# Publication Year: -
# Title: Sapphire Quality Factors
# Abstract: This sapphire from Kashmir has an intense velvety blue color. – Photo: Robert Weldon/GIA.

Sapphire is one of the Big three of jewelry colored gemstones—the other two are ruby and emerald. A durable stone that’s designated as a birthstone for September, it captures jewelry buyers with its practicality and aura of romance.

Corundum is the mineral species that includes both sapphire and ruby as varieties. Red corundum is known as ruby and all other colored corundum (including colorless, or white sapphire as it is known in the trade) is sapphire, although blue is the most well-known.
Colors of Sapphire
Sapphire is generally known as a blue gemstone but surprisingly it comes in a wide range of colors and quality variations. In general, the more intense and uniform the color is, the more valuable the stone.

Sapphires that are not blue are known as fancy sapphires, and may be any color—except red (which is a ruby). The fancy sapphire colors are: pink, orange, yellow, green, purple, and violet. There truly is a different color of sapphire to suit anyone’s taste!
Blue Sapphires
Color has the greatest influence on a sapphire’s value, and preferred sapphires have strong to vivid color saturation. The most valued blue sapphires are velvety blue to violetish blue, in medium to medium-dark tones. Sapphires with these qualities command the highest prices per carat. Less valuable blue sapphires might also be grayish, too light, or too dark.

Madagascar is a relative newcomer as a major sapphire source, but its stones can have an intense blue color that rivals the finest from more traditional sources. - Copyright: GIA & Tino Hammid
What is a Padparadscha Sapphire?

An extremely rare and collectible variety that is a mix of pink and orange is known in the trade as padparadscha. Such gems typically have a high value—much higher than many other types of fancy sapphires. Their color can be hard to describe. Some people say padparadscha sapphire colors should be called salmon or sunset. But the word padparadscha itself derives from the Sanskrit language and refers to the rich color of a lotus blossom.

Those who deal in these gemstones usually agree that padparadscha sapphires should range from light to medium pinkish orange to orange-pink.

Pink and Purple Sapphires

Pink sapphires range from light red (pink) to light purple with weak to intense color saturation which fall out of the color ranges for ruby or purple sapphire. Purple sapphires always have purple as the dominant color. They range from medium to dark reddish purple to violetish purple with weak to vivid color saturation.The major fancy sapphire color categories are padparadscha, pink and purple, orange and yellow, green, and colorless and black. Each category has its own color range, causes of color, and market.

Some pink sapphires have intensely saturated color. -- Photo: Lydia Dyer, gem courtesy of John Dyer & Co.
Yellow to Orange Sapphires

Yellow sapphire is also available in a variety color saturations from yellow to orangy yellow and in light to dark tones, while orange sapphires have deep golden, to mandarin, and deep orange colors.

Yellow sapphires may be affected by other colors within the same gem and can range from light to dark greenish yellow to orangy yellow with weak to intense color saturation. The finest yellow sapphire is yellow to orangy yellow with vivid saturation.

Orange sapphires range from yellowish orange to reddish orange. The finest orange sapphires are strong, pure orange to red-orange with medium tone and vivid saturation.

These sapphires range from yellow to a deep yellow-orange color called golden to highly saturated reddish orange. - Copyright: GIA & Tino Hammid. Courtesy: Varujan Arslanyan
Green Sapphires

Commercial-grade sapphires may contain a less desirable greenish blue color or strong greenish blue that is visible as you view the gem. Uniformly green sapphires that are saturated in color are actually rare and many collectors prize them. In green sapphires, a mix of yellow and blue sapphire accounts for the color a person sees.

Color Change Sapphires

Color-change sapphires are corundum’s chameleons—stones that change color under different lighting. Under daylight equivalent (fluorescent or LED daylight-balanced) light, the typical color-change sapphire’s basic color ranges from blue to violet. Under incandescent light, it ranges from violetish purple to strongly reddish purple. Some rare color-change sapphires change from green in daylight to reddish brown in incandescent light.

When gem experts judge color-change sapphires, they describe the color change as weak, moderate, or strong. The strength of the stone’s color change is the most important quality factor affecting its value.

The color of star corundum has a great effect on its value, though it is understood that miniscule inclusions are the cause of the asterism. They can affect transparency and color, and only very rare, exceptional gems exhibit transparency, depth of color and asterism. As such, the best star corundum has a crisp, distinct star against strongly saturated color. If the color is too light, it doesn’t provide enough contrast for the star’s rays, and the star will be less visible.

Star corundum can be red, pink, blue, black, gray, brown, purple, or yellow—practically every color under the sun. The term “star sapphire” encompasses all colors of star corundum except red, which is called star ruby.

Naturally, some colors of star corundum are valued more highly than others. In general, the most prized colors are the same as the colors most valued in non-phenomenal corundum: red and blue.

Trade terms based on sources can represent certain colors and qualities that are associated with a stone’s source, generally they refer to the finest stones from that source. But a single source never consistently yields gems that are all the same color and quality. In fact, the descriptive term might represent only a small percentage of its production.
New sources can produce material that is very similar to gems from classical sources or with a slightly different, but just as beautiful, appearance.

Sapphire Clarity
Blue sapphires typically have some inclusions, but they generally have better clarity than rubies. Blue sapphires with extremely high clarity are rare, and very valuable.

Several types of inclusions are found in sapphires. Among these are long thin mineral inclusions called needles. Fine needles are called silk when they occur as the mineral rutile in intersecting groups. Other clarity characteristics in sapphire are included mineral crystals, partially healed breaks that look like fingerprints, color zoning, and color banding.

These long, thin, intersecting inclusions of the mineral rutile are called silk. This arrangement can produce the star effect in corundum.

Generally, inclusions make a stone less valuable. Price can drop substantially if the inclusions threaten the stone’s durability. Even so, inclusions can actually increase the value of some sapphires. Many of the most valuable Kashmir sapphires contain tiny inclusions that give them a velvety appearance. They scatter light, causing the coveted visual effect without negatively affecting the gem’s transparency.
Star Sapphire

Star sapphires and star rubies belong to the phenomenal corundum category. The star effect is called asterism. It’s caused by reflections from tiny, needle-like inclusions that are oriented in several specific directions. Stars are usually made up of 2, 3, or 6 intersecting bands, resulting in 4, 6, or (rarely) 12 rays.

Tiny inclusions create magnificent reflections of light known as the star effect. - © GIA & Tino Hammid, courtesy Benjamin Zucker

Star sapphires usually have stars have 6 rays, and 12-rayed stars are quite rare. Two different sets of inclusions—one of rutile and one of hematite—oriented in slightly different directions can cause a 12-rayed star.

Hematite inclusions cause asterism in black star sapphires. The sapphire’s color is actually yellow, green, or blue, but the inclusions make it appear dark brown or black.

The finest star is distinct, centered on the top of the stone, and visible from a reasonable distance, about arm’s length. The star’s quality should be the same when viewed from all directions.

