# Publication Year: -
# Title: Exhibition Review: Van Cleef & Arpels at the Bowers Museum
# Abstract: This multi-colored Van Cleef & Arpels bracelet from 1924 is decorated with ancient Egyptian hieroglyphic motifs. It features buff-top emeralds, sapphires, rubies, pavé-set diamonds, and calibrated onyx. Most of the house’s Egyptian revival jewels, which were at the height of fashion in the 1920s, are clips or bracelets created between 1922 and 1925. From "A Quest for Beauty: The Art of Van Cleef & Arpels," courtesy of Van Cleef & Arpels.

	“A Quest for Beauty: The Art of Van Cleef & Arpels”
The Bowers Museum of Cultural Art in Santa Ana, California
Through Feb. 15, 2014

This multifaceted exhibit, which debuted at the Bowers Museum Oct. 27, features more than 200 jewels and fashion accessories, as well as design sketches and archival photos of celebrities and royalty wearing some of the finest jewelry ever assembled.

According to Tim Adams, the Bowers’ curatorial consultant of decorative arts, the exhibit was more than ten years in the making. The pieces are from the archival Van Cleef & Arpels Collection, which the company has assembled through auction purchases for preservation.

The exhibit begins with the 1895 wedding of Alfred Van Cleef and Estelle Arpels. Clusters of photos in the foyer show the founders, the company’s first shop on Place Vendôme in Paris, and boutique openings in fashion capitals across the world. A floor-to-ceiling timeline lists important milestones from 1895 to the present day.

View Gallery

	These images show pieces from the exhibit, "A Quest for Beauty: The Art of Van Cleef & Arpels."
Set to soft 1930s jazz, the exhibit follows a series of four defining themes: Nature, Elegance, Exoticism and Feminism. “Nature” examines the unique flora and fauna motifs that have influenced much of the Parisian jeweler’s artistry. The Peony brooch featuring 700 Burmese rubies demonstrates the innovative Mystery Setting, patented in 1933. With this signature design, grooves cut underneath the gemstones allow them to slide along rails, concealing the metal mountings.

As Adams points out, “They lose half the rubies they work with in a Mystery Setting. First they have to find all the rubies that match in color, then calibrate-cut each one. When you slide and snap the rubies into place, they tend to break. You lose three-quarters of the emeralds. It can take one or two years to complete one of these pieces.”

The “Elegance” theme is epitomized by the Minaudière line of Art Deco vanity cases. Accented with platinum, gold and diamond, the black lacquer case’s compartments hold the essentials of a 1930s woman: mirror, lipstick, powder, cigarettes and dance cards. This themed section also features yellow gold and platinum pieces with the luxurious feel of fabric, including lace clips and the distinctive Zip necklace. Since its debut in 1951, this V-shaped zipper necklace has been one of the company’s iconic designs.

“Exoticism” brings to life Van Cleef & Arpels’ fascination with faraway cultures, which began during the Egyptian revival of the 1920s. On display are baroque Indian motifs and Chinese-inspired pieces such as the black and red enamel Dragon clip. The “hippie” era of the 1960s and ’70s saw the return of exotic elements in the jeweler’s designs.

At the heart of “Femininity” are weddings and coronations. These include the wedding set of Princess Grace Kelly of Monaco and a replica of the 1967 coronation crown of Iran’s Empress Farah Pahlavi. (For political reasons, the original tiara could not be brought back to Paris.) Archival photos from the various estates complement this section, which also features pieces worn by socialite Barbara Hutton, opera diva Maria Callas and actress Elizabeth Taylor.

Adams notes that the use of LED lighting, rather than incandescent or halogen lighting, truly captures the beauty of the gemstones on display.

A final section is dedicated to Van Cleef & Arpels’ extraordinary craftsmanship. Each piece is created entirely by hand, using sketches and old-fashioned tools. Visitors can view panels dedicated to every painstaking step of the jewelry-making process, or sit down to a screening of “Les Mains d’Or,” a collection of nine short films offering a rare glimpse inside the storied Place Vendôme workshops.

