Publication Year: 2008 Title: Fall 2008 G&G Lab Notes Abstract: A Citrine with Eye-Visible Brazil-Law Twinning
Composite of Coral and Plastic
Black Diamonds Colored by Hydrogen Clouds
Irradiated Diamond: An Easy Call
Natural Type Ib Diamond with Unusual Reddish Orange Color
Observed Oddities in Diamond
“Party” Cloud Formation in Diamond
Pinkish Brown Diamond with Mantle-Mineral Inclusions
Large Emerald-in-Quartz Specimen
Calcite “Melt” in Grossular Garnet
A Rare Yellow Trapiche Sapphire

To view the full section, download the PDF above. @chapter:32


Publication Year: - Title: An In-Depth Gemological Study of Blue Sapphires from the Baw Mar Mine (Mogok, Myanmar) Abstract: Rough and faceted blue sapphires from the Baw Mar mine in Mogok, Myanmar. Photo by Vincent Pardieu/GIA.

Myanmar (formerly Burma) is one of the world’s oldest sources of fine corundum. Over the last decade, the Baw Mar mine increased its production providing the market with a large number of fine blue sapphires. These sapphires have slightly different properties from the classic Mogok sapphires, but have not been studied in great depth.

Researchers from GIA’s Bangkok laboratory analyzed 64 sapphire samples collected during field expeditions to Baw Mar. They investigated gemological properties, inclusion scenes, spectroscopic features, and trace element chemical composition. Results from their study and field observations from the mining area appear in a new article titled “An In-Depth Gemological Study of Blue Sapphires from the Baw Mar Mine (Mogok, Myanmar).”

The sapphires were mined in different parts of the mine and showed different properties. The most striking difference is the color. Sapphires from the northern part of the mine showed a medium-to-dark blue color, while those from the southern area are generally lighter in tone. Trace element concentrations were measured and compared with those from other metamorphic blue sapphire sources such as Sri Lanka and Madagascar. @chapter:0


Publication Year: 2020 Title: Burmese Star Peridot Abstract: Figure 1. The 20.13 ct star peridot (left) and the 7.67 ct peridot exhibiting weak asterism with more prominent chatoyancy (right), presumably due to cutting style. Photos by Bear Williams.
Asterism in peridot is a rare treat that has been reported on occasionally (S. Borg, “An unusual star peridot,” Journal of Gemmology, Vol. 17, No. 1, 1980, pp. 1–4; Summer 2009 Lab Notes, pp. 138–139). In January 2020, Tom Trozzo submitted to Stone Group Laboratories a 20.13 ct oval cabochon peridot (figure 1, left) that exhibited a soft yet prominent four-rayed star. Comparisons were made with an in-house lab sample that also exhibited reflection effects from tiny acicular inclusions. For purposes of this study, this comparison stone was recut to a 7.67 ct pear-shaped cabochon (figure 1, right) to enhance any potential asterism. However, the result appeared to be more of a cat’s-eye effect, presumably due to the prominent keel from the original faceted pear shape. It is presumed that, based on the arrangement and concentration of inclusions, a more prominent asterism will be revealed upon further cutting. Apparent clarity was good on both stones, but with a slightly diffused effect; no large eye-visible inclusions were present. While the asterism was more pronounced on the oval, the acicular inclusions were more plentiful and of higher relief in the pear-shaped stone. Both stones had a yellowish green color, with the oval exhibiting a very slight grayish modifier.

Figure 2. Brownish, acicular inclusions in the 20.13 ct star peridot (left, field of view 4 mm). Short, feathery, whitish needle-like inclusions in the 7.67 ct pear-shaped peridot (right, field of view 3.5 mm). Photomicrographs by Bear Williams.
Microscopic observation of the larger oval peridot revealed evenly distributed concentrations of extremely fine, short, brownish, acicular inclusions oriented in two directions (figure 2, left). In the pear shape, the needles were evenly dispersed throughout and oriented in three directions. The needles were also short and whitish to colorless (figure 2, right). Reflection effects in some materials may be difficult to define. There may be reflection effects from nonacicular inclusions, creating schiller as well as asterism. This was the case with the oval peridot, although asterism was clearly the dominant phenomenon.
The spot RI reading of approximately 1.65 and hydrostatic SG of 3.33 were consistent with peridot. The identification of both peridots was confirmed by Gemmo-Raman532-SG. Their provenance was reportedly Myanmar (Burma), and all tests were consistent with a Burmese origin. Interestingly, all known star peridots to date have been of Burmese origin. Although Pakistani peridot may often feature acicular inclusions of ludwigite, these are presumably protogenetic and not oriented consistently to the crystal structure of the host peridot. @chapter:19


Publication Year: 2009 Title: The “Type” Classification System of Diamonds and Its Importance in Gemology Abstract: Diamond “type” is a concept that is frequently mentioned in the gemological literature, but its relevance to the practicing gemologist is rarely discussed. Diamonds are broadly divided into two types (I and II) based on the presence or absence of nitrogen impurities, and further subdivided according to the arrangement of nitrogen atoms (isolated or aggregated) and the occurrence of boron impurities. Diamond type is directly related to color and the lattice defects that are modified by treatments to change color. Knowledge of type allows gemologists to better evaluate if a diamond might be treated or synthetic, and whether it should be sent to a laboratory for testing. Scientists determine type using expensive FTIR instruments, but many simple gemological tools (e.g., a microscope, spectroscope, UV lamp) can give strong indications of diamond type. @chapter:31


Publication Year: 2016 Title: Mixing of Natural Diamonds with HPHT Synthetic Melee Abstract: Figure 1. These 23 HPHT-grown synthetic diamond melee, ranging from 0.002 to 0.012 ct, were identified recently at GIA’s Hong Kong lab. Photo by Johnny Leung and Tony Leung.

	In recent years, significant amounts of colorless to near-colorless HPHT-grown synthetic diamond melee have been produced for the jewelry industry. As a result, the separation of natural from synthetic melee diamonds has become increasingly critical. GIA offers melee diamond screening services using conventional gemological techniques and analytical methods such as photoluminescence and infrared absorption spectroscopy. In September 2016, GIA’s Hong Kong laboratory received 135 melee diamonds for identification service (see figure 1). Of these, 131 were confirmed to be HPHT synthetics and four were natural diamonds. It is interesting to find natural diamonds mixed in HPHT-dominated groups as “contamination.”

	The tested melee were colorless to near-colorless round brilliants, ranging from 0.002 to 0.012 ct. Infrared absorption spectroscopy performed on the 131 HPHT synthetics showed they were generally type IIb with a very weak absorption band at ~2800 cm–1 from trace boron in the diamond lattice. Blue phosphorescence with varying intensity was observed under short-wave UV radiation (225 nm) and could be easily detected in the DiamondView (figure 2). In photoluminescence spectroscopy collected at liquid nitrogen temperature, clear emissions from SiV– at 736.6/736.9 nm were recorded using 633 nm laser excitation, and extremely strong Ni-related emissions at 882/884 nm occurred in all 131 synthetic melee. These features are similar to those observed from known HPHT synthetic diamonds from a few sources in China.

	Figure 2. Phosphorescence in an HPHT-grown synthetic diamond melee.

	The four natural diamonds showed no phosphorescence under short-wave UV radiation. When examined in the DiamondView, they displayed blue fluorescence and very weak phosphorescence. Infrared absorption spectroscopy indicated these stones were type IIa, and no trace boron absorption was recorded. In photoluminescence analysis, no SiV– emission was detected. Surprisingly, all four diamonds showed weak Ni-related emissions at 882/884 nm. Their most notable photoluminescence feature was an extremely broad band centered at ~700 nm, which is usually observed in natural diamonds.

	We would expect to find a small percentage of HPHT synthetics mixed in with natural diamond melee, but on a few occasions we have seen the opposite. As GIA launches the melee sorting service, we anticipate that more melee goods will be submitted for natural vs. synthetic diamond testing. @chapter:15


Publication Year: 2017 Title: Impregnated Amazonite Abstract: Figure 1. In this high-quality translucent amazonite bracelet, the average bead diameter is 12 mm. Photo by Kevin Schumacher.

A type of high-quality translucent blue amazonite feldspar (figure 1) has recently appeared in the jewelry market. Its vivid blue color and unusually high translucency are rarely seen in untreated mineral specimens and rough materials. A rough piece of this material and five beads with different quality grades were obtained for detailed examination at GIA’s Carlsbad laboratory.