Ideally, the rays should be uniform in strength, reach from girdle to girdle on the cabochon, and intersect at the top center of the stone. The best stars are straight, not fuzzy, wavy, or broken. The reflective stars should contrast strongly against the gemstone’s bodycolor. The star should also have elegant “movement.” This means that, as you rock the stone, the star should appear to move smoothly across the surface.

The best and most expensive star corundum is semi-transparent, with just enough silk to create a well-defined star. Too much silk can harm transparency and also lead to poor color, lowering the value of the stone considerably.
Sapphire Cut

Oval shapes with triangular and kite-shaped facets on the gem's crown (top portion) and parallel rectangular facets on the gem's pavilion (bottom portion) are very common for corundum of all colors. Photo: Robert Weldon/GIA. Courtesy: Lewis Allen
The shape of a rough sapphire crystal influences the finished stone’s shape and size. Rough sapphire’s most common crystal form is a barrel- or spindle-shaped hexagonal pyramid. To achieve the best overall color, maintain the best proportions, and retain the most weight possible, cutters focus on factors like color zoning, pleochroism, and the lightness or darkness of a crystal to best determine how to orient the gem during cutting.

These sapphires are miniature works of art that have been expertly cut into custom designs. – Photo: Robert Weldon/GIA. Courtesy: Mark Gronlund, Umatilla, Florida
Color zoning—areas of different colors in a stone—is a common sapphire characteristic. Blue sapphire often has angular zones of blue and lighter blue. To accommodate color zoning in some sapphires, cutters orient the concentrated color in a location that offers the best visible color in the cut stone.

In Sri Lankan sapphires, the color is often concentrated close to the surface of the crystal. If a cutter can orient the culet within the concentrated area of color, the stone will appear entirely blue in the face-up position.

Pleochroism refers to different bodycolors in different crystal viewing directions. Blue sapphires often have greenish blue and violetish blue pleochroism. It’s most desirable to orient the cut so the stone shows the violetish blue color when it is set in jewelry.

Besides coming in all colors, corundum also comes in all cutting styles. – Photo: Jeff Scovil. Courtesy: Ballerina Gems
Star Sapphire Cut
Star corundum must be cut as a cabochon to display asterism. A finished stone’s attractiveness depends on the star’s orientation and the cabochon’s symmetry, proportions, and finish.

The cabochon must have an appealing appearance, with the star properly centered when the gem rests on its base. The stone’s outline should be symmetrical.

For most stones, the dome should be fairly high—about two-thirds of the stone’s width—to focus the star sharply. If it’s too high, the phenomenon loses its graceful motion when the stone is tilted. Excessive height also makes the stone difficult to mount.

If the dome is cut too shallow, the star will be visible only from directly above. Black star sapphires, however, are prone to parallel breaks, so they’re usually cut very flat to reduce the risk of damage.

A stone should not have excess weight below the girdle that doesn’t contribute to the optical effect or reinforce color.
Sapphire Carat Weight
Blue sapphires can range in size anywhere from a few points to hundreds of carats, and large blue sapphires are more readily available than large rubies. However, most commercial-quality blue sapphires weigh less than 5.00 carats.

Fine-quality blue sapphires in larger sizes are rare, but they’re still more available than ruby. The incredible blue sapphire in the center of this ring weighs 18.79 carats. - Vagabonde Bleue Ring © 2011 Fabergé Ltd
Large commercial-quality blue sapphires are rare, but more available than large fine-quality ones. As a result, size makes more of a difference in the price of fine-quality sapphire.

Sapphires are available in all sizes, shapes, and colors. Photo: Robert Weldon/GIA, Dr. Eduard J. Gübelin Collection. @chapter:17 @chapter:0 @chapter:17


# Publication Year: 1993
# Title: Spring 1993 Gem News International
# Abstract: TUCSON ‘93
Diamonds
            Show Update
            Star-Cut Diamonds
Colored Stones
            Exceptional Iris Agates
            Baltic Amber
            Amethyst from Uruguay...
            . . . and Amethyst-Citrine from Bolivia
            Apatite from Brazil and Madagascar
            Uncommon Cat's-Eye Gems
            Gems with Natural Crystal Surfaces
            Beryls from the Ukraine
            Miscellaneous Notes on Emeralds
            Extraterrestrial Gem Materials
            Some Unusually Large Gems
            Jadeite from the Russian Federation
            Lapidary Art
            Opal from Canada
            Cultured Pearls from Tahiti, Australia, and China
            Natural Freshwater Pearls from Quebec
            "Peeling" Pearls
            Peridot from Ethiopia
            Red Quartz from Mexico
            Miscellaneous Fashioned Curiosities
            Transparent Rhodochrosite from Colorado
            Update on Rubies
            Miscellaneous Notes on Sapphires
            Spessartine Garnet from Africa
            Tourmaline from Paraiba, Brazil
            Parti-Colored Zoisites
Enhancements
            Apparatus for Fracture Filling Gems
Synthetics and Simulants
            Reconstructed Amber
            More "Pulled" Synthetic Materials Available
            Miscellaneous Emerald Simulants
Update
            1993 Burma Emporium
Announcements
G&G Wins Top Honor as Best Professional Journal

To view the full section, download the PDF above. @chapter:27 @chapter:0 @chapter:27


# Publication Year: -
# Title: Citrine Quality Factors
# Abstract: This award-winning 30.28-ct. super-trillion cut displays citrine’s highly valued, saturated orangy red color. – John Dyer, gem courtesy John Dyer & Co.

Color
Citrine’s attractive color, plus the durability and affordability it shares with most other quartzes, makes it the top-selling yellow-to-orange gem. A saturated yellow to reddish orange color free of brownish tints is prized in citrine, although in the contemporary market, citrine’s most popular shade is an earthy hue—a deep brownish or reddish orange.

	This group of rough and fashioned citrines exhibits the reddish orange colors enjoyed by consumers. - Dan Van Rossen, courtesy ICA

	Citrine’s colors range from pale brownish yellow shades like this one to intense reddish orange hues. - Robert Weldon
Since natural citrine is rare, most of the citrine on the market is the result of heat treatment, which causes some amethyst to change color from undesirable pale violet to attractive yellow. The amethyst’s original hue can determine the richness of the resulting citrine’s yellow.

	This fantasy-cut citrine started out as an amethyst. Its orange hues are the result of low-temperature heat treatment. - GIA & Tino Hammid

	Lime-colored citrine can result from heat treatment of smoky quartz. The gem’s designer used some frosted facets to highlight its trendy color. – Lydia Dyer,  gem courtesy John Dyer & Co
Clarity
Dealers look for citrines without color zoning or visible inclusions. Much of the faceted citrine in the market is eye-clean, meaning it lacks eye-visible inclusions.

	Most faceted citrine on the market has no eye-visible inclusions. - Robert Weldon

	Microscopic inclusions in citrine are usually not visible without high magnification.
Cut
Although citrine is available in standard shapes and sizes, in recent years many high-end jewelry designers and gem carvers have fashioned the warm yellow gem into unusual cuts for jewelry and carvings.

