Publication Year: - Title: Diamond History and Lore Abstract: Diamonds have a long history as beautiful objects of desire. In the first century AD, the Roman naturalist Pliny stated: “Diamond is the most valuable, not only of precious stones, but of all things in this world.”

A diamond has to go through a lot before it reaches the jeweler’s display case. It forms deep in the earth under extreme heat and pressure. It’s ejected violently upward until it arrives at or near the earth’s surface. It’s forced from its hiding place by nature or by man. Then it’s cleaved and cut and polished until its natural beauty shines through.

The world’s love of diamonds had its start in India, where diamonds were gathered from the country’s rivers and streams. Some historians estimate that India was trading in diamonds as early as the fourth century BC. The country’s resources yielded limited quantities for an equally limited market: India’s very wealthy classes. Gradually, though, this changed. Indian diamonds found their way, along with other exotic merchandise, to Western Europe in the caravans that traveled to Venice’s medieval markets. By the 1400s, diamonds were becoming fashionable accessories for Europe’s elite.

In the early 1700s, as India’s diamond supplies began to decline, Brazil emerged as an important source. Diamonds were discovered in the pans of gold miners as they sifted through the gravels of local rivers. Once it reached its full potential, Brazil dominated the diamond market for more than 150 years.

While sources changed, the diamond market experienced its own evolution. The old ruling classes—diamonds’ biggest consumers—were in decline by the late 1700s. Political upheavals like the French Revolution led to changes in the distribution of wealth.

The 1800s brought increasing affluence to western Europe and the United States. Explorers unearthed the first great South African diamond deposits in the late 1800s just as diamond demand broadened.

	By the early 1900s, De Beers controlled about 90 percent of the world’s production of rough diamonds. - Courtesy De Beers
The story of the modern diamond market really begins on the African continent, with the 1866 discovery of diamonds in Kimberley, South Africa. Entrepreneur Cecil Rhodes established De Beers Consolidated Mines Limited 22 years later, in 1888. By 1900, De Beers, through its mines in South Africa, controlled an estimated 90 percent of the world’s production of rough diamonds.

The South African sources affected many segments of the diamond industry. This was especially true as diamond mining moved from the surface to farther underground. Because of the huge costs and comparatively low yields involved, the new sources forced the development of more efficient mining techniques. They created the need for better marketing. They also led to advances in cutting and polishing—advances that increased efficiency, reduced costs, and enhanced the appearance of finished stones.

In the 1870s, annual production of rough diamond was well under a million carats. By the 1920s, the figure was around three million carats. Fifty years later, annual production approached 50 million carats, and in the 1990s it surpassed 100 million carats per year.

At the end of the 1970s, the world’s most important rough diamond producers were South Africa, Zaire (now renamed the Democratic Republic of Congo), and the former Soviet Union. In the 1980s, output of higher-quality diamonds from Russia and South Africa remained relatively constant, but Zaire’s production of lower-quality diamonds more than doubled.

In 1982, a highly productive new mine in Botswana added to world production. A prolific source of high-quality diamonds, the Jwaneng mine boosted Botswana’s production so much that the country rose to third in the world in total diamond recovery, and second in diamond value. De Beers contracted with Botswana’s government to buy the mine’s production and Botswana set out to build its own diamond-cutting industry.

World diamond mining expanded dramatically with the discovery of sources in Australia in 1985 and important new deposits in northern Canada in 2000.

The market probably changed as much after 1990 as it did in the years after the 1866 discovery of diamonds in South Africa and the establishment of De Beers. The 1990s brought exciting new sources and encouraged the dramatic growth of some cutting centers. All this was happening as the world economy fluctuated wildly.

As one of the trade’s major participants, De Beers had to change, too. The De Beers of today bears little resemblance to the De Beers of 1989. The company greatly reduced its role as the custodian of diamond supply. Instead of flowing into the market in a single-channel path from De Beers, diamonds now flow into the market through multiple channels.

Not everything changed, though. Regardless of the path they take, diamonds still flow from mines through cutting centers, and ultimately to retail customers.

Diamond’s splendor has been appreciated for centuries, but there was not much scientific knowledge about it before the twentieth century. Since then, diamond knowledge has grown steadily, with research by chemists, physicists, geologists, mineralogists, and oceanographers. In the past 50 years alone, scientists have learned a lot about how diamonds form and how they’re transported to the earth’s surface. That knowledge has made it easier to predict locations for new diamond discoveries.

	The mystique and prestige of diamonds has made them desired around the world to adorn jewelry and watches. - © GIA & Tino Hammid, courtesy Suzanne Tennenbaum @chapter:28


Publication Year: 2019 Title: Helical Inclusion in Colombian Emerald Abstract: A three-dimensional helical inclusion in emerald. Photomicrograph by Taku Okada; field of view 2.93 mm.

GIA’s Tokyo laboratory recently examined a 7.54 ct natural emerald containing a 3D helical inclusion (see above) resembling a DNA double helix or fish bone. This helix, consisting of whitish grains, reached the emerald’s surface. The other associated inclusions were jagged three-phase fingerprints, growth tubes, and the gota de aceite optical effect (R. Ringsrud, “Gota de aceite: Nomenclature for the finest Colombian emeralds,” Fall 2008 G&G, pp. 242–245). All these features supported a Colombian origin. To date, three emeralds examined in GIA’s Tokyo laboratory that were reportedly Colombian have exhibited similar inclusions. This helical inclusion may therefore be a characteristic of Colombian emeralds. Such a discovery within a stone is always pleasing. @chapter:9


Publication Year: - Title: Tiny Inclusions Reveal Diamond Age and Earth’s History: Research at the Carnegie Institution Abstract: This sharp-edged octahedral diamond crystal nestles in kimberlite, the rock that brought it to the earth’s surface. Such crystals may preserve minerals from deep in the mantle and provide a record of temperature and pressure conditions there. Robert Weldon © GIA

                      For Dr. Steven Shirey, diamonds are very special. Not merely for their intrinsic beauty, but for the fundamental information locked within them. Information that illuminates the earth’s early history and the planet’s structure at depths hundreds of kilometers beneath our feet.

We’ve traveled to the Carnegie Institution of Washington—more specifically the Institution’s Department of Terrestrial Magnetism—to document Dr. Shirey’s work on determining the age of diamonds from many mines around the world by analyzing the tiny mineral inclusions preserved within them.

	Dr. Steven Shirey, a senior scientist at the Carnegie Institution of Washington’s Department of Terrestrial Magnetism, has a special interest in diamond—it’s his best method of glimpsing the unimaginable pressures and temperatures of the deep earth’s interior. Duncan Pay © GIA, courtesy Carnegie Institution of Washington
“Let me try to place into a broader context what the good of this diamond work is,” Shirey begins. “One of my personal goals is to take the knowledge of the age of the diamond, and the initial ratios we get from these inclusion studies and put them into the big geological picture in a systematic way. I want to look at how diamonds are distributed across continental terranes with regard to how the continent was put together.”

“I want to go back in Earth’s history to see if the pattern of diamond growth and diamond history tells us anything unique about the evolution of Earth as a planet,” Shirey says. “In itself that’s a pretty amazing concept. We’re taking these tiny grains—very, very small—and using the systematic change in chemistry to say something about our entire planet.”

	In ancient continental areas, there’s a significant keel, or downward protrusion into the mantle, where conditions are stable enough to preserve diamonds for many hundreds of millions of years. Recent discoveries show that diamonds might form beneath subduction zones at great depths, and that very rarely plumes in the earth’s mantle move them up to where kimberlites can bring them to the earth’s surface. These “superdeep” diamonds provide Shirey and other scientists a tantalizing window into the workings of the deeper mantle. Peter Johnston © GIA
This article complements the winter 2013 Gems & Gemology paper “Recent Advances in Understanding the Geology of Diamond,” coauthored by Shirey and GIA’s Dr. Jim Shigley.

Shirey is a one of a collaborative group of geoscientists from institutions all over the world using diamonds as a means to sample the deep earth. His particular specialty involves seeking out the rare individual diamonds that contain tiny and specific sulfide inclusions, painstakingly removing the inclusions and analyzing their contents—in this case, trace amounts of the radioactive isotopes of the rare metals osmium (Os) and rhenium (Re)—to determine ages on the order of billions of years.

An isotope of a chemical element is simply an atom with the same atomic number as that element, but with a slightly different mass, resulting from a different number of neutrons in its nucleus. Some isotopes are stable, but others—called radionuclides—emit radiation and decay into different isotopes over long periods of time. If scientists know the rate of radioactive decay, and have instrumentation capable of measuring the different isotopes present, they can calculate the age of an item very accurately.

This is the principle behind long-established techniques such as radiocarbon dating, which has been widely used in archaeology. Diamonds are vastly older than any archeological relic, so carbon dating—which can only date items back to around 60,000 years ago—isn’t possible.

The isotopes Shirey seeks provide a much longer reach back into the earth’s history. These radioactive isotopes are like tiny, slow-ticking clocks captured in the fabric of a diamond crystal. They decay very slowly over eons, with very long half-lives (the time it takes for a substance’s radiation to fall to half its original level). The isotope of rhenium he uses, 187Re, decays into osmium (187Os) very slowly, with a half-life of 41.6 x 109 years, or 41 billion years.

Research using the rhenium-osmium decay system proves that some diamonds are of remarkable antiquity, says Shirey. “They’re sometimes the oldest minerals we can find on the earth…up to 3.5 billion years old, whereas the earth is only 4.5 billion years old, so they’re often three-quarters of the age of the earth.”

Shirey adds that diamonds are also special because they’re the deepest minerals we can obtain as natural samples to study the earth. Unlike any other mineral, diamonds reach the surface from great depths—up to 700 kilometers (435 miles) beneath the earth’s surface—and may retain unaltered inclusions of mantle minerals within them. A diamond crystal is a “really good container” for these exotic minerals, he says, and preserves them in “pristine” form on the way to the earth’s surface.

“So in one mineral species,” he says, “you have the deepest, the oldest, and the most resistant to secondary effects mineral that you can get, so it makes them very, very unique specimens.”

	Dating Diamonds

	Dr. Shirey explains the study of radiogenic isotopes hidden inside individual diamond inclusions to determine their age and hence the age of the diamonds themselves.
Shirey tells us that the osmium-rhenium radioactive decay system allows researchers to date individual inclusions. Previous dating techniques required researchers to collect inclusions of other minerals—including garnets and zircon—from many different diamonds to obtain an age. If there was more than one generation of diamonds in the sample, you’d end up with an average age rather than the specific age.