To induce the blue-green color in amazonite (KAlSi3O8), the potassium feldspar must contain structurally bound water in addition to lead, and then undergo irradiation (A.M. Hofmeister and G.R. Rossman, “A spectroscopic study of irradiation coloring of amazonite: structurally hydrous, Pb-bearing feldspar,” American Mineralogist, Vol. 70, 1985, pp. 794–804).

FTIR spectroscopy revealed resin impregnation. A thin section cut from the middle of the rough (top of figure 2) was prepared to investigate the depth of impregnation and the origin of the vivid blue color. By performing FTIR in the middle of the section, we confirmed that the impregnation completely penetrated the material. Chemical analysis was obtained with a Thermo Fisher iCAP Q ICP-MS coupled with a New Wave Research UP-213 nm laser ablation unit. A line of 27 ablation spots crossed the whole section. Analysis revealed a microcline feldspar composition with a very minor albite component (figure 2). Pb concentration was irregularly distributed from one rim to the other, eliminating the possibility of Pb diffusion treatment (figure 2, violet data set). The concentration range of Pb was 11.7–44.6 ppma, or 120–432 ppmw. Albite portions contained higher Sr (red data set) and no Rb (blue data set) or Cs (green data set). In contrast, microcline portions contained higher Rb and Cs, and almost no Sr.

Figure 2. The amazonite’s concentration vs. position profile revealed that it was mainly composed of microcline with minor albite. Spots laser-ablated from albite regions contain higher Sr and no Rb and Cs, while spots laser-ablated from microcline regions contain higher Rb and Cs and almost no Sr. The Pb concentration profile is irregularly distributed across the entire thin section (center image, field of view 19.27 mm). Photomicrograph by Jonathan Muyal.
To test their chemical stability, the five beads were immersed in water, reagent alcohol, and then acetone for an hour apiece (figure 3, B–D). The quality of the beads increases gradually from left to right in figure 3. Neither water nor reagent alcohol affected the beads’ appearance (figure 3, B–C). Many whitish fractures became evident on the surface of the smallest, third-largest, and largest beads after immersion in acetone for an hour (figure 3D). Their transparency diminished significantly, and they took on an unsightly mottled appearance. In contrast, the second-smallest and second-largest beads seemed largely unaffected. After 24 hours of immersion in acetone, more whitish fractures became visible in the smallest, third-largest, and largest beads, revealing the true quality of the original material used for impregnation (figure 3E). Very minor whitish fractures were observed in the highest-quality bead (figure 3E, far right). During normal wear, consumers should avoid exposure to solvents that contain large portions of acetone, such as nail polish remover.

Figure 3. Amazonite beads without any post-treatment (A) and after immersion in water for an hour (B), reagent alcohol for an hour (C), acetone for an hour (D), and acetone for 24 hours (E). In all five rows, the bead quality increases gradually from left to right. Photos by Kevin Schumacher. @chapter:6


Publication Year: - Title: Shane McClure Reveals Fascinating Finds from the GIA Lab Abstract: Shane McClure, GIA's director of West Coast identification services, regaled AGS Conclave attendees with some of the unusual cases that have crossed his desk.

                      GIA’s founding father Robert Shipley had a groundbreaking 1934. In addition to launching Gems & Gemology, he established the American Gem Society (AGS) with the intent of promoting professional ethics and continuing education for those in the gem and jewelry industry. In keeping with Shipley’s vision, AGS’ annual Conclave celebrated the society’s 80th year from April 23–26 at San Diego’s Hotel del Coronado, hosting numerous educational seminars, presentations, and networking opportunities. On Thursday, April 24, Shane McClure, GIA’s director of West Coast identification services, presented “A Day in the Life of a Laboratory Gemologist,” exploring the work he has undertaken during his years with the Institute.

McClure compared his role to those of a detective and a forensic scientist, explaining that frequently lab staff must take an unknown material and figure out what it is, while also determining whether the material has been treated. The lab sees specimens that run the spectrum from very rare material to items people find in their own backyards that they hope will prove valuable. McClure considered some of the more unusual cases that he had seen in his years at GIA, discussing interesting identification situations, composite materials, and scams.

Among the identification highlights were a specimen that was sent to the lab as possible opal that turned out to be a piece of bowling ball; a material called  “rainbow calsilica,” reputedly from Mexico, from which the lab removed a piece of a soda bottle; and a sapphire inclusion in a diamond. The latter is now owned by GIA and housed in their reference collection. McClure also referenced a diamond scalpel, that was identified as a CVD grown synthetic diamond, as well as a piece of charcoal that the owner believed might be a black diamond.

According to McClure, composite materials are becoming more common. This may be a result of the rising price of gems coupled with the quantity and low prices required by TV shopping networks for large-scale sales. While the lab most frequently saw such situations in ruby and turquoise, an unusual case involved a pink and green tourmaline held together with plastic.

McClure also discussed specific scams that had come to the attention of the lab during his tenure; for example, so-called “sapphires” and “rubies” that were supposedly worth millions, if not billions of dollars, in some cases using questionable appraisal reports. GIA’s labs saw these cases throughout the 1970s and 80s. He also cited misrepresentations, such as non-identification of treatment. In one instance, the lab received purple opal, supposedly from Kenya or Mexico. Creative testing methods revealed that the opal was from Ethiopia, and had in fact been dyed to appear purple.

McClure closed his presentation with the hot topic of jade nomenclature. He explained how the discovery that another pyroxene mineral called omphacite can be virtually identical in appearance, color, and properties to jadeite, is causing trade experts to reconsider what materials may be defined as “jade.” GIA itself, he noted, has begun to identify some omphacite as “omphacite jade” on reports.

McClure’s experience provides trade members with greater insight into the curiosities lab personnel encounter, and the innovative solutions they implement, during the course of their work. @chapter:24


Publication Year: 2017 Title: Silvery Rutile “Tufts” in Quartz Abstract: Quartz crystals containing stellate tufts of silvery gray rutile were recently discovered in east-central California. Photomicrograph by Nathan Renfro; field of view 9.48 mm.

Recently, author JG discovered a deposit of rock crystal quartz in El Dorado County in east-central California. To date, more than 1,000 quartz crystals have been recovered from a single pocket in this deposit. Almost 50 percent of those crystals contained interesting silvery gray tufts of the titanium dioxide mineral rutile (see above), which was identified using Raman spectroscopy. Rutile in quartz typically occurs as golden needles, but it can occasionally be found as reddish brown, green, or silvery gray needles.

While the cause of the star-like needle arrangement in these particular clusters is not known, it is possible that the gray rutile is overgrown on a core crystal of anatase, which is a polymorph of rutile and might influence the morphology of the cluster. Tufts of golden rutile with a similar morphology have been observed overgrown on blue core crystals of anatase by author NR, which may explain the morphology in this sample; however, it was not possible to confirm this. A similar occurrence of gray rutile overgrowth is known to occur in the material sold as “platinum quartz” from Currelo in Minas Gerais, Brazil, where it is overgrown on the other rutile polymorph, brookite (see E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Vol. 2, Opinio Verlag, Basel, Switzerland, 2005, p. 588).

While production volume of quartz with these silvery rutile inclusions remains uncertain, this deposit has already provided interesting and beautiful additions to the micro-world. @chapter:13


Publication Year: 2015 Title: Green Nephrite Jade Attracts Buyers in Tucson Abstract: Figure 1. For the first time in the history of the Olympics, the medals from the 2008 Beijing Games were mounted with gemstones. The nephrite jade bi, or flat rings, used in the medals were all from China’s Qinghai province. The gold medal was mounted with white nephrite, the color favored by the Chinese, while the silver and the bronze used greenish white and green nephrite, respectively. Courtesy of China Gems Magazine.

The Jade West Group, a leading nephrite jade company in North America for the past 30 years, drew many buyers at their 2015 GJX booth. Prized in Chinese culture for over 5,000 years, nephrite regained its momentum in the domestic Chinese market after the 2008 Beijing Olympics, when it was used in the gold, silver, and bronze medals (figure 1). The Chinese government launched a campaign promoting the significance of nephrite jade in the country’s history. This reignited the love of nephrite among the Chinese people, and the increasing demand and price drove a new surge of jade rush in northern British Columbia (BC).

