# Publication Year: -
# Title: From the Andes to the Pantanál: In Search of Ametrine
# Abstract: Before preforming, ametrine is often examined under a bright light to reveal the best purple/yellow orientation of the rough for subsequent cutting.

Introduction
The highest peaks of the Andes Mountains tower majestically over Bolivia. At over a million square kilometers, an area twice the size of Texas, this country occupies a fairly large share of central South America. The Andean mountain chain, known as the Cordilleras, lie in the eastern third of the country, and the majority of Bolivia’s ten million people live here, as they have since pre-Columbian times. Even after the Spanish conquistadores laid claim to this rich and beautiful land in the early 1500s, the Andes remained the country’s lifeblood.

	Most of Bolivia’s ten million people live in the Andes Mountains. The Huayna Potosi mountain is located just north of La Paz.
We bring you to the source of one of the world’s most unique gems: ametrine. In this gem, nature has combined two quartz varieties, purple amethyst and golden citrine. Ametrine is found only in this exotic Andean nation, a land as unique as the gem it produces.

	This 44.00 ct ametrine features concave facets that combine to mix the color of the purple and gold, producing a beautiful effect. Courtesy of Minerales y Metales del Oriente.
The goal is to better understand ametrine and its origin, as well as the people who mine it and treasure it.  We’ll take you to the Anahí mine itself, getting our hands dirty as we clamber through the very tunnels and shafts that pierce the earth’s crust to produce this unique gem material. There you will see how the ametrine gets transported and processed, and then the final act of making the gem ready for jewelry. Finally, we’ll take you to a glamorous showroom in Bolivia that specializes in selling these treasures. In all, you will have a true mine-to-market experience.

But our journey through Bolivia begins high in the Andes—far from the tropical environment that produces ametrine.

	Huayna Potosi mountain and Lake Titicaca.
Bolivia’s Highlands
Bolivia’s highest peak, El Nevado de Sajama, rises 21,400 feet above sea level and remains cloaked in a permanent snow bank, as do many of the other impressive peaks in the Andean Cordilleras. It is the snows from the Western and Central Cordilleras that nourish Bolivia. The melt-off rushes down the mountains toward the Altiplano, a high plain that is home to the world’s highest navigable body of water, Lake Titicaca. It is also the largest freshwater lake in South America, and visible from outer space, and home to fascinating, high-altitude flora and fauna such as the James flamingo, once thought to be extinct before it was rediscovered in the mid-1900s.

The roots of Bolivia’s history—and the bulk of its population and cultural and mineral riches—lie in these high, austere elevations of the Altiplano. In this arid, seemingly inhospitable location, the mighty Tiwanaku civilization once thrived. Tiwanaku is thought by historians to be a precursor to the mighty Inca empire, and its people inhabited the region around Lake Titicaca as early as 1500 BC. Evidence suggests a civilization dedicated to agriculture. At the height of the civilization, around 300 BC, this region was likely the source of many of the world’s potato varieties, as well as unique forms of barley and quinoa and domesticated camelid species such as the llama, vicuña and alpaca. The people were also exceptional stonemasons. A visit to Tiwanaku, Bolivia’s most important archaeological discovery and a UNESCO World Heritage Site, exemplifies their extraordinary architecture and stone carving for decorative or ceremonial purposes. One of the most important icons there is the Puerta del Sol (Gate of the Sun), a giant monolith carved with a stunning design of the sun god Inti wearing an elaborate headdress and surrounded by humanlike birds.

	At Tiwanaku, Bolivia’s most important archaeological site, lies Puerta del Sol ("gate of the sun"). This ancient pre-Colombian rock monolith depicts the sun-god "Inti" which is  Bolivia's principal icon.
While Bolivia’s rivers and high-altitude lakes are nourished by the Andes, so are its people. In fact, the bulk of Bolivia’s population is concentrated in the Andean region. In the 1500s, the Spanish began to inhabit and colonize these areas, often returning to Europe with raw materials found in the New World. From mineral-rich Bolivia (known at the time as the Great Colombia), silver, gold and other treasures were taken in huge quantities. These contributed greatly to the growth of the Spanish Empire in the 1500s and 1600s.

	A Bolivian llama herder in the Antiplano region.
Potosí
If we see ametrine as a colorful reminder of Bolivia’s gem and mineral riches, it was precious metals, particularly gold and silver, that were most sought in the 1500s and 1600s. The city of Potosí epitomizes the treasures that pour out of the Andean region. An interesting story relates the discovery of silver in the year 1544. Huallpa, an Incan llama herder, had lost one of his animals, and rather than return home without it he spent the night on the mountainside. With the perpetual cold at this altitude, even more so once the sun sets, Huallpa built a fire to stay warm. As the legend goes, tiny threads of molten silver began to flow in small rivulets from under the coals, a mother lode of silver.

	The city of Potosi produces much of the world’s silver. Cerro Rico lies in the background.
For nearly 500 years since this discovery, Cerro Rico has been the world’s largest silver deposit. It is also one of the highest working mines in the world, located a punishing 14,000 feet above sea level. Of this discovery it was once remarked that a bridge of solid silver could be built, stretching from Potosi to Spain. This was figuratively true, as much of Cerro Rico’s wealth went directly to Spain in the following centuries. In attempting to create a Bolivian silver industry in the 1500s, the Spanish viceroy built the national Bolivian mint, La Casa de la Moneda. This truly imposing structure struck most of South America’s silver currency, as well as some of Spain’s own currency, for well over two centuries.

	Courtyard of La Casa de la Moneda, Bolivia’s national mint since the 1500s.
A rare view from the roof of La Casa de la Moneda today portrays a city whose architecture has remained virtually unchanged for the past 500 years. A series of colonial churches, brick and stucco buildings with red tile roofs, huddle together as if seeking warmth against the cold, barren landscape.

Overlooking Potosí is the now heavily pockmarked mountain of Cerro Rico, often depicted in Bolivian paintings as a sacred figure protecting the city and its people.

The Legend of Anahí
Bolivia’s colonial era is a good time to introduce the legend of Anahí, which touches upon the gem ametrine. The Spanish conquistadores were likely sending teams of explorers throughout the Andes starting in the 1500s, and their journeys led them down the high valleys into the lowlands and eventually the Amazon basin. Their charge was to discover as much gold and silver as possible for the homeland. One such explorer is said to have encountered a native Ayoreo tribe along the Pantanál region and, in a Pocahontas-like story, fallen in love with Anahí, an Ayoreo princess. As a token of her admiration for the conquistador, she presented him with a bicolored gem, one the Spaniards had never seen before. The rare stone was found near the village, in a mine that bears her name today.

As laced with romance as the story might be, the ametrine as know it today likely came much later, in the 1970s.

Sucre and La Paz
Bolivia’s constitutional capital is Sucre, located in the high mountain valleys. And while the city is one of the country’s largest, bustling with activity, it is no longer the seat of government. All the major government offices, the president’s home, and the international embassies are now located in La Paz. Nonetheless, Sucre is a magnificent colonial city to visit because of the wonderful mix of modern conveniences and ancient history blended together there. Sucre is centrally located, linked by railroad to Bolivia’s principal silver and tin mines, and from there to other main cities and export centers.

	In the Andean village of Tarabuco, many still wear leather replicas of old conquistador helmets.
Not far from Sucre is the village of Tarabuco, today a quaint community known for the amazing color and quality of its textile designs. But Tarabuco’s reputation was not always so peaceful. The Tarabuqueños were fierce warriors, ancestrally linked to the Incas and vigorously opposed to Spanish rule. A visit to the small town reveals a society lost in time, and one still gets an uneasy sense that outsiders are unwanted. The main square has as its centerpiece a ferocious Tarabuqueño statue, a wild-eyed man who has just ripped the heart out of a Spanish soldier’s chest. Despite their opposition to the Spaniards, the conquistadores clearly left their mark. Remarkably, vestiges of ancient Spanish influence are still seen centuries later. To this day, men and women often wear leather replicas of the old conquistador helmets, sometimes adorned with flowers.

La Paz, meanwhile, is truly international, the highest major city in the world. Here too the Bolivian partiality for hats is seen everywhere you go. In the La Paz region, the hats take on a more European flair. Women enjoy wearing black and brown felt hats, similar in style to an English “bowler” hat. The city a Bolivian woman comes from can often be determined from the type of hat she wears.

Overlooking La Paz is one of Bolivia's most dramatic mountains, Mount Illimani, which is permanently blanketed in snow and towers over the capital. Nestled in a deep bowl on the Altiplano, La Paz lies within easy reach of Lake Titicaca and Bolivia’s other main cities. A short but hair-raising drive to the cumbre, the highest mountain pass, some 20 miles outside the city, provides a bird’s-eye view of the city’s skyscrapers. Peering down the other side of the mountain, however, brings into view a precipitous plunge into the beginnings of Bolivia’s jungle lowlands. We will now proceed past the high valleys, following the melting snows and rivers into the jungle below, in search of ametrine.

Getting There
A half-hour flight from La Paz deposits visitors in the fast-growing city of Santa Cruz, in Bolivia’s tropical heartland. We are one step closer to the birthplace of ametrine. Our first stop in Santa Cruz is a visit with Ramiro Rivero, owner of Minerales y Metales del Oriente. This parent company encompasses a group of companies dedicated to mining, transporting, sorting, preforming, faceting and marketing all of Anahí’s gems. While ametrine is the most coveted gemstone, the mine also produces a variety of other quartzes, including amethyst, citrine, and colorless and lavender quartz.

The best way to get to Anahí is by invitation. Given the utter remoteness of the locality, those arriving unannounced are not welcomed with open arms. Assuming that an invitation stands, the travel choices are limited. In practical terms, there are really only two ways to get there: the drive and boat ride, or the flight from Santa Cruz. One could take the route of the conquistador and traverse miles of scrub brush and deep jungle by horse—which is not recommended. Another option would be to wait until the dry season (Bolivia’s winter months, such as June or July) and take the daylong drive along a rural road from Santa Cruz. The road meanders southeast to the village of Roboré, and from there to the town of Puerto Suarez, on the border with Brazil. This completes the land portion of the journey, approximately two-thirds of the way to the mine. An extraordinary network of swamplands and inland waterways, which make up the world-famous Pantanál ecological reserve, are the next leg of the trip. Another 8 to 10 hours are spent on a barge or motorboat, heading due north until reaching Laguna Mandioré, a large freshwater lagoon. Along its shores, a small port serves as a disembarkation point… and then for the last bumpy hour of the trip, a winding slog through the jungle, over a small series of hills to Anahí.

	This aerial photo shows the area near the Anahí mine in southeastern Bolivia. The mine is near the center of the shot, barely visible amid the foliage between the two mountains.
The most expeditious way to the mine is by single-propeller aircraft, a three-and-a-half hour flight from Santa Cruz. Not far from the mine, a grass airstrip awaits, and heavily armed guards are there to greet you.

