Publication Year: 2023 Title: Grayish Blue CVD Diamond Colored by GR1 and SiV– Abstract: Figure 1. Left: This 1.63 ct grayish blue diamond was identified as a CVD synthetic, with its color caused by both the GR1 and SiV– centers. Photo by Xiaoyu Zhang. Right: Dark cloud-like non-diamond carbon inclusions. Photomicrograph by Meng Li; field of view 0.25 mm.
Silicon is a common impurity in chemical vapor deposition (CVD) laboratory-grown diamond. The silicon-related SiV– center, which has zero-phonon lines at 736.6 and 736.9 nm and is active in absorption and luminescence, is widely considered an identifying feature of CVD diamond. Generally, the SiV– center is detected by photoluminescence spectroscopy and is not observed using absorption spectroscopy for most CVD synthetics due to the low silicon content. The absorption spectra may reveal the presence of the SiV– center in the case of a relatively high silicon content, but rarely in amounts significant enough to affect the color. When the silicon content becomes particularly high, the absorption of SiV– is in sufficient concentration to influence the bodycolor of a diamond. It has been reported that the color of silicon-doped blue CVD diamonds produced by the PDC Company is attributed to strong absorption of the rather intense SiV– center (A. Peretti et al., “New generation of synthetic diamonds reaches the market (Part A): Identification of CVD-grown blue diamonds,” Contributions to Gemology, No. 14, 2013, pp. 3–20).

Figure 2. In the Vis-NIR region, in addition to very strong absorptions at 737 nm (SiV–) and 741 nm (GR1), weak absorptions at 830, 856, and 946 nm (SiV0) were observed.
National Gemstone Testing Center’s (NGTC) Beijing laboratory recently received a 1.63 ct grayish blue princess cut (figure 1, left) for identification. Standard testing identified it as a CVD synthetic diamond. The sample showed an even color distribution. Microscopic investigation revealed abundant non-diamond carbon inclusions in the form of both crystals and clouds, with the clouds distributed along the growth layer (figure 1, right). The visible/near-infrared (Vis-NIR) spectrum (figure 2), recorded at liquid nitrogen temperature, included a strong broad SiV– center defect at 737 nm next to an equally strong GR1 center. The diamond’s grayish blue bodycolor was attributed to both the strong GR1 center and the high intensity of the SiV– center, which produced preferential absorption in the red part of the spectrum. In addition, weak absorptions at 830, 856, and 946 nm (the SiV0 center) were observed, which were also reported in CVD synthetic diamonds with high silicon content (Peretti et al., 2013; Z. Song et al., “Silicon-doped CVD synthetic diamond with photochromic effect,” Journal of Gems and Gemmology, Vol. 18, No. 1, 2016, pp. 1–5).

Figure 3. DiamondView imaging showed green fluorescence with blue dislocations. The diamond also revealed a layered growth structure, indicating a start-stop cycling growth process typical of CVD diamond, as CVD diamond growth takes place layer by layer on the top surface of the growing crystal. Image by Xiaoyu Zhang.

Figure 4. The PL spectrum of the grayish blue CVD synthetic diamond obtained with 473 nm excitation (A) showed that the H3 center (503.2 nm) and radiation-related features included very strong 3H at 503.5 nm and weak 486.3 nm. B: 532 nm excitation revealed the NV centers and silicon-vacancy center that are typically observed in CVD-grown diamonds, along with strong GR1. C: 785 nm excitation showed the H2 center at 986 nm.
Infrared spectroscopy showed features typical for type IIa diamond (i.e., no defect-related absorptions were detected). The diamond was inert to short-wave and long-wave ultraviolet illumination. Under the ultra-short-wave UV radiation of the DiamondView, the sample fluoresced green, with minor areas showing some blue dislocations. It also showed subtle growth striations and two parallel planes fluorescing stronger than the bulk of the crystal (figure 3). The sample did not phosphoresce. Photoluminescence (PL) spectra taken with various laser excitation wavelengths and at liquid nitrogen temperature (figure 4) showed the presence of radiation-related features including very strong 3H at 503.5 nm, strong GR1 at 741 nm, and weak 486.3 nm. The PL spectra also indicated strong nitrogen-vacancy centers at 575 NV0 and 637 NV– nm and multi-nitrogen defects such as H3 and H2, combined with the absence of the unassigned 596/597 nm doublet that is normally seen in as-grown CVD synthetics, suggesting that it had undergone post-growth high-temperature annealing before irradiation.
The PL spectrum with 532 nm laser excitation also exhibited a rather large silicon doublet peak at 736.6/736.9 nm that dwarfs all other PL peaks, including the GR1 in the spectrum. The intensity ratio between the 736.6/736.9 nm PL peak and the diamond Raman peak was about 52. The PL spectrum reaffirmed that the 737 nm absorption peak of the ultraviolet/visible spectrum was the SiV– defect, and the silicon content of this diamond was so high that it produced strong absorption in the red range of visible light and affected the color of the diamond together with the GR1 center. @chapter:15


Publication Year: 2018 Title: Two Natural “Horse Conch” Pearls Abstract: Figure 1. Two natural “horse conch” pearls and the shell from which they were reportedly extracted. Photo by Johnny Leung.

GIA’s Hong Kong laboratory recently examined two strongly saturated reddish orange non-nacreous pearls weighing 126.20 ct and 4.89 ct, and measuring 40.80 × 23.70 × 20.96 mm and 10.53 × 8.55 × 7.68 mm, respectively. The client who submitted the pearls also provided the shell from which they were reportedly extracted (figure 1). While such information must be treated with a degree of caution, our client also stated that the shell and pearls were handed to him by a fisherman who claimed to have found them in the waters off Isla Mujeres, near Cancun, Mexico. The shell measured approximately 47 × 24 × 24 cm and appeared pinkish orange with an orangy brown periostracum. Its large size, characteristic shape, pinkish orange color, and fine slender flame structures enabled us to identify it as a member of the Triplofusus genus, most likely Triplofusus papillosus or Triplofusus giganteus, sometimes referred to as Pleuroploca gigantea (E. Strack, Pearls, Rühle-Diebener-Verlag GmbH & Co., Stuttgart, Germany, 2006, p. 108; Fall 1994 Lab Notes, p. 195). These are all names that have been used to describe the Florida horse conch, though differences of opinion on the correct nomenclature applicable exist (D.P. Berschauer, “What’s in a name – the Florida horse conch,” The Festivus, Vol. 49, 2017, pp. 110–116). The Triplofusus genus is part of the Fasciolariidae subfamily which is a very diverse group of marine gastropods. The parallel line patterned Pleuroploca trapezium is another member of the Fasciolariidae subfamily said to produce unusual horse conch pearls (H. Bari and D. Lam, Pearls, Skira Editore S.p.A, Milan, 2009, pp. 70–73).

Figure 2. Short spiky flame structure on the 4.89 ct pearl (left, field of view 3.74 mm), and fine, elongated flame structure on the 126.20 ct pearl (right, field of view 2.83 mm). Photos by Sharon Tsz Huen Wu.
The larger of the two pearls displayed an uneven coloration with some lighter areas blending into a more saturated reddish orange. The smaller pearl was more homogeneous in appearance. The flame structures appeared spiky on the smaller pearl but were fine and elongated on the larger pearl (figure 2). Real-time microradiography revealed small void-like features in the center of the smaller pearl and toward the tapered end of the larger pearl. Such voids are not uncommon in the pearls of a number of porcelaneous pearl-producing mollusks. GIA has recorded similar features in examples from species of Tridacna/Hippopus, Strombus gigas, Cassis, and Melo. While the flame structures bore some similarities to those seen in Strombus gigas (conch) pearls, their strong reddish orange color and internal structures aligned more closely with horse conch pearls. Raman spectroscopy using 514 nm laser excitation detected aragonite peaks at 702, 706, and 1086 cm–1, as well as peaks at 1130 and 1520 cm–1 attributed to naturally occurring polyenic pigments responsible for the strong reddish orange color. The natural coloration was further supported by the presence of numerous polyenic-related peaks in the PL spectrum (figure 3) collected with the same laser excitation.

Figure 3. The PL spectrum of the 4.89 ct horse conch pearl displayed numerous peaks associated with naturally occurring polyenic pigments.
Although GIA handles a wide range of pearls originating from different mollusk species, horse conch pearls are among the rarest examined. It was, therefore, very rewarding to handle the 126.20 ct pearl and its smaller partner together with the shell from which they reportedly originated. @chapter:14


Publication Year: 2023 Title: Starry Night in Diamond Abstract: Figure 1. Rare cloud inclusions were observed in a 0.53 ct D-color diamond. Photomicrograph by Nathan Renfro; field of view 2.39 mm.
In astronomy, a star cloud is defined as a group of many stars. A diamond recently submitted to GIA’s Surat lab contained cloud inclusions resembling a starry night (figure 1). This diamond was a 0.53 ct D-color natural round brilliant with SI2 clarity. Fourier-transform infrared absorption spectroscopy indicated a type IaAB diamond with low nitrogen content of about 5 ppm. Each of the cloud inclusions had apparently randomly placed dendrites. The star field in this stone appeared comparable to a diamond described previously (Fall 2017 G&G Micro-World, p. 369); however, the individual clouds in that diamond resembled crosses of uniform orientation that corresponded with the cube face.

Figure 2. This deep ultraviolet fluorescence DiamondView image shows that the cloud inclusion features appear to be contained within a single growth zone. Image by Sally Eaton-Magaña.
Photoluminescence (PL) mapping using 455, 532, and 633 nm excitations was used to determine whether optical features could be detected within the cloud inclusions, as that analysis method has proven useful with cloud features in other diamonds (Fall 2020 Lab Notes, pp. 416–419). However, the PL maps were inconclusive, as no distinctive features were detected within the star-shaped inclusions. In deep ultraviolet fluorescence imaging, they appeared to be contained within the same growth zone (figure 2).
The inclusion suite was an interesting collection of cloud formations and a delightful discovery in this unusual diamond. @chapter:11


Publication Year: - Title: Hurricanes Harvey, Irma May Wreak Havoc on Luxury Sales, Too Abstract: The impact of Hurricanes Harvey and Irma are likely to be felt during this year’s holiday jewelry sales. Above, an Aug. 28 aerial view shows the damage caused by Hurricane Harvey in Rockport, Texas, located on the coast, southwest of Houston. Photo by AMFPhotography/Shutterstock.com

De Beers announced that it will spend $140 million on diamond advertising this year. Some of these funds will go toward the Diamond Producers Association generic diamond jewelry advertising, but the majority will go to its ForeverMark brand.

Advertising may not help lift U.S. demand this coming fall season because of the devastating damage of Hurricane Harvey in eastern Texas and Hurricane Irma in Florida, particularly in the affluent western coast areas. The damage and disruption of both hurricanes will likely take a toll on luxury sales.

Texas, particularly the Houston area, has always been a center for luxury sales, including larger diamonds and significant jewelry pieces. Many of the jewelers serving that area escaped the worst of the flooding from Harvey, but a significant portion of their clientele will likely face huge rebuilding and repair costs.

