that sold for $7.2 million, more than twice its pre-sale estimate, and a natural pearl sautoir (a long necklace that can suspend a pendant or tassel) that brought $5.8 million from a dealer.
The May 15 sale did feature two significant diamonds:

An 118 ct GIA-graded Fancy yellow diamond purchased for $7.1 million (twice the estimate) by Siba Corp., a New York-based dealer of major gemstones, in honor of its founder Sam Abram who had passed away shortly before the sale
The Jonker V, a 25.27 ct GIA-graded D VS1 diamond cut in 1934 from the famed 726 ct Jonker Diamond, found in South Africa, which achieved its estimate of $3 million

One-of-a-Kind Pieces and Prices
But even when prices in general are softening, truly one-of-a-kind pieces will always command top-dollar because buyers know they will not likely see them again.
“A perfect case in point was the Wittelsbach blue diamond,” Kadakia said. “We sold that for a record $23.4 million in 2009 when the financial markets had crashed.”

The Catherine emerald, mined in Colombia over 250 years ago, sold for $4.3, nearly $1 million above its high estimate. The emerald, originally a 107 ct square cut, was acquired by Catherine the Great, the Russian monarch, around 1790 and passed through Russian royalty until 1920. The gem was recut in 1954 to remove inclusions.  Photo Russell Shor/GIA
The most publicized lot of Christie’s May 15 auction was surely one-of-a-kind: The Imperial Emerald of Grand Duchess Vladimir of Russia, which originally belonged to empress Catherine the Great.
The emerald’s rich history started when it was acquired as a 107.67 ct square cut by Catherine the Great toward the end of the 18th century. It passed through Russian royalty after her death until Cartier purchased it in 1927. Cartier had the emerald recut into a pear shape of 75.63 cts to eliminate most of the fissures and inclusions and then sold it to John D. Rockefeller Jr. in 1954.
Valuing the gem was difficult because of its provenance, Kadakia said.
“We met with the trade, as we often do, and they asked us to list it without adding its history to the price.”
Christie’s experts listed the pre-sale estimate of $2.3 million to $3.5 million in the catalog.
“If we’d gotten that, then it we could say we achieved the value of the emerald itself. Anything higher would be the add-on for its history,” Kakadia noted.
When the bidding ended, an anonymous private buyer paid $4.3 million for the emerald, adding about $1 million for the history.

The 19 ct Fancy Light pink Le Grand Mazarin diamond was presented to French King Louis XIV in 1661 by Cardinal Mazarin, passed through a succession of French monarchs and, later, emperor Napoleon Bonaparte. © Christie, Manson & Woods LTD (2017)
Two years ago, Christie’s added $1 million to the $4 million pre-sale estimate of the 19 ct Fancy Light pink Le Grand Mazarin diamond presented to French King Louis XIV in 1661 by Cardinal Mazarin. It was then passed through a succession of French monarchs and, later, emperor Napoleon Bonaparte.
In Kadakia’s words at the time “it was the diamond with the most prestigious and historic provenance still in private hands.” The diamond, which was offered at a November 2017 sale, had been sold in 1887 at the auction of the French crown jewels and was sold through private collections until resurfacing for this auction.
“In the end, the stone sold for almost $15 million – an $11 million premium because of its history,” he said. @chapter:42 @chapter:3 @chapter:42


# Publication Year: -
# Title: Jadeite Whisperer: Shanghai Jewelry Designer Kaka Zhang
# Abstract: Jewelry designer Kaka Zhang’s unique designs are inspired by nature and her culture, and by memories of things she has seen in the past. Photo courtesy of Kaka Zhang

                      It’s rare to meet someone whose interests as well as talents encompass art, science, and business, but such was the case when we met successful jewelry designer Kaka Zhang in Shanghai, China. When she was three, her father—who wanted her to be an artist—taught her painting. In high school she acquired an interest in, and studied, science and technology. This led her to study gemology at the East China University of Science and Technology under the guidance of Prof. Shouguo Guo.

	Jadeite Buddha Goddess: Guanyin

	Gemology, Art, Science, and Business
Her gemology studies led Miss Zhang to a career that was the perfect combination of science, art, and business. Prof. Guo guided her to jewelry design and e-commerce based on her artistic talents and her interest in the future potential of the internet. Miss Zhang had also worked for an internet company and was convinced of the tremendous business potential of e-commerce.

