Publication Year: 2022 Title: Update from Mozambique’s Ruby Mines Abstract: Figure 1. Mining of the gravels at Mugloto pit 3 in the MRM concession. The gravel layer is around 30 cm thick. The material on top has a distinct reddish tint that is typical for sediments in tropical environments. Under the layer of gravel, the weathered basement rock is more grayish in color. Photo by Wim Vertriest; courtesy of MRM.
Mozambican rubies have revolutionized the dynamics of the ruby trade since their debut on the global gem scene in 2009. GIA has been following the evolution of the deposits around Montepuez in the Cabo Delgado Province of northern Mozambique since the very beginning (see W. Vertriest and S. Saeseaw, “A decade of ruby from Mozambique: A review,” Summer 2019 G&G, pp. 162–183). In August 2022, a GIA field gemology team visited the mining area to document the current state of mining and to collect samples for future studies.
In less than a decade, the balance has shifted from an informal environment dominated by artisanal miners and foreign buyers to a situation that is mostly under the control of large-scale miners who bring these rubies directly to the global market.
There are currently three of these major operations working in the area east of Montepuez.

Montepuez Ruby Mining (MRM): A partnership between Gemfields and local partner Mwiriti that has been mining rubies since 2012. Gemfields also mines Zambian emeralds at the Kagem mine.
Fura Gems: This company has been involved in Mozambican ruby mining since 2019. Some of their concessions were previously worked by Mustang Resources. Fura is also actively mining Colombian emerald and Australian sapphire.
GemRock: Owned by luxury jewelry brand DiaColor, this operation has been active on the ground since 2019.

In terms of geological formation, the ruby mineralization in the Montepuez area is not yet fully understood. The gems are generally described as amphibole-related corundum since the associated rocks are rich in amphibole. This mineral also dominates the inclusion scene of these gems.
While some primary mineralization is known and these ruby-bearing bodies are areas of interest for the mining companies, the rubies are seldom mined from the host rock. Nearly all of the mining activity is focused on the secondary deposits. These weathered gravel layers are rich in rubies and referred to locally as camada. This type of material is easy to mine, and the value of the ruby found here is higher than that in the primary deposits. The original host rock may contain higher volumes, but the majority of this corundum tends to be of very low grade. The exploration strategies of the mining companies focus heavily on identifying the extent, thickness, and distribution of the secondary gravels throughout their respective concessions. Understanding the geological formation of the corundum in this geological setting is a continuing process. Exploration teams are actively delineating and characterizing the ore bodies that hold the primary mineralization.
All three large-scale operations extract these ruby-rich gravels by stripping the overburden with excavators. This exposes the camada, which is dug up and stockpiled near the wash plants (figure 1). Local variations of the gravel layers can provide additional challenges. In some areas the sediment cover is less than 50 cm thick, which means the shallow gravel layer contains an abundance of roots, branches, and other organic material, making it harder to process further down the line. In other areas, the gravels are buried over 15 m deep, requiring serious effort and planning to strip the overburden. The ruby-rich layers themselves can vary from 10 to 150 cm; in some cases, multiple layers are present. The main one is always lying directly on the (extremely weathered) basement rock, which often consists of amphibolites, gneisses, and occasional felsic pegmatite veins.

Figure 2. The first step in the wash plant at Fura is the feeding bin (top left), where material enters the washing process. While the material moves down through the bins, water is added and a first screening removes large boulders. The trommel serves a dual function, breaking up clay lumps and screening out oversized materials. This image captures the first of seven steps to reduce the gravel to a concentrate rich in ruby, which is then handled in the sort house. Photo by Wim Vertriest; courtesy of Fura Gems.
While washing the rubies out of the gravel sounds very straightforward, this is a complex engineering process that requires careful monitoring and control. The gravels are unsorted, with quartz boulders up to 30 cm in diameter, but can also have a significant clay content. Processing them is no easy task and requires many steps of separating by size as well as various techniques to break up sediment clusters and concentrate the ore. Sizing is routine, but the other steps require considerable effort. At all of the large mining operations, logwashers, rotating trommels, and high-pressure water jets are used to break up clay clumps (figure 2). Concentration of the gravels (i.e., removal of the unwanted minerals) focuses on separating based on the specific gravities of the components of the sediment. Ruby is relatively dense compared to most other minerals such as feldspar and quartz. The most convenient method is using a pulsating jig where the waterlogged gravels move across a screen with barriers while getting pushed up vertically. This allows lighter materials to wash over the jig while denser minerals are concentrated at the bottom. While simple, this technique has its limitations, and several of the mines have progressed to more advanced techniques that allow for more precise separation and/or higher capacity, such as dense media separators and rotating pans in which a slurry with a precisely controlled density is used to separate heavier mineral fractions.
All of these techniques require large volumes of water. Plant operators assume that every metric ton of gravel processed requires 1000 liters of clear water. This water consumption was a decisive factor for development of the wash plant. For instance, a nearby river can serve as a cheap and constant supply of water, while boreholes are a much more costly alternative. As such, considerable effort is put into recycling water using settling ponds, cyclones, and flocculants. This allows much of the water, sometimes up to 90%, to be reused in the cleaning process.
With three large-scale mines operating in the area, the volumes of gravel processed are immense. The combined washing capacity of the three mines is more than 500 metric tons per hour.

Figure 3. At GemRock, the concentrate from the wash plant is fed onto a conveyor belt where teams of sorters handpick the rubies. The workers are using gloveboxes to prevent physical access to the stones. At the end of the shift, the rubies are collected and inspected. Photo by Wim Vertriest; courtesy of GemRock.
The final product coming out of the wash plant is an intensely concentrated mix of heavy minerals enriched in ruby, though considerable portions of garnet, iron oxides, and other minerals are still present. Initially simple techniques such as manual sorting were used to handpick the rubies from this mix. As these operations grew, however, more advanced technology has been applied. Optical sorting devices are able to recognize rubies by their fluorescence and separate them from the mix. Most mines use these devices nowadays, often with manual control of the rejects since the machines are not flawless. In a final step, the mix of rubies is graded based on clarity, color, and size. Some mines perform this detailed and specialized task at company headquarters, while others do so at the mine. During the final stages of concentrating the rubies, security procedures become increasingly strict. Automatic sorting and gloveboxes (figure 3) are used to avoid contact with the rubies. The final grading, which must be done manually by experienced specialists, is heavily supervised in secured spaces. This is one reason why some companies prefer to do this at their headquarters.
The further development and growing importance of these large-scale mining operations has also brought changes to the artisanal mining communities. These garimpeiros mined 100% of Mozambique’s rubies in the first years after the discovery in 2009. Only in 2014 did the first rubies from large-scale mining reach the international market, through an auction hosted by MRM. Not all of these small-scale miners are local; many traveled from other provinces in Mozambique or even from neighboring countries such as Tanzania. In recent years, the importance of the garimpeiro in Mozambique’s ruby market has been in decline. Legal codes were adjusted to make unlicensed mining a crime, allowing government officials to intervene with the artisanal mining activities that took place on the licenses of the large companies. As compensation, the government created areas designadas that were assigned to the artisanal miners. However, these are often small and nearly barren. At the moment, these areas cover an area of four square kilometers. The mining licenses secured by the large-scale mining companies cover over 2,000 square kilometers. Conflicts over mining rights have created considerable tension between established powers and the local communities. Some of these disputes are only now coming to light or are just beginning to be felt.
But the most drastic impact on the artisanal mining community has probably been the sanctions against the foreign buyers in the neighboring towns. Ruby buyers, mainly from Asia, have worked from offices near Montepuez to buy directly from the garimpeiros since 2008–2009, but their numbers have been drastically reduced in recent years. This has almost completely eliminated the main clientele for the artisanal ruby miners. During GIA’s visit in 2016, huge numbers of garimpeiros (tens of thousands of them) could be seen working and traveling throughout all the mining concessions east of Montepuez. During GIA’s recent 10-day expedition in August 2022, only 37 artisanal miners were seen in the same area. Most of the artisanal activity has moved farther east toward the city of Chiure, where the garimpeiros are mining more recent river sediments that are rich in rubies. Many have returned to their home villages, while some of the locals have found employment with the large mining companies.
The Cabo Delgado Province is currently experiencing social and political turmoil. Religious extremist groups under the name Ahlu-Sunna wa al Jama’a have been growing more violent. This has forced many people to abandon their villages and relocate to the southern reaches of the provinces, where the mines are located. One company reported that the number of people residing on their mining license increased from 1,500 to more than 20,000 in less than one year.
The local political structure also lacks the strength to successfully empower the local communities. All large-scale miners pay significant royalties and taxes to Mozambique’s central government. Unfortunately, many of these funds fail to reach the historically underprivileged communities surrounding the mines in the northern Cabo Delgado Province. This only amplifies social unrest. Many local projects have been set up by the large companies as part of their own corporate social responsibility programs, focusing on a sustainable food supply, transportation, and healthcare.
The last five years have brought dramatic change to ruby mining around Montepuez. Nowadays the dominant players are the larger operations and no longer the garimpeiro community with their associated trading network. These large-scale miners have immensely upgraded and professionalized their operations since their initial exploration and early mining phases. They have integrated more sophisticated techniques in both the gravel processing and the sorting. Larger fleets of machinery and fine-tuned wash plants allow huge volumes of ruby ore to be handled. This has resulted in a more stable ruby supply to the international markets.
However, the situation on the ground remains unstable, with social unrest growing in the wider areas where the ruby mining is happening. Only time will tell how this situation will evolve. @chapter:18


Publication Year: 2017 Title: Partially Hollow Tridacna Blister Pearls with Shells Attached Abstract: Figure 1. Two Tridacna species shells with blister pearls in the adductor muscle area. Top: The shell of the specimen submitted to GIA’s Bangkok lab weighs 2.36 kg and measures 32.0 × 21.0 × 11.5 cm. The blister pearl measures 52.0 × 47.5 mm (depth unmeasurable). Photos by Nuttapol Kitdee. Bottom: The shell of the New York sample weighs 806.40 g and measures 20.0 × 13.5 × 9.5 cm. The blister pearl measures 80.00 × 50.0 mm (depth unmeasurable). Photos by Joyce WingYan Ho.

GIA sees pearls of all types submitted to its global laboratories. Almost all of them are either loose or mounted in jewelry pieces; however, exceptions are occasionally encountered. The submission of a blister pearl or blister still attached to its shell is such an example (Winter 2015 Lab Notes, pp. 432–434). In January 2017, the Bangkok laboratory received an intact shell with a pearl attached near the adductor muscle area (figure 1, top). The item weighed 2.36 kg. The shell measured 32.0 × 21.0 × 11.5 cm, while the pearl measured 52.0 × 47.5 mm. At the same time and by sheer coincidence, another shell with a similar appearance and a pearl attached to the same area (figure 1, bottom) was submitted to the New York laboratory. This item weighed 806.40 g and the shell measured 20.0 × 13.5 × 9.5 cm, while the pearl measured 80.0 × 50.0 mm.

