# Publication Year: -
# Title: Gem Buyers Beware: Get Rich Quick Scams
# Abstract: One of the best ways you can ensure you are not getting scammed is to research gems in person with an expert. Visit retailers and ask if they have a GIA Graduate Gemologist on staff. They can show you examples of gems you are interested in and tell you about them so you can make an informed purchase.

	People’s love of diamonds and other gemstones runs deep. Even the most ancient cultures prized them for adornment and as tangible symbols of wealth.

	In modern times, the unscrupulous play on people's deep love for gemstones and the notion of a gem’s lasting value. They employ dubious get rich quick schemes – so-called diamond and gem investments – to take advantage of the gullible and scam them.

	While quality gemstones generally maintain their value if purchased at a fair price and held over a long period of time, scammers tempt buyers by promising get-rich-quick profits or protection for their money in times of economic uncertainty. The “deal” often degenerates and the buyer is left holding greatly overpriced gems.

	There are several different ways these scammers go about taking consumers’ money. Here are four of the most common get rich quick scams.

	Gem Scam #1: The “Boiler Room”

	This very common scam begins with an unsolicited phone call or email, or perhaps a website link bearing a provocative headline lurking in the corner of a legitimate news or ecommerce site. The seller shows or describes sumptuous-looking gemstones and goes on to tell prospective buyers how they can get rich quick by obtaining stones worth as much as 10 times their purchase prices by “buying direct from the source.”

	Those who follow up are subjected to a high-pressure, often convincing sales pitch – always centered around the threat that this opportunity for big profits will be gone in a flash. Or this variation: “We have a European buyer who has given us a much better offer ... if you buy this gemstone, you could resell it through us for a tidy profit.”

	If the buyer hesitates, the real pressure starts: “Most people lose opportunities because they are afraid. Are YOU afraid of making $50,000 or even $100,000?” By now, the vast majority of prospects have tuned out − but some people can’t resist a “bargain” and send them a check.

	Often, the scammers gain their victims’ trust by first offering a stone for $100 or $200. They then call the customer back offering to repurchase it for a substantially higher price, but strongly suggest they apply that credit to a much costlier stone − $2,000 to $5,000 − that has even greater appreciation potential. If the customer takes the deal … well, you know what happens next.

	A typical example of this get rich quick scam: Some years ago the newspapers wrote about a physician who, after receiving several phone calls from such an operation, purchased two emeralds for $12,150. When the buyer had them appraised, their combined value totaled about $900. The company that sold him the emeralds raked in more than $35 million from other buyers before it closed down.

	Scammers usually try to delay consumer complaints by sending the gemstones in sealed containers with the warning that breaking the seal will invalidate any buy-back guarantee.

	Prosecutions are rare in most of these cases because these scammers shut down operations after complaints to law enforcement and consumer agencies begin to filter in. And quite often they go back in business under a new name in search of more victims.

	Gem Scam #2: The Ponzi Scheme

	A more elaborate version of the Boiler Room scam is a Ponzi scheme. Early investors are paid large returns on their purchases to get the attention of financial advisors who then, often unwittingly, place their clients’ money into gemstones from that seller.

	One recent get rich quick scam involved a company that claimed to control amber “mines” in the Dominican Republic and Argentina and offered buyers shares with the profits to be paid in Bitcoin, the cyber currency. Investors who put up $10,000 were promised returns as high as 6,400%.  The U.S. Securities and Exchange Commission (SEC), which shut the operation down in 2015, reported that after a few initial investors were paid, the remainder lost all of their funds. The SEC confirmed losses of $32 million, but estimated that the total could go as high as $100 million.

	Gem Scam #3: “Financial Security” Scams

	Another type of diamond and gem investment scam targets individuals who fear hyper-inflation or cataclysmic financial and social collapse. Scam operators obtain names from sellers of other “survivalist” or “hard-asset” products and relentlessly target prospective buyers with the message that cash and stocks will become near worthless in the coming crash − but they can preserve their wealth by holding gemstones and diamonds. While the pitches are different, the operation and outcomes are usually the same.

	While most of these companies close down fairly quickly before law enforcement agencies have a chance to react to complaints, they invariably sell buyers’ information to other scammers, who then offer to buy the stones at a fraction of their cost or a trade-in against the purchase of a much more valuable stone. This stone, of course, turns out to be as worthless as the first one.

	Gem Scam #4: The Tourist Trap

	While not exactly a get rich quick scheme, this gem scam takes advantage of those looking for that ‘great deal’ when making a gem or jewelry purchase. The scam is face-to-face, and often happens to people relaxing on vacation.

	Tourists love to purchase jewelry on their trips, especially in resort destinations and cruise ship ports. And while there are many trustworthy, established businesses selling gemstones in these places, there also are scammers selling imitation or highly treated stones worth a tiny fraction of their purchase price.

	The pitch often starts with a “tout” who approaches window shoppers outside established retailers. They have a “friend who’s a gem wholesaler” and, sure enough, that $1,000 ruby ring in the retailer’s window is only $400 from the back-alley dealer. By the time the buyer finds out it’s a synthetic or a glass-filled ruby of little value, he or she is back home with no recourse.

	Know How to Protect Yourself

	How do you protect yourself from scammers and distinguish them for honest sellers?

	Criminologists call such scams “crimes of persuasion,” which means the seller is skilled at penetrating natural defenses and logic with get-rich-quick promises of wealth or they play to the fears of their “mark.”

Be alert. Be wary of unsolicited telephone calls, emails or Internet sellers offering gems for investment. Keep your natural defense system working.

Remember the grander the promise, the greater likelihood of disappointment. If a 10-fold profit sounds too good to be true, then it surely is. There are no honest shortcuts to wealth and high profit in the gemstone and diamond business. The vast majority of gemstones and diamonds are traded through long-established networks where prices are well-established. Prices do vary greatly when you are talking about the quality of the gemstone – as with any natural product, there is a very broad range of quality available and prices vary accordingly.

	For example, a one carat diamond that is highly flawed and has a very noticeable tint, will trade for less than 10% of a flawless stone of the same size with top color. The story is much the same with ruby, emerald and sapphire. So, chances are the beautiful stone you see in the photographs will look a lot less appealing when the package arrives.

	Prices of gemstones do not fluctuate so wildly that they make it possible for a buyer to make a 5, 10 or 1,000 percent profit within a few months. If stones rose in price that quickly, the seller would be keeping them for his or herself and not be trying to sell them to you.

Learn about the factors that influence gemstone values. Take the time to understand the 4Cs of diamond quality (color, clarity, cut and carat weight) and their effect on price. Familiarize yourself with common gemstone treatments, synthetics and imitations. Learn how the quality and value of gemstones are determined, and you’ll be better prepared to recognize a legitimate offer. GIA’s Gem Encyclopedia is an excellent source of information about diamonds and gemstones and the factors that make them rare, appealing and valuable.

Insist on a world-recognized, independent, grading report like GIA’s for any gemstone purchase. A GIA Diamond Grading Report provides an objective assessment of a diamond’s quality based on the 4C’s and discloses any permanent treatments that may have been done to enhance its appearance. For added security, GIA will laser inscribe the report number on the diamond’s girdle.

	GIA reports are also available for all colored stones and pearls. These reports identify whether or not the gemstone is natural or synthetic and describe any treatments made to it.

	If you’re presented with a gemstone and a GIA report, you can use Report Check to verify that the report results match those listed in the GIA database.

Research gems by seeing them in person. Visit retailers and, if they have a GIA Graduate Gemologist on staff, ask her or him to show you examples and tell you about the gem so you can make an informed purchase. If you have any doubts about a gemstone with a report that you already own, they will be able to help you determine whether or not it is the gem described in the report.

	A gemstone may not bring instant profits − but it will enhance your life by its beauty. @chapter:49 @chapter:3 @chapter:49


# Publication Year: -
# Title: Paramagnetic Hole Centres in Natural Zircon and Zircon Colouration
# Abstract: This article explores atomic defect centers (color centers) of natural zircon from three localities (North Carolina, the Massif Central in the south of France, and the Ural Mountains of Russia). The origin of zircon coloration is little discussed in the spectroscopic literature. This study further explores paramagnetic properties and optical absorption, and also suggests additional constraints in the nature of some of the color centers occurring in natural zircon.

Electron paramagnetic resonance (EPR, an absorption technique using magnetic fields to measure transition energies in atomic defect centers) and optical absorption spectroscopy are used on a heterogeneous sample group of eleven small untreated zircon crystals. The findings indicate an obvious correlation between colors and certain paramagnetic defect centers in the crystal structure. However, the EPR studies also show that the presence of tetragonal centers of trivalent rare-earth elements and niobium is not directly related to any specific zircon coloration.

The paper discusses the highly technical EPR spectral indications for electron and hole defect centers (e.g., angular dependencies and crystal axes; principal g-values, etc.), as well as the intricate substitutional charge patterns which reflect the isomorphism of zircon.

The optical absorption spectra in samples from the US and France (from colorless through pinkish to reddish and brownish) show one type of spectra, two broad bands, 340–350 nm and 510–515 nm. The Russian samples (from colorless through yellowish-brownish) are different, showing a more complicated spectra of three dominant bands at 320, 390, and 420 nm and a weak band at 510.

The results confirm that the subdivision of these two common color series is meaningful.

Abstracted by Edward R. Blomgren @chapter:18 @chapter:0 @chapter:18


# Publication Year: 2020
# Title: A New Deposit of Pink Natrolite from Indonesia
# Abstract: Figure 1. Rough stones and polished cabochons of pink natrolite. The heart-shaped cabochon is 35.6 mm wide. Photo by Yu-Ho Li.

In early 2020, a parcel of stones representing some unique material found in early 2020 from the island of Nusa Kambangan, Central Java, Indonesia, was sent to Taiwan Union Lab of Gem Research (TULAB) for certification service. At the beginning, wholesalers claimed that the gemstone was thomsonite. Because its texture was very similar to the green-blue pectolite variety Larimar produced in the Dominican Republic, the stone was also misrepresented with the trade name “pink Larimar.”
By observing the rough stones with host rocks provided by the supplier, the occurrence was found to be vein-filling or cavity-filling within basalt. These stones had orange-pink to brownish pink color with white zoning and showed a botryoidal or radial crystal habit (figure 1).

Figure 2. Stacked Raman spectra of the pink natrolite from Indonesia compared to those of natrolite and thomsonite published in the RRUFF database; all spectra are normalized and baseline corrected.