View Gallery

	This slideshow takes you through the processes Dr. Shirey uses to select natural diamonds for research and extract the sulfide inclusions from them to obtain accurate ages—often in the range of billions of years. It involves ingenious solutions to fashion the tiny diamonds into plates for study, cleave out the sulfides, separate the isotopes of rhenium and osmium by chemistry, and count the various isotopes with sophisticated laboratory instrumentation for the final age determination.

	Selecting Diamonds for Study
The process begins with suitable inclusion-bearing diamond crystals. As Shirey tells us, obtaining such diamonds for study is quite a challenge. “We have to go to a mine or some place that’s being very aggressively prospected so that they’re processing large amounts of kimberlite for diamond grade.”

Diamonds are trace minerals in the rock—kimberlite, or more rarely a lamproite as in Australia’s Argyle mine—that carried them up from the mantle. “A diamond in a kimberlite occurs at the part-per-billion level,” says Shirey, “so the average person walking around on a kimberlite is not going to find a diamond sitting there—that’s an extremely rare occurrence.”

	This diamond crystal, from Lesotho’s Letseng mine, contains a sulfide inclusion suitable for Shirey’s research. Pedro Padua © GIA, courtesy Carnegie Institution of Washington
Once researchers have traveled to suitable mining or exploration operations, where large amounts of diamond-bearing ore are produced, they have to pick through the production. Even at a mine as large as South Africa’s Venetia, only 1 in 50,000 diamonds produced might harbor the right kind of inclusion.

“In this case we’re seeking the rejects of the gem trade,” says Shirey. “Most mines have a very low frequency of inclusion-bearing diamonds to gem-quality diamonds, and so in some mines it’s almost impossible to get inclusion-bearing stones.”

	These diamond crystals, which bear sulfide inclusions decorated by rosette fracture systems, are suitable candidates for dating using the rhenium-osmium decay system. Pedro Padua © GIA, courtesy Carnegie Institution of Washington

	Preparing the Diamond for Research
Once the researchers have enough inclusion-bearing diamonds for a valid study, work can begin. “We have to get the inclusion out without breaking it,” says Shirey. “We need to recover the whole inclusion, and we also need to characterize the diamond as fully as possible.

“Our job is not just to measure the isotope composition of the inclusion, but also to get the whole picture of how the diamond formed, before we end up destroying the diamond to get the inclusion out.”

The first step is to slice the diamond very precisely across its growth zones using a diamond-cutting laser. “It would probably drive everybody in the gem business crazy to understand that we take a beautiful rough diamond and slice the center out of it,” says Shirey with a wry smile.

	Shirey designed this jig for laser cutting the diamond crystals. Duncan Pay © GIA, courtesy Carnegie Institution of Washington
“I actually had to design a device, and I went to the shop and asked if they could make it for me. And they turned it out in a day or two. We brought it back to the laser cutter and set it up, and the guys that owned the laser cutter liked it so much. It’s a little jig that has some thumbscrews that hold the diamond, just in perfect position to cut it—zip, zip, without having to reorient it—and cut three at a time.”

The wafer, with the inclusion in the middle of it, is then polished on a conventional diamond scaife. Great care must be taken to ensure the inclusions aren’t compromised or contaminated by the cutting and polishing process.

This yields a precisely oriented polished diamond plate, typically about a millimeter deep, that shows the inclusion’s position relative to the host diamond’s growth zoning. The diamond’s growth zones are especially visible using cathodoluminescence (CL) imaging. CL imaging reveals whether the diamond has a straightforward or more complex growth history.

Shirey’s colleague Dr. Jianhu Wang can also investigate the diamond plate’s isotopic composition using a secondary ion mass spectrometer (SIMS) or ion probe. The SIMS instrument allows detailed chemical analysis of the diamond’s growth zones. It can measure differences between the carbon or nitrogen isotopes across a diamond, which can establish whether the stone has a unique geologic history and what the data from the inclusion means. We will spotlight Dr. Wang’s work in a future Research & News article on the GIA website.

	Preparing Diamonds for Study

	In this sequence of videos, Dr. Shirey explains how researchers select and prepare suitable inclusion-bearing diamonds for study. The process begins with crystals that are polished into precisely oriented plates for analysis. It ends with the plates being cleaved in a specially designed “diamond cracker” to recover their sulfide inclusions for age determination using chemistry.

	Removing the Inclusion from the Diamond
Selecting, documenting, and gathering analytical data on a single diamond plate might take many weeks. From this data, however, researchers gain valuable insight into a diamond’s growth history.

At some point, though, the sulfide inclusions have to be removed from the plate for researchers to determine their age. This is the “lowest-tech” point of the process. It’s accomplished using a device Shirey calls the “diamond cracker.” This is a thick-walled hollow steel cylinder with a lid containing a piston. The diamond plate sits over a pair of tungsten carbine lathe bits, which form a platform. Shirey orients the diamond plate within the cylinder so that the portion with the inclusion lies above the gap between the two lathe bits.

On the inside of the cylinder’s lid, there’s a tungsten carbide rod bonded to the surface. Grooves inscribed on the cylinder base and the side of the lid help Shirey align it so that the rod is directly parallel and above the gap between the two tungsten carbide lathe bits in the cylinder base.

Shirey adjusts the piston in the lid so that there’s just enough play to contact the diamond without crushing it. A sharp tap on the top of the piston with a small hammer cleaves the diamond in the plane of the sulfide inclusion, releasing it.

Next, Shirey has to painstakingly search the cylinder’s interior for the inclusion. It’s often tough to find among the shards of diamond and tiny metal fragments from the tungsten carbide components or the steel wall of the diamond cracker. “The inclusion is often 100–300 microns…sometimes it’s 50 microns,” Shirey says. (One centimeter = 10,000 microns, so even a 300-micron inclusion is only 0.03 centimeters across—just 0.3 of a millimeter!)

	The tiny reflective speck at the center of the black disk is a sulfide inclusion, which has been cleaved out of a diamond plate using the “diamond cracker.” Hidden inside this tiny speck are traces of the rare elements rhenium and osmium. Pedro Padua © GIA, courtesy Carnegie Institution of Washington
At that size, simply moving the inclusion can be a big challenge: “That’s so small that static forces make it almost impossible to move the inclusion around, and so we have to be very careful not to lose the inclusion,” Shirey continues with a chuckle. “There have been times when I dropped the inclusion in the sink, and I had no recourse but to take the trap off the sink and drain the trap and start looking through all the junk in the trap, because I had so much time invested in the inclusion.”

Once Shirey recovers the inclusion, it’s transferred to a sticky black carbon disk and examined under a scanning electron microscope (SEM) to make sure it’s a sulfide inclusion and not a piece of steel or tungsten carbide from the cracker. Unlike those materials, sulfides look a little “brassy” or yellowish.

He’ll also examine the sulfide for traces of growth morphology and crystallography. Mineral inclusions can tell researchers a lot about the temperature and pressure conditions in which a diamond formed, the rocks and fluids it grew from, and whether it formed at the same time as its diamond host.

Shirey also wants to determine whether the sulfide is from an eclogitic or peridotitic source rock. Peridotitic sulfides contain higher levels of nickel and lower levels of iron. It’s important to make the distinction, Shirey tells us, because that will decide the composition of the special tracer he uses in the “wet” stage of the analysis.

His next step is to wash and rinse the inclusion with ethanol in a tiny beaker, in preparation for weighing it in an extremely sensitive electronic balance. He then carefully picks up the inclusion with a needle and transfers it to a little foil weighing boat that itself weighs a fraction of a milligram.

The weight of the inclusion is especially important, because it controls the exact amount of a special chemical tracer—called a “spike”—that Shirey has to add for the next stage of the work. The spike contains a precisely calibrated mixture of different isotopes of rhenium and osmium.

This is a standard procedure, much used in geochemistry, called isotope dilution. The sulfide inclusion contains tiny amounts of a radioactive isotope of rhenium (187Re), which decays extremely slowly over many billions of years to a stable isotope of osmium (187Os). As the rate of radioactive decay is known, it’s possible to calculate the age of the diamond based on the ratios of 187Re and 187Os present.

Isotope dilution allows researchers to estimate the amount of rhenium and osmium isotopes present—to a very high degree of accuracy—by adding a precisely calibrated solution of different isotopes of each element—the spike—and mixing it very thoroughly with the rhenium and osmium in the inclusion.

Because Shirey knows the weight of the inclusion and the exact amount of spike added, he can calculate the amounts of each rhenium and osmium isotope present from their ratios at the end of the chemistry process without having to recover everything.

Here’s an illustration of the principle behind isotope dilution: Imagine you have a large cardboard box filled with a mixture of white and a smaller number of orange Ping-Pong balls. In this simplified analogy, the cardboard box is the inclusion, the orange balls represent the osmium isotope we want to count, and the white balls stand in for everything else in the inclusion (in other words, the “matrix”).

You can calculate the number of orange balls to the highest degree of accuracy possible without counting every single one. One way is to add a known number of blue Ping-Pong balls—say 100—and mix them thoroughly with all the rest. These blue balls represent the chemical spike.

Once you’re sure all the balls are thoroughly mixed, or diluted with the other colors, take a sample of 50 balls out of the box and count the number of blue ones. From this sample, you can work out the ratio of blue balls to the total number of Ping-Pong balls in the box, as well as the orange ones you need to count. From that information, you can calculate the totals for each color very accurately. Exactly the same principle applies to the isotopes of rhenium and osmium in a diamond inclusion.

After weighing the inclusion, and adding a precisely calibrated amount of the spike, Shirey adds acid to dissolve the inclusion and thoroughly mix its constituents together with the spike.

	Separating Rhenium and Osmium

	This sequence of videos starts with Dr. Shirey weighing the sulfide inclusion recovered from the diamond. Next, he takes us through the chemistry necessary to separate the radiogenic isotopes of osmium and rhenium from the inclusion for age dating.
Once the acid has dissolved the inclusion, Shirey has to distill out the osmium and rhenium content. With osmium, this is pretty straightforward: “We distill it by vapor transport to a little button of hydrobromic acid, and the rhenium will stay back in a drop of chromic sulfuric.”

The rhenium requires a little more work: “We take this chromic sulfuric out, we reduce it, and it will go from brick red to green, and we put it then through an anion exchange column, which is like a Brita filter, but cleaned up and perfect for our work. And what it’ll do is pass everything through the column, retaining the rhenium.”