	A medley of oval-cut citrines in various sizes graces this elegant necklace. – GIA & Tino Hammid, courtesy a private collector

	Citrine carvings by gem designer Michael Dyber adorn a showcase at a Tucson gem show. - Eric Welch, courtesy Michael Dyber

	This golden cat is carved in citrine from Brazil. Its eyes are made of peridot and
	gold. - Robert Weldon
Carat Weight
Citrine crystals occur in a wide range of sizes, and citrines of up to 20 carats are readily available in jewelry.

	Award-winning gem designer John Dyer calls this gem’s cutting style the Regal Radiant Cut. It weighs 19.90 carats. – Lydia Dyer, gem courtesy John Dyer & Co.

	John Dyer’s Lime Citrine Reflections™ is a gem with an attractive lime green color, a fascinating designer cut, and a weight of 33.35 carats. – Lydia Dyer, gem courtesy of John Dyer & Co. @chapter:27 @chapter:0 @chapter:27


# Publication Year: 2002
# Title: Summer 2002 G&G Book Reviews
# Abstract: “Diamond Ring Buying Guide, 6th Ed.”
By Renée Newman, 160 pp., illus., publ. by International Jewelry Publications, Los Angeles, CA, 2002. US$17.95

“Tiaras: Past and Present”
By Geoffrey Munn, 128 pp., illus., publ. by V&A Publications, London, 2002. US$22.50

“Diamond Stories: Enduring Change on 47th Street”
By Renee Rose Shield, 234 pp., illus., publ. by Cornell University Press, Ithaca, NY, 2002. US$29.95

“Perlen”
By Elisabeth Strack, 696 pp., illus., publ. by Rühle-Diebener-Verlag, Stuttgart, Germany, 2000 (in German). –C66.00

“Diamonds: In the Heart of the Earth, in the Heart of Stars, at the Heart of Power”
By Hubert Bari and Violaine Sautter, Eds., 351 pp., illus., publ. by Vilo International, Éditions Adam Biro, Paris, 2001. US$60.00

“The Jewels of Jean Schlumberger”
By Chantal Bizot, Marie-Noël De Gary, and Évelyne Possémé, translated by Alexandra Bonfante- Warren, 157 pp., illus., publ. by Harry N. Abrams, New York, 2001. US$39.95

“Glossary of Obsolete Mineral Names”
By Peter Bayliss, 235 pp., publ. by The Mineralogical Record Inc., Tucson, AZ, 2000. US$32.00

“Modern Gemmology, SSEF Tutorials 1 & 2”
By SSEF Swiss Gemmological Institute, www.ssef.ch, Basel, Switzerland, 2001. Available in PC or Mac format. US $150 each/$250 for both

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


# Publication Year: -
# Title: Summer 1996 G&G Book Reviews
# Abstract: “The Art of Jewelry Design, Volume I”
By Maurice P. Galli in collaboration with Nina GiambeUi, 224 pp., illus. by Mamice P. Galli, Dominique Rivihre, and Fanfan Li, publ. by SchifferPublishing, Atglen, PA, 1994

“Collectable Reads: A Universal Aesthetic”
By Robert K. Liu, 256 pp., illus., publ. by Ornament, Inc., Vista, CA,
1995. US $49.95

To view the full section, download the PDF above. @chapter:20 @chapter:2 @chapter:20


# Publication Year: 1986
# Title: Summer 1986 G&G Lab Notes
# Abstract: Cobalt-Bearing Devitrified Glass
Glass with an Unusual Inclusion
Dyed and Sealed Lapis Lazuli
Assembled Opal Beads
Green Opal from Brazil
Cultured Pearls
Cat's-Eye Rutile
CobaIt-Blue Spinel
Turquoise with Simulated Matrix

To view the full section, download the PDF above. @chapter:18 @chapter:0 @chapter:18


# Publication Year: 2023
# Title: “Kaleidoscope” in Alexandrite
# Abstract: This 0.69 ct alexandrite showed a stellate structure due to cyclic crystal twinning and pleochroism, producing a kaleidoscope effect when rotated. These photomicrographs were taken with a single polarizer placed above the stone and a white diffuser below the stone to highlight the color. Photomicrographs by Makoto Miura; field of view 9.80 mm.
Recently, the author examined an interesting 0.69 ct alexandrite measuring 6.22 × 5.21 × 2.51 mm. This stone displayed a color change from greenish blue in fluorescent light to purple in incandescent light. Its trace element chemistry along with the presence of characteristic inclusions suggested a Russian origin.
Under the microscope, this alexandrite showed a unique stellate structure that was divided into six sections of purple, pink, and yellow color. Chrysoberyl occasionally shows a stellate structure due to cyclic crystal twinning (trilling), with triplets oriented at 120° to one another (e.g., K. Schmetzer, Russian Alexandrites, Schweizerbart Science Publishers, Stuttgart, Germany, 2010). Each section showed a different face-up color, and the colors were changed by rotating the stone. This observation suggested that the stone was cut from a cyclic twin rough crystal and the various colors were due to pleochroism, not color zoning. When rotating a single polarizer between the stone and objective lens (analyzer), opposite areas showed the same pleochroic colors (see above). This feature indicated that the alexandrite consisted of three penetration twins (again, see Schmetzer, 2010). The unique pleochroic colors caused by cyclic twinning were reminiscent of a kaleidoscope. @chapter:26 @chapter:0 @chapter:26


# Publication Year: -
# Title: Fall 2011 G&G Lab Notes
# Abstract: Unusually Large Clinohumite
	Black Diamond Colored by Strong Plastic Deformation
	Coated Black Diamond
	Coated Diamond with Spectroscopic Features of a Natural-Color Pink
	Colorless Untreated Diamonds with High Levels of Strain
	HPHT Treatment for Subtle Color Enhancement of Diamond
	An Interesting Luminescent Cleavage in Diamond
	A Large HPHT-Annealed Pink Diamond
	Gem-Quality CVD Synthetic Diamonds from Gemesis
	Treated Synthetic Diamonds with Pink Color Intensified by Fluorescence
	Cultured Pearls from Pteria Sterna with Plastic Bead Nuclei
	Large Conch Pearl
	Natural and Synthetic Green Sapphires with Similar Color but Remarkably Different Chromophores
	Unusual Be-Diffused Pink Sapphire . . . A Cautionary Note
	Unusually High Beryllium in Three Blue Sapphires

To view the full section, download the PDF above.

