# Publication Year: 2017
# Title: Cape Diamond with Yellow Phosphorescence
# Abstract: Figure 1. This yellow-green 0.75 ct cape diamond displayed yellow phosphorescence to long-wave UV light. Photo by Sood Oil (Judy) Chia.

	Phosphorescence in a cape diamond is very rare, especially after exposure to long-wave UV light. The New York laboratory recently examined a cape diamond exhibiting yellow phosphorescence after exposure to a long-wave UV source. The 0.75 ct Faint yellow-green round brilliant is shown in figure 1.

	Cape absorption peaks were observed at 415 and 477 nm, along with a GR1 peak (figure 2, left). The IR spectrum confirmed that this was a type Ia diamond, with nitrogen aggregates detected in the one-phonon region. Hydrogen-related peaks were also detected at 1405, 2785, 3107, 3237, 4169, and 4496 cm–1. Brown radiation stains were found on the girdle. The diamond contained contacted partially graphitized omphacite crystals with cuboctahedral morphology (figure 2, right). Strong blue fluorescence and medium yellow phosphorescence were observed under a desktop long-wave UV light source. Under short-wave UV, medium yellow fluorescence was noted but phosphorescence was absent. DiamondView imaging (<225 nm excitation) also showed greenish blue fluorescence but no phosphorescence. Fiber-optic illumination revealed the blue “transmission” luminescence that occurs when a strong light travels through a diamond. The UV-Vis spectrum of such diamonds shows an absorption peak at 415 nm and a luminescence peak at the lower energy end of the peak. Such is the case with this stone.

	Figure 2. The diamond displayed “cape” absorption peaks at 415 and 477 nm along with a GR1 peak (left). It contained contact crystal inclusions of green omphacite (right; field of view 1.41 mm). Photo by Kyaw Soe Moe.

	Nearly 30 years ago, a bicolor diamond with a near-colorless central portion and light yellow tips was reported in G&G (Winter 1989 Lab Notes, p. 237). It showed very weak chalky yellow phosphorescence for approximately 10 seconds after the long-wave UV lamp was turned off. This yellow phosphorescence was observed throughout the stone regardless of its bicolor nature. Its central colorless region exhibited weak cape lines and strong blue transmission, similar to the green diamond in this note. Unlike our sample, the bicolor diamond also showed very weak yellow phosphorescence to short-wave UV. A chameleon diamond may display strong yellow phosphorescence to a long-wave UV light source (Summer 1992 Lab Notes, p. 124; Spring 2000 Lab Notes, pp. 60–61). Our sample was not a chameleon diamond, however.

	Greenish yellow phosphorescence in a chameleon diamond has been systematically measured using a spectrometer (see S. Eaton-Magaña et al., “Fluorescence spectra of colored diamonds using a rapid, mobile spectrometer,” Winter 2007 G&G, pp. 332–351). The peak maximum recorded for the chameleon diamond was 557 nm. We used an Ocean Optics USB2000 charge-coupled device (CCD) spectrometer similar to the one described in Eaton-Magaña et al. (2007), but with a different UV source. In place of a deuterium source, we used GIA’s new LED desktop long-wave UV (365 nm excitation) light source. A broad peak at approximately 570 nm, which is responsible for the yellow phosphorescence, was observed in the emission spectra (figure 3, left). The phosphorescence decay curve at 570 nm, representing the rate of decreasing intensity with time, is plotted in figure 3 (right). Half-life is defined as the time required for the initial peak intensity to decrease to one-half its original value (again, see Eaton-Magaña et al., 2007). The half-life value measured for our sample was 5.0 seconds.

	Figure 3. Phosphorescence spectra (left) show a peak maximum at 570 nm, which is responsible for the cape diamond’s yellow phosphorescence. Shown on the right is the phosphorescence decay curve at 570 nm.

	Yellow phosphorescence is a very rare feature in cape diamonds. The defect responsible for this optical feature remains unknown. @chapter:22 @chapter:1 @chapter:22


# Publication Year: 2014
# Title: Round CVD Synthetic Diamond Over 1 Ct Identified in Hong Kong Lab
# Abstract: Figure 1. Left: This 1.20 ct CVD synthetic round brilliant had a color grade of L, a clarity grade of SI2, and a cut grade of Very Good. Right: The 6.7 mm specimen contained a few black inclusions with irregular shapes. Photos by Ping Yu Poon.

In the past ten years, CVD synthetic diamonds have showed significant improvements in quality and size (Martineau et al., Spring 2004 G&G, pp. 2–25; Wang et al., Winter 2003 G&G, pp. 268–283; Wang et al., Summer 2012 G&G, pp. 80–97). Their color and clarity can be comparable with top natural counterparts, but for the most part they are still small. CVD gem-quality synthetic diamonds over 1 ct are occasionally reported in the trade, usually in fancy shapes with limited depth.

Recently, a round-brilliant specimen, identified as a CVD synthetic diamond, was submitted to the Hong Kong laboratory for grading service. It weighed 1.20 ct (6.70 × 6.72 × 4.30 mm), with a color grade of L, a clarity grade of SI2, and a cut grade of Very Good. This specimen resembled well-cut natural round diamonds (figure 1, left), with a few black inclusions of irregular shape clearly observable under the microscope (figure 1, right).

Figure 2. The CVD synthetic diamond’s infrared absorption spectrum showed a weak peak at 1344 cm–1. This feature, attributed to the isolated nitrogen impurity, was responsible for the L color grade.
Infrared absorption spectroscopy identified it as type IIa. A very weak absorption at 1344 cm–1 was attributed to isolated nitrogen in the diamond lattice (figure 2). Based on the absorption intensity (0.014 cm–1) of this peak, the total concentration of isolated nitrogen was well below 1 ppm. Occurrence of trace isolated nitrogen was the major optical center responsible for the L color observed. No hydrogen-related absorption was observed at either 3107 or 3123 cm–1 using infrared absorption spectroscopy. Photoluminescence (PL) spectra at liquid nitrogen temperature with 532 nm laser excitation showed the [Si-V]– doublet emissions at 736.6 and 736.9 nm (figure 3), a characteristic feature of CVD synthetic diamond. Weak emissions from N-V centers at 575.0 nm and 637.0 nm were also recorded. Fluorescence images collected using the DiamondView showed green fluorescence with characteristic CVD growth striations (figure 4). All these gemological and spectroscopic observations, very similar to those of Gemesis specimens (Wang et al., 2012), confirmed this was a CVD synthetic diamond. It was annealed at high pressure and high temperature (HPHT) to improve its color appearance.

Figure 3. A photoluminescence spectrum collected at liquid nitrogen temperature using 532 nm laser excitation revealed a strong emission doublet at 735.6 and 735.9 nm, indicating a [Si-V]– optical center.

Figure 4. Observed in the DiamondView, the 6.7 mm synthetic diamond showed typical striations indicative of CVD growth. Image by Carmen Lo.
As this sample shows, CVD technology has reached a new milestone, with the growth of crystals thick enough to consistently cut well-proportioned round brilliants. It is highly likely that we will see more gem-quality CVD synthetic diamonds over 1 ct in the trade. @chapter:9 @chapter:1 @chapter:9


# Publication Year: 2016
# Title: Update on Spectroscopy of “Gold Sheen” Sapphires
# Abstract: Figure 1. These 14 sapphires, weighing up to 97.69 ct each, displayed a golden sheen effect and in some cases six-rayed asterism. They possessed sufficiently large inclusion-free areas to enable good-quality spectra.

Sapphires displaying a golden sheen, known in the trade as “gold sheen” or “Zawadi” sapphires, entered the gem market in late 2009. These sapphires are mined in eastern Kenya (T.N. Bui et al., “From exsolution to ‘gold sheen’: A new variety of corundum,” Journal of Gemmology, Vol. 34, No. 8, 2015, pp. 678–691). They contain dense needles and platelets of hematite/ilmenite inclusions, which are responsible for producing a golden shimmer on the surface.

Recently, GIA’s laboratory in Bangkok received 14 gold sheen sapphires of various shapes and cuts. The samples had yellow and green to blue bodycolor, were transparent to translucent, and weighed 1.06 to 97.69 ct (figure 1). Their physical properties and inclusions were similar to those of gold sheen sapphires described in Bui et al. (2015): an RI of 1.762–1.772, a birefringence of 0.008–0.009, a hydrostatic SG of 3.98–4.01, an inert reaction to long- and short-wave UV radiation, and an abundance of hematite/ilmenite platelets. Since the samples had some transparent windows, UV-Vis-NIR spectra were analyzed.

The UV-Vis-NIR spectra all displayed strong Fe-related absorption features at 377, 388, and 450 nm. Samples with a yellow bodycolor showed mainly the three Fe features, whereas the green to blue sapphires revealed a band centered at around 580 nm that is related to Fe2+-Ti4+ intervalence charge transfer, in addition to the three strong Fe features (figure 2). LA-ICP-MS analysis on inclusion-free areas showed high Fe ranging from 2550 to 3260 ppma, 2 to 8 ppma Mg, 4 to 11 ppma Ti, 30 to 45 ppma Ga, and 0.2 to 0.7 ppma V. For the green to blue samples, Ga/Mg overlapped, varying from 5 to 30. Samples with a yellow bodycolor varied from 4 to 11. Other trace elements including Zr, Nb, Ta, W, Th, and U were also detected but in insignificant quantities. It is notable that Mg and Ti concentrations were comparable in the yellow samples (all Ti4+ charges compensate Mg2+, leaving no Ti4+ to interact with Fe2+), whereas Ti concentrations were significantly higher than Mg concentrations in the green to blue sapphires resulting in some Ti4+ forming Fe2+-Ti4+ pairs (J.L. Emmett et al., “Beryllium diffusion of ruby and sapphire,” Summer 2003 G&G, pp. 84–135). The chemical and UV-Vis-NIR spectroscopic features corresponded with the bodycolors of these sapphires. In addition, FTIR spectra of the gold sheen sapphires generally showed diagnostic features of AlO(OH), consistent with either boehmite or diaspore; kaolinite; and gibbsite.

Figure 2. The UV-Vis-NIR spectrum of a gold sheen sapphire with yellow bodycolor
revealed strong Fe-related absorption features at 377, 388, and 450 nm. The spectra
of green to blue samples revealed an additional Fe2+- Ti4+ intervalence charge-transfer
band centered at around 580 nm. These samples were not specifically aligned to the
c-axis. @chapter:24 @chapter:0 @chapter:24


# Publication Year: 1999
# Title: Garnets from Madagascar with a Color Change of Blue-Green to Purple
# Abstract: Gemological, chemical, spectroscopic, and microscopic properties of blue-green color-change garnets from a new deposit near Bekily, Madagascar, are given. The samples are members of the pyrope-spessartine solid-solution series, with smaller constituents of almandine and grossular. The alexandrite-like color change from blue-green in daylight to purple in incandescent light is mainly caused by relatively high amounts of vanadium (about 1 wt. % V2O3). These garnets are particularly noteworthy because they represent the first commercially available “blue” garnets. @chapter:12 @chapter:0 @chapter:12


# Publication Year: -
# Title: Emerald History and Lore
# Abstract: The 75.47-carat Hooker Emerald was worn by Ottoman Sultan Abdul Hamid II, the last sultan of the Ottoman Empire. Photo by Chip Clark, courtesy Smithsonian Institution, National Museum of Natural History.