The exterior of the shell submitted to Bangkok exhibited a light brownish color and appeared roughly triangular in outline with a wavy pattern of thin ridges in rows, while the interior was white to cream with a porcelain-like surface. According to the client, the shell was found in 2014 by fishermen off the coast of Kood Island, a district of Trat Province in eastern Thailand. The shell’s features are characteristic of Tridacna species mollusks, of which there are a number of varieties (U.E. Hernawan, “Taxonomy of Indonesian giant clams (Cardiidae, Tridacninae),” Biodiversitas, Vol. 13, No. 3, 2012, pp. 118–123).

As figure 1 (top right) shows, a blister pearl of similar color is prominently attached to the surface. Observation with a loupe and microscope confirmed that it was naturally attached and untreated. Microscopic examination using a fiber-optic light source confirmed the presence of flame structure on some surface areas of the shell and pearl, confirming their non-nacreous or porcelaneous nature. The pearl’s flame structure was short and patchy, while that seen on the shell was sharper and more defined. While the pearl’s nomenclature may be the source of some debate, we considered it to be a blister pearl, rather than a blister, based on its external appearance, position on the shell, and size (E. Strack, Pearls, Ruhle-Diebener-Verlag, Stuttgart, Germany, 2006, pp. 115–127). The shell and pearl were exposed to long-wave UV, with the shell showing a moderate to strong chalky blue reaction with yellowish orange patches near the lip area (figure 2, left), while the blister pearl exhibited a weak to moderate yellowish green color (figure 2, right). This demonstrates how fluorescence in samples may vary from area to area.

Figure 2. Exposure to long-wave UV produced a moderate to strong chalky blue reaction with yellowish orange patches in the shell of the Bangkok specimen (left) and a weak to moderate uneven chalky yellowish green reaction in the attached blister pearl (right). Photos by Promlikit Kessrapong and Kwanreun Lawanwong.
However, the most noteworthy feature of the Bangkok specimen was that when the shell was tilted or gently rocked from side to side, a liquid clearly moved within the blister pearl (figure 3, left). The liquid was not viscous and so was most likely water, rather than a thicker liquid such as oil. It is possible that seawater was trapped during the blister pearl’s formation or found its way into the “hollow” pearl at a later date. When fiber-optic light was used to illuminate the blister pearl, some of the light was transmitted and made the pearl appear translucent (figure 3, right). This, together with the trapped liquid, proved the pearl was at least partially hollow (see video at http://www.gia.edu/gems-gemology/tridacna-blister-pearls).

Figure 3. The blister pearl on the Bangkok submission shows a distinct boundary delineating the two phases (liquid and air) within the hollow pearl. The liquid part appears as a darker area and the air as a lighter area (left). Fiber-optic illumination reveals the boundary from a different perspective (right).
To see the extent of the Bangkok blister pearl’s void, we examined its internal structure using a real-time X-ray (RTX) machine. Although it was only possible to examine the pearl in one orientation owing to its position and size, the blister pearl quickly revealed its partially hollow form (figure 4, left). The various shades of gray within the white near-oval feature (solid pearl surface) prove that the blister pearl’s interior is full of organic matter and/or air since the X-rays passed through with very little obstruction. While hollow or partially hollow pearls—both nacreous and non-nacreous—are not new (N. Sturman, “Pearls with unpleasant odors,” GIA Laboratory, Bangkok, 2009, www.giathai.net/pdf/Pearls_with_unpleasant_odours.pdf), this is the first one GIA has encountered with such visible trapped liquid. Although the solid shell attached to the pearl displayed similar gray shades, this coloring relates more to the sample’s thickness than anything else. A few small rounded, darker gray patches are voids caused by parasites boring within the shell rather than by structures within the blister pearl.

Figure 4. RTX results for the Bangkok sample (left) revealed a hollow pearl with a near-oval white ring marking the solid outline of the pearl’s surface. Only parts of the New York pearl (right) were in the field of view at any one time due to its size. Neither appears to be entirely hollow; however, it was not possible to examine the pearls in other orientations due to their size and position on their hosts.
Void-like structures in whole or blister pearls from Tridacna species mollusks are not unusual (S. Singbamroong et al., “Microradiographic structures of natural non-nacreous pearls reportedly from Tridacna (clam) species,” Proceedings of the 5th GIT International Gem and Jewelry Conference, Pattaya, Thailand, pp. 200–222), and GIA has examined many voids in other non-nacreous pearls. The RTX results proved that the specimen described was a natural blister pearl attached to its shell.

The shell submitted to GIA’s New York laboratory is also noteworthy, not only for the coincidental submission, but also because the pearl was larger relative to its host’s size than the one examined in Bangkok. The baroque natural blister pearl attached to this rather more colorful shell was also partially hollow, although not to the degree of the Bangkok sample. As the RTX results in figure 4 (right) revealed, the partially hollow blister pearl had a complex internal structure and was less homogenous than the specimen submitted in Bangkok. Unfortunately, no provenance was supplied with the New York sample, so there is no record of where it was found.

Both GIA reports stated that the naturally attached feature on each shell was a natural blister pearl. Many such specimens examined at GIA’s labs are submitted as loose examples that have already been removed from their hosts, so it was a welcome change to handle these two shells. In addition, a comment was included on each report informing the clients of the pearl’s partially hollow nature and, in the case of the Bangkok submission, the presence of a liquid. The size and appearance of the shells submitted proved they were not Tridacna gigas (giant clam), and the report referred to the hosts as Tridacna species only. @chapter:14


Publication Year: 2004 Title: Fall 2004 G&G Book Reviews Abstract: “Blood from Stones: The Secret Financial Network of Terror”
By Douglas Farah, 225 pp., publ. by Broadway Books, New York, 2004. US$24.95

“Starting to Collect Antique Jewellery”
By John Benjamin, 191 pp., illus., publ. by Antique Collectors’ Club, Woodbridge, England, 2003. US$25.00

“Starting to Collect Antique Silver”
By Ian Pickford, 192 pp., illus., publ. by Antique Collectors’ Club, Woodbridge, England, 2003. US$25.00

“Within the Stone”
By Bill Atkinson, 180 pp., illus., publ. by Browntrout Publishers, San Francisco, CA, 2004. US$39.95

“Gems and Jewels: A Connoisseur’s Guide”
By Benjamin Zucker, 248 pp., illus., publ. by Overlook Press, New York, NY, 2003. US$60.00

“The Tourmaline”
By A. C. Hamlin, 107 pp., illus., originally publ. by James R. Osgood & Co., Boston, MA, 1873; republished by Rubellite Press, New Orleans, LA, 2004, US$75.00

“The History of Mount Mica”
By A. C. Hamlin, 123 pp., illus., originally publ. by Augustus Choate Hamlin, M.D., 1895; republished by Rubellite Press, New Orleans, LA, 2004, US$85.00

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


Publication Year: 2015 Title: The Foldscope and Its Gemological Applications Abstract: Figure 1. A fully assembled Foldscope measures approximately 7 × 2.5 in. A toggled LED light source is tucked into tabs on the back, and the bottom center slit accommodates standard glass microscope slides. Photo by Kate Pleatman.

              The Prakash Lab of Stanford University, a small team of graduate students led by bioengineering professor Manu Prakash, has created a portable paper microscope called the Foldscope. Originally conceived for disease detection in remote areas, it was later expanded for educational use. The concept of the Foldscope won a $100,000 grant from the Gates Foundation in 2012 and a $50,000 first prize from the 2014 Moore Foundation Science Play and Research Kit Competition, which challenges participants to reinvent scientific tools of the past to attract a new generation of scholars. Speaking at the annual TED Conference in March 2014, Dr. Prakash announced that the concept was prototyped, functional, and could be manufactured for less than $1 each.

Submissions were accepted for a beta test group (now closed) named the “10,000 Microscope Project.” The goal was to get a Foldscope in the hands of 10,000 users worldwide, in medical and non-medical fields. The project requested users who understood microscopy and agreed to write detailed scientific studies based on their own research, to be collected and published to show the variety of potential uses. Seeing a major application in field gemology, this author requested and received a Foldscope.

Beta testers received Foldscope components and instructions in December 2014. The body is made of a material more like plastic than paper, to prevent tearing. Pieces are punched out of perforated sheets and assembled like origami (figure 1). The kit also contained interchangeable low-magnification (140×) and high-magnification (400×) lenses, a 3V LED toggled light source, and a surprise: a coupler to connect to a cell phone for photomicrography. Due to its complexity, assembling the Foldscope may take an hour or two. The device was ingeniously constructed, but would it work with gems?

Stones between 1 and 3 mm could be mounted onto glass slides for study. Larger stones were held with gem tweezers in the slide opening, to test whether the Foldscope would work with loose stones as well. Stones that were transparent and relatively small produced impressive results. The use of a binder clip to hold the slide or tweezers in place freed the hands to manipulate the focus more precisely. Focusing was the biggest obstacle, and late in the research the author inadvertently scratched a lens while trying to focus on a 1 mm corundum culet.

Figure 2. This photomicrograph of synthetic opal, taken using the high-magnification lens (400×), shows the characteristic cellular mosaic appearance. Photomicrograph by Kate Pleatman.
It was possible to clearly distinguish between natural and synthetic stones, because the magnification levels were exceptional (figures 2–4). Yet the small fixed size of the slide opening made it difficult to use with loose stones in tweezers, and gems more than 8 mm in depth could not pass enough light to view. Opaque material was not visible at all.

Figure 3. These fluid inclusions in quartz were taken using the Foldscope’s low-magnification lens (140×). Photomicrograph by Kate Pleatman.

Figure 4. These liquid inclusions in ruby are seen using the low-magnification lens (140×). Photomicrograph by Kate Pleatman.
Research details, photos, and feedback were sent to the Prakash Lab, along with design recommendations for making the device more ideal for gemological use. Suggestions included protection for the lens to prevent scratching and a larger gap for examining non-slide materials such as loose stones held with tweezers. An optional three- or four-inch fiber-optic light attachment would offer illumination from any angle, even for mounted stones. The Foldscope team has been very attentive to the feedback, although they have not committed to any alterations. Time will tell if the suggested modifications are feasible. No public release date or final price for the existing version has been announced. For more on this tool, visit www.foldscope.com. @chapter:29


Publication Year: 1983 Title: Summer 1983 Gem News International Abstract: Exhibits
            The Cleveland Museum of Natural History
            California Academy of Sciences
            Harvard University Mineralogical and Geological Museum
Announcements
            Kyoko Kojima wins the George A. Schuetz Design Contest.