A tectonic belt running from Alaska through British Columbia to Mexico favored the formation of nephrite. Tectonic and lithological contacts are the predominant ore body controls. BC has more than 50 known nephrite deposits, distributed mainly along tectonic inclusions of country rocks, dikes, and mafic rock layers within serpentinites, or along the contact between serpentinite and the wall rocks. This formation is very similar to other green nephrite occurrences all over the world. Nephrite is found both in situ and as boulders; the Polar Pride boulder, found in BC’s Polar mine, is a well-known example of the latter (figure 2).

Figure 2. Half of the Polar Pride jade boulder discovered in the Polar jade mine. The original boulder weighed 18 tons. Courtesy of Jade West Group.
Nephrite boulders are the products of erosion from the last ice age. They are usually drilled or sawed to test the quality, and only the good-quality material is transported for sale. While some of today’s nephrite is from boulders, primary deposits supply the bulk of BC’s production. This is partially due to the lack of high-quality boulders; however, the growing demand and price for nephrite also make it profitable to mine the primary deposits.

According to Kirk Makepeace, president of Jade West Group, the price of jewelry-grade jade from BC (figure 3) experienced at least a tenfold increase from a decade ago. Before 2008, top-quality nephrite from BC sold for about $20 a kilo; equivalent stones now range from $200 to $2,000 a kilo.

Figure 3. This strand of 41 nephrite beads is comprised of material from British Columbia’s Polar Mine. Photo by Robert Weldon; courtesy of Jade West Group.
The annual production of BC nephrite jade is about 400 tons. Most of the production comes from four active mines; together, they produce about three-quarters of the world’s high-quality green nephrite. Of these four, Jade West operates the Polar, Ogden, and Kutcho Jade mines. Jade West also deals with material from Wyoming and Siberia. Over the last 10 years, approximately 90% of the company’s BC production was exported to mainland China; the remaining 10% was sent to Taiwan, Vietnam, and Thailand.

Figure 4. This Canadian Jade Fish Hook pendant features a piece of nephrite from the
Kutcho Mine. This is one of the styles Jade West has customized for the North American
market. Photo by Robert Weldon, courtesy of Jade West Group.
Jade West sends almost all of its rough nephrite to Guangdong for carving and jewelry manufacturing, with designs customized for different markets (figure 4). In addition to traditional carvings and jewelry, there is demand from Southeast Asian countries for giant Buddha statues and from Western countries for home decorations. This demand leads Mr. Makepeace to be very optimistic about the future availability of BC nephrite. @chapter:37


Publication Year: 2014 Title: Gem-Quality Cr-Rich Kyanite from India Abstract: Figure 1. These gem-quality kyanites (0.99–6.17 ct) were reportedly mined in the eastern Indian state of Odisha. Photo by Gagan Choudhary.

In 2009, one of the contributors had the opportunity to see small lots of greenish blue to bluish green Cr-rich kyanite in Jaipur, reportedly mined from the eastern Indian state of Odisha (formerly Orissa). Most of the cabochons and faceted gems, ranging in size up to 25 ct, were highly included. In 2013, this Cr-rich kyanite from Odisha was again available in Jaipur, this time with very few or no eye-visible inclusions (figure 1). Although a few specimens contained numerous black inclusions, most of the stones lacked these features and had a more desirable uniform greenish blue to bluish green color, making them suitable for jewelry mounting.

Standard gemological properties were measured for one cabochon and two faceted samples (0.99–6.17 ct). The cabochon was chosen for its striking black eye-visible inclusions. The three samples showed an RI of 1.714–1.730 (spot RI of 1.73 for the cabochon) with birefringence of 0.016 and a biaxial positive optic sign, and a hydrostatic SG of 3.68–3.70. Moderate to strong trichroism was observed, with pleochroic colors of greenish blue, bluish green, and pale green. Under a desk-model spectroscope, all three displayed fine lines in the red region with absorption bands in the yellow-orange and blue regions. The samples appeared strong red under the Chelsea filter and were inert to both long- and short-wave UV. These properties were consistent with those reported for kyanite.

Figure 2. These kyanites display striking black metallic crystals of ilmenite; note the striated surface and the few colorless crystals of quartz. Photomicrograph by Gagan Choudhary; magnified 64×.
Examined under the microscope, the black inclusions in the cabochon appeared to be clusters of black grains with striated surfaces and metallic luster (figure 2); some appeared iridescent in reflected light, while others displayed frosted surfaces. Raman and SEM analysis identified these black grains as ilmenite. In addition, numerous colorless sub-rounded crystals of quartz, feldspar, and zircon were observed; the latter usually occurred in clusters, with stress cracks around them (figure 3). These samples also displayed cleavage planes in two directions and fine fissures, a characteristic usually seen in kyanites.

Figure 3. Clusters of zircon crystals associated with stress cracks were another common feature in these kyanites. Photomicrograph by Gagan Choudhary; magnified 80×.

Figure 4. The UV-Vis-NIR spectrum in the 300–800 nm region showed broad absorption band between 500 and 700 nm (assigned to Fe2+-Ti4+ charge transfer), along with twin peaks at approximately 690 and 708 nm (associated with Cr3+). In addition, numerous Fe3+-related peaks were present in the 350–470 nm region.
UV-Vis-NIR spectroscopy in the 300–800 nm region (figure 4) showed broad absorption bands between 500 and 700 nm, with a slight shift in the center position from about 585 nm (green direction) to 610 nm (blue direction). Also present were distinct peaks at approximately 370, 380, 417, 432, 446, 690, and 708 nm. The latter two peaks are associated with Cr3+ and the rest to Fe3+. The broad absorption band is attributed to the Fe2+-Ti4+ charge transfer (see G. Bosshart et al., “Blue colour-changing kyanite from East Africa,” Journal of Gemmology, Vol. 18, No. 3, pp. 205–212).

Gem-quality kyanite is already known from Nepal, Brazil, Kenya, Tanzania, and Madagascar (the latter material being Cr-rich as well). Now India can be added to this list, with attractive greenish blue to bluish green colors. The production and supply of this kyanite are still unknown. @chapter:4


Publication Year: 2014 Title: Gem Session at 2014 GSA Meeting Abstract: Visitors to GIA’s booth at the 2014 GSA conference spoke with representatives, including Dr. James Shigley, left, to learn about GIA, gemology education programs, and career opportunities. Photo by Cathy Jonathan/GIA.

              A full-day session on gem materials was held Oct. 20, 2014, in conjunction with the annual meeting of the Geological Society of America (GSA) in Vancouver.

The morning presentations focused mainly on diamonds. Thomas Stachel (University of Alberta) summarized work to constrain the geological conditions of diamond formation. It is thought to have formed in the mantle from an oxidized carbonate-bearing fluid with high carbon and low nitrogen concentrations. Eloïse Gaillou (Natural History Museum of Los Angeles County) discussed pink diamonds whose color originates from narrow lamellae created by plastic deformation parallel to the octahedral growth planes. These lamellae contain a high density of luminescent defects along with localized strain. As a result of plastic deformation in the mantle, these diamonds accommodate stress along the lamellae by mechanical twinning. The unidentified optical defects responsible for the pink coloration are also created by this deformation. Richard Wirth (GeoForschungsZentrum) described the use of a transmission electron microscope with a focused ion beam to characterize microstructures in materials. Blue color in quartz is caused by Rayleigh scattering from submicron- and nanometer-sized inclusions of mica, ilmenite, and rutile. The black color of carbonado diamond results from its polycrystalline nature and partially open grain boundaries that cause internal total reflection of light. Cloud-like inclusions in Madagascar sapphires are due to nanocrystalline titanium-rich oxide inclusions. Wuyi Wang (GIA) discussed the use of carbon isotope analysis to help distinguish natural diamonds from CVD-grown synthetic diamonds. He found no overlap in isotope composition between them, but within the synthetic diamonds there was variation between manufacturers and even from the same manufacturer. Karen Smit (GIA) described interesting features of diamond crystals from Marange, Zimbabwe, which display both cuboid and octahedral growth sectors and distinctive center-cross patterns (often highlighted by graphite-particle clouds). Mike Breeding (GIA) reviewed the properties of certain treated-color diamonds. Electron irradiation yields green colors in diamonds with higher nitrogen content, and blue colors in diamonds with lower amounts of nitrogen. Characterization of their optical defects provides a means of distinguishing them from natural-color diamonds. Troy Ardon (GIA) characterized some optical defects in hydrogen-rich diamonds from Zimbabwe. Spectral features associated with certain defects could be correlated with noticeable clouds in these diamonds. Robert Luth (University of Alberta) discussed a model of diamond formation in the mantle. He suggested that it takes place as carbon-hydrogen-oxygen (CHO) fluids rise in the lithosphere during isobaric cooling, or combined cooling and decomposition. This model helps explain a number of observations regarding the geologic occurrence of diamonds. Mandy Krebs (University of Alberta) discussed size frequency distribution as a predictive tool for macro-diamond grade at Canada’s Ekati mine. She found that Ekati diamonds of different size fractions display broadly similar nitrogen and carbon-13 isotope compositions. Mederic Palot (University of Alberta) studied diamonds from the Kankan deposit in Guinea that are believed to have formed at great depths (300 km in the mantle). Characterization of nitrogen and carbon isotopes indicates rapid ascent from the mantle to shallower depths. Charles Kosman (University of British Columbia) studied the chemical composition of mineral inclusions in alluvial diamonds from the Kasai area of Congo. These diamonds originated from the kimberlites around Lucapa in neighboring Angola, which contain a significant proportion (~ 20%) of eclogitic diamonds.