                      Emerald’s lush green has soothed souls and excited imaginations since antiquity. Its name comes from the ancient Greek word for green, “smaragdus.” Rome’s Pliny the Elder described emerald in his Natural History, published in the first century AD: “…nothing greens greener” was his verdict. He described the use of emerald by early lapidaries, who “have no better method of restoring their eyes than by looking at the emerald, its soft, green color comforting and removing their weariness and lassitude.” Even today, the color green is known to relieve stress and eye strain.

There are other green gems, like tourmaline and peridot, but emerald is the one that’s always associated with the lushest landscapes and the richest greens. Ireland is the Emerald Isle. Seattle, in the US state of Washington, is the Emerald City. Thailand’s most sacred religious icon is called the Emerald Buddha, even though it’s carved from green jadeite.

The first known emerald mines were in Egypt, dating from at least 330 BC into the 1700s. Cleopatra was known to have a passion for emerald, and used it in her royal adornments.

Emeralds from what is now Colombia were part of the plunder when sixteenth-century Spanish explorers invaded the New World. The Incas had already been using emeralds in their jewelry and religious ceremonies for 500 years. The Spanish, who treasured gold and silver far more than gems, traded emeralds for precious metals. Their trades opened the eyes of European and Asian royalty to emerald’s majesty.

Emerald is the most famous member of the beryl family. Legends endowed the wearer with the ability to foresee the future when emerald was placed under the tongue, as well as to reveal truth and be protected against evil spells. Emerald was once also believed to cure diseases like cholera and malaria. Wearing an emerald was believed to reveal the truth or falseness of a lover’s oath as well as make one an eloquent speaker.

Legend also states that emerald was one of the four precious stones given by God to King Solomon. These four stones were said to have endowed the king with power over all creation.

Its color reflects new spring growth, which makes it the perfect choice of a birthstone for the month of May. It’s also the gemstone for twentieth and thirty-fifth wedding anniversaries. @chapter:40 @chapter:2 @chapter:40


# Publication Year: 2023
# Title: Misfit Diamonds: Beauty in the Imperfect
# Abstract: Figure 1. Alex Skachkov of Misfit Diamonds. Photo by Jennifer Stone-Sundberg.
At the AGTA show, we spoke with Alex Skachkov of Misfit Diamonds (Vancouver, Canada) about some of their unusual diamonds (figure 1). When asked what was popular, he showed us their aptly named “salt and pepper” diamonds (see also figure 5 of the Tucson 2023 overview), which contained eye-visible black and white inclusions. These had a very distinct look and were cut into various nonstandard shapes (figure 2).

Figure 2. “Salt and pepper” diamonds. Left to right: a 4.30 ct hexagonal step cut, a 5.56 ct octagonal step cut, a 3.58 natural-color orange cushion cut, and a 3.39 ct pear cut. Photo by Robert Weldon; courtesy of Misfit Diamonds.

Figure 3. Nontraditional diamond cuts and slices in a range of sizes. Photo by Jennifer Stone-Sundberg; courtesy of Misfit Diamonds.
Skachkov described the appeal of these unique and beautiful “imperfect” diamonds, particularly to younger designers and consumers. In his words, younger customers are not necessarily interested in absolutely flawless gems. Rather, many are looking for gems that charm in their distinctive and rare “perfect imperfection.” He noted that these diamonds are also a more budget-friendly option. In addition to the “salt and pepper” diamonds, we got a close look at diamonds and sapphires cut into nontraditional shapes, including slices (figure 3).
Skachkov mentioned that many of their customers now look for full disclosure of the entire mine-to-market custody chain. Misfit Diamonds provides this information whenever possible, though at times their diamonds arrive in mixed-origin parcels, with stones from a variety of global locations. Moving forward, they aim to meet the challenge of reporting full chain of custody, as they predict increasing demand for this feature. @chapter:50 @chapter:3 @chapter:50


# Publication Year: 2018
# Title: Book Review: Rings
# Abstract: By Rachel Church, 160 pp., illus., publ. by Thames & Hudson, London, UK, 2017, US$24.95.

Rings by Rachel Church is a well-curated overview of ring history based on the jewelry collection in the Victoria and Albert Museum. Though short, the book is packed with information.
Six chapters move through time from the Middle Ages, when jewelers were unsung and unremembered craftsmen, to the present, when individual jewelers are known and the work of name designers is sought after and collected.
Church writes, “to study rings is to study a miniature history of art and design.” However, each chapter outlines the successively shorter time periods it has taken for culture and society and jewelry design to change. The rings in each section reflect shifts in wedding and betrothal practices, religious beliefs and superstitions, memorial practices, and fashion. Rings denoting particular affiliations—with the church, royalty, and political loyalties—show how sources of power have shifted over centuries.
Chapter One: 1200–1500 explores rings during the Middle Ages, when gifts of rings affirmed the power and status of the giver and rewarded the loyalty and services of the recipient. Rings set with fine gemstones were the prerogative of the clergy, royalty, and the aristocracy. Incised or engraved gems from the ancient world as well as intaglios from the time of the Romans were also revered and set into rings.
As a gift of love, a ring was one of the types of gifts a woman was allowed to properly receive from a lover. Rings could provide talismanic protection when, as they commonly were, engraved with prayers or invocations against illness, accident and evil.
This was the time that magical lore and many beliefs about gemstones came into common knowledge, the result of translating the works of ancient lapidaries. However, not only precious gemstones, but homely materials became valued for their prophylactic properties. Witness the image of a spectacular ring with heavy engraved shank that is set with heart-shaped wolf’s tooth to protect against toothache and inscribed with an invocation against storms. A toadstone, actually the fossilized tooth of a prehistoric fish, was worn as an amulet against spider bites and other venoms.
Chapter Two: 1500–1700 shows that, during the Renaissance, rings were still used for personal protection and prayers but became more decorative and showy, with highly carved and enameled bezels and shoulders. Multi-part, interlocking “gimmel” rings became more prevalent and were sometimes used as wedding rings—the separate but joined rings reflecting the state of marriage. “Posy”—from poesie or poetry—rings also date from this time. These gifts of love, betrothal, and marriage were engraved with short romantic lines. They were so popular that for the unimaginative there were even compendiums of phrases from which to choose one’s verse.
The growing importance of secular, more material society was reflected in the increased presence of signet rings—plain or gemstone set—engraved with a family crest or merchant’s symbol. Extraordinary gold rings, such as the one set with an exceptional emerald and diamonds that is believed to have been given by King James II to his chaplain, were still used to cement loyalty between royalty and those who served them well.
During the Middle Ages, memento mori rings were intended to remind the wearer of the brevity of life with their macabre skulls and other symbols of deaths. However, during the Renaissance, there was a subtle shift away from emphasis on one’s own mortality to the memorialization of someone else’s passing. The rings were usually inscribed with the name of the deceased and their date of death, and they could be very simple or beautifully enameled remembrances. Simple rings were often given to mourners.
The introduction of the new rose cut caused many women to have their diamonds recut and reset into fashionable designs often derived from flowers. Enameled designs might be based on the work of French floral artists. Center stones might be surrounded by smaller stones imitating the petals of a flower.
Chapter Three: 1700–1820 covers the period defined by Rococo and Neoclassical design. During this time, the fashion for floral-based rings grew and became more complex. There was a passion for giardinetti, or “little garden” rings created by setting colored stones into intricate patterns forming baskets and vases of flowers. Diamond rings became a necessary accessory for any gentleman.
Memorial rings, as bequests to friends and gifts to mourners, became so popular that they were a staple of jewelers who “advertised their ability to make mourning rings neatly and expeditiously.” Large mourning rings would often exhibit painted miniatures, hair under crystal, and enameled images. Not only friends and family were memorialized, but political leaders and military heroes, too, were commemorated. Church has included an image of the illustrated memorial ring made in remembrance of Admiral Horatio Nelson, who died at the Battle of Trafalgar (1805).
As society became increasingly secularized, rings symbolizing an affiliation with political party rather than with royalty or aristocracy or church proliferated. Membership in clubs, social, and fraternal organizations, such as the freemasons, was also marked with the wearing of rings that incorporated their emblems.
One interesting societal and legal change impacted the importance of the ring in marriage. Before the mid-1700s, the “lawful basis for a marriage was simply the exchange of vows in the present tense by the two parties, and a wedding could take place at any time of day.” Often the legitimacy of a marriage was determined by the gift of the ring. However, this could result in the kidnapping of a woman—particularly an heiress—who was forced into an unwanted marriage, and perhaps had a ring forced on her legitimizing the union. The Marriage Act of 1753, however, required that weddings take place in an Anglican church, during the day, and only after the publication of the banns. This meant that while rings were still part of the service, the real proof of the marriage lay in the church register and in the testimony of witnesses.
Chapter 4: 1820–1900 describes changes brought about by the Romantic movement, when artists looked to the past as idealized eras. Design ideas from the Middle Ages and the Renaissance were reinterpreted, as well as those from the Rococo and Neoclassical periods. In rings, loving sentiments were spelled out with gemstones, with each letter of a word represented by the first letter of the name of the stone. For those with a longer message to deliver, there was enamel. The book shows a particularly delightful gold ring with small doors that open to reveal sections of a message much like the “She loves me, she loves me not” of a plucked circle of daisy petals. In this case, each door hides “I love you a little/a lot/ passionately/not at all.” A subtler message of eternal love was delivered by an emerald ring in the shape of a snake, given by Prince Albert to Queen Victoria on their engagement.
“Romantic” though this period was, it was also practical. Although the value in a wedding ring is primarily in its sentiment, in 1855, Parliament required that all wedding rings bear hallmarks.
Chapter 5: 1900–1950, raises the curtain on the twentieth century and the dawn of the “Me” and “Look at Me” generations. Gone are rings of power, magic, affiliation, and mourning. The demand for fashion rings, started in the previous century, outstripped just about all other roles except for wedding and engagement. It is during this time that the major jewelry houses emerged.
The Art Nouveau and Art Deco movements led this explosion of design that emphasized originality above almost all else. These designs were often characterized by the use of “semi- precious” stones such as opals, moonstones, and unusual stones such as amber, jadeite, and chalcedony. Art Deco in particular incorporated modern materials such as plastics.
The use of less expensive materials became pronounced as the Great Depression took hold everywhere, and the trend was to “create an atmosphere of luxury with inexpensive materials that everyone can afford.” But with the return of luxury after World War II, gemstones took center stage as never before as film and stage stars began to wear large faceted gemstones such as citrines, aquamarines, and star stones both on the screen and off.
Chapter 6: 1950–Present brings the reader speeding into the art and studio jewelry world, as jewelry makers began to emphasize metalwork in their designs. Large rings, either unset or set with gemstones took over the hand. They began to look more like small sculptures than jewelry. Designers used unusual combinations of gemstones and materials. One image that demonstrates this dramatically is Bernhard Schobinger’s “Uhrfragment.” The ring is made from “braided metal wire” and a jeweled watch movement that looks as if it has been heated with a torch and burned. The rough, blackened textures contrast sharply with the single, luminous round pearl set in the center. This is not a ring anyone would have seen in any previous age.
Individual designers stepped out and became as well known as the celebrities they dressed. Galleries exhibiting studio jewelry opened their doors. The value in a ring might still be intrinsic to the materials used—gold and precious gemstones—but more often the value became attached to the art involved or to the designer’s name. Color, once provided by gemstones and enamel, began to be replaced with acrylics. In short, the only rule in the twentieth century was that just about anything goes.
Such a reference depends on the number, choice, and quality of the images, as well as the pieces selected. In Rings, the quality of both is exceptionally high. Hand-engraved pieces from 800 years ago look as if they were done yesterday. Full-page images allow examination of the smallest detail. In addition, there are paintings and photos of how rings have been worn and by whom in each era. There are also fascinating pages from old design books and jewelers’ ledgers that record finished drawings of pieces next to a coded breakdown of the labor and material costs.
The Notes section is fascinating, showing how far afield the study of jewelry can take you, with references to Old Bailey Proceedings, the study of wills, and personal histories as well as titles such as Mistress, Maids and Men: Baronial Life in the Thirteenth Century and At Home in Renaissance Italy. There is an interview with Dame Edith Sitwell. Even Jane Austen’s Northanger Abbey and John Donne’s poetry serve as sources. In addition, there is a glossary, suggestions for further reading, a brief history of the V&A’s collection, and a short list of other major collections featuring rings.
Rings is an excellent resource for antiques researchers or anyone interested in the story of jewelry in human history. As such, it is a wonderful companion to Cycles of Life: Rings from the Benjamin Zucker Family Collection. @chapter:25 @chapter:2 @chapter:25