Although Hurricane Irma spared the Miami area the worst of its effects, wind damage was still immense and many communities were totally destroyed throughout the state. Obviously, there will not be a full damage assessment of either Texas or Florida for months, but it’s certain these two hurricanes will be the most extensive and expensive disasters ever to hit the U.S.

While the storms may initially impact jewelry sales in these regions, jewelers have noted that after similar destructive storms, a boom in rebuilding ultimately brought more money back to the region.
DIAMONDS
De Beers’ August-September cycle (sight) totaled $505 million, a reduction of 21% from last year’s sale for that period and 12% down from the July cycle. The reasons, according to De Beers’ CEO Bruce Cleaver, were two-fold:

De Beers front-loaded goods to Indian clients in anticipation of an early Diwali holiday, which begins Oct. 18, one or two weeks earlier than usual.
Prevailing caution in the market in the run-up to the Sept. 13-21 Hong Kong shows.

On the first point, Indian diamond manufacturers typically close for two weeks during the holiday. If the market is slow, they will often stay closed for a longer period to let inventories subside and to bolster polished prices.

On the second point, rough sales and manufacturing have been running ahead of polished demand for most of the year in most size and quality categories. While there are spot shortages of very specific goods (medium-color melee sized SI stones, for example), in general there is an oversupply of inventory that is softening polished prices. Estimates are that inventories have increased 25% to 35% in the past 18 months, without a corresponding increase in demand.

Additionally, the diamond industry credit crunch continues to squeeze a lot of firms – even some big names – and softening processes do not help their case with the banks. As with the previous few years, the opening of the Hong Kong show will bring a dash for cash, with a lot of firms selling excess goods at a discount to keep their standing with the banks.

Regardless of the inventory situation, demand for rough has remained robust all year – as it has since the late 2015 “price rebellion,” when a number of De Beers’ clients refused to buy goods at then-current prices. De Beers, followed by Alrosa and Rio Tinto, lowered prices by an average of 15% early in 2016. Prices of polished stones, however, have slowly ebbed this year.
CHINA
Retail sales in China have taken an encouraging upturn. Chow Sang Sang, the country’s second largest jewelry retailer, logged a 3% same-store increase for the first half ending June 30. Sales in the mainland rose 8%, but continued slow tourism in Hong Kong and Macau caused declines of 4% and 5%, respectively. @chapter:27


Publication Year: - Title: Spring 2017 G&G: Brazil’s Diamond Production, Cuprian Liddicoatite, Silicon in Corundum, and Tucson Coverage Abstract: The lead article of this issue covers Brazilian diamond production, which reached its peak in the late 1700s. Our cover shows a brooch dating back to the mid-19th century. This piece contains a 0.77 ct natural Fancy Light pink antique pear-shaped diamond set in darkly patinated silver ribbons over gold. The total weight of the diamonds exceeds 5.20 carats. Photo by Robert Weldon/GIA, courtesy of Lang Antique & Estate Jewelry.

	From Brazilian diamonds and Japanese jadeite to Indian iridescent quartz and Polish by-product zincite, a world of wide-ranging topics is covered in the Spring 2017 issue of Gems & Gemology. The issue looks at historical and unexpected sources of gemstones, plus surprising discoveries revealed through advanced chemical analyses. News and updates from the annual Tucson gem shows and our multiple-choice Challenge quiz are also included in the Spring issue.

	BRAZILIAN DIAMONDS: A HISTORICAL AND RECENT PERSPECTIVE

	The Portuguese Placa dos Três Militares, or Badge of the Three Military Orders, was
	made in 1789, and is now part of the crown jewelry collection of the Ajuda National
	Palace in Lisbon. The badge consists of Brazilian diamonds as well as emeralds and
	rubies, and it is designed in a way to conceal the metal mounting and emphasize the
	gems. Photo by Manuel Silveira Ramos, courtesy of the Ajuda National Palace.

	Brazil is known for its wealth of colored stones, but it was at one time the world’s leading diamond producer. For three centuries Brazil has supplied a steady, if relatively small, supply of diamonds to the world market. It is also a source of superdeep and fancy-color diamonds and carbonado. In Brazil, diamonds are gathered from alluvial deposits (primarily in Mato Grosso and Minas Gerais), while primary sources remain unknown. Authors Darcy Svisero, James Shigley, and Robert Weldon look at Brazil’s centuries-old diamond production with historical perspective, geological insight, and expectations for future mining.

	COPPER-BEARING LIDDICOATITE TOURMALINE

	Six of the 13 cuprian liddicoatite tourmalines from this study. The faceted stones weigh 1.59–9.63 ct (average 3.95 ct). They are transparent and have greenish blue, green-blue, and green colors. Photos by Masumi Saito.

	Copper-bearing (Paraíba) tourmaline is usually classified as part of the elbaite species. Recently, 13 cuprian tourmalines submitted to GIA’s Tokyo lab were analyzed with LA-ICP-MS for origin determination. While the origin of the stones remains unknown, Yusuke Katsurada and Ziyin Sun discuss the surprising results that led them to classify the samples as liddicoatite, rather than elbaite.

	THE ROLE OF SILICON IN THE COLOR OF GEM CORUNDUM

	Paula Crevoshay’s “Yogo Columbine” pendant displays the remarkably consistent blue color of Yogo sapphires: 243 in all, with a total weight of 13.89 carats. The piece also contains 0.59 ct of yellow sapphires and 1.37 ct of diamonds, set in 18K yellow and white gold. Photo by Orasa Weldon.

	The chemical interactions of silicon, titanium, and magnesium are known to influence the color of gem-quality corundum, but until recently the role of silicon has not been fully understood. John Emmett, Jennifer Stone-Sundberg, Yunbin Guan, and Ziyin Sun explore how ion implant standards and the application of SIMS has led to accurate measurement of silicon in corundum for the first time. This measurement makes clear the important role of silicon in corundum color; the blue of Yogo sapphire from Montana is used to illustrate this discovery.

	JAPANESE JADEITE: HISTORY, CHARACTERISTICS, AND COMPARISON WITH OTHER SOURCES

	A large, attractive jadeite boulder from Itoigawa, Japan, characterized by mixed white
	and green colors. This boulder weighs 40.5 kg and measures approximately 39 cm
	high, 32 cm long, and 26 cm wide. Photo by Ahmadjan Abduriyim.

	Gem-quality jadeite jade has been known from Japan for millennia. In this article, Ahmadjan Abduriyim, Kazuko Saruwatari, and Yusuke Katsurada examine the historical context, chemical composition, and color of Japanese jadeite. They also compare characteristics of samples from the Itoigawa, Omi, and Wakasa regions to jadeite from Burmese, Guatemalan, and Russian deposits.

	CAUSES OF IRIDESCENCE IN NATURAL QUARTZ

	Iridescence is clearly visible on the minor z face of this iris quartz from Jalgaon, India.
	Photomicrograph by Peter J. Heaney; field of view 4.5 mm.

	The phenomenon of iridescence in gemstones is caused by either thin films or repetitive substructures. In an exploration of iris quartz specimens from Jalgaon District, India, Xiayang Lin and Peter Heaney discover a ridge and valley structure, produced by differential etching on the material’s minor z face, which produces its iridescent effect.

	CHARACTERISTICS OF GEM-QUALITY BY-PRODUCT SYNTHETIC ZINCITE

	Most of the by-product synthetic zincites in this study had a reddish orange to yellow color; one sample (ZnO-G) was yellowish green. Top row, left to right: samples ZnO-LC (69.23 ct) and ZnO-SC (31.71 ct). Bottom row, left to right: samples ZnO-G (0.32 ct) and zin-7 (5.61 ct). Composite photo by Ji Zhang.

	Synthetic zincite has been found in industrial kilns in Poland as a by-product of zinc oxide powder production. This accidental zincite has better transparency and brighter color than its natural counterpart. Ji Zhang, Yujie Gao, and Guanghai Shi examine samples of by-product synthetic zincite from a Polish foundry to establish their distinguishing characteristics, identify their inclusions, and find their cause of color.

	LAB NOTES

	This 0.42 ct green HPHT synthetic diamond displayed strong growth sectors that were observed without magnification. Photo by Jian Xin (Jae) Liao.

	GIA’s gemologists report on notable lab submissions, including a surprising source of green color in HPHT synthetic diamond, a Paraíba tourmaline with an unusual submetallic coating, and a cape diamond showing yellow phosphorescence.

	MICRO-WORLD

	In this scene, pyrite inclusions have dissolved, leaving behind hematite and goethite, both of which react dramatically to polarized light. Photomicrograph by John Koivula; field of view 10 mm.

	The inner world of gemstones continues to captivate, and the Spring 2017 section features sapphires showing negative crystals, flame-like structures in precious opal from Ethiopia, and a mysterious inclusion combination in Sri Lankan topaz.

	GEM NEWS INTERNATIONAL

	A 28.21 ct freeform Oregon sunstone from the Dust Devil mine is the centerpiece of this ring. Photo courtesy of Sonja Kreis Unique Jewelry.

	The GNI section contains G&G’s annual coverage of the Tucson gem shows. Highlights include emeralds from a new deposit in Ethiopia and a Burmese gem update following the lifting of U.S. sanctions on Myanmar. Other entries report on the chemical composition of color-change pyrope-spessartine garnet, and a calcite sphere exhibiting strong phosphorescence.

	The Spring issue also contains the 2017 Gems & Gemology Challenge. Score 75% or better and you’ll receive a certificate of completion (PDF file); earn a perfect score and your name will be listed in the Fall 2017 issue. Mail-in cards and online entries for the Challenge must be submitted by Friday, August 11, 2017. @chapter:18


Publication Year: 2013 Title: Calcium Fluoride Coating Found on 13 "Fancy" Pink Diamonds Abstract: Figure 1. These face-up images of 0.5 ct and 0.45 ct pink round brilliants are representative of the 13 coated pink diamonds submitted. Photo by Jian Xin (Jae) Liao.

Coating gemstones to alter or improve their color is the oldest known enhancement method. Early coatings, particularly on diamond, were easily detected, often visible using a 10× loupe. But advances made after World War II resulted in more durable coatings and films that were subtler and harder to detect.
A common coating was calcium fluoride (CaF2) doped with gold (Au) nanoparticles. CaF2 causes a broad absorption band at about 520 nm, similar to the band at about 550 nm that largely accounts for the pink color of natural diamonds.
Recently submitted to the East Coast laboratory for identification and grading was a group of 13 pink diamonds. The round brilliants ranged from 0.42 to 0.50 ct and had a Fancy pink to Fancy Intense pink color. The above photo shows the patchy appearance characteristic of coated diamonds. Microscopic examination using reflected light revealed obvious coating on the pavilion facets, with patchy colorless areas where it had been removed (figure 2).

Figure 2. Photomicrographs of the pink diamonds from figure 1, taken with reflected light at 80× and 100× magnification, reveal the coating applied to the pavilion facets. Photomicrographs by Paul Johnson.
The UV-visible spectra of all 13 diamonds exhibited a broad band centered at about 520 nm, not at 550 nm as expected. This band is responsible for the pink coloration, and the 520 nm position identified the coating as fluoride.