From the Bowers Museum, “A Quest for Beauty” will travel to the Houston Museum of Natural Science in 2014 and the Art Institute of Chicago the following year. @chapter:20 @chapter:2 @chapter:20


# Publication Year: -
# Title: Hong Kong Show: Buyer-Seller Showdown on Prices
# Abstract: Buyers look over gemstones at the September 2015 Hong Kong Jewellery & Gem Fair last week. Photo by Russell Shor

	The September Hong Kong Jewellery & Gem Fair opened with some hard bargaining that had diamond and gemstone dealers hoping for deals.

	With the slowdown in China putting a drag on other Asian economies, expectations for this show, the world’s largest, were not high. But demand, albeit reduced, is there and retailers and jewelry manufacturers aggressively shopped for bargains from diamond dealers who had cut their inventories from very expensive rough and remain under intense pressure from their bankers to show a profit.

	The show is an important guide to how De Beers and Alrosa will conduct their final three sights/sales for the year.

	In August, De Beers cut its usual sight total by more than half to a reported $250 million and lowered prices by an average of 9% − concentrated mainly in medium- to better-quality goods that would polish out to between 0.30 carat (ct.) and 0.75 ct., where inventory levels are highest. And Alrosa, the world’s largest diamond producer by volume, followed suit, cutting volume and prices by similar amounts at its September sale.

	The results of the Hong Kong show will surely determine whether or not these two producers, which account for more nearly three quarters of the rough market, resume “normal” sales or continue to rein in supplies.

	Reports from state of Gujarat, India where the vast majority of diamond manufacturers are located, say many of those facilities have cut workers’ hours by as much as 40% because of reduced demand and high inventories, while an estimated 20,000 to 30,000 (5-7% of the workforce) have lost their jobs.

	Gujarat’s government is worried that the troubles in the diamond industry could exacerbate the existing unrest from the Patel community, which is demanding a larger share of government and academic jobs. A significant percentage of the diamond workforce belongs to this group, which had been one of the most prosperous in the region.

	Demand for emeralds remains robust. Gemfields achieved strong prices at its September auction of rough from its Kagem Mine in Zambia. The Singapore sale of 600,000 carats realized $34.7 million, for an average price of $58.42 per carat – the third highest total in the six years since the company has been auctioning Kagem material. This auction included finer quality material of various grades. The company also sells lower quality material, which is classifies as beryl, in separate sales.

RETAIL

	U.S. retail analysts were heartened by August’s improved job report and a very strong upward spike in the Conference Board’s Consumer Confidence index. The index, which had declined to 91.0 in July, rose more than 10 points to 101.5 in August as consumers grew more upbeat about the economy.

	“Consumers’ assessment of current conditions was considerably more upbeat, primarily due to a more favorable appraisal of the labor market,” said Lynn Franco, director of Economic Indicators at The Conference Board. “The uncertainty expressed last month about the short-term outlook has dissipated and consumers are once again feeling optimistic about the near future. Income expectations, however, were little improved.”

	De Beers’ executives remain “cautiously optimistic” about final quarter diamond jewelry sales.

	There are several reasons for their optimism regarding the U.S. One, the company is reviving its generic “Diamonds Are Forever” advertising campaigns it stopped several years ago. Some analysts blame lackluster diamond demand of the past five years on the ending of these campaigns.

	Second, the U.S. dollar has risen strongly among most major currencies, which helps keep prices stable here even if it does dampen demand in foreign markets. In China, for example, the diamonds from the August sight will cost 6% more because its currency declined by that much against the dollar in the past month. @chapter:37 @chapter:3 @chapter:37


# Publication Year: 1982
# Title: Some Observations on the Treatment of Lavender Jadeite
# Abstract: The separation of naturally colored lavender jadeite from color-treated material is a problem that has long plagued gemologists. One theory is that the dyeing agents being used are of an organic nature. If this is true, they should break down at elevated temperatures and lose their coloring ability. Naturally colored lavender jadeite, however, should retain its color and not bleach on heating. To investigate this theory, the author sawed 42 different specimens of lavender jadeite in half. One half of each specimen was heated while the other half was retained as a color control. Those stones that bleached on heating showed a strong orange fluorescence to long-wave ultraviolet radiation before heating and a moderate bluish-purple X-ray fluorescence both before and after heating. The control halves of those stones that retained their color when heated to as high as 1000°C fluoresced a very weak brownish red when exposed to long-wave ultraviolet radiation and a strong reddish purple to pink when exposed to X-ray radiation both before and after heating. @chapter:46 @chapter:0 @chapter:46