# Publication Year: 2003
# Title: Obtaining U.S. Copyright Registration for the Elara Square Cut-Cornered Brilliant Diamond
# Abstract: In 2000, the U.S. Copyright Office granted what is believed to be the first copyright registration covering a gemstone design. Previously, the Copyright Office maintained that cut designs lacked artistic or sculptural authorship, and that gemstone faceting was a non-copyrightable array of common geometrical shapes in a three-dimensional object. The application to obtain copyright registration for the Elara—a square cut-cornered brilliant diamond design—was initially rejected on similar grounds. However, the position of the copyright examiner was successfully appealed to the highest level of the Copyright Office, which ultimately decided that copyright registration for the Elara cut was appropriate. This experience shows that there may be a new intellectual property vehicle available for manufacturers to protect proprietary cut designs. @chapter:33 @chapter:2 @chapter:33


# Publication Year: 1984
# Title: Pyrope-Spessartine Garnets with Unusual Color Behavior
# Abstract: The study of garnets by GIA’s Department of Research continues with a collection of 32 garnets that display a variety of hues and yet share a common tendency to show different colors under different sources of light. Even when very slight, the change of color is invariably greater than that encountered in other types of garnets. These unusual garnets proved to be composed principally of a variable mixture of pyrope (25-60 wt. %) and spessartine (20-56 wt. %) with considerable almandine (2-17 wt. %) and grossular (3-23 wt. %) also present. Their primary chemical distinction lies in their V2O3+Cr2O3 content, which is always in excess of 0.2 wt. %. In conjunction with their distinctive color behavior, these garnets may also be characterized on the basis of specific gravity and absorption spectrum. @chapter:13 @chapter:0 @chapter:13


# Publication Year: -
# Title: Books: Jewels by JAR
# Abstract: Essay by Adrian Sassoon, 144 pp., illus., publ. by the Metropolitan Museum of Art, distributed by Yale University Press, New Haven and London 2013, US$40.00. The JAR butterfly brooch (1994) is from a private collection. Photograph by Katharina Faerber, courtesy of JAR, Paris.

                      Joel Arthur Rosenthal is not a household name. Yet to many in the jewelry industry, the designs he creates for his jewelry house, JAR, are legendary for their innovation and artful use of color. Established in 1978, JAR is synonymous with quality and style. Alongside business partner Pierre Jeannet, Rosenthal has built a firm whose reputation is rooted in beauty, discretion, attention to detail, and deeply personalized service. Jewels by JAR was created to accompany the retrospective of the same name at the Metropolitan Museum of Art in New York City.

The book opens with a dedication by Rosenthal himself, with a foreword by Thomas P. Campbell, director of the Metropolitan. The main text is an engrossing essay by art dealer Adrian Sassoon on Rosenthal’s career. The essay will be particularly interesting to followers of the notoriously publicity-shy Rosenthal.

The remainder of the book consists of page after page of fabulous color images depicting handcrafted JAR creations. While one finds copious amounts of luxurious gems, gold, and platinum in his jewelry, Rosenthal has never limited his creations to so-called precious materials. Materials such as beetle wings, wood, resin, enamel, bronze, and aluminum have been used to complete his artistic vision. The success he has achieved is obvious in each photograph, deepening this reader’s lament that she did not have the opportunity to view the exhibit in person.

Even the pieces’ presentation boxes do not escape the discriminating eye of the designer. The interior of a given box might be custom-lined with suede of a color meant to complement the jewel it will hold. Box lids are often embossed with the owner’s initials, serving as a reminder that each JAR creation is indeed one-of-a-kind.

Truly lovely to look at, with an interesting text, Jewels by JAR is a “must-read,” not only for serious collectors of Rosenthal’s work, but for anyone interested in jewelry and jewelry design. @chapter:25 @chapter:2 @chapter:25


# Publication Year: -
# Title: Clam Chowder with a Side of Pearl
# Abstract: This white and purple pearl was found by restaurant staff while shucking clams for New England clam chowder. It formed in a northern quahog clam (sample shell shown). Photo: Sood Oil (Judy) Chia/GIA

Recently, GIA’s laboratory in New York had the opportunity to examine a fascinating find and hear about an even more fascinating story.

According to Bryan Gosman, co-owner of Gosman’s Fish Market in Montauk, Long Island, one of his staff was shucking clams in the kitchen while preparing to cook New England chowder when he discovered a pearl the size of a gumball.

“It didn’t look real,” said Gosman. “Usually [pearls are] the size of your pinky nail or something like that, but this looked like a plastic knob.”

He then reached out to Rebekah Harris – a co-owner of The Shipwreck Jewelry and Trading Company – to help him confirm the identity of the pearl. She assured him that the pearl was genuine and also the largest one she’d ever seen outside of a museum. She helped him submit the pearl to GIA in New York.

The quahog pearl was submitted to GIA’s New York laboratory for a GIA Pearl Identification Report. Photo: Sood Oil (Judy) Chia/GIA
GIA scientists confirmed that the pearl formed in a Mercenaria mercenaria (northern quahog) “clam.” It weighed 27.78 carats and measured 18.96 x 11.32 mm. To put that in perspective, many cultured pearls in jewelry stores range from 8-12 millimeters, meaning that this natural pearl is extraordinarily large. It is also a near perfect button shape, with an attractive white and purple color. Unlike many pearls valued for jewelry, it is non-nacreous, meaning its surface structure is different and has a more porcelaneous appearance.

Quahog ("koh-hawg") clams like the one that produced this pearl are found on the Eastern shore of North America, especially along the coast of the New England states, and can also be found along California’s Pacific coast. The pearls range in color from white and light gray to varied shades of purple, with purer colors being the most sought-after. Finding a quahog pearl is uncommon, not least because cleaning and shucking clams is often done mechanically, so most pearls are lost or destroyed in the process. The rare few pearls that make it into an unsuspecting patron’s food have been cooked, which can damage them. How fortunate that this pearl was discovered early and remained intact!

“What is it really worth? I don't know," Gosman said of the pearl. "It's not about the money – it's just kind of cool."

Gosman reported that he intends to raffle off the pearl to raise money for the Montauk Food Pantry.

The circumference of this button-shaped pearl is slightly larger than that of a dime. Photo: Sood Oil (Judy) Chia/GIA @chapter:53 @chapter:4 @chapter:53


# Publication Year: 1986
# Title: Colombage-Ara Scheelite
# Abstract: A new deposit of scheelite was discovered in 1983 near Ratnapura, Sri Lanka. This article analyzes the gemological properties of this rare gem mineral, and compares them with those recorded for scheelites from Mexico and the United States. @chapter:14 @chapter:0 @chapter:14


# Publication Year: 2013
# Title: “Gran Dama” Brooch Featuring Large Melo Pearl
# Abstract: Designed by Gianmaria Buccellati, the “Gran Dama” brooch celebrates pregnancy through its centerpiece 98.67 ct Melo pearl. Photo by Orasa Weldon.

              After a surge in popularity during the 19th century, Melo pearls reemerged on the gem market in the 1990s. These exceedingly rare pearls are produced by the Indian volute, a sea snail indigenous to Southeast Asia. The pearls themselves are non-nacreous and found in shades of orange, yellow, gray, and brown. Upon acquiring a 98.67 ct Melo pearl, thought to be one of the largest in the world, acclaimed jewelry designer Gianmaria Buccellati created the “Gran Dama” brooch to showcase this exceptional gem.

Created to honor the power of pregnancy, the brooch epitomizes, in Buccellati’s own words, “the highest and purest, I dare say divine, human state.” While many years were invested in the concept design and inspiration, the brooch itself required three years to complete, from original design to finished piece. The Melo pearl, representing the womb of the expectant mother, is accentuated by its setting in yellow, pink, and white gold, surrounded by 410 round brilliant diamonds and 139 fancy-color diamonds. The pear-shaped, 18.21 ct South Sea cultured pearl used for the brooch’s head provides a striking visual contrast with the orange, spherical pearl at the centerpiece of this work of art. @chapter:56 @chapter:2 @chapter:56


# Publication Year: 2018
# Title: Opal with Agate-Like Banding
# Abstract: Figure 1. This opal from the Shewa region of Ethiopia, weighing just over 10 ct, shows areas of agate-like banding. Photo by Diego Sanchez and Robison McMurtry.

Recently, author SC purchased an interesting Ethiopian opal (figure 1) that displayed a most unusual growth structure. A portion of the orangy brown opal displayed a small patch of wavy “varve” banding much like one would expect to see in an agate (figure 2). The banded area was composed of layers of translucent dark brown material alternating with lighter opaque material. It was also evident that the dark layers were much harder than the lighter layers, which had significant undercutting on the polished surface. These lighter areas also showed play-of-color, which made it obvious that they were precious opal layers. The dark areas did not show play-of–color, leaving it unknown if they were also opal or perhaps chalcedony, consistent with their banded pattern. It was also interesting to note that the lighter areas readily absorbed water and became transparent, an indication of hydrophane opal.