Dona Dirlam (right) talks with Dr. Eloïse Gaillou at the GIA booth. Photo by Cathy Jonathan/GIA.
The afternoon session covered a range of topics. Lee Groat (University of British Columbia) reviewed Canadian gem minerals. In addition to diamond, the country is an important source of nephrite jade, ammolite, and amethyst. Recent discoveries of ruby, sapphire, spinel, and emerald also show promise. David Newton (University of British Columbia) analyzed peridotite and pyroxenite xenoliths from the Muskox kimberlite in northern Canada to better understand the rock types in the underlying mantle. Howard Coopersmith (Fort Collins, Colorado) described a placer deposit at Mount Carmel in Israel that has yielded diamond, ruby, sapphire, and natural moissanite crystals and fragments that appear to have originated from different igneous and metamorphic source rocks. Aaron Palke (GIA) presented a trace-element study of demantoid garnet as the basis for distinguishing this important gem material from different geologic and geographic sources. Cigdem Lule (Glenview, Illinois) discussed the need for a more systematic approach to gem nomenclature, which is often determined by jewelry trade practices, as opposed to the more rigorous procedure used for assigning new mineral names. Nancy McMillan (New Mexico State University) presented a multivariate chemical analysis of tourmaline, a mineral that can be an exceptional provenance indicator in detrital sediments. This analysis has proven successful in assigning tourmaline samples to different geologic environments. David Turner (University of British Columbia) conducted a study of sapphires and associated minerals from the marble-hosted Beluga occurrence in northern Canada by hyperspectral imaging over the 550–2500 nm range. This technique could be useful in the field for analyzing rock samples and in airborne surveys over terrain with good rock exposures. Philippe Belley (University of British Columbia) studied blue calcite skarn deposits in Ontario and Quebec. Their geologic setting and low iron content make them potential sources of grossular garnet and other gem minerals. J.N. Das (Geological Survey of India) reviewed the exploration and mining of diamonds and colored gemstones throughout India. Andrew Fagan (University of British Columbia) described the Aappaluttoq ruby and pink sapphire deposit in Greenland. Based on field studies, it appears to be the world’s largest geologically defined gem corundum deposit, with an estimated 400 million carats of material within 65 meters of the surface. Commercial mining is expected to begin in 2015. Sytle Antao (University of Calgary) studied optical anisotropy in cubic garnets, which has been recognized for more than a century but remains incompletely understood. X-ray diffraction study of several anisotropic samples revealed they contain two or three cubic phases with slightly different structural parameters. The intergrowth of these phases on a nano-domain scale produces the strain-induced optical anisotropy. Barbara Dutrow (Louisiana State University) discussed how tourmaline, an important accessory mineral in many geologic environments, can be used to help locate gem deposits.

In the separate poster session, Ellen Svadlenak (Oregon State University) and co-authors used electron microprobe analysis to study variations in the trace elements in emeralds from Muzo, Colombia. Lauren Forbes (Western Washington University) and co-authors analyzed emeralds from four different Muzo mines using SEM-CL (cathodoluminescence) along with LA-ICP-MS to better understand the chemical and physical conditions for their growth. All emeralds tested showed a strong red luminescence. The researchers concluded that Muzo emeralds are compositionally unique. Gena Philibert-Ortega (Murrieta, California) and co-authors described the scientific influence of James Sowerby’s rare five-volume British Mineralogy in the early 19th century. Elise Skalwold (Cornell University) and coauthors reviewed their research on a highly unusual blue inclusion in a diamond. While it was identified as olivine, the reason for the blue color remains a mystery.

An overview of the gem research session from the 2014 GSA meeting is available at https://gsa.confex.com/gsa/2014AM/webprogram/Session35272.html. @chapter:23


Publication Year: - Title: JCK 2016: Trying to Jumpstart Millennial Demand Abstract: Buying at the June JCK Show in Las Vegas was at the lower end of expectations, according to exhibitors. Photo by Russell Shor/GIA

	Business at the JCK Show in Las Vegas fell at the low end of expectations as retailers continue to remain cautious about the direction of the U.S. economy and struggle to retool their sales efforts to appeal to consumers beset by stagnant incomes and appeals from competing products.

	Buying Segments

	Designers at the upscale Luxury and Couture shows reported decent demand, but the trend continued away from obvious bling toward pieces with distinctive looks using small diamonds and gemstones.

	Demand for commercial jewelry and loose diamonds was very spotty. Buyers tended to order the minimum they believed they would need before the fall season. Jewelry and diamond demand was better in the upper segment of more than $20,000 and in the lower-priced market under $2,500.

	Demand for loose colored stones at the accompanying American Gem Trade Association show was very slow, but better in finished jewelry pieces as designers wanted to create larger looks with stones such as aquamarine, amethyst, chalcedony, opals and various types of garnets.

	Design Trends

	A number of designers offered convertible pieces – pendants that could be detached as a ring or multi-pieced rings that could be worn as separate items. There were also ear pendants of opaque stones and very fine gold or sterling silver strands. Items made with larger stones like opal, accented by diamond pavé or unusual gemstones, invite retailers to talk about them with their customers.

	Loose Diamonds

	Dealers said profitability has improved since last fall, but sales remain sluggish. As one high-end diamond dealer put it: “We’ve done OK, but every year the definition of OK seems to be getting a little lower. “

	At the high end, demand for better qualities larger than 5 carats was there, but seller competition was keen.

	“Consumers in that price range still have good disposable incomes and many are veteran jewelry buyers,” said one major dealer. “And there is still demand at the lower price level, but competition there is extremely intense and retailers are squeezing harder than ever for terms and memo, so that makes it difficult to recover.”

	The middle, he said, is the biggest challenge. “The squeeze middle class consumers face today is well-publicized. We, as an industry, have to figure out how to sell to them again.”

	Marketing Initiatives

	Indeed, marketing to the millennial generation was on everybody’s mind, even though the difficulties of the middle class extend well beyond that age range.

	There were a number of sales initiatives and seminars announced at the show to try and help retailers, jewelry manufacturers and gem dealers connect with that generation. The most significant was an estimated $12 million program developed by the Diamond Producers Association (DPA), a group formed a year ago from the world’s seven largest diamond mining companies.

	The campaign, which will be presented in various social media and TV outlets, has the slogan “Real is rare. Real is a diamond.” The campaign, showing young couples in clubs and in resorts, continues to be relationship-oriented similar to the De Beers “Forever” advertising of past years, but is not aimed specifically at engagement or anniversary jewelry as those were.

	“Marketing diamonds is much more complex today, so you cannot employ the same practices we used 20 years ago,” said Stephen Lussier, DPA chairman and CEO of De Beers’ Forevermark.

	David Lamb, a marketing consultant for DPA, said this generation wants real connections, but are much less about formality and traditional rules than previous generations. The purpose of this campaign “is to get them think that a diamond is the perfect symbol of a real connection,” he noted.

	The diamond trade generally reacted positively to the campaign and slogan, particularly because it addressed growing competition from synthetic diamond producers. These man-made diamonds appeared in a number of designer lines offered at the Vegas shows and a number of wholesalers were offering both colorless and fancy colored synthetics.