This example demonstrates that traditional treatments such as coating are still prevalent in the trade, and great care must be taken to identify them. Because coatings are not permanent, all 13 diamonds were issued identification reports disclosing the treatment. @chapter:35


Publication Year: 2015 Title: Amethyst From Morocco:An Update Abstract: Figure 1. These Moroccan amethyst crystals, which weigh 2.87 and 6.24 grams, display an attractive purple zoning conforming to the rhombohedral faces. Photo by Nuttaphol Kitdee.

Most major sources of fine amethyst are located in Africa. Yet African amethysts on the market, especially Zambian material, tend to be dark and difficult to find in sizes larger than 10 ct. Since the late 1980s, there have been additional discoveries in Malawi, Tanzania, Namibia, Nigeria, and the Democratic Republic of Congo. The most recent African source is Morocco (see Spring 2009 GNI, pp. 62–63), which has produced gem-quality amethyst with an appealing purple color and sizes larger than 10 ct.

GIA’s Bangkok laboratory recently examined several parcels of gem-quality Moroccan amethyst (figure 1) received from Tom Banker, a colored stone dealer. Gemological properties obtained from the crystals and faceted stones were similar to those reported in the 2009 GNI entry.

Figure 2. A closer view of the amethyst shows alternating bands of darker and lighter purple color zoning. Photo by Charuwan Khowpong; magnified 10×.
Common characteristic internal features were intense color zoning conforming to the rhombohedral faces (figure 2), reddish brown needle-like hematite inclusions (figure 3, left), and fingerprints consisting of two- and three-phase inclusions (figure 3, center). Dolomite and anhydrite inclusions were also found (figure 3, right).

Figure 3. Microscopic examination of the Moroccan amethyst samples revealed reddish brown hematite (left), two-phase inclusions (center), and dolomite crystals (right). Photomicrographs by Charuwan Khowpong; magnified 50×, 5×, and 80×.
A thin wafer with a thickness of 1.28 mm was prepared for FTIR and UV-Vis-NIR spectroscopy. The wafer plane was oriented parallel to the c-axis. The FTIR spectra were recorded using a Thermo Nicolet 6700 spectrometer with a resolution of 4 cm–1 and 200 scans, while the UV-Vis spectra were collected using a Hitachi U-2910 spectrometer at 1.5 nm slit width and 100 nm/min scan speed, integrated with a polarizer accessory controlled by Thorlabs APT.

FTIR spectroscopy revealed typical features of amethyst. The absorption peaks at 3585 and 3613 cm–1 were related to vibrations caused by Al substitutions. The absorption shoulder at 3595 cm–1 is common in natural quartz and rarely seen in synthetic quartz. The cause of this feature remains unknown (S. Karampelas et al., “Infrared spectroscopy of natural vs. synthetic amethyst: An update,” Fall 2011 G&G, pp. 196–201). Areas of dark, medium, and light purple zoning had very similar FTIR patterns.

Amethyst owes its purple color to color centers associated with Fe2+ or Fe3+ impurities (A.J. Cohen, “New data on the cause of smoky and amethystine color in quartz,” The Mineralogical Record, Vol. 20, No. 5, 1989, pp. 365–367). The UV-Vis-NIR absorption spectra showed bands in the visible range at 545 nm caused by Fe4+ charge transfer (E.H.M. Nunes, “Spectroscopic study of natural quartz samples,” Radiation Physics and Chemistry, Vol. 90, 2013, pp. 79–86; E. Neumann, “Mechanism of thermal conversion of color and color centers by heat treatment of amethyst,” Neues Jahrbuch für Mineralogie, Monatshefte, 1984, No. 6, pp. 272–282). The complexity of absorption bands in the ultraviolet region is related to the presence of Fe3+ in more than one environment in the α-quartz structure (F. Hassan and A.J. Cohen, “Biaxial color centers in amethyst quartz,” American Mineralogist, Vol. 59, Nos. 7–8, 1974, pp. 709–718).

Further chemical analysis using advanced techniques such as EDXRF and ICP-MS will be conducted to summarize the characteristic chemical profile of the Moroccan material. @chapter:5


Publication Year: 2022 Title: Synthetic Sapphire with Rose Channels Abstract: Figure 1. A 15.84 ct light purplish blue synthetic sapphire measuring 15.35 × 14.05 × 8.25 mm. Photo by U. Hennebois.
The Laboratoire Français de Gemmologie (LFG) received a 15.84 ct light purplish blue corundum for identification (figure 1). Under the microscope, clouds of bubbles similar to those seen in synthetic corundum were observed (figure 2), along with twinning planes and hollow channels known as Rose channels (figures 2 and 3). The Rose channels, which are always found at the intersection of twin lamellae, were crystallographically oriented along the edges of the rhombohedral faces and formed angles of about 90° (again, see figure 2); these features are normally seen in natural corundum (F. Notari et al., “‘Boehmite needles’ in corundum are Rose channels,” Fall 2018 G&G, p. 257).

Figure 2. Clouds of bubbles, Rose channels, and twinning planes in the synthetic corundum under crossed polarizers. Photomicrograph by U. Hennebois; field of view 3 mm.

Figure 3. Clouds of bubbles, Rose channels, and twinning planes in the synthetic corundum. Photomicrograph by U. Hennebois; field of view 10 mm.
Rose channels and twinning lamellae are common in natural corundum but seldom reported in synthetic corundum, including one instance in a Ramaura flux synthetic ruby (E. Fritsch et al., “Are boehmite needles in corundum Rose channels?” Geophysical Research Abstracts, Vol. 20, EGU2018-19493, 2018). This is because the twinning lamellae is most often formed via deformation twinning and results from post-growth events; thus, it is frequently observed in natural samples.

Figure 4. DiamondView imaging revealed curved growth lines characteristic of synthetic Verneuil corundum. Image by A. Herreweghe; field of view 10 mm.
The sample was inert under long-wave UV and presented strong blue luminescence under short-wave UV. No gallium was detected with energy dispersive X-ray fluorescence, which further confirms that this corundum was synthetic (S. Muhlmeister et al., “Separating natural and synthetic rubies on the basis of trace-element chemistry,” Summer 1998 G&G, pp. 80–101). DiamondView imaging showed curved growth lines, characteristic of Verneuil flame-fusion synthetic corundum (figure 4). Rose channels in corundum were linked in the past with boehmite needles and the characteristic absorptions in the 1500–4000 cm–1 region (Notari et al., 2018); however, no absorptions were observed in this region of the FTIR spectrum.
Although by far most common in natural corundum, the presence of Rose channels and twinning planes in synthetic corundum serves as evidence that these features alone cannot be used to confirm natural origin. @chapter:12


Publication Year: 1998 Title: Fingerprinting of Two Diamonds Cut from the Same Rough Abstract: If it can be determined that two faceted diamonds came from the same piece of rough, romantic value is added to the stones. X-ray topography and cathodoluminescence (CL) tomography were used to prove that a round brilliant and a pear-shaped brilliant were cut from the same piece of rough. With these techniques, the internal imperfections and inhomogeneities that reflect the distinctive growth history of the original diamond crystal can be seen. X-ray topography is a powerful tool for imaging the distribution of lattice defects; CL tomography is more sensitive for detecting faint chemical inhomogeneities. By combining the two methods, the sophisticated gemologist can view both physical and chemical characteristics of a crystal, and thus its growth history, and use this information to fingerprint a given stone. @chapter:31


Publication Year: - Title: Jade Care and Cleaning Guide Abstract: Jadeite is 6.5 to 7, and nephrite is 6 to 6.5 on the Mohs hardness scale.

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

Jadeite is 6.5 to 7 and nephrite is 6 to 6.5 on the Mohs hardness scale, so some care should be taken to avoid scratches. However, both of these gemstones have exceptional toughness and are very resistant to breaking or chipping.

Stability
Heat from a jeweler’s torch can harm jade. Jade is stable to light, and it can be affected by warm acids.

Cleaning
Ultrasonic cleaners and steam cleaners are safe for untreated jade. But jade might be treated by dyeing, bleaching and impregnation, coatings, or heat treatment, so warm, soapy water is always a safe choice. @chapter:37


Publication Year: 2019 Title: Uvarovite in Prehnite from Pangasinan Province, Philippines Abstract: This new ornamental gem material from the Philippines consists of vibrant green uvarovite garnets in a white prehnite matrix. The polished freeform weighs 4.23 ct. Photo by Robison McMurtry.

Uvarovite, Ca3Cr2(SiO4)3, is the rarest of the commonly encountered garnet species, and the only one that is consistently green. Although seldom faceted due to its tendency to be opaque, drusy coatings of tiny bright green uvarovite crystals on chromite matrix from Russia are used for jewelry. Recently, a new type of rock with lapidary potential was reportedly discovered in the Philippines, consisting of a white prehnite matrix with vibrant green crystals of uvarovite (see above).
This new material was brought to the authors’ attention by Xavier A. Cortez, who operates Crystal Age, a gem shop in Quezon City. While attempting to source jade for his shop in early 2019, Xavier was offered unidentified white stones speckled with bright green crystals from local miners on the island of Luzon. Mr. Cortez was able to track down the source of this material to a rural portion of Pangasinan Province, in the Ilocos region of Luzon. Weathered calc-silicate rocks at this deposit yield small euhedral crystals of opaque bright green garnets as well as compact green masses in white matrix. The measured spot refractive index of 1.63 was consistent with prehnite. The identities of the green uvarovite and the white prehnite matrix were confirmed with Raman spectrometry.
While there is currently very little of this material on the market, it could be used as a jadeite simulant due to its mottled white and green appearance. Aside from its potential as a jadeite simulant, it is an interesting ornamental material that can be appreciated for its own unique beauty and vibrant green color. @chapter:5


Publication Year: 2020 Title: Inclusions in Kenyan Rubies from the John Saul Mine Abstract: Figure 1. Bands of dense clouds of particles associated with iridescent short needles. Photomicrograph by Suwasan Wongchacree; field of view 1.75 mm.

Rubies from the John Saul mine have been available in the market since the 1970s. The gems are found in a pegmatite-like vein that intrudes an ultrabasic body within the country rock (Winter 1999 Gem News, pp. 213–215). While the mine has produced a large quantity of ruby with fine color, only a small part of the production is fine quality and suitable for faceting, with most of the samples being cut into cabochons. Production has declined, and the material is seen less nowadays.

Figure 2. A negative crystal surrounded by iridescent thin films. Photomicrograph by Charuwan Khowpong; field of view 1.20 mm.
The rubies have an inclusion scene that typically includes short, iridescent needles associated with dense clouds of particles, often in bands (figure 1). Negative crystals surrounded by a plane of thin films are also typical (figure 2). These are very similar to the inclusion scenes in rubies from Mogok (Myanmar) and other marble-hosted deposits. The fact that the color and fluorescence, which is dictated by the trace element chemistry, are also similar to marble-related deposits makes separating them from Kenyan rubies even more challenging. This shows that similar inclusion scenes can form in very different geological environments and that the internal world of gemstones is not always a conclusive indicator of geographic origin. @chapter:3


Publication Year: 2022 Title: Nail-Head Spicule in a Russian Emerald Abstract: Figure 1. A 1.86 ct transparent green pear mixed-cut emerald. Photo by Diego Sanchez.
Recently, a 1.86 ct transparent green pear mixed cut (figure 1) was submitted for identification to the Carlsbad laboratory. Initial testing produced the following results: refractive index values of 1.582–1.590, birefringence of 0.008, doubly refractive, and a hydrostatic specific gravity of 2.73. The long-wave UV reaction was red with a blue fluorescence in surface-reaching fractures from the clarity enhancement. These results were consistent with natural emerald. Trace element chemistry of the host emerald collected via laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) matched well with GIA’s Russian emerald chemistry reference data.