Figure 2. Prominent agate-like banding was seen in the opal. Photomicrograph by Nathan Renfro; field of view 8.22 mm.To test the composition of the various layers, we polished a flat surface on the back of the stone in order to accurately measure the refractive index (RI). Two measurements were resolvable with the refractometer, at 1.43 and 1.47. Further testing revealed an extremely low specific gravity measurement of 1.42 (compared to a typical SG of about 2.00 for opal), implying that the hydrophane areas were very porous. Further testing by Raman spectrometry was unable to detect the presence of quartz in either the light or dark brown bands, a finding consistent with the RI measurements.

Figure 3. Left: A crack running diagonally across the banding exhibits an offset shifting indicative of a strike-slip type of “micro-fault.“ Right: A second area in this stone also shows “micro-faulting“ with movement along the banding and no movement across the photonic crystal, indicating that opalization of the chalcedony was a secondary process. Photomicrographs by Diego Sanchez and Robison McMurtry; fields of view 2.50 mm (left) and 2.62 mm (right).
Careful microscopic observation yielded some interesting conclusions. A few small healed cracks in this stone were naturally repaired with opal infilling. Some of these cracks showed a lateral offset as they cut across the banding (figure 3, left). We also observed that the fractures that showed an offset in the banding showed no offset in the “photonic crystal” (B. Rondeau et al., “On the origin of digit patterns in gem opal” Fall 2013 G&G, pp. 138–146), or in the single play-of-color patches (figure 3, right). These observations are important in revealing the order of events that took place to produce such a specimen. First, the deposition of chalcedony had to occur in order to produce the crenulated (wavy) banded pattern. Second, stress cracks were introduced into the agate and then laterally shifted, creating several “micro-faults.” These micro-faults were subsequently “healed” with a secondary deposit of opal. This secondary opal deposition also replaced the chalcedony while preserving the original agate-like banding, which was apparent since there was no offset along the micro-faults in the patches of play-of-color.

This is one of the most unusual opals the authors have encountered to date. The microscopic observations tell an interesting story about the formation of a unique gem. @chapter:48 @chapter:0 @chapter:48


# Publication Year: 2003
# Title: An Important Exhibition of Seven Rare Gem Diamonds
# Abstract: From late June to mid-September 2003, seven important gem diamonds went on temporary public display at the Smithsonian Institution in Washington, DC, in an exhibit titled “The Splendor of Diamonds.” These diamonds, one colorless and six colored, are some of the rarest in the world: the 203.04 ct D-color De Beers Millennium Star, the 101.29 ct Fancy Vivid yellow Allnatt, the 59.60 ct Fancy Vivid pink Steinmetz Pink, the 27.64 ct Fancy Vivid blue Heart of Eternity, the 5.54 ct Fancy Vivid orange Pumpkin, the 5.51 ct Fancy Deep blue-green Ocean Dream, and the 5.11 ct Fancy red Moussaieff Red. This article provides background information on these spectacular diamonds and a record of some of the gemological observations obtained during their quality grading by GIA. @chapter:41 @chapter:1 @chapter:41


# Publication Year: -
# Title: Winter 2021 G&G Available Now
# Abstract: The Winter issue presents two characterization studies on gems from Mogok. These feature articles use Burmese blue sapphire and peridot of known provenance to enhance the current gemological knowledge base for origin separation. The third article combs through the early mining history of the Habachtal emerald deposit in Austria up to the beginning of World War I.
Blue Sapphires from Mogok, Myanmar: A Gemological Review
The lead article by Wasura Soonthorntantikul and co-authors investigates 248 blue sapphires collected from different areas in the Mogok Stone Tract by GIA field gemologists over five years. The gemological and chemical characterization indicates a wide range of blue color intensities, very consistent inclusion scenes, and no significant trace element differences between various sapphire-producing zones in Mogok. Such studies on reliable samples support the increasing demand for origin determination services by gemological laboratories.
Gemological Characterization of Peridot from Pyaung-Gaung in Mogok, Myanmar
Myanmar produces high-quality peridot of considerable size that possesses an attractive deep olive green color. A research team led by Montira Seneewong-Na-Ayutthaya examines peridot from the Pyaung-Gaung area and provides diagnostic inclusions and trace element chemistry that can separate this material from deposits in China and Pakistan.
History of Emerald Mining in the Habachtal Deposit of Austria, Part I
Karl Schmetzer details the mining history of Austria’s Habachtal region in part one of this two-part series. This article presents research using largely unpublished materials from Austrian and German archives to trace the various ownership transitions of this early emerald deposit.
Lab Notes
GIA laboratory staff members present their latest findings in the Lab Notes section, including a diamond faceted as the iconic Apple logo, two pairs of antique Mughal spectacles with diamond and emerald lenses, and tourmaline featuring a unique surface pattern resembling a circuit board.
Micro-World
The Micro-World section, dedicated to the inner world of gemstones, features a chondrodite crystal in Burmese red spinel, an excellent example of a polyp structure in natural black coral, spectacular wispy “horsetail” inclusions in demantoid, and a tourmaline with abundant colorless zoning with windmill structures.
Colored Stones Unearthed
Colored gemstone deposits are geologically diverse and provide important information on the composition and evolution of the earth. The debut of this new G&G column explores geological concepts related to the formation of colored stones from the crust-mantle transition and below. Future installments will appear on a periodic basis.
Gem News International
Finally, GNI correspondents from around the world report on renewed interest in mining activity at the Yogo sapphire deposit in Montana, the identification of blue zircon supposedly from a new deposit in Malawi, Rio Tinto’s final sale of pink and blue diamonds from Argyle, and “floating flower” inclusions in a bangle fashioned from aventurine quartz. @chapter:6 @chapter:0 @chapter:6


# Publication Year: 1989
# Title: Fall 1989 G&G Lab Notes
# Abstract: Imitation "Black Onyx" Chalcedony
Diamond with a Concave Table
Engraved Faceted Diamond Tablet
Diamond with Mysterious Wear
Insects as Jewelry
Chipped Pearls
"Demi-Pearl"
"Pinked" Pearl
Synthetic Star Ruby
Tanzanite with Iridescent Coating

To view the full section, download the PDF above. @chapter:52 @chapter:1 @chapter:52


# Publication Year: 1997
# Title: Summer 1997 G&G Book Reviews
# Abstract: “Cameos in Context The Benjamin Zucker Lectures, 1990”
Edited by Martin Henig and Michael Vickers, 102 pp., illus., publ. by The
Ashmolean Museum, Oxford, England, and Derek J. Content, Inc., Houlton, Maine, 1993, £27.50 (about US$46.00)

“Gemstones of North America, Volume III”
By John Sinkankas, 527 pp., illus., publ. by Geoscience Press, Tucson, AZ, 1997. US$65.00

“Diamond Exploration Techniques Emphasising Indicator Mineral Geochemistry and Canadian Examples”
By C. E. Fipke, J. J. Gurney, and R. O. Moore, 86 pp., illus., Geological Survey of Canada Bulletin No. 423, Ottawa, Ontario, Canada, 1995, Can$24.85

“An Overview of Production of Specific U.S. Gemstones”
By Gordon Austin, 41 pp., illus., Special Publication 14-95, U.S. Department of the Interior, U.S. Bureau of Mines, 1995, US$5.50

“Gemmologia Europa V—European Gemmologists on Rubies and Sapphires”
Edited by Margherita Superchi, 141 pp., illus, publ. by CISGEM, Milan, Italy, 1996, 35,000 lira (about US$20.00)

To view the full section, download the PDF above. @chapter:21 @chapter:0 @chapter:21


# Publication Year: 2015
# Title: Unusual Combination of Inclusions in Synthetic Star Sapphire
# Abstract: Figure 1. This 8.975 ct specimen was identified as synthetic star sapphire. Photo by Pragati Verma.

Recently, an 8.975 ct blue oval cabochon exhibiting asterism (figure 1) was submitted to the Indian Gemological Institute – Gem Testing Laboratory in Delhi for identification. Standard gemological testing revealed a spot RI of 1.76 and hydrostatic SG of 4.00. These properties were consistent with sapphire.

Figure 2. Three-directional needles intersecting at 60°/120° angles. Also notice the coarse
hexagonal boundary created by the gas bubbles surrounding the three-directional needles.
Photomicrograph by Meenakshi Chauhan; field of view 11.30 mm.
Microscopic examination at 25× magnification showed three-directional “needles” intersecting at 60°/120° angles (figure 2). Under 60× magnification, the three-directional needles appeared as a series of dots. The expected solid rutile needles were not resolved at the magnification used. These three-directional needles were further surrounded by a coarse hexagonal boundary (again, see figure 2) made up of gas bubbles (figure 3, left). The presence of the hexagonal boundary initially led to an impression of natural origin, but the presence of gas bubbles and chalky blue fluorescence under SWUV confirmed a synthetic origin. These three-directional needles (series of dots intersecting at 60°/120° angles) with possibly unresolved rutile needles are responsible for the six-rayed asterism. When the stone was checked in the DiamondView, it showed a dark blue ring around the gas bubbles (figure 3, right). This was the first time this author had seen such a reaction to gas bubbles in a synthetic material in the DiamondView.

Figure 3. Left: Gas bubbles appearing as whitish dots under 50× magnification. Right: DiamondView imaging of the gas bubbles. Notice the dark blue areas visible around the gas bubbles, which were inert to UV. This may indicate compositional variation where the whitish and dark areas are visible in the left-hand image. Photomicrograph and DiamondView image by Pragati Verma.
The three-directional intersecting needles that give rise to asterism in synthetic sapphire are a by-product of the titanium oxide added in the feed material for crystal growth. As mentioned above, the three-directional needles observed here were actually resolved microscopically as a series of dots, and the expected rutile needles were not observed. After growth, the boule was likely reheated, causing the previously disseminated titanium oxide to precipitate out as needles of rutile (R. Webster, Gems: Their Sources, Descriptions and Identification, 5th ed., rev. by P.G. Read, Butterworth-Heinemann, Oxford, UK).

When the sample was viewed in transmitted light, it appeared transparent in the center but translucent from the sides, resembling an eye (figure 4). No gas bubbles were visible in the center of the cabochon, but there were increasingly higher concentrations of gas bubbles toward the edges. Under SWUV, this material showed chalky blue fluorescence confined to the central transparent part. Such hexagonal patterns were previously reported in synthetic sapphire in G&G (Summer 2007 GNI, pp. 177–178). While observing any stone, one must not consider a single inclusion or characteristic, such as the hexagonal boundary observed here, as an indicator of natural or synthetic origin. There must be a thorough examination of all inclusions and properties (in this case, gas bubbles and chalky blue fluorescence under SWUV) to conclude the origin of a material.

Figure 4. Under fiber-optic light, the material showed an eye-like pattern, with a pink and transparent center and blue and translucent sides. Also notice the hexagonal boundary made from the gas bubbles.  Photomicrograph by Pragati Verma; field of view 22.94 mm. @chapter:19 @chapter:0 @chapter:19


# Publication Year: 1984
# Title: Lepidolite with Simulated Matrix
# Abstract: This article describes a crystal of gem-quality lepidolite (a lithium mica) with a simulated matrix.
Under magnification, numerous gas bubbles were observed in the glue that was used to attach the crystal to the matrix. The main crystal was identified as lepidolite by means of X-ray diffraction. @chapter:15 @chapter:0 @chapter:15


# Publication Year: 2013
# Title: Phosphorescence in Synthetic Sapphire
# Abstract: Figure 1. This 4.89 ct colorless synthetic sapphire was presented as a sapphire. Photo by Meenakshi Chauhan.