To view the full section, download the PDF above. @chapter:7


Publication Year: - Title: GIA's Gübelin Gem Project: Various Gems, Sapphirine - Stibiotantalite Abstract: Sapphirine
Photo by Robert Weldon/GIA, courtesy Dr. E. J. Gübelin Collection
GIA Collection 33479

Among the collection assembled by Dr. Edward Gübelin are a number of uncommon gemstones from many worldwide localities. Documents, like the ones below, present information on gemstones that range from occasional use in jewelry to those that are quite rare and seldom faceted because of the lack of suitable starting material.

33479

			1.72 ct Sapphirine
			Sri Lanka (PDF)

34297

			24.03 ct Scapolite
			Brazil (PDF)

34659

			6.22 ct Scapolite
			Myanmar (PDF)

34144

			7.41 ct Scapolite
			Myanmar (PDF)

34597

			8.09 ct Scapolite
			Myanmar (PDF)

34603

			11.78 ct Scapolite
			Myanmar (PDF)

34136

			12.43 ct Scapolite
			Myanmar (PDF)

34712

			13.59 ct Scapolite
			Namibia (PDF)

34680

			40.80 ct Scapolite
			Namibia (PDF)

34146

			3.14 ct Scapolite
			Pakistan (PDF)

34897

			5.02 ct Scapolite
			Sri Lanka (PDF)

34894

			7.76 ct Scapolite
			Sri Lanka (PDF)

34149

			6.42 ct Scapolite
			Tanzania (PDF)

35049

			14.85 ct Scapolite
			Tanzania (PDF)

35035

			21.97 ct Scapolite
			Tanzania (PDF)

34150

			32.05 ct Scapolite
			Tanzania (PDF)

34102

			9.36 ct Scheelite
			Australia (PDF)

34099

			11.82 ct Scheelite
			China (PDF)

34472

			15.25 ct Scheelite
			Mexico (PDF)

34473

			17.05 ct Scheelite
			Mexico (PDF)

34884

			22.43 ct Scheelite
			Sri Lanka (PDF)

35510

			1.58 ct Scorodite
			Namibia (PDF)

34714

			2.12 ct Scorodite
			Namibia (PDF)

35502

			5.02 ct Sellaite
			Brazil (PDF)

35500

			5.11 ct Sellaite
			Brazil (PDF)

35506

			2.00 ct Siderite
			Portugal (PDF)

35505

			2.65 ct Siderite
			Portugal (PDF)

34014

			3.47 ct Sillimanite
			Myanmar (PDF)

34552

			11.16 ct Sillimanite
			Myanmar (PDF)

34535

			11.79 ct Sillimanite
			Myanmar (PDF)

34018

			2.62 ct Sillimanite
			Sri Lanka (PDF)

34887

			12.03 ct Sillimanite
			Sri Lanka (PDF)

34916

			18.86 ct Sillimanite
			Sri Lanka (PDF)

35589

			10.88 ct Sinhalite
			Sri Lanka (PDF)

34111

			11.24 ct Sinhalite
			Sri Lanka (PDF)

34892

			14.36 ct Sinhalite
			Sri Lanka (PDF)

34891

			18.50 ct Sinhalite
			Sri Lanka (PDF)

34104

			40.69 ct Sinhalite
			Sri Lanka (PDF)

34917

			45.68 ct Sinhalite
			Sri Lanka (PDF)

34716

			6.53 ct Smithsonite
			Namibia (PDF)

35512

			8.09 ct Smithsonite
			The United States (PDF)

35223

			9.11 ct Smithsonite
			The United States (PDF)

35511

			14.34 ct Smithsonite
			The United States (PDF)

35515

			5.74 ct Sodalite
			Namibia (PDF)

35405

			2.94 ct Sodalite - Hackmanite
			Canada (PDF)

34477

			5.82 ct Sphalerite
			Mexico (PDF)

34443

			26.21 ct Sphalerite
			Mexico (PDF)

34444

			39.02 ct Sphalerite
			Mexico (PDF)

34117

			11.05 ct Sphalerite
			Spain (PDF)

34114

			20.88 ct Sphalerite
			Spain (PDF)

34174

			21.81 ct Spodumene
			Afghanistan (PDF)

34169

			23.11 ct Spodumene
			Afghanistan (PDF)

34255

			55.50 ct Spodumene
			Brazil (PDF)

34175

			56.34 ct Spodumene
			Brazil (PDF)

34182

			7.26 ct Spodumene
			Locality not stated (PDF)

34176

			29.20 ct Spodumene
			Locality not stated (PDF)

34162

			17.09 ct Spodumene Kunzite
			Afghanistan (PDF)

34287

			22.98 ct Spodumene - Kunzite
			Brazil (PDF)

34417

			17.20 ct Spodumene - Kunzite
			Madagascar (PDF)

34161

			21.40 ct Spodumene - Kunzite
			Madagascar (PDF)

35150

			25.53 ct Spodumene - Kunzite
			The United States (PDF)

35529

			7.07 ct Stibiotantalite
			Locality not stated (PDF) @chapter:3


Publication Year: 2019 Title: Nathan Renfro Wins Royal Microscopical Society Award Abstract: A six-rayed star of golden rutile needles radiates from a black ilmenite core beautifully preserved in smoky quartz. Photomicrograph by Nathan Renfro; field of view 18 mm. Stone courtesy of the John Koivula Inclusion Collection.
GIA Carlsbad manager of colored stones identification and G&G regular contributor Nathan Renfro took second place in the Light Microscopy–Physical Sciences division of the Royal Microscopical Society’s biennial Scientific Imaging Competition. The award-winning image (see above) shows a rutile star in smoky quartz. @chapter:19


Publication Year: - Title: 2017 Vegas Outlook: Decent, But Cautious, Buying Abstract: Sotheby’s May 16 Geneva auction featured the Apollo Blue (14.54 cts) and Artemis Pink (16 cts) as an earring set. The pair drew a total of $57 million – $42.1 million ($2.9 million per carat) for the Fancy Vivid blue and $15.3 million ($958,000 per carat) for the Fancy Intense pink. Photo courtesy of Sotheby’s

First quarter U.S. retail jewelry sales showed a slight increase, according to the U.S. Department of Commerce figures, though most gains appeared to be at the higher and lower ends. Larger U.S. jewelry chains, which generally serve the middle class market, are expected to again report soft numbers for the first half of the year. Tiffany & Co. reported that its latest quarterly U.S. same store sales were 4% below the comparable period last year and Signet Corp., parent company to Kay Jewelers, Zales and Jared Galeria, said its first quarter sales plunged 11% compared to last year.

It’s likely that buyers at the upcoming June 5-8 JCK Las Vegas show will stick to their open-to-buy plans, but take relatively few chances on new lines or extra stock. Business at the boutique shows just before JCK should be a little stronger, however, because these shows are geared to the higher-end independent retailers who generally outperform the chains.

The results from the large retail jewelry chains, which have been lagging several percentage points below last year, show they are not immune to the difficulties confronting U.S. retailers these days.
RETAIL WOES
According to the Wall Street Journal (WSJ), some 8,600 retail outlets of all types are expected to close this year, a number surpassing the 2009 recession year. Entire shopping malls have closed or converted much of their retail space to non-retail activities, such as movie theaters and restaurants. While many analysts blame online shopping for some of the decline, clearly other factors are at work as well, as e-commerce sites have not been growing strongly either.

CEOs quoted in the WSJ article said fierce competition has kept prices low across the board, while costs rise. The CEO of Calvin Klein/Tommy Hilfiger noted that a pair of men’s dress pants costs less today than in 2007.

Consumers face increased costs of their own while wages remain stagnant. New cars, for example, are becoming less feasible for some would-be buyers, according to Michelle Krebs, a senior analyst with Cox Automotive. “It’s not just the price of the cars – it’s the price of everything else,” she said. “The price of things like health care, shelter – all of that is fighting for the budget.”
MODERATE MAY SIGHT
De Beers’ May cycle (sight) was moderate at $520 million, with apparently few additional deals struck outside the process. The total was about 12% below April’s cycle total of $586 million.

De Beers’ executives said in interviews that sales totals for the remainder of the year should be at “normal” levels following larger-than-expected allocations during the first quarter.

The early-year sales were directed mainly at some leading Indian manufacturers who had significantly cut their purchases late last year in response to the Indian government’s “demonetizing” higher denomination rupee notes. While the government action created some short-term turmoil in the country’s economy (many contractors and workers were paid in cash), business there adjusted much more quickly than expected.

The large sights made it possible for the company to clear a 6.7 million carat stockpile of lower value diamonds that had accumulated during the demonetization last year.

To further its “mine to market” initiatives to guarantee the supply chain of its diamonds, De Beers announced it would begin test-selling a wide range of qualities and sizes of polished stones in periodic auctions beginning in late June. The company said the test was to gauge demand for diamonds “with a clear and attractive source of origin” and “to offer the assurance of product integrity that dual certification provides.” The diamonds are graded by GIA and DeBeers gemological labs, according to a DeBeers’ press statement.
AUCTIONS
Prices for top gems at auctions have not continued at the record-breaking pace of the past few years where every sale saw a new benchmark, but they have remained solid.

The headliners for the spring season were a pair of fancy color diamonds sold at Sotheby’s Geneva on May 16: the GIA-graded Fancy Intense pink 16 carat (ct) Artemis Pink ($15.3 million /$958,000 per carat) and the 14.54 ct GIA-graded Fancy Vivid Apollo Blue ($42.1 million/$2.9 million per carat).

At Christie’s Geneva the following day, the 92 ct D flawless La Legende diamond brought in $14.98 million. The $163,000 per carat price was a record for a heart-shaped diamond, but well below prices that other large D flawless diamonds have achieved.

As reported last month, the auction season began with a record at Sotheby’s in Hong Kong: at $71 million the 59.6 ct Pink Star diamond was the most expensive gem ever auctioned. Its per-carat price of $1.2 million, however, was less than half of what similarly graded smaller diamonds have achieved at auction.

Prices for such top stones can vary widely because the market is thin at that level and is usually dependent upon two or three bidders running prices up after they pass the reserves. If even one of those buyers does not bid, then the prices can be 20% to 30% lower. @chapter:27


Publication Year: 2017 Title: Filled Calcite with Pronounced Phosphorescence Abstract: Figure 1. The calcite object (left, in daylight-equivalent light) showing a moderate green overall phosphorescence after short-wave UV exposure (right). The object emits a very strong whitish phosphorescence from one area, as seen in the center of the right image. Photos by Lai Tai-An Gem Lab.
Asterism, chatoyancy, color change, and play-of-color are phenomena that are caused by the interaction of light with the host’s structure or from its inclusions. Fluorescence, on the other hand, is the emission of light by a substance that has absorbed light or other electromagnetic radiation. Fluorescent materials immediately cease to glow when the radiation source is turned off; phosphorescent specimens continue to emit light for variable periods after the radiation ceases. Previous studies (Spring 2005 Lab Notes, pp. 46–47; Summer 2012 Lab Notes, pp. 139–140) have reported on the misnomer “night glowing pearls,” which are in fact not pearls at all but round rocks of mineral species that exhibit phosphorescence. Most of this material in the Chinese market has been treated in a variety of ways and in fact does not phosphoresce naturally.