Figure 2. Nail-head spicule in the natural emerald from figure 1. Photomicrograph by Nathan Renfro; field of view 2.01 mm.
While the identification of any gem requires further testing with a variety of instruments, in most cases the stone’s natural or synthetic origin can be determined conclusively by features seen under magnification. Nail-head spicules are typically associated with synthetic hydrothermal (and occasionally flux-grown) emerald and synthetic quartz, but they are also occasionally found in natural gems such as beryl, sapphire, spinel, tourmaline, and quartz (G. Choudhary and C. Golecha, “A study of nail-head spicule inclusions in natural gemstones,” Fall 2007 G&G, pp. 228–235; K. Schmetzer et al., “Multicomponent inclusions in Nacken synthetic emeralds,” Journal of Gemmology, Vol. 26, No. 8, 1999, pp. 487–500). Nail-head spicules are wedge-shaped two-phase (liquid and gas) inclusions capped by crystals that act as growth obstacles (figure 2). During growth of the host crystal, a small crystal or platelet is deposited on its surface. As the crystal continues to grow past the inclusion, a tapered void is created, which traps the hydrothermal growth medium such that, upon cooling, it becomes two phases consisting of liquid and a gas bubble (Choudhary and Golecha, 2007). @chapter:9


Publication Year: 2013 Title: Unusual Curved Color Zoning In Emerald Abstract: While curved color zoning is typically associated with melt-grown synthetics, particularly flame-fusion products such as synthetic corundum and synthetic spinel, an unusual natural emerald with this feature was recently examined in the Carlsbad and Bangkok laboratories. This 1.17 ct emerald was obtained for GIA’s permanent reference collection (sample number 100305160993) at a street market in Kabul, Afghanistan, for its very unusual inclusion scene. The stone was represented as being of Afghan (Panjsher) origin, but the internal inclusions seemed to resemble those of emeralds collected from the Swat Valley of Pakistan. Careful chemical analysis by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) was performed at the GIA lab in Bangkok. The chemical data showed a fairly even composition within the sample except for chromium, which varied proportionately with the green color zoning (from approximately 300 to 9000 ppmw Cr). The chemical data of the unusual emerald were compared to those of reference standards from known deposits, particularly Panjsher and the Swat Valley, to investigate its probable origin. The data showed a close match only with the reference emeralds from the Swat Valley, making that the most likely origin.

Figure 1. This 1.17 ct emerald, which hosted pyrite and carbonate crystals, displayed unusual curved zoning. Photo by Sasithorn Engniwat.
The gemological properties showed an RI of 1.589–1.597 and a visible spectrum consistent with emerald. The stone showed no reaction to a standard 4-watt gemological UV light source. Microscopic examination revealed numerous inclusions of pyrite, carbonates, and reflective thin films oriented perpendicular to the optic axis (parallel to the length of the stone), a typical assemblage of a natural emerald. The most unusual observation about this stone was a prominent green “S” shape color zone that ran down its length (figure 1). Emerald’s hexagonal structure would ordinarily lead one to expect planar or angular color zoning related to the crystal morphology. The presence of curving zones in a faceted emerald was an anomaly that needed further examination.

Figure 2. Arrays of tabular offset pyrite fragments were seen throughout this unusual emerald. Field of view: 0.86 mm. Photomicrograph by Nathan Renfro.
One possible explanation for the unusual zoning is that compressional geological forces caused shearing along the emerald crystal’s basal plane. This was supported by the appearance of pyrite grains, which looked as if single, brittle pyrite crystals had been sheared and slightly displaced parallel to the basal plane of the beryl host (figure 2). This apparent lateral shearing movement throughout the emerald crystal could have caused the pyrite grains to separate into aligned tabular fragments offset from each other and the beryl host. Also observed between the pyrite grains were planar optical irregularities. These planes suggested localized shear zones that would have significantly higher defect concentration, giving rise to the optical nonconformity consistent with their location between the tabular pyrite inclusions. Under cross-polarized illumination, we observed dense clusters of birefringent crystals that were essentially invisible under non-polarized lighting. The low relief of these dense inclusions suggested they were beryl inclusions within the beryl host, possibly a result of partial recrystallization caused by dynamic environmental conditions.
Gemology is generally a non-destructive, observational science, which can be limiting at times. Destructive techniques could have revealed the crystallographic orientation of the pyrite grains with respect to each other and explained the stone’s unusual structure. Because this was a unique sample, destructive testing was not a practical approach. While the exact cause of this unusual zoning remains unknown, it is certainly interesting and thought provoking.The discovery of such gems demonstrates that there are complex geological conditions we do not yet understand which, when observed, invite further gemological exploration. @chapter:6


Publication Year: 1988 Title: The Diamond Deposits of Kalimantan, Borneo Abstract: The island of Borneo is one of the oldest known —and least reported on—sources of diamonds. Although diamond mining historically was concentrated in the western area of what is now Kalimantan, recent activity has focused on the alluvial deposits in the southeast. A progress report on the first bulk sample pit in this area found that significant amounts of diamonds appear to be concentrated beneath the center of the Danau Seran swamp. The traditional hand-mining methods contrast greatly with the sophisticated techniques used to mine the first bulk sample pit. Virtually all of the diamonds recovered are gem quality, although most are relatively small, averaging about 0.30 ct. Future potential for southeastern Kalimantan appears excellent. @chapter:20


Publication Year: 2019 Title: Low-Fe, High-V Color-Change Burmese Sapphire Abstract: Figure 1. This 5.68 ct cushion mixed-cut sapphire showed a strong color change from grayish violet in fluorescent light to purple-pink in incandescent light. Photo by Robison McMurtry.
A color-change sapphire was recently submitted to the GIA lab in Carlsbad for an origin determination report. The 5.68 ct transparent cushion mixed cut displayed a strong color change from grayish violet in fluorescent light to purple-pink in incandescent light (figure 1). Color-change sapphires generally range from blue to violet in daylight-equivalent (fluorescent) light and from purplish pink to pinkish purple in incandescent light. Stones displaying a strong color-change phenomenon are highly desirable.

Figure 2. A: Exsolved rutile as reflective platelets, arrowheads, particles, and needles in sapphire; field of view 6.42 mm. B: Loose white particle clouds arranged in a geometric pattern and in stacked planes; field of view 3.80 mm. C: Twinning lamellae are commonly observed in Burmese sapphires; field of view 4.79 mm. D: Boehmite needles or tubules often occur with polysynthetic twinning; field of view 4.79 mm. E: Reflective fingerprints with iridescence in sapphire; field of view 1.37 mm. Photomicrographs by Jonathan Muyal.
Standard gemological testing proved that this stone was corundum with a refractive index (RI) of 1.760 to 1.768. Its weak ruby spectrum displayed absorption lines in the red area between 660 and 695 nm, a broad absorption in the green-yellow area between 500 and 600 nm, and two fine lines in the blue area between 460 and 480 nm. It fluoresced a strong patchy orange color under long-wave UV and a weaker orange under short-wave UV. Microscopic examination revealed exsolved rutile as reflective platelets, arrowheads, particles, and needles (figure 2A); loose white particle clouds arranged in geometric and stacked patterns (figure 2B); a series of twinning lamellae (figure 2C); boehmite needles or tubules (figure 2D); and reflective fingerprints with iridescence (figure 2E). No evidence of heat treatment was observed. The stone showed diffused pinkish purple zoning in immersion. This inclusion scene is common in but not limited to sapphires from Sri Lanka, Madagascar, and Myanmar (formerly Burma).
To help with the country of origin determination, we collected laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) chemistry. The results showed very low concentrations of iron, 11–13 ppma, and an unusually high vanadium at 300 ppma.
Several years ago a parcel of color-change sapphires was documented at GIA’s laboratory in Bangkok. That material, which had the same unusual chemistry of low Fe and high V, was from Myanmar. The chemistry profile of our client-submitted stone was consistent with that of the research stones previously documented from Myanmar.
This is the first time the Carlsbad lab has encountered a color-change sapphire with such a unique chemistry profile. LA-ICP-MS again proved to be a useful tool for gemstone origin determination, especially when the inclusion scenes of different localities overlapped. @chapter:12


Publication Year: 2000 Title: Characteristics of Nuclei in Chinese Freshwater Cultured Pearls Abstract: There has been considerable debate in the gem trade concerning the nucleation procedures being used to grow large round Chinese freshwater cultured pearls (FWCPs). Of particular concern are claims that most of these cultured pearls are nucleated by reject mantle-tissue-nucleated FWCPs, and that such a product would be difficult to separate from normal tissue-nucleated cultured pearls and in some cases from natural pearls. However, field research indicates that many Chinese growers are currently using larger mussels (Hyriopsis cumingi), combined with new tissue-insertion techniques, to grow larger, better-shaped FWCPs. For this study, X-radiographs of approximately 41,000 Chinese freshwater cultured pearls from dozens of farms were examined, and 10 samples were sectioned. All showed evidence of mantle tissue nucleation only; the presence of a bead, whether shell or a tissue-nucleated FWCP, would be identifiable by distinctive features seen in the X-radiograph. @chapter:14


Publication Year: - Title: Winter 2009 G&G Book Reviews Abstract: “Emeralds: A Passionate Guide: The Emeralds, the People, Their Secrets”
By Ronald Ringsrud, 382 pp., illus., Green View Press [www.emeraldpassion.com], Oxnard, CA, 2009. $80.00

“The French Blue”
By Richard W. Wise, 489 pp., illus., publ. by Brunswick House Press [www.thefrenchblue.com], Lenox, MA. $29.95

“The Pearl Oyster”
Edited by Paul C. Southgate and John C. Lucas, 582 pp., illus., publ. by Elsevier [www.elsevier.com], Amsterdam, The Netherlands, 2008. 91.95 (US$111.00)

“Collector’s Guide to Fluorite”
By Arvid Eric Pasto, 96 pp., illus., publ. by Schiffer Publishing [www.schifferbooks.com], Atglen, PA, 2009. $19.99

“The Bohemian Crown Jewels”
By Andrej Sumbera, transl. by Zuzana Jurgens, 114 pp., illus., publ. by the author
[www.korunovacni-klenoty.cz], 2008, $20.00

To view the full section, download the PDF above. @chapter:26


Publication Year: 2014 Title: UV-Reactive Opal Abstract: Figure 1. Note the milky white color of these two polished opals before exposure to long-wave ultraviolet light. Photo by Don Mengason.