              A 4.89 ct colorless oval mixed-cut specimen was submitted as a sapphire to the Gem Testing Laboratory at the Indian Gemological Institute in Delhi for identification (figure 1). Standard gemological examination gave an RI of 1.760–1.768, with a uniaxial negative optic sign and a birefringence of 0.008, as well as a hydrostatic SG of 4.00. These properties were consistent with sapphire. While this specimen was eventually proven to be synthetic, its unusual characteristics—a lack of curved growth banding visible in the DTC DiamondView and very rare phosphorescence—called for instrumentation generally used in diamond identification.

	Figure 2. These fine, linear cracks near the girdle resemble long needles. Photomicrograph by Meenakshi Chauhan; magnified 40×.
Magnification showed what appeared to be long needles near the girdle, but closer examination revealed they were long cracks (figure 2). Rather than the Plato lines generally found in light-colored flame-fusion synthetic sapphires, the sample displayed two sharp planes under crossed polarizers. These planes, which had a noticeable separation in between, were visible in twinning lamellae position. Small stress knots near the table surface—but no physical inclusions—were also visible under crossed polarizers (figure 3). Such cracks, which are generally found on the surface of synthetic sapphire, may be due to stress during crystal growth.

	Figure 3. These small stress points, visible on the table between crossed polarizers, were confined to a small space. Photomicrograph by Meenakshi Chauhan; magnified 30×.
The sample was inert to long-wave UV radiation but showed a chalky blue fluorescence in short-wave UV, a common feature of synthetic sapphires. It also produced 30 seconds of phosphorescence—the first time this contributor has observed phosphorescence in sapphire, natural or synthetic. Examination in the DiamondView also showed an uncommon blue phosphorescence (figure 4), but it did not show curved growth banding—a fluorescence pattern normally seen in synthetic sapphire grown by the flame-fusion process.

	Figure 4. The colorless sample showed blue phosphorescence in the DiamondView, evidence of its synthetic origin. Image by Meenakshi Chauhan.
Identification could only be made on the basis of short-wave UV transmission analysis using the SSEF Diamond Spotter. When the instrument was switched on, short-wave UV radiation transmitted through the sample and the green dot glowed. The specimen’s transparency under the Diamond Spotter’s short-wave emission at 254 nm proved its synthetic origin, as natural sapphire does not transmit short-wave UV below 288 nm (S. Elen and E. Fritsch, “The separation of natural from synthetic colorless sapphire,” Spring 1999 G&G, pp. 30–41, http://dx.doi.org/10.5741/GEMS.35.1.30).

Despite the confirmation of synthetic origin, no conclusion could be made regarding the synthesis process used. Consistent with specimens grown by the Czochralski pulling method, there were no curved color bands, inclusions, or Plato lines. Conversely, the specimen’s chalky blue fluorescence and twinning are indicative of flame-fusion growth. These findings present the possibility of either (1) a synthesis process not yet explored by the gemological community or (2) growth by a known process, but with near perfection. While the DiamondView and Diamond Spotter were developed to analyze diamonds, they can also play a vital role in identifying other gemstones. @chapter:19 @chapter:1 @chapter:19


# Publication Year: 2003
# Title: Photomicrography for Gemologists
# Abstract: Just because you don’t see it, doesn’t mean it isn’t there.

Many areas in the jewelry industry—education, gemological research, lecturing, publication, and laboratory and inventory documentation, to name a few—either require or benefit from high-quality photomicrography. This article reviews the basic requirements of gemological photomicrography and introduces new techniques, advances, and discoveries in the field. Proper illumination is critical to obtaining the best possible photomicrographs of gemological subjects, as is the cleanliness of the photomicroscope and the area around it. Equally as important is an understanding of the features one sees and the role they might play in the identification process. This article is dedicated to Dr. Edward J. Gübelin, one of the great pioneers of gemological photomicrography and the first gemologist to truly appreciate the unparalleled beauty of gems in nature’s microcosm. @chapter:35 @chapter:1 @chapter:35


# Publication Year: 2018
# Title: Fancy Deep Brown-Orange CVD Synthetic Diamond
# Abstract: Figure 1. A face-up image showing the deep brown-orange bodycolor of a CVD-grown synthetic that has been irradiated and annealed. Photo by Robison McMurtry.

A 0.56 ct diamond (figure 1) was color graded as Fancy Deep brown-orange. The diamond was found to be a CVD-grown synthetic that had been irradiated and annealed, perhaps multiple times. DiamondView imaging (figure 2) showed the telltale striations of the CVD growth process, and the PL spectrum showed the SiV– (736/737 nm doublet) commonly found in CVD synthetics. The Vis-NIR spectrum (figure 3) showed a GR1 defect (the neutral vacancy center) and a peak at 594 nm that is commonly seen in diamonds that have been irradiated and annealed. This is in contrast to the normal irradiated and annealed CVD synthetic diamonds that show features related to nitrogen vacancies. The PL spectrum shows the NV0 (575 nm) and NV– (637 nm) peaks in relatively high concentrations compared to the diamond Raman line. In the infrared spectrum, a clear band at 1130 cm–1 and a peak at 1344 cm–1 indicate the presence of single substitutional nitrogen.

Figure 2. A DiamondView image reveals the characteristic growth striations of a CVD-grown synthetic diamond. Photo by Nicole Ahline.

Figure 3. The visible-NIR spectrum of the irradiated and annealed CVD synthetic shows the GR1 and 594 nm defects.
CVD-grown synthetic diamonds have been known to be irradiated (Fall 2014 Lab Notes, pp. 240–241; Fall 2015 Lab Notes, pp. 320–321) and also irradiated and annealed (J. Shigley et al., “Lab-grown colored diamonds from Chatham Created Gems,” Summer 2004 G&G, pp. 128–145). The irradiation and annealing performed on CVD synthetics is generally done on those with isolated nitrogen and produces a pink to red bodycolor. This color is caused by nitrogen-vacancy centers created when the vacancies produced by irradiation combine with the isolated nitrogen during the annealing process. In this case, the diamond showed a brown-orange bodycolor due to the combination of the isolated nitrogen and irradiation features. The stone in question contained isolated nitrogen, so it is possible that the intent was to create a pink to red color, but the treatment did not produce the expected results. Brown-orange color as a result of treatment has not been seen in a CVD synthetic diamond before, so the intentions of the treatment are as yet unknown. @chapter:9 @chapter:1 @chapter:9


# Publication Year: -
# Title: A New World of Glamour:  Former Model Launches Fine Jewelry Brand
# Abstract: Talk about persistence.

Vania Leles earned her GG from GIA in London in 2004 and promptly sent her curriculum vitae to Graff Diamonds on Bond Street for her dream job.

She sent it again … and again … and again.

The 15th time was the charm and she got a call for an interview.

“It was the only place I wanted to work,” she said. “Knowing what you want -- and why -- is important. Being persistent was key and led me to a wonderful career.”

Leles, a former fashion model who used to jet-set around the world for photo shoots and fashion shows, switched careers because she couldn’t resist the draw of diamonds and fine jewelry. Her interest in gems dates back to her memories of playing with her mother’s collection as a little girl.

“The seven years I spent as a model working in London, New York and Paris with couturiers, stylists and fashionistas exposed me to the world of exquisitely designed fine jewellery,” she said. “I was compelled [to change careers] by the fact that these beautiful pieces were made with vibrant and exciting stones.”

She was an in-house gemologist and brand ambassador for Graff, where she gained invaluable experience sourcing fine high-end jewelry for the design house’s exclusive clientele.

“Working with such valuable pieces gave me a keen eye for identifying and appreciating the rarest and most beautiful diamonds and gemstones in the world,” she said.

She credits her GIA education with giving her the essential skills she needed to embark on her gem and jewelry career, including being able to talk about the 4Cs in depth with clients.

“GIA empowered me and gave me the confidence to negotiate and engage with clients,” she said. “You need to transmit knowledge when negotiating. They need to feel secure that you know you understand your product.”

After two years at Graff, which is essentially a family-owned business, she decided she wanted to experience corporate structure and went to De Beers to create bespoke jewelry and source fine investment-purpose diamonds for clients, including royalty.

Three years later, she set her sights on the auction houses to gain expertise with all periods of jewelry. She was invited to join the Jewellery Department at Sotheby's, where she oversaw and participated in auctioning some of the world's most prestigious diamond and gemstone pieces, including the sale of the magnificent jewels of the Duchess of Windsor.

Leles appreciated the insight earned at these iconic jewelry businesses, but knew she wanted to launch her own company, so Vanleles Diamonds opened for business in 2011.

“I felt privileged to have been trusted enough to work in such fine companies, but I knew that ultimately my destiny was to source my own diamonds and gems -- and design my own jewelry for my trusted circle of clients,” she said. “Vanleles Diamonds is a labor of love.”

Her clients range from bankers and entrepreneurs in the tech industry, to fashion stylists and at least one member of a royal family.

“My clients look for quality, a jeweler they can trust and good value for his/her hard-earned money,” she said. “They are typically heavily involved in the fine details of the specifications and design of the piece and expect excellence service.”

Leles took some of GIA’s design courses, so she sketches ideas as she meets with clients to capture their concepts on paper.

“I have been fortunate enough to work with some of the most talented designers and craftsmen in the world and this has really helped me find my own voice as a jeweler,” she said. “We take the time to really get to know our client’s lifestyle and needs to create truly unique pieces of jewelry. Our passion is to create something personal and exceptional that tells a story within the client’s budget and requirements.”

Leles’ day starts at 7:30 a.m. with a quick jog, some strong coffee and getting up to speed on her trusted MacBook Air. She updates Vanleles Diamonds’ social media channels and checks the prices of precious metals and diamonds. Done with the computer, she makes her way to her workshop to check in with the master craftsmen working on their latest designs.

“I normally have my first client appointments by 11a.m. in our Belgravia studio and spend the rest of the day with clients, showing them a selection of the diamonds we’ve sourced that week and sketching jewelry that reflects their wishes.”

Leles, who was born in Guinea-Bissau, on the West African Coast, is proud of the fact that her company only buys conflict-free diamonds and is supporting the economic growth of Botswana and Namibia.

Ultimately, it is clear Leles’ persistence paid off.

“I love every aspect of my job – from sourcing rare, precious and ethical diamonds, to spending time with our clients to get the design absolutely perfect, to the pride of being able to deliver a true masterpiece of jewelry,” Leles said. “I love to be able to exceed our clients’ expectations of the amazing beauty of our products and the great value we offer.” @chapter:45 @chapter:2 @chapter:45


# Publication Year: -
# Title: Kunzite Description
# Abstract: Kunzite’s beauty is apparent in both its natural crystal and faceted forms. - Robert Weldon

                      Kunzite is the light pink to violetish purple variety of the mineral spodumene. It’s found in Afghanistan, Brazil, Madagascar, and the US state of California. The gem was named after pioneering gemologist George Frederick Kunz (1856-1932).