Figure 3. The normalized visible-light transmission spectrum of pink natrolite shows a wide absorption band at 400–570 nm that results in a brownish pink to orange-pink color.
The average specific gravity of this parcel of gemstones was 2.24, and the spot RI was 1.49. With the owner’s consent, the parcel of polycrystalline material was tested with a Vickers hardness tester. The values were converted to Mohs hardness and ranged from 4.4 to 4.6. The samples’ Raman spectra were analyzed and compared to the RRUFF mineral spectral database; unexpectedly, the results were consistent with published spectra of natrolite (Na2Al2Si3O10·2H2O) instead of thomsonite (NaCa2Al5Si5O20·6H2O) (figure 2). The UV-Vis spectra revealed that the pink natrolite stones had a wide absorption band at 400–570 nm (figure 3). The EDXRF results also indicated that the pink gemstone was natrolite and contained a trace iron component. On the basis of EDXRF and UV-Vis results, the orange-pink to brownish pink color appeared to have been caused by Fe3+; however, this presumption still needs further verification.
This natrolite from Indonesia has a unique rose pink color and Larimar-like texture on polished surfaces, which is not common in natrolite from other localities. Although initially misrepresented by the merchant as thomsonite or pink Larimar, its beautiful appearance and durability are indeed comparable to Larimar. Subsequently, a new trade name “rhodatrolite,” meaning “rose natrolite,” was developed by the merchant for marketing this gemstone because of its color and texture. With enough mine production, pink natrolite from Indonesia has the potential to become a popular gemstone on the market. @chapter:12 @chapter:0 @chapter:12


# Publication Year: -
# Title: Books: Van Cleef & Arpels: Treasures and Legends
# Abstract: By Vincent Meylan, hardcover, 344 pp., publ. by Antique Collectors Club, 2014, $95.00.

Van Cleef & Arpels: Treasures and Legends by Vincent Meylan delves into the glittering world of the venerable Parisian jewelry firm. Meylan explores the glamorous and exotic patrons who commissioned and collected these pieces, and the world in which they lived. Each chapter of Treasures and Legends is filled with both color and black-and-white photos of necklaces, rings, bracelets, brooches, and earrings. Some images show the firm’s pieces as worn by many of the prominent collectors over the past century. The original design sketches often accompany photos from the VC&A archives.

History buffs will enjoy the stories of royalty, particularly the maharajas and maharanis of Baroda (now Vadodara), India. The vast wealth of jewels that were collected in the Indian principalities is legendary, and Baroda, in Gujarat, was one of the wealthiest. The three-tier great ceremonial diamond collar necklace of Baroda, one of the crown jewels of the state, was made for Maharaja Khanderao in 1864. The necklace contained three of the world's most important diamonds: the Dresden Green, the Star of the South, and the Eugénie. At the time of its creation, it was the most valuable piece of jewelry in the world. The author traces the history of these and other magnificent jewels of Baroda, as well as the colorful and sometimes tragic stories of their owners, such as Maharani Seta Devi of Baroda. With India's independence in 1947, many maharajas had to sell their treasures to sustain their large homes. Seta Devi moved to Paris instead, where she was known for lavish parties and extravagant living. But eventually her money ran out, her beloved son was murdered, and she died in obscurity in 1989.

Other royal stories involve the coronation and crown jewels of the Shah of Iran, as well as the coronation crown of his third wife, Farah Diba. Intimate family photos and sumptuous coronation images highlight the story of the firm’s greatest commission. A first-hand account by Pierre Arpels adds to the interesting narrative of this journey to create these royal treasures. The Duke and Duchess of Windsor’s famous love affair was documented by many of the pieces of jewelry that he purchased for her at the great jewelry houses of Paris. The Duchess is seen wearing their pieces in many candid photos of them in social settings. Their wedding day photo shows the Duchess wearing her wedding gift: a large sapphire and diamond Mystery-set Jarretière bracelet from Van Cleef & Arpels.

Meylan also explores the role VC&A played in the world of Hollywood royalty. Marlene Dietrich was seen wearing her large ruby and diamond Jarretière bracelet in more than one film. At her death, Elizabeth Taylor’s estate contained more jewelry pieces from Van Cleef & Arpels than from any other jewelry house. Several of her impressive pieces are displayed in this book, and with them their stories of love and passion that defined Taylor’s life. Meylan names other luminaries, such as Barbara Hutton and Grace Kelly, as fans of the jewelry house.

The book ends with a chapter on the personalities in the family, including founders Esther Arpels and Alfred Van Cleef, their daughter Renée Puissant, and Esther’s brothers Charles, Julian, and Louis Arpels. Puissant in particular plays a fascinating role in the company’s history, becoming the artistic director of the firm in 1926. In the 1930s, under her direction, some of the firm’s most iconic pieces, including the “Mystery Setting” and the “Zipper Necklace,” are created. Van Cleef & Arpels: Treasures and Legends takes the reader on a historical journey filled with stunning pieces and interesting characters throughout the world—characters connected with a golden thread, their love of the beautiful art of Van Cleef & Arpels. @chapter:25 @chapter:2 @chapter:25


# Publication Year: -
# Title: Winter 2019 G&G: Geographic Origin Special Issue
# Abstract: The Winter 2019 edition of Gems & Gemology is devoted to the determination of geographic origin for specific colored gemstones. This issue hopes to promote a healthy discussion about this complex subject, and bring greater transparency on the testing methods and criteria utilized in GIA’s laboratories.
The Geographic Origin Dilemma
Shane McClure and co-authors introduce the many facets of geographic origin determination. The authors explain that in order to adequately issue geographic origin reports, a laboratory must meet three requirements: scientific instrumentation, experienced gemologists, and a comprehensive collection of reference samples of known provenance.
Geology of Corundum and Emerald Gem Deposits: A Review
Similar geologic environments can produce gems with similar gemological properties, making it difficult to connect the properties of individual gems to the geology of their deposits. Gaston Giuliani and Lee Groat review the classification systems of corundum and emerald deposits, and discuss how genetic models can give geologic and geographic clues on their origins.
Field Gemology: Building a Research Collection and Understanding the Development of Gem Deposits
Wim Vertriest, Aaron Palke, and Nathan Renfro discuss the importance of building a reliable reference collection of known provenance in order to support geographic origin determination. Since gem-producing areas are constantly changing, field gemologists play a critical role in documenting the global mining and trading environment and the development of gemstone enhancement procedures.
A Review of Analytical Methods Used in Geographic Origin Determination of Gemstones
Origin determination is possible because there is a close relationship between the geology of an area and the properties of gemstones found there. Groat and co-authors take an in-depth look at the analytical techniques commonly used to characterize gemstones.
Geographic Origin of Specific Gemstones
In some cases, the value of a gemstone depends strongly on its geographic origin. Careful analysis of inclusions, trace element chemistry, and spectroscopic data often lead to conclusive origin determination. However, there are instances where the overlap in data is too great and laboratories are unable to make the call. Each article in this series—blue sapphire, ruby, emerald, Paraíba tourmaline, and alexandrite—outlines GIA’s methods and criteria for establishing geographic origin of that particular gemstone.
What’s Next?
What does the future hold for the geographic origin service? Could non-industry instrumentation and techniques be adapted to gemstone applications in order to improve consistency? McClure and co-authors explore whether developing a service for additional gemstones carries enough value to justify the expense. @chapter:4 @chapter:0 @chapter:4


# Publication Year: 2020
# Title: Nordic Gems and Jewelry
# Abstract: Figure 1. A cordierite Viking “sunstone” set in silver with the “vegvísir” compass symbol. Note that Mr. Berger’s ring also features a cordierite cabochon set in silver. Photo by Jennifer Stone-Sundberg.
At the JOGS show, Arctic Jewelry (Axvalla, Sweden) featured a variety of Nordic gemmy materials set mainly in silver using ancient, traditional, and contemporary Scandinavian designs. The pieces spoke to the mineral diversity, history, and artistry of the region.
The Vikings made navigation stones from locally sourced transparent crystals of minerals such as cordierite, a biaxial magnesium iron aluminum silicate, to help cross the seas under cloudy weather. These Viking “sunstones” are backed up by science, as cordierite and other materials such as calcite and tourmaline can be used to identify the position of the sun through even thick clouds. These stones visibly split sunlight into two images that when rotated to make equally bright, show rings of polarized light around the sun’s position. Cordierite was found to be the most accurate navigation stone in simulated journeys from Bergen, Norway, to the Viking settlement of Hyarf in Greenland (D. Száz and G. Horváth, “Success of sky-polarimetric Viking navigation: revealing the chance Viking sailors could reach Greenland from Norway,” Royal Society Open Science, Vol. 5, 2018, No. 172187). An example of a silver pendant engraved with a vegvísir (a Nordic compass “wayfinder” symbol) and a cordierite center stone was shown to us by Atle Berger (figure 1).

Figure 2. Examples of contemporary Scandinavian designs in silver containing thulite. Photo by Jennifer Stone-Sundberg; courtesy of Atle Berger.
Thulite, a manganese-containing pink variety of zoisite with some white calcite mottling, is the national gemstone of Norway, the country in which it was discovered by Anders Gustaf Ekeberg in 1820. The name comes from “Thule,” the ancient name for the mythical island (believed to be modern-day Norway) that was considered the northernmost part of the world. At the Arctic Jewelry booth, contemporary Scandinavian designs in silver incorporating this stone were featured in jewelry ranging from rings to bracelets and necklaces (figure 2).

Figure 3. Rough “Swedish Blue” slag byproduct. Photo by Kevin Schumacher; courtesy of Atle Berger.
A bright and attractive blue material found at the booth is the slag byproduct of iron smelting in the Bergslagen region of central Sweden during the Middle Ages. This material was reported on previously in G&G  (Winter 2006 GNI, p. 279) and characterized in the GIA lab. At that time, EDXRF was the method used for chemical analysis, but today with LA-ICP-MS we were able to more exactly determine the composition of this material from some rough pieces given to us by Mr. Berger (figure 3). We identified it as a silica-rich glass with a composition of 56.35 wt.% SiO2, 24.70 wt.% CaO, 7.68 wt.% MgO, 5.05 wt.% Al2O3, 2.23 wt.% FeO, 2.21 wt.% K2O, 0.85 wt.% MnO, 0.27 wt.% Na2O, and 0.65 wt.% other elements (average of 10 ICP spot analyses). This gave a calculated chemical formula of (Na0.019, Mg0.418, Al0.217, K0.103, Mn0.026, Fe2+0.068, others0.012)0.864 Si2.058 Ca0.967O6, which is generally consistent with what was reported in 2006. The oxide components are fairly normal for iron foundry slag, but the silica-rich nature is what gives this material its fine glassy aspect compared to those slags that are more CaO-rich. The slightly greenish blue color comes from Fe2+ (FeO). @chapter:31 @chapter:2 @chapter:31


# Publication Year: 2014
# Title: Polymer-Impregnated Aventurine Quartz, a New Imitation of “Ice Jade”
# Abstract: Figure 1. This light green semi-transparent bangle was made from polymer-impregnated aventurine quartz, a new imitation of “ice jade.” Photo courtesy of Lai Tai-An Gem Lab.

The market for jadeite jade is sizable, especially in the Far East. The variety and quantity of jadeite imitations is vast, a source of concern for the trade and consumers alike. A client recently submitted a polymer-impregnated aventurine quartz bangle to the Lai Tai-An Gem Lab in Taipei under the mistaken impression that it was jadeite jade.