Shirey then takes the rhenium from the column and dries it down to prepare it for analysis. Now that the osmium and rhenium are separated, he can begin the final part of the process, which is to run both on sophisticated laboratory instruments called mass spectrometers. To avoid any cross contamination, each metal is run on a separate instrument, which counts the different isotopes—or masses—of each element. Shirey tells us, with something akin to relief, “From that we have the isotopic composition, and we can calculate the age…and that’s the end of the work.”

“So we do that on every inclusion,” he adds, “as long as it’s big enough to move around so that we can do the distillation—and from that, believe it or not, we get the age.”

The rhenium-osmium decay system plots as a line on a graph. Each inclusion plots as a data point, on or very close to the line.

	Researchers use the proportion of rhenium and osmium isotopes in each sulfide inclusion
	to plot a line called an isochron, which measures the decay of 187Re to187Os. Each data
	point represents an age from an inclusion and its diamond host. These diamonds from
	Canada’s Ekati mine are the oldest yet known, at 3.523 billion years (3523 Ma on the
	graph)—an astonishing age, when the earth was a quarter of its age today. The inset at
	right shows detail from the lower end of the isochron.Adapted from Westerlund (2006);
	see the Winter 2013 Gems & Gemology, figure 24, p. 211.

	Using Mass Spectroscopy

	In this video, Dr. Shirey explains the use of mass spectrometry to count the isotopes of osmium and rhenium recovered from the sulfide inclusion. This is the final stage of the analysis that began with selecting diamond crystals with suitable sulfide inclusions from working mines. Shirey and his colleagues will use the data captured on the relative amounts of each isotope to determine the age of the inclusion and therefore the diamond itself.

	Results from Research
Shirey reckons his biggest contribution to this research area, with his Carnegie colleagues, is development of the rhenium-osmium dating system, which allows dating of individual diamonds. The ages of the diamonds and the chemistry of their inclusions allow researchers to make inferences about the way continents are built and the onset of the earth’s tectonic processes.

Shirey’s early work with diamonds focused on one of the world’s best known mining areas, the ancient rocks at the heart of southern Africa, and De Beers’s mining empire: the Kaapvaal craton. The pattern of diamond occurrences and their ages from east to west across the landscape spoke to him about the structure of the deeper continent beneath his feet.

“What really turns me on about it is taking individual diamond measurements and putting them together in a large picture, so that the age distribution would tell us something fundamental on the scale of a continent—or something fundamental on the scale of the earth and a billion-year type of time history. That’s what really gets me excited,” he says.

In the case of the Kaapvaal craton, the diamonds tell Shirey that something changed in the earth’s history about three billion years ago. He and his colleagues propose that this marks the onset of what’s called the Wilson Cycle, the beginning of plate tectonics and subduction of oceanic crust. At the center of the craton lies the graveyard of an ancient ocean that closed when two continental blocks collided—one from the east and one from the west. And the diamonds in the west are different from the ones in the east.

All of the three-billion-year-old diamonds are on the west side of the craton, which agrees with Shirey’s theory about subduction of oceanic crust under the west side. By contrast, there are no diamonds older than three billion years east of the junction—or suture—between these two ancient continental blocks, “and that perfectly explains the type of diamond distribution that you see,” says Shirey.

Shirey explains that diamonds older than three billion years completely lack eclogitic inclusions. This means basalt from subducted oceanic crust had not been thrust deeply enough under the continental keel to be retained and converted into eclogite—a high-pressure metamorphic rock that hosts diamonds. After this date, scientists start to see diamonds with these types of inclusions. And that’s a big important discovery,” says Shirey.

	Canadian Diamonds Are Ancient
Another landmark discovery relates to the age of Canadian diamonds. Shirey notes that his group at Carnegie has worked on the country’s two biggest mines, Ekati and Diavik. A Ph.D. student studying Ekati’s diamonds discovered they were the oldest diamonds yet analyzed, at around 3.5 billion years old.

The chemistry of these Ekati diamonds indicated an early form of subduction. Shirey and his fellow scientists at Carnegie suggest that the subduction process forming them represents some of the earliest evidence of plate tectonics on the surface of the earth. Shirey mentions that another Ph.D. student working on diamonds from Diavik corroborated their ancient age, but found evidence they were sourced from a deep-seated plume in the earth’s mantle.

“What’s unique about the Canadian occurrences that we’ve looked at so far is their antiquity and the fact that they give us a complicated story,” says Shirey. “We think that there was more than one process to make diamonds in this early Archean period, and that’s actually a very interesting and exciting discovery.”

	Superdeep Diamonds from Brazil’s Juina Field
Superdeep diamonds are one of the most exciting finds of the last 15 years, says Shirey. These diamonds carry minerals in them that aren’t found at shallower levels, including high-pressure forms of garnet and olivine that cannot form at shallower depths. The hypothesis is that these diamonds grow from organic material carried down as deep as 700 km into the mantle by subduction. They also have a characteristic irregular internal growth structure that hints at their turbulent origin deep in the earth’s convecting mantle. Superdeep diamonds sample the earth’s mantle at greater depths than scientists have seen before, and they will undoubtedly provide insight about the way the earth recycles carbon. Shirey and a number of his Carnegie colleagues are actively collaborating with researchers at other institutions on this topic. For more details, please see his Carnegie page on superdeep diamonds and mantle convection.

	These tiny superdeep diamonds formed at significantly greater depths in the earth’s mantle than most diamonds. Here, they’re mounted for analysis in an electron microprobe. Pedro Padua © GIA, courtesy Carnegie Institution of Washington

	Rewards of the Job
Shirey tells us he loves his work because it’s so diverse: “I get to go in the field, to talk to geologists. I get to take specimens and take them apart, to design ways to cut the smallest diamonds.”

These challenges stimulate Shirey: “It’s being inventive and crafty, when it comes to manipulating the specimens, but I have to be a chemist as well—I actually had to do the development work on the chemistry. It’s all so different, which is one of the reasons I love doing what I do.”

In the end, he realizes that all this work passes for naught if it’s not communicated in a way that engages the audience. “We have to write the stuff up, communicate our results and tell the story in a way that people find interesting. At the end of the day, if no one wants to hear what you have to say, it doesn’t do any good. So if you don’t make the story interesting, no one’s going to read it.”

Shirey reminds us that research work of this kind is highly collaborative, involving scientists from different disciplines and many partner institutions around the world. He is modest about his contributions. “Most of the work is not done directly by me, but by people that I work with. Almost all the work is done by visitors to the lab, or postdocs that we’re trying to train.

“That’s actually a fun part about my job,” he continues, “I get to be a teacher and a mentor, and that turns out to be a lot of fun.” @chapter:29


Publication Year: 2007 Title: Durability Testing of Filled Emeralds Abstract: Researchers treated 128 emeralds with nine emerald fillers—Araldite 6010, cedarwood oil, paraffin oil, unhardened and surface-hardened Opticon, a mixture of cedarwood oil and Canada balsam, surface-hardened Norland Optical Adhesive 65, and the solid fillers Gematrat and Permasafe—and then exposed them (along with 14 unfilled emeralds) to common conditions of wear and cleaning. All emeralds were held for about six years, and most were then subjected to one of the following durability tests: exposure to long-wave UV radiation (a component of sunlight), to mild heat and incandescent light in a display case, to five chill-thaw cycles, and to a desiccation environment; ultrasonic cleaning with either warm water or BCR; and cleaning with steam or mild chemical solvents. Changes were evident in about 35% of the filled emeralds after the mild exposure tests (i.e., time, UV radiation, display case); those with liquid fillers were especially susceptible. The desiccation environment made fissures visible in a majority of emeralds. Hard fillers damaged their host emeralds by expanding cracks during durability testing, while chill-thaw cycling extended cracks in both filled and unfilled emeralds. Emeralds with liquid fillers were most susceptible to appearance changes due to ultrasonic cleaning and exposure to ethanol or acetone. Some observations on the effectiveness of different fillers on emerald appearance are also provided. @chapter:17


Publication Year: 1991 Title: Fall 1991 G&G Book Reviews Abstract: “Gemology, 2nd Edition”
By Cornelius S. Hurlbut and Robert C. Kammerling, 337 pp., illus., publ. by John Wiley & Sons, New York, 1991. US$58.00

“Gemstones of Pakistan: Geology and Gemmology”
By Ali H. Kazmi and Michael O'Donoghue, 146 pp., illus., publ. by Gemstone Corporation of Pakistan, Karachi, Pakistan, 1990. US$24.95

“Gems, Granites, and Gravels, Knowing and Using Rocks and Minerals”
By Richard V. Dietrich and Brian J. Skinner, 173 pp., illus., publ. by Cambridge University Press, New York, NY, 1990. US$24.95

“Crystals”
By Ian F. Mercer, 60 pp., illus., publ. by the Harvard University Press, Cambridge, MA, 1990. US$9.95

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


Publication Year: 2017 Title: A Review of HPHT Synthetic Diamonds Grown forJewelry Use Abstract: Our Fall issue serves up a wealth of topics, including HPHT synthetic diamonds, historical saltwater pearls from the New World, the photoluminescence (PL) spectra of emeralds, synthetic star corundum, and the Colombian emerald mine-to-market industry.

HPHT synthetic diamonds—including blue and colorless gems exceeding 10 carats along with mass-produced melee—are now a marketplace reality...

In our lead article, Drs. Sally Eaton-Magaña, James Shigley, and Christopher M. Breeding present a comprehensive study of several thousand HPHT-grown synthetic diamonds using data gathered by GIA between 2007 and 2016. Their study charts a transition from predominately orange-yellow goods to today’s more diverse products, where fashioned blue and colorless synthetics exceeding 10 carats and mass-produced HPHT melee grown exclusively for jewelry use are now a marketplace reality. We trust that this survey—which includes a review of current identification criteria for HPHT-grown synthetics—will prove immensely valuable for industry professionals.

The second paper is a collaboration between researchers at GIA and the Gübelin Gem Lab. Lead author Chunhui Zhou and his team detail 85 natural saltwater pearls reportedly recovered from Caribbean waters between the fifteenth and seventeenth centuries. The team’s analyses verified these fascinating pearls’ natural saltwater origin, and 14C isotope radiocarbon dating supports their attested age.

In the first of this issue’s two emerald papers, researchers led by Dr. D. Brian Thompson of the University of North Alabama investigate the PL spectra of 48 samples from Colombia, Afghanistan, and Zambia. Their research strongly indicates that variations in trace element concentration within emeralds from these localities correlate with differences in the strength and position of peaks detected in their PL spectra, which could be very promising for determining geographic source.