	Miss Zhang is a rare combination: A passionate, inspired artist and an astute business
	woman. Photo courtesy of Kaka Zhang
Although Miss Zhang was not a jewelry design major, she was able to develop her artistic talents and expand on her painting background with daily practice. She came to the realization that jewelry design requires a combination of art, material selection, and manufacturing knowledge.

Most of Miss Zhang’s design inspirations come from nature and are meant to display nature’s beauty. When she was young, she spent time with her grandfather in the family garden. Those days led to her love of incorporating naturalistic themes into her designs. Also, she points out that nature, flowers, and trees are major themes of traditional Chinese paintings.

	A Tradition of Nature Themes

	Jadeite and Her Jewelry
Jadeite is the main gemstone used by Miss Zhang in her jewelry designs. She explains that it comes in a wealth of colors and patterns, and its luster and texture suit the tastes of the Chinese. In the interviews, she expresses her feelings about the unique bond between jadeite and the Chinese culture. She states that jadeite is varied and graceful and, like Buddhism and Chinese medicine, has deep meaning for the Chinese people that cannot be easily explained. She feels that jadeite jewelry design should reflect China’s history and cultural significance.

	Traditional Buddha Bead Chain

While Miss Zhang loves vivid, transparent jadeite, she also loves incorporating blue hues, both evenly colored and with mottled coloring that resembles floating clouds or flowing water. She says that the blue hues have a more conservative look preferred by many in her age group.

	Miss Zhang likes to use jadeite with a bluish color component. Photo courtesy of Kaka Zhang

	Creating the Design
When it comes to actually creating a design, Miss Zhang holds the piece of jadeite in her hands to feel its shape and quality. She considers what she can add to the piece and what impression it brings to mind. Miss Zhang says that every piece of jadeite is unique and always reminds her of something she has seen in the past.

She gets a great deal of inspiration directly from a piece of jadeite. It might remind her of a landscape. If a piece reminds her of a goldfish, she might design a jewelry piece to resemble a fish jumping out of the water. She often purchases jadeite carved into different shapes like leaves, flowers, and calabash—a gourd that symbolizes wealth and good luck to the Chinese.

	Cultural Themes

	Miss Zhang uses a wide range of jadeite qualities, including fine green material, in her jewelry creations. Photo courtesy of Kaka Zhang

	The Market for Her Pieces
Miss Zhang’s jewelry pieces fall into high end, moderate, and commercial price ranges. The high-end pieces are usually sold to her older clientele so she incorporates traditional designs into them. She designs pieces set with high-quality jadeite in a more natural state, following the jadeite’s essence and adding a few design elements as decoration. For lower-priced jewelry, her designs are more imaginative and she adds more elements. Most of the customers for moderate- to lower-priced pieces are younger and more open to imaginative designs with a variety of design elements.

	High-quality Jadeite Water Drop

Miss Zhang told us that traditional designs are safer and that a greater use of imagination is riskier and comes with some expectation of failure. But she likes being imaginative and trying different designs. When it comes to design, she prefers to follow her heart and not just the commercial market. This explains why she has become recognized for her work.

Many Chinese consumers place a lot of importance on jewelry’s intrinsic value, so the price range of the jewelry must reflect both the value of the materials and the design and workmanship. She says that although Western designers can demand high prices based on design and branding, Chinese designers must base price also on the value of the components. Her clients are often not as traditional as many Chinese consumers and will focus more on the design aspects of the piece and how it affects their feelings when buying.

Miss Zhang sees a direct correlation between her sales and the growth of the Chinese economy and the rise of China’s importance as an economic power. When discussing jadeite sales, she says the Chinese have an old saying: “Buy gold when society is not stable and buy jade when it is prosperous.” She says that China’s economic boom is the reason the country’s jade market has been so strong.

	Her Business and Customers
Women are the primary target market for her designs and materials, and make up 99 percent of her customer base. She does business primarily on the internet and her customers are mostly in their 20s to 40s. Even within that group, however, there are differences in taste.

While older customers have more discretionary income to buy jewelry, they do not buy from the internet as much as those in her customers’ age group. Because of her older customers’ higher spending capacity, they select jewelry pieces with higher-value jadeite. Higher jadeite quality levels are more accepted in their social circles and at the events they attend.