	This group of kunzite crystals was recovered from the Oceanview Mine in the Pala mining district of San Diego County, California. - Brendan Laurs
Kunzite has two perfect cleavage directions. It’s pleochroic, with the best color visible when you look down the length of the crystal. Cutters keep these factors in mind when they orient gems for finishing. They might also cut a kunzite deep to emphasize its pink to violet color.

	This lovely faceted kunzite displays an example of the best color this gem has to offer. - Robert Weldon
It is not unusual to find kunzite in large sizes. The Smithsonian Institution houses a faceted heart-shaped kunzite that weighs 880 carats.

Kunzite can be irradiated and then heat-treated to enhance its color. Both treated and natural color in kunzite can fade with exposure to heat and bright light. @chapter:2 @chapter:0 @chapter:2


# Publication Year: -
# Title: Sapphire Series Part 2: The Next Generation of Sapphire Crystal Growth Techniques
# Abstract: Figure 1. These photos show flame-fusion synthetic sapphire crystals, as-grown (left) and during growth in the furnace (right). Courtesy of Hrand Djevahirdjian, SA.

                      Previously we touched upon the basic science of sapphire—its mineralogy, chemistry, and physics—and also its appeal as a gemstone and in some industrial applications. Having looked at the first breakthroughs in synthesis, we now turn to the next generation of growth techniques developed to meet the demand for larger, more perfect crystals. As mentioned, much of the sapphire grown by the early flame-fusion method is used as high-purity feedstock for these advanced growth techniques (figure 1).

Bulk sapphire crystals are industrially produced using various methods and can be summarized broadly as either solution- or melt-grown. Solution growth involves using solvents such as water (hydrothermal) or other chemicals (flux) to create the crystal at a temperature below its melting point. Melt growth is achieved by bringing the Al2O3 all the way to its melting temperature (2040°C) in a crucible. Starting with a specifically oriented seed, a large crystal is formed either by pulling out a portion of the melt or by directionally cooling (gradient freezing) the melt in the crucible. Melt techniques are the focus here, as industry demands large, specifically oriented crystals. We will explore two pulling techniques, two gradient freezing techniques, and one hybrid.

In 1960, the Czochralski growth technique, a method introduced in 1918 that involves rotating and pulling a crystal out of a molten solution in a crucible, was first applied to sapphire. This technique is still very significant today for sapphire and a wide variety of other crystalline materials (including silicon) because it can produce some of the highest-quality crystals in terms of both purity and defects. The quality of these products stems mainly from the precisely controlled growth rate, made possible by carefully adjusting the power required for heating based on a mass-controlled feedback loop. Another factor that makes the Czochralski technique so invaluable is the ability to control the distribution of intentionally added impurities in “doped” crystals. This is accomplished by removing only a fraction of the molten solution rather than freezing the entire melt (figure 2).

	Figure 2. A Czochralski-grown synthetic ruby crystal is shown alongside a fabricated piece (left), and during removal from the growth station (right). Photos by Jennifer Stone-Sundberg.
In 1962, the edge-defined film-fed growth technique was first applied to sapphire. This allowed for the production of tubes, sheets, and other highly specified profiles by pulling the sapphire melt through a shaped die. As the demand for protective sapphire windows increases for a wide variety of end uses, this technique will continue to be refined (figure 3). The next part of the series will describe these applications more fully.

	Figure 3. Shown here are synthetic sapphire sheet crystals from edge-defined film-fed growth (left) and a growth machine that uses this technique (right). Photos courtesy of GT Advanced Technologies.

In 1964, Khachik Bagdasarov introduced a unique gradient-freeze technique in which the crystal is frozen from one side of the crucible to the other: the horizontal directional solidification method. Prof. Bagdasarov still uses this process to produce sapphire and other crystals. In 1967, Frederick Schmid introduced another gradient-freeze technique, the heat exchanger method, for making large ingots of various crystals (figure 4). This technique has yielded some of the finest optical-quality sapphire and is now owned by GT Advanced Technologies, which produces furnaces based on this technique under the brand name Advanced Sapphire Furnace.

	Figure 4. The two crystals on the top left were grown by the heat exchanger method, using the growth equipment pictured on the top right. A schematic of the growth process is shown on the bottom. Courtesy of GT Advanced Technologies.
The Kyropoulos growth method, which combines aspects of both the Czochralski and gradient-freeze techniques, was first applied to sapphire in 1980. Similar to the Czochralski technique, this method involves rotating a seed in contact with the melt, but the crystal is not pulled out of the melt. Instead, the melt inside the crucible is cooled in a very controlled fashion. The Kyropoulos technique has gained widespread use because of its ability to produce extremely large (up to 100 kg) high-quality sapphire crystals (figure 5).

	Figure 5. This crystal was grown by the Kyropoulos method, using the equipment shown on the right. Courtesy of GT Advanced Technologies.
Beyond timepiece bearings and scratch-resistant watch faces, what are the high-tech applications of sapphire? These uses, which capitalize on the material’s desirable mechanical, optical, physical, chemical, and structural properties, will be discussed in the third part of this series. @chapter:19 @chapter:1 @chapter:19


# Publication Year: 2016
# Title: Chalcedony with Quartz Windows
# Abstract: The trigonal windows of quartz found throughout this translucent white chalcedony displayed vibrant interference colors when examined between crossed polars. The black triangles in the lower left corner are also quartz. Photomicrograph by John I. Koivula; field of view 15.5 mm.

	A translucent white chalcedony specimen containing a few small transparent quartz crystals was fashioned into a decorative polished plate by Falk Burger (Hard Works, Tucson, Arizona). One intriguing feature of this piece is that most of the transparent quartz crystals were aligned with their c-axes parallel to each other. When they were transected perpendicular to this axis during the polishing process, angular transparent windows were created, each displaying trigonal symmetry within their otherwise translucent chalcedony host. Interestingly, even though the white chalcedony was polished into a plate, it still showed a rather curious angular-looking three-dimensional texture. When examined between crossed polars, the triangular quartz windows ignited with vibrant interference colors, as seen in the accompanying image, due to Brazil-law twinning in the crystals. @chapter:26 @chapter:0 @chapter:26


# Publication Year: 2015
# Title: Larger Optic Disks
# Abstract: Nature’s Geometry

In this video, Brian Cook explains the next step in the evolution of his unique optic disks: larger pieces that display a striking rainbow of concentric color bands.
At the 2014 GJX show, Brian Cook (Nature’s Geometry, Graton, California) showed us innovative optical disks made of colorless quartz featuring a drilled tube containing pieces of brightly colored gem and mineral rough. The tube is subsequently sealed with clear quartz. When the disk is viewed face up, the insert’s reflections permeate the disk with bright color.

For this year’s show, Cook’s “wheel of light” design evolved into larger sizes with more intriguing reflective effects. Seen front-on, the new disks produced concentric colored reflections. The first we saw measured approximately 4 cm (1.57 in.) in diameter and featured Brazilian emerald, Paraíba tourmaline, and haüyne insets (haüyne is a brittle sodium calcium sulfate that provides rich blues). One innovative feature is that the viewer could see different colors depending on the viewing direction. From various directions the disk was suffused with bands of rich green, electric blue, or royal blue color.

According to Cook, this new product takes the color and amplifies it. There is a chamber within the quartz, which he polishes before inserting the colors he wants. Because no faceting is involved, all the colors are blended together. Cook said his passion for Paraíba tourmaline was the starting point.

Figure 1. This edge-on view of the “wheel of light” reveals its construction. Photo by Duncan Pay/GIA; courtesy of Nature’s Geometry.
Cook unwrapped a larger disk, approximately 8 cm (3.15 in.) in diameter. Viewed edge-on, the chamber’s pattern of colored rough gems and minerals was revealed (figure 1). Cook had arranged a complete spectrum of rainbow colors in sequence: ruby, spessartine garnet, a gold nugget, Paraíba tourmaline, and haüyne (figure 2).

Figure 2. Seen end-on, the larger disk displays the spectrum as concentric colors. Photo by Duncan Pay/GIA, courtesy of Nature’s Geometry.
Cook also showed us a smaller optic disk set in a handmade platinum pendant set with diamond and melee-size Paraíba tourmaline from the Brazil Paraíba mine in Parelhas, Rio Grande do Norte. This piece combined the unusual optic effects of the center, which featured more Paraíba tourmaline and haüyne, with a conventional suite, which besides the pendant included a pair of earrings set with similar optic disks. @chapter:10 @chapter:0 @chapter:10


# Publication Year: 2020
# Title: Trapiche-Like Pattern in an Emerald from Pakistan
# Abstract: A distinct near-colorless hexagonal core with radiating fibrous arms is evident in this Pakistani emerald from Swat Valley. Photomicrograph by Charuwan Khowpong; field of view 1.40 mm.

GIA’s colored stone research collection contains many unique samples. The emerald sample shown above was mined at Swat Valley in the Khyber Pakhtunkhwa region of Pakistan and fabricated by polishing two parallel windows perpendicular to the c-axis of the hexagonal crystal in order to show its inclusions. The sample weighed 0.47 ct prior to fabrication and 0.36 ct after processing.
At first glance, nothing unusual was noted in this sample, but when correctly illuminated under the microscope it revealed a pattern that could easily pass for trapiche. The stone showed radiating zones of turbid growth with six-fold symmetry. This makes it a trapiche-like stone rather than a true trapiche, which has distinct arms that separate the growth zones. While classic trapiche patterns are mostly associated with Colombian emeralds, the Swat region also produces emeralds with radiating black intergrowths. Still, this structure was very different from the trapiche structure previously documented in some emeralds from Pakistan (Fall 2019 Gem News International, “Trapiche emerald from Swat Valley, Pakistan,” pp. 441–442). In this case, the distinct growth feature consisted of a colorless hexagonal core from which six-rayed fibrous arms extended. Lighting was an important consideration in maximizing the color in this stone, and the features were fully observed using brightfield illumination. This was a wonderful example of a pattern rarely encountered in emeralds. @chapter:13 @chapter:0 @chapter:13


# Publication Year: 2021
# Title: Monazite (?) in Quartz
# Abstract: Figure 1. This 10.54 ct rock crystal quartz is host to a transparent yellow mineral inclusion. Photo by Annie Haynes.

We recently examined an interesting 10.54 ct transparent, colorless, square modified step cut with a slightly convex table facet (figure 1). The faceted rock crystal quartz host, measuring 11.82 × 11.77 × 9.57 mm, is from Itinga in Minas Gerais, Brazil, and came to us from Luciana Barbosa at the Gemological Center in Asheville, North Carolina.