	A single-propeller aircraft lands on the airstrip at Santa Cruz, near the Anahí mine.
Anahí
Upon reaching the mine, it becomes immediately clear that the place is all about quartz. Chunks of different sizes, including outright hexagonal crystals, are embedded along the road leading to the mine and throughout the mine itself. The hills surrounding the mine property consist of dolomitic limestone, containing veins of quartz. Several different shafts have been drilled into the property along these veins, and Rivero estimates that in a good year 3,000–3,500 kg of gem-quality quartz are mined. Ametrine is the most lucrative of the products, though on average amethyst makes up 44% of production by weight, ametrine 33%, and citrine 23%. A portion of the production is very light, lavender-colored, which Rivero has called “anahíta.” Some colorless or very milky quartz, previously discarded, is now retained for ornamental purposes.

	Fernando Arrien of Minerales y Metales del Oriente examines some large amethyst specimens at the Anahí mine.
In a good year, some 70 to 100 individuals work at the mine. Rivero takes great pride in describing how the mine is run. He says the miners play soccer every day, eat good food, watch satellite television, and use the company’s phones to call home. Alcohol is prohibited at the mine, and the company provides basic medical care.

	This 80.30 ct ametrine fantasy cut is courtesy of Minerales y Metales del Oriente.
The Mining Process
Most of the mining at Anahí takes place underground, accessed through a series of reinforced shafts and horizontal tunnels that extend to the mineralized areas. But there is also a small open-pit mining area. In the tunnels that are being enlarged, or when mineralized areas in the open pit need to be loosened for hand digging, dynamite blasting occurs once or twice per day. An alarm is sounded, and everybody seeks cover.

The air must be cleared after blasting, and then the miners remove loosened rock or chisel into areas containing amethyst. In the principal tunnels, overburden is piled into mining carts that roll down a slight grade when full. A single person pushes the carts. The overburden is transported up an elevator shaft and slid down a chute to another waiting mining cart in open air. Fully loaded carts are pushed to a washing area where the material is dumped. A water cannon further loosens agglomerations of rock and mud, and a series of sieves are used to separate out particulate matter. The Anahí mine is conscious of environmental damage from particulates, particularly if these were to flow downstream into the Pantanál. Particulates are therefore meticulously collected in a series of holding ponds.

	Mining operations at the Anahí mine.
After washing, material is bagged and taken to a protected presorting facility. Here some 20 employees begin evaluating the material. Some items are hammered—or cobbed—to reveal only facetable material, and to reduce weight. While no items are actually faceted at Anahí, the presorting is aimed at streamlining the cutting process later.

The mine prides itself on compliance with government regulations on the use of dynamite. Miners also wear protective gear such as hardhats, gloves (quartz can cut as easily as broken glass), eye protection, and masks to protect the wearer from airborne quartz particles.

The return trip is also arduous. Mine run is trucked to Laguna Mandioré and loaded onto a barge. From there it makes the long journey down to Puerto Suarez, where it is transported to a holding facility. Rough material is then shipped to the processing plant in Santa Cruz— as needed.

	This worker is prewashing the rough that comes out of the mine. Sediments of varying weight are collected in holding ponds to prevent water contamination downstream of the mine.
The Manufacturing Process
The main facility for processing the mine run and transforming the material into sparkling gems is located at the Parque Industrial in Santa Cruz. Here the material is categorized and sorted further, dutifully routed to the proper preformers and cutters at the factory. Preforming reveals the ametrine’s color zoning, which allows a skilled cutter to determine the final outcome of the gem. He or she must also work to fashion the gems to perfectly fit the factory’s jewelry design, or according to the specifications of overseas manufacturers. Because the designers, preformers, cutters, and jewelers are all located under one roof, clear communication is needed. An informal open-door policy encourages this type of communication.

	This woman at the Anahí mine is combing and sorting the quartz prior to sending it to Santa Cruz for faceting or preparation for export.

	At Minerales y Metales del Oriente, the parent company of the mining group, cutters work in an organized environment and wear masks to avoid inhaling the silica dust created as they cut and polish stones.

	This young woman at Minerales y Metales del Oriente is sorting amethyst, ametrine, and citrine.

	At the Minerales y Metales del Oriente processing plant, ametrine is cut and polished and prepared for jewelry. These models produced by CAD/CAM are for mounting ametrine in jewelry.
End of the Line
Now the finished jewelry is finally ready for its ultimate destination, the market. While a portion of the rough and preformed amethyst, ametrine, and citrine production is slated for export to markets around the world, M&M’s own retail division stands as a profitable test market for selling finished products in a retail environment. M&M’s spotless showrooms in Santa Cruz serves as a forum for aspiring, as well as accomplished writers, artists and musicians, who are often invited to exhibit their work or perform at the store. In turn these guests respectively carry the message of Anahí throughout the country. This strategy has not gone unnoticed. Ametrine, also known as “Bolivianita,” is the country’s national gemstone.

	Minerales y Metales del Oriente’s retail division sells finished ametrine jewelry sourced from the company’s Anahí mine. This photo was taken inside an M&M showroom boutique.
Ametrine serves as a spectacular mine-to-market model for anyone seeking to elevate the status, market appeal, and value of a given gemstone. And in examining the source of this unique gemstone, we have gone further—to understand the culture, beauty, and historical background of Bolivia.

	 This 17.80 ct ametrine is a stylized briolette. Courtesy of Minerales y Metales del Oriente.

	This 48.90 ct ametrine with concave faceting was cut by Dalan Hargrave. Courtesy of Minerales y Metales del Oriente. @chapter:0 @chapter:0 @chapter:0


# Publication Year: 2015
# Title: A New Natural-Color Bluish Green Chalcedony
# Abstract: Figure 1. This bluish green chalcedony, colored by chromium and nickel, is marketed under the trade name “Aquaprase.” Photo by Kevin Schumacher.

A new type of chalcedony (figure 1) was recently submitted to GIA’s Carlsbad laboratory by Yianni Melas of Greece. According to Melas, this material originated in Africa (figure 2), although a more precise location has not been made available. The translucent material displayed a vibrant bluish green color and is currently marketed under the trade name “Aquaprase.” Although chalcedony varieties such as chrysoprase and Gem Silica are well known and occur in yellowish green and greenish blue colors, the color of this material was distinctly different from any African chalcedony examined by GIA to date.

Figure 2. A large piece of chalcedony rough recovered from the mining area. Photo by Yianni Melas.
From a gemological perspective, it was important to conclusively determine that this material was naturally colored and not artificially dyed. Since the quartz crystals present in this material were colorless rather than brown, we ruled irradiation out as a possible treatment. Microscopic examination of rough and cut stones in conjunction with chemical analysis and visible spectroscopy were used to characterize this chalcedony. Standard gemological testing revealed an RI range from 1.531 to 1.539, with no observable birefringence. The SG, measured hydrostatically, ranged from 2.55 to 2.57. A handheld spectroscope revealed faint, narrow lines in the red end of the spectrum, rather than the broadband absorption one would expect if the material had been dyed with an organic pigment. All of these features were consistent with natural-color chalcedony.

Microscopic examination revealed a granular aggregate structure with a few areas showing subtle banding and faint green concentrations of color between some of the coarser quartz grains, which appeared to be a greenish mineral phase located along the grain boundaries. A waxy luster was observed on fractured areas, consistent with an aggregate material. Some areas contained small cavities that were filled with colorless drusy quartz crystals (figure 3, left and center). Dark brown and black inclusions of various metal oxides were also observed scattered throughout most of the samples examined, along with some areas of whitish cloudy inclusions that were not identified (figure 3, right).

Figure 3. The Aquaprase samples contained minute pockets of colorless drusy quartz (left and center) and irregular brown and black metal oxide inclusions (right). Photomicrographs by Nathan Renfro; field of view 2.83 mm (left), 4.76 mm (center), and 4.62 mm (right).
Raman analysis confirmed the material was quartz. EDXRF was used to analyze the trace-element metals that might be responsible for the bluish green color. All seven finished gemstones tested showed the presence of chromium and nickel. Interestingly, iron, vanadium, and copper were also detected in one of the cut samples, but these elements might not be related to the color, as other bluish green samples did not contain them. Visible spectroscopy (figure 4) revealed broad absorption bands centered at approximately 420 and 600 nm, with a large transmission window at approximately 500 nm producing the bluish green color. Sharp absorption peaks at 646, 676, and 679 nm were presumably related to chromium (http://www.gia.edu/gia-news-research-nr7809).

Figure 4. The visible spectrum for the Aquaprase (bluish green trace) showed two broad
absorption bands at 420 and 600 nm in addition to sharper peaks at 646, 676, and
679 nm. This absorption pattern is clearly different from that of chrysoprase (yellowish
green trace) and Gem Silica (greenish blue trace).
This new type of African chalcedony is easily recognized by its unique composition and absorption spectrum, which is significantly different from the chrysoprase and Gem Silica varieties. The attractive bluish green color of Aquaprase, which may be caused by chromium and nickel, should prove to be a popular and welcome addition to the gem trade. @chapter:3 @chapter:0 @chapter:3


# Publication Year: 2023
# Title: Purple Anhydrite
# Abstract: Figure 1. This 2.13 ct purple stone was identified as the rare collector gem anhydrite. Photo by Adrianna Gudino.
Recently, the Carlsbad laboratory received a 2.13 ct transparent purple octagonal step cut, measuring 7.32 × 6.34 × 6.01 mm (figure 1), for a colored stone identification service. Microscopic observation showed twinning planes, cleavage cracks, needle-like inclusions, fluid fingerprints, and strong doubling of many internal features, confirming the stone was doubly refractive (figure 2).

Figure 2. Twinning planes and fluid fingerprints were observed throughout the faceted purple anhydrite. Photomicrograph by Nathan Renfro; field of view 3.89 mm.
Standard gemological testing revealed a specific gravity of 2.97 and a refractive index of 1.570–1.615 with a birefringence of 0.045. The refractive index measurement also indicated the stone was biaxial positive, and a biaxial interference figure was resolved using a conoscope and polarized light. Purple and light purple pleochroism was observed using a dichroscope. The specimen had no fluorescence reaction when exposed to long- and short-wave UV light. These characteristics were consistent with the rare collector gem anhydrite.
Raman spectroscopy confirmed that the stone was anhydrite. Using polarized ultraviolet/visible/near-infrared spectroscopy, we were able to determine that the purple color resulted from a prominent absorption band centered at around 550 nm. A sharp absorption feature was also observed at 307 nm.
Anhydrite is a calcium sulfate with the chemical formula CaSO4. It is not well suited for use in jewelry due to its low hardness of 3.5 on the Mohs scale and its perfect cleavage in one direction. This orthorhombic mineral is commonly formed by the dehydration of gypsum, which has the chemical formula CaSO4•2H2O, and can have multiple colors ranging from colorless to pale blue, light pink, and brown that is colored by impurities. Occurrences of purple anhydrite have been reported in Switzerland, Iran, and Sri Lanka (see, respectively, Spring 1998 Gem News, p. 60; Fall 2000 Gem News, p. 262; Fall 1988 Gem News, p. 179).
Faceted gem-quality and single-crystal anhydrite is rare, and while the Carlsbad laboratory has examined a couple of anhydrite gems, they were mostly aggregates bluish in color. This is the first example of a transparent purple faceted single crystal anhydrite examined at GIA’s Carlsbad laboratory. @chapter:15 @chapter:0 @chapter:15


# Publication Year: -
# Title: Spring 2016 Auction Update: Big Checks – Mega Diamonds
# Abstract: Christie’s sold the 14.62 ct. Fancy Vivid blue Oppenheimer Blue diamond – the largest Fancy Vivid blue ever to come up for sale – for $57.5 million on May 18. Courtesy of Christie’s

	Big diamonds – really big ones– dominated the news in May. Christie’s sold the 14.62 carat (ct.) Oppenheimer Blue for the highest price ever paid for any gemstone at auction: $57.5 million. Also, mining company Lucara Diamond Corp. auctioned one of its major finds − a 812.77 ct. rough − for over $63 million and will sell its 1,109 ct. rough diamond named Lesedi La Rona at the end of next month.