# Publication Year: 2005
# Title: Spring 2005 Gem News International
# Abstract: Tucson 2005
Colored Stones and Organic Materials
            AGTA Design Center Features Lapidary Art
            Amethyst from Georgia
            Amethyst and Citrine from Northwestern Namibia
            Aquamarine from Mt. Antero, Colorado
            Saturated Blue Aquamarine from Nigeria
            Carved Chalcedony Chain
            New Emerald Deposit in Xinjiang, China
            Gold-in-Quartz from Mariposa County, California
            Iolite from Northeastern Brazil
            Kyanite Widely Available
            Albitic “Moonstone” from the Morogoro Region, Tanzania
            A Faceted Pezzottaite from Afghanistan
            Tanzanite Marketing Initiatives
Synthetics and Simulants
            Manufactured Gold/Silver-in-Quartz
GNI Regular Features
Diamonds
            10.53 ct Gem-Quality Diamond from Saskatchewan, Canada
Inclusions in Gems
            Spinel in Aquamarine
            “Bamboo” Moonstone
            Pezzottaite in Quartz
Treatments
            Treated-Color Topaz from Pakistan
Conference Reports
            World Diamond Conference, Perth, Australia
Miscellaneous
            Burmese Faceted Rubies and the U.S. Import Ban
Announcements
            Gem-A Field Trip to Brazil
Exhibits
            Native American Jewelry at AMNH
            Pearls at the Milwaukee Public Museum
            Gems at the Hungarian Natural History Museum
            Cameos at the Met

To view the full section, download the PDF above. @chapter:4 @chapter:0 @chapter:4


# Publication Year: 2009
# Title: Characterization of “Green Amber” With Infrared and Nuclear Magnetic Resonance Spectroscopy
# Abstract: A peridot-like bright greenish yellow to green gem material called “green amber” has recently appeared in the gem market. It is produced by treating natural resin (amber or copal) with heat and pressure in two stages in an autoclave. Differences in molecular structure between untreated amber and copal as compared to treated “green amber” were studied by FTIR and 13C NMR spectroscopy, using powdered samples. Regardless of the starting material, the FTIR spectrum of “green amber” showed an amber pattern but with a characteristic small absorption feature at 820 cm-1. Solid-state 13C NMR spectroscopy of the treated material indicated a significantly lower volatile component than in the untreated natural resin, evidence that the treatment can actually “artificially age” copal. A new absorption observed near 179 ppm in the NMR spectra of all the treated samples also separated them from their natural-color counterparts.

	DATA DEPOSITORY

Photomicrographs
FTIR and NMR Spectra
Table DD-1: FTIR Spectral Features of Amber and Copal Before and After Heat Treatment
Table DD-2: Chemical Shift (ppm) of 13C NMR Spectral Features of Amber and Copal Before and After Heat Treatment
Parameters Used for NMR Spectroscopy
	Fall, 2009 @chapter:46 @chapter:0 @chapter:46


# Publication Year: -
# Title: Gems of Northern Madagascar Video with GIA Field Gemology
# Abstract: Madagascar is one of the great wonders of our planet. Wim Vertriest, Manager of Field Gemology at GIA, takes us on a journey back in time to understand how the island acquired its incredible gemstone diversity for which it is known today. He shares highlights from a recent field gemology expedition to two remote mines in Northern Madagascar: one a demantoid mine and the other, a sapphire mine. @chapter:51 @chapter:0 @chapter:51


# Publication Year: -
# Title: Holiday Pins: A Few of Our Favorite Things
# Abstract: A selection of holiday pins on display at the Richard T. Liddicoat Gemological Library at GIA in Carlsbad. Curated by librarians Chris Rogers and Rose Tozer. Photo by Kevin Schumacher/GIA

                      It’s that most wonderful time of the year: the lights, music and good cheer are on full festive display. For many jewelry lovers, a favorite way to celebrate the season is with a treasured holiday pin – or two, or more – front and center on a coat or sweater.

Rose Tozer, a senior research librarian at GIA in Carlsbad, has been known to wear more than a dozen at once to get display time for as many of the nearly 200 in her collection during the holiday season.

“My mother started me on them when I was in college. She would look at my outfit and say ‘you need a little pin’ and then she’d lend me one,” Tozer said. “The very first pin my mom gave me was an enameled snowman I would wear on my herringbone tweed overcoat.”