	The well-publicized start-up Diamond Foundry was test-marketing diamonds through four companies exhibiting at the show and a spokesman for the company noted that it has begun commercial production. @chapter:36


Publication Year: 2022 Title: Calcite Found on the Surface of a Saltwater “Nacreous” Pearl Abstract: Figure 1. A cream-colored button-shaped loose pearl weighing 2.32 ct, submitted for identification. Photo by Tony Leung.
The Hong Kong laboratory recently examined a loose pearl weighing 2.32 ct and measuring 8.45 × 7.27 × 5.36 mm (figure 1). Externally, the cream-colored pearl did not look out of the ordinary and exhibited a soft luster with a relatively clean surface. Examination through a binocular microscope revealed typical overlapping platelets, pits, and scratches. No coating, surface working, or other indications of treatment were observed (figure 2).

Figure 2. The pearl exhibited overlapping surface platelets typically found in nacreous pearls. Photomicrograph by Nick Chan; field of view 1.10 mm.

Figure 3. RTX examination revealed a clear boundary running across the pearl as well as structures associated with natural formation. Images by Cheryl Ying Wai Au.
Real-time microradiography (RTX) revealed a distinct boundary with twin growth structures consisting of normal growth layers that followed the shape of the pearl (figure 3). No structural characteristics of any known type of cultured pearl were observed, so the pearl was identified as a natural pearl. Energy-dispersive X-ray fluorescence analysis showed high levels of strontium and no traces of manganese. This, together with its lack of visible fluorescence to X-ray luminescence, confirmed its saltwater origin.

Figure 4. Raman spectra of three spots on the pearl’s surface exhibit main peaks at 156, 282, 712, and 1087 cm–1 that are diagnostic of calcite.
Despite the typical saltwater nacreous pearl surface appearance, Raman analysis on three random spots with 514 nm laser excitation revealed that the pearl’s platelet surface was composed of calcite rather than aragonite, with peaks at 156, 282, 712, 1087, and 1437 cm–1 (figure 4) (J. Urmos et al., “Characterization of some biogenic carbonates with Raman spectroscopy,” American Mineralogist, Vol. 76, 1991, pp. 641–646).
Nacreous pearls are typically composed of small polygonal tablets of aragonite arranged in laminar layers (L. Addadi and S. Weiner, “A pavement of pearl,” Nature, Vol. 389, 1997, pp. 912–915). Up until the examination of this specimen, Raman analysis on submitted pearls and research samples exhibiting overlapping platelet layers has always shown a mineral composition of aragonite. Calcite is usually found in the form of mosaic or cellular patterns on the surface of some types of pearls, or in the prismatic internal layers. This is the first time GIA has encountered a “nacreous-looking” pearl showing calcite when tested in different positions on its surface, which is unique and certainly worthy of note. @chapter:14


Publication Year: 2017 Title: “Boldly Go” with a Southwest-Inspired Starship Enterprise Abstract: This handmade piece fuses Southwestern style and its characteristic inlay techniques with a science fiction icon: the Starship Enterprise from Star Trek. Photo by Kevin Schumacher; courtesy David R. Freedland Jr. Designs.

	At the Pueblo (Riverpark Inn) show, David Freedland (David R. Freedland Jr. Designs, Tucson) showed us some unusual pieces that stood out at his booth. Normally, you expect Southwest-style jewelry to embrace nature or Native American influences for pieces featuring detailed inlays of Arizona turquoise and other materials. Although Freedland had these in abundance, what really caught our eye was this handmade, sterling-silver rendition of the Starship Enterprise from the cult science fiction television series Star Trek. The piece measures 6.5 cm in length and stands 4.5 cm high. It rests on a sterling silver stand inlaid with Arizona turquoise (see above).

	The iconic starship’s saucer section is also inlaid with Arizona turquoise and a concentric band of purple spiny oyster centered on a lab-grown white opal representing the bridge. Other oval lab-grown opal cabochons grace the ends of the engine nacelles, and a turquoise cabochon represents the ship’s shuttle bay. The starship portion has a loop and can be detached and worn as a pendant, if desired. Freedland also has another handmade starship available: the “Reliant” from the 1982 motion picture Star Trek II: The Wrath of Khan along with an array of cyberpunk—or steampunk—ray guns that are redolent of classic U.S. science fiction films of the 1950s.

	Freedland told us there’s no other reason behind the considerable time and effort required to hand fabricate these unique pieces except that he’s always liked the idea of space and the unknown—“what’s out there,” as he says. And he thought they would be a lot of fun to make. We hope these designs live long and prosper. @chapter:16


Publication Year: - Title: GIA Gem Project Corundum Abstract: Corundums (ruby and sapphires) occur in all colors of the spectrum, and have remained popular gemstones hi ancient times to the present day. Photo by Robert Weldon/GIA

Ruby and sapphire (usually blue, but also in every other color) have been the most important colored gemstones for several thousand years. Originating historically in southeast and central Asia, and more recently in eastern Africa, these colored varieties of the mineral corundum have been much sought as gems because of their rarity, color and durability. Gem corundum can display asterism and chatoyancy due to the presence of oriented mineral inclusions, and in some cases, a change of color when viewed under different light sources. @chapter:8


Publication Year: 2016 Title: Red Cordierite from Madagascar Abstract: Figure 1. These three gems, weighing (from left) 4.17, 1.28, and 1.28 ct, were fashioned from the same piece of cordierite rough; red is a new color for this gem. The specimen originated from a recently explored deposit in southeast Madagascar. Photo by Benjamin Rondeau.

	At the Mineral Expo show in Paris in early December 2015, we procured a large piece of dark red cobbed rough presented as cordierite. This would be the first documented occurrence of red cordierite. The slightly fractured 3 cm rough offered a magnificent deep red color when examined using transmitted light from a Maglite illuminator. The identity of the rough as cordierite was confirmed using Fourier-transform Raman (FTR) spectrometry. The spectrum obtained showed excellent agreement with a reference spectrum for cordierite from Madagascar in the RRUFF database (http://rruff.info).

	Author TP confirmed that the piece we examined was from the Iakora district, Fianarantsoa province, in southeast Madagascar. Cordierite has long been known in this general area (A. Lacroix, Minéralogie de Madagascar, A. Challamel, Paris, 1922). There is no mechanized mining. According to a miner’s sketch obtained locally by one of the authors, red cordierite occurs in a “vein” (probably a layer) associated with orange and blue cordierite, parallel to other layers containing kornerupine or blue spinel. The cordierite vein is about 1.50 m thick and wide and is apparently contained in a kornerupine layer. Cordierite is usually found in a metamorphic environment, but the layered appearance, with each band containing specific minerals in thicknesses of about 1 m, is reminiscent of metasomatic deposits. The association of cordierite with kornerupine and spinel is already known; blue gem-quality cordierite is found in such a metasomatic reaction zone in Kenya (C. Simonet, pers. comm., 2015).

	To determine the material’s gemological properties, three stones were fashioned by Jacques Le Quéré (Auray, France): a 2.69 ct modified rectangle; a 1.28 ct flat cabochon, cut to obtain a lighter color; and a 4.17 ct parallelepiped, faceted based on the optical directions to best show its trichroism (figure 1). The RIs, measured with a Rayner LED sodium-equivalent lamp, ranged from 1.527 to 1.541 (nx = 1.528–1.530, ny = 1.532–1.533, and nz = 1.538–1.540). Interestingly, this crystal presented a biaxial positive character, whereas gem cordierite is typically biaxial negative.

	The trichroism was very strong, as expected with cordierite. With a standard dichroscope, the colors ranged from deep red to orange to grayish brown with a hint of blue or purple (figure 2), this last color becoming black at a thickness of about 1 cm (figure 3). Hydrostatic SG measured 2.548–2.554. These properties are consistent with cordierite, though SG was at the lower end of the range.

Figure 2. Pleochroism of the oval cabochon observed in polarized light in the two orthogonal directions. On this thinner sample (about 3 mm thick), the desaturated grayish brown color with a hint of blue or purple is best observed. The stone measures 9.85 × 6.75 mm. Photos by Emmanuel Fritsch.

Figure 3. Trichroism of the 9.45 × 6.95 × 5.28 mm cordierite parallelepiped observed in polarized light in the three orthogonal directions to represent the three “extreme” colors of the material’s pleochroism: deep red, black (both seen with a thickness of 9.45 mm), and orange (seen with a thickness of 6.95 mm). Photos by Emmanuel Fritsch.