A partially carved white ovoid with a greasy luster and golden paint within the low-relief carved features (figure 1, left) was submitted for identification to the Lai Tai-An Gem Lab. The submitting client claimed it was a “night glowing pearl.” The object weighed 796.71 ct and measured 48 mm in diameter. A spot refractive index reading of 1.59 and a specific gravity of approximately 2.66 indicated that the object was most likely calcite. This was later confirmed by Fourier-transform infrared (FTIR) and Raman (figure 2) analysis. Initial exposure to short-wave (254 nm) and long-wave (365 nm) UV light (cabinet and lamp respectively) failed to elicit any initial visible reaction; however, both short-wave and long-wave UV did initiate some fluorescence after about 15 minutes. When observed in a dark environment, moderate green phosphorescence lasting more than 10 minutes was noted, with strong whitish phosphorescence concentrated in one area (see figure 1, right).

Figure 2. Raman analysis identified the material as calcite (peaks at 279 and 1086 cm–1, blue trace). Cavities were filled with epoxy resin (peaks at 638, 1112, and 1608 cm–1, pink trace).
Microscopic inspection of the area showing the white phosphorescence revealed that the reaction originated from within the object, and did not emanate from the entire outer surface. The microscope revealed a few tiny bubbles comprised of solid epoxy resin (figure 3, left). This translucent epoxy acted as a plug to an opening into the (assumed hollowed out) interior, where a highly phosphorescent material was placed to create the calcite’s glowing effect. It was therefore understandable why this small capped area showed the strongest reaction (figure 3, right).

Figure 3. Left: Tiny bubbles were observed in the cavity under magnification. Field of view 6.2 mm. Right: The filled cavity showed stronger phosphorescence because the epoxy resin is more transparent than its calcite host. Field of view 11.6 mm. Photos by Lai Tai-An Gem Lab.
The trade name “night glowing pearl” used in Asian markets mostly refers to natural fluorite, but some fluorite is treated with a coating containing rare earth elements (REE) such as europium (Eu), dysprosium (Dy), or neodymium (Nd) to add or enhance phosphorescence. The sample submitted was calcite, consisting mainly of calcium, as confirmed by energy dispersive X-ray fluorescence (EDXRF). However, no Eu, Dy, Nd, or any other REE were detected, proving the material was not luminiferous. It therefore seems more logical that the phosphorescence originated from material below the ovoid’s surface.

It is interesting to note that the same client also submitted a jadeite jade sphere that was fashioned and treated in a similar manner. The cap on the jadeite piece used to plug the void was itself a piece of jadeite. Since destructive testing was not permitted on either item, analysis of their interiors was not possible. This technique of placing a phosphorescent material inside a hollowed-out stone object appears to be applicable to any material, so those in the trade should be aware when examining similar objects. @chapter:13


Publication Year: - Title: Be the Character You Are Abstract: Mary Todd-McGinnis, vice president of sales and e-commerce for Ben Bridge Jewelers, at the 2009 Jewelry Career Fair in Carlsbad. Photo by Kevin Schumacher/GIA

                      Mary Todd-McGinnis has worked for Ben Bridge Jewelers since the early 1980s and is vice president of sales and e-commerce. She shared her journey in the gem industry, pointing out the way trends and culture affect how people buy jewelry, at the 2009 Career Fair in Carlsbad. She used music, interest rates, fashion accessories and television shows as examples.

She also shared seven things she looks for in people that will make you “irresistible” to an employer:

1. Associate yourself with the best in the industry – GIA, WJA (Women’s Jewelry Association), AGS (American Gem Society), AGTA – “the best people travel in a clump and are very involved and active” in these groups.

2. Do your very best. “No matter what you’re given to do, do it better than anyone else is going to and you’ll always get recognized and you’ll always get ahead.”

3. Use Facebook and Twitter. “Make sure you’re putting out there the ‘you’ you want your employer or potential employer to see – because we will. Don’t have a second page that is the business you, because that’s not what this is about. Your customers or the people you do business with want to know who you really are. This is how we are transparent today; make sure you are appropriate.”

4. Be the character you are. “We all have unique and individual qualities that make us special – that make us funny, interesting, sweet, intelligent – figure out what that is and develop it to the max, because that’s the gift you’re going to give someone who’s going to pay you.”

5. Read, continue to learn. “You have to be good at so many things, especially in retail, where you have to be good with people, know gemology, be good with money, have a good business sense, and have customer service skills. You have to rely on people who are expert in only one area and suck the information out from them.”

6. Find out what makes you happy. “It’s a hard, deep, but important question that shows who you are.”

7. Show passion. “The people I’ve seen within any industry who are successful have a real passion for what they are doing. Find what you love to do and do it with everything you’ve got and you’ll have great success.” @chapter:36


Publication Year: - Title: Books: Kentucky Agate: State Rock and Mineral Treasure of the Commonwealth Abstract: By Ronald L. McIntosh and Warren H. Anderson, 216 pp., illus., publ., by University Press of Kentucky, Lexington, 2013, US$45.00.

                      From rough found in the streambeds of Station Stamp Creek to finished jewelry, the story of Kentucky agates, the official rock of the Bluegrass State, is told in words and shown with beautiful images.

The adventure starts in the first chapter, which offers 10 examples of agate types with descriptive names such as plume, moss, cloud, and flame. The photo meant to show moss and dendritic agate is not a good example, though, as the image did not clearly resemble moss on a rock of the branches of a tree, as described.

Chapter 2 explores when and where to find agates, as well as places where collecting is not permitted, such as Daniel Boone National Forest or the Natural Bridge State Park and River Gorge Geological Area, both of them scenic and popular spaces. Maps and photos of these locations are provided. The chapter also provides the names of gem and mineral shows, both within and outside the state, where agates are sold, as well as Kentucky colleges and museums with collections that are open to the public.

The formation and geology of agates are covered in the next two chapters. Chapter 3 features 16 photos of polished material, with captions describing the incredible colors and unique features of each sample. Chapter 4 includes a geologic map of the area where most Kentucky agates are found, along with the origins of their beautiful colors and banded patterns.

Microscopic features are described and shown in chapter 5. Under magnification, the causes of the unique features are more easily seen, and the captions offer additional details. For example, page 40 features an agate with heart-shaped banding, yellow limonite, and red hematite spherical inclusions. Ten of the samples are shown in reflected light, two in transmitted light, and another two in both reflected and transmitted light. The differences in appearance are striking, though it is unfortunate that the captions don’t list the magnification used.

The highlight of the book is chapter 6, featuring 255 photographs of cut specimens and slices. There are no more than two agates per page for over 149 pages. The backgrounds have been removed from the photos so the agates are seen against the white page, which makes the beautiful colors, patterns, and features even more breathtaking.

The final chapter features 11 examples of agate jewelry, with a photo displaying various agate cabochons. There is a refreshing mix of the traditional belt buckles and bolo ties alongside some very modern designs. One notable example is a tie clasp featuring a freeform polished agate with bold, contrasting colored bands of red and gray/black designed and created by Rachel Savané. Additional works are listed in the bibliography for readers interested in more information.

In this volume, Ronald McIntosh and Warren Anderson bring together an amazing collection of agates, professionally photographed with high-quality printing, creating a greater level of appreciation for these natural works of art. @chapter:7


Publication Year: 2022 Title: Unusual “Horsetail” and Columnar Inclusions in Demantoid Abstract: Figure 1. Fibers of serpentine were observed throughout this demantoid garnet in an unusual randomly curved pattern. Photomicrograph by Shunsuke Nagai; field of view 2.00 mm.
Demantoid, a gem variety of andradite garnet, sometimes contains “horsetail” inclusions, a type of fibrous inclusion commonly seen in demantoid from Russia (e.g., W.R. Phillips and A.S. Talantsev, “Russian demantoid, czar of the garnet family,” Summer 1996 G&G, pp. 100–111). Recent studies have shown that these horsetail inclusions from Russian demantoid are in fact hollow tubes partially filled with serpentine (e.g., A.Y. Kissin et al., “‘Horsetail’ inclusions in the Ural demantoids: Growth formations,” Minerals, Vol. 11, No. 8, 2021, article no. 825).
Recently, the authors had an opportunity to examine a unique yellowish green demantoid weighing 0.73 ct. Horsetail inclusions often occur in a radial form, but these were quite unusual, showing random spiral- or coil-like structures throughout the stone (figure 1). Raman spectroscopic analysis identified these inclusions as serpentine. While their formation remains an open question, horsetail inclusions may suggest complicated geological conditions such as decompression (again, see Kissin et al., 2021).

Figure 2. Columnar two-phase negative crystals containing mobile gas bubbles were another unique feature seen in the demantoid garnet. Photomicrographs by Makoto Miura; field of view 1.06 mm.
Also of interest in this stone were two-phase columnar negative crystals containing mobile gas bubbles (figure 2). Based on analysis of the OH stretching region of Raman spectra (e.g., M.C. Caumon et al., “Fused-silica capillary capsules (FSCCs) as reference synthetic aqueous fluid inclusions to determine chlorinity by Raman spectroscopy,” European Journal of Mineralogy, Vol. 25, No. 5, 2013, pp. 755–763; Winter 2015 Gem News International, pp. 446–448), these inclusions were determined to be mainly composed of saline solutions, possibly a mix of water and small amounts of sodium chloride, although the composition of the gas phase was not detected.
Fluid inclusions in demantoid garnet have previously been reported (again, see Winter 2015 GNI, pp. 446–448). However, the columnar shape of the two-phase inclusions seen here is quite unusual considering the cubic crystal system of the host andradite garnet. These two-phase inclusions could be related to the formation of hollow canals within the host demantoid in the presence of water, although we are not yet able to determine how these negative crystals formed in this peculiar shape. @chapter:4


Publication Year: 2017 Title: Two Unusual Natural Sapphires with Synthetic Ruby Overgrowth Abstract: Figure 1. A thin layer of synthetic ruby overgrowth with flux particles is distinct from the natural sapphire seed visible in the upper right of the image. Photo by Hollie McBride; field of view 1.99 mm.

The New York laboratory recently received two loose red oval mixed cuts for identification. Standard gemological testing yielded refractive indices slightly higher than expected for corundum: 1.778–1.788 and 1.776–1.787, while a typical RI for corundum is 1.762–1.770. Elevated RIs for chromium-diffused corundum have been reported and may be attributed to higher Cr2O3 concentration at the surface (S.F. McClure et al., “Update on diffusion-treated corundum: Red and other colors,” Spring 1993 G&G, pp. 16–28). To the unaided eye, the stones appeared to be chromium diffused, displaying red color concentration at the facet junctions, but their synthetic component became apparent upon further observation.