Holiday pins first came into fashion by way of “Art Deco masterpieces” in the 1920s and ‘30s, according to Kathy Flood, who has written several collectors’ guides, including “Comprehensive Jewelry Guide to Christmas Tree Pins,” published earlier this year. Homemade felt pins were popular during the Depression and holiday corsages were popular in the 1940s, but it wasn’t until the 1950s and ‘60s that holiday pins were mass-produced.

	A glittering clear crystal Swarovski tree and an authentic Weiss tree. The stone-on-stone construction of the Weiss tree makes it too complicated to copy, according to holiday pin expert Kathy Flood. Photo courtesy Kathy Flood
The most-purchased tree from that era was the Weiss candle tree design, said Flood, which was in stores for the 1962, ’63 and ’64 holiday season. “Available in three sizes, sometimes it feels like there wasn't an American child or man who didn’t buy one for their mother, teacher, girlfriend or wife,” she said.

Many holiday pins ‒ costume jewelry composed of plated, enameled metal, plastics or wood, all often ornamented with crystal stones ‒ were the creations of major jewelry houses such as Eisenberg, Trifari, Swarovski, Hollycraft and Weiss. Well-known individual designers and companies include Miriam Haskell, Stuart Freeman, Erickson Beamon, Robert Lee Morris, as well as couture names from Nina Ricci and Elsa Schiaparelli to Givenchy and Molyneux.

Even the highest-end names ‒ Bulgari, Cartier, Chanel and Belperron ‒ produced treasures in trees that are most coveted and prized.

“They are stunning arbors of precious metals and fine gems, loaded with design integrity,” Flood said. “These truffles of the jewelry world, on the occasions they turn up for sale, are hunted out at top auction venues such as Christie's and Sotheby's. Some trees have turned up on catalog covers for December sales.”

	This 1991 Christie’s auction ad features a Christmas tree pin of jade and other gems.
	Photo courtesy Kathy Flood
The Christmas tree – an iconic symbol of many people’s favorite time of the year – is the most popular pin motif, recreated a thousand different ways, said Flood, who trimmed her holiday forest down to 1,000 trees.

“It's surprising how much effort designers put into creatively portraying them,” she said. “They range from beautiful to funny, inspired to classic, wild to a snooze. Also, many collectors come to trees because their mothers loved them and collected, or they inherit a collection.”

Snowflakes, wreaths, bells, Santas, reindeer and snowmen are other holiday pin motifs.

“Probably every collection has a terrific St. Nick, beautiful bell, etc., especially when someone wants all of a house's designs, but most effort seemed to be put into trees, so, they are the wittiest, prettiest and were issued in more profusion, so there's more to choose from,” Flood said.

	Some of GIA librarian Rose Tozer’s most treasured pins include this tree and wreath
	from her mom’s collection. Photo by Kevin Schumacher/GIA
Tozer’s favorites – a wreath, tree and Santa – are the ones that once belonged to her mom.

“After she died, my sister and brother very generously let me have all of them,” she said. “My next favorite one would definitely be an Eisenberg Ice Christmas tree: all white glass. That was my first expensive pin ($48). I had buyer’s remorse for months! I bought it in August and not until I wore it in December did I relax about it! That is one I always make sure I wear.”

Treasure Hunts for Holiday Pins

The reasons jewelry lovers are drawn to collect holiday pins are as varied as their designs, but for many it is often an emotional connection.

Flood distinctly remembers when she discovered them at a hair appointment in November 1993. The salon owner handed her a glass of wine and the December issue of Vogue, which she happened to open from the back.

“If I hadn't, I never would have seen Candy Pratts Price's stunning “Last Look” page, with 18 of the most gripping holiday brooches ever designed,” Flood said. “It's hard to express the feeling I had when I saw them. They produced an intense aesthetic pleasure.”

	This plastic tree was created by Stuart Freeman for Vogue magazine. The trunk is made from real bark from Central Park. Photo courtesy Kathy Flood
“And amid the masterpieces by Bulgari, Cartier and Mme Belperron was a plastic tree wound with glittering jeweled garland and a trunk of real bark from Central Park,” she said. “That tree really penetrated my desire zone and I looked for its designer, Stuart Freeman, for a decade.”