              A pair of milky white polished opals, weighing 2.66 and 2.48 ct, were recently examined at the Carlsbad laboratory (figure 1). Spot RI readings of 1.44 and 1.43, respectively, were consistent with opal. The stoneswere placed under long-wave ultraviolet light (LWUV) as part of the routine testing.

Upon removal from the UV light source, it was apparent that the opals’ color had changed to a bright orangy red. Further gemological testing confirmed that the specimens had been impregnated with an unknown photochromic substance that changed color when exposed to UV light. The color change (figure 2) occurred after approximately one minute of exposure. The orangy red color faded completely about five minutes after removal from the UV source. Furthermore, when the specimens were placed near a window, sunlight provided enough UV radiation to fully induce the orangy red color. This reversible and repeatable effect, known as tenebrescence, is occasionally seen in natural materials, most notably hackmanite. Exposure to the light of an incandescent bulb faded the color faster, which is another property of tenebrescence. Exposure to short-wave UV did not produce any visible effect on the color.

	Figure 2. The same two opals are shown after exposure to long-wave UV. Photo by Don Mengason.
The fact that hydrophane opal allows foreign substances to be introduced has already been established (N. Renfro and S. McClure, “Dyed purple hydrophane opal,” Winter 2011 G&G, pp. 260–270). This was in the context of dyeing with a substance that altered the appearance of the bodycolor, but did not change color in the presence of UV light. Impregnating opal with a UV-reactive chemical to make the opal appear to be tenebrescent has not been previously documented. Whether the substance used to impregnate the opals affected the original color or transparency is not known, nor is the stability of the treatment. @chapter:39


Publication Year: - Title: Video Feature: 2013 Hong Kong Jewelry & Gem Fair Abstract: A view of Hong Kong, a leading global trade port. Stock photo.

                      The former British colony of Hong Kong, now a Special Administrative Region of the People’s Republic of China, is one of the world’s top ten importers and exporters. Almost half of Hong Kong trade is with mainland China, which makes it a very attractive site for global gem and jewelry trade shows. The fact that it is a free trade port with no tariffs and minimal licensing also draws suppliers and buyers. Alongside Las Vegas and Basel, Switzerland, Hong Kong’s gem and jewelry shows rank as one of the world’s most important in terms of size, trading, and industry trendsetting.

The former British colony of Hong Kong, now a Special Administrative Region of the People’s Republic of China, is one of the world’s top ten importers and exporters. Almost half of Hong Kong trading is with mainland China, which makes it a very attractive site for global gem and jewelry trade shows. Being a free trade port with no tariffs and minimal licensing also draws suppliers and buyers. Alongside Las Vegas and Basel, Switzerland, Hong Kong’s gem and jewelry shows rank as one of the world’s most important in terms of size, trading, and industry trendsetting.

	Wolfram Diener Talks About UBM's Trade Shows in Asia

	Wolfram Diener, UBM’s Senior Vice President, gives an interview at Hong Kong’s 2013 Jewellery & Gem Fair about why UBM, the biggest commercial exhibition organizer in mainland China, is attracted to Hong Kong for trade shows.
Three main Hong Kong shows are held every year. The first is usually in March, followed by another in June. The September show is the largest, with two venues needed to accommodate all the exhibitors. The June and September events are organized by UBM, a global communications and marketing firm. This year’s June show, the 26th annual Hong Kong Jewellery & Gem Fair, was held at the Hong Kong Convention and Exhibition Center (HKCEC), concurrently with Asia’s Fashion Jewellery and Accessories Fair. It featured several theme pavilions, including diamonds, colored stones, jadeite, pearls, fine jewelry, antique jewelry, design, and manufacturing tools.

	David BindraA Colored Stone Dealer's Perspective

	David Bindra of Los Angeles' B&B Fine Gems gives his perspective on the growth of the September gem show in Hong Kong, which he said has become the "epicenter" of colored gem trading.
Approximately 40,000 buyers attended the June show, a figure that typically reaches 60,000 for the September event. While the buyers represented a truly international mix, the percentage from China has consistently increased. As the country’s wealth continues to soar, the rise of a consumer economy has led to strong gains in gemstone and jewelry purchases. The Chinese consumer is becoming more sophisticated and demands higher-quality diamonds, gemstones, and jewelry.

Western designs and brands are also popular in China, which has created opportunities for international suppliers, including diamond dealers and gold jewelry manufacturers. China is the world’s largest buyer of gold. With its free trade policies, geographic location, and tradition as a gateway to China, Hong Kong is poised to remain Asia’s largest trading hub for fine jewelry, as well as a top destination for international suppliers and buyers. @chapter:27


Publication Year: 2023 Title: “Atypical Beads”: Variations of Two Types of Nuclei Abstract: Figure 1. Four loose atypical bead cultured pearls weighing 3.30 to 8.53 ct. Pearls 1–4 are shown from left to right. Photo by Gaurav Bera.
Atypical bead cultured pearls (aBCP) are occasionally encountered during laboratory testing. The nuclei used can take the form of various undrilled, partially drilled, or even drilled materials including natural pearls (abalone, scallop, turban species, Pteria species, and Pinna species), freshwater non-bead cultured pearls, coral, plastic, small shells, faceted sapphire beads of various colors, glass, quartz, and agate (“Atypical ‘beading’ in the production of cultured pearls from Australian Pinctada maxima,” GIA Research News, February 13, 2017). Four aBCPs (figure 1) were recently discovered in a group of 50 loose pearls submitted to GIA’s Mumbai laboratory.
Externally, the four white to light cream-colored aBCPs looked similar to the other pearls submitted in the lot. When viewed under 40× magnification, their surfaces exhibited a typical nacreous surface of overlapping aragonite platelets. Energy-dispersive X-ray fluorescence spectrometry on all four revealed manganese levels between 13.30 ppm and 45.60 ppm and strontium levels between 1064 ppm and 1822 ppm, characteristic of a saltwater environment. Interestingly, optical X-ray fluorescence (XRF) of pearl 1 revealed a strong yellowish green reaction, while pearls 2, 3, and 4 were inert. The ultraviolet/visible reflectance spectra collected on the four pearls showed weak absorption features at around 320–420 nm. Raman analysis using 514 nm laser excitation showed the expected doublet at 702/705 cm–1 and peak at 1085 cm–1, indicative of aragonite.

Figure 2. Surface appearance and internal structures of the four atypical bead cultured pearls. Photomicrographs by Nishka Vaz; fields of view 2 mm, 0.6 mm, 2.86 mm, and 16.3 mm.

Figure 3. Left: Pearl 1 revealed a strong yellowish green reaction under optical X-ray fluorescence. Right: Undulating shell banding visible within the sample’s shell bead nucleus using transmitted light. Photomicrograph by Nishka Vaz; field of view 6.75 mm.
Real-time microradiography (RTX) and X-ray computed microtomography (μ-CT) analysis revealed a variety of internal structures that required interpretation. RTX imaging of pearl 1 showed a thin irregular demarcation close to the surface which was not continuous. On viewing the μ-CT, the demarcation was more discernible and followed the irregular outline of the pearl (figure 2, row 1). An irregularly shaped freshwater shell bead was clearly used as the nucleus, hence the strong yellowish green reaction observed in the optical X-ray fluorescence unit (figure 3, left). Under transmitted light, banding within the bead nucleus was also observed (figure 3, right); externally, the pearl had notable indentations on its surface.
Pearl 2 hosted the most interesting nucleus of the four. A rectangular “tissue-box” shaped bead, likely a piece of cut saltwater shell given the almost identical radio-opacity to that of its host, was evident in the RTX and μ-CT images (figure 2, row 2) (Fall 2022 Gem News International, pp. 378–380). Externally, the pearl was smooth, lustrous, and free of any surface blemishes.
The RTX and μ-CT images of pearl 3 revealed an obvious demarcation with a linear structure at the center of the nucleus and a small “organic tail-like feature” at one end within the boundary separating the bead from the overgrown cultured nacre (figure 2, row 3). All features were consistent with a saltwater non-bead cultured pearl being used as the bead nuclei. The lack of growth arcs around the demarcation was possibly due to rapid nacre deposition during the culturing process (“Atypical ‘beading’ in the production of cultured pearls from Australian Pinctada maxima,” GIA Research News, February 13, 2017). This pearl exhibited distinct surface scratches that were visible without magnification.
Pearl 4 also showed a strong demarcation feature on the RTX and μ-CT images. However, the central area differed from the other three pearls, as it showed a void-like feature in the middle (figure 2, row 4). The bead nucleus used in the process was most likely a saltwater non-bead cultured pearl based on the fact that the pearl was inert to XRF, in keeping with pearl 3, despite the relatively thin nacre layers that would allow a freshwater bead to react. The pearl was also unusual because it possessed three nearly flat “bases” with concave features at the center of each. This raised questions about its identity even before X-ray examination, since the authors have rarely observed natural pearls with such features.
This is not the first time GIA has encountered aBCPs, but to receive four with variations on two types of nuclei—atypical shell (not typical round shell beads) and non-bead cultured pearls—in one lot was very interesting. This proves that such pearls are still circulating in the market and are being mixed with natural goods in an attempt at deception (Fall 2011 Lab Notes, pp. 229–230). Given the spectral data collected (S. Karampelas, “Spectral characteristics of natural-color saltwater cultured pearls from Pinctada maxima,” Fall 2012 G&G, pp. 193–197) and the pearls’ internal structures and external appearance (A. Homkrajae et al., “Internal structures of known Pinctada maxima pearls: Cultured pearls from operated marine mollusks,” Fall 2021 G&G, pp. 186–205), it is apparent that all four of them formed within Pinctada species mollusks, most likely Pinctada maxima. Atypical bead cultured pearls have always been an interesting and sometimes challenging subject. With modern equipment and practical pearl testing experience, laboratories such as GIA aim to remain one step ahead of the possible experiments used by cultivators. @chapter:14


Publication Year: 2023 Title: Forsterite in a Purple Tanzanian Spinel Abstract: Figure 1. This faceted purple spinel, weighing 0.51 ct and measuring 5.20 × 4.17 × 3.10 mm, was reportedly from Tanzania. Photo by Jinlin Wu.
Purple/violet spinel from Tanzania is popular in the gem market today. Recently, author JW encountered an oval-shaped purple gemstone reportedly from Tanzania (figure 1). Its refractive index of 1.714 and hydrostatic specific gravity of 3.59 indicated spinel. Its ultraviolet/visible/near-infrared (UV-Vis-NIR) absorption spectrum was characterized by a series of absorption bands centered at 555 nm and several iron-related small bands centered at around 371, 385, 461, and 478 nm, as well as an extremely weak band at ~625 nm for Co2+ (figure 2). This absorption profile revealed that iron (Fe2+ and Fe3+) was the main coloring element (P.M. Belley and A.C. Palke, “Purple gem spinel from Vietnam and Afghanistan: Comparison of trace element chemistry, cause of color, and inclusions,” Fall 2021 G&G, pp. 228–238).