Customers in their 20s do not have as much of a budget for jewelry purchases. They often buy transparent, near-colorless jadeite that is extremely popular with their age group but not as accepted by customers in their 40s. Although the price point of this jadeite quality, called ice jade, is lower and better suited for customers in their 20s, the price has been going up due to its popularity and demand.

Ninety percent of Miss Zhang’s business is on the internet, and she has a loyal and enthusiastic customer following. She sells 80 percent of her pieces immediately after they’re posted on her website. She addresses concerns about buying expensive pieces online and builds trust by inviting customers to her studio and holding events to show special high-value pieces.

	Jadeite Bangle Bracelet

Customers often bring friends, so her customer base continues to grow. Ninety percent of her clients are in mainland China, with 10 percent from Taiwan, Hong Kong, and overseas.

In the interview, Miss Zhang describes her Small Office Home Office (SOHO) life to us. Her design studio and internet business are run from her home in Shanghai. Her jewelry is manufactured by a factory in Shenzhen. She visited numerous factories before selecting the master jewelers she felt comfortable communicating her designs to. She has a great relationship with them, and the jewelers skillfully translate her designs into finished jewelry. She describes their relationship this way: “I play the role of their eyes and they are my hands.”

One of the interesting aspects of her career is that over the years she has met many clients who share her passion and ideas. They have become more than customers—there are many that she considers friends. Her conversations with them are a great treasure to her. Many of them have supported her since the beginning of her career. In fact, many customers send their daughters to her to learn about jewelry design. Miss Zhang is happy to see their interest in becoming the future jewelry designers of China.

	Her Business Style
Miss Zhang firmly believes in educating her customers about jewelry design and materials. She has written articles on the subject and also explains it to customers in person. She says, “I think selling is not just pushing customers and telling them how low-priced the pieces are. You should be able to teach your customers and enrich their knowledge about gemstones. Then they will trust you and accept your brand. I am more like a consultant than a pure salesperson.” She also posts jadeite pieces for her customers and listens to their design ideas while educating them about design and manufacturing, allowing for the creation of customized pieces.

	Combining Materials

Her dream is to run a private jewelry club instead of a retail store. Miss Zhang feels that retail stores are too commercialized and formal for her. She prefers to create an easy and relaxed environment for her customers and treat them more as friends. @chapter:45 @chapter:2 @chapter:45


# Publication Year: 1986
# Title: Spring 1986 Gem News International
# Abstract: Diamonds
            India: New Deposits Discovered
            Japan: World’s Largest Synthetic Industrial Diamond
            South Africa: Diamond Inclusions in Pyrope
            Sri Lanka: Geological Exploration Planned
Colored Stones
            Fade Testing Yellow Sapphire
            Pala in Sri Lanka
            Unusual Sri Lankan Sapphires
Synthetics
            “Watermelon” Beryl
Announcements
            Lizzadro Museum of Lapidary Art
            World Diamond Conference in Tel Aviv

To view the full section, download the PDF above. @chapter:21 @chapter:0 @chapter:21


# Publication Year: 2022
# Title: Quarterly Crystal: Hillocks on Beryl
# Abstract: Figure 1. Measuring 22.28 mm in length and weighing 31.06 ct, the outer pinacoidal surface on the termination of this Pakistani aquamarine crystal is decorated with numerous hexagonal growth hillocks. Photo by Nathan Renfro.
Whenever we study natural uncut gem minerals, we carefully examine all outer surfaces for any photogenic etch figures or growth hillocks that might yield interesting and educational photographs. For this issue’s Quarterly Crystal, we recently had the opportunity to study a very well-formed, gem-quality aquamarine crystal supplied by Ali Shad of Shad Fine Minerals in Gilgit-Baltistan, Pakistan. The aquamarine, pictured in figure 1, was reportedly from the Qandahar mine, located in the Braldu Valley, Shigar District, Gilgit-Baltistan, Pakistan.
At 31.06 ct with corresponding measurements of 22.28 × 14.50 × 11.24 mm, this aquamarine did not show etch figures on any of its crystal faces, proving that the beryl had not gone through post-growth dissolution. However, examination showed that the pinacoid was completely covered with small hexagonal growth hillocks (figure 2) of the type discussed by John Sinkankas in Emerald and Other Beryls (1981) and illustrated on page 273. The hillocks on the terminal pinacoid, which were all generally of the same small size, blanketed the termination completely. Under high magnification, the hexagonal hillocks appeared very complex in form (figure 3). Their sharp, pristine, geometric habit once again illustrated that post-growth dissolution of this crystal had not taken place.