Flood’s passion for the pins was strong enough, she knew she could get at least one book out of it. Research would be required – which conveniently paved the way to building a collection. Her background as a journalist helped her develop expertise in key areas, such as designers, manufacturers and the jewelry industry in general.

‘When I first began looking for Christmas trees, if you'd asked me how many different trees or designs there are, I would have guessed 50. Now I'd estimate closer to 5,000,” she said. “The first Christmas after I discovered the tree as collectible holiday pin, my husband bought five for me as gifts and thought, ‘Well, that's that. There can't be any more.’ That's the madness of it all: there are always more. One you've never seen, even after 21 years of forest ranging, suddenly springs up and you're like, ‘What?’”

Tozer, whose mom encouraged her to add a little sparkle to her coat, said she didn’t really become a devotee until she started to work at GIA in late 1989, “where most everyone has caught the jewelry bug.”

Since then, she’s found them everywhere: garage sales, antique/collector’s shows, the car wash (“truly, some of my best finds!”), department stores, stationery stores, the pharmacy.

	Tozer makes sure she wears this all-white-glass Eisenberg Ice Christmas tree every year.
	Photo by Kevin Schumacher/GIA
“Usually when I’m not looking for them is when I find them,” she said. “When I started collecting, I refused to pay more than $10 for a pin. After all, I really only wear the pin once. I was pretty successful for a long time holding to that amount but it’s hard to find them that cheap anymore. I’ve now bumped that up to no more than $40.”

Flood, who lives in St. Louis, Missouri, said one of her most thrilling buys was the unopened Christmas tree pin inventory of a drugstore in the Southeast.

“It was the old-time kind of drugstore that carried all sorts of wonderful goodies,” she said. “The owner, who must have died suddenly and the store closed, had ordered gorgeous tree pins by Laguna, made in Austria. They were all still boxed, on their original velvety green cards and wrapped in crinkly brown paper stamped Austria all over. It's one of the all-time great trees.”

Sometimes, however, just the experience of hunting the pins can be almost as fulfilling as coming home with one.

“We walked into an antiques shop on Cherokee Street in St. Louis during the holidays,” Flood recalled. “The proprietress was engaged in an overly long conversation with a customer, so we decided to leave,” she said. Before they got out the door, however, she called out to them and Flood asked if she had any Christmas pins.

“She glared at me in a rude and suspicious way. It turns out she was a major collector of Christmas tree pins and thought I was pulling her leg. I had no idea,” Flood said. “She started pulling out tray after tray of the best trees from under the counter. All hers; none for sale.”

They got together every year during the holidays, and even traded trees. Then one year, the shop was boarded up, and Flood learned the woman had died.

Flood did fulfill a decade-long pin quest when she finally found Stuart Freeman, designer of the Christmas tree with real bark in that 1993 Vogue. The whole experience came full circle in 2014 when Freeman had lunch with editor Candy Pratts Price, who originally created the page that launched Flood in this collecting sphere.

“Stuart got a photo of Candy in the cafe, holding up my book. It was almost as thrilling as hearing Stuart say, when I first found him, ‘Yes, I think I have a few of my Vogue trees left in storage,’” she said. “That was a cue-the-medics moment!”

The Richard T. Liddicoat Gemological Library in Carlsbad is home to thousands of books, journals, videos and images on gems and jewelry. GIA librarians often use those resources to create displays on a specific theme to encourage students, staff and visitors to learn more about a topic. @chapter:28 @chapter:2 @chapter:28


# Publication Year: 2018
# Title: Cultured Pearl Update
# Abstract: Figure 1. The pearl market has seen a rise in popularity in pieces with unusual color (left) and size combinations (right). Photos by Kevin Schumacher.
We had the opportunity to speak with Fran Mastoloni (Mastoloni Pearls, New York) at the AGTA show and hear his thoughts on the current status of the cultured pearl market.

According to Mastoloni, pearls continue to do very well. His company had one of its best fourth quarters in recent history, and he believes that has much to do with the pearl cycle. He noted that pearls tend to be in fashion in seven-year periods. Mastoloni believes this is the second year of a seven-year trend. Last year pearls were making a resurgence, but instead of classic white pearls they were selling unique and fashionable pieces, such as the cocktail necklaces of white South Sea, gold Philippine, and silvery Tahitian pearls seen in figure 1, left. Mastoloni explained that customers are enjoying the organic shapes and colors of these different varieties and how versatile such necklaces and pieces can be. This trend has continued into 2018, but they are selling these unusual combinations to designers and major manufacturers rather than individual stores. These clients are incorporating Tahitian or keshi pearls or stations into necklaces, as well as Mastoloni’s colored pearl palette, with their own design elements. Mastoloni also noted a greater use of keshi pearls as stations, with one designer planning to use a bezel-set light sapphire between the stations to create something different, fun, and marketable.