	Lucara auctioned the 812.7 ct. diamond May 8 with the winning bid going to a Dubai-based firm, Nemesis International. It was a record price for a rough diamond and unlike most diamond tenders, which are outright sales, it was for a 90% share in the stone, with the remainder held by Lucara.

	The record price will certainly buoy expectations for Sotheby’s June 29 auction of Lucara’s 1,109 ct. stone – the second largest rough diamond ever found. That auction will be very public, conducted at Sotheby’s in London. Lucara had said it expected to sell for more than $70 million, a safe assumption after the smaller of the two fetched 90% of that price.

	As if the Lesedi La Rona’s 1,109 carats (originally reported at 1,111 cts.) were not large enough, the company announced that a 374 ct. rough found the day before had once been part of it. The company said it did not know if the piece broke off naturally or during the mining process.

This 1,109 carat rough Type IIa diamond, named Lesedi La Rona, was unearthed in Botswana last year – the second largest ever found − will be sold by Sotheby’s later this year. Courtesy of Lucara Diamond

	Both Lucara diamonds came from the Kerowe Mine in Botswana; Lucara, based in Vancouver, is a full owner. Lucara, which found these two large diamonds last fall, said Kerowe had yielded eight stones larger than 100 carats during the first quarter of this year. The mine produces about 100,000 carats yearly with an average price of $649 per carat, according to the company’s annual report.

	The Dubai dealer, Nemesis, purchased a 404 ct. rough mined in Angola by Lucapa Diamond Co. earlier this year for a reported $16 million. The diamond will be sold through De Grisogono, a Swiss-based luxury jeweler headed by Fawaz Gruosi.

	Another group of significant diamonds – smaller but more colorful – are set to post price records in the final round of spring auctions.

	Christie’s sold the GIA-graded 14.62 ct. Fancy Vivid blue Oppenheimer Blue diamond in Geneva on May 18 – the largest Fancy Vivid blue ever to come up for sale. Not to be outdone, Sotheby’s Geneva sold the 15.38 ct. GIA-graded Fancy Vivid pink Unique Pink diamond, the largest diamond of that grade ever to go under the hammer. The $31.6 million price came in at the lower end of the pre-sale estimate for the diamond mined in the old Kimberley deposits in South Africa. A 5.09 ct. GIA-graded Fancy Vivid green diamond will provide the finale for the 2016 spring season. The diamond, tracked from rough to rectangle cut and mounted in a ring surrounded by Fancy pink melee, is expected to sell for $16 to $20 million.

 This 5.03 ct. Fancy Vivid green diamond, named the Aurora Green, is the largest Fancy Vivid green graded by GIA as of this year. It will be auctioned May 31 at Christie’s Hong Kong where it is expected to sell for $16-$20 million. Photo courtesy of Christie’s

	ROUGH DIAMONDS

	De Beers’ chairman Philippe Mellier has noted that the company is “adopting a prudent mindset” for its rough diamond sales through the middle of the year. The company sold $660 million at its April sight (now called cycle) on top of about $1.2 billion at its two previous cycles in 2016. The company, however, announced its production for the year will be down about 10% – 26 to 28 million carats – for the year.

	De Beers remained profitable through a difficult 2015, earning $571 million (half of its 2014 profits, however), but its parent company Anglo American continues to struggle with high debts incurred by other projects that commenced when Chinese demand for resources seemed insatiable. Anglo is hoping to realize some $150 million from the sale of De Beer’s long-time Charterhouse Street headquarters.

	Alrosa, the world’s largest producer by volume, estimated its yearly production will be 37 to 39 million carats, equal, to or slightly lower than 2015 levels. The company withheld 22 millions carats from the market last year as demand collapsed in the second half. The company stated that it wants to sell down the stocks it accumulated last year, while also selling new production, but keeping prices stable. @chapter:49 @chapter:3 @chapter:49


# Publication Year: -
# Title: U.S. Retail Sales Remain Cautious
# Abstract: At Christie’s recent New York auction, an Asian buyer paid a record price of $5.1 million for a four-strand natural colored pearl necklace with pearls ranging from between 4.90 mm to 12.65 mm in size. Prices for other lots, however, were off from the peaks of 2013-2014.

                      The U.S. Census Bureau reports that specialty jewelry store sales fell 5.8% by value for the first two months of 2015 compared to 2014, while watch and jewelry sales from all channels were relatively flat.

The government figures reflect consumer caution throughout the retail sector, with electronics down 5% and durable goods sliding 2.4%.

Jewelry unit sales, however, were higher than the value numbers indicate due to declines in the price of gold and diamonds from early 2014 coupled with down-trading in diamond quality.

Consumer confidence, which rose several points in March, has improved along with the economy, but economists say wages have not risen in tandem and the decreased prices of gasoline and oil have not spurred retail sales in other areas.

De Beers’ Diamond Insight Report, issued last month, reported that growth of diamond jewelry sales in the U.S. was up 7% by value for 2104. This is more than double other estimates that pegged U.S. diamond jewelry sales from flat to up by 3%. The report also estimated Chinese growth at 6% and India rupee growth at 3% (down 1% when measured in U.S. dollars). The report cited a positive outlook for 2015, despite some headwinds.

The March 23-27 De Beers sight was especially large – $690 million − with as much as $100 million additional goods available from client refusals of boxes at the January and February sights. Clients refused 30-40% of the rough boxes on offer this month – the highest percentage since the economic crisis of 2009-2010 – because of price and inventory issues. De Beers held firm on prices across the board, even as rough prices exceed the cost of polished for many categories. Polished prices have declined by an average of 7% from last fall according to several price reports, while polished inventories continue to rise.

AUCTIONS: The first major jewelry auctions of 2015 continued the trend of subdued demand for ultra-luxury items noted at last month’s BaselWorld fair.

Only 67% of Sotheby’s April 6 Magnificent Jewels and Jadeite auction in Hong Kong sold (compared to 85% to 90% for such sales in the past three years), with private buyers taking all but two of the top 10 pieces. Without aggressive buying from dealers, prices seem to have receded from last year’s highs at this sale, but comparisons are often difficult because the unique properties some pieces have make them more desirable.

One price record was set at Christie’s April 14 New York auction: $5.1 million from a private Asian buyer for a four-strand natural pearl necklace with pearls that ranged between 4.90 mm to 12.65 mm in size. Other prices, however, were off from the peaks of 2013-2014, including a 25.49 carat (ct.) D potentially Flawless diamond by Graff that brought $134,000 per carat for a total of $3.4 million. This was about $50,000 to $60,000 per carat less than what similar goods achieved in previous sales. A 5.29 ct. Fancy Intense purplish pink diamond brought $1.1 million per carat, which was significantly off from similar stones auctioned during the past three years.

The Christie’s New York sale was 77% sold by value, again somewhat lower than recent years’ auctions.

At Sotheby’s New York April 21 auction a GIA-graded 100.20 ct. D IF Type II diamond was expected to sell for $19 to $25 million. Christie’s will offer a 5.18 ct. GIA-graded Fancy Vivid pink diamond at its May 13 Geneva sale. That lot is expected to sell for $9.5 to $12 million. @chapter:32 @chapter:3 @chapter:32


# Publication Year: 2023
# Title: Jewelry and Gemstone Market in Dubai Rebounds in 2022.
# Abstract: Opportunities for Thai Gems and Jewelry in the UAE
Thai gems and jewelry continue to enjoy consistent popularity and acceptance. Many jewelry companies in the UAE base their production in Thailand due to its reputation for skilled craftsmanship that rivals any other nation in the world.
In 2022 (January-October), Thai gems and jewelry were the highest exported products to the United Arab Emirates, ranking third with a total value of 8.224.25 billion baht, marking a 73.11% increase from the same period in 2021. Among these exports, Thai jewelry made of gold was the highest valued at 4.364 billion baht, followed by diamonds at 2.250 billion baht. Unworked gold valued at 901 million baht and gemstones valued at 589 million baht followed suit. @chapter:32 @chapter:3 @chapter:32


# Publication Year: 2023
# Title: Star Aquamarine
# Abstract: Figure 1. A 13.37 ct grayish blue aquamarine displaying asterism. Photo by Towfiq Ahmed.
The Carlsbad laboratory recently received a grayish blue aquamarine for an identification report. The unique 13.37 ct oval double cabochon displayed a six-rayed star (figure 1). Standard gemological testing revealed a spot refractive index of 1.570 and a hydrostatic specific gravity of 2.68. Raman analysis confirmed that the stone was beryl.

Figure 2. Negative crystals, film-like inclusions, and ilmenite were observed under magnification in the star aquamarine. Photomicrograph by Jessa Rizzo; field of view 3.57 mm.
Under magnification (figure 2), the stone displayed planes of negative crystals, film-like inclusions, ilmenite, and reflective particles that resulted in a six-rayed star. Asterism in aquamarine is due to three sets of elongated channel-like or thin-film inclusions oriented in three different directions perpendicular to the c-axis (e.g., Spring 2004 Gem News International, p. 104; K. Schmetzer et al., “Asterism in beryl, aquamarine, and emerald—an update,” Journal of Gemmology, Vol. 29, No. 2, 2004, pp. 66–71). Of all the aquamarines examined at GIA laboratories, this was one of the first to display asterism. @chapter:19 @chapter:0 @chapter:19


# Publication Year: 2024
# Title: Large CVD-Grown Diamond Resubmitted after HPHT Treatment
# Abstract: Figure 1. This 15.73 ct G-color CVD-grown diamond showed indications of HPHT treatment. Photo by Jian Xin (Jae) Liao.
In January 2022, the record holder for largest diamond grown by chemical vapor deposition (CVD) was a 16.41 ct square modified brilliant with G color and VVS2 clarity that showed no indications of post-growth treatment (Spring 2022 Lab Notes, pp. 54–56). Recently, this diamond was resubmitted to the Carlsbad laboratory with a weight of 15.73 ct (figure 1). Standard data collection indicated that since the original submission, the stone had undergone high-pressure, high-temperature (HPHT) treatment. Consequently, this provided a case study showing the spectral and fluorescence differences between the as-grown and HPHT-treated versions. The color and clarity grades remained unchanged.
Although HPHT processing of CVD-grown diamonds is often performed to improve the color grade by reducing brown coloration (S. Eaton-Magaña and J.E. Shigley, “Observations on CVD-grown synthetic diamonds: A review,” Fall 2016 G&G, pp. 222–245), the diamond displayed no observable color improvement. It is also likely that the HPHT treatment created frosting of the facets that required repolishing, which could partially account for the 0.68 ct weight loss.