	DATA DEPOSITORY

Unusually Large Clinohumite - Additional Spectra
	October 24, 2011 @chapter:43 @chapter:1 @chapter:43


# Publication Year: 2005
# Title: Summer 2005 Gem News International
# Abstract: Colored Stones and Organic Materials
            Demantoid from Northern Pakistan
            Pyrope-Almandine from Ethiopia
            New Ruby and Pink Sapphire Deposit in the Lake Baringo Area, Kenya
            Faceted Orange and Brown Sunstone from India
Inclusions in Gems
            Staurolite in Kyanite from Brazil
            Obsidian with Spessartine Inclusions
            Fluorite Inclusions in Quartz from Madagascar
            Bismuthinite Inclusions in Rose Quartz from Madagascar
Synthetics and Simulants
            Yellow Hydrothermal Synthetic Sapphires Seen in India
Treatments
            Interesting Heated Citrine
            “Chocolate” Tahitian Cultured Pearls
            Lead Glass–Filled Rubies Appear in the Middle East
Conference Reports
            Gemmobasel 2005
Exhibits
            Cameos at the Met
            Diamonds in London

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


# Publication Year: -
# Title: Jeweler’s Goal: Unite Gem, Jewelry Industry in One of Mexico’s Largest Cities
# Abstract: Melissa Villarreal, a jewelry designer and GIA AJP who is working toward her Graduate Gemologist diploma, advocates immersive, ongoing learning. “Ask – don´t be afraid to get answers,” says Villarreal, pictured on a 2016 trip with the Mexico City and Monterrey-Mexico GIA Alumni Association chapters to the Sea of Cortez. “That is how you learn and become masterful at your craft, whether it’s sales, design or bench work. Never apologize for going in deep with your questions.” Photo by Guillermo Soberón Tirado

Melissa Villarreal’s vision for the fine jewelry industry in her hometown of Monterrey, Mexico – a city of 4.5 million people in the eastern state of Nuevo León – is simple, and bold: she’d like to help develop the nation’s third-most populous city into a thriving jewelry design and manufacturing hub.

That means doing away with the insular, “closed-off” approach that has dominated the region’s jewelry industry in the past and embracing a collaborative plan for success.

“I really believe in the power of community,” Villarreal says. “My idea of elevating the jewelry industry in Monterrey in the future involves an open-door, mature process of working together to create better industry opportunities for everyone. Jalisco (a nearby state) has a jewelry chamber of commerce, and I see no reason why we in Nuevo León shouldn’t have one, too.”

For Villarreal, the CEO of jewelry company Orofina and vice president of operations for her family’s Marco Antonio Jewelry, the first step in that direction was to create a local chapter of the GIA Alumni Association in 2015. The group’s growth and engagement has exploded in just a few short years, and the Monterrey-Mexico chapter is one of the most active in the international GIA Alumni Association network, according to Kate Donovan, alumni relations manager at GIA.

 “Having an open-door policy for former, current and potential GIA alumni allows us to reach people from all corners of the industry, from designers to new brands, to seasoned owners, bench jewelers and more,” she says. “We hold monthly meetings on different topics that relate to the jewelry industry and business itself. Getting a variety of topics covered by experts every month can be a challenge, but it is one that excites us and keeps the fire burning. We love a challenge because with it comes great growth and learning.”

“When you network, you learn from other people’s experiences and create a sense of community,” says Melissa Villarreal, founder of the GIA Alumni Association’s Monterrey-Mexico Chapter. “You also get to know other professionals who will work with you and get your business where it needs to be.” Villarreal, center, poses with her jeweler parents (on her right) and several members after a chapter meeting. Photo courtesy of Orofina
Villarreal’s investment in the success of the local jewelry industry, and her belief in the power of building a GIA network, came naturally.

As a third-generation jeweler, Villarreal grew up admiring her maternal grandmother, a jeweler who often traveled around the world and returned with “an exquisite selection” of gems. When Villarreal’s parents married, they, too, became jewelers. Her mother, Esthela, followed her own mother’s footsteps, and her father, Marco Antonio, took some classes at GIA.

“My father had the pleasure of meeting [former GIA president and “Father of Modern Gemology”] Richard T. Liddicoat, who graciously took him under his wing and showed him the ropes with dealers in New York City and California,” Villarreal says. “Some of them are still important to us, both in a personal and professional manner, to this day.”

Villarreal has fond memories of growing up around jewelry – playing with the tools at her parents’ store, taking family trips to trade shows – but didn’t choose it as her own path until later, after working in sales, design and fashion editorial for several years.

“I first learned about GIA from a very young age because of my father,” she says. “I even remember the GIA logo so well! I discovered that jewelry was my passion, too, and realized that I needed to have a strong education in jewelry and gemology if I was going to get seriously involved in the family business.”

This 22K gold necklace from Orofina features cube-shaped lapis lazuli beads. Photo courtesy of Orofina
Villarreal earned her Accredited Jewelry Professional diploma through GIA in 2006, then worked for a jewelry company in Houston, Texas for eight years. She and her husband, Fernando, returned to Monterrey in 2014, and she began working for her parents’ company, overseeing everything from design to sales and customer care.

“Working on my AJP online, with flexible hours and comprehensive materials, was fantastic,” she says.

In 2014, Villarreal also launched her own brand, Orofina, focused on creating jewelry that “highlights the natural beauty of the one who wears it.” Orofina is not “fast fashion,” she says, but represents “timeless elegance that can be passed on from one generation to the next.”

One of her early pieces – her first engagement ring, in fact – was purchased by a high-profile couple, football star Antonio Briseño of Portugal’s Feirense, and Mexican model and socialite Alethia Sada. The couple’s wedding, and Villarreal’s engagement ring, with a 1.71-ct round diamond center stone and diamond melee, earned quite a bit of press. The couple loved it, and it was a fulfilling moment for Villarreal.

“The best part of my career is the human connection, and having satisfied customers,” she says. “The fine jewelry industry is all about luxury, it’s not a necessity. These are costly decisions that must be treated with respect. When they thank you afterwards, you know you did your job right – and when they even share personal family moments where your jewelry was involved, that makes it even more special. You’re building a relationship.”

Orofina’s 14K yellow gold Rainbow ring includes citrine and Montana sapphires. Courtesy of Orofina. Photo by Maritere CR Photography
Villarreal was awarded a scholarship in 2015 to continue her GIA studies, and will begin the final stages of earning her GG diploma when she attends lab classes at the Carlsbad campus this fall.

She’s not alone: Villarreal has encouraged many attendees of the Monterrey chapter’s events to apply for GIA scholarships, and is proud to say that several of those people have also received them.

“A GIA education will allow them to keep growing in their preparation as jewelry professionals,” she says – as will the entire chapter.

“I strongly believe our efforts in the GIA Alumni Chapter are the stepping stone to a more open conversation between jewelers in Monterrey,” she says. “We can elevate it and lead it to becoming the design and manufacturing destination that I know it can be.” @chapter:45 @chapter:2 @chapter:45


# Publication Year: 2024
# Title: Intarsia Jewelry Box by Nicolai Medvedev and Susan Helmich
# Abstract: Left: The front of the “Blue Boy” chest features two wing-like “conk” wood opal slices from Nevada. Right: A 22K gold stingray adorns the top of the chest, guarding the contents within. Photo by Robert Weldon.
Opening day at the AGTA show was truly memorable with the premiere of “Treasure Chest II with Blue Boy” (see above, left), a joint collaboration between intarsia master Nicolai Medvedev and jewelry designer Susan Helmich. The exterior of the chest is adorned with Australian opal, Paraíba tourmaline from Brazil, diamonds, South African sugilite, Burmese maw-sit-sit, turquoise from the Sleeping Beauty mine (Arizona) and Nevada, gold-in-quartz from Australia and California, Utah dinosaur bone, 22K gold, and a matched pair of exquisite opal slices from Virgin Valley, Nevada. This type of Nevada opal is commonly referred to as “conk” wood, in which the cells of the original wood have been opalized. The slices featured on the front of the box came from the Bonhams opal and phenomenal gem auction in 2021.
The stingray “Blue Boy” on top was designed and hand carved by Helmich, created from 22K gold with Paraíba tourmaline and diamonds (see above, right). The interior is lined with burl wood veneer, with jasper inset into the lid, malachite (Bisbee, Arizona), and an 18K gold hinge. The chest, which took two years to complete, is the second in the series from Medvedev and Helmich. Their first chest featured an octopus. @chapter:28 @chapter:2 @chapter:28