Figure 2. The generally uniform size of the numerous growth hillocks on the terminal pinacoid of the aquamarine is clearly shown in this shadowed reflected light image. The bright colors result from light interacting with thin-film separations in the body of the aquamarine. Photomicrograph by Nathan Renfro; field of view 7.97 mm.

Figure 3. The complexity of some of the hexagonal growth hillocks on the pinacoid of the aquamarine is shown in closer detail in this differential interference contrast image. Photomicrograph by Nathan Renfro; field of view 2.32 mm. @chapter:13 @chapter:0 @chapter:13


# Publication Year: 2024
# Title: The price of pearl jewelry in Denmark has increased by more than 500 percent.
# Abstract: Due to the COVID-19 pandemic situation, pearl farms have halted production, coinciding with a rapid increase in the popularity of pearls in the fashion industry. This has led to a significant rise in prices for high-quality cultured pearls over the past few months.

Importing and jewelry company Birgitte Munch provided information to the Danish business newspaper Børsen, stating that the prices of cultured pearls in the global market have surged. Companies now need to pay over five times more to purchase these products for manufacturing. This observation is echoed by jewelry auction company Bruun Rasmussen Kunstauktioner.

Torben Skov Pearls, one of Denmark's largest pearl importers, with a stock of over 100,000 cultured pearls, revealed that they exported a large quantity of pearls to China for the first time since 2543 B.E. This trend has been observed both in the general fashion industry and on red carpets.

Additionally, Torben Skov Pearls, the pearl jewelry importer, mentioned that the popularity of pearls in the pearl and jewelry industry has rapidly increased over the past decade, especially since 2561 B.E. Danish female consumers prefer large baroque freshwater pearls due to their affordability, using them for earrings and pendants.

Moreover, in recent years, pearls have become a popular item for men as well. Since 2562 B.E., celebrities and famous male personalities, including British singer Harry Styles, actor Jason Momoa, Danish designer Søren Le Schmidt, singer Christoffer, and TV presenter Abdel Aziz Mahmoud, have been wearing pearl jewelry, particularly white cultured pearl necklaces.

This popularity in pearls is part of the understated luxury trend, complementing vintage watches from the 1950s-1960s and Hermès bags, reflecting simplicity, classic elegance, and luxury for the wearer. @chapter:45 @chapter:3 @chapter:45


# Publication Year: 2021
# Title: Adapting to the Changes with Paula Crevoshay
# Abstract: Figure 1. This award-winning pendant featuring a 5.30 ct heated orange sapphire from Montana depicts a blooming brown-eyed Susan. Wildflowers are one of Paula Crevoshay’s favorite themes. Courtesy of Paula Crevoshay.

With the cancellation of the 2021 Tucson AGTA show, this author’s annual meeting with jewelry designer Paula Crevoshay went virtual. The conversation started with her 2020 AGTA Spectrum Award–winning piece, followed by how her business adapted to the new norm under the circumstances brought by the pandemic.
Ms. Crevoshay’s “Brown-Eyed Susan” won the Gem DIVA Award for classical wear (figure 1). This bespoke 18K yellow gold pendant features a 5.30 ct orange Montana sapphire from the Rock Creek deposit, operated by Potentate Mining. Although this stone is heated, the color saturation and size still make it a significant sapphire from this location, according to the mine owner. The center stone is accented with yellow and orange sapphires (8.69 carats total) in addition to black and cognac diamonds (1.98 carats total).
While Ms. Crevoshay has always blended the nature of the stones with her art, she also tells stories through her jewelry creations. This piece is no exception. It continues the story from her first-ever flower themed piece, inspired by the bitterroot wildflower, which thrives on the hillsides of the Rock Creek sapphire mine. By early June, the slopes are covered by bitterroot and brown-eyed Susans. Upon seeing this orange sapphire, she immediately thought to place it at the center of a brown-eyed Susan pendant. Creating these beautiful floral jewelry pieces is never easy because of the time it takes to find so many stones in specific colors. This is also why she has never reproduced any of her jewelry, unless as a replacement for a lost piece.
As a business owner, Ms. Crevoshay also felt the impact of the pandemic. With careful planning and quick adaptation, she was able to keep her employees safe so that they could continue to work. In fact, 2020 was a good year financially for her company due to the relationships built with the stone supply chain over the past several decades and the customer base she has carefully maintained. To help manufacturers downstream survive, she also intentionally diverted her work to different jewelry-making studios, most of them located in Asia.
Being able to talk face-to-face with customers and provide fashion suggestions even beyond jewelry wear is an asset; connecting with them virtually during the pandemic is also critical. Ms. Crevoshay hosts regular online gatherings with her clients, which have been quite successful in keeping people in the loop. During the 2020 holiday season, she created a digital flipbook for customers to explore at their convenience (see figure 2).