Microscopic examination revealed that planes of minute particles demarcated a thin layer, approximately 0.3 mm thick, of synthetic overgrowth from a natural sapphire core (figure 1). The presence of intact silk and heat-altered crystal inclusions confirmed the seeds to be natural (figure 2). A series of shallow flux-fingerprints cracking the surface suggested a flux growth process (figure 3). Portions of the near-colorless core could be seen in areas where the overgrowth was cut away during polishing (figure 4). These windows showed a sharp boundary without “bleeding” of the saturated red overgrowth into the near-colorless seed, which is typically observed in chromium-diffused corundum (McClure et al., 1993). The windows into the near-colorless seed also indicate that most or all of the red color is concentrated in the synthetic ruby overgrowth.

Figure 2. A fuzzy heat-altered crystal inclusion commonly referred to as a “snowball” is surrounded by a discoid fracture, proving the natural origin of the corundum seed. Photo by Hollie McBride; field of view 1.26 mm.

Figure 3. Reflective silk inclusions in the natural sapphire seed are visible behind a coarse flux fingerprint in the synthetic ruby overgrowth, which was cut through during the fashioning process. Photo by Hollie McBride; field of view 3.57 mm.

Figure 4. A portion of the near-colorless corundum seed is revealed in an area where the synthetic ruby overgrowth was cut away during fashioning. Photo by Hollie McBride; field of view 10.85 mm.
The overall appearance of the two stones was similar to the now-rare Lechleitner synthetic overgrowth emeralds, which are composed of a near-colorless beryl seed with synthetic emerald overgrowth. A sample with this type of synthetic emerald overgrowth was coincidentally submitted to the Carlsbad laboratory for identification around the same time (figure 5). In addition to emeralds, Lechleitner also experimented with ruby overgrowth on both synthetic and natural corundum seeds (K. Schmetzer and H. Bank, “Lechleitner synthetic rubies with natural seed and synthetic overgrowth,” Journal of Gemmology, 1988, Vol. 21, No. 2, p. 95–101), with the most commonly documented versions containing synthetic seeds (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Vol. 2, Opinio Verlag, Basel, Switzerland, 2005, p. 352; Fall 2014 Lab Notes, pp. 242–243).

Figure 5. A thin layer of synthetic emerald deposited on a near-colorless beryl seed, a type of synthetic emerald first marketed by Johann Lechleitner in the early 1960s. Photo by Hollie McBride; field of view 3.57 mm.
Advanced testing on the synthetic ruby overgrowth layer using laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) revealed the presence of Cr, Fe, Ga, Mn, Mg, Ni, Ti, Pt, and Zr (table 1). These results, specifically the presence of platinum, are consistent with previously reported synthetic ruby overgrowth (S. Saeseaw et al., “Analysis of synthetic ruby overgrowth on corundum,” GIA News from Research, June 10, 2015). Molybdenum was reported in the primary examination of Lechleitner overgrowth rubies (Schmetzer and Bank, 1988), and its absence here suggests alternative growth conditions for these samples.

Although this is not the first report of synthetic ruby overgrowth on natural sapphire seeds (Schmetzer and Bank, 1988; C.P. Smith, “Diffusion ruby proves to be synthetic ruby overgrowth on natural corundum,” Fall 2002 G&G, pp. 240–248), it marks the first time the New York and Carlsbad laboratories have had them submitted for identification. The resurfacing of these vintage overgrowth synthetics shows that once a material is in the trade, it is here to stay. @chapter:12


Publication Year: 2020 Title: A Sapphire with a Negative Crystal Containing a Mobile Graphite Daughter Crystal Abstract: This opaque hexagonal daughter crystal, of what is likely graphite, moves within the large negative crystal in the metamorphic star sapphire. Photomicrographs by Makoto Miura; field of view 4.0 mm.
Mineral and fluid phases within negative crystals in metamorphic sapphires provide us with general information on the sapphire and the trapped fluid itself. Such inclusions indicate a stone has not been heated when intact negative crystals are observed containing carbon dioxide (e.g., Fall 1986 Lab Notes, pp. 152–155). The author recently had an opportunity to identify a natural star sapphire containing a unique daughter crystal phase within a negative crystal.
This stone, which measured 22.20 × 18.00 × 14.05 mm with an estimated weight of 62 ct, was set in a ring. It displayed a six-rayed asterism due to light reflection from numerous long intersecting needles. Gemological observation and properties confirmed that this stone was a natural sapphire. The presence of unaltered mineral crystals and the chromophore cannibalization pattern around dense clouds of needles indicated the stone had not been heat treated (J.I. Koivula, “Internal diffusion,” Journal of Gemmology, Vol. 20, No. 7/8, 1987, pp. 474–477). Notably, this stone had one large negative crystal containing an opaque hexagonal crystal (see above). The hexagonal daughter crystal was free to move within the negative crystal when the stone was rocked and tilted. Careful infrared spectroscopic measurements suggested that this negative crystal was mainly filled with water and CO2 based on water-related peaks at 3706 and 3605 cm–1 and a large CO2 broad band at 2340 cm–1. However, the opaque daughter crystal was not identified by Raman spectroscopy because the negative crystal containing this daughter phase was located in a deeper section of the stone. Its hexagonal crystal shape and appearance suggested that the mobile hexagonal daughter crystal was graphite, which has been previously documented (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Vol. 3, Opinio Verlag, Basel, Switzerland, 2008, p. 268). This is the first example of a negative crystal with a mobile solid phase in corundum that the author has encountered. @chapter:19


Publication Year: 2016 Title: Update on the Scorpion Tsavorite Mine Abstract: Figure 1. The new production from the Scorpion mine includes these 6.48 ct and 3.43 ct tsavorites. Photo by Robert Weldon/GIA, courtesy of Bridges Tsavorite.

	At the AGTA show, Bruce Bridges (Bridges Tsavorite) detailed current activity at the Scorpion mine in Kenya and showed some new production (figure 1). The mine lay dormant for more than five years after the 2009 murder of owner Campbell Bridges, who originally discovered tsavorite. While waiting for the courts to hand down verdicts, the Bridges family and their employees were the target of numerous death threats. In January 2015, after four of the eight defendants received sentences of 40 years without parole, the mine reopened with a larger scale of operations than ever before.

	Activities expanded for a variety of reasons. As a corporation rather than a small family operation, the Bridges family felt that they were less of a target for criminals. The Bridges also found that the demand for tsavorite rose exponentially during the mine’s closure. With a limited supply and greater popularity, the higher selling price has made larger-scale mining more feasible.

	There are 80 to 100 workers at the Scorpion mine, three times the number employed when it closed in 2009. The miners work in continuous shifts seven days a week. Mechanization has increased to include more powerful generators and 15-kilowatt fans for ventilation in the tunnels. The tunnel is now below the oxidized zone, requiring a blast approximately every half meter of forward progress. The stronger fans allow the ventilation system to remove the smoke and dust in about two hours rather than the full day previously needed. They have also invested heavily in trucks, buildings, jackhammers, drills, and more explosives. Campbell Bridges’s original campsite and tree house remain intact.

	The main focus of the current operation is the Bonanza tunnel, also called tunnel 4, which was Scorpion’s most prolific tunnel in the 1980s. They are also working the adjacent tunnel 2, the largest producer in the 1990s. Tunnel 2 produced five kilograms of facet-grade material over one carat from one pocket during this period. A few kilometers from Scorpion is mine GG2, which typically produces tsavorite with lighter tones. GG2 is an open-cast operation on a hill, with plans to move into a tunnel phase later this year. An untouched surface deposit near tunnels 2 and 4 is also in development for open-cast mining, and the Bridges have high hopes for it, as the ratio of yield to waste is high on new deposits. Other sources include GG3, which is several kilometers away and primarily uses tunnel mining, and Snake Hill, which is one kilometer from Scorpion and has been mined by both open-cast and tunnel methods. Snake Hill is also a tanzanite source. These deposits have been put on hold in favor of tunnels 2 and 4 and GG2, as well as the untouched surface deposit.

	There is now greater sophistication and manpower in Bridges Tsavorite’s mining process. The drill team bores large holes in the tunnels and then places the explosives. After the blast, the air is flushed out by the new ventilation system. The removal of waste has been accelerated by the use of a mono winch, which allows up to eight tons of waste to be removed hourly. The waste is hauled to the dump site, where it is separated from the rock face. The mine manager examines the rock face for tsavorite crystals or nodules, also checking for indicators in the reef such as calcite, quartz, and pyrite. Depending on the indications, teams will either continue blasting or extract material with hammer and chisel until the gem body is reached. At that point, miners use sharpened six-inch nails and finally their hands. The gem-bearing specimens are bagged and marked for quality. Once out of the mine, the material is washed and the tsavorite crystals are separated from the host rock. Sieves are used to sort the production by size before it is graded on a sorting table (figure 2). It is then bagged, sealed, and taken to Nairobi by ground or air, depending on its value.

Figure 2. Prior to cutting, the Bridges operation sorts the tsavorite rough into categories by size, color, clarity, and shape. Photo courtesy of Bridges Tsavorite.

	All rough that can be cut to yield a 50-point stone or higher will be cut in-house in Kenya, while the cutting of smaller rough is outsourced. Campbell Bridges learned to cut gemstones in Idar-Oberstein, Germany, and he later trained local Kenyans. One expert cutter on-site is cutting at least 200 stones a month. The Bridges family is proud of their high cutting standards and that they cut most of the high-quality rough in Kenya (figure 3). They also pay a higher export value for finished cut stones than rough, generating more revenue for Kenya. The stones are exported to Bridges Tsavorite’s main sales office in Tucson or to customers worldwide.

	Even with the new investment and expenses, current production is only about 10% higher than before the mine was closed.  Electromagnetic surveys have shown extensive anomalies that indicate tsavorite enrichment zones. Most experts believe the reserves are very good, and Campbell Bridges himself believed he could follow the lines of the Scorpion mine’s saddle reef structure and the nose of the folds for two kilometers while producing tsavorite in pockets. Each tunnel at Scorpion is about 200 meters deep. These reserves must be balanced, however, with the growing cost of delving every meter further into the earth.

Figure 3. The Bridges intend to keep their tsavorite cutting in Kenya for as long as it is economically viable. Photo courtesy of Bridges Tsavorite.