# Publication Year: 2021
# Title: Apatite in Blue Sapphire
# Abstract: An apatite crystal is suspended over a cloud of rutile silk in this untreated star sapphire. Photomicrograph by E. Billie Hughes; field of view 6 mm.
One of the beauties of working with gemstones is that each time you peer into a stone, you get a glimpse of the universe held within. When we first examined the scene in a star sapphire (see above), we were delighted with the view. A feature that immediately stands out is the triangular crystal, which displays terraced growth features and iridescence on the surface when illuminated with a fiber-optic light. Analysis with micro Raman revealed that this crystal is apatite.
What makes the scene even more stunning is the way the crystal seems to float over a cloud of rutile silk. This same silk is what creates asterism in the stone.
While in this case the apatite crystal resides in a sapphire from Sri Lanka, apatite has also been reported in corundum from a variety of sources, including Afghanistan, Cambodia, Madagascar, Myanmar, Nigeria, Pakistan, Tanzania, Thailand, the United States, and Vietnam.
Apatite can be found not only in ruby and sapphire from different origins, but also in many other types of gems. In our laboratory, we have encountered apatite inclusions in emerald, spinel, and garnet.
Apatite is a relatively common mineral, so it is not surprising to find it so often as an inclusion. Although it may occur frequently, in this instance it is anything but mundane. @chapter:15 @chapter:0 @chapter:15


# Publication Year: -
# Title: Record Prices and Low Profits: The Bifurcated Diamond Trade
# Abstract: The Pink Star, a GIA-graded 59.60 carat Fancy Vivid pink diamond, sold for $83.2 million at a Sotheby’s auction Nov. 12, 2013 in Geneva. Photo courtesy of Sotheby’s. Update: According to media reports, Sotheby’s cancelled the sale of the Pink Star several months after the auction when the winning bidder was unable to complete the transaction.

	Two rare fancy colored diamonds set landmark price records last week at Geneva auctions. In the meantime, the more mundane side of the world diamond industry is still struggling with reductions in financing, tight liquidity and soft polished prices.

First the auctions: Christie’s sold a GIA-graded 14.82 carat Fancy Vivid orange diamond for $35.5 million.  At $2.4 million per carat, this is the highest-ever per-carat price for a gemstone at auction. The following day, a bidder paid $83.2 million ‒ the highest price ever paid for any gemstone anywhere ‒ for the 59.6 carat Pink Star, a Fancy Vivid pink diamond at Sotheby’s. This GIA-graded pink didn’t just beat the old record of $46 million (also a pink diamond), it demolished it. (Update: According to media reports, Sotheby’s cancelled the sale of the Pink Star several months after the auction when the winning bidder was unable to complete the transaction.)

	The Orange, a GIA-graded 14.82 carat Fancy Vivid orange diamond, sold for $35.5 million at a Christie’s auction Nov.11, 2013 in Geneva. Photo courtesy of Denis Hayoun Diode SA Geneva

	These were the top lots. Buyers, largely anonymous, also paid top prices for other lots: $4.6 million for the Cote D’Azure brooch containing a 58.29 carat Burmese sapphire and nearly $10 million for the Patino emerald and diamond necklace. The Pink Star helped Sotheby’s auction total set a new total record for a jewelry sale ‒ more than $199 million ‒ while Christie’s was $125 million.

	And, to provide context, there were also record prices in the auction houses’ fine art sales last week. A work by the Irish-born British artist Francis Bacon drew a top bid of $142 million ‒ the most money ever paid for a piece of art at auction. In the past two years, five paintings have changed hands at auction for more than $100 million each and a Cezanne reportedly sold for more than $250 million in a private sale.

	Luxury analysts say the market for such top pieces is driven by the ultra-wealthy in Western countries who are still concerned about uncertain financial markets and low interest rates. They view rare gems and art as a more certain investment, while, in other parts of the world, buyers use such assets as a hedge against political uncertainty.

Other Diamond News: Little of this translates to the market for diamonds and gemstones that sell for thousands (and hundreds) of dollars, instead of millions.

	Lack of profits and liquidity issues dominated the inaugural De Beers sight held in Botswana, November 12-15. The size of the sight was reportedly $470 million, though some companies may have received additional allocations. According to one report, prices were moderated slightly, about 2% on some goods, and the assortments were more closely in line with market needs.

	Despite this, some dealers did ‒ again ‒ leave goods on table they could not cut or resell profitably, though apparently not at the levels of the previous sights.

	The sight coincided with the first full tender auction of Botswana-mined rough by the Okavango Diamond Company, the auction subsidiary created by De Beers and the Botswana government to boost local manufacturers. Unlike the pilot sale where prices of some rough categories ran substantially higher than comparable sight goods, these results were reportedly in close alignment with De Beers set-sale prices. The banks’ sharp credit reductions of the past two months kept the bidding down at the tender sale.

	On an encouraging note, holiday jewelry sales in the U.S. are expected to increase about 4-5% over the 2012 total, according to most estimates. In unit terms, this increase should be a point or two higher because of the decline in gold and (to a much lesser extent) diamond prices during the year.

	For diamonds, retailer reports continue to head in diverging directions. Mid-priced stores and chains look to down-trade quality and size (lots of calls for “light sizes” have been reported), while higher-end retailers are in search of top makes.

	Indeed, one luxury market study reports that the Americas have surpassed China in terms of overall luxury goods spending, registering a 4% increase in 2013 compared with 2012, versus a 2.5% increase in China.

	A steady pace of store openings in second-tier cities in the U.S. has helped drive growth in the region, according to the 2013 Luxury Goods Worldwide Market study. This trend, along with an increasing number of Chinese tourists in Las Vegas and Los Angeles, has boosted growth. The report was commissioned by Altagamma, the Italian luxury goods manufacturers’ industry foundation. @chapter:37 @chapter:3 @chapter:37


# Publication Year: 2018
# Title: Nominal Type IaB Diamond with Detectable Uncompensated Boron
# Abstract: Figure 1. This 0.30 ct K-L diamond with faint brown color, mounted in an 18K gold prong setting, is a nominal type IaB diamond with detectable uncompensated boron. Photo by Wenqing Huang.

In recent years, nominal type IaAB and IIa diamonds with transient 2800 cm–1 FTIR absorption peaks arising from uncompensated boron produced under UV radiation have been reported (J. Li et al., “A diamond with a transient 2804 cm–1 absorption peak,” Journal of Gemmology, Vol. 35, 2016, pp. 248–252; Winter 2016 Lab Notes, pp. 412–413). The National Center of Supervision and Inspection on Quality of Gold and Silver Products recently examined a type IaB diamond that exhibited instantaneous 2803 cm–1 FTIR absorption shortly after exposure to an ultra-short-wave (< 230 nm) UV source.