The 212.90 ct bangle measured approximately 68 × 13 mm and exhibited a light green color, with a pleasant semi-transparent appearance that resembled a type of jadeite often referred to as “ice jade” (figure 1). Standard gemological testing gave a spot RI of 1.54 and an SG of approximately 2.66, and we observed inclusions of fuchsite mica, properties all consistent with aventurine quartz. More advanced methods, namely FTIR and Raman spectroscopy, were also applied. The FTIR spectrum (figure 2) revealed the polymer treatment of the piece. The long-wave UV light reaction was a very strong blue (figure 3), which appeared to confirm the treatment. Natural aventurine normally has an inert to weak reaction to long-wave UV light; by contrast, polymers generally show a moderate to very strong blue reaction. The acid-damaged surface structure observed with a microscope also corresponded with the treatment procedures used on jadeite.

Figure 2. FTIR testing of the bangle revealed polymer impregnation at the 3000–3100 cm–1 absorption in the mid-infrared region.

Figure 3. Notably, the bangle had a very strong blue reaction to long-wave UV light. Photo courtesy of Lai Tai-An Gem Lab.
In our experience, polymer-impregnated aventurine quartz is rarely encountered in the jewelry market. Still, its resemblance to “ice jade” shows that buyers should be fully aware of the potential risk of misidentifying such material. @chapter:46 @chapter:0 @chapter:46


# Publication Year: 1987
# Title: Spring 1987 G&G Lab Notes
# Abstract: Glass Imitation Beryl
Diamond with Interesting Inclusions
Synthetic Diamond
Diaspore, a Rare Gem Material
Goethite
Lodestone Magnetite
Nephrite Imitation
Unusual Clam "Pearl"
Pearls and their Apparent Colors
Quartz Fossiliferous Chalcedony
Phenomenal Quartz
Natural Ruby Doublet
Ruby with Unusual Cavities
Heated Sapphire

To view the full section, download the PDF above. @chapter:18 @chapter:1 @chapter:18


# Publication Year: 2016
# Title: Curved Tubes in Blue Sapphire
# Abstract: Curved linear features with healed fissures. The image was taken using a combination of darkfield and fiber-optic illumination. Photomicrograph by Victoria Raynaud; field of view 3.50 mm.

	During a GIA field expedition to Vietnam in May 2016, a 0.45 ct faceted blue sapphire containing numerous hair-like curved tubes (see above) was discovered at the gem market in Yen The. While the seller said the stone was mined in the Luc Yen area, this could not be confirmed. Unlike rubies and spinels, blue sapphires are not common in northern Vietnam. Analysis at GIA’s laboratory in Bangkok revealed that the stone had a metamorphic origin and had been heat treated. The tubes contained highly reflective glassy masses.

	Curved linear inclusions are well known in different types of gemstones. The most famous are probably the horsetails in demantoid garnet. Inclusions with a similar appearance have been observed in emeralds from Sandawana (Zimbabwe), quartz, and rhodonite (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Vols. 1 and 2, Opinio Verlag, Basel, Switzerland, 1986 and 2005; V. Pardieu, “Winza ruby? No sorry, my name is rhodonite!” http://www.giathai.net/rhodonite).

	In the corundum family, the only documented variety containing curved linear features are rubies from Winza, Tanzania (D. Schwarz et al., “Rubies and sapphires from Winza, central Tanzania,” Winter 2008 G&G, pp. 322–347). To our knowledge, these features have never been documented in blue sapphires. @chapter:24 @chapter:0 @chapter:24


# Publication Year: 2018
# Title: Diamond Geology
# Abstract: Modern Advances in the Understanding of Diamond Formation
D. Graham Pearson
University of Alberta, Edmonton, Canada
For the past 50 years, the majority of diamond research has focused on diamonds derived from the lithospheric mantle root underpinning ancient continents. While lithospheric diamonds are currently thought to form the mainstay of the world’s economic production, the continental mantle lithosphere reservoir comprises only ~2.5% of the total volume of Earth. Earth’s upper mantle and transition zone, extending from beneath the lithosphere to a depth of 670 km, occupy a volume approximately 10 times larger.
Diamonds from these deeper parts of the earth—“superdeep diamonds”—are more abundant than previously thought. They appear to dominate the high-value large diamond population that comes to market. Recent measurements of the carbon and nitrogen isotope composition of superdeep diamonds from Brazil and southern Africa, using in situ ion probe techniques, show that they document the deep recycling of volatile elements (C, N, O) from the surface of the earth to great depths, at least as deep as the uppermost lower mantle. The recycled crust signatures in these superdeep diamonds suggest their formation in regions of subducting oceanic plates, either in the convecting upper mantle or the transition zone plus lower mantle. It is likely that the deep subduction processes involved in forming these diamonds also transport surficial hydrogen into the deep mantle. This notion is supported by the observation of a high-pressure olivine polymorph—ringwoodite—with close to saturation levels of water. Hence, superdeep diamonds document a newly recognized, voluminous “diamond factory” in the deep earth, likely producing diamonds right up to the present day. Such diamonds also provide uniquely powerful views of how crustal material is recycled into the deep earth to replenish the mantle’s inventory of volatile elements.
The increasing recognition of superdeep diamonds in terms of their contribution to the diamond economy opens new horizons in diamond exploration. Models are heavily influenced by the search for diamonds associated with highly depleted peridotite (dunites and harzburgites). Such harzburgitic diamonds were formed in the Archean eon (>2.5 Ga) within lithospheric mantle of similar age. It is currently unclear what the association is between these ancient lithospheric diamonds and large, high-value diamonds, but it is likely a weak one. In contrast, the strong association between superdeep diamonds and these larger stones opens up a new paradigm because the available age constraints for superdeep diamonds indicate that they are much younger than the ancient lithospheric diamonds. Their younger age means that superdeep diamonds may be formed in non-Archean mantle, or mantle that has been strongly overprinted by post-Archean events that would otherwise be deemed unfavorable for the preservation of ancient lithospheric diamonds.
An additional factor in the search for new diamond deposits is the increasing recognition that major diamond deposits can form in lithospheric mantle that is younger than—or experienced major thermal disruption since—the canonical 2.5 billion years usually thought to be most favorable for diamond production.
This talk will explore these new dimensions in terms of the potential for discovering new diamond sources in “unconventional” settings.
Diamond Precipitation from High-Density CHO Fluids
Thomas Stachel1, Robert W. Luth1, and Oded Navon2
1University of Alberta, Edmonton, Canada
2Hebrew University, Jerusalem
Through research on inclusions in diamonds over the past 50 years, a detailed picture has emerged of the mineralogical and chemical composition of diamond substrates in Earth’s mantle and of the pressure-temperature conditions during diamond formation. The exact diamond-forming processes, however, are still a subject of debate.
One approach to constrain diamond-forming processes is through model calculations that aim to obtain the speciation and the carbon content of carbon-hydrogen-oxygen (CHO) fluids at particular O/(O+H) ratios and pressure-temperature conditions (using GFluid of Zhang and Duan, 2010, or other thermodynamic models of fluids). The predictions of such model calculations can then be tested against carbon and nitrogen stable isotopes and nitrogen content fractionation models, based on in situ analyses across homogenously grown diamond growth layers. Based on this approach, Luth and Stachel (2014) proposed that diamond precipitation occurs predominantly from cooling or ascending CHO fluids, composed of water with minor amounts of CO2 and CH4 (which in response to decreasing temperature may react to form diamond: CO2+ CH4 → 2C + 2H2O).
The second approach focuses on constraining the diamond-forming medium by studying submicrometer fluid inclusions in fibrous-clouded and, more recently, gem diamonds. Such studies established the presence of four compositional end members of inclusions: hydrous-saline, hydrous-silicic, high-Mg carbonatitic, and low-Mg carbonatitic (e.g., Navon et al., 1988; Weiss et al., 2009). Although these fluid inclusions only depict the state of the diamond-forming medium after formation, they nevertheless provide unique insights into the major and trace-element composition of such fluids that otherwise could not be obtained.
The apparent dichotomy between the two approaches—models for pure CHO fluids and actual observation of impure fluids (so-called high-density fluids) in clouded and fibrous diamonds—relates to the observation that in high-pressure and high-temperature experiments close to the melting temperature of mantle rocks, hydrous fluids contain 10–50% dissolved solid components (e.g., Kessel et al., 2015). Although at this stage the impurity content in natural CHO fluids cannot be included in numerical models, the findings for clouded and fibrous diamonds are not in conflict with the isochemical diamond precipitation model. Specifically, the fact that observed high-density inclusions are often carbonate bearing is not in conflict with the relatively reducing redox conditions associated with the O/(O+H) ratios of modeled diamond-forming CHO fluids. The model for the minimum redox stability of carbonate-bearing melts of Stagno and Frost (2010) permits fluid carbonate contents of up to about 30% at such redox conditions.

Figure 1. This illustration depicts the isochemical precipitation of diamond in Earth’s lithospheric mantle. Top: Intrusion of magma (ΔT to peridotitic wall rock is about +200°C) leads to release of hot CHO fluids from the crystallizing melt. As it infiltrates the peridotitic wall rock, the cooling fluid isochemically precipitates diamond. Bottom: After crystallization of the melt is completed, the intrusion is surrounded by an aureole of diamond, with temperature, volume, fluid content, and redox state of the melt all influencing the amount of diamond precipitated.
Although additional data need to be obtained to build a thermodynamic model for CHO fluids with dissolved silicates and to better characterize the major and trace-element composition of high-density CHO fluids in equilibrium with typical diamond substrates (the rock types peridotite and eclogite), we already see sufficient evidence to suggest that the two approaches described above are converging to a unified model of isochemical diamond precipitation from cooling or ascending high-density CHO fluids.
REFERENCES
Kessel R., Fumagalli P., Pettke T. (2015) The behaviour of incompatible elements during hydrous melting of metasomatized peridotite at 4–6 GPa and 1000°C–1200°C. Lithos, Vol. 236-237, pp. 141–155, https://doi.org/10.1016/j.lithos.2015.08.016

Luth R.W., Stachel T. (2014) The buffering capacity of lithospheric mantle: implications for diamond formation. Contributions to Mineralogy and Petrology, Vol. 168, No. 5, pp. 1–12, https://doi.org/10.1007/s00410-014-1083-6

Navon O., Hutcheon I.D., Rossman G.R., Wasserburg G.J. (1988) Mantle-derived fluids in diamond micro-inclusions. Nature, Vol. 335, No. 6193, pp. 784–789, https://doi.org/10.1038/335784a0

Stagno V., Frost D.J. (2010) Carbon speciation in the asthenosphere: Experimental measurements of the redox conditions at which carbonate-bearing melts coexist with graphite or diamond in peridotite assemblages. Earth and Planetary Science Letters, Vol. 300, No. 1-2, pp. 72–84, https://doi.org/10.1016/j.epsl.2010.09.038