Fran Mastoloni’s Cultured Pearl UpdateFran Mastoloni talks about the current state of the pearl market, and shows us some of his most popular necklaces.
Fine pearls continue to sell, though with a twist. Mastoloni’s top sellers include white South Sea, Indonesian, and Australian pearls in classic styles such as long necklaces, but with a more organic appearance. The price point is very important, Mastoloni said, because a number of customers self-purchase for work or to satisfy their own tastes. In fact, he has found that self-purchasing of pearls has become more popular than gift giving. Pearls are versatile and can be worn anywhere, he said, because they communicate that the wearer is confident but not ostentatious.

Mastoloni showed us two graduated Japanese akoya necklaces that appear to date from the 1970s or ’80s. The pearls measure 7.5 × 10.5 mm and are perfectly matched, with no imperfections and a nacre coating that is just not seen anymore; he has three other strands that are slightly smaller. These sizes are “almost unheard of” in akoyas and make for an unusual addition to a collection. He also showed his “cloud” necklace (figure 1, right), one of his most popular, created from Chinese tissue-nucleated pearls. Chinese pearls are sold by weight, and the cultivators are using larger nuclei to create larger pearls. Since pearls are no longer grown in the sizes used in this necklace, this material is unlikely to be found on the market despite its popularity. @chapter:56 @chapter:2 @chapter:56


# Publication Year: 1998
# Title: Spring 1998 Gem News International
# Abstract: TUCSON ‘98
Diamonds
            Gem Crystals from Russia and China
Colored Stones and Organic Material
            Andalusite (Chiastolite) Sphere
            Coral with a Blue Sheen from Alaska
            Bicolored Corundum
            Emerald from Tocantins, Brazil
            Spessartine Garnet from Madagascar
            Sphene from Madagascar
            Spinel from Vietnam
            Parti-Colored Faceted Liddicoatite Tourmaline
            Another Tourmaline Source in Namibia
Synthetics and Simulants
            Synthetic Amethyst Grown Over Round Seeds
            “Glass stones”: Imitation Agates
            Synthetic Moissanite from Russia
Instrumentation and Techniques
            Buff-Top Faceted Stones Cut from Quartz Spheres

MORE FROM THE 26TH INTERNATIONAL GEMMOLOGICAL CONFERENCE
Colored Stones and Organic Materials
            An Unusual Organic “Gem”: Bezoar
            Gem-Quality Transparent Feldspar from North America
            Libyan Desert Glass
            Maw-Sit-Sit from Myanmar
            An Opal Nomenclature
            Identifying Natural Opal in the Field
            Kashmir Rubies
            Gemstones of Switzerland
Synthetics and Simulants
            First Commercial Synthetic Ametrine from Russia
Instrumentation
            Cathodoluminescence and Photoexcitation Applications in Gemology

Announcements
            New Geologic Maps of Sri Lanka
            Nature of Diamonds Exhibit Extended
            International Mineralogical Association Meeting
In Memoriam
            Charles E. Ashbaugh III, 1944-1997
            Eugene Edward Foord, 1946–1998

To view the full section, download the PDF above. @chapter:2 @chapter:0 @chapter:2


# Publication Year: 2014
# Title: Mixed-Type HPHT Synthetic Diamond with Unusual Growth Features
# Abstract: Figure 1. These growth tube features were visible through the table of the HPHT-grown synthetic diamond. Photomicrograph by Troy Ardon; magnified approximately 90×.

A 0.28 ct round brilliant was submitted as synthetic moissanite to the Carlsbad lab for an identification report. At first glance, synthetic moissanite seemed like a possibility. The stone had a green-yellow color and contained numerous growth tubes visible through the table (figure 1). Yet it did not show doubling in the microscope, which is a characteristic feature of synthetic moissanite. Its infrared spectrum was a match for diamond. The infrared spectrum also showed a very unusual combination of boron and nitrogen impurities at 2804 and 1130 cm–1, respectively (figure 2). These two impurities are not known to occur together in natural diamonds in measurable quantities. This was a strong indicator of synthetic origin. A DiamondView image (figure 3) confirmed that it was synthetic, grown by the high-pressure, high-temperature (HPHT) method. It is noteworthy that after the sample was removed from the DiamondView, it showed very strong blue phosphorescence that was clearly visible in ambient room lighting and persisted for several minutes.