Figure 2. The transparent yellow monazite (?) inclusion in the rock crystal quartz and the stress cracks immediately surrounding it are both clearly visible in this image. Photomicrograph by Nathan Renfro; field of view 4.86 mm.
The gem played host to an eye-visible transparent yellow crystal located near its center, which was visible from several directions. On examination with a gemological microscope, we observed a transparent yellow angular crystal of what appeared to be monazite, with a skirt of small stress cracks, suspended in the quartz (figure 2).
Laser Raman microspectrometry was not able to identify the inclusion because it was too deep in the host; all it returned were quartz peaks. Energy-dispersive X-ray fluorescence (EDXRF) also failed to produce hints of unusual chemistry on the inclusion. After several attempts at Raman and EDXRF, we realized that destructive analysis would be needed to clearly identify the yellow crystal, but destructive analysis was not possible.

Figure 3. The monazite (?) inclusion shows its birefringent (anisotropic) nature with bright interference colors in polarized light. Photomicrograph by Nathan Renfro; field of view 3.06 mm.
As a result, we turned to optical mineralogy and the crystal habit shown by the well-formed inclusion. Morphologically, the inclusion looked like monazite crystals we have encountered in the past, and it appeared to be monoclinic. The yellow color also suggested monazite. The inclusion showed its birefringent (anisotropic) nature with bright interference colors in polarized light (figure 3). A small condensing lens was used to pull a partial biaxial interference figure from the inclusion. The crystal had weak pleochroism, and a Becke line test showed that the inclusion had a higher refractive index than the surrounding host quartz. All of these findings could lead to its identification as monazite. But there is still a nagging uncertainty, so we are left with “monazite (?).” @chapter:15 @chapter:0 @chapter:15


# Publication Year: 2019
# Title: Star-Like Growth in Natural Yellow Sapphire
# Abstract: A group of six-rayed stars in a faceted yellow sapphire. Photomicrograph by Ungkhana Atikarnsakul; field of view 1.5 mm.

Internal growth structures (commonly referred to as graining) observed in transparent gemstones often reflect a gem’s crystallography. Graining can assist in distinguishing natural from synthetic gem materials. For example, a synthetic flame-fusion corundum commonly shows curved growth lines, while natural and flux-grown corundum usually shows straight, angular, or hexagonal growth patterns.
Recently, the author examined an 8.01 ct faceted yellow stone that had gemological properties consistent with sapphire. The most distinctive feature found in this stone was internal graining displaying as six-rayed stars (see above). It is interesting to note that the angle of each ray was 60 degrees, consistent with corundum’s trigonal crystal structure. This is the first time the author has encountered a star-like graining pattern in natural sapphire. @chapter:19 @chapter:0 @chapter:19


# Publication Year: 2020
# Title: Tucson 2020 Overview
# Abstract: Figure 1. A busy booth on the first day of the AGTA show. Photo by Tao Hsu.
In early February, despite the early phase of the COVID-19 outbreak, the Tucson shows were well attended and sales were brisk. Several vendors indicated that they had their biggest single day of sales ever this year (figure 1). This anecdotal evidence was supported by the strong demand for identification and origin services reported by the GIA Show Service Lab. This year, it was hard to identify any one particular item leading demand or any game-changing new gem material finds. Instead, we found that vendors were carrying high-quality material in terms of color, clarity, and cut. In fact, many were carrying items that had been meticulously carved, fantasy-cut, or recut for ideal proportions (figure 2).

Figure 2. A 72 ct gem silica carving by Nick Alexander showing a highly desirable intense shade of blue. The material is from the Ray mine in Arizona. Photo by Kevin Schumacher; courtesy of Nick Alexander.

Figure 3. A suite of the popular teal blue Montana sapphires from Rock Creek. The center stone is 11.03 ct, and the other 14 stones total 8.38 carats. Photo by Jennifer Stone-Sundberg; courtesy of Pala International.
Surpassing its strong momentum from the past few years, teal blue sapphire from Montana was a prominent and well sought-after item (figure 3). Sapphire was doing very well at the shows, including parti-colored, fancy-colored (electric colors such as fuchsia and pinks as well as pastels such as lavender), and slabs displaying zoning or trapiche-like patterning (figure 4).

Figure 4. Left: This set of 110 Australian sapphire “fancies” in 3 mm sizes was collected over several years. Right: A pair of trapiche-like Australian sapphire slices. Photos by Jennifer Stone-Sundberg; courtesy of Terry Coldham.

Figure 5. A 0.33 ct emerald from Malysheva, Russia, offered by Dudley Blauwet at the AGTA show. Photo by Kevin Schumacher.
Emerald from around the world could be found, including some untreated smaller sizes from Russia (figure 5), melee and small-sized finished stones from Pakistan, attractive material from Ethiopia, and an abundance of material in a wide variety of color, clarity, and size from Colombia, Brazil, and Zambia.
Outstanding brilliant green garnets in both demantoid and tsavorite varieties were available, including several larger-sized, ideally colored Russian demantoids (figure 6).

Figure 6. A 6.73 ct round brilliant Russian demantoid of top quality showing a horsetail inclusion. Photo © Christian Wild.

Figure 7. Deep blue aquamarine from Nasarawa, Nigeria (left to right: 1.94, 2.84, and 1.84 ct). Photo by Emily Lane; courtesy of Jeff Hapeman.
As “Classic Blue” is the Pantone color of the year and varieties of blue gemstones are very popular in general, gems prominently displaying a blue hue could be found throughout the shows. Along with sapphire, deep blue aquamarine from Nigeria (figure 7) was particularly popular, and many vendors displayed blue zircon, gem silica (again, see figure 2), apatite, cobalt spinel, blue topaz, haüyne, turquoise, blue moonstone, and lapis in their cases.
Electric-colored accent stones and melee in materials such as sapphire, spinel, apatite, and garnet varieties tsavorite and demantoid were easy to find both loose and in finished pieces (figure 8).

Figure 8. Sea star pendant by Paula Crevoshay featuring 4.04 carats of ruby, 5.06 carats of lavender sapphire, 9.40 carats of purple sapphire, 3.87 carats of fuchsia sapphire, 6.79 carats of crystal spinel, and 0.43 carats of amethyst, set in 18K yellow gold. Photo by Emily Lane; courtesy of Paula Crevoshay.

Figure 9. Parti-colored sapphire slices from Montana (left) and Australia (right). Photos by Jennifer Stone-Sundberg; courtesy of Warren Boyd (left) and Terry Coldham (right).
As has been the case for the past couple of years, gem slices in a variety of materials, shapes, and price points were very popular in both the AGTA and GJX shows. These are attractive to many designers, whether they are working with higher-price-point material such as parti-colored sapphire (figure 9), diamond, and trapiche emerald, or more moderately priced material including amethyst, rhodochrosite, and petrified wood.

Figure 10. Fluorescent hyalite opal flower pendant by Loretta Castoro, photographed in daylight-equivalent (left) and lower-power daylight-equivalent light with added short-wave UV light (right). The 12.63 ct fluorescent opal is from Zacatecas, Mexico. It is set in 18K yellow gold and has 48 yellow diamond accents (1.14 carats total) and 72 white diamond accents (1.27 carats total). Photos by Robert Weldon; courtesy of Loretta Castoro.

Figure 11. An extremely diverse selection of unusual stones was on display at the GJX show. Left: Bright green fluorite offered by a European vendor; photo by Tao Hsu. Right: Bicolor chrysoberyl carried by United Colour Stone Co. from Bangkok; photo by Jennifer Stone-Sundberg.
As always, Tucson was the place to find the unusual and phenomenal, with several vendors carrying exotic gem materials such as fluorescent hyalite opal (figure 10), star peridot, brilliant green fluorite (figure 11, left), hackmanite, triphylite, grandidierite, axinite, and an array of bicolor stones in materials such as garnet, chrysoberyl (figure 11, right), tanzanite, and sphene.

View Gallery

An Inside Look at the 2020 Tucson Shows
2020 also marked the first Tucson edition of the Ethical Gem Fair. The exhibitors showed a wide range of gemstones, prices, and origins. They were all united in their commitment to responsible sourcing, traceability, transparency, and social awareness. The variety of exhibitors reflected the different approaches taken to address these diverse challenges around the world. During its inaugural Tucson show, the Ethical Gem Fair mainly attracted young independent jewelry designers looking for gems with a transparent chain of custody from the mine to their use in finished jewelry. @chapter:38 @chapter:3 @chapter:38


# Publication Year: -
# Title: Pearls: Forever Fashionable
# Abstract: Courtesy of Atelier Marisa

                      A jewelry store’s pearl counter is a fascinating place. These enchanting gems have represented beauty and perfection ever since man discovered them in ancient times. They have been the subject of countless tales of history, beauty, myth and elegance.

The Arabian Gulf was the world’s first source of natural pearls and remained so for centuries. Natural pearls from the Gulf are notable for their transparent and high-luster nacre. Together with pearls from the Red Sea and the Strait of Manaar, they have been referred to as “oriental pearls” and are highly valued.

Part of a pearl’s appeal is its organic origins: It comes from a living animal, a mollusk. And because pearls are slightly porous, they warm up against the skin as they are worn. The wearer and the gems become one.

The exciting array of pearl choices available today can be overwhelming. When you combine the variety of colors, sizes and shapes with metals and other gemstones in rings, necklaces and earrings, the possible combinations are practically endless.

So before you set off to buy pearl jewelry, you should understand the basics. Are you looking for natural or cultured pearls? Do you know what to look for in terms of size, luster and color? What price range are you interested in? How are some pearls treated to enhance their appearance? These are all good questions to consider before you begin to shop.

A retailer who knows the types of natural and cultured pearls that are available and the factors that determine their value will be an invaluable resource to you as you explore pearls.

In the meantime, here are some basics to get you started.

Pearls are natural or cultured and grow in mollusks that can live in either saltwater or fresh water. They are made up of layers of calcium carbonate most popularly in the form of nacre, a natural substance produced by pearl oysters that coats the inside of the animal’s shell. This beautiful, lustrous nacre is the very essence of a pearl.

Natural Saltwater Pearls
Natural pearls are extremely rare. The Arabian Gulf is the most important source for natural pearls – 70-80 percent of all pearls came from there until the 1950s. The island of Bahrain was a center for trade with northwest India and what is now the modern Middle East. A 4,000-year-old pearl was uncovered in 1989, and excavations at the ancient Bahrain’s Dilmun settlement have confirmed that pearl fishing has been going on for at least 3,000 years.

Natural saltwater pearls from the Arabian Gulf come from the Pinctada radiata and Pinctada margaritifera. Persian Gulf pearls range in color from white to dark cream and tend to be more yellow than those from the Red Sea and Strait of Manaar, whose characteristic colors are very light yellow, cream and very light pink. The Red Sea also produces some pearls in darker hues that range from intense pink to light to dark violet.

Natural saltwater pearls are also found occasionally in Baja California, Venezuela, Myanmar, China, Japan, India, French Polynesia, Australia and Africa – the same regions that have cultured pearl industries.