Weiss Y., Kessel R., Griffin W.L., Kiflawi I., Klein-BenDavid, O., Bell D.R., Harris J.W., Navon O. (2009) A new model for the evolution of diamond-forming fluids: Evidence from microinclusion-bearing diamonds from Kankan, Guinea. Lithos, Vol. 112 (Supplement 2), pp. 660–674, https://doi.org/10.1016/j.lithos.2009.05.038

Zhang C., Duan Z.H. (2010) GFluid: An Excel spreadsheet for investigating C-O-H fluid composition under high temperatures and pressures. Computers & Geosciences, Vol. 36, No. 4, pp. 569–572, https://doi.org/10.1016/j.cageo.2009.05.008
How to Obtain and Interpret Diamond Ages
Steven B. Shirey1 and D. Graham Pearson2
1Carnegie Institution for Science, Washington, DC
2University of Alberta, Edmonton, Canada
Diamond ages are obtained from radiogenic isotopic analysis (Rb-Sr, Sm-Nd, Re-Os, and Ar-Ar) of mineral inclusions (garnet, pyroxene, and sulfide). As diamonds are xenocrysts that cannot be dated directly, the ages obtained on mineral inclusions provide a unique set of interpretive challenges to assure accuracy and account for preexisting history. A primary source of geological/mineralogical uncertainty on diamond ages is any process affecting protogenetic mineral inclusions before encapsulation in the diamond, especially if it occurred long before diamond formation. In practical application, the isotopic systems discussed above also carry with them inherent systemic uncertainties. Isotopic equilibrium is the essential condition required for the generation of a statistically robust isochron. Thus, isochron ages from multiple diamonds will record a valid and accurate age when the diamond-forming fluid promotes a large degree of isotopic equilibrium across grain scales, even for preexisting (“protogenetic”) minerals. This clearly can and does occur. Furthermore, it can be analytically tested for, and has multiple analogues in the field of dating metamorphic rocks. In cases where an age might be suspect, an age will be valid if its regression uncertainties can encompass a known and plausible geological event (especially one for which an association exists between that event and the source of diamond-forming fluids) and petrogenetic links can be established between inclusions on the isochron.

Figure 1. Left: Re-Os isotopic compositions for 10 sulfides from three Zimmi diamonds all fall along 650 Ma age arrays. Each diamond had multiple sulfides that lay on arrays of identical age, giving unequivocal evidence for the age and showing that these diamonds formed in the same episode of diamond formation. Right: Plane polarized light image of a typical sulfide inclusion in a polished Zimmi diamond plate. Note that this diamond only contains one inclusion, whereas analyses of three to four inclusions per diamond are shown in the plot on the left. From Smit et al. (2016), used with permission.

Diamonds can be dated in six basic ways:

model ages
radiogenic daughter Os ages (common-Os-free)
single-diamond mineral isochrons
core to rim ages
multiple single-diamond isochron/array ages
composite isochron/array ages

Model ages (1) are produced by the intersection between the evolution line for the inclusion and a reference reservoir such as the mantle. The most accurate single-diamond age is determined on a diamond with multiple inclusions (3). In this case an internal isochron can be obtained that not only establishes equilibrium among the multiple grains but also unequivocally dates the time of diamond growth. With extreme luck in obtaining the right diamond, concentric diamond growth zones visible in UV fluorescence or cathodoluminescence can sometimes be shown to constrain inclusions to occur in the core of the diamond and in the exterior at the rim. These single grains can be extracted to give a minimum growth time (4) for the diamond. In optimal situations, multiple inclusions are present within single growth zones, in single diamonds, allowing internal isochrons to be constructed for individual growth zones in single diamonds. If enough diamonds with inclusions can be obtained for study, valid ages for diamond populations can be obtained on multiple single-diamond ages that agree (5) or on composited, mineralogically similar inclusions to give an average age (6).
REFERENCE
Smit K.V., Shirey S.B., Wang W. (2016) Type Ib diamond formation and preservation in the West African lithospheric mantle: Re–Os age constraints from sulphide inclusions in Zimmi diamonds. Precambrian Research, Vol. 286, pp. 152–166, http://dx.doi.org/10.1016/j.precamres.2016.09.022
The Lesedi La Rona and the Constellation—The Puzzle of the Large Rough Diamonds from Karowe
Ulrika F.S. D’Haenens-Johansson
GIA, New York
In November 2015, Lucara Diamond’s operation at the Karowe mine in Botswana gained notoriety due to the extraction of a series of large colorless diamonds, including the 1,109 ct Lesedi La Rona and the 812 ct Constellation. The Lesedi La Rona marks the largest gem diamond recovered since the Cullinan (3,106 ct) in 1905. The Constellation, considered to be the seventh-largest recorded diamond, attained the highest price ever paid for a rough, selling for $63.1 million ($77,649 per carat). Additionally, three other significant colorless diamonds were recovered during the same period, weighing 374, 296, and 183 ct. Due to the similarity in their external characteristics—which include cleavage faces—as well as their extraction locations and dates, it was suspected that these stones might have originated from a larger rough that had broken. Lucara demonstrated that the 374 ct diamond and the Lesedi La Rona fit together, yet a large cleavage plane is still unaccounted for. GIA was able to study several rough and/or faceted pieces of these five diamonds using a range of spectroscopic and imaging techniques to gain insight into the presence and distribution of point defects in these diamonds.
Diamonds are commonly classified according to their nitrogen content measured by Fourier-transform infrared (FTIR) spectroscopy: Type I diamonds contain nitrogen in either isolated (Ib) or aggregated (IaAB) forms, while type II diamonds do not contain detectable nitrogen concentrations (IIa) but may contain boron (IIb). Analysis of faceted stones cut from the Lesedi La Rona indicates that the rough is a mixed-type diamond, containing both type IIa and pure type IaB regions. These types of diamonds, though exceedingly unusual, have been observed at GIA and reported by Delaunay and Fritsch (2017). The Constellation and the 374, 296, and 183 ct diamonds were determined to be type IaB, containing 20 ± 4 ppm B-aggregates (N4V), in agreement with the concentration for the type IaB pieces of the Lesedi La Rona. Pure type IaB diamonds such as these are actually quite rare, accounting for only 1.2% of a random suite of 5,060 large (>10 ct) D-to-Z diamonds submitted to GIA, whereas 24.6% were type II. Photoluminescence spectra further confirmed analogous defect content for the five large Karowe diamonds, with emissions from H4 (N4V20, 496 nm), H3 (NVN0, 503 nm), 505 nm, NV– (637 nm), and GR1 (V0, 741 nm) defects showing similar relative intensities and peak widths. Even for diamonds of the same type, parallel defect content and characteristics across such a variety of defects is unlikely for unrelated stones.
The external morphologies of the diamonds showed primary octahedral, resorbed, and fractured faces, with the Constellation and the 296 ct diamond featuring fractures containing metallic inclusions and secondary iron oxide staining. Deep UV fluorescence (< 230 nm) imaging elucidated the internal growth structures of the samples. For the Constellation and the 374, 296, and 183 ct diamonds, at least two growth zones with differing blue fluorescence intensities were observed within single pieces.
Combined with the spectroscopic data, these results provide compelling evidence that the Lesedi La Rona, the Constellation, and the 374, 296, and 183 ct diamonds from Karowe had comparable growth histories and likely originated from the same rough, with a combined weight of at least 2,774 ct.
REFERENCE
Delaunay A., Fritsch E. (2017) A zoned type IaB/IIa diamond of probable “superdeep” origin. Journal of Gemmology, Vol. 35, No. 5, pp. 397–399. @chapter:44 @chapter:1 @chapter:44


# Publication Year: 2024
# Title: Quarterly Crystal: Diamond in Diamond
# Abstract: Figure 1. With a weight of 0.71 ct and measuring 5.88 mm in longest dimension, this glassy colorless diamond octahedron contains an eye-visible diamond inclusion. Photo by Diego Sanchez.
Mineral inclusions in diamonds are always very interesting to gemologists and other geoscientists, and the colorful minerals such as bright green chromium diopside and orange almandine-pyrope usually attract the most attention. This Quarterly Crystal is slightly different, in that the inclusion is both transparent and colorless, with relatively low relief compared to the diamond crystal host. The parent diamond, a transparent colorless, gem-quality glassy octahedron, weighed 0.71 ct and measured 5.88 × 3.99 × 3.01 mm (figure 1). Reportedly from South Africa, the diamond was purchased at the Tucson shows from David New.
When inclusion-host pairs are composed of the same mineral, it causes a low-relief situation bordering on invisibility. Such inclusions become visible when the orientation of the inclusion is different or when there is an interface or partial interface between the host and the inclusion. In the case of diamond in diamond, if the inclusion is visible, then the interface can consist of various fluids and gases, other minerals (most commonly graphite formed through graphitization), combinations of all of these, or nothing at all.

Figure 2. Polarized light shows an elongated modified diamond octahedron displaying various degrees of interfacing with the host diamond crystal. Photomicrograph by Nathan Renfro; field of view 2.18 mm.
Examining the outline of the diamond inclusion in figure 2, there are areas at the interface where the inclusion and host diamond appear to blend perfectly and the interface seems to completely disappear. These are areas of perfect contact where the diamond inclusion and the diamond host merge, without any form of interfacial separation. @chapter:39 @chapter:1 @chapter:39


# Publication Year: 2017
# Title: Plastic Amber Imitation in a Rosary
# Abstract: Figure 1. Left: The rosary shows yellow to yellowish brown color in daylight-equivalent lighting (left). Right: The rosary under long-wave UV. The amber shows a moderate to strong chalky greenish blue and yellow reaction, but the plastic appears brown. Photos by Nazar Ahmed Ambalathveettil.

Dubai Central Laboratory (DCL) receives almost all types of ambers, natural and treated (e.g. heated, dyed, reconstructed) as well as amber imitations for identification. Amber rosaries (prayer beads) are increasingly popular in Middle East countries, especially the United Arab Emirates and Arabian Gulf countries.

Recently DCL received a rosary for amber identification. The yellow and yellowish brown color, structure, and size of the 102 beads were identical (figure 1, left). At first glance, even with a well-trained eye, this rosary could easily be misidentified as exclusively natural amber. Testing revealed that the rosary was strung with 71 heat-treated amber beads and 31 Bakelite plastic beads.

Spot refractive indices (RIs) of the amber beads were 1.53; observation between crossed polarization of most beads revealed anomalous double refraction with strained colors. Stress spangles and brown thread-like substances are the most noticeable inclusions in these beads; these features are commonly seen in heat-treated amber. The spot RIs of the plastic beads were around 1.64. Aggregate and anomalous double refraction reaction was observed under the polariscope and gas bubbles and swirl marks were the main inclusions.

The most interesting aspect of the specimen was its reaction under long-wave UV. The amber showed moderate to strong chalky greenish blue and yellow fluorescence, but the plastic appeared brown (figure 1, right).This reaction was very useful for differentiating between the two materials.