Figure 2. The UV-Vis-NIR spectrum of the spinel sample shows absorption peaks mainly related to Fe2+ and Fe3+.
Energy-dispersive X-ray fluorescence analysis was performed to determine the sample’s trace element concentration, which showed 10950 ppmw iron, 963 ppmw zinc, 52 ppmw chromium, 94 ppmw vanadium, and 9 ppmw cobalt. These results were similar to the chemical features of representative purple Tanzanian spinel: extremely high iron content, medium zinc content, and low chromium and vanadium contents (G. Giuliani et al., “Pink and red spinels in marble: Trace elements, oxygen isotopes, and sources,” Canadian Mineralogist, Vol. 55, No. 4, 2017, pp. 743–761).

Figure 3. A colorless subhedral forsterite (Fo) inclusion and a dolomite (Dol) inclusion with an unknown dark material attached. Photomicrograph by Jinlin Wu; field of view 0.66 mm.

Figure 4. Oriented short needles in the spinel. Photomicrograph by Jinlin Wu; field of view 1.10 mm.
Microscopic observation revealed a colorless subhedral mineral, a dolomite with an unknown dark material attached (figure 3), and oriented short needles (figure 4). Raman spectroscopy identified the colorless mineral as forsterite. According to the RRUFF database (B. Lafuente et al., https://rruff.info/about/downloads/HMC1-30.pdf), peaks at 822, 855, 918, and 963 cm−1 were consistent with the main peaks of forsterite (figure 5).

Figure 5. Comparison of Raman spectra of the colorless mineral and forsterite in the RRUFF database. Peaks in the inclusion spectrum at 312, 405, 664, and 766 cm–1 are from the host spinel. Spectra are offset vertically for clarity.
As a rock-forming mineral, forsterite (Mg2SiO4) itself is common, especially in marble-hosted spinel. However, it is rarely observed in Tanzanian spinel and has been reported only once to our knowledge (E. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Volume 2, Opinio Publishers, Basel, Switzerland, 2005, 829 pp.).
In Tanzania, the primary deposits of spinel occur in marbles and calc-silicate rocks that belong to the Neoproterozoic metamorphic Mozambique Belt (G. Giuliani et al., “Les gisements de rubis et de spinelle rouge de la Ceinture Métamorphique Néoprotérozoıque Mozambicaine,” Revue de Gemmologie, Vol. 192, 2015, pp. 11–18). Under high-temperature conditions, spinel and forsterite are both stable mineral phases in marbles (Giuliani et al., 2017). Spinel is found in marble or impure marble associated with calcite, dolomite, forsterite, clinohumite, and phlogopite in deposits in Myanmar and Vietnam. Thus, forsterite is commonly seen as an inclusion in spinel from these sources (G. Giuliani et al., “Pink and red gem spinels in marble and placers,” InColor, No. 43, 2019, pp. 14–28).
It was noteworthy to see forsterite in the Tanzanian sample. This finding could indicate a similar formation environment between spinel in Tanzanian deposits and those in Myanmar and Vietnam. @chapter:5


Publication Year: 1990 Title: Winter 1990 Gem News International Abstract: Diamonds
            DeBeers Announces World's Largest Synthetic Diamond Crystal
            China-Cut Diamonds Sold in Singapore
            Guyana Mining Development
Colored Stones
            Possible Foreign Participation in Afghan Mining
            Novel Assembled Stone
            Black Coral Industry on the Mexican Caribbean
            Update on Sapphire Mining in Kanchanaburi
            Peace Pact for Colombian Emerald Region
            Unusual Color-Zoned Garnet
            Heavy Liquids Studied in Australia
            Black Cat's-Eye Opal
            Exceptionally Large White Opal
            Color-Change Cobalt Spinel
            Large Topaz Sculpture
            Cat's-Eye Bicolored Tourmaline
            More Gems from the USSR?
Enhancements
            Diffusion-Treated Sapphire Update
            "Rainbow" Quartz: A New Enhancement
            Jade "Processing"
Synthetics and Simulants
            Natural-Appearing Synthetic Cabochons
            Thailand Cutting CZ
            Glass Imitation Jadeite
            A Glass Imitation Pectolite?
            Dyed Quartz Imitation of Sugilite?

To view the full section, download the PDF above. @chapter:23


Publication Year: 2018 Title: Book Review: Dreher Carvings: Gemstone Animals from Idar-Oberstein Abstract: By Wilhelm Lindemann, Will Larson, and Ekkehard Schneider. Hardcover, 240 pp., illus., publ. by Arnoldsche Verlagsanstalt, Stuttgart, Germany, 2018, $85.00.

Dreher Carvings: Gemstone Animals from Idar-Oberstein begins with a history of the lapidary arts of this region of southwest Germany, which is also the timeline of the Dreher family gem-carving tradition. The various authors describe the driving forces behind the development of this world-renowned lapidary area, and the impetus for the Dreher’s unique style has followed a very similar path. What began as a subsistence-level job for many residents of Idar-Oberstein developed into an art form as tools evolved, skills improved, and a growing client base provided the financial cushion needed to pursue their vision.
This progression is described in the early portions of the book, and it is mentioned or alluded to by several of the authors in their narratives. Idar’s earliest gem cutters worked to survive. They used sandstone to render agates into functional, and eventually, decorative items. Stone cutting became the backbone of the area’s economy. Over time, harder and more accurate cutting wheels allowed for faster, higher quality production. Mechanical advances brought about the water wheels that powered this industry for centuries. The stonecutting work evolved into contract work for merchants supplying the jewelers and studios with finished gemstones, which led to an era of prosperity starting in the fifteenth century.
Idar’s stone carvers were traditionally considered craftsmen rather than artists because they were not creating original pieces. The work was regarded as rote and unimaginative, easily reproduced, but this simplicity was desirable to their buyers. Pieces were styled after templates and models supplied by clients, such as the House of Fabergé. The economic models came from merchants who saw value in repeatability, consistent design themes, and competition for the contracts, which could be filled by any qualified lapidary. This arrangement was also associated with the dissolution of the guild system, in which secret techniques and tools were known only to members. In the early nineteenth century, local mining resources were exhausted, and it was necessary start importing rough, mostly from Brazil. This new material added a dimension to the creativity of the carvers. Later in the 1800s, many Idar-Obersteiners joined apprenticeships and opened studios in Paris to practice their art and reach their audience. The German stonecutters were expelled from France during the Franco-Prussian War in 1870-71 and returned home to establish Idar-Oberstein as a world center for gemstone carving. Gem cutters started to be recognized in the mid-twentieth century as artists, as appreciation of stone carving as a classical fine art developed. This could be called the advent of gem carving’s creative movement, where the rough, the concept, the techniques, and the artist come together to create masterpieces. This is the situation that the most recent generations of Drehers (Gerd and Patrick Dreher) have enjoyed.
After returning from World War II, Paul Dreher, father of Gerd Dreher, began to carve his own designs in addition to the commissions that were his primary income. These personal pieces gave the House of Dreher a reputation as an artistic studio. In 1960, Gerd abandoned the “proto-industrial tradition” and the templates that controlled the design ethos in Idar and focused on creating his own designs. Up to that point, the Drehers had focused on the techniques and skills that made them a well-respected lapidary house, but one that was mostly known for actualizing the designs of others, usually from a template or model, but Gerd Dreher’s concept involved a subjective view of nature that is a confluence of the subject, the artist, and the material. Due to by the popularity of their carvings, the Drehers were freed from the economic restraints that are the primary consideration when carving gemstones. The use of signatures on their work, starting in 1975, has been the physical validation of cultural recognition of their work as art, not craft.
Gerd Dreher specialized in showcasing the natural beauty of the raw material, and his son Patrick has followed suit. Ironically, their subject matter often includes creatures not usually associated with beauty, such as warthogs, toads, mice, and hippos. But they are all so lifelike, imbued with personality. Every detail of their forms exemplifies beauty. The synergy of the raw material, its colors and conformation, and the structure of the subject matter, is what animates the Drehers’ work. The planning, design, layout, and all of the grinding and polishing steps, which take hundreds of hours, are embodied in these immortal creatures.
Robert Weldon’s outstanding photography gives another dimension to the carvings. Weldon somehow creates an image that speaks to the viewer. The artists create the pieces, and the photography makes the pieces’ personalities more accessible to the public. Weldon’s narrative is technically informative and insightful.
The chronological order of the photos is an excellent detail of the book. The progression of Gerd’s technique is visibly illustrated, and the reader can follow Patrick’s progress as well. as the Drehers become more successful, the rough material becomes more and more fabulous. Advances in technology are obvious as the detail work improves from piece to piece: the bumps get closer together, and the polish becomes more consistent and thorough. Each piece is more sophisticated than the last.
On some level, the guild mentality still exists. The technical details of their workshop are extremely vague, and the description of the tools used is outdated. The Drehers continue to closely guard all information about their polishing processes. This is often the case with modern lapidaries, where cutters fear competitors’ advantage. Although this book was created to showcase the art and prolific portfolio of the Drehers, there would be considerable interest in more of the technical details of their work.
The homages to the family are a very nice touch: the tribute from another gem artist, personal vignettes by important industry leaders, and tales of their meetings and contacts with the Drehers. These stories combine to detail the journey their carvings have taken to become some of the most important gemstone art of the modern era. The homages tell of the eventual acceptance of their art in worldwide venues of fine gemstones including other parts of Germany, Russia, and the United States. Other important writers include collectors of these pieces, who speak of the Drehers’ commitment to their work.
The variety of narratives in this volume gives the reader many perspectives into the Dreher story and their carvings. It is enlightening to read the history of the family and understand the genesis of their art. What is lacking is a consistent narration, a voice throughout to link all of the speakers. It is left to the reader to piece it all together. It is marvelous that this excellent book has been published, as it validates gemstone carving as a fine art. The production values are beyond reproach, and the color and quality of the images is outstanding. This historic volume will surely need a sequel in the coming years as Patrick Dreher continues to work. @chapter:26


Publication Year: 2015 Title: Synthetic Sapphire with Diffusion-Induced Color and Star Abstract: Figure 1. This 24.58 ct star cabochon was a colorless synthetic sapphire whose color and star had been induced by diffusion treatment. Photo by Sutas Singbamroong.

The Dubai Central Laboratory recently examined an asteriated blue oval cabochon that weighed 24.58 ct and measured 17.37 × 14.61 × 9.59 mm. The client submitted the sample for an identification report and origin determination.

The cabochon appeared to be completely transparent, evenly colored, and clean. Fiber-optic lighting revealed two sharp, six-rayed white stars with long, straight arms of equal length. The stars seemed to float over the dome surface with internal reflection from the base, very similar to those typically seen in synthetic star sapphires (figure 1).