Figure 2. Paula Crevoshay’s digital flipbook for the 2020 holiday season featured more than 50 jewelry creations. Courtesy of Paula Crevoshay.
Ms. Crevoshay advises that staying connected at all times and adapting to unexpected circumstances are key for both industry veterans and newcomers. @chapter:25 @chapter:2 @chapter:25


# Publication Year: 2018
# Title: D-Color Natural IIa Diamond with Walstromite Inclusion
# Abstract: Figure 1. A CaSiO3-walstromite inclusion (100 μm) in a 3.0 ct diamond with fan-shaped black fractures. Graphite (less than 10 μm) was identified in the black fracture. Photomicrograph by Ying Ma.
Nondestructive testing methods such as Raman, photoluminescence (PL), and infrared spectroscopy have been widely applied to identify diamond and its inclusions. The NV0/− (nitrogen-vacancy) and V0 (vacancy) centers are used as a probe to confirm whether the color of a type IIa diamond is natural or caused by high-pressure, high temperature (HPHT) treatment or irradiation (Fall 2016 Lab Notes, pp. 299–301; D. Fisher et al., “The vacancy as a probe of the strain in type IIa diamonds,” Diamond and Related Materials, Vol. 15, No. 10, 2006, pp. 1636–1642).
Recently, the National Gemstone Testing Center (NGTC) laboratory in Shenzhen received a 3.0 ct diamond for identification. The stone was a standard round brilliant cut with D color, SI2 clarity, and a diameter of 9.2 mm. When exposed to DiamondView imaging, the diamond exhibited medium blue fluorescence. It was identified as type IIa because no nitrogen- or boron-related absorptions were detected in the 800–1400 cm–1 range and at 2802 cm–1. Nitrogen-vacancy centers NV0 (575 nm) and NV– (637 nm) were not detected, either.

Figure 2. In these Raman spectra, the blue line represents a reference spectrum for CaSiO3-walstromite (Smith et al., 2016, supplementary materials; 500–1100 cm–1). The red trace is from CaSiO3-walstromite in the 3.0 ct diamond (500–1100 cm–1) in the inset photo. The black line shows that the fissure is filled with black graphite; the peak at 1576 cm–1 is the G band of graphite, and the D peaks belong to diamond.
Magnification revealed some mineral inclusions and fan-shaped fractures (figure 1). Part of the fissure was filled with black material. We identified the inclusion in figure 1 as CaSiO3-walstromite and confirmed that the black fracture contained graphite using a Renishaw inVia micro-Raman confocal microscope equipped with a green solid laser (532 nm) focused through a 50× short-working-distance objective (figure 2). As the most abundant Ca-bearing mineral inclusion found in superdeep diamonds, CaSiO3-walstromite is believed to derive from CaSiO3-perovskite. Perovskite-structure minerals are predominant in the earth’s lower mantle more than 600 km below the surface. The presence of CaSiO3-walstromite and Ca-silicate inclusions is a strong indication of superdeep origin (C. Anzolini et al., “Depth of formation of superdeep diamonds: Raman barometry of CaSiO3-walstromite inclusions,” American Mineralogist, Vol. 103, No. 1, 2018, pp. 69–74).