To confirm the identity of each material, we analyzed their infrared spectra with attenuated total reflectance (ATR) mode (figure 2). Spectrum A displayed main peaks at 1716.4 and 1161.1 cm–1, consistent with amber. The main peaks of Spectrum B were at 1650.8, 1600.7, and 1218.8 cm–1. After comparison with spectrum A and the spectra of other plastics, spectrum B confirmed the spot RI’s identification of this sample as Bakelite plastic.

Figure 2. IR spectra of the two specimens, with ATR method applied. Spectrum A
represents natural amber, with typical peaks at 1716.4 and 1161.1 cm–1. Spectrum B’s
main peaks at 1650.8, 1600.7, and 1218.8 cm–1 indicate that it is Bakelite plastic.
This rosary is an excellent example of the importance of testing and disclosure, because even an experienced person could not differentiate between the amber and Bakelite beads with the unaided eye. @chapter:46 @chapter:4 @chapter:46


# Publication Year: -
# Title: Blue Nile: Higher Diamond Prices Result in Reduced Sales
# Abstract: Engagement ring sales, which comprise about 55% of online diamond retailer Blue Nile's business, declined 4.6% in the second quarter  of 2014. Photo by Robert Weldon/GIA

	Online diamond retailer Blue Nile CEO Harvey Kantor worried publically at the close of 2013 that consumers were beginning to resist higher diamond prices. And as prices for diamonds have risen this year ‒ especially half-carat to one-carat stones ‒ Blue Nile’s sales have indeed been slowing.

	The company reported that “the diamond price environment” in the second quarter of this year resulted in a 1.3% decline in sales compared to the same period of 2013. While it is not the first sales decline in the company’s 15-year history, this one occurred within a relatively healthy retail environment after years of double-digit growth.

	The largest decline, 4.6%, was in engagement ring sales, while non-engagement ring sales increased 2.6%. Engagement ring sales comprise about 55% of the company’s business.

	Not surprisingly, Blue Nile’s sales declines were concentrated in stones smaller than one carat, a segment that had risen in price as much as 10% this year. Sales of larger diamonds, although a small part of the company’s revenue, actually increased because prices for these goods are relatively stable.

	Beyond diamond price increases, Blue Nile is facing strong competition from traditional jewelers building their online presence. So much so, that the company is toying with the idea of going brick-and-mortar – or at least brick-and-boutique.

	Blue Nile has set up trial boutiques in The Wedding Suites areas of two Nordstrom’s department stores, one in the Seattle area and one in suburban New York. Prospective buyers can look at and handle the diamond jewelry, but purchases are still completed online via an onsite computer or the customers’ mobile phones.

	The idea, Kantor said, was to increase the “conversion rate” (clicks to sales), particularly among consumers who check Blue Nile before going shopping for a diamond ring at retail jewelers.

	Blue Nile still anticipates an increase in sales for the calendar year, estimating between $475 and $490 million, compared to $450 million in 2013. That total represented a 12.5% increase from the previous year.

	The company hinted that it will resist further diamond price increases, which will increase the pressure of diamond manufacturers’ bottom lines, even as rough prices continue to climb.

	De Beers hiked prices an average of 2-3% at its July sight on medium quality rough that polishes to less than one carat – exactly the same goods Blue Nile claims are meeting consumer resistance. @chapter:32 @chapter:3 @chapter:32


# Publication Year: -
# Title: Examining a Rough Sapphire
# Abstract: GIA’s field gemologist shows how to examine a sapphire crystal for cracks and inclusions, which can be healed through heating with a chemical flux before the stone is cut.

	Examining a Rough Sapphire @chapter:19 @chapter:1 @chapter:19


# Publication Year: 2015
# Title: Coated Kornerupine Beads
# Abstract: Figure 1. These three kornerupine beads (0.95–1.38 ct) were found to have a metallic coating. Photo by Robison McMurtry.

Three dark brown faceted beads with an unusual metallic luster were recently submitted to the Carlsbad laboratory for identification service (figure 1). The three beads ranged from 0.95 ct to 1.38 ct. Standard gemological properties revealed an RI of approximately 1.668–1.680, consistent with kornerupine. The hydrostatic SG ranged from 3.01 to 3.19. This is slightly lower than expected for kornerupine, but can be explained by air trapped in the drill holes. Raman spectroscopy confirmed that the stones were kornerupine.

All three beads exhibited a high metallic luster with silver and bronze coloration, which is not typical for kornerupine. Under microscopic examination with reflected lighting, the surfaces showed spotty luster, consistent with a surface coating (figure 2). Further evidence of coating was visible along the facet junctions, where the coating was worn away.

Figure 2. Diffused reflected light exposed spotty luster on the surface of one of the tested
stones, indicating the presence of a coating. Photomicrograph by Amy Neurauter; field of
view 2.17 mm.
Energy-dispersive X-ray fluorescence (EDXRF) chemical analysis detected large amounts of Mg, Al, and Si, consistent with kornerupine. EDXRF also revealed the presence of copper. The authors could not find documentation of naturally occurring copper in kornerupine, so this element may have been used to create the metallic coating. This is the first time the GIA laboratory has seen coated kornerupine. @chapter:2 @chapter:0 @chapter:2


# Publication Year: 2005
# Title: Summer 2005 G&G Book Reviews
# Abstract: “101 Bench Tips for Jewelers”
By Alan Revere, 120 pp., illus., publ. by MJSA/AJM Press, Providence, RI, 2004. US$42.95 ($36.50 for MJSA members)

“Identification of Gemstones”
By Michael O’Donoghue and Louise Joyner, 313 pp., illus., publ. by Butterworth-Heinemann, Oxford, UK, 2003. US$59.95

“Minerals and Their Localities”
By Jan H. Bernard and Jaroslav Hyrsl, edited by Vandall T. King, 807 pp., illus., publ. by Granit, Praha, Czech Republic, 2004. US$145.00

“Masterpieces of the Mineral World: Treasures from The Houston Museum of Natural Science”
By Wendell E. Wilson and Joel A. Bartsch with Mark Mauthner, 264 pp., illus., publ. by The Houston Museum of Natural Science and The Mineralogical Record in association with Harry N. Abrams Inc., New York, 2004. US$75.00

To view the full section, download the PDF above. @chapter:17 @chapter:0 @chapter:17


# Publication Year: -
# Title: Bank Suspends Credit for ‘Unprofitable’ Rough Diamonds
# Abstract: Rio Tinto will hold its Argyle fancy colored diamond tender in September, a collection of 64 diamonds, including the 2019 Argyle pink diamond hero stones. They are, from left: the Argyle Verity, an oval shape, 1.37 ct Fancy Vivid purplish pink; the Argyle Enigma, a modified radiant, 1.75 ct Fancy red; the Argyle Amari, a heart-shaped, 1.48 ct Fancy Vivid purplish pink; the Argyle Opus, a round shape, 2.01 ct Fancy Intense pink; the Argyle Elysian, a modified cushion shape, 1.20 ct Fancy Vivid pink; and the Argyle Avenoir, an oval shape, 1.07 ct Fancy red. All were graded by GIA. Photo courtesy of Rio Tinto

De Beers and Alrosa both slashed their rough diamond sales in the second quarter of this year and further cuts are sure to come following ABN AMRO’s announcement that it will no longer finance rough purchases for goods that can’t be cut profitably – that includes the majority of sizes and qualities.
ABN AMRO’s restrictions are stringent. It defines “profitable” sales as those that can achieve “real sales margins for goods sold as soon as possible after purchase of rough without considering credit terms.” This means the bank is likely to finance only a narrow range of goods that are in demand; mostly medium to better quality diamonds above 0.5 cts.
The bank also said that clients wanting to use its rough buying credit facility need to apply on a case-by-case basis for the time being.
Diamond manufacturers in India report that prices have fallen as much as 10% on such diamonds in recent weeks, even though manufacturing output has declined about 40% from the same time last year.
Inventories of rough and polished diamonds in the major cutting centers – especially India – are approaching levels where the supply overhang causes polished prices to drop to levels where it is no longer profitable to cut rough – especially in goods that would result in 0.25 to 0.50 cts.
De Beers will certainly allocate another small cycle sale of rough diamond in July, following a very small June allotment. The May and June rough sales - the company’s smallest in several years - and disappointing results from the Las Vegas and Hong Kong trade shows have not helped diamond market sentiment. The company’s sales in the first half of the year are down nearly 20% compared to last year and will likely drop further during the second half of the year.
Alrosa announced that its rough diamond sales are down 33% by value for the first six months of this year, with June’s allocation down 43% compared to the same month last year. Sales will likely sink further after the ABN AMRO announcement.
Some manufacturers are expecting relief following Rio Tinto’s announcement that it will close its large Argyle diamond mine in Australia at the end of 2020. Rio had indicated it might close the mine on several occasions some years ago but, because inventories of rough and polished have been accumulating to the point that prices for both have been softening, the announcement is real this time.
It is unlikely, however, that taking Argyle’s 14 million carats out of the market will be a cure-all for the industry’s high inventories because much of the mine’s output filled a specific niche – millions of carats for low-priced mass market jewelry. The majority of Argyle’s production is small goods with a brownish tint and an average value of about $13 per carat. Removing such material from the market will not alleviate the large inventories of diamonds larger than 0.20 cts.
Just after making the mine closing announcement, Argyle unveiled its latest collection of fancy colored diamonds, which will go on sale at its annual tender sale in September. This year’s collection of 64 diamonds weighs a total of 56.28 cts.
The six hero stones, all graded by GIA, are the:

Argyle Verity, an oval shape, 1.37 ct Fancy Vivid purplish pink
Argyle Enigma, a modified radiant, 1.75 ct Fancy red
Argyle Amari, a heart-shaped, 1.48 ct Fancy Vivid purplish pink
Argyle Opus, a round shape, 2.01 ct Fancy Intense pink
Argyle Elysian, a modified cushion shape, 1.20 ct Fancy Vivid pink
Argyle Avenoir, an oval shape, 1.07 ct Fancy red

This will probably be the penultimate Argyle fancy colored diamond tender sale, which began in 1984. @chapter:37 @chapter:3 @chapter:37


# Publication Year: -
# Title: Winter 2008 G&G Book Reviews
# Abstract: “Photoatlas of Inclusions in Gemstones, Volume 3”
By E. J. Gübelin and J. I. Koivula, 672 pp., illus., publ. by Opinio Publishers, Basel, Switzerland [www.publications.microworldofgems.com], 2008. US$299.00

“Bulgari”
By Amanda Triossi and Daniela Mascetti, 2nd ed. (revised and updated by Amanda Triossi), 320 pp., illus., publ. by Abbeville Press, New York [www.abbeville.com], 2007. US$75.00

“Guidebook to the Pegmatites of Western Australia”
By Mark Ivan Jacobson, Mark Andrew Calderwood, and Benjamin Alexander Grguric, 356 pp., illus., publ. by Hesperian Press [www.hesperianpress.com], Victoria Park, Australia, 2007. US$85.00

“Crazy About Jewelry! The Expert Guide to Buying, Selling and Caring for Your Jewelry”
By Susan Eisen, 245 pp., illus., publ. by Full Circle International Publishing
[www.crazyaboutjewelry.net], El Paso, TX, 2007. US$16.95

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


# Publication Year: 2007
# Title: Yellow Mn-rich Tourmaline from the Canary Mining Area, Zambia
# Abstract: The most important source of yellow gem elbaite is the Canary mining area in the Lundazi District of eastern Zambia. The tourmaline has been mined since 1983 from both pegmatite and eluvial/alluvial deposits, in colors typically ranging from yellow-green to yellow to orange and brown; much of the orange-to-brown material is heated to attain a “golden” or “canary” yellow color. The tourmaline is Mn-rich (up to 9.18 wt.% MnO documented in the literature) and contains traces of Ti and little or no Fe. The distinctive composition of this tourmaline is probably the result of the crystallization of abundant schorl from an unusual B-rich, Li-poor pegmatite magma, which depleted Fe while conserving Mn until the late-stage crystallization of gem pockets.