Figure 2. DiamondView imaging shows blue fluorescence (left) and greenish blue phosphorescence (right) in the natural type IaB diamond. Images by Wenqing Huang.

Figure 3. The FTIR spectra reveal low concentrations of the hydrogen peak (3107 cm–1) and nitrogen impurities in the B aggregates (1174 cm–1) (blue line). Shortly after ultra-short-wave (< 230 nm) UV exposure, the transient boron-related absorption was recorded at 2803 cm–1 (red line). Spectra have been offset vertically for clarity.
Under ultra-short-wave UV excitation, the 0.30 ct K-L diamond with faint brown color, mounted in an 18K gold prong setting (figure 1), showed strong blue fluorescence and strong greenish blue phosphorescence that lasted for approximately eight seconds (figure 2). Infrared absorption spectroscopy showed low concentrations of the hydrogen-related peak (3107 cm–1) and nitrogen impurities in the B aggregates at 1174 cm–1 (figure 3), indicating a type IaB diamond (C.M. Breeding and J.E. Shigley, “The ‘type’ classification system of diamonds and its importance in gemology,” Summer 2009 G&G, pp. 96–111); prior to ultra-short-wave UV excitation, we were unable to detect the presence of the B center. No boron-related absorption was detected before UV radiation exposure, due to uncompensated B concentrations below the detection level of the FTIR spectrometer. But shortly after ultra-short-wave UV exposure, the transient boron-related absorption peak was recorded at 2803 cm–1 (again, see figure 3). Nitrogen-related peaks were detected at 415.7, 428.5, 439.0, and 452.4 nm using photoluminescence (PL) spectroscopy (figure 4); the peak at 415.7 nm belongs to the zero-phonon line (ZPL), while the others belong to its associated phonon replicas (A.M. Zaitsev, Optical Properties of Diamond: A Data Handbook, Springer-Verlag, Berlin, 2000). PL and FTIR spectra confirmed the diamond’s natural origin.

Figure 4. The photoluminescence spectrum of the sample excited at room temperature with a 405 nm laser reveals an N3 center with its zero-phonon line (ZPL) at 415.7 nm and its associated phonon replicas with peaks at 428.5, 439.0, and 452.4 nm.
The generally accepted mechanism for interpreting the phosphorescence in type IIb diamonds is donor-acceptor pair recombination processes involving boron and other defects (P.J. Dean, “Bound excitons and donor-acceptor pairs in natural and synthetic diamond,” Physical Review, Vol. 139, 1965, pp. A588–A602). Boron is deemed as the acceptor in the model, where the donor is believed to be nitrogen related, either as isolated nitrogen, aggregated nitrogen, or a plastic deformation–related defect (S. Eaton-Magaña and R. Lu, “Phosphorescence of type IIb diamonds,” Diamond and Related Materials, Vol. 20, 2011, pp. 983–989; E. Gaillou et al., “Boron in natural type IIb blue diamonds: Chemical and spectroscopic measurements,” American Mineralogist, Vol. 97, 2012, pp. 1–18). When almost all of the boron impurities received electrons from donors, almost no uncompensated boron (B0) was left behind, and therefore no boron-related absorption peaks were recorded. When the diamond was exposed to ultra-short-wave UV excitation, some of the compensated boron converted to an uncompensated state due to a charge transfer process between compensated boron and ionized donors, which could be recorded before the phosphorescence decayed. This mechanism is also suitable for interpreting the observed phenomenon of this specimen.
Natural diamonds with long-lasting phosphorescence under UV excitation are typically type IIb or chameleon diamonds (J.M. King et al., “Characterizing natural-color type IIb blue diamonds,” Winter 1998 G&G, pp. 246–268; T. Hainschwang et al., “A gemological study of a collection of chameleon diamonds,” Spring 2005 G&G, pp. 20–35). It is rare to find diamonds of other types, especially type IaB diamonds, showing this phenomenon. Finding a detectable, if temporary, B0 defect in a type IaB diamond is also unusual. @chapter:22 @chapter:1 @chapter:22


# Publication Year: -
# Title: An Archive of Excellence: The Richard T. Liddicoat Gemological Library Celebrates 25 Years
# Abstract: The Richard T. Liddicoat Gemological Library and Information Center at GIA's world headquarters, The Robert Mouawad Campus, in Carlsbad, California. Photo by GIA

                      700+ periodicals
1,800+ videos
57,000+ books
150,000+ photographs

The sheer magnitude of print, video and image resources available through the Richard T. Liddicoat Library and Information Center is astounding. From 31 different editions of philosopher Pliny's “Natural History” – including a copy published in 1496 – to George Frederick Kunz’s “Gems and Precious Stones of North America,” one of the most important works on gems, the library houses some of the rarest and most highly regarded books in gemological and jewelry history. What started humbly as a single bookcase has become the largest, most complete repository of its kind in the world and the first point of reference for those studying gems and jewelry.

GIA’s original library consisted of a handful of publications that GIA founder Robert Shipley loaned to students and staff. Over the years, the collection grew to include important books about gems and jewelry, trade journals and the latest gemological research, totaling 2,500 informally cataloged and stored volumes by 1980.

Richard T. Liddicoat, then-president of GIA, recognized the need and benefit of more professional attention to the Institute’s growing collection. He appointed Dona Dirlam, a diamond grader and former geology teacher, as librarian. Dirlam embarked on a decades-long effort to develop the library into the resource it is today. She began by opening the library to students and staff without an appointment, reorganizing and cataloguing the collection, and expanding the physical space and the staff.

“We needed more staff by the mid-1980s just to handle the growing number of phone calls requesting information,” said Dirlam. “The more you help people, the more they call back for help, and then tell other people.”

As more and more people outside the Institute learned about the indispensable resources available, the library continued to grow, and so did the importance of amassing a comprehensive collection.

GIA acquired the Sinkankas collection, which contains nearly every major work related to the study of gems and jewelry, in January 1988. Accumulated over 40 years by noted author and lapidary John Sinkankas and his wife, Marge, the collection added nearly 6,000 articles and 10,000 books, including works dating back to 1511 A.D., rare volumes and numerous editions in different languages. With the addition of the Sinkankas collection, the library became a resource unlike any other.

GIA held an inaugural celebration in August 1989 to formally dedicate the library to Liddicoat, the ‘Father of Modern Gemology,’ and to officially unveil the Sinkankas collection.

Nearly 300 guests attended the event, described by George Schuster in his 2003 book “Legacy of Leadership: A History of the Gemological Institute of America:”

August 21, 1989. It was a glittering summer night of champagne, laughter and honors, a black-tie evening of men in tuxedos and women in elegant gowns. It was a night important enough to attract hundreds of leading gem and jewelry industry figures to the Gemological Institute of America.

It was the night of the formal dedication of the Richard T. Liddicoat Gemological Library and Information Center, including the newly acquired, world-renowned Sinkankas collection.