Figure 2. DiamondView fluorescence images collected on the originally submitted CVD-grown diamond (left, from Spring 2022 Lab Notes) exhibited no evidence of post-growth treatment, while the recent submission (right) showed signs of HPHT treatment. Images by Stephanie Persaud (left) and GIA staff (right).

Figure 3. PL spectra collected on the CVD-grown diamond in January 2022 and recently with 514 nm (left) and 457 nm (right) excitation. Diamond Raman lines are scaled as equal, and spectra are offset vertically for clarity.
DiamondView fluorescence imaging showed pronounced differences between the as-grown and treated stages (figure 2). This color change in fluorescence imaging is often seen in HPHT-treated CVD-grown diamonds due to the reduction of nitrogen vacancy (NV) centers (NV0 with zero-phonon line [ZPL] at 575 nm and NV– at 637 nm) and an increase in H3 (NVN0; ZPL at 503.2 nm). The changes in the defect concentrations leading to the differences in the fluorescence colors were also evident in photoluminescence (PL) spectroscopy collected at liquid nitrogen temperature. Figure 3 shows the PL results with 514 and 457 nm excitation for the 16.41 and 15.73 ct stages of the diamond.
With HPHT treatment, there was a decrease in the NV centers and an increase in the silicon vacancy (SiV–) center at 737 nm in the 514 nm PL spectrum. In the 457 nm PL spectrum, the 468 nm peak and 3H peak (ZPL at 503.5 nm) were no longer detected, while features developed at 494.1, 500.4, and 506.2 nm along with the H3 peak at 503.2 nm.

Figure 4. Comparison of the cathodoluminescence images from before HPHT treatment (left, from Spring 2022 Lab Notes) and afterward (right) showed no observable differences. Images by Elina Myagkaya.
As expected with a treated CVD-grown diamond, there were no major changes in many of the growth features. The cathodoluminescence images in figure 4 show no observable differences; the black dots are associated with lattice dislocations. The seven growth interfaces seen in figures 2 and 4 appear unmodified.
This stone allowed for an interesting comparison of a CVD-grown diamond before and after commercial HPHT treatment. @chapter:9 @chapter:1 @chapter:9


# Publication Year: -
# Title: Spring 2010 G&G Book Reviews
# Abstract: “Modern Jewellery Design: Past and Present”
By Reinhold Ludwig, 399 pp., hard-cover, illus., publ. by Arnoldsche Art Publishers [www.arnoldsche.com], Stuttgart, Germany, 2008. US$85.00

“Genuine Diamonds Found in Arkansas, 3rd Ed.”
By Glenn W. Worthington, 182 pp. with DVD supplement, illus., publ. by Mid-America Prospecting [www.diamondsinar.com], Murfreesboro, AR, 2009. US$35.00

“Cartier: Innovation Through the 20th Century”
By François Chaille, 271 pp., illus., publ. by Flammarion [www.editions.flammarion.com], Hoboken, NJ, 2007. US$65.00

“The Most Fabulous Jewels in the World: Graff”
By Meredith Etherington-Smith, 196 pp., illus., publ. by Cultureshock Media [www. cultureshockmedia.co.uk], London, 2007. £75.00

“Ruby, Sapphire, and Emerald Buying Guide, 3rd Ed.”
By Renee Newman, 187 pp., illus., publ. by International Jewelry Publications [www.reneenewman.com], Los Angeles, 2009, US$19.95

“Tables of Gemstone Identification”
By Birgit Günther, 256 pp., illus., publ. by Verlagsbuchhandlung Birgit Günther, Idar-Oberstein, Germany, 2009, €87.50

“Archaeomineralogy, 2nd Ed.”
By George (Rip) Rapp, 348 pp., illus., publ. by Springer-Verlag [www.springer.com], Berlin, 2009, €139.05

“Imperishable Beauty: Art Nouveau Jewelry”
By Yvonne Markowitz and Elyse Z. Karlin, 168 pp., illus., publ. by MFA Publications [www.mfapublications.org], Boston, MA, 2008, $45.00

To view the full section, download the PDF above. @chapter:28 @chapter:2 @chapter:28


# Publication Year: 2015
# Title: Color-Change Garnets from Tanzania
# Abstract: Figure 1. This 7.61 ct “pastel pyrope” shows a strong pink color in warm incandescent light and a strong purple in cool LED light. Photos by Duncan Pay/GIA; courtesy of Jason Doubrava Gems & Minerals.

At the Riverpark Inn (Pueblo) show, Todd Wacks (Tucson Todd’s Gems,Tucson and Vista, California) and Jason Doubrava (Jason Doubrava Gems & Minerals, Poway, California) showed us interesting color-change or color-shift garnets from Tanzania (figure 1). According to them, these gems were mined in Morogoro, Tanzania, back in 1988, and documented the same year (see C.M. Stockton, “Pastel pyropes,” Summer 1988 G&G, pp. 104–106). The material resembled rhodolite rough and contained fine needle-like inclusions—most likely rutile.

	 Todd’s Gems

Todd Wacks outlines how garnets believed to be “regular” Tanzanian rhodolite when discovered in the late 1980s turned out to be rare color-change pyropes instead. In this video, he demonstrates their strikingly intense pink-to-purple color change under different light sources.
The gems were pinkish purple in daylight and showed a color change from intense pink in warm incandescent light to purple—almost like a fine amethyst—in cool LED light. Wacks said the larger stones display the most pronounced color change. Very similar color change phenomena have been reported for other purple “pastel pyropes” from Tanzania, Sri Lanka, and Madagascar.

The rough had been stuck in a safe deposit box for years, he said, because most potential buyers assumed it was rhodolite, saw the inclusions, and lost interest. A consortium including Doubrava, Wacks, and well-known gem artist Meg Berry recently acquired the 2–4 kg of rough, cut a few pieces, and discovered the color change. Wacks has been promoting the gem since then.

The group sent samples to Dr. George Rossman (California Institute of Technology, Pasadena), San Diego gemologist Kirk Feral, and GIA. According to Wacks, the gems are approximately 80% pyrope, 10% spessartine, and 10% almandine, with an RI of 1.736. (This material will be the subject of a more detailed paper in the Winter 2015 G&G.)

	vdAaco

Jewelry designer Mary van der Aa presents her jewelry designs, which feature a variety of gems including “hot pink” tourmalines from well-known mines in San Diego County and color-change pyrope garnets from Tanzania.
Sharing booth space with Wacks was colleague and jewelry designer Mary van der Aa (vdAaco, Vista, California). She produces jewelry designs for many of the gems he cuts, including pastel pyropes and pink tourmalines from some of the mines in San Diego County (figure 2). Her jewelry also features stones cut by renowned gem artist Meg Berry.

Figure 2. This hand-fabricated 14K rose gold and yellow gold pendant by Mary van der Aa features a 6 ct “hot pink” tourmaline from the Stewart mine, cut by Todd Wacks. Photo by Duncan Pay/GIA; courtesy of vdAaco. @chapter:14 @chapter:0 @chapter:14


# Publication Year: -
# Title: Online Diamond Sales 17% of U.S. Market; New Auction Records
# Abstract: The “Imperial Kashmir,” a 17.16 ct sapphire, achieved a world record for a sapphire when it sold for $236,404 per carat ($4.01 million) at a Sotheby’s Oct. 7 auction in Hong Kong. All photos courtesy Sotheby’s

                      A recent De Beers study reported that worldwide retail sales of diamond jewelry totaled $79 billion last year; up $5 billion on a 7% increase in U.S. demand and 12% increase in China.

Online sales of diamond jewelry comprise about 17% of the market in the U.S., according to the study. These sales include both strictly online companies such as Blue Nile, as well as traditional retailers who also sell over the Internet.

The De Beers report also noted that 25% of Chinese consumers now research prospective diamond purchases online before making an actual purchase and that the number of retail stores selling diamond jewelry increased 30% from 2010 to 2013. There are, however, strong signs that the heady growth continues to slow, according to De Beers. Retailers in Guangdong Province reported that sales declined 5.1% for the first eight months of the year, while sales of gold pieces nationwide fell 9.1% during that period, according to a government report.

In the U.S., the Department of Commerce reported that jewelry and watch sales from all sales channels increased 4.9% in August, compared to the same month in 2013. This rise reflects even greater sales volume because prices for gold and diamonds declined several percentage points in this year.

De Beers’ noted that diamond production increased 7% to 145 million carats, still well under the 2005 peak of 175 million carats. It also predicts that production will decline, despite new sources coming on stream, because older mine deposits are getting more costly to work as operations go deeper and ore-grade declines.

De Beers’ Oct. 6 – 10 sightis estimated at $465 million, much smaller than previous sights. The October sight is usually small because it comes just before Diwali, which begins Oct. 20.

Indian diamond manufacturers typically take a two-to-three week break in operations and diamond firms settle their accounts for the year during Diwali. This year, some companies have reportedly offered discounts up to 10% on some slower-moving polished goods to enable them to settle with banks that are cutting back on credit or, in the case of the Antwerp Diamond Bank (ADB), closing doors and calling in loans. The Gem and Jewellery Export Promotion Council, India’s largest industry organization, has denied reports of heavy discounting, saying the long-term prospects for the country’s diamond trade “remain robust.”

ADB has a loan portfolio of $1.6 billion – with nearly all of those clients located in Antwerp. However, 60% of that portfolio is held by Indian firms with roots in Mumbai and Surat. Clients reportedly have one year to close their debts to the bank.

Immediately after the ABD news hit, the Indian Branch of Standard Chartered Bank reportedly informed clients that is was further reducing its financial exposure to the diamond industry and insisting on increased collateral to secure credit lines.

Rough prices have been softening in recent months because of the tightening credit and price resistance in the polished market. De Beers lowered prices very slightly on some high quality goods at the past sight, but prices from other producers sold at tender sales have reportedly fallen by 7%.

AUCTIONS: The records for prices keep breaking as the world’s ultra-wealthy buyers vie for rare, important gemstones. At Sotheby’s Oct. 7 Hong Kong auction, an 8.41 ct GIA-graded Fancy Vivid purple-pink, Internally Flawless diamond drew a winning bid of $17,768,041 from a private buyer from Asia. It was the highest price ever paid for a Vivid pink diamond at auction and, at $2.1 million per carat, it came close to besting the all-time per-carat price achieved by a gemstone.

	A GIA-graded pear shaped Fancy Vivid purple-pink diamond weighing 8.41 cts sold for more than $17.7 million at the Sotheby’s Oct. 7 auction.
The record pre-carat price for a Kashmir sapphire was broken twice at the same sale, the second time within minutes of the first.

The first lot was a 12.0 ct step cut mounted by Cartier, which drew a final price of $2.32 million or $193,975 per carat, besting the record set last year by just over $13,000. A few lots later, however, an Asian collector paid $4.01 million for the 17.16 ct “Imperial Kashmir.” At $236,404 per carat, it easily topped the price mark that had just been set.

While the Intense purple-pink set a record for a diamond of that grade, a pink diamond, graded Fancy Intense by GIA that weighed 24.78 cts, holds the record price for any gemstone, selling for $46 million in 2010.