	DATA DEPOSITORY

Table: Electron-Microprobe Analyses of Tourmaline from the Canary Mining Area, Zambia
	Submitted by Brendan Laurs
	Winter, 2007 @chapter:12 @chapter:0 @chapter:12


# Publication Year: 2013
# Title: Large Pinkish Brown CVD Synthetic Diamond
# Abstract: Figure 1. This 1.03 ct CVD synthetic is notable for its size and Faint pinkish brown color. Photo by Robison McMurtry.

              Distinguishing diamonds of natural and synthetic origin is one of the most important tasks of any gemological laboratory. With the advances in technology and methodology available to manufacturers, a wider variety of synthetic diamonds has begun to emerge. Recently, a client submitted a 1.03 ct emerald-cut synthetic diamond (figure 1) to the Carlsbad laboratory. We determined it had been grown from the chemical vapor deposition (CVD) process. This was evident from the large silicon-vacancy peak at 737 nm seen in both the UV-visible and photoluminescence spectra of this type IIa synthetic diamond. A lack of tatami strain and the distinctive growth patterns observed in the DiamondView (see W. Wang et al., “Latest-generation CVD-grown synthetic diamonds from Apollo Diamond Inc.” Winter 2007 G&G, pp. 294–312) confirmed the origin (figures 2 and 3).

	Figure 2. Viewed under crossed polarizers, this synthetic diamond shows mottled strain, but no tatami strain, consistent with its CVD growth origin. Photo by Troy Ardon.

	Figure 3. DiamondView imaging remains one of the most reliable methods for confirming a CVD synthetic diamond. This image shows distinctive growth patterns. Image by Sally Eaton-Magaña.
As the vast majority of CVD synthetic diamonds submitted to the lab weigh less than one carat, this sample was unusual for its size, as well as its color grade of Faint pinkish brown. This is the first colored CVD synthetic diamond examined by GIA that did not merit a “Fancy” modifier, but instead fell in the Faint to Light range. While pink CVD-grown synthetics have been documented, in most cases the color was generated by post-growth treatment. Here the pinkish color seemed solely related to the growth process, with no subsequent treatments (HPHT annealing, irradiation, and then annealing) coming into play. @chapter:9 @chapter:1 @chapter:9


# Publication Year: 2021
# Title: Gem Shopping Network: An Online Jewelry Business During the Pandemic
# Abstract: Figure 1. GSN show host Marvin Pierschbacher presents finished jewelry. Live shows are entertaining and educational, and therefore very well accepted by the audience. Courtesy of GSN.

The COVID-19 pandemic has forced many sectors to adopt new work routines and move their commerce online. This is also true for the gem and jewelry industry. However, some businesses have been on-air and online for quite a long time. One of the veterans is the Gem Shopping Network (GSN), headquartered near Atlanta.
Since 1997, GSN has grown from a weekend show to a network that reaches over 60 million U.S. households. From television to the web and more recently the mobile app, the network can livestream its gem and jewelry shows through all available channels. At the beginning of the pandemic early in 2020, GSN immediately adopted proper social distancing and regulations to keep its employees safe, which allowed the crew to operate without a pause. Show hosts continued livestreaming from the studios, entertaining and educating their audience (figure 1).
Because GSN carries a vast array of goods—from mineral specimens, faceted gemstones, and finished jewelry all the way to collectibles and estate jewelry—supply has been a critical component since its earliest days (figure 2).

Figure 2. Finished jewelry featuring a broad range of colored gemstones, including some exotic varieties, is one pillar product carried by GSN. Courtesy of GSN.
While some in-person sourcing was prohibited by the situation, the supply side of the business was not negatively impacted overall. Some suppliers who would normally provide goods through outlets such as the cruise ship industry were able to transfer them to online jewelry traders such as GSN.
The majority of GSN’s customers are women ages 50 to 65, a demographic that has been quite stable over the past two decades. This customer base proved advantageous when “staying at home” became the new normal as more time was available to watch the shows and purchase goods. Although international transportation was impacted by COVID-19, U.S. domestic shipping and delivery remained quite efficient. Steady supply, a stable customer base, and on-time delivery combined to make 2020 one of GSN’s strongest years financially.
As both a seller and an educator, GSN has its own gemology content production team. The pandemic unexpectedly allowed more time for the team to produce content, which is shared over the multiple streaming channels. High-quality content is one of the key pillars for any online seller as it is the tool to attract and maintain customers. As the world gradually recovers from the pandemic, online jewelry trading is expected to see strong growth in the future. @chapter:32 @chapter:3 @chapter:32


# Publication Year: 2023
# Title: The history of gemstones in Chanthaburi_33
# Abstract: Around the years 2540 to 2550, African gem traders began coming to Chanthaburi. Since then, approximately 20 years have passed. These African traders specialize in trading gems, particularly from Myanmar, here in Chanthaburi. They operate within a network where they sell gems directly at the Bang Rak Market initially, then gradually moving operations to Chanthaburi. Over time, they have integrated into the local community. African traders typically source gems from their own countries and have the capability to distribute them globally. However, Chanthaburi remains a hub where artisans can produce world-class gemstones. These gems are not easily replaced elsewhere due to the specialized skills and resources available in Chanthaburi. @chapter:31 @chapter:2 @chapter:31


# Publication Year: 1984
# Title: 'Cobalt-Blue' Gem Spinels
# Abstract: The traditional gemological technique for distinguishing natural from synthetic blue spinel has involved the use of refractive index and absorption spectra. Recently, however, the standard interpretation of these tests has proved troublesome in the identification of several intensely colored blue stones that have R.I.'s in the range of natural blue spinels but that exhibit spectral features generally associated with synthetic cobalt-colored spinels. To establish the origin of these specimens, a detailed investigation of natural, flame-fusion, and flux blue spinels was carried out. Our results indicate that, while spectral features in the longer wavelengths are unreliable for separating these spinels, an iron-related absorption band at about 460 nm was seen only in our natural specimens. Flame-fusion synthetics may still be distinguished by their lower R.I.'s. @chapter:24 @chapter:0 @chapter:24


# Publication Year: 2014
# Title: Dyed Marble as a Purple Sugilite Imitation
# Abstract: ABSTRACT
In the past two years, many sugilite products with a dark purple color and an obvious granular texture have appeared in the Chinese market. Sugilite pendants and bangles are very popular. Their internal texture and color distribution are inconsistent with previously documented natural specimens and suggest dyed artifacts. With that in mind, we obtained a “sugilite” bangle to investigate its gemological characteristics.

Figure 1. Testing of this bangle identified it as a dyed marble imitation of purple sugilite. Photo by Shanshan Du.
The bangle weighed about 71 grams and had a dark purple color that was distributed along the mineral grain boundaries (figure 1). Spot RIs of 1.48, 1.53, 1.57, and 1.63 were obtained from different areas of the bangle. Its hydrostatic SG was about 2.65, significantly lower than that of natural sugilite. The sample fluoresced strong purple and medium red under long- and short-wave UV radiation, respectively, which indicated treatment with organic dye(s). Five main peaks were observed in the 1600–700 cm–1 region of the FTIR spectrum (figure 2). The three peaks at 1427, 881, and 710 cm–1 are typical for calcite. The remaining two peaks at 1530 and 1505 cm–1 were believed to result from an organic dye.

Figure 2. The FTIR spectrum of the purple bangle contained characteristic peaks at 1427, 881, and 710 cm–1 that are typical for calcite.
Although the imitation resembles sugilite, its internal texture, RI, SG, fluorescence, and FTIR spectrum identify it as marble. Since marble usually occurs as a mineral aggregate with a loose texture, it is easily dyed to imitate other precious gemstones. We can therefore expect to see a steady influx of marble imitations in the market, and rigorous testing will be needed to protect consumers. @chapter:12 @chapter:0 @chapter:12


# Publication Year: -
# Title: GIA’s First Research Intern: Genesis of a Gemologist
# Abstract: Rachelle Turnier used Raman spectroscopy and photoluminescence mapping to better understand the formation of basalt-related sapphires, the focus of her Ph.D. work. Photo by Kevin Schumacher/GIA.

Rachelle Turnier, GIA’s first research intern, began her undergraduate studies in geology, but a fellowship at the American Museum of Natural History turned her interests to gemology. Her work there with curator George Harlow on determining the geological origins of syenite-hosted sapphires made her realize that a geology degree could apply to the world of gems.

“Gemstones are beautiful minerals,” Turnier says. “Not too many geologists are gem-focused. There was obviously a hole that needed to be filled.”

GIA’s Research Internship Program is the first for undergraduate and graduate students. The Institute also offers the Richard T. Liddicoat Postdoctoral Research Associate Fellowship, founded in 2014, for postdoctoral researchers.

Turnier, who was a first-year Ph.D. student in geochemistry and petrology at the University of Wisconsin–Madison when she interned at GIA in late 2017, researched the geological conditions of basalt-related sapphire formation. Many sapphires are found in alluvial deposits after they weather away from the host rock, leaving only the geochemistry of the sapphires and their inclusions to give clues about their formation.

During her two-and-a-half-month internship, Turnier used GIA’s extensive gem reference collection to document zircon inclusions in sapphire samples, analyzing them with Raman spectroscopy to determine at what depths the stones formed. She also used photoluminescence (PL) mapping to determine whether spectroscopic and growth features unique to sapphires from different deposits exist, finding vastly different PL intensities between Thai and Cambodian sapphires. This shows promise as a factor that could aid in country-of-origin determination, but further studies are needed.

“We have field gemologists choosing samples from the source at all these deposits,” says Aaron Palke, a senior research scientist at GIA who worked closely with Turnier. “One of the things we want to do is to bring in outside researchers to help us find the most value in the gem reference collection.”

Turnier returned to the University of Wisconsin and is researching oxygen isotopes in the zircon inclusions and the host sapphire. Using a secondary ion mass spectrometer, she is working to determine when and through what geologic processes the sapphires and inclusions formed.
“I just love instrumentation,” Turnier says. “And what better thing to do than study pretty rocks and minerals on cool instruments?”