Standard gemological testing established the following properties: spot RI—1.76; pleochroism—distinct light green and bluish violet (viewed parallel to the girdle); hydrostatic SG—3.98; and fluorescence—inert to both long- and short-wave UV radiation. No characteristic absorption spectrum was seen with a desk-model spectroscope; a faint absorption band was observed at about 560 nm. These properties were consistent with sapphire, though the sample did not show the Fe line at 450 nm commonly seen in natural blue sapphire. Observation of the cabochon immersed in water with diffused transmitted light revealed shallow coloration and a colorless circular area of repolishing (figure 2). This suggested that the specimen owed its color to a diffusion process. The melted appearance of the cabochon’s base confirmed that it had been subjected to the heat required for diffusion treatment. Microscopic examination showed only a few small melted fingerprint-like inclusions near the surface, and very fine oriented needle-like inclusions confined to a shallow layer below the surface (figure 3). No curved color banding or angular color zoning was present. Higher magnification indicated that the oriented needles were approximately 5–25 microns long. Further examination with immersion in methylene iodide between crossed polarizers, viewing parallel to the optic axis direction, uncovered the distinct Plato lines strongly indicative of Verneuil synthetic origin.

Figure 2. Immersed in water and viewed with diffused transmitted light, the star cabochon
showed shallow coloration with a colorless circular area of repolishing. This feature, along
with the melted appearance of the base, indicated that the color and asterism had been
produced by a diffusion process. Photo by Sutas Singbamroong.

Figure 3. Very fine oriented needle-like inclusions causing the star were confined to a
shallow layer below the surface. Photomicrograph by Sutas Singbamroong, magnified 25×.
EDXRF chemical analysis revealed traces of Ti, Fe, and V; no Ga, Cr, or other trace elements were detected. Unoriented UV-Vis-NIR absorption spectroscopy showed two broad bands, one centered at about 330 nm due to Fe3+ ions, and one with maxima at about 565 nm due to Fe2+-Ti4+ intervalence charge transfer (figure 4). No Fe3+-related sharp bands at approximately 375, 390, and 450 nm were seen.

Figure 4. An unoriented UV-Vis-NIR spectrum of the diffusion-induced star synthetic
sapphire exhibited two broad bands centered at about 330 and 565 nm, the latter of which
is typically responsible for sapphire color.
This combination of properties and features indicated that colorless synthetic sapphire was used as a starting material, and both the color and the asterism were produced by a diffusion process. @chapter:12


Publication Year: 1989 Title: Spring 1989 G&G Book Reviews Abstract: “Jewelry of the 1940s and 1950s”
By Sylvie Raulet, 332 pp., illus., publ. by Rizzoli International Publications, New York, 1988. US$100.00

“Color Encyclopedia of Gemstones, 2nd Edition”
By Joel E. Arem, 280 pp., illus., publ. by Van Nostrand Reinhold Co., New York, 1987. US$53.95

“Antique and Twentieth Century Jewellery, a Guide for Collectors, 2nd Edition”
By Vivienne Becker, 319 pp., illus., publ. by N.A.G. Press Ltd., Colchester, Essex, Great Britain, 1987. US$45.00

“Jewelry & Gems: The Buying Guide”
By Antoinette L. Matlins and Antonio C. Bonanno, 206 pp., illus., publ. by Gemstone Press,
South Woodstock, VT, 1987. US$14.95

“Mineral Museums of Europe”
By Ulrich Burchard and Rainer Bode, 269 pp., illus., publ. by Walnut Hill Publishing Co., 1986.
US$49.50

“Descriptions of Gem Materials, 3rd Edition”
By Glenn and Martha Vargas, 180 pp., illus., publ. by Glenn and Martha Vargas, Thermal, CA, 1985. US$15.00

“The Jade Kingdom”
By Paul E. Desautels, 118 pp., illus., publ. by Van Nostrand Reinhold Co., New York, 1986. US$37.95

To view the full section, download the PDF above. @chapter:26


Publication Year: 2014 Title: New Deposit of Black Opal from Ethiopia Abstract: ABSTRACT
Opal was first discovered in Ethiopia in the early 1990s. Specimens from Mezezo in the historical Shewa province consist of nodules of a reddish brown volcanic rock with orange, reddish brown, or “chocolate” brown precious opal inside. The next major discovery occurred in 2008, when white precious opal was found in the province of Wollo near Wegel Tena, about 550 km north of Addis Ababa (F. Mazzero et al., “Nouveau gisement ďopales ďEthiopie dans la Province du Welo: Premières informations,” Revue de Gemmologie a.f.g., No. 167, pp. 4–5). This deposit still produces large amounts of white and crystal precious opal and occasionally some black material (Winter 2011 Lab Notes, pp. 312–313).

In 2013, yet another source was discovered in Wollo, at the Stayish mine near the town of Gashena (figure 1). This discovery has yielded mostly dark and black opal, along with some white and crystal opal. Although it is only now being reported, the deposit has been actively producing since 2013. It is set in a distinct opal-bearing layer in a mountainous area at an altitude of around 3,000 meters. It lies approximately 700 km northeast of Addis Ababa, more than 100 km from the historic town of Lalibela by road, and about 30 km north of the white opal deposit.

Figure 1. The Stayish black opal mine, active since 2013, is located in the Wollo province of northern Ethiopia.
Like the white opal, the black opal is found at the contact zone between the volcanic rock series and the underlying clay-rich layer (figure 2). The layer is one in a sequence of repeating volcanic ash and ignimbrite layers. Field observations at different locations show that the opal-bearing layer is contained in a single stratum extending for tens and even hundreds of kilometers along the mountain belt. The opal-bearing clay layer is about 60 cm thick and contains opal of various quality and color. The black opal is retrieved from flat tunnels up to 15–20 meters long that are dug horizontally into the mountain slope by local villagers. The material generally comes in nodules and chunks 2–5 cm long, but 10 cm pieces have also been retrieved from this deposit (figure 3).

Figure 2. While acidic ash layers occur repeatedly within the stratigraphic sequence at Stayish, precious black opal occurs only in this stratum. Photo by Pierre Hardy.

Figure 3. Pieces of black opal from the Stayish mine are usually 2–5 cm in diameter (bottom), though some may reach 10 cm in length (top). Photo by Tewodros Sintayehu.
The specimens are usually very dark, reminiscent of dyed or smoke-treated opal except that the surface does not show any staining in surface pits or fissures (figure 4). The stones also display a dark, even color all the way through and are sometimes layered with dark gray common opal. This separates it from sugar-acid treated opal (Winter 2011 GNI, pp. 333–334), where the darker color is confined to a more or less thick surface layer.

Figure 4. This microscopic image of an Ethiopian black opal with surface scratches shows none of the black staining seen in smoke-treated or dyed opal. Some grayish non-precious opal material can be observed between the color patches. Photo by Hpone-Phyo Kan-Nyunt.
Initial X-ray fluorescence analyses showed barium (Ba) values ranging from below detection limit for one deposit with more crystal-like opal to 1000 ppmw for another deposit with more dense and grayish material. The two deposits are on adjacent sides of the same mountain. The wide range of Ba values confirmed the volcano-sedimentary character of the black opals, as previously described for white opals from Wegel Tena (B. Rondeau et al., “Play-of-color opal from Wegel Tena, Wollo Province, Ethiopia,” Summer 2010 G&G, pp. 90–105).

Preliminary studies with Fourier-transform infrared (FTIR) spectrometry did not give conclusive results due to the relatively opaque character of our samples. Raman spectra showed very strong carbon peaks, though these alone do not allow a reliable distinction between treated opal from Wegel Tena and natural-color black opal from the Stayish mine. Careful microscopic observation should reveal the natural character of opal from this new deposit, and further studies are in progress. @chapter:39


Publication Year: 2017 Title: Brazil’s Enigmatic Diamonds, Cuprian Liddicoatite, and Silicon in Corundum Abstract: Welcome to the first Gems & Gemology of 2017! This is an unusually diverse issue, combining Brazilian diamonds, cuprian liddicoatite tourmaline, Japanese jadeite, iris quartz, synthetic zincite, and a short but important contribution on the fundamental role of the element silicon in generating blue color in many fine sapphires.

		The original geologic sources of Brazil’s most valuable diamonds remain elusive...

	In our lead article, authors Darcy Svisero, James Shigley, and Robert Weldon survey Brazil’s diamond deposits. This region has produced a significant number of large rough diamonds. It’s also a source of valuable colored diamonds from predominantly alluvial deposits, but today’s diamond production is small and the original geologic sources remain mostly elusive. Although economically viable kimberlite pipes have been discovered in recent years, the outlook for increased production appears challenging.

	Most researchers assume the bulk of copper-bearing tourmaline on the market today is elbaite, but some is undoubtedly another tourmaline species: liddicoatite. Yusuke Katsurada and Ziyin Sun report on the chemistry of copper-bearing liddicoatite tourmaline submitted to GIA’s Tokyo laboratory. Their study shows elevated gallium and lead content in cuprian liddicoatite, which displays stronger fluorescence under long-wave ultraviolet light than cuprian elbaite due to high concentration of rare earth elements.

	In our third paper, John Emmett, Jennifer Stone-Sundberg, Yunbin Guan, and Ziyin Sun discuss the critical role of silicon in the color of gem-quality corundum. Although the effect of trace elements such as iron, titanium, and magnesium within the corundum lattice is well understood, the chemical interaction of these trace elements is not widely appreciated. The authors demonstrate that silicon’s presence is vital to the process that allows titanium to pair with iron and create blue color in sapphire. To the best of the authors’ knowledge, this topic has not been addressed in the gemological literature.

	Our next paper, by Ahmadjan Abduriyim, Kazuko Saruwatari, and Yusuke Katsurada, covers the history and characteristics of Japanese jadeite and compares this highly valued gem with jadeite from other sources. Their study examines the chemical composition and chromophores of jadeite varieties from the Itoigawa and Omi regions of Niigata Prefecture and the Wakasa region of Tottori Prefecture and compares them with samples from Myanmar, Guatemala, and Russia.

	Next, Xiayang Lin and Peter Heaney analyze iris quartz crystals from geodes in the Deccan Trap basalts of west-central India using scanning and transmission electron microscopy and atomic force microscopy. Their investigation reveals that certain crystal faces exhibit etching, which acts as a diffraction grating to produce iridescence.

	Our final paper, by Ji Zhang, Yujie Gao, and Guanghai Shi, provides a gemological characterization of an intriguing industrial by-product: gem-quality synthetic zincite from foundries in Poland.

	Be sure to investigate our three regular sections: Lab Notes documents GIA staff gemologists’ most recent findings, Micro-World reveals fascinating gemstone inclusions, and this issue’s Gem News International reports on the 2017 Tucson gem shows, including an important update on Ethiopian emerald.

	We offer congratulations to the winners of our 2016 Dr. Edward J. Gübelin Most Valuable Article Award, and thank all of the readers who voted. Don’t forget to take this year’s G&G Challenge, our annual multiple-choice quiz. Thank you for all your support through 2016! @chapter:0


Publication Year: - Title: Sunstone Description Abstract: A graceful carving displays this Oregon sunstone’s bright, reflective copper inclusions, its intense color, and its pleochroism. – Robert Weldon, courtesy Oregon Sunstone

                      Gem connoisseurs and innovative jewelry designers often seek the subtle beauty of lesser-known—but still intriguing and unique—gemstones. Some of those are members of the feldspar group.

The feldspar group’s wide variety of unusual gems includes moonstone, non-phenomenal orthoclase, phenomenal and non-phenomenal labradorite, sunstone, and amazonite. Of these feldspars, moonstone is a constant favorite, while sunstone from Oregon is gaining attention as a natural and untreated product of the United States.