	This 12.0 ct step cut sapphire and platinum ring by Cartier set with emeralds and diamonds sold for $2.32 million at the Oct. 7 Sotheby’s auction. It briefly set a record at $193,975 per carat until it was surpassed by the “Imperial Kashmir.” @chapter:37 @chapter:3 @chapter:37


# Publication Year: -
# Title: Emerald Dealer Shares Risks and Rewards
# Abstract: Arthur GroomArthur Groom & Company

Interview with Arthur Groom, Arthur Groom & Company
International gem dealer Arthur Groom says that even when you’re learning about gemology, you’re thinking business. In this exclusive interview with GIA conducted at the 2013 Tucson Gem Show, Groom delivers a highly instructive tutorial on the critical nexus between gemology and business.

In the course of the interview, Groom holds up two different emeralds and talks with great detail and clarity about the aesthetic as well as economic decisions that must be made about cutting the rough. He demonstrates the ramifications of those decisions both in the ultimate beauty of the stone and its value. One side of a piece of rough he shows off, he says, will go for $300 a carat; the other side for $1000. The sawing is everything, Groom proclaims.

His focus in the interview is on emeralds, for which he expresses enormous affection. This affection is undiminished by the acknowledged difficulty emeralds present to dealers. Groom says that because they are the most complex of colored stones, bidding on them is equally complex. But he offers some of the expertise that has enabled him to show off beauties like two featured in this video, valued at $15,000 to $18,000 per carat.

Groom also discusses the Afghan market at length, having recently traveled there. He surmises that if peace and mechanization ever come to Afghanistan, it will finally realize its potential as the world’s richest color stone source. As it is, he reports, the material coming out under the crude current conditions is pretty outstanding. It has a higher than average yield of 33% crystal clear, deeply colored rough. For Groom, the risk for the colored stone dealer is in the rough, and all other factors being equal, Afghanistan is well worth the risk. @chapter:38 @chapter:3 @chapter:38


# Publication Year: 1992
# Title: Diamond Sources and Production: Past, Present, and Future
# Abstract: Africa was the major source of diamonds for most of the 20th century, but Australia and Sakha (of the Russian Federation) now produce about half the world’s supply. Also, most of the production today comes from primary sources (kimberlites and lamproite), whereas secondary (alluvial) sources dominated as recently as the early 1970s. Although the annual production of rough more than doubled in the 1980s, the production of rough yielding good-quality polished gems has not increased appreciably. The economic potential of a kimberlite or lamproite occurrence depends on the tonnage and grade of the ore, as well as on the quality of the diamonds it contains. The authors predict that the early 21st century will see the Russian Federation as an even more important source of diamonds and Canada as a major producer. @chapter:50 @chapter:3 @chapter:50


# Publication Year: -
# Title: Fall 2009 G&G Lab Notes
# Abstract: Fancy Red Irradiated and Annealed Diamond
Diamond With Hydrogen Cloud and Etch Channels
Large Type Ib Yellow Diamond Colored by Isolated Nitrogen
Patterned Green Radiation Stains in Diamond
Pumpellyite in Quartz
A Useful Technique to Identify Negative Crystals in Ruby
“Textbook” Columbite in Topaz

To view the full section, download the PDF above. @chapter:29 @chapter:1 @chapter:29


# Publication Year: 2015
# Title: Coral Inclusions in Plastic
# Abstract: Figure 1. This 37.50 ct plastic bead contained visible fragments of carbonate-type coral (the lighter spots). Photo by Gagan Choudhary.

Composites assembled from opaque-to-translucent and transparent gem materials such as turquoise, chalcedony, opal, chrysocolla, tourmaline, and peridot have become popular over the past few years, as evidenced by the number of samples received for identification at the Gem Testing Laboratory in Jaipur, India. Recently, we examined an orangy red bead of plastic (figure 1) with embedded fragments of coral.

The round bead weighed 37.50 ct and measured 20.62 × 20.57 × 14.02 mm. The bead was represented as coral, but its smooth texture along with the luster was sufficient enough to rule out that possibility. A few spots of lighter color (again, see figure 1), visible to the unaided eye, made it more interesting. Under strong fiber-optic light, minute transparency was observed, while microscopic examination revealed numerous gas bubbles scattered throughout the bead. Sharp boundaries between the lighter spots and the host bead suggested that these spots of lighter color were actually fragments of some other material. These randomly oriented fragments also displayed some concentric radiating structures (figure 2, left), typically seen in carbonate-type corals. Some chips also showed elongated sections (figure 2, right), along with some whitish to faintly colored areas.

Figure 2. Some of the fragments embedded in the plastic bead displayed concentric radiating structures (left), typically seen in carbonate-type coral, while others show elongated sections (right). Also note the sharp edges and whitish to faintly colored areas of the fragments. Photomicrographs by Gagan Choudhary; field of view 5.08 mm.
Although the bead was obviously an artificial product, its major component was still to be identified. A spot refractive index of approximately 1.53 and hydrostatic specific gravity of 1.97 were obtained. Under UV light, the bead fluoresced orange, with a stronger reaction to short wave than long wave; a desk-model spectroscope revealed a broad absorption band from the violet to yellow-orange region. Raman spectroscopy (figure 3) confirmed the major component of the bead as plastic, while the grains were identified as carbonate. We did not detect any carotenoid-related peaks, which have been suggested as the cause of color in pink-to red-coral (C.P. Smith et al., “Pink-to-red coral: A guide to determining origin of color,” Spring 2007 G&G, pp. 4–15). On the basis of Raman spectra and concentric radiating structure, the sharp fragments were identified as white coral.

Figure 3. Raman spectra using 785 nm laser confirm that the major component of the
bead is plastic (blue trace), while the grains are a carbonate such as calcite (red trace).
The lack of carotenoid-related peaks suggests the use of white coral fragments.
Coral-plastic composites have been reported previously (e.g., Fall 2008 Lab Notes, p. 253). Further, orange-red plastics have also been known as coral imitations for decades. This specimen turned out to be notable because of the use of coral fragments as inclusions; however, we could not clearly understand its purpose. @chapter:54 @chapter:4 @chapter:54


# Publication Year: 2022
# Title: Skull Carved of Meteorite
# Abstract: A skull carved from the Gibeon meteorite, which landed in Namibia in prehistoric times. The brown line is a tridymite inclusion. Exhibited by Nature’s Geometry at the 2022 AGTA show in Tucson. Photo by Robert Weldon; courtesy of Lee Downey.
At the AGTA show, Nature’s Geometry (Tucson) had on display a life-sized skull carved of meteorite (see above). The skull, “Gaia,” was a collaboration between Lee Downey of Artifactual Studios (Tucson and Bali, Indonesia) and Balinese artist Ida Bagus Alit. It was carved from two pieces of the Gibeon iron meteorite, which landed in prehistoric times after bursting into pieces upon coming through the atmosphere. Its fragments are scattered over a large area in Namibia. Based on radiometric dating, the meteorite is estimated to be around four billion years old. Long before Westerners documented it in the early 1800s, the Nama people used pieces of it as weapons and tools.
Downey and Alit worked on the carving from March 2015 to January 2020 in the workshop Downey shares with Ratu Pedanda Manuaba, a high priest of Bali. In Balinese culture, meteorites are seen as powerful, and meteorite iron is used to make traditional keris (daggers) for ceremonial use.
The Gibeon meteorite’s makeup is about 90% iron and 8% nickel, with small amounts of cobalt and phosphorus. Downey said the material is somewhat soft and sticky. The critical aspects were maintaining the proportions and watching for potential imperfections in the material. “Cracks and pockets of odd space junk can pop up,” he said. “Luckily Gaia was basically flawless. She was difficult but forgiving.”
The work was done using hacksaws, steel grinders, and rotary carving setups. Protective gear was required when using cutting burrs because the tiny shards coming off the skull were “like little razor blades flying around.” Based on models of the human skull, a sphere-shaped piece of the meteorite was carved for the upper cranium and a block for the jaw, which is articulated and removable. Roughly 159 lbs. (72 kg) of material were cut and ground away to form the 39 lb. (18 kg) skull. After carving, the skull was fully polished to a chrome-like finish.
The final step was etching with a weak acid to reveal the meteorite’s fine octahedrite structure, visible in the pattern on the skull’s surface. The pattern, known as a Widmanstätten pattern or Thomson structure, is composed of interwoven bands of kamacite and taenite (iron-nickel alloys) and develops over millions of years of very slow cooling. It is revealed only through cutting, polishing, and etching.
The brown line on top of the skull is an inclusion of tridymite, a silica polymorph. Tridymite is also found on Earth, the moon, and Mars, and in planet-forming disks of dust and gas around stars.
Downey has previously described the human skull as “undeniably sure to register emotions in all of us. It has all the fear of death, the reminder of being alive, and the possibility of something greater in store…out there in the mysterious beyond.”
“The intense gravity of this extraterrestrial metal is itself a mystery of life,” he said. “Four billion years old and counting, the long travel to arrive on Earth, the rare beauty of the crystal patterns that can only form in the vacuum of space. The symmetry of the entire tale is beyond human comprehension.” @chapter:40 @chapter:0 @chapter:40


# Publication Year: 2023
# Title: Spotted Diamond
# Abstract: Numerous metal sulfide crystals scattered throughout a 3.05 ct Fancy Light gray diamond. Photomicrograph by Michaela Damba; field of view 14.52 mm.
The author recently examined a large 3.05 ct Fancy Light gray diamond featuring dark crystals scattered throughout (see above). It had a clarity of I3, the lowest grade for gem-quality diamond, but demonstrated that low-clarity diamonds can sometimes be more intriguing than their higher-clarity cousins. Stones with numerous eye-visible crystal inclusions such as this are sometimes referred to in the trade as “salt and pepper” diamonds.
Numerous attempts to identify the dark crystals using Raman spectroscopy proved unsuccessful. X-ray fluorescence revealed high levels of iron, leading the author to conclude that they were likely metal sulfides rather than graphite. This presumption has not been confirmed with Raman spectroscopy. @chapter:39 @chapter:1 @chapter:39


# Publication Year: 2015
# Title: Irradiated Green-Blue CVD Synthetic Diamonds
# Abstract: Figure 1. These intensely colored CVD synthetic diamonds, weighing 0.64 ct (left) and 0.43 ct (right), are color graded as Fancy Deep green-blue and Fancy Deep greenish blue, respectively. Photo by Sood Oil (Judy) Chia.

As-grown CVD synthetic diamonds are routinely treated in order to create attractive colors. Irradiated CVD synthetic diamonds without a multi-step treatment process are rarely seen in the lab, though an irradiated Fancy Deep gray-blue CVD synthetic has been reported (Fall 2014 Lab Notes, pp. 240–241). The New York lab recently examined two such examples: a 0.64 ct Fancy Deep green-blue and a 0.43 ct Fancy Deep greenish blue specimen (figure 1).