The one- to two-month Research Internship Program is offered at GIA’s Carlsbad and New York locations. Candidates should be pursuing a bachelor’s or graduate degree in physics, materials science, geology, chemistry, or a related field and must be in their junior year or higher. Selected interns will work on a defined project and be mentored in spectroscopy and gemology by GIA research scientists and gemologists. A project conclusion will be reached by the end of the internship. An extension of the internship is possible.

Three interns are at work in the Carlsbad laboratory in 2018, studying color in ruby and sapphire, color in copper-bearing feldspar, and the spectroscopic signatures of yellow diamonds from Canada. The New York lab recently hosted an intern focusing on point defects in mineral-included superdeep type IIa diamonds from Juina, Brazil, and, early next year, a second will investigate color-forming defects in unusual yellow- and brown-grained type IaAB diamonds from Botswana.

Find out more about the GIA research internship program, qualifications, and application process. @chapter:16 @chapter:0 @chapter:16


# Publication Year: 1982
# Title: New Synthetic Rubies Made by Professor P. O. Knischka
# Abstract: A new synthetic ruby, developed by Professor P. O. Knischka using a method of gradient technique (not yet disclosed) through supercooling and saturation, has distinct crystallographic and gemological characteristics. Particularly notable are the great number of faces on the finished crystals and the identifying inclusions. @chapter:19 @chapter:1 @chapter:19


# Publication Year: 1983
# Title: Cobalt Glass as a Lapis Lazuli Imitation
# Abstract: A necklace of round beads offered as "blue quartz from India" was analyzed by gemological and additional advanced techniques. The violet-blue ornamental material, which resembled fine-quality lapis lazuli, turned out to be a nontransparent cobalt glass, unlike any glass observed before as a gem substitute. The characteristic color irregularities of lapis (white in blue) had been imitated by white crystallites of low-cristobalite included in the deep blue glass. @chapter:16 @chapter:0 @chapter:16


# Publication Year: -
# Title: Why are Pink Diamonds Pink?GIA Researchers Dive Deep into their Crystal Structure
# Abstract: These diamonds are from the 2016 Argyle Pink Tender in New York City. Left to right: 0.64 ct Fancy Deep pink oval, 0.75 ct Fancy Intense purplish pink trilliant, 0.91 ct Fancy Vivid purplish pink oval, 1.30 ct Fancy Intense pink heart, 1.35 ct Fancy Intense purplish pink cushion, 0.80 ct Fancy Vivid pink pear, and 0.45 ct Fancy Vivid purplish pink emerald cut. Courtesy of Argyle Pink Diamonds. Photo by Robert Weldon/GIA

Natural pink diamonds are among the most valuable and rare of Earth’s treasures. Top, vivid-colored stones can bring more than $2 million per carat at major auctions. Such prices come from their rarity as much as their beauty – only a tiny percentage of diamonds have pink color, and only a tiny percentage of these have a rich, vivid color.
Pink diamonds created in a laboratory, however, are quite different from most of their natural counterparts. Manufacturers can’t replicate the way the vast majority of these fancy colored diamonds formed in nature, according to GIA researchers.
Employing GIA’s immense database of more than 90,000 natural pink and related colored diamonds graded between 2008 and 2016, GIA researchers Dr. Sally Eaton-Magaña, senior research scientist; Troy Ardon, research associate; Dr. Karen V. Smit, research scientist; Dr. Christopher M. Breeding, senior research scientist and Dr. James Shigley, distinguished research fellow, produced the most detailed and comprehensive gemological analysis of pink diamonds to date, published in the Winter 2018 edition of the Institute’s quarterly journal, Gems & Gemology.

Natural-color pink diamonds are exceptional treasures. The lead article in this issue, based on GIA’s database of more than 90,000 diamonds in the pink, orangy pink, purple, red, and brown color continuum, summarizes their gemological and spectroscopic characteristics. Shown on the cover is the 18.96 ct Winston Pink Legacy, a Fancy Vivid pink emerald-cut diamond that recently sold at auction for more than $50 million. Winston Pink Legacy courtesy of Harry Winston, Inc. © 2018 Christie’s Images Limited
The sample set of 90,000-plus diamonds includes all those submitted to GIA from 2008 to 2016 with pink as a primary color, and also spans the color hue range from red to purple and saturation range from faint to dark, along with brown diamonds, which share a similar cause of color as pink and related stones. Many of those 90,000 diamonds were small, with low color saturation.
This research confirms that the color of 99.5% of pink diamonds comes from distortion in their crystal structure, not from trace elements, such as nitrogen, which causes yellow color in diamonds or boron, which causes blue. In pink diamonds containing nitrogen, the color is generally concentrated within parallel narrow bands called glide planes, lamellae, or pink/brown graining, depending upon the color. These lines are visible under a microscope and cutters orient them perpendicular to the table to maximize body color.
While many color-producing defects can be introduced through laboratory treatment processes, atomic level distortions in a diamond’s crystal structure created by plastic deformation cannot.
“We know that plastic deformation is associated with the vast majority of diamonds with these colors, but we still do not know the actual atomic structure of the defect causing the color,” says Breeding, who notes that the pink color is caused by a broad absorption band centered at 550 nanometer (nm) in spectroscopic analysis. Spectroscopic analysis is an important gemological tool to measure the impurities and other defects within a diamond (and other gemstones) that give rise to specific absorption peaks or bands in the visible spectrum. The researchers said that there is no known method of replicating plastic deformation with the 550 nm absorption band by a laboratory treatment or growth process.
All fancy colored diamonds submitted to GIA’s grading laboratories are subjected to rigorous analysis to be certain that the colors ‒ and the diamonds themselves ‒ are of natural origin, which makes the GIA database extensively detailed and valuable for research, Shigley said. He added that the team selected a representative sample of 1,000 pink diamonds to examine even more thoroughly for the Gems & Gemology article.

How are Laboratory-Grown Pink Diamonds Created?
There are laboratory-grown pink diamonds in the market, but they are created by three different methods, said Eaton-Magaña.
“The first, and by far the most common, is through irradiating (exposing to radiation) a laboratory-grown diamond that was grown with nitrogen impurities, then subjecting it to moderate temperatures (600°C to 1000°C) afterwards,” she said. “The vast majority of pink and related colors are made using this method.”
This process creates a defect in the crystal lattice (caused by a missing carbon atom adjacent to a nitrogen atom within the lattice) called a nitrogen-vacancy center that is responsible for the color. Eaton-Magaña said a tiny percentage of natural pink diamonds have this nitrogen-vacancy center, which is identifiable by spectroscopic lines at 575 nm and 637 nm.
“These nitrogen-vacancy pinks comprise about one half of one percent of the natural pinks in the GIA database,” she said. They are type IIa diamonds (a rare type of diamond with an exceptionally pure chemical composition: almost all carbon, with negligible amounts of nitrogen or boron) with a very uniform pink color and no visible colored lamellae. These stones are sometimes termed Golconda pinks, but they don’t necessarily have a connection to the Indian mine that closed in the late 18th century.
Generally, she noted, natural nitrogen-vacancy pinks have pale colors, while the laboratory-grown and treated diamonds are more highly colored. Additional testing, such as at a gemological laboratory, is essential to determine the cause of color in such diamonds.
The second method cited by the researchers occurs only in chemical vapor deposition laboratory-grown diamonds (CVD), where a 520 nm spectral band is created during growth that results in an orangy-pink color. GIA has only seen a few of these stones, they say, and the color was not as vibrant as other pink lab-grown diamonds.
The third method, which is even more rare, Eaton-Magaña said, is achieved by adding high amounts of silicon to the CVD growth process which, when exposed to UV illumination, creates reversible color change between the stable pink color and a temporary blue color.

Size and Color Statistics: Are Pink Diamonds Rare?
Of the group of diamonds in this study 47% were unmodified (no other color observed) pink; 28% were purplish pink to pinkish purple; 17% were brownish pink to pinkish brown; 10% were brownish orangy-pink to orangy-pink; 3% were brown; 1% were purple-brown, purple-gray and purple; and 0.9% were red, brown-red or orange red. Of the unmodified pink diamonds, 54% were graded faint to light pink.
While brown diamonds are among the most common fancy colors in nature, the low percentage of them in this group suggests that most are sold into the market without grading reports. The brown color is accompanied by other hues, such as pink or yellow, or the brown stones are treated to produce other colors.
The vast majority of the group (83%), weighed less than one carat, with 56% of them being under one-half carat. The dominant shapes were round (24%), pear (20%), rectangle (16%) and cushion (13%).
The research ‒ the most extensive ever carried out on pink and associated colored diamonds ‒ found that 25% are type IIa, which is much higher than with colorless to near-colorless diamonds (where the percentage is < 5%), Breeding said.
The majority of type Ia pink diamonds (diamond containing clusters or aggregates of nitrogen atoms as impurities in the crystal lattice) almost exclusively come from two sources: Australia’s Argyle mine and Russia, which also happen to be the most prolific and consistent producers of such stones. Type IIa pink and other type Ia pink diamonds come from other sources – such as Tanzania, South Africa, and Brazil – but there is no reported regular production from any mine.
“It’s unusual that these types are from very specific locales, especially because they are so rarely found in other sources,” Breeding noted, adding that because Argyle is the dominant source for highly saturated (colored) pink, purplish-pink and red diamonds; the decline in the numbers of such stones will be substantial after the mine closes next year.
Research Aids Automated Detection of Treatment/Lab Growns
This pink diamond study enables GIA to better understand how these rare and beautiful diamonds formed and the properties that give them their color. The researchers found many new details at the atomic level by analyzing the absorption spectroscopy and photoluminescence data. These findings add to the understanding of these amazing stones – which can enable faster, more accurate identification.
The research from this study reinforces GIA’s development of an upgrade for the GIA iD100® gem testing device that adds a function to accurately screen pink and related color diamonds for treatments and synthetics. @chapter:41 @chapter:1 @chapter:41


# Publication Year: 2021
# Title: Exquisite Opal Strand
# Abstract: This spectacular opal strand displayed unusually bright, vibrant play-of-color across all 28 beads. Photo by Angelica Sanchez.
The Carlsbad laboratory recently received for identification a strand of 28 graduated round gray beads displaying spectacular play-of-color (see above). At the time of inspection, the strand weighed 115.5 grams total. Standard gemological properties were consistent with opal. All 28 beads had a spot RI reading of approximately 1.39 and fluoresced very weak yellow under short-wave UV and weak yellow to long-wave UV. No indications of dye, color treatment, clarity enhancement, or coating were present. All of the beads showed a natural play-of-color phenomenon under microscopic examination. A single drop of water was placed on the surface of each bead and observed under direct transmitted light in brightfield mode in the microscope. Each bead absorbed the water, revealing them to be porous. Therefore, it was concluded that all 28 beads were natural hydrophane opal with natural color. Crazing was not observed in any of them.
Hydrophane opals are porous enough to absorb water, which can cause a change in appearance and a temporary increase in weight. It is therefore not advisable to immerse them in water (Fall 2013 Lab Notes, pp. 175–176).
This opal strand was remarkable due to the unusually bright and vibrant spectral play-of-color seen evenly across all 28 beads. Play-of-color in precious opal is caused by light interacting with stacked submicroscopic silica spheres. Light waves bend as they pass between these spheres, causing the light to diffract into the spectral colors of the rainbow. The resulting color is determined by the size of the spheres. For example, approximately 0.1 micron spheres produce a violet color and approximately 0.2 micron spheres display a red color (https://www.gia.edu/opal-description). @chapter:48 @chapter:0 @chapter:48


# Publication Year: 2016
# Title: Unusual Colored Stones
# Abstract: These rare gemstones were recently examined at GIA’s Carlsbad laboratory. From left to right: a 0.87 ct green adamite, a 0.73 ct brown bahianite, a 42.08 ct light brownish yellow cerussite, a 0.33 ct purple chambersite, a 2.45 ct orange olmiite, and a 1.30 ct color-change remondite. Photo by C.D. Mengason.