Figure 3. In this DiamondView image of the 3.0 ct diamond, the black arrow indicates the site of dislocation networks. Image by Ying Ma.
The 3.0 ct diamond was similar to CLIPPIR (Cullinan-like, Large, Inclusion-Poor, Pure, Irregular, and Resorbed) diamonds (E.M. Smith et al., “Large gem diamonds from metallic liquid in Earth’s deep mantle,” Science, Vol. 354, No. 6318, pp. 1403–1405). Many CLIPPIR diamonds are of top color grades and type IIa, originating from a depth between 360 and 750 km. Dislocation networks, a relatively common feature in type IIa diamonds, were also found (figure 3). Dislocation networks in diamond are interpreted to be equivalent to the polygonized structure of dislocations in other minerals that have been deformed and subsequently annealed (H. Kanda et al., “Change in cathodoluminescence spectra and images of type II high-pressure synthetic diamond produced with high pressure and temperature treatment,” Diamond and Related Materials, Vol. 14, No. 11-12, 2005, pp. 1928–1931; K. De Corte et al., “Overview of dislocation networks in natural type IIa diamonds,” Fall 2006 G&G, pp. 122–123). High-temperature experimental treatment of synthetic type II diamond can also reproduce dislocation structures (H. Kanda et al., 2005; D. Fisher et al., “Brown colour in natural diamond and interaction between the brown related and other colour-inducing defects,” Journal of Physics: Condensed Matter, Vol. 21, No. 36, 2009, 364213).

Figure 4. The diamond’s infrared spectrum shows no detectable nitrogen-related absorption in the 800–1400 cm–1 range. The diamond absorption peak is at 1332 cm–1, while the peaks at 5785, 1263, 1124, and 437–669 cm–1 are unknown.

Figure 5. The diamond has a strong V0-GR1 center (741, 745 nm) and a weak (NVN)0 center (503 nm). The NV0 (575 nm) and NV– centers (637 nm) were not detected at liquid nitrogen temperature at either 325 nm (top) or 473 nm (bottom) laser excitation. The designation of the 505, 524, 668, 694, and 706 nm bands is unknown.
CLIPPIR diamonds sometimes exhibit infrared absorption at 3107 cm–1; this is a nitrogen-bearing (VN3H) defect (J.P. Goss et al., “Identification of the structure of the 3107 cm–1 H-related defect in diamond,” Journal of Physics: Condensed Matter, Vol. 26, No. 14, 2014, 145801). This diamond has no clear signature of infrared absorption at 3107 cm–1 or NV centers (PL: 575 and 637 nm). We believe that the cause of this is an extremely low level of nitrogen, below the detection limits of the instrument (figures 4 and 5). The lack of nitrogen in type IIa diamond is associated with less color in the diamond. This diamond has a strong V0-GR1 center (741, 745 nm) and no NV0/− (575 nm) and V0 (637 nm) centers (figure 5).
The CaSiO3-walstromite inclusion in this 3.0 ct diamond indicates a natural diamond from a very deep origin. @chapter:22 @chapter:1 @chapter:22


# Publication Year: 1991
# Title: An Examination of Nontransparent “CZ” from Russia
# Abstract: White, pink, and black nontransparent synthetic "cubic zirconia" is currently being manufactured in Russia and marketed primarily in cabochon and bead form. These unusual materials are potentially useful as substitutes for such gem materials as pearl, dyed black chalcedony ("onyx"), and even black diamond. The authors provide a detailed description of these new products, including the chemistry and probable manufacturing techniques. These products can be readily identified by standard gemological tests. @chapter:18 @chapter:1 @chapter:18


# Publication Year: -
# Title: Kunzite Journey of the Stone
# Abstract: This miner is handling a kunzite crystal at the Oceanview Mine in Pala, California, for the very first time since its formation. - Brendan Laurs

                      Few people outside the gem industry realize the true nature of a gemstone’s journey from the mine to the jewelry-store counter. Whether the gem is being offered to consumers at a traditional jewelry store, an internet shopping site, or a television broadcast, the journey always involves a great deal of effort. Tons of earth and countless hours of labor are needed to bring a gem from mine to market. @chapter:33 @chapter:2 @chapter:33