Figure 2. DiamondView images reveal linear striations in the pavilions of the 0.64 ct (left) and 0.43 ct (middle) specimens. A face-up image of the 0.43 ct synthetic shows a yellowish green zone of growth interruption (right). Images by Kyaw Soe Moe.
Dark inclusions, faint color bands, and chips on the girdle were observed in both specimens under the microscope. Tatami-like strain was also seen in both diamonds under cross-polarized light. DiamondView images revealed parallel green linear striations in the pavilions (figure 2). Face-up DiamondView images also showed yellowish green zones, which were formed by growth interruptions (again, see figure 2). Both stones were pure type IIa diamonds with no other defects in the IR spectra. High-resolution UV-Vis-NIR absorption spectra detected Si-V center defects at the 736.5–736.9 doublet (737 nm center, (V-Si-V)–); the spectra also revealed radiation-related peaks at 393.5, 464.3, 469.9, 594.2, 666.5, 735.8, and 741.2 nm (figure 3). The 393.5 band is from the ND1 center, a negatively charged vacancy (V–). An intrinsic radiation center (TR12) was detected at 469.9 nm. The TR13 center at the 464.3 peak is a local vibrational mode associated with the TR12 center, and the 594.2 band (595 nm center) is a typical radiation-induced center. The 666.5 peak is attributed to a neutral self-interstitial (I0) defect. The 735.8 band, also caused by the I0 defect, is related to the 666.5 band. Strong absorption from the GR1 center, which contains neutral vacancies (V0), was detected at 741.2 nm. All these radiation-related peaks can be destroyed by HPHT treatment, while peaks at 666.5 and 735.8 nm can be annealed out at temperatures ranging from 420º to 540ºC (see A.T. Collins, “Spectroscopy of defects and transition metals in diamond,” Diamond and Related Materials, Vol. 9, Nos. 3–6, 2000, pp. 417–423). The presence of these peaks indicates that these CVD synthetics were either annealed at lower temperatures (420º to 540ºC) or irradiated without annealing.

Figure 3. Absorption spectra of the two green-blue CVD synthetics at liquid nitrogen
temperature revealed radiation-related peaks. The peaks at 666.5 and 735.8 (both neutral
self-interstitial defects) indicate that these samples were annealed at lower temperatures
or irradiated without annealing. The Si-V center defect (737.0 nm center) can also be
observed at the 736.5–736.9 nm doublet. Many unknown absorption bands (unlabeled
in this spectra) are also detected.
Although microscopic features such as strain pattern can be helpful in the identification of CVD synthetics, they are not conclusive. DiamondView imaging is very useful for this purpose due to its ability to detect linear striations. As CVD growth techniques continue to improve, we anticipate that intensely colored, high-quality CVD synthetic diamonds will become more prevalent in the trade. @chapter:9 @chapter:1 @chapter:9


# Publication Year: 2019
# Title: Glass Bangles
# Abstract: Figure 1. The 343.94 ct translucent white bangle on the left and the 355.52 ct translucent mottled purplish gray and green bangle on the right were carved from manmade glass. Photos by Robison McMurtry.
Recently, the Carlsbad laboratory was sent two bangles for identification: a 343.94 ct translucent white bangle and a 355.52 ct translucent mottled light purplish gray and green bangle (figure 1). The white bangle could have easily been given a sight identification of nephrite due to its color and dullness. But its refractive index (RI) of about 1.500 eliminated the possibility of nephrite, which has an RI of 1.62. Further observation showed an even color and no natural inclusions. Gas bubbles of various sizes could be seen just below the surface (figure 2). The RI in combination with the gas bubbles indicated that this bangle was a manufactured product.

Figure 2. An elongated gas bubble seen below the surface of the white bangle. Photomicrograph by Nicole Ahline; field of view 3.57 mm.

Figure 3. Gas bubbles of various sizes could easily be seen throughout the mottled purplish gray and green bangle. Photomicrograph by Nicole Ahline; field of view 3.57 mm.
The mottled bangle had a color very similar to that of jadeite. An RI of 1.610, rather than the typical jadeite RI of 1.66, indicated that this piece was also not what it appeared to be. Gas bubbles were identified throughout the bangle (figure 3), further confirming that this was a manufactured product. Strings of gas bubbles were observed without magnification, an arrangement that could have easily been mistaken for a natural jadeite structure (figure 4).

Figure 4. Clusters of gas bubbles with a string-like structure in the mottled purplish gray and green bangle. Photomicrograph by Nicole Ahline; field of view 3.57 mm.
These gemological properties and observations identified these bangles as manmade glass and not the nephrite and jadeite they resembled. With nephrite and jadeite having such a rich cultural history, it is common for imitations to show up on the market. Items like these demonstrate the need to always be cautious when purchasing jewelry. @chapter:26 @chapter:0 @chapter:26


# Publication Year: 2014
# Title: Coated Fire Opal in the Chinese Market
# Abstract: Fire opal is an attractive variety of gem opal characterized by its red-orange-yellow bodycolor, with or without play-of-color. Since about 2013, the Chinese market has seen an increase in natural, synthetic (sold as Mexifire), and treated fire opals, posing identification challenges for the gemologist.

Figure 1. This 3.87 ct translucent orange fire opal with play-of-color was identified as a coated stone. Photo by Wen Han.
At the July 2014 Beijing Jewelry Fair, a fire opal with a rather unusual orange bodycolor (figure 1) attracted our interest. It was a 3.87 ct oval cabochon with fair play-of-color, measuring approximately 14 × 10 × 6 mm. Its spot RI of about 1.39 and hydrostatic SG of 1.85 were both lower than the values for most natural fire opal. It was inert to both long- and short-wave UV radiation; untreated fire opal may also be inert to UV radiation or show green and blue fluorescence. Magnification revealed obvious scratching and small pits on the surface (figure 2), suggesting a lower hardness and the presence of a coating. We cut the sample in half for further examination. High magnification clearly showed the boundary between the orange layer and the substrate, which was also orange opal. The coated layer was about 60–90 μm thick (figure 3).

Figure 2. Surface scratches and small pits were visible on the coated fire opal. Photo by Wen Han.

Figure 3. A cross-section image of the fire opal shows a coated surface layer about 60–90 μm thick. Photo by Wen Han; magnified 100×.
EDXRF chemical analysis detected mainly Si and minor amounts of Ca, Na, and K. Fourier-transform infrared (FTIR) and Raman spectroscopy were used to identify the coating. Infrared reflectance spectroscopy revealed three strong bands at 1099, 789, and 474 cm–1 that are related to the fundamental Si-O vibrations, as expected for natural fire opal. Then we scraped off the coating with a razor blade to obtain its infrared transmittance spectrum. The peaks, specifically those at 2926, 1729, 1451, and 1159 cm–1, indicated the presence of organic matter consistent with acrylic polymer (figure 4). The Raman scattering spectra of the fire opal revealed several peaks attributed to both the substrate opal and the coating (figure 5). The Raman bands at about 350, 785, and 1080 cm–1, due to different stretching and bending vibration modes of the Si-O system, are typical for opal-CT. Other peaks, including 1320 and 1610 cm–1, are attributed to the acrylic coating material. Acrylic coatings are applied to various gem materials, such as lapis lazuli and jadeite (Summer 1992 Gem News, p. 135). This coating of acrylic polymer was used to enhance the fire opal’s color and seal its fissures. The coating also lowered the stone’s RI and SG values.

Figure 4. The FTIR spectrum of the coating scraped from the surface of the fire opal exhibits characteristic peaks at 2926, 1729, 1451, and 1159 cm–1 consistent with acrylic polymer.

Figure 5. Raman bands at approximately 350, 785, and 1080 cm−1 are typical for opal-CT; the other peaks, including those at 1320 and 1610 cm–1, are attributed to the acrylic coating.
Our investigation, believed to be the first report of coated fire opal in the Chinese market, reinforces the need for caution when buying these products. This coated fire opal’s lower RI and SG values, combined with magnification and Raman spectroscopy, are effective and nondestructive means of identification. @chapter:48 @chapter:0 @chapter:48


# Publication Year: 2000
# Title: GE POL Diamonds: Before and After
# Abstract: This study of type IIa GE POL diamonds before and after HPHT annealing by GE significantly expands on their characterization. The color change was dramatic: from the N–O range through Fancy Light brown before, to D–H after. However, there was little change to the inclusions, graining, and strain as a result of HPHT exposure. Photoluminescence (PL) studies—conducted at liquid helium, liquid nitrogen, and room temperatures in the 245-700 nm range—identified a significant reconfiguration of the lattice involving substitutional impurities, vacancies, and interstitials. Key regions of PL activity included the areas of the N3, H3, and N-V centers. X-ray topography identified the extent of lattice distortion. Cathodoluminescence may help establish that a diamond is not HPHT annealed. A distinction between non-enhanced and color-enhanced type IIa diamonds can be made through a combination of observations and features. @chapter:22 @chapter:1 @chapter:22


# Publication Year: 2023
# Title: Quarterly Crystal: Geocronite in Fluorite
# Abstract: Figure 1. This 29.60 × 23.84 × 18.35 mm cluster of well-formed isometric fluorite and monoclinic geocronite crystals was recently discovered at the Milpo mine in Peru. Photo by Annie Haynes.
A tight crystal cluster of bright apple-green fluorite and opaque silvery gray geocronite, Pb14(Sb,As)6S23, was recently examined for this edition of Quarterly Crystal. The specimen shown in figure 1 measured 29.60 × 23.84 × 18.35 mm, and the fluorite portion played host to several small, well-formed monoclinic crystals, all situated near the surface. The crystals appeared to be geocronite, a very rare sulfide containing lead, antimony, and arsenic.

Figure 2. A combination of optical microscopy and Raman analysis identified the opaque silvery gray monoclinic inclusions as the very rare sulfide geocronite. Photomicrograph by Nathan Renfro; field of view 2.39 mm.
The specimen was obtained from Luciana Barbosa of Barbosa Minerals (Asheville, North Carolina). It came from a recent discovery at the Milpo mine in the Atacocha mining district of Pasco Province, Peru. The Milpo mine is known to produce fluorite crystals with inclusions of various sulfides. Since the fluorite and geocronite are intimately intergrown, the opaque silvery gray bodycolor of the inclusions in the fluorite, together with their monoclinic appearance shown in figure 2, strongly suggested geocronite.
The next logical step was laser Raman microspectrometry. Using this technique, we conclusively identified the inclusions as geocronite, thereby confirming our suspicions. It should be noted that, to the authors’ knowledge, this is the first time geocronite has been identified as an inclusion in any mineral. @chapter:15 @chapter:0 @chapter:15


# Publication Year: 2023
# Title: Star Beryl
# Abstract: Figure 1. Left: Black beryl beads displaying six-rayed stars. Right: Black beryl beads displaying twelve-rayed stars. Photos by Tinh Xuan Nguyen.
Asterism is not a common phenomenon in beryl species, but it has previously been reported in emerald and aquamarine (K. Schmetzer et al., “Asterism in beryl, aquamarine and emerald – an update,” Journal of Gemmology, Vol. 29, No. 2, 2004, pp. 65–71; Fall 2015 Gem News International, pp. 334–335). Recently, the author observed several star black beryl bead bracelets purchased from a Chinese e-commerce platform. For this report, four beads with noticeable asterism were collected for testing. The material was called “Devil Blue” aquamarine. The beads ranged from 9.11 to 9.47 mm in diameter and displayed a star phenomenon.
Of the four beads, two had six-rayed stars with arms intersecting at 60° angles (figure 1, left) and two had twelve-rayed stars with two sets of six-rayed stars located in the same concentric point but with different orientations—the two stars were offset by approximately 10° (figure 1, right). Gemological testing of the beads provided the following characteristics: a hydrostatic specific gravity varying from 2.67 to 2.73, a spot refractive index of 1.57, an inert reaction under long-wave and short-wave UV, and no diagnostic absorption spectrum. These properties were consistent with beryl. Raman analysis confirmed the material was beryl.