Figure 2. The HPHT-grown synthetic diamond’s infrared spectrum shows peaks related to both boron and single nitrogen.

Figure 3. This DiamondView image shows the characteristic growth pattern of an HPHT synthetic diamond. Image by Troy Ardon.
Unless special precautions are taken, diamond synthesis will incorporate nitrogen into the lattice, which leads to a yellow bodycolor. Certain chemicals can be added to prevent the incorporation of nitrogen, and this can lead to colorless diamonds. If boron is introduced to the growth of synthetic diamonds, it will become incorporated and produce a blue bodycolor. If both boron and nitrogen are allowed to incorporate into the lattice, the blue and yellow bodycolors will combine to produce a green color (J.E. Shigley et al., “Lab-grown colored diamonds from Chatham Created Gems,” Summer 2004 G&G, pp. 128–145). Since boron is an electron acceptor and nitrogen is an electron donor, an excess of boron will compensate the nitrogen and the blue color will predominate. Because nitrogen and boron have slight preferences for different growth sectors, if the concentration of both nitrogen and boron is carefully controlled, nitrogen and boron will dominate different growth sectors. The colors will blend to create a face-up greenish color (R.C. Burns et al., “Growth-sector dependence of optical features in large synthetic diamonds,” Journal of Crystal Growth, Vol. 104, No. 2, 1990, pp. 257–279).

The growth tubes in this sample were an unusual feature, last seen in a selection of HPHT-grown synthetics several years ago at GIA’s West Coast laboratory. They appear similar to synthetic moissanite growth tubes, though there are a few key differences. Whereas the growth tubes occur in only one direction in synthetic moissanite, they could be seen growing in different directions in this synthetic diamond. The tubes in synthetic moissanite also tend to be very straight, while the ones in this sample curved and changed direction. Although this stone bore some superficial resemblance to moissanite, its gemological properties were quite different, another reminder to avoid quick sight identifications. @chapter:9 @chapter:1 @chapter:9


# Publication Year: 2013
# 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 southern 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 color centers occurring in natural zircon.

Electron paramagnetic resonance (EPR) and optical absorption spectroscopy are used on a heterogeneous sample group of 11 small untreated zircon crystals. The findings indicate an obvious correlation between color and certain paramagnetic defect centers in the crystal structure. But 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), as well as the intricate substitutional charge patterns that reflect the isomorphism of zircon.

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

The results confirm that these two common color series subdivisions are meaningful.

Abstracted by Edward R. Blomgren @chapter:10 @chapter:0 @chapter:10


# Publication Year: -
# Title: Turquoise Care and Cleaning Guide
# Abstract: Turquoise ranks 5 to 6 on the Mohs hardness scale.

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

Turquoise ranks 5 to 6 on the Mohs scale and its toughness is generally Fair to Good.

Stability
Turquoise is generally stable to light, but high heat can cause discoloration and surface damage. It dissolves slowly in hydrochloric acid, and it can be discolored by chemicals, cosmetics, and even skin oils or perspiration.

Cleaning
It’s safe to clean turquoise jewelry with warm, soapy water, but it should never be cleaned with steam or ultrasonic cleaners. Some turquoise is treated to improve its surface appearance. Heat or solvents can damage the treated surfaces. @chapter:16 @chapter:0 @chapter:16


# Publication Year: 2007
# Title: Fall 2007 G&G Lab Notes
# Abstract: Large Cat’s-Eye Aquamarine
Dyed Blue Chalcedony Detected by UV-Vis-NIR Spectroscopy
Historic “Piggyback” Diamond
Natural Type IIb Blue Diamond with Atypical Electroluminescence
An Unsuccessful Attempt at Diamond Deception
Kyanite Resembling Blue Sapphire
Phenakite as a Rough Diamond Imitation
Glass-Filled Synthetic Ruby

To view the full section, download the PDF above. @chapter:43 @chapter:1 @chapter:43