Although sunstone and moonstone are both members of the feldspar group, the resemblance stops there. While cool moonstone’s phenomenal varieties offer a soft and gentle adularescent glow, warm sunstone’s phenomenal varieties show a distinct and lively glitter called aventurescence.  Aventurescence is a sparkly, metallic-looking luster caused by flat, reflective inclusions, sometimes called “schiller” by sunstone fanciers.

	Copper inclusions create a schiller effect in this Oregon sunstone from the Ponderosa Mine. – Eric Welch, courtesy Desert Sun Mining & Gem Co., Inc.
The feldspar group has many members. Some are suitable for jewelry use, some aren’t. Members of the feldspar group vary slightly in chemical composition, and those variations produce a variety of gemstones that differ widely in appearance.

There are two main branches of the feldspar family tree—feldspars that contain potassium and feldspars that contain a mixture of calcium and sodium.

Two species of feldspars contain potassium. These are orthoclase, which includes the gem varieties moonstone and orthoclase sunstone; and microcline, which includes the gem variety amazonite. A non-phenomenal form of orthoclase feldspar appears in jewelry on rare occasions. Sometimes faceted, its hue is usually a transparent yellow.

Plagioclase feldspars contain a mixture of calcium and sodium, and they have slightly different compositions. The gem species in this feldspar family include labradorite and oligoclase.

	Rough Oregon sunstones display a variety of colors in a range of tones from light to dark. – Valerie Power, courtesy Desert Sun Mining & Gem Co., Inc.
Not all feldspars that bear the name “sunstone” are from the same side of the feldspar family—both the orthoclase and the plagioclase species boast a sunstone feldspar variety. The name sunstone refers to the gem’s appearance rather than to its chemical makeup.

There are many sunstone varieties. If aventurescence is present, gemologists call it aventurine feldspar. The aventurine feldspar from India has a red-brown bodycolor and sunny glitter. It’s perhaps the best-known sunstone variety, but that situation has been changing.

	The 2.39-ct. aventurescent sunstone (right) is from the state of Tamil Nadu, in southern India. It’s accompanied by a cat’s-eye moonstone from the same area (left). – Shane F. McClure

	Tiny platelets in this photomicrograph are responsible for the sunstone’s aventurescence.
The US state of Oregon produces a number of sunstone varieties. The increasing supply from the area has made sunstone more available to the general public. Because many of the sunstone types are unique to the rugged high-desert area in South Central Oregon, they’re being marketed as “all-American” gemstones.

	This Oregon sunstone (about 2 cm across) has been fashioned with some matte-finished facets to bring out the appearance of the copper inclusions. – Maha Tannous, courtesy Klaus Schafer
Although most sunstones have yellow, orange, or brown bodycolor, not all sunstones are aventurescent. The appearance of the phenomenon depends upon the size of the inclusions. Small inclusions create a reddish or golden sheen on top of any bodycolor. Larger inclusions create attractive, glittery reflections. Sunstone inclusions can be hematite, copper, or some other mineral.

	The color of these rough and fashioned sunstones is influenced by their inclusions. – Robert Weldon, courtesy Becky Booker

	A suite of gem-quality sunstones from the Ponderosa mine in the US state of Oregon
	shows the range of colors found in that area. – Tino Hammid
In the early 2000s, a material marketed as Tibetan sunstone or Tibetan andesine generated an ongoing controversy. Experts from several gemological laboratories examined the stones, visited the areas said to be their sources, and investigated recently developed gem treatment processes. Their findings indicated that the material might have been pale andesine from Mongolia that had been treated by infusion with copper to give it lively coloring.

	These attractive gems are part of an ongoing controversy. They were represented as untreated plagioclase sunstone from Tibet. – Robert Weldon, courtesy Do Win Development Co. Ltd. @chapter:2


Publication Year: - Title: Active GIA Alumni Members: More Than 100,000 Strong Abstract: Alumni chapter leaders meet up at Hong Kong Jewelry Fair. From left: George Chen, Taiwan chapter vice president; Mark Hsu, Taiwan chapter immediate past president; Li Shi-Chuan, Taiwan chapter president, Julius Zheng, Shanghai chapter president; Vivian Wang, GIA in Taiwan campus director; Mia Florencio, Philippine alumni member; Yihchen Ng, Malaysia chapter president; and Ken Wan, Malaysia chapter vice president.

                      Greetings:

Our alumni association hit a milestone recently when we surpassed 100,000 active members. That is significant for all of us because it gives us more opportunities for networking, mentoring and connecting with more people who have a passion for what we do.

That was brought home to me in the last few months as I was on the road (and in the air) traveling to tradeshows and alumni events in Boston, New York, Chicago and across South Africa. I met many alumni members along the way and in each place I went, I felt their passion for what they do. It was inspiring to hear the stories, aspirations and memories of so many graduates and students, which resonates with my own passion for gemology, which I was fortunate to recognize a long time ago. I love sharing it with so many amazing people across the globe.

While I was busy traveling, our chapters ‒ more than 70 worldwide ‒ were busy doing what they do best ‒ delivering events and education to our alumni worldwide. They have hosted 100 events so far this year, with more than 45 activities since June!

The following are some highlights:

The 5th Global Alumni Forum session took place in late August and continues to grow in measured success and effectiveness for our chapters: 43 alumni leaders from 38 chapters and nine countries participated. We spent the time discussing how to develop and support of our global alumni community.
A visit to Africa – Johannesburg, Cape Town and Gaborone. Three events, featuring GIA updates, research news and gemological history, were hosted for our alumni and the gem and jewelry trade across South Africa. Their success and attendance were extraordinary and we appreciate the lengths many traveled to attend.
40th Reunion – Graduates from the Class of 1974 gathered for a reception, dinner and visit to the new GIA lab and campus location in the International Gem Tower in New York. Attendees eagerly shared stories from the classroom that made us all laugh, their successes and personal notes and remembrances of those who could not attend. Susan Jacques, president and CEO of GIA, and Tom Moses, executive vice president and chief lab and research officer of GIA, also attended the evening celebration.

Here’s some of the chapter news and events that have occurred in recent months:

Tanzania – our newest chapter! – hosted a very successful first event in July.
Social gatherings brought members of the Houston, Malaysia, Metro-Phoenix, Toronto and Vancouver chapters together.
Hong Kong Gem and Jewelry Fair – was a prime meeting spot for chapter leaders from Malaysia, Taiwan, China and Philippines.
Historical jewelry brands, museum collections and archaeogemmology were some of the topics and field trips put together, including: California – Golden Gate’s lecture on Faberge and notable jewels by Fred Feldmesser; a Colorado – Mile High evening with Dr. Jeffrey Post, curator of the Smithsonian Institute; Houston’s field trip to a Bulgari exhibit; Washington D.C. presentations by Dr. Cigdem Lule on archeogemmology, jewelry historians Elyse Zorn Karlin and Gail Brett Levine, and a third historically focused event that featured Helen Serras-Herman on Maya jade.
A private gem and mineral collection viewing and museum tour was the good fortune of our London members.
Colored gems inspired many industry notables to educate our chapters, including: Doug Hucker, CEO of American Gem Trade Association (AGTA) for New England; Edward Boehm on sourcing gemstones for North Carolina; Metro-Phoenix hosted tsavorite expert Bruce Bridges; Professor Robert Stern on ruby and jadeite for Washington D.C.; and author Renee Newman speaking on exotic gems for Michigan and Houston.
Diamond faceting demonstrations and a lecture featuring Mike and Evert Botha, of Embee Diamonds, were held by Mid-Tennessee and Northeast Florida.
Four chapter events tapped into the knowledge and experience of their members. San Diego and Mid-Tennessee featured Blaire Beavers and Gina Latendresse on pearls, and Colorado – Mile High, San Diego and South Carolina featured members’ experiences in gemology and first-hand field gemology travels to Madagascar, South Africa and Namibia.
Films on gems and jewelry created by alumni were featured, including the production journey of the soon-to-be-released film “Mine to Market” by Roger Dery (AGTA Spectrum winner) in Manhattan, and the “Masters of Dreams” documentary by alum and creator Ken McGrath was shared in London.

The documentary film “Masters of Dreams” was the creative work of GIA graduate Ken McGrath, left, who autographs copies for students at the GIA campus in London.

Gemology “hands-on” emerald treatment sessions were held in Michigan by representatives from Gemworld Intl.
Jewelry design events featured famed jewelry designers Paula Crevoshay in Manhattan and Judy Evans in Metro-Phoenix.
The Mexico City chapter hosted their latest Gemstone Safari to see the pearl harvest at Sea of Cortez pearl farms.
GIA laboratory and education representatives spoke, including Nathan Renfro who presented on the micro art of gems in St. Louis; and Claudia D'Andrea, GIA director of education in Thailand, and Kenneth Scarratt, GIA managing director of Southeast Asia and director of the GIA Laboratory in Bangkok, who gave colored gemstone and diamond updates in Malaysia.

Alumni News – take note!

Save the Date! Join us to “Party at the GIA Gem Mine: Rocking Down Under” at the annual Tucson reunion, dinner dance and auction on Feb. 6, 2015. Chapters and individuals can help make this a success with your attendance and support. Consider donating something related to this fun theme. Please contact us for further donation information. Tickets are available; register early and save!
Scholarships are available – Take advantage of the MANY scholarship opportunities available. Simply apply before Oct. 31 by submitting an online application for GIA education scholarships offered around the world including on campus, eLearning and lab classes.

Looking ahead, the fourth quarter will go by in a flash. Lifetime students – enjoy the activities our chapters have planned through the end of the year. Participants in the Continuing Education Recognition Program – remember to complete your lessons before Dec. 31.

Kate Donovan, GIA alumni relations manager, visits Diamond Trading Company
Botswana(DTCB) to deliver a copy of Gems & Gemology to Keneilwe Dihutso, a
diamond grader at DTCB whose photo is featured in the summer 2014 issue. @chapter:34


Publication Year: - Title: Spring 2009 G&G Book Reviews Abstract: “Cartier”
By Hans Nadelhoffer, 352 pp., illus., publ. by Chronicle Books [www.chroniclebooks.com], San Francisco, 2007. US$75.00

“7000 Years of Jewelry”
By Hugh Tait, Ed., 256 pp., illus., publ. by Firefly Books, Buffalo, NY, 2008. US$29.95

“Pegmatites”
By David London, 368 pp, illus., publ. by the Mineralogical Association of Canada [www.mineralogicalassociation.ca], 2008. US$125.00

“Brooches: Timeless Adornment”
By Lori Ettlinger Gross, 192 pp., illus., publ. by Rizzoli International Publications, New York, 2008. US$45.00

“Collector’s Guide to the Epidote Group”
By Robert J. Lauf, 96 pp., illus., publ. by Schiffer Publishing, Arglen, PA, 2008. US$19.99

“World of Gems Conference”
Edited by Richard Drucker, 90 pp., illus., publ. by Gemworld International [www.gemguide.com], Glenview, IL, 2008, US$29.95

To view the full section, download the PDF above. @chapter:26