Figure 2. The observed asterism was due to oriented iridescent needle inclusions. Several dark intersecting lines with lower relief are from the hexagonal growth structure of beryl. Photomicrograph by Tinh Xuan Nguyen; field of view 0.5 mm.

Figure 3. Multiple parting planes, illustrated by parallel lines lying perpendicular to the c-axis, represent the differing concentrations of oriented needle inclusions occurring during growth. Photomicrograph by Tinh Xuan Nguyen; field of view 0.5 mm.
Under the microscope, we observed numerous needle inclusions oriented perpendicular to the c -axis and parallel to the three a-axes, which caused the asterism (figure 2). Moreover, the needles were concentrated as layers, forming multiple parting planes (figure 3) parallel to the basal pinacoid plane in all beads. This parting, combined with the presence of twelve-rayed stars, suggested that the growth orientation of this beryl was changing during the growth process. Additionally, the samples also showed an intersecting structure (figure 2) with angles of 120°/60° that resembled part of the hexagonal growth structure previously observed on the pinacoid of an aquamarine (Spring 2022 G&G Micro-World, pp. 70–71). This structure highlights that the asterism is oriented perpendicular to the c -axis, allowing the easy determination of this direction in translucent to opaque beryl. @chapter:19 @chapter:0 @chapter:19


# Publication Year: 2021
# Title: Yellow Fluid Inclusions in Transparent Sodalite
# Abstract: Figure 1. This 7.17 ct colorless sodalite was remarkably transparent and contained interesting fluid inclusions. Photo by Sean-Andrew Z. Pyle.

The authors recently examined a 7.17 ct transparent, near-colorless sodalite submitted for identification service (figure 1). Sodalite is typically encountered as a semitransparent to opaque, violetish blue stone with white calcite veining resembling lapis lazuli.
Hackmanite is the sulfur-bearing variety of sodalite exhibiting tenebrescence (D. Kondo and D. Beaton, “Hackmanite/sodalite from Myanmar and Afghanistan,” Spring 2009 G&G, pp. 38–43). Tenebrescent minerals reversibly change color when exposed to UV light—from light purple to saturated purple, in the case of hackmanite. While this stone showed the strong orange fluorescence reportedly found in hackmanite, no change in color was observed. This was perhaps due to the short exposure time during testing.

Figure 2. These greenish yellow fluid inclusions were identified as hydrogen sulfide in solution. The gas bubble was matched to hydrogen sulfide gas. Photomicrograph by Tyler E. Smith: field of view 1.99 mm.
Microscopic observation revealed greenish yellow two-phase fluid inclusions reminiscent of petroleum in quartz (figure 2). Unlike petroleum in quartz, the fluid inclusions were inert to long-wave UV light. Raman spectra of the gas bubble and surrounding liquid were matched to gaseous hydrogen sulfide and hydrogen sulfide in solution, respectively. Methane-related peaks were also present in the liquid phase. These sulfur-rich fluid inclusions provided interesting geological evidence of the stone’s formation, making this rare sodalite even more exceptional. @chapter:15 @chapter:0 @chapter:15


# Publication Year: 2022
# Title: Grossular with Strong Red Fluorescence
# Abstract: Figure 1. The 9.63 ct pink grossular garnet reportedly from Mogok (A) fluoresced very strong red under long-wave UV (B) and weak chalky red under short-wave UV radiation (C). Photos by Qian Zhang.
The authors recently encountered a pink garnet rough reportedly from Mogok, Myanmar. The garnet was characterized by a light pink color in daylight, and it showed unusual strong red fluorescence under long-wave ultraviolet radiation and a weak chalky red reaction under short-wave UV (figure 1). A previously published report on grossular garnet showed similar fluorescence under long-wave UV, but the short-wave UV reaction was very different (M.S. Krzemnicki, “Pink grossular garnet from Mogok,” Facette, No. 26, 2020, pp. 26).

Raman spectroscopy identified the garnet as grossular. Electron probe microanalysis determined that the composition was consistent with that of nearly pure grossular with major elements of calcium, aluminum, and silicon (Ca3.114Al2.003Si2.883O12), and laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) testing revealed trace elements of titanium, vanadium, manganese, and others (table 1). The pink coloration was due to two weak bands between 470 and 600 nm in the UV/visible absorption spectrum; Geiger et al. (1999) suggested they are related to Mn3+ (C.A. Geiger et al., “Raspberry-red grossular from Sierra de Cruces Range, Coahuila, Mexico,” European Journal of Mineralogy, Vol. 11, No. 6, 1999, pp. 1109–1113).

Figure 2. The photoluminescence spectrum collected on the grossular using 325 nm excitation at 300 K.
A photoluminescence spectrum recorded with 325 nm laser excitation displayed a strong narrow band at 604 nm accompanied by some weaker bands at 583, 595, 617, 631, 645, and 660 nm (figure 2). Gaft et al. (2013, 2022) published two papers about the luminescence of grossular (M. Gaft et al., “Laser-induced time resolved luminescence of natural grossular Ca3Al2(SiO4)3,” Journal of Luminescence, Vol. 137, 2013, pp. 43–53; M. Gaft et al., “Zero-phonon Mn2+ luminescence in natural grossular Ca3Al2(SiO4)3,” Journal of Luminescence, Vol. 248, 2022, article no. 119001). Our result is consistent with their 2022 result. They proposed that such luminescence emission may be related to the presence of Mn2+.

Figure 3. The 3D contour map of the pink grossular’s fluorescence spectrum. The stacked excitation spectra are not scaled or shifted for clarity.
In order to describe the pink grossular fluorescence features in detail, 3D fluorescence spectral data (i.e., excitation-emission mapping or EEM) was collected at room temperature using a Jasco FP-8500 fluorescence spectrometer (figure 3). The excitation wavelengths varied from 350 to 630 nm, with a step size of 1 nm and an excitation bandwidth of 5 nm. The emission spectra were collected from 400 to 680 nm, with the bandwidth set to 2.5 nm and a data interval of 0.1 nm, showing five obvious emission wavelengths at 604, 617, 631, 645, and 660 nm and their corresponding optimal excitation wavelength at 388 nm.
To our knowledge, this is the first time a detailed fluorescence analysis of pink grossular has been documented. @chapter:8 @chapter:0 @chapter:8


# Publication Year: -
# Title: The Job Seeker's Handbook
# Abstract: After many hours of dedicated study at GIA, you’re ready to find your dream job.

But where do you begin? What do you need to do? And how do you stand out from other applicants?

This booklet contains some essential information you’ll need to succeed in your job search. We encourage you to use it as you begin your professional journey.

To download The Job Seeker's Handbook click on "Download PDF" above. @chapter:45 @chapter:3 @chapter:45


# Publication Year: -
# Title: Topaz Care and Cleaning Guide
# Abstract: Topaz ranks 8 on the Mohs haedness 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.

Because of its basal cleavage, topaz requires special care during cutting, polishing, and mounting. It’s not very tough, so a hard blow might split it, and extreme pressure or sharp temperature changes might cause it to break. To reduce the risk of breakage, cutters orient faceted topaz so the cleavage direction is at about a 15-degree angle to the table. Jewelers prefer to set valuable topaz gems in protective mountings. Or they use topaz in pieces that aren’t exposed to too much wear, like pendants and pins.

Topaz rates 8 on the Mohs hardness scale. Its toughness rating is poor due to its cleavage

Stability
High heat or sudden temperature changes can cause breaks in topaz. The gem’s color is generally stable to light, but prolonged exposure to heat or sunlight might cause fading in yellow-to-brown, reddish brown, or dark brown topaz. Topaz is affected only very slightly by chemicals.

Cleaning
It’s important to avoid steam or ultrasound for cleaning topaz: Warm, soapy water works best.

Treatment and durability considerations
Besides irradiation and heat treatment, there is another treatment that involves coating colorless topaz with a microscopic layer of metallic oxide compound. The coating is not very durable. It can resist daily wear and tear, but abrasive cleaners or buffing wheels would remove it. It’s safe to use a mild soap solution.

Despite these care considerations, fine topaz is a beautiful gem that offers a range of warm, attractive colors in large sizes that are often free of visible inclusions or flaws.

	Surface treatment with metallic oxides resulted in the unique look of this ring’s gem, marketed as mystic topaz. - Courtesy Livingstone Jewelry @chapter:27 @chapter:0 @chapter:27


# Publication Year: 2023
# Title: Natural Diamond with Twinning Wisps Resembling a Whale
# Abstract: This round brilliant diamond displays twinning wisps that resemble a whale. Photomicrograph by Nathan Renfro; field of view 2.62 mm.
The authors recently examined a 0.46 ct type Ia round brilliant diamond with SI1 clarity that had surprisingly patterned twinning wisps. When viewed through the table, the twinning wisps resembled a whale (see above). Twin planes can form in diamond when the orientation of the crystal structure changes during growth in the earth’s mantle. Twinning wisps are atomic defects along this plane, found in ~10% of type Ia diamonds (S. Eaton-Magaña et al., “Natural-color D-to-Z diamonds: A crystal-clear perspective,” Fall 2020 G&G, pp. 318–335).
A termination of one of these features just below the pavilion was examined using photoluminescence (PL) mapping at various excitation wavelengths to examine the distribution of atomic-level defects in the crystal lattice. The PL mapping with 455 nm excitation revealed a relative increase in the defect concentrations of the nitrogen-related centers of H3 (NVN0) with zero-phonon line (ZPL) at 503.2 nm and H4 (4N+2V) with ZPL at 495.9 nm; a weak radiation-related defect, the TR12 with ZPL at 469.9 nm was also detected (A.M. Zaitsev, Optical Properties of Diamond, Springer-Verlag, Berlin and Heidelberg, 2001, and references therein). PL mapping using 633 nm excitation revealed that the GR1 (V0; ZPL at 741.2 nm) had a higher Raman-normalized peak area corresponding to the termination of the twinning wisp compared to diamond adjacent to the wisp. The GR1 defect is typically formed by radiation damage of a diamond lattice. Although the GR1 was elevated, we did not observe radiation stains around the twinning wisps. Furthermore, there were no visible changes to the color of the diamond’s fluorescence when exposed to deep ultraviolet luminescence, which can occur with significant radiation exposure.
This stone offers an example of how natural growth processes in diamond can result in microscopic features that occasionally form delightful patterns. @chapter:22 @chapter:1 @chapter:22


# Publication Year: 2004
# Title: Summer 2004 G&G Book Reviews
# Abstract: “Secrets of the Gem Trade: The Connoisseur’s Guide to Precious Gemstones”
By Richard W. Wise, 274 pp., illus., publ. by Brunswick House Press, Lenox, MA, 2003. US$79.95