	Bruce Bridges told us that “demand is through the roof” for tsavorite. With its popularity potentially on the rise, Bridges Tsavorite will have to outsource rough. Melee demand is at an all-time high, particularly in China and other Asian countries, where it far exceeds the available supply. Mr. Bridges foresees overall growth for tsavorite through television sales, but he wants to keep as much cutting in Kenya as possible. Challenges for the company include possible changes in the political scene, mining regulations, and the threat of crime and violence. Upon returning to Kenya, Mr. Bridges reported to the authors that death threats had started again. @chapter:24


Publication Year: 2018 Title: Aquamarine from Pakistan Abstract: Figure 1. Map of the Gilgit-Baltistan region in northern Pakistan showing the main aquamarine deposits of the Hunza, Braldu, and Shigar Valleys.
In recent decades, a steady supply of aquamarine has come from northern Pakistan, an increasingly important mining locality. The aquamarine was mined mostly from the Gilgit-Baltistan region, including the Shigar Valley, as well as the Hunza and Braldu Valleys (figure 1). The aquamarine occurs in zoned pegmatites formed by hydrothermal fluids in the cavities or veins (M.H. Agheem et al., “Shigar Valley gemstones, their chemical composition and origin, Skardu, Gilgit-Baltistan, Pakistan,” Arabian Journal of Geosciences, Vol. 7, No. 9, 2014, pp. 3801–3814).

Figure 2. The aquamarine crystal on feldspar from the Shigar Valley in Pakistan measures 17 cm tall. Photo by Joe Budd, courtesy of Arkenstone.
Most aquamarines from northern Pakistan show a long hexagonal prism habit and can reach up to a dozen centimeters in length (figure 2). Albite, muscovite, and tourmaline (schorl) are commonly associated as matrix, and most of these are collected as mineral specimens. Parts of them are gem quality and suitable for jewelry use.

Aquamarine samples from the Shigar Valley were obtained from local merchants who deal with Pakistani material. The samples displayed colors ranging from pale greenish blue and pale blue to nearly colorless, with a translucent to transparent appearance. The samples measured 1–2 cm in length and 0.5–1 cm in diameter. To explore the gemological and other properties of these samples, six of them (figure 3) were investigated by standard gemological methods as well as spectroscopic and chemical analyses at China University of Geosciences (Wuhan).

Figure 3. Six rough and two faceted aquamarines from Shigar Valley. The rough samples range from about 5 to 10 ct. The round brilliant cut weighs 3.82 ct, the square cut 7.91 ct. Photo by Yang Hu.
The following gemological properties were recorded: refractive index (RI)—no = 1.574–1.580, ne = 1.569–1.575; birefringence—0.005–0.006; specific gravity (SG)—2.60–2.72; UV fluorescence—weak bluish white to both long- and short-wave UV. The moderate to weak dichroism observed was a relatively saturated blue or greenish blue along the e-ray and very pale blue, greenish blue, or near-colorless along the o-ray.

Microscopic observation revealed abundant 20–300 µm inclusions, either two-phase (fluid, gas) or three-phase (one or two types of fluid, solid, gas) with various shapes. The irregularly shaped multiphase inclusions often gathered together to form a complex “fingerprint” network distributed along healed fissure planes (figure 4, top row). In addition, two-phase inclusions with elongated shapes parallel to the c-axis, and with hexagonal outer profiles perpendicular to the c-axis, were consistent with the crystalline symmetry of beryl (figure 4, bottom row).

Figure 4. Multiphase inclusions in aquamarines from Shigar Valley. Top: Abundant two-phase and multiphase inclusions with irregular shape showing complex “fingerprint” networks. Bottom left: An elongated two-phase inclusion parallel to the c-axis. Bottom right: The same inclusion (shown in the bottom left image) viewed down the c-axis, presenting a perfect circular gas bubble and hexagonal outer profile consistent with the crystalline symmetry of beryl. Photomicrographs by Yang Hu.
These two kinds of multiphase inclusions formed by different crystallization processes. When the beryl crystallized out of a hydrothermal fluid, some of the fluid was trapped. With dropping temperature during mineralization, beryl was re-deposited and a gaseous phase was released from the fluid, gradually forming single multiphase inclusions whose shape conformed to beryl’s hexagonal symmetry. But the formation of multiphase “fingerprint-like” inclusions with irregular shape occurred later. Fluid was embedded in the fracture of the beryl crystal. Due to the solution and re-deposition of beryl from fluid on the fracture surfaces, a small amount of liquid and released gas were gathered and closed off, just like “fingerprint” or dendritic growth networks along healed fissure planes. For a detailed description of these processes, please refer to E. Roedder, “Ancient fluids in crystals,” Scientific American, Vol. 207, No. 4, 1962, pp. 38–47.

Large amounts of multiphase inclusions could lead to a misty, translucent, and uneven appearance, such as the aquamarine crystal in figure 2, with a misty translucence toward the bedrock end. Generally, these characteristics can also be seen in aquamarine from other deposits in Brazil, the United States, South Africa, and China (D. Belakovskiy et al., Beryl and Its Color Varieties: Aquamarine, Heliodor, Morganite, Goshenite, Emerald, and Red Beryl, Lapis International LLC, East Hampton, Connecticut, 2005).

Multiphase and mineral inclusions were identified by Raman spectroscopy with 532 nm laser excitation. The gaseous phase was identified as a mixture of CO2 and a small amount of methane (CH4), and the fluid inclusion consisted of water with dissolved CO2 or liquid CO2. Solid phases inside the multiphase inclusions were identified as solid sulfur and orpiment. Along with columnar tourmaline, white albite, and flaky muscovite, other mineral inclusions such as orange-red almandine, brown tantalite, and yellow argentojarosite [AgFe3(SO4)2(OH)6] were identified by Raman.

Chemical analysis on aquamarine samples by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) showed the following ranges for alkali elements: Li 70–1240 ppmw, Na 830–3970 ppmw, K 54–453 ppmw, Rb 10–64 ppmw, and Cs 310–3220 ppmw. The amount of total alkali content including Li, Na, K, Rb, and Cs ranged from 1296 to 6033 ppmw. As alkali ions (mainly for Na) were associated with “type II” water molecules in structural channels (D.L. Wood and K. Nassau, “The characterization of beryl and emerald by visible and infrared absorption spectroscopy,” American Mineralogist, Vol. 53, No. 5, 1968, pp. 777–800), the relatively low Na content was in agreement with the low peak intensity of “type II” H2O revealed by Raman and IR spectroscopy. The low concentration of alkali content and lack of “type II” water in our aquamarine samples were similar to that in aquamarine from Italy and Vietnam (R. Bocchio et al., “Aquamarine from the Masino-Bregaglia Massif, Central Alps, Italy,” Fall 2009 G&G, pp. 204–207; L.T.-T. Huong et al., “Aquamarine from the Thuong Xuan District, Thanh Hoa Province, Vietnam,” Spring 2011 G&G, pp. 42–48). The chromophore Fe, responsible for blue color, was the richest among all transition elements between 1350 and 5080 ppmw; the samples showed the typical iron absorption at 375, 425, 620, and 820 nm in UV-Vis-NIR spectra. Transition elements V and Mn were present at 1–33 ppmw and 17–56 ppmw, respectively, and the bluish white fluorescence mentioned above may originate from Mn2+ or VO4 centers (M. Gaft et al., Modern Luminescence Spectroscopy of Minerals and Materials, 2005, Springer Berlin, pp. 97–99). Chemical and spectral characteristic suggested the Pakistani samples were low-alkali aquamarine colored by Fe ions rather than irradiation (i.e., Maxixe beryl). @chapter:0


Publication Year: - Title: Gemfields Inaugural Rough Ruby Auction in Singapore Abstract: Gemfields held its first Mozambique rough ruby auction in Singapore, where buyers from around the world came to bid on parcels. Photo by Andrew Lucas, ©GIA.

                      When you travel the world researching the industry, from time to time you experience a moment that you realize could be historic. This was the case in Singapore, where the first Gemfields rough ruby auction was held, with material from the Montepuez ruby deposit in Mozambique. While watching the buyers go through the lots offered for bidding, while at the same time observing the auction’s expert organization, we knew we might be witnessing the dawn of a change in the way the ruby industry does business.

The inaugural Mozambique ruby auction in Singapore has the potential to alter how rubies change hands in the market. Photo by Vincent Pardieu, ©GIA.
The auction marks a turning point in the way rubies are coming into the market. For the past 20 years, the Mong Hsu deposit in Myanmar (formerly Burma) was the world’s main source of rubies. Today, most of the rubies found in gem markets in Thailand (the global hub for ruby trading, processing, and cutting) come from the Montepuez area in Mozambique. Since the 2009 discovery of ruby deposits there, Montepuez has emerged as the world’s most active ruby mining area—though the stones that have reached the market thus far have all been mined illegally and smuggled out of Mozambique.

Now, for the first time, the legal owners of the mining license in Montepuez have introduced their product into the marketplace at auction. This development has stirred up excitement (leavened with some fear) in both Thailand and India, signaling as it does a seismic shift in the way rubies will enter the market. This groundbreaking event took place between June 12 and June 17, 2014. It was held in Singapore, considered one of the world's easiest countries for doing business. The source of the rough was Montepuez Ruby Mining Limitada. Gemfields had proposed acquiring a 75 percent interest in this deposit on June 8, 2011, and completion of the acquisition was announced on February 27, 2012. A 25-year mining license was issued at that time. Bulk sampling began in November 2012. By March 3, 2014, the mine had produced 8.2 million carats of ruby and other corundum. As of the auction date, Gemfields’s total expenditures at the Montepuez mine had reached US$34 million, including costs of acquiring the mining rights.

The bulk sampling by Gemfields of the Montepuez ruby deposit produced parcels of rough for auction that covered a wide range of qualities and sizes. This parcel contained 6,820 grams of untreated ruby rough. Photo by Vincent Pardieu, ©GIA.

	Gemfields
Gemfields (GEM) is a publicly traded company listed on the AIM market of the London Stock Exchange, where it is a constituent of the AIM50 index. In July 2008, the company acquired a 75 percent interest in the Kagem mine in Zambia, one of the world’s principal emerald-producing mines. In July 2009, Gemfields held its first rough emerald auction. Since then, the company has held 15 auctions of rough emeralds from its Kagem mine as well as two auctions of emeralds from other sources. Its total revenue for all emerald auctions to date is US$282 million. All together, sales for the financial year ending June 30, 2014, including emerald rough as well as ruby rough from the June auction, exceeded US$143 million.

Gemfields also owns other mining interests, including 50 percent of the Kariba amethyst mine in Zambia and licenses in Madagascar for ruby, sapphire, and emerald deposits. Gemfields acquired the Fabergé luxury jewelry brand in January 2013, giving the company a position in the luxury colored gemstone market.

	Covering the Auction
At the auction, the GIA team examined and evaluated several ruby lots offered for sale. We also interviewed Gemfields staff directly involved in the grading and creation of the lots and in setting up and operating the auction, as well as more than two dozen auction attendees.