# Publication Year: 1990
# Title: Spring 1990 Gem News International
# Abstract: Tucson ‘90
            Beryl Triplet Cabochons
            Diffusion-Treated Corundum
            Star Ekanite
            Cat's-Eye Iolite
            Mother-of-Pearl Cameos
            Dyed Green Quartzite
            New World Sapphires
            Cat's-Eye Spinel
            Red Taaffeite
            Treated Paraiba Tourmalines
            Tanzanian Zircon
Diamonds
            Filled Diamond Update
            Computer Technology Enhances New Diamond Sorter
            Kimberlites Discovered in Canada
            Israeli-Japanese Joint Diamond-Polishing Venture
            Ghana Considers Private Mining
            Australians Develop New Technology for Diamond Exploration
Colored Stones
            New Amethyst Discovery in the Eastern United States
            Beryl Discovery in Finland
            New Find of Orthoclase
            California Star Quartz
            East African Spinels
            Oregon Sunstone Update
            Largest Known Faceted Liddicoatite Tourmaline Reportedly Found in Brazil
            Unusual Iridescent Zircon
Synthetics and Simulants
            Glass Imitation Emerald Crystal
            New Synthetic Ruby

To view the full section, download the PDF above. @chapter:27 @chapter:0 @chapter:27


# Publication Year: 2019
# Title: Glass-Filled Polki-Cut CVD Synthetic Diamonds
# Abstract: Figure 1. These “polkis” exhibiting a square profile, (0.27–0.29 ct) were identified as glass-filled CVD synthetic diamonds. Photo by Gagan Choudhary.

The term polki refers to a flat-cut diamond that is a simple and ancient form of today’s “rose cut” and has been popular in traditional Indian kundan-meena jewelry. Since most commercial-quality polkis are fashioned from flat rough crystals (macles, for example) or chips derived from the cutting of larger crystals, they often contain cleavages or fissures opening on the surface, making them even more delicate. In the past decade, the trade has been flooded with polkis filled with high-RI glass to improve their clarity as well as durability, and these have been widely used in kundan-meena jewelry.

Figure 2. Glass filling in the three polkis from figure 1 was indicated by color flashes along cleavages and fissures (left and right). Also note multiple parallel incipient and intersecting cleavage planes in the left image. Photomicrographs by Gagan Choudhary; fields of view 6.35 mm (left) and 5.08 mm (right).
Recently, the Gem Testing Laboratory (GJEPC) in Jaipur received three light gray to brown polki-cut diamonds (figure 1) with square profiles for identification. They weighed 0.27–0.29 ct and measured 6.86–7.41 mm long and 0.36–0.41 mm thick. The client informed us that the polkis were natural but wanted to know if they were glass-filled. On initial examination under a microscope, glass filling in all three was evidenced by color flashes (figure 2), typically blue, violet, and pink, along with some crackling effects within the fissures and cleavage planes in two directions, intersecting each other at almost 90° (octahedral cleavage in diamond). The presence of glass (containing lead and bromine) was further confirmed by energy-dispersive X-ray fluorescence (EDXRF) analyses. These polkis also displayed a few dark brown grains, some of which were associated with stress cracks. No attempt was made to identify the nature of these grains.
Considering our past experiences with polkis having square profiles, further tests were performed to determine a natural or synthetic origin. When viewed under crossed polarizers, all three polkis displayed a checkerboard strain pattern from the top and sub-parallel columnar patterns from the sides. Infrared spectra confirmed all three specimens as type IIa; DiamondView imaging displayed orange fluorescence, but no distinct growth patterns could be resolved. No phosphorescence was detected in any of the samples. Such growth patterns (under crossed polarizers) and fluorescence have been observed previously in CVD-grown synthetic diamonds by this author, as well as reported in the literature (e.g., P.M. Martineau et al., “Identification of synthetic diamond grown using chemical vapor deposition (CVD),” Spring 2004 G&G, pp. 2–25). Furthermore, photoluminescence spectra using 532 nm laser excitation revealed a distinct silicon vacancy–related peak at ~737 nm, even at room temperature (figure 3). This feature is widely used by gemological laboratories to identify synthetic diamonds (both CVD- and HPHT-grown).

Figure 3. The room-temperature photoluminescence spectrum of each polki sample, with 532 nm laser excitation, revealed a strong silicon-vacancy related feature at ~737 nm.
In the past we have seen numerous examples of polki-cut diamonds with glass filling, as well as many CVD synthetic diamonds fashioned as polkis. This was the first time we had encountered glass-filled CVD synthetic diamond polkis, though their market penetration is unknown. Although glass filling is not challenging to identify, encountering it in synthetic diamonds could lead to a misidentification as natural, especially among the trade. Since diamond polkis are usually fashioned from flat rough or chips derived during cutting larger crystals, they often display triangular or irregular profiles, while the polkis described here had a square profile. In view of this, square-shaped polkis offer the best yield for crystals with square profiles, such as natural cubic crystal or synthetic diamond crystals grown by the CVD process, which display a square and tabular habit. Therefore, this feature is quite useful in raising doubts, especially when mixed in parcels of polki-cut natural diamond. @chapter:36 @chapter:1 @chapter:36