	Recently, a parcel of approximately 40 rare gemstones was submitted to GIA’s Carlsbad laboratory for identification. Six of these stones represented gem types that had never been examined at this location. They were identified using standard gemological testing, Raman spectroscopy, and energy-dispersive X-ray fluorescence (EDXRF).

	A 0.87 ct translucent green hexagonal step cut was identified as adamite, Zn2(AsO4)(OH). It had a specific gravity (SG) of 4.40 and a refractive index (RI) of 1.721–1.750. The stone fluoresced weak green under long-wave UV light but was inert to short-wave UV, which is atypical of adamite. Clouds and fractures were observed with 30× magnification.

	A translucent brown trapezoidal step cut with an SG of 5.18 proved to be bahianite, Al5SbO14(OH)2, which is especially rare as a facet-grade gemstone. The 0.73 ct bahianite had a refractive index over the limit (OTL) of the RI liquid. It was inert under long-wave UV light but displayed very weak blue under short-wave UV light. Large fractures, along with numerous whitish fibrous, radial, and granular inclusions and some surface-breaking opaque metallic inclusions, were visible using 30× magnification. It also displayed vitreous to subadamantine luster.

	A 42.08 ct transparent light brownish yellow octagonal mixed-cut specimen with an SG of 6.54 displayed an OTL refractive index and a biaxial optic figure, indicating its doubly refractive nature. It was inert to long-wave UV light but fluoresced very weak yellow under short-wave UV light. Magnification revealed strong doubling, strong fire, and numerous growth tubes and needles. Its heft was high due to its lead content. These properties, along with advanced testing, led to its identification as cerussite, PbCO3. Although cerussite is a common weathering product of lead ore minerals, its softness, brittleness, and heat sensitivity make it a very rare faceted gem, particularly in this large size.

	Another stone from the collection, a 0.33 ct transparent to semitransparent purple triangle step cut with an SG of 3.49 and an RI of 1.728–1.734, was determined to be chambersite, Mn3B7O13Cl. The gem was inert to both long- and short-wave UV light and showed numerous clouds with 30× magnification. Chambersite is an extremely rare mineral, found as deep as 70 feet in salt brines (J.E. Arem, “Chambersite,” The Color Encyclopedia of Gemstones, 1987, 2nd ed., p. 65). Because it is so small and dark, this material is almost never faceted.

	A 2.45 ct semitransparent orange cushion modified brilliant was identified as olmiite, CaMn[SiO3(OH)](OH), which was first discovered in 2006 in South Africa (http://www.mindat.org/min-30762.html). Its SG was 2.95. The stone was doubly refractive, displayed an RI of 1.648–1.671, and fluoresced very weak orangy red under both long- and short-wave UV light. Magnification revealed wavy graining, fibrous dislocations and inclusions, and a slightly oxidized stone surface. Most olmiite crystals are not suitable for faceting.

	The final stone of the six, a transparent pear-shaped modified brilliant that changed from greenish yellow under fluorescent light to yellowish orange under incandescent light, was identified as color-change remondite, Na3(Ce,La,Ca,Na,Sr)3(CO3)5. The 1.30 ct stone had an SG of 3.40 and showed an RI of 1.628–1.631, yielding a birefringence of only 0.003. It was inert to both long- and short-wave UV light. Handheld prism spectroscopy revealed a strong rare earth element spectrum. Large growth tubes, scattered particles, and etch channels were observed with 30× magnification. The stone’s rounded facet junctions indicated a low hardness. Remondite was previously reported as a color-change burbankite-related mineral from Quebec (Winter 1992 GNI, pp. 270–271).

	Such a suite of gemstones, prized among avid gem collectors, is not often submitted to the laboratory. Without the help of advanced analytical equipment such as Raman spectroscopy and EDXRF to complement standard gemological testing, it would be challenging to conclude the identity of these rare gemstones. @chapter:3 @chapter:0 @chapter:3


# Publication Year: 1989
# Title: Fall 1989 Gem News International
# Abstract: Diamonds
            Increases in Diamond Sales
            Diamond Cutting in China
            Strained Relations between India and Australia
            Tests Under Way for Diamonds in Canada
            Australians Explore for Diamonds in the United States
            Joint Venture with DeBeers in Australia
            New DeBeers Mine in Namibia
Colored Stones
            Amethyst in Maine
            Amethyst Scepters from Malawi
            Amethyst-Citrine Update
            Fine Aquamarine from India
            Brazil Update
            Crystal Chandeliers Made by Nature
            Santa Terezinha Emerald Treatment
            Large Bicolored Sapphire
            Kanchanaburi Sapphires
            Underwater Treasure Hunt in Thailand
            Unusual Tourmalines from Brazil
Pearls
            Interesting Cultured Blister Pearl
Synthetics and Simulants
            Chinese "Jade" Update
            Imitation Opalized Shells
Announcements
            Tucson Gem & Mineral Show 1989
            Bangkok International Jewelry Fair
            Israel’s annual Showcase ‘90
            Bijorhca in Paris 1990
            Inhorgenta 90 in Munich
            Metal Media Juried Exhibition

To view the full section, download the PDF above. @chapter:34 @chapter:3 @chapter:34


# Publication Year: 1989
# Title: Grading the Hope Diamond
# Abstract: For the first time ever, the famous Hope diamond was graded by a widely recognized system. Although the 45.52-ct weight was confirmed, the GIA Gem Trade Laboratory graders found the clarity—recently reported as "apparently flawless”—to be VS1.  Color graded "fancy dark grayish blue,'' the Hope phosphoresces an exciting red to short-wave U. V. radiation. @chapter:22 @chapter:1 @chapter:22


# Publication Year: -
# Title: GIA Field Gemologists seek Ruby, Sapphire, and Spinel in Mogok, Myanmar
# Abstract: Seeking Mogok’s Hidden Gems

	Venture into Mogok’s deepest mines with GIA field gemologists.

	This video takes you deep underground with GIA’s Field Gemologists Vincent Pardieu and Dr. Aaron Palke as they explore the geology of Mogok’s ruby, sapphire, and spinel deposits.

	Mogok’s unparalleled reputation as the source of fine gemstones goes back more than 800 years. The Mogok mining area is about 400 miles (650 km) north of Yangon in a densely vegetated, mountainous area rising to 7,700 feet (2,347 meters) above sea level.

	This video shows the lengths GIA’s field gemologists go to in order to secure gemstone samples for research and provides a rare glimpse into some of Mogok’s deepest underground hard-rock mining operations. It documents their sometimes perilous descent down handmade ladders and via ropes and pulleys into the depths of some of these famous mines. At one point the intrepid gemologists are 1,200 feet (365 meters) below the surface. According to Pardieu, that deep descent into the mining operation in the Kadoke Tad area—where the group witnessed ruby mining—was the expedition’s highlight.

	Later, the markets and temples of Mogok township demonstrate the romantic allure and timeless appeal this location and its people have for so many gemologists and gem dealers. “There’s something absolutely amazing about Mogok,” offers Pardieu. “This place produces the best quality ruby, the best quality sapphire, the best quality spinel, the best quality peridot, probably in the world.”

	This GIA Field Expedition (FE62) took place in June 2014. Besides Pardieu and his cameraman Didier Gruel, the participants were two geologists, Dr. Gaston Giuliani, Director of Research at the Institute of Research for Development (IRD) in Nancy, France, and Dr. Aaron Palke, post-doctoral research associate at GIA in Carlsbad. @chapter:40 @chapter:0 @chapter:40


# Publication Year: 2022
# Title: Smithsonian’s Great American Diamonds Exhibit
# Abstract: Left: The 16.87 ct Freedom, from Kelsey Lake in Colorado, is the largest faceted diamond from the U.S. Right: The 12.42 ct Uncle Sam is the largest faceted diamond from Arkansas, cut from a 40.23 ct crystal uncovered at the Crater of Diamonds. Photo by James Tiller and Brittany M. Hance; courtesy of Department of Mineral Sciences, Smithsonian Institution.
Two extraordinary American diamonds (see above) have found a home at the Smithsonian’s National Museum of Natural History, where they were unveiled as part of the new Great American Diamonds exhibit in June. The 16.87 ct Freedom diamond, the largest faceted diamond of U.S. origin, was fashioned from a 28 ct crystal unearthed at Colorado’s Kelsey Lake mine in 1997. The cushion-cut diamond is now set in a ring donated by Robert E. and Kathy G. Mau. The second diamond on exhibit, the emerald-cut Uncle Sam, was faceted from the largest uncut American diamond crystal ever discovered at 40.23 ct. Uncovered at Arkansas’ Crater of Diamonds in 1924, the flawless 12.42 ct pinkish brown stone was recently recovered from a private collection (after being missing for decades) and donated by Peter Buck. This is the first time the Uncle Sam has been exhibited in more than 50 years.
While diamonds from the United States are exceptionally rare, the two mines in Colorado and Arkansas produced tens of thousands of carats of rough diamonds, from 1919 to 1926 at the Crater of Diamonds and 1996 to 2001 at Kelsey Lake. “Most people are surprised to learn that diamonds have been mined in the United States, and as the national museum, we are delighted to introduce these great American diamonds to our visitors,” said Dr. Jeffrey Post, the museum’s curator-in-charge of gems and minerals.
Joining these two impressive donations in the Great American Diamonds exhibit are two uncut diamonds from the museum’s existing collection. The Canary, a golden yellow crystal weighing 17.85 ct, is one of the largest uncut diamonds from Arkansas. The 6.45 ct Colorado, which displays the typical octahedral shape of a natural diamond crystal, was recovered from the kimberlite host rock during mining operations at Kelsey Lake. As part of the Smithsonian’s National Gem and Mineral Collection, these four stones are among more than 10,000 precious stones and pieces of jewelry, including the iconic Hope diamond. @chapter:34 @chapter:1 @chapter:34