The GIA team spent many hours examining the parcels of ruby available at the auction. Vincent Pardieu is evaluating a rough ruby parcel with Assistant Product Manager for Montepuez Ruby Mining Philippe Ressigeac. Photo by Andrew Lucas, ©GIA.
As a result of their emerald auctions, Gemfields is very experienced in auctioning rough gemstones, so the actual viewing and buying process was no mystery to most of the buyers. Gemfields followed the auction process as previously, refined over the years by inviting attendee feedback. Even some attendees who were new to the Gemfields system had an idea of what to expect at this auction.

GIA’s Andrew Lucas (left) consults with Gemfields Product Director Adrian Banks. Photo by Vincent Pardieu, ©GIA.
About 60 different companies attended, mainly from Thailand and India, but Gemfields also invited firms from the United States, Germany, France, and Switzerland. Most of the buyers were interested in how the lots were graded and arranged. The overwhelming feedback we received was that Gemfields did a very good job, considering this was the first time they had graded rough ruby parcels. All the buyers we spoke with felt the grading and lot organization were good, and most were very pleased. While some buyers would have made some changes to the organization of the lots, they all said any such changes would have been to suit their own business models. They felt the organization of the lots was fair for both the buyers and Gemfields’s interests.

Buyers spent considerable time grading and evaluating the rough ruby parcels at each booth before placing their bids. Photo by Vincent Pardieu, ©GIA.
At the Montepuez deposit, Gemfields recovers both primary and secondary ruby rough and uses two grading criteria, one for each type of deposit. Generally, the material from the secondary deposit is cleaner than that from the primary deposit. Gemfields said it took an average of two weeks to sort a lot of high-quality ruby rough, and six weeks for low-quality ruby rough. Gemfields grades rough by color, clarity, size, and shape. The Montepuez deposit produces ruby rough of all qualities for all market sectors: premium stones fine enough to be faceted without treatment, rough material to be heated with or without flux, and rough material to be treated with lead glass.

	Comparing Singapore and Myanmar Auctions
A few of the buyers interviewed also regularly attend rough ruby auctions in Myanmar. It was interesting to hear them compare the two auction systems and how the differences affected their buying. They all said the Gemfields auction featured more sophisticated grading criteria, and the lots were better organized by size and quality. Far more lots were offered there than at the Myanmar auctions, and they were broken down into narrower categories of detailed size and quality ranges.

Unlike Singapore, the Myanmar auction allows bids to be placed on one lot at a time. The results are declared before bids have to be submitted for the next lot. This allows buyers to know if they were successful on the first lot before bidding on the next lot, and so on. At the Gemfields auction, buyers had to submit bids for any lots they were interested in ahead of time. This meant buyers had to place bids on lots knowing that they might exceed their available capital if they were successful on most of their bids.

The Gemfields auction offered 32 tables in white booths, with daylight and torches available for examining rough ruby parcels. Buyers waited at tables for their turn to examine their chosen parcels. Photo by Andrew Lucas, ©GIA.

	Auction Logistics
The Gemfields auction offered 32 tables with similar natural lighting conditions and a total of 62 rough ruby lots. Buyers had a schedule book listing the bid schedules available at each table. When a table was free, interested buyers would sit and go through the lots in the bid schedule at that table. Each auction book page listed bid schedule, table number, disclosure of any treatment, numbered lots included in that bid schedule, Gemfields grade, gram weight or millimeter size range, number of pieces and total weight for that lot, and total number of pieces and total weight for the entire bid schedule. There were also sections in the book for buyers to list their own graded price per gram and total price in US$ for each lot in the bid schedule, as well as the price they would bid for the entire schedule. At the bottom of each page was a space for the company name, bidder’s name, bid amount in US$, and the amount again to be written in words. Buyers submitted bids by filling out and signing the page.

The parcel labeled “schedule-C at table 2” was composed of five pieces of fine-grade untreated ruby rough. Each weighed over 4 grams, for a total of 22.93 grams. Photo by Vincent Pardieu, ©GIA.
The lots were clearly created to attract existing ruby dealers with treatment expertise as well as new ruby buyers. Some lots were already treated. The treatments included lead-glass filling for lower-end material, as well as heating with borax for flux-assisted healed fissures. These lots were meant for manufacturers without expertise in ruby treatment. The same types of material were offered in untreated lots for those who preferred to do their own treatment. There were also higher-end lots of untreated material.

Some of the parcels of rough ruby had already been enhanced. This lot was heated with borax to enhance color and heal fissures. This gave buyers the option to bid on already-enhanced parcels or on similar but untreated material. Photo by Andrew Lucas, ©GIA.

	Outcome
Overall, the auction was a resounding success. Fifty-five companies placed bids, a record number for any Gemfields auction. Fifty-seven of the 62 offered lots were sold, a total of 91 percent by value and 90 percent by weight. Out of the 2.03 million carats of rough ruby offered, 1.83 million carats were sold. The total revenue generated was US$33.5 million. The total expenditure by Gemfields into the Montepuez mine was US$34 million by the time of the auction.

Auction buyers were satisfied. The Gemfields crew seems to have set reasonable reserve prices on the lots, and failure to reach the reserve price was not an issue. Gemfields seemed very open to feedback from the buyers on the auction process and the grading of lots for sale. Gemfields expects to narrow the invited companies down from 55 to somewhere in the 30s. They will use auction results to determine which companies to invite back on an ongoing basis. The next ruby auction is expected to take place before the end of 2014.

	The auction workbook, with bid schedule pages, proved very useful to auction
	attendees for viewing and evaluating lots and placing bids.

Table 1. Auction Results Summary

Auction Results (Ruby and Corundum)

June '14 Auction

					Dates

					12-17 June 2014

					Location

					Singapore

					Type

					Rough ruby and corundum

					Carats offered)

					2.03 million

					Carats sold

					1.82 million

					No. of companies placing bids

					55

					No. of lots offered

					62

					No. of lots sold

					57

					Percentage of lots sold

					92%

					Percentage of lots sold by weight

					90%

					Percentage of lts sold by market value

					91%

					Total sales realized at auction

					US$33.5 million

					Average per carat sales value

					US$18.43/carat

	Conclusion
The colored stone industry has been moving toward companies with greater investments in mining and more vertical integration through the value chain. Although most global colored stone production still comes from artisanal and small-scale mining, larger companies with deep pockets are now strategically positioning themselves. Gemfields’s first Mozambique ruby auction follows their successful emerald auctions in establishing an organized and transparent process for rough colored gemstones to reach the market.

The Gemfields staff worked closely with GIA team members to ensure that the story of this first Mozambique ruby auction was shared. Photo by Vincent Pardieu, ©GIA.
With the success of these auctions, it’s very possible the trend will spread. Governments of gemstone-producing countries may see the benefits of a transparent system for legally obtaining their fair royalties in exchange for their countries’ rich gemstone resources. These factors can promote transparency in gemstone marketing, in a world where scrutiny is intensifying. @chapter:28


Publication Year: 2023 Title: Cultured Pearl Market Update Abstract: Figure 1. Near-round to round small freshwater bead cultured pearls (approximately 2–4 mm) were widely available at the AGTA show in various colors including white, pink, purple, and orange. Photo by Artitaya Homkrajae; courtesy of Betty Sue King, King’s Ransom.
At the AGTA show, we spoke with several pearl dealers to acquire some insight into the current cultured pearl market. With demand for pearls trending upward in the secondary market, as reported by The Real Real in its Luxury Consignment Report in January 2023, it was easy to spot similar trends in other areas of the pearl market as well.
Bead cultured (BC) pearls are the result of the deliberate insertion of a bead nucleus along with a small piece of mantle tissue into the gonad of a living host mollusk to start the growth of the cultured pearl, a process known as nucleation or grafting. Non-bead cultured (NBC) pearls need only a piece of tissue implanted into the gonad or mantle of a host mollusk to form. A technique originally developed and successfully operated in Japan before adoption by other global operations including Australia, the Philippines, Indonesia, French Polynesia, and China, the nucleation process is intricate and requires expertly trained technicians.
The pearl industry, like others, was adversely affected by the COVID-19 pandemic. Many dealers noted a supply shortage of the main types of cultured pearls: South Sea, Tahitian, akoya, and freshwater. According to dealers, many pearl farms, especially Tahitian, use Chinese and Japanese technicians to perform the critical nucleation step. Due to travel restrictions and border closures during the pandemic, many experts were unable to travel to these locations, resulting in smaller harvests since 2020. In some farming areas, there were not enough employees on-site to keep the mollusks in good health, and thus the mortality rate was high. Assuming grafting returned to normal levels by 2022, a greater influx of supply is expected in 2024, given the typical 24-month growth periods. Some dealers added that strong demand for cultured pearls from Chinese and other Asian consumers is contributing to the current global shortage.

Figure 2. Left: Small round freshwater bead cultured (BC) pearls (top group of strands) and small round Japanese akoya BC pearls (bottom strands) appear very similar at first glance. Right: Upon closer inspection, the freshwater pearls more often show a rounded flat surface feature. Photos by Artitaya Homkrajae and Lisa Kennedy; courtesy of American Pearl Company Inc.
Small freshwater BC pearls from China (approximately 2–4 mm) were more widely available at the show than in past years, in near-round to round shapes and in various colors including white, pink, purple, and orange (figure 1). Freshwater cultured pearls of this particular size are typically NBC, normally oval (a potato-like shape), and can look similar to white saltwater Japanese akoya BC pearls of the same size. However, Gina Latendresse of American Pearl Company Inc. (Nashville, Tennessee) demonstrated that upon closer inspection, the freshwater pearls more often show a rounded flat surface feature on an otherwise spherical pearl, a feature usually too small to affect basic shape (figure 2). This feature is also occasionally observed in other types of freshwater cultured pearls.

Figure 3. Vietnamese akoya bead cultured pearls in various colors ranging from silver to light gray to light bluish gray. The pearls were said to be unprocessed and untreated. Photo by Lisa Kennedy; courtesy of Eliko Pearl Company.
Eliko Pearl Company (New York City) displayed numerous strands of Vietnamese akoya BC pearls with bodycolors ranging from silver to light gray and light bluish gray with exceptional orient (figure 3). These provide a greater selection of colors compared to traditional akoya BC pearls. Some white, light cream, and  cream pearls were also presented as unprocessed and untreated—steps normally used to improve appearance and alter color. However, many akoya BC pearls in the market have been processed to generate a classic white appearance. Vietnam has produced saltwater cultured pearls commercially since the 1990s and is expected to produce approximately 2,000 kg per annum (N. Sturman et al., “Vietnam: Shell nuclei, pearl hatcheries, and pearl farming,” Fall 2020 G&G, pp. 402–415), which is significantly smaller than Japan’s anticipated annual production of approximately 20 tons (roughly 18,000 kg) (T. Matsuyama et al., “Mass mortality of pearl oyster (Pinctada fucata (Gould)) in Japan in 2019 and 2020 is caused by an unidentified infectious agent,” PeerJ, Vol. 9, 2021, article no. 12180).