In our fourth paper, Dr. Karl Schmetzer, Prof. H. Albert Gilg, and Dr. Heinz-Jürgen Bernhardt delve into the characteristics of synthetic star corundum produced in Germany up to the 1970s by Wiede’s Carbidwerk. Grown by a variation of the Verneuil method followed by controlled annealing to exsolve the rutile needles, these synthetic gems are visually—and gemologically—distinct from the production of other manufacturers.

Next, Tomasz Powolny and Dr. Magdalena Dumańska-Słowik reexamine spotted “dalmatian jasper,” a popular decorative gem material. Based on their analysis of its composition and gemological characteristics, which do not meet the definition of jasper, the authors recommend use of the term “dalmatian stone.”

In our final article, Darwin Fortaleché, chief gemologist at Centro de Desarrollo Tecnológico de la Esmeralda Colombiana (CDTEC), and his GIA coauthors provide a comprehensive field report on current mining and the state of the Colombian emerald industry. They cite increased investment by multinational companies, the country’s largely untapped emerald reserves, and the initiation of chain-of-custody systems as hopeful signs for the future.

Our Lab Notes section features an entry on a large, high-quality diamond from Brazilian kimberlite. Topics in our Micro-World section include hematite roses and a “flower-in-the-rain” inclusion within a Sri Lankan sapphire, while our Gem News International section spotlights blue-green pyrope-spessartine with high vanadium content and two potential new sources of Nigerian sapphire.

Please enjoy the Fall G&G! @chapter:35


Publication Year: 2013 Title: Colored Stones Cut with High Precision Abstract: Figure 1. Tiny but precisely cut and highly saturated stones were offered at Tucson. Photo by Eric Welch.

              At the AGTA and GJX shows, China Stone (Bangkok) marketed a selection of tiny, precisely cut natural gemstones. Sold as parcels, the stones ranged from 0.03 to 3.0 mm in diameter. Despite their small size, they were impressively saturated with a full spectrum of colors (figure 6).

The stones are natural and purchased directly from the source suppliers, then cut and polished in the company’s Chinese factories. With computer-controlled automation, the stones are digitally calibrated and precisely cut to be set into commercial jewelry. The company’s products include ruby, blue and fancy-color sapphire, amethyst, chrome tourmaline, and tsavorite. The matched stones can be used in graphic designs or as accent stones in fine jewelry.

Clients of China Stone’s high-precision cut stones include watch manufacturers, fine jewelers, and designers. The company developed its own inventory grading, stock management, and order processing systems to maintain the strictest standards of shape, size, color, and quality. For each type of gemstone, color grades are assigned with several different color codes. Customers can easily combine their favorite colors and sizes of a certain stone type and see whether the goods are in stock or need to be ordered. With the development of automated cutting technology, small rough can be easily handled and cut with very high precision, giving jewelry designers creative flexibility. @chapter:28


Publication Year: 2023 Title: More on Virtu Gem’s Ethical Supply Chain Practices Abstract: Figure 1. These indicolite tourmalines (9.27 and 6.16 ct) from Zambia are among the variety of gems Virtu Gem offers. Photo by Robert Weldon.
We first covered Virtu Gem at the 2023 Ethical Gem Fair in Tucson (see Spring 2023 GNI, pp. 122–125). Virtu Gem gives artisanal and small-scale miners, traders, and cutters in Kenya, Malawi, and Zambia formal access to the international market and offers training in cutting, basic gemology, and mine safety.
The gems Virtu Gem sells (see figure 1) are cut in the source country and tracked with Provenance Proof Blockchain. One of Virtu Gem’s efforts is training artisans in cutting and polishing standards to meet international market expectations. Percy Maleta, Virtu Gem’s country exporter and ambassador in Malawi, said the training has attracted many cutters there and allowed them to sell gems at premium prices.

Figure 2. Gemstone cutters in Kenya, Malawi, and Zambia developed cuts to represent their countries in Virtu Gem’s National Gem Cut Course. Left to right: the Kenya Cheetah Head, Zambia Eagle, and Malawi Mbuna Fish cuts in aquamarine, amethyst, and rhodolite garnet. Photo courtesy of Virtu Gem.
In 2022, Virtu Gem launched the National Gem Cut Course in the three countries. In online workshops led by Adriano Mol from the University of Minas Gerais State, cutters learned facet development and brainstormed to design gem cuts to represent their nations. The resulting cuts (figure 2) resembled a cheetah head for Kenya, the mbuna (cichlid) fish for Malawi, and the eagle for Zambia. Buyers can order gemstones from each country in its respective cut.
Virtu Gem has received two grants from the World Bank as well as assistance from other organizations. Rio Grande donated a GemLightbox, and Virtu Gem purchased more for its three country coordinators. The GemLightboxes allow traders to upload photos and videos of gems to the online sales platform rather than export stones on consignment. In addition, Gemworld donated its World of Color books to each country coordinator, which help traders evaluate color and cut and set prices.
The donations have also been instrumental in Virtu Gem’s work with the National Gem Cutting School in Zambia, where students use the books and GemLightboxes. Virtu Gem cofounder Susan Wheeler said there are many gem cutters in Kenya, and she would like to establish a gem cutting program for women in Malawi.
Wheeler said gemology students should understand the ethical issues inherent in the traditional gemstone supply chain and the importance of cutting in the source country. She emphasized the importance of knowing that prices are based on not only the gemstones but also the labor of the miner and the jewelry manufacturer and other costs.

Figure 3. Virtu Gem’s Kenya country coordinator, Caroline Muchira, with Nadan tsavorite mine manager Daniel Chege (left) and owner John Kimuyu (right). Photo courtesy of Virtu Gem.
Virtu Gem’s country coordinator for Kenya, Caroline Muchira (figure 3), is a gem cutter by trade. While working full-time in logistics, she was inspired to travel more than 300 km by bus every weekend from Nairobi to Voi to visit the mines and talk to traders. “I was fascinated by the gemstones and how the miners could tell the difference between green garnet, green tourmaline, and pieces of green glass,” Muchira said. She planned to study gemology in retirement, but in 2009, after the company she worked for was sold, she sold all of her belongings to earn her Graduate Gemologist diploma at GIA’s Thailand school. During Muchira’s visits to Voi, she saw the issues the miners faced, especially women and youth. “Often they are unable to sell their stones at a fair price to middlemen, whose aim is to strike the lowest possible deal, leaving miners barely able to eke out a living,” she said. Virtu Gem’s system focuses on fair pricing, and Muchira now runs the organization’s pricing workshops.
Muchira’s ability to earn a GG is not the norm. Maleta said many in Malawi’s gem trade are interested in taking GIA courses but can’t afford it. “In a country with more than 60,000 artisanal and small-scale miners, Malawi probably only has two or three GIA graduates,” he said.
The communities Virtu Gem works with produce a wide variety of gemstones, but they have yet to access some resources. While some artisanal and small-scale mining (ASM) of emeralds occurs in Zambia, Wheeler pointed out, the miners are largely unable to access the more than 400 ASM emerald concessions in Zambia, in the same area as Gemfields. Two women they work with in Zambia have a digger but can’t afford the fuel to run it. “They could be producing the same quality emerald as Gemfields,” Wheeler said. “They can’t afford to do it on a regular basis, and loans are very expensive. We want to support the emerald mining. So we’re trying to work on how to go forward with sourcing and getting more supply with emeralds.”
Virtu Gem is part of the United Nations Conscious Fashion and Lifestyle Network, which highlights collaborations that further the UN’s Sustainable Development Goals (SDGs). Virtu Gem’s efforts are associated with six of the SDGs: ending poverty, ending hunger, gender equality, decent work, inclusive and sustainable industrialization, and reducing inequality. “We’re going to continue to align everything that we do in Virtu Gem with the Sustainable Development Goals so people can see that framework and what gemstones can do to make progress,” Wheeler said. @chapter:38


Publication Year: 2019 Title: Dravite from Mozambique with an Abundance of Pyrite Inclusions Abstract: Figure 1. Six yellow to brownish yellow faceted dravite tourmalines (0.47–2.8 ct) from Mozambique, many of which contained distinct metallic inclusions of pyrite. Photo by Weizhi Huang.

In the summer of 2017, author JP encountered a parcel of transparent yellow to brownish yellow tourmalines at the gemstone market in Chanthaburi, Thailand. The six faceted tourmalines shown in figure 1 revealed properties consistent with tourmaline. LA-ICP-MS analysis was performed to determine their major chemical components, which were: 11.56–12.31% MgO, 9.98–10.34% B2O3, 2.62–2.82% Na2O, 0.68–1.06% CaO, 0.17–0.45% TiO2, and 0.11–0.25% FeO (total iron). Minor amounts of Li, K, V, Cr, Mn, Zn, Ga, and Sr were also detected, indicating dravite tourmaline.