	As the rough was sawed, we noticed that the vivid red transparent color of the thick crystal turned to orange with reduced thickness. This is the definition of dichromatism, also known in gemology as the Usambara effect, a variation of hue that is affected by the optical path length.

	The UV-visible absorption spectrum was measured on a Unicam UV4. When the material was a few millimeters to a centimeter thick, in the direction where red is observed there is an extremely strong absorption in the violet and blue areas; this band leads to the red color. The absorption decreases abruptly from about 550 to 685 nm, with only a weak broad band from about 710 to 800 nm. This leaves a steep transmission window in the red, which is consistent with the color observed. The shape of the absorption and a rapid decrease in the orange-yellow also explains the Usambara effect. Through a few millimeters, the perceived color is orange; through a centimeter or more, it is deep red. @chapter:5


Publication Year: 2013 Title: Boron Carbide: A New Imitation of Black Diamond Abstract: Figure 1. This 1.04 ct black submetallic round brilliant, initially represented as diamond, was identified as boron carbide. Photo by Gagan Choudhary.

              As black diamond has gained popularity in the past few years, so have aggregates of black synthetic moissanite and crystalline silicon (Spring 2011 Lab Notes, pp. 54–55). One specimen received by the Gem Testing Laboratory in Jaipur, a 1.04 ct black submetallic round brilliant (figure 1), appeared to be synthetic black moissanite but proved otherwise. The specimen was presented to the owner as a diamond.

	Figure 2. Under reflected light, the boron carbide specimen displayed a dense, fine granular structure typically associated with aggregates such as ceramics. Photomicrograph by Gagan Choudhary; magnified 48×.
Due to the prevalence of black synthetic moissanite in the marketplace and gem laboratories, we immediately checked for the typical aggregate structure under the microscope. Although a granular pattern was distinctly visible in reflected light (figure 2), it was much denser and finer than the kind usually seen in black synthetic moissanite. This raised uncertainty, so additional gemological tests were performed. The specimen had an over-the-limit RI, an SG of 2.43, and a hardness above 9 on the Mohs scale. The low SG value ruled out the possibility of synthetic moissanite (3.22), but otherwise offered no clues as to the specimen’s identity.

	Figure 3. The boron carbide’s Raman spectrum showed major peaks at approximately 260, 320, 480, 532, 720, and 1088 cm–1.
Qualitative EDXRF analysis revealed Fe, with traces of Si and K. Raman spectra taken from several points using 532 nm laser excitation showed major peaks at approximately 260, 320, 480, 532, 720, and 1088 cm–1, with smaller peaks at about 800, 824, 874, 967, and 998 cm–1 (figure 3). This combination of features did not match anything in our database, but an extensive literature search revealed an exact match with the Raman spectra of boron carbide (V. Domnich et al., “Boron carbide: Structure, properties, and stability under stress,” Journal of the American Ceramic Society, Vol. 94, No. 11, 2011, pp. 3605–3628, http://dx.doi.org/10.1111/j.1551-2916.2011.04865.x).

Boron carbide is an advanced ceramic material with high hardness, low density, thermal stability, and extreme abrasion resistance, making it suitable for nuclear, military, and aerospace applications. The material is typically produced by reacting and fusing carbon with boric oxide (B2O3) in an electric arc furnace, followed by a sintering process of hot pressing in graphite dies under a vacuum or argon atmosphere at temperatures of 1900–2200°C and pressures of 0.02–0.04 GPa for 15–45 minutes (Singhal and Singh, “Sintering of boron carbide under high pressures and temperatures,” Indian Journal of Engineering and Materials Sciences, Vol. 13, April 2006, pp. 129–134).

Although boron carbide is common in engineering and materials science—used as scratch-resistant coating and plating in tank armor, bulletproof vests, and padlocks—this was our first encounter with it as a diamond simulant. Our literature search (by Mr. Sandeep Vijay, a staff gemologist) did not reveal any gemological uses of this ceramic product. Distinguishing boron carbide from black diamond or synthetic moissanite was straightforward on the basis of SG, but Raman spectra and reference data were needed for identification. The possibility of market penetration cannot be ruled out. @chapter:32


Publication Year: - Title: Books: Rings – Jewelry of Power, Love and Loyalty Abstract: By Diana Scarisbrick, 384 pp., illus., publ. by Thames and Hudson, London, 2014, $34.95.

                      If you’ve ever uttered the words, “I think I’ll wait till it comes out in paperback,” your ship just came in. I’ve said it myself, numerous times, and then forgotten all about whatever book I was waiting for. Not this time.

Originally published as a hardcover in 2007, Rings: Jewelry of Power, Love and Loyalty is the real deal. It is brilliantly photographed, meticulously researched, and engagingly readable, with a high-quality paperback binding, sewn pages, and a double foldout cover. At $34.95, you can’t afford not to own this treasure.

Perhaps my favorite feature of this book is simply that it contains multiple images of many of the subjects. How often do you see the top view of a ring and wonder what a side detail looks like? Or you might have a perfectly acceptable perspective view, yet the text describes an engraving on the inside of the band that is not shown in the image. Kudos to Scarisbrick and the photographer for taking the time to include these creative angles. What a luxury.

The heart of the book is the Benjamin Zucker Family Collection, accompanied by pieces from the Walters Art Museum in Baltimore, the Museum of Fine Arts in Boston, Rosenborg Castle in Copenhagen, London’s Freud Museum, the Cartier Collection, and a host of private collections.

The organization of information in Rings is a treat. It is arranged into eight thematic chapters, each explored chronologically from ancient times to the present. With this format, you can see the evolution of certain types of rings, and how art, fashion, politics, and social norms exerted their influences. Starting with 50 pages of signets in the first chapter, all of the sections provide insightful ways to associate and characterize the groupings of rings.

The remaining chapters parse the vast oeuvre of rings into what might be considered sociological subdivisions, such as “Love, Marriage, and Friendship Rings,” “Rings Associated with Illustrious People and Great Events,” “Decorative Rings,” and so on. I am fascinated to see how the ring, a relatively small item, can open up insights to so many different time periods and how the popularity of different types of rings waxed and waned.

Adding to the depth of information in each chapter is the use of drawings and paintings from various periods. Scholarly but not stuffy, the background text fleshes out the humanity behind the rings and adds insights about the people and the times. Equally impressive is the technical mastery of countless, mostly anonymous, jewelry makers. We see examples that may have been solo efforts, as well as numerous collaborations between designers, goldsmiths, lapidaries, stone setters, enamelists, and polishers. All come together to create a lasting, wearable work of art, the perennially popular ring. @chapter:16


Publication Year: - Title: 80 Years of Gems & Gemology Abstract: The journal had humble beginnings. Robert M. Shipley, founder of GIA and the publication, produced the ﬁrst issues out of his home. He and his son, Robert Jr., wrote many of the articles, while Shipley’s wife, Beatrice, was the business administrator. Shipley’s vision of a publication “to increase the gem merchant’s knowledge and ability” evolved and flourished. Eminent gemologists such as Robert Crowningshield and Edward Gübelin wrote articles about industry milestones. Richard T. Liddicoat assumed the roles of editor of Gems & Gemology (G&G) and president of GIA in 1952, continuing in the pioneering tradition of his predecessor. Now 80 years since its conception, G&G continues its legacy as a groundbreaking, award-winning research journal.

Over these eight decades, G&G has been a critical resource for the gem and jewelry industry. Groundbreaking articles on diamond grading appeared as early as the 1940s. Through the Lab Notes section, GIA gemologists reported on the latest treatments and synthetics, which helped to protect the trade and the public.

Clarity enhancement of emeralds and diamonds. High-tech color enhancement of rubies and sapphires. Synthetic rubies, emeralds, sapphires and—perhaps the greatest challenge—synthetic diamonds. All have been explained through the pages of G&G.

At the same time, the journal has introduced to the world new gem materials such as moissanite; explored historic and new gem deposits from Colombia to Mozambique; and reported on rapid developments such as the emergence of China’s cultured pearl industry and diamond mining in Canada.

“For 80 years, G&G has been one of the principal professional journals for information on gem materials of all kinds. Its contents reveal the evolution of the science of gemology,” said Dr. James Shigley, GIA Distinguished Research Fellow. G&G continues to evolve under the editorship of Duncan Pay. While the journal will retain its scientific rigor, Pay’s vision is to reach a broader audience and further integrate its groundbreaking research into GIA education.