It was the night of the official unveiling of what one writer called “the greatest collection of gemological literature ever assembled.”
…

During the official opening ceremony, guests heard firsthand accounts from Dirlam, Liddicoat, and Boyajian on the acquisition of the Sinkankas collection and what it meant to GIA and the gemological community. Another highlight was Sinkankas’s off-the-cuff comments on how he and Marge had created their personal library, including book-buying adventures in Europe, the Howes acquisition and his longtime relationship with GIA. Mayor James Conn presented [then-president] Bill Boyajian with a letter of commendation from the city of Santa Monica acknowledging GIA’s contribution to education in the community. At the end of the night, departing guests were handed reprints of Gems & Gemology’s Spring 1989 article on the Sinkankas collection.

Now, 25 years later, GIA’s library continues to grow and offer resources to the gem and jewelry industry, gem enthusiasts, students and the public. Library staff assisted more than 10,000 visitors, students and staff in 2013. It’s open to the public Monday through Friday, but you don’t have to be in California to take advantage of its resources. Experienced librarians also answer questions and offer reference for gem- and jewelry-related questions by email, mail, phone and fax, responding to more than 1,000 queries each year. You can also search the library catalog online and access all 80 years of Gems & Gemology, GIA's quarterly research journal, on the website.

For Dirlam, the goal of the library is simple.

“We want to make this library the archive of the international jewelry industry, and an important part of our mission to ensure the public trust in gems and jewelry.” @chapter:23 @chapter:2 @chapter:23


# Publication Year: 1994
# Title: Summer 1994 G&G Lab Notes
# Abstract: Diamond Laser Drill Holes or Natural Inclusions?
Diamond with Unusual Color Zoning
Trapiche Emerald from a New Locality
Jadeite with Metallic Inclusions
Round and Near-Round Freshwater Tissue-Nucleated Cultured Pearls
Glass-Coated Quartz
Synthetic Sapphire with a Small Star
Sapphires from Yogo Gulch, Montana
Dyed and Impregnated Turquoise
Faceted Vayrynenite

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


# Publication Year: 2015
# Title: Books: I Love Those Earrings: A Popular History from Ancient to Modern
# Abstract: By Jane Merrill with Chris Filstrup, 224 pp., hardcover, illus., publ. by Schiffer Publishing, Ltd., Atglen, PA, 2014. US$59.99.

              Earrings have proven to be a cultural touchpoint through the ages, treasures that transcend time and social value. Mythological characters depicted in Renaissance paintings and Hollywood legends like Catherine Deneuve wear them, as do Barbie dolls and pirates. In her inappropriately scaled and produced compendium, Jane Merrill traces the Western timeline of earring history. From the ancient Dacians to the modern era, she unwinds the cultural value of these portable jewels and adds a lively dash of pop culture.

Merrill’s is a wonderful viewpoint, one that offers a fresh translation of the history of jewelry. She pays special attention to the context and significance of earrings and other jewelry, often working from an art historian’s perspective. She covers an impressive expanse of time and geography with a collection of observations and stories arranged chronologically in an effort to humanize a subject that’s often associated with royalty and fame. Merrill mixes her own cultured experiences with those of the noble and storied to link ordinary people with celebrities and goddesses.

As virtuous as this inspired ambition may be, the message presented in the title and summary of the book does not play out in harmony. Merrill’s introductory invitation to “…raid the jewelry boxes of the prestigious and the more representative women of history…” suggests an exclusive, and visual, view of famous collections, a private and privileged peek into the boudoirs of queens and dressing rooms of movie stars. Disappointingly, this happens only once, with the inclusion of one painting of Jane Stanford’s auction collection, circa 1898.

By title and summary alone, the reader might also expect to find impressive photography of famous pairs of earrings, large in size and with great resolution. This is not the case. Most images are smaller in scale and arranged and captioned irregularly. Images that would support the text are not shown. Several stories would benefit from a series of timelines or maps, but these are not included.

Similarly, the format and layout are not representative of the sentiment and scholarship inside. While the percentage of white space on each page, the paper, and the printing quality promise vibrant, large-scale images and precise editing, this is not what is found within the pages. The background color of excerpts (light pink) is irritating at best, and worse, oversized images of earrings are often partially hidden by these dedicated boxes.

The most memorable musings and thought-provoking examinations in the book include the dynamic statements and comprehensive reflections throughout, such as the powerful call to recognize how meaningful earrings, like all pieces of jewelry, are. There’s plenty of evidence that they have been crafted, worn and celebrated the same way for thousands of years. Additionally, Merrill’s personal stories, those about her coauthor Chris Filstrup and the collection of prose and poetry at the end of the book—dedicated to lost earrings and lost loves—are the most memorable moments of the text. These high points and intriguing theories would have been better served by a revised title, theme, and size. @chapter:20 @chapter:2 @chapter:20


# Publication Year: 2000
# Title: Gemstone Enhancements and Detection in the 1990s
# Abstract: Gemstone enhancements and their disclosure became the most important gemological issue for the jewelry trade in the 1990s. Growing public awareness of treatments and the greater use of sophisticated technology to enhance the color and/or apparent clarity of gem materials brought to the forefront the need to maintain (or in some cases regain) the consumer confidence that is so vital to this industry. The treatments with the greatest impact were those that affected the gems that were commercially most important: heat and diffusion treatment of ruby and sapphire, “oiling” of emeralds, and fracture filling of diamonds. At the end of the decade, the decolorization of diamonds by high pressure and high temperature posed one of the greatest identification challenges ever faced by gemologists worldwide. Yet most other gem materials were also subjected to enhancements—ranging from traditional processes as with quench-crackled quartz to novel “impregnation” techniques such as the Zachery treatment of turquoise. This article discusses the treatments that were new or prominent during the ‘90s and suggests methods for their detection. @chapter:35 @chapter:1 @chapter:35


# Publication Year: -
# Title: Filigree Inlay Art: The Intangible Cultural Heritage of China
# Abstract: This filigree inlay brooch displays some very complicated filigree work on the insect’s head. Inlay work was used to mount the stone to the body. Photo by Eric Welch/GIA.

                      The art of filigree inlay, also called “fine gold art,” combines two craft skills. One is filigree, which includes such techniques as nipping, plaiting, jointing, piling, filling, and knitting, and uses gold or silver threads of different weights. The second component, inlay work, involves mounting the stones to the final product and carving or filing the precious metals. The craftsperson can use one or both skills when creating a piece.

	History of filigree inlay art
Filigree inlay art originated in the Warring States Period (475-221 BC). At the time, it was called “Jin Yin Cuo,” which involved painting gold and silver on the surface of bronze artworks. With the development of techniques for making thin gold and silver thread, which occurred around the Tang (618-907) and Song (960-1279) dynasties, filigree inlay art advanced in maturity.

The Ming dynasty (1368-1644) was the golden age of filigree inlay art. Many masterpieces were created and inherited. Following the Ming dynasty, filigree inlay art reached its peak in the Qing dynasty (1644-1911). Qing was the last dynasty in China’s history. However, it was ruled by the minority group “Man” for over 260 years.