Figure 2. The dravites contained distinctive inclusions of pyrite, which were confirmed by Raman spectrometry. Photomicrograph by Weizhi Huang; field of view 0.8 mm.
These dravites were noteworthy for their numerous euhedral pyrite crystal inclusions (figure 2), confirmed by Raman. This was previously reported without Raman analysis (see Spring 2007 GNI, pp. 73–75). This is the first time the authors have seen so many intact pyrite crystals in yellow to brownish yellow gem-quality dravite from Mozambique. @chapter:5


Publication Year: 2023 Title: GIA Alumni Collective Abstract: Akshay Poddar, Melizza and Jennifer Tanpoco, and Julia Hackman Chafé are some of GIA’s featured graduates on the Alumni Collective website.
Discover the GIA Alumni Collective, a networking and knowledge hub for GIA graduates. The online community at collective.gia.edu is a diverse group who all share a passion for the gem and jewelry industry. Users can access both live and self-paced Continuing Education seminars, join virtual chapters, connect with global alumni, and more. The site also highlights some of the GIA alums who uphold GIA’s highest standards (see above).
Akshay Poddar earned his Graduate Gemologist diploma at GIA’s Mumbai campus. A third-generation diamantaire, Poddar was driven to start his own business, dealing in both wholesale trade and retail. The diamond jewelry designer believes that while nature creates the diamond, his job is to add beauty to it.
Jennifer Tanpoco launched Jaune Pearls in 2002, later enlisting her daughter Melizza as CEO. The Tanpocos, both GIA Pearls Graduates, focus on sustainability and long-term environmental impact in their business, educating clients on how the pearls are sourced.
Julia Hackman Chafé used her marketing background and her Colored Stone Essentials Certificate from GIA to create a strong digital presence after taking over social media for her family’s wholesale colored stone business. Now a successful influencer under the name JewelsWithJules, Chafé shares photos and videos of gems, jewelry, and international travel, providing her followers with a unique look at the colored stone trade.
Visit https://collective.gia.edu/meet-the-collective.html to read stories from these alumni and more. @chapter:34


Publication Year: 2023 Title: Jewelry sales tend to expand during the Mother's Day to August (Shikago) festival season. Abstract: The article discusses the economic outlook and consumer behavior trends in the United States leading up to Mother's Day. Despite ongoing economic challenges such as inflation and a slowing job market, consumer spending during this holiday season is expected to remain robust. Retailers are gearing up with special promotions to attract consumers looking to purchase gifts to express their love and appreciation for mothers.
Key findings from the National Retail Federation's survey indicate that American consumers plan to spend approximately $4 billion more on Mother's Day gifts this year compared to the previous year. This increase reflects a growing trend in consumer sentiment towards spending on gifts. The most popular categories for gifts include jewelry, electronics, and clothing, with jewelry being the top-selling category.
Furthermore, the data highlights that consumers are increasingly interested in subscription boxes and experiential gifts as alternatives. There is also a significant emphasis on personalized and unique gifts that create special memories for recipients.
For Thai entrepreneurs and exporters, the Mother's Day season in the US presents a strategic opportunity to capitalize on these consumer trends. Key products such as jewelry, decorative items, and customized gifts tailored to the occasion are particularly sought after. The US remains a critical market for Thai exports in these categories, with potential for further growth, especially if products align with consumer preferences for vibrant colors and personalized items.
In conclusion, while economic conditions in the US remain uncertain, consumer spending for occasions like Mother's Day continues to drive economic activity. Thai businesses looking to export to the US should leverage these insights to develop and market products that appeal to American consumers during these festive seasons. @chapter:27


Publication Year: 2023 Title: Gübelin Gem Museum Opens in Switzerland Abstract: Figure 1. A look inside the new Gübelin Gem Museum in Lucerne, Switzerland. Photo courtesy of Gübelin.

Figure 2. A display case featuring emerald at the Gübelin Gem Museum. Photo courtesy of Gübelin.
In July 2023, the Swiss firm Gübelin, known for its luxury timepieces and jewelry and its gemological laboratory, opened the Gübelin Gem Museum in Lucerne, Switzerland (figure 1). The collection allows visitors to explore the formation, origin, and diverse colors of fascinating gemstones (figure 2), as well as the history of the family-owned business, founded in 1854.
The opening of the museum commemorates the 100th anniversary of the Gübelin Gem Lab, which became a world-renowned institution in the field under the leadership of Dr. Edward J. Gübelin. Recognized for his gemstone inclusion research, Dr. Gübelin’s groundbreaking work is a focal point of the museum, including many of his instruments and gemstones he collected during his travels worldwide. Visitors will discover 174 gemstones selected from the company’s reference collection in addition to selected Gübelin watches and jewelry pieces from various eras.
The compact space not only houses historical exhibits but also provides a window to the future. Visitors will learn about Provenance Proof, the company’s blockchain technology for colored gemstones, and Gemtelligence, a colored gemstone analytical tool that uses artificial intelligence to increase consistency in data interpretation, origin determination, and identification of heat treatment. It is also the new home of the Gübelin Academy, offering courses to inspire students in the museum setting. Through digital and interactive elements, the exhibits will be continuously updated and expanded, ensuring new experiences for years to come. For more information, visit www.gubelin-gemmology.com. @chapter:22


Publication Year: - Title: 2016 Hong Kong Show: Demand Slightly Up Abstract: Buyers convene for the diamond and gem portion of the Hong Kong Gem and Jewellery Show at Asia World Expo. The finished jewelry portion of the show is held at the Hong Kong Convention Centre in the central part of the city. Photo by Russell Shor/GIA

	Demand for diamonds and colored gems at the Sept. 13-19 Hong Kong Gem and Jewellery Fair exceeded the expectations of most exhibitors, even if some of the demand came from other dealers bargain hunting from their colleagues in need of cash. Most dealers reported an improvement from last year’s business.

	Chinese retailers and wholesalers believe consumer demand in China is starting to stabilize at a sustainable trading level after two years of market correction following a decade of double-digit growth. In diamonds less than a carat, demand centered on medium colors and clarities. Dealers reported a slight upturn in demand for better quality diamonds over three carats. Price was still a major issue with hard bargaining over relatively small differences, delaying a lot of deals.

	In colored stones, demand still focused on finer colors for ruby, emerald and sapphire, with continuing strong demand for popularly priced gems, such as amethyst and citrine.

	As with last year, the stronger dealers began the show by buying a lot of goods from colleagues in need of hard cash after finding their credit lines severely reduced or cut off entirely.

	As one major dealer noted, “In the past, there were sellers offering big discounts, which pushed down prices for everybody. If we buy them first, it helps us maintain prices.”

	Paspaley Pearling Company held its annual tender auction of South Sea white cultured pearls and golden cultured pearls from the Philippines on the final two days of the Hong Kong show. Demand for both varieties remained similar to last year, an executive from the company said.

	Dealers from around the world inspect lots of South Sea and golden cultured pearls at the Paspaley pearl auction held in conjunction with the Hong Kong Gem and Jewellery Show. Photo by Russell Shor/GIA

	DIAMONDS

	Demand at De Beers’ Aug. 29-Sept. 2 sight (cycle) was strong, according to the company. The $630 million total includes all sales – tender auctions, side deals (called “ex-plan”) and sight sales. De Beers made no announcement about prices, which means they remained steady.

	This sight is the last of the year in which the rough diamonds can be polished in time to reach key U.S. and Asian markets in time for the end-of-year holidays.

	The total is considerably higher than July’s cycle of $528 million; the final three sales of the year likely will show strong increases over last year’s numbers when the market was in extreme turmoil and many clients were refusing goods.

	Alrosa, the world’s largest diamond producer by volume, reported that its first half sales totaled 21.7 million carats, a 21% increase over 2015. Its revenues were up 46% over the same period.

	In a surprise announcement, Rio Tinto bailed out of the Bunder diamond project in Madya Pradesh, India. The final stages of sampling were complete and estimates indicated that it would yield about 27.4 million carats over its lifetime from a cluster of eight kimberlite pipes. Rio Tinto built a highly automated recovery plant to process the samples, along with ore from the mine, after start-up.

	Rio Tinto’s then-CEO Sam Walsh called on India’s Prime Minister Narendra Modi in 2013 to help expedite the approvals process for the project. As late as July of this year the company was issuing optimistic reports that it would begin production in 2019, but later in the month Jean-Sebastien Jacques replaced Walsh as CEO. The company announced it would sell Bunder as a cost-cutting move in August.

	A report in Bloomberg said that several large companies have cancelled development plans in India because of costly, drawn out approval processes and land acquisition procedures.

	This was the second major diamond project to be scuttled this year. De Beers closed Snap Lake in northern Canada earlier in the year because it had become unprofitable. The company is still seeking a buyer.

	Signet Group, the parent company of Kay Jewelers, Jared Galleria and Zales, reported that its second quarter same-store sales were down 2.3% from the same period last year. For Kay Jewelers, the average transaction price fell by 0.8%, but rose slightly for the Zale division, which generally trades at a lower market segment. A statement from chairman Mark Light noted that sales were particularly depressed in “energy-dependent” areas of the U.S., referring to regions where oil and gas production is a significant part of the economy. In addition, stagnant wages and a general malaise in the national mood have dampened demand for luxury goods.

	Tiffany & Co. saw its second quarter same store sales fall by 9% worldwide. Declines were steep in every major market: 8% in North America; 6% in Asia-Pacific; and 17% in Europe. The company cited “well-known” economic factors for its sales decline, as well as a steep decline in Chinese tourism that has had a worldwide impact on the company’s revenues. @chapter:30


Publication Year: - Title: Designer’s Love of Brazil – and its Gems – Shines in Every Piece She Creates Abstract: Karyna Sena loves the travel involved in her gem and jewelry career and has visited mines in Brazil and other countries since she was a young girl. “Tell me that you need me to go somewhere in the world,” she says, “and all I need to do is check the temperature to pack.” She is pictured at a sapphire mine near Colombo, Sri Lanka. Courtesy of Karyna Sena

	The rich tapestry of Brazil − from its dances, music and Carnival festivals to its native plants, animals and fruits − finds its way into each piece of designer Karyna Sena’s jewelry.

	“I try to explore the Brazilian ‘way’ in my pieces,” says Sena, a GIA GG born in Salvador, capital of the gemstone-rich state of Bahia. “Jewelry must be fun!”

	Sena’s joie de vivre, and her enthusiasm for her homeland, reflects a career and life that have, in one way or another, intersected with almost the entire colored stone supply chain of Brazil.

	“As the granddaughter of a miner and daughter of a gem dealer, colored gemstones run in my blood,” says Sena, whose father opened a wholesale and retail store, Lasbonfim, in 1967. Sena had a playpen in the store and grew up “crawling the floors of the family store.” She remembers finding rough colored stones mixed up with her dolls, and taking trips to mines with her family.

	“I remember clearly the first time my parents took us to an emerald mine in Campo Formoso, in the countryside of Bahia,” she says. “I was the first one to jump in the hole – never afraid of the dark or high temperature. I felt like Indiana Jones looking for treasures!”

 Karyna Sena as a child, left, with her mother, father and two younger brothers, at a Lasbonfim store opening and ribbon-cutting ceremony in the 1980s. “As the granddaughter of a miner and the daughter of a gem dealer, colored gemstones run in my blood,” Sena says. Courtesy of Karyna Sena

	Sena was also captivated by her father’s ability to discern an emerald’s origin by analyzing its colors and inclusions. He taught her how to classify the rough and polished stones and made sure she knew the ins and outs of the family business.

	“My parents gave us the best education possible and let us choose whatever we wanted to do as a career, but they made sure that we knew our business,” she says. “If we didn’t succeed in whatever career we had chosen, we would always know how to do something else.”

	But Sena was “completely in love with Brazilian gemstones” and wanted the family business as her “life’s work.”