Figure 4. This set of ombré pearl strands, made up of round Tahitian pearls with silver and gold South Sea pearls ranging from 10 to 10.4 mm, is also known as shikisai, which means “colors of four seasons” in Japanese. Photo by Mimi Travis; courtesy of Yen’s Jewelry & Accessories Inc.

Figure 5. Mixed strand of 79 pearls ranging from 11.8 to 14.8 mm, consisting of pink Chinese freshwater, black Tahitian, golden Indonesian, and white Australian bead cultured pearls. Also pictured is an exceptionally large 20.4 mm South Sea bead cultured pearl, weighing 12 g. Photo by Robert Weldon; courtesy of Yoko London.
Eric Yen of Yen’s Jewelry & Accessories Inc. (San Francisco) and Alan Hakimian of Yoko London presented strands that combined multicolor pearls from different pearl types, offering variety and high fashion all at once (figures 4 and 5). Both pointed out that making mixed and graduated color strands is an efficient use of all the pearls produced from a harvest, just one example of economic sustainability in the pearl industry. Producing only perfectly matched color stands would lead to more waste.
Overall, pearl dealers are looking forward to the return of the gem, jewelry, and pearl shows in Hong Kong in 2023, as these are some of the largest shows for cultured pearls. Many have not been able to attend since 2019 due to lockdown restrictions in Hong Kong. @chapter:14


Publication Year: - Title: Emerald Quality Factors Abstract: This 5.30-carat emerald from Brazil has a slightly bluish green color. Courtesy John Parrish, courtesy African, Brazilian, Colombian Gems Incorporated.

                      Emerald has many special qualities, but colored stone professionals generally agree that emeralds are, most of all, about color. Emerald has been the standard for green among colored stones for thousands of years.

As with other colored stones, it requires a well-trained eye to recognize the sometimes subtle variations that make significant differences in emerald value. This is especially true in the higher qualities.

Color
The most desirable emerald colors are bluish green to pure green, with vivid color saturation and tone that’s not too dark. The most-prized emeralds are highly transparent. Their color is evenly distributed, with no eye-visible color zoning. If the hue is too yellowish or too bluish, the stone is not emerald, but a different variety of beryl, and its value drops accordingly.

The intensity of the green in the finest emeralds might not be equaled by anything else in nature.

Chromium, vanadium, and iron are the trace elements that cause emerald’s color. The presence or absence of each and their relative amounts determine the exact color of an emerald crystal.

Emerald appearance is sometimes associated with its mine location. Colombian emeralds are said to have a warmer and more intense pure green color. Zambian emeralds are said to have a cooler, more bluish green color. In spite of these theories, the truth is that emerald appearance overlaps between sources.

Clarity

	Emeralds that have no eye-visible inclusions are very rare. Tino Hammid, courtesy ICA.
Emeralds typically contain inclusions that are visible to the unaided eye. Because of this, trade members and some consumers understand and accept the presence of inclusions in emeralds. Eye-clean emeralds are especially valuable because they’re so rare.

Emerald inclusions are often described as looking mossy or garden-like. They’re sometimes called “jardin,” which is French for garden.

	This 10.03-carat stone is a trapiche emerald. Its inclusions form rays in a star-like pattern. This well-executed cabochon cut shows off this unusual arrangement. Courtesy Colombian Emeralds Co.
In colored stones, transparency and clarity are closely linked. This is especially true for emeralds. The trade generally accepts eye-visible inclusions in higher-quality emeralds. But when the inclusions have a negative effect on transparency and clarity, they also dramatically reduce value.

In early 2000, the GIA Laboratory began offering a classification service for emerald clarity treatments. The laboratory examines a loose stone and provides an Emerald Report that includes a digitally generated color image of the stone taken at the time it’s examined. The report describes the level of clarity enhancement as minor, moderate, or significant. The GIA Laboratory emphasizes that it uses the classification system only to evaluate the level of treatment, and not to offer an overall clarity grade for the stone.

Cut
The cutter must consider the rough’s depth of color, durability, and inclusions when making cutting decisions. Mistakes cause weight loss, which greatly reduces the value of a potentially valuable gem.

Four characteristics of emerald crystals make them difficult to cut. First, almost all emeralds have significant fractures (sometimes called fissures in the trade). A cutter must design the cut to minimize the effect of those fractures on the finished stone.

The second factor is due partly to those inherent fractures: Emeralds are more brittle than a gem like corundum. This makes them vulnerable to damage during cutting, polishing, and setting, or even during careless daily wear. The emerald cut can help protect against damage because the vulnerable corners are faceted and provide a comparatively safe place for prongs.

Third, because color is so important in establishing an emerald’s value, the cut must maximize the effect of hue, tone, and saturation. The cutter can affect color by adjusting an emerald’s proportions and number of facets. The cutter can darken a pale stone with a deep cut, a small table, and fewer facets, or lighten a dark stone with a shallow cut, a large table, and additional facets.

	As the name suggests, the emerald cut is the most common cut for emeralds. Courtesy Ronald Ringsrud Co.
Fourth, the bluish green to yellowish green dichroism of many emerald crystals encourages the cutter to orient the table so it’s perpendicular to the crystal’s length. That way, the more apparent color in the cut gem is the bluish green that so many emerald lovers prize.

Colombian rough is especially challenging due to the distribution of coloring agents during formation. Its color is more intense closer to the surface. Without careful planning and cutting, the finished stone might be much lighter in color than the original material.

Carat Weight
Fashioned emeralds come in a wide range of sizes. There are emeralds in museums and private collections that weigh hundreds of carats. At the other extreme are tiny emeralds that weigh fractions of a carat.

The Sandawana emerald mine in Zimbabwe is known for its tiny, yet vividly colored stones. Its emeralds are as small as 1 mm square, but they’re still intensely green. The mine’s cut stones average about 0.05 to 0.25 carat, and rarely weigh more than 1.50 carats. Popular jewelry sizes are usually somewhere in between.

	The emerald center stone of this necklace weighs 61 carats. Courtesy Ronald Lee Schultz.
The smallest sizes range from 1 mm to 5 mm, with weights from 0.02 to 0.50 carat, while 1 to 5 carat stones are popular as center stones.  Prestigious pieces of jewelry can include emeralds that weigh over 20 carats.

Quality-for-quality, the price of emerald can rise dramatically as the size increases. @chapter:8


Publication Year: 2013 Title: Imitation Larimar Abstract: Figure 1. This 3.91 ct ceramic imitation of Larimar (left) is shown with Larimar from the Dominican Republic. Photo by Lore Kiefert.

Pectolite is a mineral of the wollastonite group with the chemical formula NaCa2Si3O8(OH). It has an RI of 1.599–1.628, with a typical spot RI reading of about 1.60 and a specific gravity of 2.81. The light blue variety of this mineral, known by the trade name “Larimar,” has only been reported from the Dominican Republic (R.E. Woodruff and E. Fritsch, “Blue pectolite from the Dominican Republic,” Winter 1989 G&G, pp. 216–225; figure 1).
We recently acquired a 3.91 ct drop-shaped cabochon, purchased in India as a Larimar imitation, that consisted of a ceramic material (figure 1). According to the vendor, the material was manufactured in China. Close microscopic examination showed white gas bubbles and blue color concentration (figure 2).

Figure 2. Microscopic observation reveals dark blue color concentrations
and whitish gas bubbles. Photomicrograph by Lore Kiefert; magnified 40×.
The cabochon’s spot RI reading of 1.53 and SG of 1.87 were distinctly lower than the values for Larimar. Semi-quantitative EDXRF chemical analysis gave a composition of 95% Al2O3 and 4% SiO2, with traces of SO3, K2O, CaO, Sc2O3, Cr2O3, Fe2O3, and Ga2O3. In contrast, the average composition of pectolite consists of 54.23% SiO2, 33.74% CaO, 9.32% Na2O, and 2.71% H2O.
Although the imitation material does indeed resemble Larimar, standard gemological tests such as microscopy, RI, and SG should be sufficient to distinguish it. @chapter:13


Publication Year: - Title: Blue Nile Sale Surprises Analysts, Argyle Auctions ‘Best’ Colors Abstract: The Argyle Violet is a 2.83 carat polished oval shaped diamond, the largest violet diamond from Rio Tinto’s Argyle Diamond Mine. It is part of the Chroma Collection. Photo courtesy of Rio Tinto

	The deal that will see Blue Nile go to an investment group headed by Bain Capital Private Equity will likely mean big changes for the online diamond retailer. The company, whose double-digit growth had dazzled the U.S. retail jewelry industry in the previous decade, plateaued in recent years with sales hovering between $450 million and $480 million. Its net profits were about 2% of sales, running about $10 million yearly.

	The purchase price of $500 million paid by Bain and Bow Street LLC surprised some analysts. It was 30% over the share price and the small profit ratio, even with the company’s $109 million in assets, means it could take many years to recoup the investment without significant changes in the company’s business model.

	Engagement rings have been Blue Nile’s staple since its founding in 1999, representing between 60-75% of sales. In recent years, however, as the number of marriages in the U.S. stagnated, the company attempted to shift its focus to designer pieces and international sales. Its success in both areas has been limited. Neither Bain nor Bow Street indicated what changes may be in the offing, except to state they are “looking forward to working alongside Blue Nile management to execute the company’s strategy.”

	Blue Nile reported sales of $105.1 million for the third quarter of 2016, down nearly 5% from the comparable quarter last year. Net income was $1.3 million, or slightly over 1%. Diamond engagement ring sales declined 8.5% during the period to $59.5 million. International sales rose slightly in the quarter.

	The deal likely will close early next year. Bain Capital Private Equity is the venture capital arm of Bain Capital.

The Argyle Aria, a 1.09 ct oval shape Fancy red diamond, is part of the Chroma Collection. Photo courtesy of Rio Tinto

	ARGYLE FANCY COLOR SALE

	Rio Tinto is finding that deeper may be better as far as fancy colored diamonds from its Argyle Mine are concerned.

	This year’s offering of fancy colors comprised the highest size, color and clarity combination in the 32 years of auctioning such stones. All of the diamonds came from the new underground operation that began three years ago.

	The group, named the Chroma Collection, consists of 63 stones, weighing 58.24 carats total. It included 57 pinks, two violet and four red diamonds, all graded by GIA.

	The largest was the 2.83 carat (ct) Argyle Violet, the biggest violet diamond ever found at the mine. GIA graded the color Fancy Deep grayish bluish violet. The other violet diamond, the Argyle Ultra, was a 1.11 ct Fancy Dark gray-violet pear shape.

	Other highlights of the Chroma Collection include the Argyle Thea, a 2.24 ct Fancy Vivid purplish pink; the Argyle Viva, a 1.21 ct Fancy Vivid purple-pink; and the Argyle Aria, a 1.09 ct Fancy red.

	Rio Tinto said in a statement that this tender achieved record results, but it did not announce sale prices or the total realized for the collection. @chapter:30