“The Gem Hunter: True Adventures of an American in Afghanistan”
By Gary W. Bowersox, 505 pp., illus., publ. by Geovision, Inc., Honolulu, HI, 2004. US$29.95

“Gem and Ornamental Materials of Organic Origin”
By Maggie Campbell Pedersen, 268 pp., illus., publ. by Elsevier Butterworth-Heinemann, 2004. US$54.95

To view the full section, download the PDF above. @chapter:33 @chapter:2 @chapter:33


# Publication Year: 2022
# Title: Interesting Set of Blue “Rough” Gemstones
# Abstract: Figure 1. This set consists of a 48.63 ct piece of manmade glass (left), 9.17 and 6.21 ct laboratory-grown sapphires with resin imitation of matrix on the surface (center), and an 8.46 ct natural blue sapphire rough (right). Photo by Annie Haynes.
The selling of simulants and synthetics mixed with parcels of natural stones is an old form of deception. It usually happens close to mines, where inexperienced buyers assume the gemstones come directly from the source—and where advanced testing is likely not available prior to the purchase.
The Carlsbad laboratory recently received a group of four blue rough stones (figure 1) submitted as natural sapphire for identification and origin reports. The largest weighed 48.63 ct and measured approximately 22.88 × 19.67 × 15.19 mm. The material was partially fashioned, with evidence of polish lines on the surfaces. Careful microscopic examination revealed multiple gas bubbles, distinct flow marks associated with blue coloration, and conchoidal fractures. Weak snake pattern bands were observed under the polariscope. The hydrostatic specific gravity was 2.48. These observations suggested a glass imitation, which was confirmed by comparing the infrared spectrum with that of manmade glass.

Figure 2. A resin imitation of matrix on the surface of a laboratory-grown sapphire. Photomicrograph by Najmeh Anjomani; field of view 7.19 mm.
The next two were more convincing imitations of natural sapphire. They weighed 9.17 and 6.21 ct and measured approximately 16.00 ×10.06 × 8.30 mm and 10.31 × 9.38 × 8.71 mm, respectively. Resin that coated the surface (figure 2) resembled matrix composed of natural minerals commonly seen on natural corundum rough. The resin started to melt with the touch of a hot pointer. Brownish materials trapped in cavities resembled iron oxide stains one would expect to see in natural rough. Though difficult to see inside of the stones due to their rough surfaces, a few gas bubbles were observed through a small transparent area. Raman spectroscopy matched corundum, and immersion in water (figure 3) revealed curved blue banding. Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) detected no gallium and revealed trace elements of impurities consistent with synthetic corundum. Hydrostatic specific gravity values were 3.76 and 3.59, respectively. Both values were below the SG of corundum (3.9–4.05), a result of the lower SG of the resin on the surface. Both were reported as laboratory-grown sapphire with a comment stating, “Imitation matrix and resin is present on the surface.”

Figure 3. Curved blue banding visible in the 6.21 ct laboratory-grown sapphire immersed in water. Photo by Najmeh Anjomani.
The last piece of rough was a blue stone weighing 8.46 ct and measuring 13.85 × 9.89 × 7.60 mm. The frosted natural surface made it difficult to see inside the stone, but some natural-looking fingerprints and strong, straight inky blue banding were observed. The Raman spectrum matched with corundum, and a hydrostatic SG of 3.96 confirmed it. The stone was immersed in methylene iodide to confirm the zoning was straight and not curved. Medium chalky blue fluorescence to short-wave UV and a strong 3309 cm–1 series in its Fourier-transform infrared (FTIR) spectrum proved that heat treatment had been applied to the stone. LA-ICP-MS revealed natural chemistry, including about 200 ppma iron and other trace elements such as gallium (~25 ppma), vanadium (~3.5 ppma), magnesium (~35 ppma), chromium (~1.5 ppma), and titanium (~80 ppma). Based on appearance, color zoning, and chemistry, this stone was reported as natural sapphire, heat treated, with Madagascar as the country of origin.
This was an interesting study of how synthetics and simulants can be mixed with their natural counterparts to misrepresent a parcel. However, careful examination and standard gemological testing are usually enough to identify them correctly. @chapter:19 @chapter:0 @chapter:19


# Publication Year: -
# Title: Artistry of a Peruvian Master Gem Carver
# Abstract: Play

Interview with Luis Quispe, Neoart Peru

Luis Quispe, a talented young gemstone carver from Lima, Peru, showcases his eye-popping work in this video. He is the second generation in a 30-year-old fine gem-carving family business that emphasizes the creation of original contemporary styles. His love of design, and of the raw gem materials he shapes, shines through in his every word and gesture.

Among the many gorgeous examples Quispe demonstrates is a “Marine Life” chess set designed by his sister Silvia. One set of chessmen (actually swordfish, carp, seahorses, marlin, and sea turtles) is carved from Tanzanian ruby and Peruvian pink opal, and the other from Afghani lapis lazuli and Brazilian rock crystal. Luis’ own favorite pieces comprise a set of skulls, each with a distinct personality, that he created out of gem materials from around the world: Canadian jade, Angolan aquamarine, Russian obsidian, Brazilian amethyst, and many more.

When asked how long it takes him to come up with the design for a carving, he says that he has to wait until the stones speak to him. He may look at a piece of raw material every day for a year before the stone reveals the perfect design to him; other times it may take only a day. Luis Quispe clearly knows how to speak the language of gemstone carving. @chapter:28 @chapter:2 @chapter:28


# Publication Year: 1992
# Title: Gamma-Ray Spectroscopy to Measure Radioactivity in Gemstones
# Abstract: Over the last several years, the trade has seen a number of radioactive gemstones.  While a Geiger counter may show the existence of radioactivity, determination of the actual type of radionuclide and the quantity present requires a more sophisticated technique, gamma-ray spectroscopy. This article reports on the use of this technique to measure the radionuclides in two radioactive gemstones, a yellowish green diamond and a large dark blue topaz. @chapter:43 @chapter:1 @chapter:43


# Publication Year: 2023
# Title: Saltwater Clamshell Beads (Tridacna Species) Used in Freshwater Cultured Pearls
# Abstract: Figure 1. A strand of baroque-shaped freshwater bead cultured pearls shown with two Tridacna-species mollusk shells from GIA’s shell reference collection. Each sample weighs approximately 20 ct, ranging from 16.73 × 12.58 × 12.49 mm to 18.98 × 13.53 × 13.43 mm. Photo by Nuttapol Kitdee.
GIA’s Bangkok laboratory recently studied 23 intriguing freshwater bead cultured pearls purchased from a vendor in Hong Kong. They displayed an elongated baroque shape with a surface protuberance at one end, and they weighed approximately 20 ct apiece and ranged from 16.73 × 12.58 × 12.49 mm to 18.98 × 13.53 × 13.43 mm (figure 1). Their shape and appearance are similar to saltwater bead cultured pearls known in the market as “Tokki pearls” (A. Homkrajae et al., “Internal structures of known Pinctada maxima pearls: Cultured pearls from operated marine mollusks,” Fall 2021 G&G, pp. 186–205).

Figure 2. RTX imaging revealed shell bead nuclei approximately 12 mm in diameter entirely covered by the pearl’s approximately 1 mm thick nacre (left), with numerous parasite channels in the beads (right).
Real-time microradiography (RTX) revealed the distinct round demarcation of a bead nucleus with additional void and/or linear features in all the samples, as expected from their external appearance (figure 2, left). However, the beads were more radiopaque and appeared lighter gray in RTX imaging than the traditional freshwater shell bead nuclei widely used in both saltwater and freshwater bead cultured pearl production (P. Southgate and J. Lucas, The Pearl Oyster, 2008, p. 286; “Freshwater pearling in Tennessee,” GIA Research News, October 7, 2016; N. Sturman et al., “Vietnam: Shell nuclei, pearl hatcheries, and pearl farming,” Fall 2020 G&G, pp. 402–415). Numerous long, thick parasite tubes were visible within the beads, something not often seen in traditional beads (figure 2, right). Optical X-ray fluorescence imaging was used to verify the pearls’ freshwater origin. They exhibited weak to moderate yellowish green fluorescence, confirming a freshwater origin. However, the reaction was much weaker than many freshwater bead cultured pearls of the same size and nacre thickness previously examined. These unusual characteristics observed in RTX and X-ray fluorescence imaging led us to cut two pearls in half to investigate the bead nuclei.

Figure 3. Left: A cross section with the Tridacna fashioned shell bead nucleus inside showing fine subtle flames in between banded structures. Right: Magnified view of the clamshell bead’s flame structure. Photomicrographs by Kwanreun Lawanwong; fields of view 19.20 mm (left) and 7.20 mm (right).
The cross sections revealed bead nuclei approximately 12 mm in diameter. The beads appeared chalky white and opaque, unlike traditional beads that are commonly white to cream-colored and semitranslucent. Moreover, the beads exhibited a porcelain-like texture and a subtle flame pattern. We ground the surface of two additional samples to better understand the material. Banded structures of shell formation with subtle flame structures in between were present (figure 3).

Figure 4. An X-ray illuminated cross section produced a strong yellowish green fluorescence reaction on the freshwater pearl’s outermost surface nacre layer, while the inner rounded saltwater clamshell beads showed an inert reaction.
Energy-dispersive X-ray fluorescence was used to analyze the elemental concentration of the outer nacre layer and the bead nuclei. The nacre layer showed a high level of manganese and low strontium content, confirming the pearls formed in a freshwater environment. Conversely, the bead nuclei showed high strontium (around 1000 ppm) and no manganese was detected, which are typical results for pearls from a saltwater environment. X-ray fluorescence imaging of the cross section displayed a strong yellowish green reaction on the freshwater nacre due to high manganese content, while the saltwater bead nuclei were inert (figure 4). A Raman spectrometer with 514 nm argon-ion laser excitation was employed to analyze the bead nuclei composition, and double peaks at 701 and 705 cm–1 and a single peak at 1085 cm–1 of aragonite were recorded. Aragonite is a common component of shell and pearl.
The large size, white color, porcelain surface appearance, banded structure with flames, saltwater formation environment, and aragonite composition of the bead nuclei suggested they were created from the clamshell of Tridacna-species mollusks. Fashioned shells from Tridacna species have been applied particularly in pearl imitations (see Summer 2014 Lab Notes, pp. 153–154; Spring 2015 Lab Notes, pp. 62–63) but are not commonly used in culturing because they are easily broken during the drilling process. More importantly, shells from Tridacna species should be avoided for jewelry items or decoration since they are protected by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), the international agreement that protects endangered species. @chapter:11 @chapter:4 @chapter:11


# Publication Year: 1989
# Title: Summer 1989 G&G Lab Notes
# Abstract: Phenomenal Chrysoberyl
"Coated" Diamond
Diamond Cube with Cloud-Like Inclusion
Fancy Intense Yellow Diamond with a Green Irradiation Stain
Irradiated Diamond Rough
Emerald with Plastic-Like Filling
Imitation Lapis Lazuli
X-ray Transparency Separates Two Lapis Lazuli Imitations
Cherrystone Clam "Pearl"
Natural Color Ruby
An Unusual Zircon

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