	She earned bachelor’s degrees in the late 1990s in both geology and business from the Universidade Federal da Bahia and Universidade Salvador, respectively, then moved to Europe to “experience the glamour and trends of the European fashion industry firsthand, and be exposed to a diversity of styles.” She made London her home base and traveled throughout the continent (and many others) for several years.

	She returned to Brazil in 2012 to design and market her own jewelry line at Lasbonfim. “Back in the ‘80s, everything available at my parents’ store was very classic,” she says. “I decided to make jewelry with ‘odd’ cuts and with gemstones that were not usually set in jewelry in 18K gold.”

	Sena’s “dreams in the form of jewelry” were inspired by “the colors and the happiness of Brazil, meeting the elegance of Europe.” Her first line, Orishas, sold well – and quickly, particularly to North American tourists wanting to take home a piece of Brazil.

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	She incorporated her design line, Karyna Sena, but even with her success as a designer and as the director of Lasbonfim, she felt like she was missing something – a GIA diploma. She knew about GIA because her parents often helped GIA instructors and gemologists who came to Brazil to teach or do business.

	“They would trade gems for gem-testing equipment that we couldn’t find in Brazil,” she says. “I had a chance to meet some of these people and learn the importance of the work that GIA does,” she says.

	“I learned a bit of theory by studying geology and lots of experience in the trade, but I wanted the international respect that a GIA gemologist has. I wanted that diploma on my wall.”

	Sena moved back to London to study at the Institute’s campus there, and earned her Graduate Gemologist and AJP diplomas in 2011.

	“It was a sabbatical year, entirely devoted to GIA. I always joke that I was married to GIA for that time,” she says. “You have to have passion for it. It is only with focus, commitment and passion that you can succeed. It is a hard course, but it completely pays off.”

	Along with the “incredible networking opportunities,” Sena appreciates that she uses what she learned at GIA “on a daily basis” – especially as she also does valuations now.

 Karyna Sena holds several leadership positions in the gem and jewelry industry, including serving as the vice president of the CIBJO retail sector. She is pictured here at a 2015 event, with (from left) Fiera di Vicenza President Facco Corrado, CIBJO President Gaetano Cavalieri and GJEPC Vice Chairman Pankaj Parekh. Photo by Paulo Alcantara /Courtesy of Karyna Sena

	In addition to her many roles at Lasbonfim and Karyna Sena, she is serving as the first female president of the Bahia Association of Producers and Traders of Gems, Jewelry, and Precious Metals; is the youngest board member of the Brazilian Institute of Gems and Precious Metals; and is the vice president for the retail sector of the CIBJO World Jewelry Confederation.

	“We are living in a very competitive and professional world – it is smaller and faster, and there is no room for amateurism anymore,” says Sena, who lives in Brazil with her husband, Marcelo Storel. “I truly believe that the only way to be successful and still be in the game is by being creative and professional. And you can only achieve this with education.” @chapter:34


Publication Year: - Title: Conference Report: 11th Annual Sinkankas Symposium Abstract: Robert Weldon discusses ruby photography at the 2013 Sinkankas Symposium in Carlsbad, California on April 6. Photo by Tao Hsu.

                      The 2013 Sinkankas Symposium was held April 6 at GIA’s world headquarters in Carlsbad, California. The annual symposium honoring John Sinkankas was organized by the San Diego Mineral & Gem Society (SDMG) and GIA. Ruby was the theme of the conference, which drew more than 150 attendees.

Following convener Roger Merk’s opening remarks, Dr. George Harlow, curator of earth and planetary sciences at the American Museum of Natural History in New York, gave the first presentation of the day. “The Mineralogy and Geochemistry of Ruby from the Mogok Belt” discussed the geology and trace-element origin indicators of these gems. Dr. Harlow also pointed out that gemological journals should publish full data sets rather than data summaries. Dr. James Shigley, GIA’s distinguished research fellow, summarized the conditions and environments of ruby formation and reviewed the major localities worldwide. Bill Larson of Pala International gave a virtual tour of the world’s important localities and showed outstanding rough samples. Elise Skalwold of Cornell University shared the life story of Dr. Allen M. Bassett, who spent some 30 years in Nepal studying its geology and developing an integrated jewelry industry there. Next, explorer and author Gary Bowersox presented “The Rubies of Afghanistan and Tajikistan,” which featured numerous maps and photos based on more than 40 years of experience traveling in this area. In “Pigeon’s Blood: Burma’s Mogok Ruby Mines,” Richard W. Hughes related the history of operations there and clarified the real meaning of the term “pigeon’s blood,” which is derived not from the blood of pigeons but from the bright red ring in the iris of their eyes.

Nathan Renfro, GIA Carlsbad’s lead analytical specialist of colored stones, explained how to use computer-aided techniques plus spectra-aided color prediction to optimize the face-up color of faceted rubies. Mr. Renfro also shared some fascinating photomicrographs of rare inclusions in rubies. Robert Weldon, GIA’s manager of photography and laboratory publications, reviewed the history of ruby photography and gave the attendees three simple tips on correcting the gem’s color using Adobe Photoshop. GIA’s West Coast identification services director, Shane McClure, concluded the day with a review of ruby treatment techniques such as heating, dyeing, fracture filling, and lattice diffusion. Cal Tech’s Dr. George Rossman was scheduled to be the last speaker of the day but could not attend. Mr. Merk gave a brief summary of Dr. Rossman’s presentation “Why Rubies Are Red” to close the event. @chapter:3


Publication Year: 2002 Title: Winter 2002 Gem News International Abstract: Diamonds
            Kimberley Process Ratified
Colored Stones and Organic Materials
            Alexandrite from Mananjary, Madagascar
            Color-Change Apatite from Kazakhstan
            New Emerald Find from the Chivor Region, Colombia
            Important Discovery of Jadeite in Guatemala
            Faceted Milarite with Unusual Inclusions
            Spinel Crystal with an Unusual Shape
            More Tourmaline from Warner Springs, California
            Faceted Rossmanite and other Tourmalines from Nigeria
            Uvite Tourmaline from Afghanistan
Synthetics and Simulants
            An Assembled Agate “Nodule”
            A Glowing Manufactured Gem
            “Rainbow Calsilica”
            Heat Treatment Experiments on Faceted Amber
            An Update on Be-Diffused Corundum
            Orange Topaz with Synthetic Hematite Coating
Conference Reports
            Diamond Presentations at the Annual Australian Diamond Conference
            Antwerp Diamond Conference
            Antwerp Gem Conference
Announcements
            Beryllium: A Known Carcinogen
Conferences
            PDAC 2003 Will Take Place in Toronto in March
            Basel 2003 Scheduled for April
            Moscow Gemology Colloquium Takes Place in Moscow in April
            Gems and Industrial Minerals Conference Will Occur in Reno in May
            GAC-MAC-SEG Meeting Set for Vancouver in May
            Maine Pegmatite Workshop Included in Field Studies
            Kimberlite Conference Planned in Victoria in June
In Memoriam
            Prof. Dr. Pieter C. Zwaan, 1928–2002, Gems & Gemology author and noted gemologist

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


Publication Year: - Title: Spring 2009 G&G Lab Notes Abstract: Cubic Zirconia Reportedly Coated with Nanocrystalline Synthetic Diamond
Diamond with Assemblages of K-Feldspar, Hematite-Magnetite, and Quartz in Etch Channels
Clarity Grading Radiation Stains in Diamond
Rare Mixed Type (Ia/IIb) Diamond with Nitrogen and Boron Centers
Purplish Pink Spinel from Tajikistan—Before and After Cutting

To view the full section, download the PDF above. @chapter:11


Publication Year: 2021 Title: Two Antique Mughal Spectacles with Gemstone Lenses Abstract: Figure 1. These antique spectacles contain diamond (left) and emerald (right). Photos by Jian Xin (Jae) Liao.
Lenses play a major role in the daily work of a gemologist, from magnification using a loupe or microscope to the optics used in conjunction with lasers from advanced testing instruments. Even our eyes contain organic lenses, which we use to see the world. In many cultures, seeing the world in completely new ways is often achievable by means of introspection such as contemplative moments or meditation, but sometimes all one truly requires is a pair of glasses.
Recently, GIA’s New York laboratory had the spectacular opportunity to observe and analyze two pairs of truly unique antique spectacles (figure 1). The two spectacles have a storied connection dating back to the height of the Mughal Empire. Their lenses are crafted from diamond and emerald, respectively. According to information provided by the client and independent researchers, the two pairs of spectacles were likely fashioned in mid-seventeenth century India, a period in the Mughal Empire that had an established lapidary tradition and artisans with the expertise to accomplish such creations. Information submitted by the client suggests that the lenses may have been cut from the same rough diamond and the same rough emerald, respectively. Further evidence suggests that while the fashioning of the lenses dates back to the seventeenth century, the frames date from the late nineteenth century based on design and style.

Figure 2. Left: Overlapping mid-infrared spectra of both lenses revealed them to be type Ia diamonds. Right: Two strain images, one of each lens, under cross-polarized light showing natural growth structure and internal stress during natural diamond formation. Images by Christopher Vendrell; field of view 19.27 mm.
The first of the two spectacles, called Halqeh-Ye Nur or “Halo of Light,” consists of two transparent near-colorless modified pear-shaped lenses in a yellow metal frame surrounded by numerous transparent near-colorless stones of various shapes and cuts. The client requested that only the two near-colorless transparent lenses be tested. Infrared spectra and strain images were collected as part of the testing (figure 2). Both lenses were identified as natural type Ia diamonds, sharing matching spectra when overlapped. The strain images revealed natural growth structures and internal stress during diamond formation. While GIA’s investigations were limited in scope to identifying the gem material set in each pair of spectacles, the evidence as a whole seems to suggest that the lenses were cleaved from the same large diamond rough.
The second pair of spectacles, called Astaneh-Ye Ferdaws or “Gate of Paradise,” consists of two transparent green pear-shaped lenses in a white and yellow metal frame set with two green rectangular step cuts and numerous near-colorless stones of various shapes and cuts. According to information provided by the client, the pear-shaped lenses originate from a single natural emerald that originally weighed more than 300 carats. Both spectacles are consistent with the design and style of the late nineteenth century and are believed to have been upgraded to the fashion of the time.

Figure 3. A field of jagged three-phase inclusions hosting gas bubbles, colorless cubic crystals, and aqueous liquid. Photomicrograph by Augusto Castillo; field of view 1.99 mm.
The client requested that both green transparent lenses as well as all 45 of the surrounding near-colorless stones be tested. Microscopic observation, one of the main identification methods for emeralds, revealed an inclusion scene typical for emeralds from Colombia: classic jagged three-phase inclusions hosting a gas bubble and a cubic colorless crystal suspended in fluid (figure 3). It is well established that these daughter crystals are halides, commonly rock salt, derived from the saline brine contained in the primary fluid inclusion (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Vol. 3, 2008, Opinio-Verlag Publishers, Basel, Switzerland, p. 427).