“G&G is backed by GIA’s laboratory, giving us unmatched resources to investigate the important issues of the day. This makes it a unique vehicle for advancing the study of gemology and for educating our students and the trade professionals,” noted Pay.

All 80 years of G&G are available for free download at www.gia.edu, thus broadening its reach around the globe. Gem and jewelry professionals can easily access a library of diverse and relevant articles. We also asked the journal’s editor and key contributors to pick ten landmark articles, and their selections are fascinating and illuminating. View the landmark articles here.

If history is a guide, the next 80 years promise to be even brighter than the first. @chapter:29


Publication Year: - Title: Video Feature: Gem Mining in Cambodia Abstract: See how locals in Pailin, a province in western Cambodia near the Thai border, mine for small sapphires, rubies, zircon, garnet, and sometimes gold.

	Sapphire and Ruby Mining

	GIA field gemologist Vincent Pardieu joins a small team of miners as they wash the ground for sapphire and ruby at a secondary deposit in Pailin.

	River Mining in Pailin, Cambodia

	Pardieu visits one of two main rivers in Cambodia where local miners collect garnet, zircon, ruby, sapphire, and sometimes gold from the sand. Many of them mine the river during the dry season to earn additional income. @chapter:25


Publication Year: 1988 Title: Spring 1988 G&G Lab Notes Abstract: Synthetic Alexandrite
Artistically Stained Chalcedony
Clinohumite
Cyclotron-Treated Diamond
Damaged Diamond
Banded Lapis Lazuli
Early "Japanese" Pearls
Natural Pearl and Diamond Tiara
Color Zoned Sapphire
Sapphire with Needles
Tourmaline from Nepal
Imitation Turquoise with "Veins" and Pyrite

To view the full section, download the PDF above. @chapter:17


Publication Year: 2000 Title: Synthetic Gem Materials and Simulants in the 1990s Abstract: The 1990s witnessed important developments in the commercial viability of gem-quality synthetic diamonds. Improvements in, and new applications for, existing synthesis processes in the production of colored stones such as ruby, sapphire, emerald, quartz, and alexandrite have had an impact as well. The development and commercialization of a variety of new synthetics and simulants, such as synthetic moissanite and flux-grown synthetic spinel, also played an important role in shaping the past decade for the gem and jewelry industry. @chapter:17


Publication Year: 2012 Title: Brazil’s Emerald Industry Abstract: Figure 1. Open-pit mining at Belmont is conducted on a large scale. Trucks are constantly being filled with ore to be taken to the processing plant. Photo by A. Lucas.

              Since the 1970s, Brazil has been a consistent source of emerald. This is especially true today, with steady production from the Itabira/Nova Era belt in the gemrich state of Minas Gerais.

Along with successes there have been challenges for the Brazilian emerald industry. Increasingly strict environmental regulations and higher labor costs have made production more expensive. Mining companies have had disagreements with land owners, and there have been legal issues with the independent miners known as garimpeiros. Another challenging issue facing the mining, cutting, and trading sectors is the rapid rise of the Brazilian real against the U.S. dollar.

While Brazilian emeralds were not traditionally known for their quality, this perception has been changing. Stones from the Itabira/Nova Era belt reportedly sell for up to $30,000 per carat. Nova Era tends to produce clean faceted stones, which are highly popular with jewelry manufacturers. The emeralds’ fine color and good transparency make this material highly sought after in the marketplace.

	Belmont, Minas Gerais
The Belmont property was originally a cattle ranch and remains one today. But since 1978, Belmont has also operated a well-known emerald mine. It is managed by Marcelo Ribeiro, whose grandfather discovered emeralds on the ranch by accident. It began as an open-pit operation (figure 1). Bulldozers remove the weathered emerald-bearing material and transport it to a processing area for washing and sorting.

After two decades of open-pit mining, Belmont added underground operations in 1998. Miners were lowered into a 75 m vertical shaft, from which they dug side tunnels by hand or using explosives, removing the schist and bringing it back up the shaft.

An elevator carried five personnel as well as mined material in and out of the underground mine. During this contributor’s visit to Belmont in 2004, the company estimated another 10–15 years of production remained in the open-pit mine. Now they believe the open-pit area may have a much longer life span.

Since 2004, Belmont has expanded the underground operation into a ramp-style underground mine where trucks drive directly into the workings. The emeraldbearing schist is broken up by explosives, and front loaders empty it onto trucks to be taken to the processing plant.

Optical sorting has replaced hand picking of the emeralds. These devices are faster and have a higher recovery rate, while eliminating the possibility of theft. The optical sorting instrument used by Belmont can be cus tomized to identify a variety of minerals. A charge-coupled device (CCD) camera recognizes the emeralds in the schist by color, triggering an air blast that moves them to a conveyor belt (figure 2).

Figure 2. A conveyer belt brings ore into the optical sorter at Belmont for the CCD cameras to scan. Photo by Eric Welch.
Belmont has processed 70,000 tonnes of ore annually for the last three years, recovering 250,000 grams of rough emerald per year. That works out to 1 g of emerald per 0.28 tonnes of processed ore. But to obtain the 70,000 tonnes of emerald-bearing ore, Belmont must first remove 350,000 tonnes of overburden. While the average production of emerald-bearing schist is 6,000 tonnes per month, the output is higher during the dry season and lower during the rainy season that runs from September through February. Eighty percent of the production is from open-pit mining, 20% from the underground operation. This is because Belmont’s processing plant is designed primarily for the weathered material from the open-pit operation. The processing plant is being expanded to better handle the harder emerald-bearing schist. By the end of 2012, Belmont expects underground mining to account for half of the output.

On average, 1 g of rough emerald produces 1ct of faceted emerald, or 250,000 carats per year. The typical size range of the rough is 2–20 mm or 0.2–20 g. Belmont is known for high-quality rough that allows cutters to consistently produce calibrated 1–5 mm rounds, as well as 1–10 ct center stones for jewelry manufacturers.

The rough sorting facility is located in the nearby town of Itabira. Belmont sorts the rough for its manufacturing customers into 15 qualities and five different size ranges, for a total of 75 rough categories. About 80% of the rough sold by Belmont is cut in India.

The mine is currently undergoing expansion and will be adding another highly efficient optical sorter. The company is also expanding mining operations through a joint venture with former owners of the Rocha emerald mine, which borders Belmont to the north. Rocha opened in 2005 but closed after only a few years. The new joint venture is a 50/50 split between Belmont and the Rocha group, and Rocha has been renamed the Canaan mine, its original name. Discus sions are ongoing between the mining partnersand the land owner, who prefers the operation be an underground mine. Under Brazilian law a percentage of the production goes to the land owner, even when another company owns the mining rights. Belmont has opened a tunnel entrance into the Canaan mine that is currently 120 m long. Once it is 400 m long and 50 m deep, the drive-in tunnel will reach the mineralized zone, where core samples showed emerald-bearing rock. Belmont estimates that by July 2012 it will be removing the first trucks of emeraldbearing ore from Canaan for processing. Mr. Ribeiro expects a production rate comparable to that of the underground operation at Belmont, which is 3.5 to 4 g of emerald per tonne of ore. He believes the emeralds will be larger but have a lighter color due to lower chromium content.

Belmont’s water reclamation system incorporates a five-pond system that uses filtering and gravity to remove particles introduced by mining and processing. With plans to increase underground mining, there will be less fine particle overburden to remove by washing, resulting in less need for water. The company expects its water reclamation to be even more efficient and less expensive at that point, minimizing the impact on the environment.

Belmont estimates the life of the mine according to the market price for emerald. If the price goes up 30%, the mine’s life expectancy doubles. If the price drops 30%, the life of the mine is cut in half. At current prices, Mr. Ribeiro expects 20–30 more years of profitable operation unless the production rate increases significantly. Also contributing to the mine’s life span is the fact that Belmont cuts some of its own rough, thus moving up the value chain and recording higher profits per tonne of ore mined. By earning more revenue per tonne, Belmont can afford to mine deeper underground.

They currently cut 25% of the production by value (10% by volume). All of their cutting is done close to the mine.

	Capoeirana, Minas Gerais
Emeralds were discovered in the Capoeirana area of Nova Era in 1988. Here the extraction is done primarily by independent miners and smaller-scale operations. The emeralds can be of very good color and quality, surpassing those previously produced from Santa Terezinha de Goiás.