# Publication Year: 2016
# Title: “Pond Life” Orbicular Chalcedony
# Abstract: Figure 1. “Pond Life,” a 50.95 ct orbicular chalcedony cabochon measuring 48.5 × 27.0 × 5.5 mm, evokes a pond. The “frog eggs” are actually iron-containing inclusions surrounded by the host’s concentric growth. Photo by Elise A. Skalwold.

	The seemingly infinite combination of growth features and inclusions seen in microcrystalline quartz fires the imagination, often evoking visual metaphors (see “Aurora Iris Agate” in this column). Such is the case with the orbicular chalcedony seen in figure 1. From a piece of non-descript tumbling rough purchased in 2011, Paul Stalker (Stones by Stalkers, Tioga, Pennsylvania) delighted in creating what he christened “Pond Life,” as the 50.95 ct piece’s polished appearance resembles frog eggs within a pond.

	Exploring the interior of such microcrystalline varieties of jaspers and agates can be just as fascinating as exploring inclusions within single-crystal quartzes, though these opportunities may be overlooked when dazzled by complex macro features. Orbicular chalcedonies such as this ocean jasper are particularly interesting. Here, iron-containing inclusions such as limonite, goethite, and hematite are surrounded by the concentric growth of the host material, which displays the unique fibrous texture found in some types of chalcedony (figure 2, left). Bundles of fibers composed of crystallites are combined with mutually complex optical orientations, giving rise to the eye-visible effect. While beautiful in transmitted, reflected, and polarized light, the addition of various contrast filters can dramatically enhance the details of these subtle growth features, making them easier to study, as well as creating stunning images of a specimen’s inner world (figure 2, right). For more on advanced filtering techniques, see Fall 2015 Micro-World, pp. 328–329.

	Figure 2. The use of a red contrast filter with transmitted light (left) dramatizes growth textures, making them easier to study than with unfiltered transmitted light (right) while creating an aesthetically pleasing image. Photomicrograph by John I. Koivula; field of view 4.0 mm. @chapter:26 @chapter:0 @chapter:26


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

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

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

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

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

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

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

	Pearls dangle from this diamond and cat’s eye alexandrite cabochon pendant.
Pearls were also popular during the Edwardian Era, and were often showcased in a piece of jewelry. Drop a pearl in a bed of diamonds or set it in platinum, and Edwardians thought this blazingly white-hot combination to be the height of sophistication and elegance. Although many of the customs of the Edwardian Era may seem to be a part of the distant past, the international success of Downton Abbey, the television drama whose first season was set in Edwardian England, proves that we are still fascinated by the time. And if you look around a jewelry store, you’ll see that Edwardian jewelry continues to influence contemporary designers. @chapter:20 @chapter:2 @chapter:20


# Publication Year: 2023
# Title: G&G Contributors Awarded for Best Geoscience Research
# Abstract: Diamond: Genesis, Mineralogy and Geochemistry, Volume 88 in the Reviews in Mineralogy and Geochemistry series, received this year’s Mary B. Ansari Best Geoscience Research Resource Award.
Several G&G authors and editorial board members are among those honored for their contributions to a recent volume in the Reviews in Mineralogy and Geochemistry series (see above). The Geoscience Information Society’s annual Mary B. Ansari Best Geoscience Research Resource Award recognizes the year’s outstanding reference publication or website. The 88th volume in the Reviews series, Diamond: Genesis, Mineralogy and Geochemistry is a comprehensive resource covering a wide range of diamond-related subjects. The publication is available for download at geoscienceworld.org and minsocam.org.
Congratulations to volume editors Karen Smit, Steve Shirey, Graham Pearson, Thomas Stachel, Fabrizio Nestola, and Thomas Moses, as well as G&G contributors Christopher M. Breeding, Jim Butler, Alan Collins, Ulrika D’Haenens-Johansson, Dorrit Jacob, Mandy Krebs, and Evan Smith for their chapters in the volume. @chapter:35 @chapter:1 @chapter:35