Figure 4. Opaque black grains were also observed, consistent with inclusions observed in emeralds from Colombia. Photomicrograph by Augusto Castillo; field of view 1.26 mm.
Unidentified tiny opaque black grains were also observed (figure 4), but otherwise the lenses were relatively inclusion free. Examination of minor fissures seen near the gem’s surface using ultraviolet light and microscopic observation indicated the presence of an oil or resin, but this is not believed to have affected the overall appearance. Therefore, the emeralds were classified as having “no indications of clarity enhancement.”
Standard gemological testing revealed a refractive index of 1.577 to 1.583 with a birefringence of 0.006. Examination between crossed polarizing filters showed a uniaxial optic figure. The pleochroism was green to blue-green, and a handheld spectroscope revealed a typical emerald spectrum. These properties and observations confirmed that the green transparent lenses were natural emeralds.
All 45 of the transparent near-colorless stones surrounding the two emerald lenses were identified as diamonds using GIA’s iD100 device, microscopic observation, and additional advanced testing.
Even by today’s standards, these astonishing curiosities are objects of technical mastery by the artisans and the brilliant vision of the patrons who commissioned the spectacles. From these fine examples of Mughal craftsmanship, to more modern examples such as synthetic sapphire sunglasses made for Sir Elton John (see Winter 1997 Lab Notes, p. 296), we continue to be pleasantly surprised by gem materials passing through GIA that have been fashioned into unique items such as these lenses. We imagine Sir Elton would approve of these Mughal spectacles. @chapter:24


Publication Year: 2016 Title: Afghan Emerald, Tajik Ruby, and Clarity-Enhanced Tourmaline Abstract: Figure 1. Left: Eternity Natural Emerald offered precision-cut Afghan emeralds, including “star” (left), princess (center), and baguette cuts (right, ranging from 6 × 3 mm to 5 × 2 mm). Photos by Robert Weldon/GIA, courtesy of Eternity Natural Emerald.

	Eternity Natural Emerald (Ridgewood, New Jersey) exhibited a number of fascinating stones at the AGTA show. The emerald melee from Afghanistan (figure 1) immediately caught our attention. One of the authors was present in Afghanistan when Eternity’s Arthur Groom examined the original material (called “pencil rough” for its long and thin shape). The color was retained even when cut into small stones.

	This rough is typically not treated, but a consistent supply of Afghan emerald is difficult to obtain. Prices are high, and negotiating is complex. Security concerns make it difficult to move rough in the country, and material is often smuggled to Dubai for the international market. To purchase the material, the company makes four to six buying trips a year, with permanent buyers located in Kabul and the Panjshir Valley. Much of the rough consists of the pencil crystals used for cutting precision melee. Once the pencil rough is sawn and preformed, the stones are cut for maximum brightness and the tightest measurement tolerances possible. All melee is cut in Sri Lanka.

	The emeralds were displayed in a variety of cuts and sizes. Most of the production is between 2 and 4 mm; they try to cut the melee within 0.05 mm tolerance. Mr. Groom expects to unveil 10,000–15,000 carats at the 2016 JCK show in Las Vegas. Eternity Emerald is also purchasing rough from Zambia and Brazil to ensure a continuous supply of melee.

	We also saw a 12.52 ct cushion-cut emerald (figure 2) that came from a 60 ct Afghan rough. The stone was difficult to cut because the rough was highly fractured and color zoned. Also from the 15,000-carat parcel purchased this year were four stones that did not require enhancement, the largest of which weighed 4.61 ct. Mr. Groom estimated that, given the same size and quality, the value difference between treated and untreated emerald ranges from 20% to 100%.

Figure 2. This 12.52 ct cushion-cut Afghan emerald came from a highly fractured and color-zoned 60 ct rough. Photo by Robert Weldon/GIA; courtesy of Eternity Natural Emerald.

	Also on display was a 17.14 ct ruby that had the intense red color of marble-hosted material and a slightly sleepy transparency. The untreated ruby was cut from a 45.37 ct rough, part of a parcel of more than 1,000 carats, purchased directly from Tajik miners in May 2015. While this rough is available within Tajikistan, Mr. Groom said the material is not easily found on the global market. The asking prices for the rough were high and firm. The parcel was much more difficult to evaluate than ruby from Myanmar or Mozambique, as the rough was highly fractured. This is not uncommon for Tajik ruby, and it makes determining the yield and quality of the finished stones problematic. Due to the fracturing of the rough, heat treatment may not be a viable option for color improvement. The parcel yielded a total of nine faceted stones, none of which were heat treated. The largest, a 21.17 ct stone, was cut from the original 45.37 ct rough. A large black inclusion was still visible after cutting. After being shown to several potential buyers, the ruby was recut to 17.14 ct. The inclusion was less visible in the resulting gem (figure 3), and the color and brightness were also improved. Mr. Groom said recutting increased the ruby’s overall value more than 30%.

Figure 3. The decision to recut a 21.17 ct ruby into this 17.14 ct gem added substantial value. Photo by Robert Weldon/GIA; courtesy of Eternity Natural Emerald.

	At the booth, we also saw photos of their clarity-enhanced tourmalines. Clarity Enhancement Laboratories (CEL) performs the filling of the surface-reaching fractures. Mr. Groom pointed out that fracture filling of tourmaline is nothing new. Most of the material he has seen in the market has been filled with oils and resins, often without disclosure, since the trade has not traditionally thought of fracture filling as a way to improve tourmaline’s apparent clarity. In August 2015, CEL announced tourmaline clarity enhancement service. The process, which is similar to its ExCel method for filling emerald fractures, is offered in their New York City laboratory for all colors and varieties of finished tourmaline. This treatment is not available for rough material.

Figure 4. The surface-breaking fissure in this faceted Paraíba tourmaline (left) is less visible after cleaning and filling (right). Photos courtesy of Eternity Natural Emerald.

Figure 5. Prior to treatment, the highly visible fissure detracted from the rubellite’s clarity (left). After treatment, the fissures were less visible, and the stone had a more uniform clarity (right). Photos courtesy of Eternity Natural Emerald.

	Although they will fill any variety and color of tourmaline, CEL has mostly received Paraíba (figure 4), rubellite (figure 5), and bicolor material. Mr. Groom attributes this to the intrinsically higher values for these varieties. These color varieties often have surface-reaching fractures, and the filling process makes the material much more marketable. Since there is a high demand for these types of tourmaline, treated goods are still of value to dealers. Mr. Groom hopes to promote CEL’s clarity enhancement method as a positive thing that will be fully disclosed through the value chain. @chapter:7


Publication Year: - Title: Aquamarine History and Lore Abstract: The Dom Pedro aquamarine obelisk by gem sculptor Bernd Munsteiner is the largest cut aquamarine. - Eric Welch, courtesy Smithsonian Institution

                      The name “aquamarine” is derived from two Latin words: aqua, meaning “water,” and marina, meaning “of the sea.”

It has been said that the mineral beryl gives the wearer protection against foes in battle or litigation. It makes the wearer unconquerable and amiable, and also quickens the intellect.

Aquamarine is the birthstone for March. @chapter:2


Publication Year: 1997 Title: Synthetic Moissanite: A New Diamond Substitute Abstract: A new diamond imitation, synthetic moissanite (silicon carbide), is now being produced by C3 Inc. in near-colorless form for jewelry purposes. With refractive indices of 2.648 and 2.691, a dispersion of 0.104, a hardness of 9¼ on the Mohs scale, and a specific gravity of 3.22, synthetic moissanite is much closer to diamond in overall appearance and heft than any previous diamond imitation. The thermal properties of synthetic moissanite are also so close to those of diamond that the thermal probes currently on the market react to synthetic moissanite as if it were “diamond.” This new material can be readily separated from diamond on the basis of its anisotropic optical character, which produces a doubling in the appearance of facet junctions. A new instrument manufactured by C3 Inc. solely to distinguish synthetic moissanite from diamond was also examined for this study. @chapter:32


Publication Year: - Title: Jadeite Jade Quality Factors Abstract: Jadeite comes in a wide range of colors. The most valuable is an intense green called Imperial. - Courtesy Mason-Kay Fine Jade Jewelry

                      To understand the value of jade, you have to look beyond its durability and its role as a gemstone and beautiful adornment. Jade is a spiritual stone with significant meaning that’s intricately woven into the Chinese culture.

The price for fine-quality jadeite has risen dramatically along with China’s economic rise. The demand from those who can newly afford it has significantly outpaced the supply of this rare material.

The Chinese have revered jadeite’s fine green color since its discovery in Burma. Top-quality jadeite is rare. Vivid, sleek, and translucent, magnificent jadeite commands some of the highest prices among gems in today’s international market.

Jadeite’s three most important qualities, in order of their impact on its market value, are color, transparency, and texture.

When jadeite buyers evaluate fashioned jadeite, they consider many factors. First, they judge its color under both fluorescent and incandescent light sources. They check its level of transparency. They look for even coloration or a pleasing mottling of colors. They also look for fine polish and undistorted surface reflections. Clarity is important, too, because any fractures can strongly affect value.

Color
Color is jadeite’s most important value factor. Because consumers traditionally associate jadeite with the color green, it surprises some people to learn that it comes in other colors as well—lavender, red, orange, yellow, brown, white, black, and gray. All of these colors can be attractive. But jadeite’s most desirable color is, in fact, a very specific shade of green.

	Jadeite jade comes in a variety of colors. Green is the most valuable. - Courtesy Mason-Kay Fine Jade Jewelry
The finest-quality jadeite—almost transparent with a vibrant emerald-green color—is known as “Imperial jade.” The royal court of China once had a standing order for all available material of this kind, and it’s one of the world’s most expensive gems.

The green that can command millions of dollars in the marketplace is pure and penetrating, a vivid hue with no hint of gray that looks intense even from a distance. It ranges from pure green to a slightly bluish green or a slightly yellowish green.

Other highly valued jade varieties include “kingfisher jade,” with a green color that’s only slightly less vivid than Imperial; “apple jade,” which is an intense yellowish green; and “moss-in-snow jade,” which is translucent white with bright green veining, patches, or spots. The most outstanding examples of these are almost always bought and sold in the Asian market.