Saltwater Cultured Pearls
If you ask someone to describe an Akoya pearl, they will most likely describe a white, round, lustrous gem cultured in Japan and China in Pinctada fucata (martensii). Most akoya cultured pearls are white or cream and some have hints of rosé (pink) or green. The akoya oyster is relatively small, so it doesn’t usually produce a cultured pearl larger than 9 mm. Natural pearls from Pinctada fucata (matensii) are extremely rare.

Tahitian cultured pearls have only been on the market since the 1970s and come in colors including eggplant purple, peacock green, metallic gray and grayish blue. The mollusk that produces them (Pinctada margaritifera) is native to French Polynesia and is farmed there and in the Cook Islands, Fiji, Australia and New Zealand.

South Sea cultured pearls come from one of the world’s largest pearl oyster (Pinctada maxima), which produces cultured pearls that can measure 15 mm or larger. They are farmed in Australia, Burma, the Philippines and Indonesia. While South Sea cultured pearls occur in other colors, silver, white and yellow (sometimes referred to as “golden”) are the most common.

Freshwater Cultured Pearls
Cultured pearl farmers in China produce the overwhelming majority of cultured freshwater pearls. These cultured pearls vary widely in color and are generally more affordable than saltwater cultured pearls. Sizes are comparable to akoya cultured pearls, with a range between 2 mm and 13 mm, although larger sizes are now available. Fascinating new cultured pearls from fire balls to soufflés have been emerging from China in a dramatic array of colors.

The chief cultured pearl-producing mussel in the U.S. is the “washboard” M. nervosa. Only a small fraction of the total number of freshwater cultured pearls produced come from the U.S.

What to look for when picking out pearls
GIA, the world’s foremost authority on diamonds and gems, created a pearl description system, in order to evaluate the quality of pearls. GIA’s 7 Value Factors include Size, Shape, Color, Luster, Surface, and Nacre. Be sure to ask your sales associate to go through these with you.

Size: As with other gems, a larger pearl (measured in millimeters) is typically more valuable. The larger the pearl, the more rare and costly it tends to be. But fine quality pearls can be small, and low quality pearls can be large, so a pearl’s ultimate worth depends on how it combines the complete mix of value factors.

Shape: While round is the most familiar shape, pearls come in a parade of forms (round, near round, oval, button, drop, semi-baroque, baroque). No matter what its shape, if a pearl is or symmetrical, it will be more valuable than one that’s irregular.

Color: A pearl’s color is a combination of its dominant bodycolor, overtone, the subtle colours that seem to come from within the pearl, and orient, the “play of color” you see when the pearl moves.. Cultured pearls display a broad palette of subtle hues, ranging from warm (yellow, orange and pink) to cool (blue, green and violet).

Luster: The intensity of light reflected from or just below the surface of the pearl, its luster, contributes the most to the beauty of a pearl. The effect is an inner glow from the heart of the gem. A pearl with excellent luster will look bright and shiny, while one with poor luster is dull and far less valuable. Fine akoyas tend to display a bright, mirror-like gloss. Other pearls tend to feature a softer, satiny luster.

Surface: A completely clean pearl is a rare treasure. Since rarity influences value, the prices of such pearls run extremely high. The number, nature, and location of surface characteristics (abrasions, bumps, chips, cracks, etc.) can affect the value of any pearl. Numerous or severe surface irregularities – such as chips or gaps – can threaten the durability of the pearl and cause it to break or peel and considerably lower its quality and value. If a surface characteristic is minor and located near a pearl’s drill hole, where it’s less noticeable, it will detract less from the pearl’s appearance and ultimate value.

Other value factors can minimize the effect of surface characteristics on a pearl’s worth. If the pearl is large and highly lustrous, for example, these pluses can outweigh a slight surface characteristic or two. In fact, excellent luster makes some surface characteristics less noticeable.

Nacre: Nacre is the very essence of the pearl itself and nacre thickness does affect the value. Quality cultured pearls have ample thickness to allow the pearl to display its beauty.

Matching: The uniformity of the appearance of pearls in strands and multi-pearl pieces is called matching.

How to Care for Pearls
Now that you’ve gotten your pearls, you should know a few things about taking care of them.

To retain their beauty, they need a certain amount of moisture, which is why you should avoid storing pearls in an airtight or overly dry environment, such as a bank safety deposit box. The human body conveniently provides just the right amount of moisture. Worn often and properly cared for, pearls can look as good in 50 years as they did the day they left the store.

Pearls are not the most durable of gems. Most everyday items at home and in the office are tougher than pearls, so careless contact can cause damage them over time. Chemicals are the primary threat. Perfume, makeup and hairspray contain ingredients that can eat away the nacre, permanently dulling it. Many cleaning products contain chemicals such as ammonia and chlorine, which can pit gold alloys and quickly damage pearls. Chlorinated swimming pool water is also hazardous. Avoid wearing pearl jewellery when cleaning the house or doing yard work.

The best way to clean your pearls is with a soft damp cloth, ideally after each time you wear them.

Are you ready to learn more?
Consider taking a course to gain a deeper understanding of this fascinating gem. GIA offers an online pearl course in its gemmology eLearning curriculum that you can take from the comfort of your home. It’s a fascinating look at the world of pearls, including their origin, how they get to market, and the GIA 7 Value Factors used to describe their quality. Or, you can choose to take a one-day instructor-led GIA Pearl Grading class where you’ll learn to evaluate the quality of freshwater, South Sea and Tahitian pearls. @chapter:53 @chapter:4 @chapter:53


# Publication Year: -
# Title: Topaz Journey
# Abstract: Few people outside the gem industry realize the true nature of a gemstone’s journey from the mine to the counter of a store. Whether the gem is being offered to consumer’s at a traditional jewelry store’s counter, an internet shopping site, or a television broadcast the journey always involves a great deal of effort.  Tons of earth and countless hours of labor are needed to being a gem from mine to market. @chapter:38 @chapter:3 @chapter:38


# Publication Year: 1988
# Title: Winter 1988 G&G Lab Notes
# Abstract: Imitation Dyed Black Chalcedony Beads
Imitation Crystal Diamond
Diamond with Radiation Stains
Mysteriously Damaged Diamond
Dyed Grossularite Garnet
Walrus Ivory
Irradiated Cultured Pearls
Pear-Shaped Saltwater Pearl
Large Flux-Grown Synthetic Ruby
Synthetic Spinel Represented as Topaz
Synthetics and "Modern" Gems in Period Jewelry

To view the full section, download the PDF above. @chapter:16 @chapter:1 @chapter:16


# Publication Year: -
# Title: G&G Announces Most Valuable Article Awards
# Abstract: A matched pair of Kashmir sapphires, approximately 7 carats total. Photo by Robert Weldon/GIA. Courtesy of Amba Gem Corporation

Gems & Gemology is pleased to announce the winners of the Dr. Edward J. Gübelin Most Valuable Article Awards for 2019. G&G’s Most Valuable Article Award recognizes the three most groundbreaking articles from the previous year. For the first time in the competition’s history, the ballots were cast by the journal’s editorial review board.
First place went to “Geographic Origin Determination of Blue Sapphire,” by Aaron Palke, Sudarat Saeseaw, Nathan Renfro, Ziyin Sun and Shane McClure. This article, from the Winter 2019 special issue on geographic origin, detailed GIA’s methodology for establishing the origin of blue sapphire.

Aaron Palke is senior manager of research at GIA in Carlsbad, California. He holds a Ph.D. in geology from Stanford University.

Sudarat Saeseaw is a senior manager of colored stone identification at GIA in Bangkok. Saeseaw received her master’s degree in analytical chemistry from Mahidol University in Thailand.

Nathan Renfro is manager of colored stones identification at GIA in Carlsbad. He earned a bachelor’s degree in geology from Appalachian State University in North Carolina.

Ziyin Sun is a research associate in the gem identification department at GIA in Carlsbad. He holds a bachelor’s degree in chemistry and a master’s degree in analytic chemistry from Nanjing University in China.

Shane McClure is global director of colored stone services at GIA in Carlsbad and co-editor of G&G’s Lab Notes section. He is well known for his many articles and lectures on gem identification.

A variety of rubies from Niassa and Montepuez in northern Mozambique that were mined in 2009–2010. They include untreated and heated stones weighing between 1.07 and 4.62 ct. Photo by Robert Weldon/GIA. Courtesy of Tommy Wu, Shire Trading Ltd
Two articles tied for second place. From the Summer 2019 issue was “A Decade of Ruby from Mozambique: A Review,” by Wim Vertriest and Sudarat Saeseaw. This report reviewed the mining history, market impact and properties of ruby from northern Mozambique near Montepuez, now the world’s most productive source.
Wim Vertriest is supervisor of field gemology at GIA in Bangkok. Vertriest has visited gemstone mining areas worldwide and oversees the field gemology department and curates GIA’s colored stone research collection in Bangkok. He obtained a master’s degree in geology (geodynamics and geofluids) from KU Leuven in Belgium.

Sudarat Saeseaw was profiled in the first-place entry.

Tranquil reflecting pools add to the symmetry of the Taj Mahal. Photo by Robert Weldon/GIA
Sharing second-place honors was “Gemstones in the Era of the Taj Mahal and the Mughals,” by Dona Mary Dirlam, Chris Rogers and Robert Weldon. This Fall 2019 piece explored the gem ornamentation of an iconic landmark, with a look at the jewels of the Mughal dynasty.

Dona Dirlam is librarian emerita at GIA’s Richard T. Liddicoat Gemological Library and Information Center in Carlsbad, California, where she established and expanded the collection known as the world’s leading resource center for gems, gemology and jewelry. Dirlam holds a master’s in geology and geophysics from the University of Wisconsin, Madison.

Chris Rogers is a research librarian at GIA’s Richard T. Liddicoat Gemological Library and Information Center. She holds a bachelor’s degree in English from San Diego State University and a master’s in library and information science from San Jose State University.

Robert Weldon is director of GIA’s Richard T. Liddicoat Gemological Library and Information Center. He is well known for his gem photography and has contributed to scores of international publications and several gem-related books.
Congratulations to all of this year’s winning authors! @chapter:4 @chapter:0 @chapter:4


# Publication Year: 1998
# Title: Spring 1998 G&G Book Reviews
# Abstract: “Cultured Pearls: The First Hundred Years”
By Andy Müller for Golay Buchel, 142 pp., illus., publ. by The Golay Buchel Group, Lausanne, Switzerland, 1997. US$60.00

“Dana’s New Minerology, 8th Edition”
Rewritten by Richard V. Gaines, H. Catherine Skinner, Eugene E. Foord, Brian Mason, and Abraham Rosenzweig, 1,874 pp., illus., publ. by John Wiley & Sons, New York, 1997. US$250.00

“Mineral Collector’s Handbook”
By Barry Krause, 192 pp., illus., publ. by Sterling Publishing Company, New York, 1996. US$24.95

“Gemme del Vicentino (Gems of Vicenza)”
By Matteo Boscardin and Ottaviano Violati Tescari, 114 pp., illus., publ. by Zannato Civic Museum, Montecchio Maggiore, 1996, US$14.00 (in Italian, with English summary)

To view the full section, download the PDF above. @chapter:31 @chapter:2 @chapter:31