In 2004, this contributor saw considerable activity by independent miners in pits, tunnels, and shafts. The work was very labor intensive. The miners used some explosives but mostly hammers, picks, and shovels. They would load the ore in wheelbarrows, take it to a washing area, and dump a barrel of water over it. The miners would then use hammers to break up some of the larger pieces of schist, shovel the ore onto a washing screen, and continue breaking the pieces with a hammer. They would then sort through the screen by hand to look for any schist that contained emerald crystals (figure 3).

Figure 3. Much of the production at Capoeirana is done by independent miners. The processing of the ore is accomplished by simple hand washing. Photo by A. Lucas.
One operation was somewhat mechanized: The miner was strapped to a cable and lowered by a winch into the mine and then brought back up with bags full of ore to be processed.

A 2009 visit to the Capoeirana area revealed that things had changed considerably since 2004. This time there were far fewer miners working, and the village itself seemed noticeably quieter—there were no dealers in the street, and nobody offered emerald crystals for sale. One reason given for the downturn was that the area’s mines were becoming too deep for independent miners. Some of the shafts were reaching depths of 100 m, where it was difficult to work the hard rock using ladders and hand tools. Also, some of the underground workings were becoming very close to each other, and the thin walls between them increased the risk of cave-ins. The global economic recession also took its toll on the Capoeirana emerald miners, as it has on the entire Brazilian gem industry. Because emeralds are traded in the U.S. dollar and the Brazilian real has gained so dramatically against the dollar, it has become very difficult for these inde pendent miners to make a living. Many have moved on to other areas where the deposits might be easier to work, while others have returned to agriculture. Companies such as Belmont were looking to purchase some of these properties so they could bring in a more sophisticated and profitable operation.

Mining at Capoeirana is done by a cooperative in which individual miners hold rights to sections of the deposit. The miners must be part of the cooperative, and they can only buy mining rights from individuals who have purchased theirs from the cooperative.

The Montebello mine, under the management of Sergio Martins (Stone World, São Paulo), is a small but fairly mechanized operation, especially for Capoeirana, where most of the mining is done by garimpeiros. Montebello is an underground mine where the miners drill into the mica schist (figure 4) and load the holes with explosives. Using various hand tools and shovels, they load carts with ore. The carts are pulled along tracks to take the ore to the elevator, where it is hauled up to the surface for processing. The mineralized zone is approximately 100 m wide and 300 m deep.

Figure 4. At Montebello, miners drill into the hard schist to prepare it for blasting. Photo by A. Lucas.
Processing at the Montebello mine is also more sophisticated than elsewhere in the Capoeirana area. After washing the ore through sluices, the workers put it on a sorting table and carefully look for emerald crystals in the schist.

In recent months, since the beginning of the more sophisticated small-scale operations such as Monte - bello, Capoeirana has turned out fine-quality material and faceted stones from 10 to 20 ct. Overall production figures are hard to estimate due to the degree of smallscale mining, but a low estimate for the last two years is 20 to 30 kg per month of facet-grade material, with fine-quality material accounting for at least 1 to 2 kg of the total. Emeralds from this area tend to be larger, and it is rare to find rough less than 1 g (e.g., figure 5). However, most of the crystals break during removal from the schist. Even the broken pieces can weigh 20–50 g, and rough fragments as large as 1 kg have been recovered. The higher-quality material is typically kept in Brazil for cutting, with the rest exported primarily to India.

	Figure 5. Emerald crystals recovered from the schist at Capoeirana can be large. Photo
	by A. Lucas.

	Bahia
The state of Bahia produces approximately 500 to 1,000 kg of emerald each month, but the quality is usually lower than that of Itabira/Nova Era. While there aresome fine-quality stones from Bahia, the vast majority are highly included. Most of the mining is done by garimpeiros, in the Carnaíba and Socotó areas.

	Santa Terezinha de Goiás
Santa Terezinha in Goiás State was an important emerald-producing area from the 1970s through the 1990s, but the last decade has seen little production. One of the advantages of this area was that the emeralds were found by mining the deposit in a straight line. Because the emeralds were fairly evenly distributed, production was consistent and predictable. This is completely different from emerald mining in Itabira/Nova Era, where the gems are locally concentrated and output is more sporadic.

At Santa Terezinha, emeralds were found in talccarbonate schist as opposed to Nova Era’s harder mica schist. This made extraction of the emerald crystals easier.

	Cutting and Trading
Brazil’s emerald production goes to both domestic cutters and foreign buyers who take the rough back to cutting centers in their own countries. Companies from Jaipur, India, are able to buy entire mine productions because their cutting facilities can handle all sizes and qualities of emerald, and they have a market for the entire range of goods. This gives them a considerable advantage, allowing them to offer a good price for the entire production. Brazilian cutters have higher labor costs, so they must gear their operations toward the product they can sell for a price that absorbs these costs. Rather than purchasing the entire mine production, they must buy a pick of the mine production—and pay a higher price for it. They have become adept at paying just enough to make it enticing for the miners to sell them the better quality and sizes, while staying competitive in the global market. Brazilian cutters have found a niche in fine-quality calibrated goods that are enticing to manu facturers worldwide (figure 6). This enables them to hit a profitable price point, and they can also cut larger, good-quality emeralds.

Figure 6. The wholesale emerald trade in Brazil is quite active. Businesses such as Sergio Martins’ Stone World (shown here in his former office at Teofilo Otoni) enjoy a thriving international and domestic market. Photo by A. Lucas.

	The Future
There are substantial challenges facing the Brazilian emerald industry. Stricter environmental regulations increase the cost of mining and make future finds less likely. The cost of labor is constantly rising, making it necessary to invest in technology. As the Brazilian real grows stronger against the dollar, the revenue that can be realized is declining while costs are increasing. Yet the potential for emerald production from the Itabira/Nova Era belt remains extremely promising. These deposits may very well warrant the investment needed for exploitation.

With advanced mining technology, plus high-end domestic cutting generating greater revenue and moving mining companies up the value chain, the future of the Brazilian emerald industry looks very encouraging. @chapter:18


Publication Year: 1996 Title: An Update on Imperial Topaz from the Capao Mine, Minas Gerais, Brazil Abstract: The Capão mine is one of the oldest and most productive fully mechanized Imperial topaz mines in the historic Ouro Preto area of Minas Gerais, Brazil. Bulldozers, water cannons, and dragscrapers are used in two main pits to remove the thick brown overburden for processing to recover topaz crystals in a broad range of sizes and colors. The rarest color is pinkish purple to purple. Heat treatment will turn some brownish yellow or orange Imperial topaz to "peach" or pink. Preliminary testing suggests that there may be a difference in fluorescence between heat-treated and non-heat-treated topaz. @chapter:3


Publication Year: 2020 Title: Unusually Large Grandidierite Abstract: A green-blue translucent to semi-translucent grandidierite weighing 763.5 ct. Photo by Diego Sanchez.

The Carlsbad laboratory received a green-blue translucent to semi-translucent stone weighing approximately 763.5 ct and measuring 50.32 × 48.15 × 36.17 mm (see above). Standard gemological examination revealed a refractive index of 1.621–1.581, weak green-blue to green pleochroism, and absorption lines at 480 and 490 nm seen in the handheld spectroscope. Examination with a standard gemological microscope revealed the stone to be heavily included with fractures, fine particulate clouds, and miscellaneous whitish minerals. The results from Raman spectroscopy, microscopic observations, and standard gemological examination were consistent with the rare mineral grandidierite.
Named after French naturalist Alfred Grandidier (1836–1912), grandidierite is a very rare mineral first discovered in 1902 at the cliffs of Andrahomana on the southern coast of Madagascar (D. Bruyere et al., “A new deposit of gem-quality grandidierite in Madagascar,” Fall 2016 G&G, pp. 266–275). Gem-quality material of facetable size was not found in the market until after the summer of 2015 (Winter 2015 Gem News International, pp. 449–450). Grandidierite is found in various localities as an accessory mineral in aluminous boron-rich pegmatites and in rocks subjected to local high-temperature, low-pressure metamorphism such as contact aureoles and xenoliths (again, see D. Bruyere et al., 2016). It very seldom reaches large sizes, and this is the largest grandidierite GIA has seen to date. @chapter:5