Lavender is the next most valuable color. Intense colors command a substantial premium over lighter and weaker colors. Black jade is also popular, along with orange to reddish jade, especially when these colors are not brownish.

Transparency
Jadeite’s transparency ranges from completely opaque to semitransparent. The best jadeite is semitransparent, meaning the text you can read through it would be slightly blurred. Because light penetrates below the surface, semitransparent jadeite has an alluring brilliance. It almost appears to glow, increasing the charm of a lush green or rich lavender hue. The least desirable jadeites are completely opaque or have opaque or cloudy patches that break up their transparency.

	Some jadeite is transparent enough to allow the observer to see into the stone, revealing the gem’s depth of color and giving it higher value. - Gift of Sophie Leu
To judge transparency, some buyers place a thin jadeite slice on a printed page and try to read the print through the gem. If the transparency is excellent, the viewer can see the print easily, even if the jadeite is dark green. Good transparency can sometimes compensate for lack of uniform color or low color saturation.

Texture
Jadeite has a smooth, even texture that makes people want to touch and hold it. Jadeite’s texture can be fine, medium, or coarse, depending on variations in crystal size and hardness. These texture categories are sometimes called, respectively, old mine, relatively old mine, and new mine.

	When jadeite’s structure is fine-grained, the gem has smooth texture and high luster. - Courtesy Mason-Kay Fine Jade Jewelry
The same crystal structure that contributes to jadeite’s texture also contributes to its exceptional toughness. Jadeite’s interlocking crystals, also called grains, produce a tightly inter-grown, compact mass that bonds together and resists breaking. In the early days of its history, when it was used to fashion tools and weapons, jadeite’s ability to withstand breakage was one of its major advantages.

Cut
China is the world’s main polishing center for jadeite. Some jadeite from Myanmar is fashioned near its source, in cutting workshops near the open jade markets of Hpakan, Lonkin, Mogaung, and Mandalay. Many cutters there still polish jadeite the ancient way, using a hollow bamboo lathe treated with sand and water.

Manufacturers fashion jadeite into a handful of distinctive, traditional jewelry forms. Some are hololiths, carved entirely from a single piece of rough. Hololiths include bangles, rings, and pendants.

	Cabochons of various shapes, bangle bracelets, and round or carved beads are the most common jadeite jewelry styles. The deep, even, green color of this cabochon is far from common, however. - Gift of Sophie Leu
The finest-quality jadeite is usually cut into cabochons for use in rings and other jewelry. When buyers judge cabochons, they consider symmetry, proportion, and thickness. Calibration is not as important for top-quality material as it is for more commercial qualities. The finest jadeite cabochons are rarely cut to calibrated sizes because the cutter’s goal is to save rough weight.

Fine-quality jadeite might also be cut into round beads, which are carefully selected and strung into strands. Color and texture are the most important factors for matching jadeite beads. Manufacturers also match transparency, size, and symmetry of cut. Because matching is difficult, especially for color, longer strands or larger beads can sell for extremely high prices.

The jade bangle, first carved in China from nephrite, is a style thought to date back at least four thousand years. A smooth circle of bright jadeite wrapping the wrist is thought, even today, to bring peace and protection to its wearer. Jadeite bangles can be highly important pieces of jewelry.

Some bangles are hololiths. When a cutter fashions a bangle from a single piece of rough, a great deal of weight loss results. For this reason, hololith bangles cost more than bangles that consist of several pieces joined together by precious-metal hinges.

The Chinese eternity symbol, or bi, bears great spiritual significance for many jadeite connoisseurs. The shape is simple: a convex or plump disk with a round hole in its center. Ideally, the jadeite should be more than twice as wide as the hole.

Jadeite rings are often simple all-jadeite bands. The finest bands show uniform color all the way around. A variation on this is the saddle ring, a solid band with a carved rectangular-shaped top.

Size and Weight
Jadeite size is commonly expressed in millimeters. The value of cabochons, beads, and bangle bracelets rises with an increase in size, all other quality factors being equal. With top-quality imperial jadeite, slight differences in size can make large differences in value. With nephrite, larger sizes do not raise the value dramatically in most cases.

	Jadeite is available in a wide range of sizes for jewelry as well as carvings. - Gift of Sophie Leu @chapter:37


Publication Year: - Title: Fall 2016 G&G: CVD Synthetic Diamonds Survey, Reversible Color Change in Blue Zircon Abstract: Nathan Renfro’s article in this issue describes how exposing blue zircon to long-wave UV radiation causes them to turn brown, and how this color modification can be reversed. The 7.95 ct blue zircon ring on the cover is set in 18K white gold and surrounded by 2.43 carats of rubies. It is shown alongside a similar ring with a 5.46 ct tanzanite center stone. Both were designed by Loretta Castoro of Los Angeles for her KissMe collection. Photo by Kevin Schumacher, courtesy of Loretta Castoro.

	CVD-grown diamonds, colored stones, and Indonesian cultured pearls are featured in the latest Gems & Gemology. The Fall 2016 issue reviews the characteristics of several hundred CVD synthetic diamonds; describes how long-wave UV radiation can turn blue zircon brown; and examines the properties of Vietnamese peridot, grandidierite from Madagascar, and Russian alluvial sapphire. The issue also includes a field report from a trip to a cultured pearl farm on the Indonesian island of Lombok.

	OBSERVATIONS ON CVD-GROWN SYNTHETIC DIAMONDS: A REVIEW

	Since 2003, GIA has examined hundreds of gem-quality CVD synthetic diamonds. As growth technology becomes more advanced, the size and quality of these synthetics continue to increase. In the lead article, Sally Eaton-Magaña and James Shigley survey several hundred, CVD samples, interpreting grading factors and analytical data to gain greater insight into indicators of CVD origin.

The lead article of the Fall 2016 issue reviews the characteristics reported from several hundred CVD synthetic diamonds examined by GIA over the past 13 years. These near-colorless and Fancy Vivid purplish pink samples are representative of most of the CVD-grown samples seen at GIA labs. Photo by Robert Weldon/GIA.

	REVERSIBLE COLOR MODIFICATION OF BLUE ZIRCON BY LONG-WAVE ULTRAVIOLET RADIATION

	After learning from gem dealers that blue zircons had turned brown after exposure to long-wave UV radiation, Nathan Renfro undertook a study to see if the blue color could be restored by exposure to incandescent light. Spectroscopic analyses pinpointed the features responsible for the color modification.

	The 11 faceted blue zircons of unknown origin seen on the left all showed a brown face-up color after several minutes of long-wave UV exposure. Photo by C.D. Mengason.

	SAPPHIRES FROM THE SUTARA PLACER IN THE RUSSIAN FAR EAST

	With only one placer deposit of gem-quality sapphire, Russia has long relied on sapphire from other parts of the world. But the Sutara River region of Russia’s Jewish Autonomous District is another potential source of corundum. A team of researchers led by Svetlana Buravleva uncovered sapphire at the deposit and studied the chemical composition and gemological properties of the cabochon-grade material.

	This silver pendant contains a 65.5 ct sapphire cabochon from Sutara, in the Russian
	Far East. Photo by Svetlana Buravleva, courtesy of A. Kurnosov.

	A NEW DEPOSIT OF GEM-QUALITY GRANDIDIERITE IN MADAGASCAR

	A deposit of grandidierite outside Tranomaro, Madagascar, has yielded bluish green to greenish blue crystals that are among the purest known examples of this material. Delphine Bruyère and her coauthors examined samples from the new source, recording its gemological properties, collecting chemical composition data, and discussing the material’s market potential.

This 0.11 ct round brilliant grandidierite from Madagascar has no eye-visible flaws. Photo by Delphine Bruyere.

	PERIDOT FROM THE CENTRAL HIGHLANDS OF VIETNAM

	Recognizing the importance of Vietnamese peridot to the global gem industry, Nguyen Thi Minh Thuyet and colleagues established the geological and P-T formation of the material, concluding that it derives from a spinel lherzolite source. They also compared the gemological characteristics and geochemical data of peridot from the Central Highlands to specimens from other known localities.

The light yellowish green 5.09 ct peridot in this gold ring is from Vietnam’s Bien Ho deposit. Photo by Nguyen Thi Minh Thuyet.

	BEAD-CULTURED AND NON-BEAD-CULTURED PEARLS FROM LOMBOK, INDONESIA

	In this field report, Nicholas Sturman and his coauthors recount their visit to a pearl hatchery in Lombok, Indonesia. There they observed the daily activities of a pearl farm and collected bead-cultured and non-bead-cultured pearls from P. maxima mollusks for further study and future identification purposes.

A group of bead-cultured pearls of various hues recovered from hatchery-bred Pinctada maxima oysters at Lombok, Indonesia. Photo by Julie Poli.

	LAB NOTES

	Highlights from the Fall Lab Notes section include reports on the capabilities of GIA’s melee sorting service, a sapphire rough filled with green lead glass, a treated pink diamond colored by red luminescence, and a purple fluorite inclusion in emerald.

	MICRO-WORLD

G&G’s photomicrography section includes entries on unusual growth zoning in Pakistani aquamarine, etch features in spinel from Madagascar, and a mobile fluorite inclusion within quartz.

	GEM NEWS INTERNATIONAL

	The Fall 2016 GNI section provides updates on Tanzanian colored gemstone deposits, “Punsiri”-type spectral features in natural yellow sapphire, and use of the DiamondView instrument to identify impregnated jadeite. @chapter:11


Publication Year: 2017 Title: Vesuvianite in Burmese Ruby Abstract: This vibrant yellowish green crystal in a faceted ruby from Myanmar was identified as vesuvianite. Photomicrograph by Nathan Renfro; field of view 1.20 mm.

It is a pleasant surprise when a gemologist encounters a vibrantly colored crystal in a gemstone, as most gems are either inclusion free or contain inclusions that are weakly colored due to their small size. When the authors discovered a vibrant yellowish green crystal in a Burmese ruby (see above), it was a very welcome sight. Green crystals in corundum are not common but do occur occasionally. Green spinel and pargasite both occur in gem corundum. The former, a singly refractive mineral, was ruled out immediately because this inclusion behaved as a doubly refractive mineral when examined between crossed polarizers. Doubly refractive pargasite remained a possibility. The surprise came when Raman microspectrometry identified the yellowish green crystal as vesuvianite, also known as idocrase. To the authors’ knowledge, this is the first time vesuvianite has been reported as an inclusion in ruby. @chapter:4