The art form developed by inheriting essential elements from the previous dynasties and adding new elements over time. Many filigree inlay pieces seen in a private art museum run by the premium jade jewelry brand, Zhaoyi, are replicas of masterpieces from Ming and Qing dynasties.

For a long time, filigree inlay artwork was controlled and appreciated only by royal families and the imperial class. Ordinary people were able to afford some products, but were prohibited from owning pieces bearing certain themes like the dragon and phoenix. Only the royal class could own the highest-quality materials and designs.

Social catastrophe at the end of the Qing dynasty meant the imperial family could no longer hold its position and afford luxury items. Many master goldsmiths escaped the palace to open their own businesses. For a while, many small-scale filigree inlay art studios and workshops were concentrated in southern Beijing, which once had been an area full of all kinds of craftspeople.

	This pair of earrings is a replica of a Ming dynasty masterpiece. The earrings are 3-D replicas of lamps used in the Forbidden City. The lamps imitate pavilions with hexagonal profiles. Goldsmiths added seven spherical pendants to the pavilions. When the wearer moves, the pendants swing back and forth. Photo by Eric Welch/GIA.

	This is a replica of a Qing dynasty ring, once used as a gift from the mother-in-law to the new daughter-in-law, expressing wishes that she become a smart wife who benefits the family economically. By applying fine gold art, each small bead on the abacus can move freely. Photo by Eric Welch/GIA.
By the end of the 20th century, after the many social upheavals China had experienced over the previous 150 years, filigree inlay art was one of many cultural heritages that were fading away. Very few master goldsmiths were still able to work in this art form, and young people rarely devoted themselves to the diligence and hard work required. Another barrier came from the Cultural Revolution (1966-1976), when wearing or owning jewelry or simply being pretty was considered offensive.

The drafting, internationally, of the concept of Intangible Cultural Heritage in the early 2000s made it possible for filigree inlay art to be picked up and passed along to future generations. (The concept of Intangible Cultural Heritage encompasses practices, knowledge, and skills that are recognized as part of a country’s or community’s cultural heritage.)

	Collaboration between modern jewelry company and
	master goldsmith
Due to the outrageously high costs required for creating art pieces with filigree inlay art, very few people wanted to invest the money to start from scratch. At this critical moment, the collaboration between Zhaoyi and master goldsmith Bai Jingyi caught people’s attention. Before this collaboration, Master Bai had refused invitations from many jewelry companies due to conflicting interests. President Wang from Zhaoyi reassured Master Bai that making fast and major profit on filigree inlay art was not the company’s goal.

Zhaoyi, which began as a brand that specialized in jadeite, decided to contribute to the continuation of this almost-lost art. This time, Master Bai agreed and they established her studio about four years ago. Zhaoyi also supported Bai’s idea of developing the skills first and then creating some originally designed products.

	Zhaoyi, a famous premium jadeite brand, collaborated with Master Bai to create a filigree inlay art studio. The company uses profits from the jadeite business to support the haute couture filigree inlay art business. Photo by Pedro Padua/GIA.
For the past four years, Master Bai has spent most of her time teaching new artists and young apprentices, making replicas of famous historic pieces, and creating new designs using traditional skills. In Zhaoyi’s Beijing Xin Tian Di guild store, with its three-story layout, two levels are used to display filigree inlay art replicas and new designs. Located on the third floor is the only private filigree inlay art museum in Beijing. Numerous masterpieces from Bai’s studio are displayed there. As Master Bai and her colleagues are making progress on passing this craftsmanship along to the next generation, they are also working on creating new products to fit the high-end jewelry market in China.

	In her studio, Master Bai works on a piece of fine filigree art. Courtesy of Zhao Yi Xin Tiandi Co., Ltd.

	Master Bai Jingyi
After working as a goldsmith and designer in the filigree inlay industry for over 50 years, Bai expressed her deep love for this art style to some contributors.

Her family is made up of the “Man” minority, who formed China’s Qing dynasty. Influenced by her family tradition, she had fallen in love with painting when she was a little girl. Once, she dreamed of becoming a famous painter, but this dream did not come true due to different circumstances and life-changing opportunities she experienced later in her life.

	Master goldsmith and chief designer Master Jingyi Bai creates filigree inlay art and trains others to carry on its traditions. Courtesy of Zhao Yi Xin Tiandi Co., Ltd.
Other than painting, Bai was also very interested in pattern design. This provided a good basis for her entire design life. As a precious-metal major in school, she gained some of the needed knowledge and skills to make artworks like filigree inlay, enamel, etc., but she felt those skills were not enough to make her a successful master goldsmith and designer. She made the most progress after she started working in a real filigree inlay art factory and was trained by some older-generation master goldsmiths.

For the past 50 years, Bai has devoted herself to the tradition and development of filigree inlay art, receiving numerous honors and achievements. In 2008, the state council officially named filigree inlay art as the Intangible Cultural Heritage of China. Master Bai was selected to be the official Representative Inheritor at the same time. This honor and its responsibilities, plus her collaboration with Zhaoyi, brought her career to new heights.

With support from the company and her colleagues, Bai made many famous replicas of historic filigree inlay art pieces. One example is the “Six Dragon and Three Phoenix Crown.” She and her colleagues applied not just fine gold art to this piece. She also applied another almost-lost skill called “kingfisher feather skill.” The kingfisher is a beautiful bird with feathers on its back displaying very attractive and lively blue color. Old craftsmen pulled the feathers off a living bird and then mounted them in different jewelry pieces. It was an art used mostly by the Imperial family. In 2012, the “Six Dragon and Three Phoenix Crown” masterpiece was named the Beijing Arts and Crafts Treasure.

	Details were created using the ancient kingfisher feather skill on this “Six Dragon and Three Phoenix Crown” masterpiece. Photo by Eric Welch/GIA.
Now, Master Bai still works full time in her studio as the chief designer for Zhaoyi’s filigree inlay art haute couture services. She is pleased to see more and more young people joining her as apprentices to inherit this old but exquisite art. She expresses pride in them and tries her best to pass those skills on to the next generation.

	Master Bai still works full time at the studio, and also teaches students and apprentices. Courtesy of Zhao Yi Xin Tiandi Co., Ltd.

	The market for filigree inlay artwork
Although Master Bai and her group focus mainly on the filigree inlay art high-end market, she admits that there are two parts of the market as a whole. Many small-scale workshops around the country have limited investment levels and different interests. Their goal is not to inherit or pass the skills along to the next generation, but rather to make some quick money with relatively low-quality filigree inlay works, or add some filigree elements to other rapidly made products. These products dominate the souvenir market.

Master Bai originally thought that her high-end products would only be consumed by successful businessmen or older-generation high-ranking government officials. To her surprise, some young people are highly motivated to buy her creations as well. One of the studio’s first individually designed jewelry sets was purchased by a very young couple.

In terms of domestic and overseas markets, Master Bai does not see much difference between them because “going back to traditions” seems like a non-stop trend in the fashion world. She has noticed that China’s young people are paying more and more attention to their traditions. She enjoys seeing young girls wearing fashion outfits with traditional jewelry pieces inherited from their mothers or grandmothers. As for overseas consumers, in addition to paying attention to the style, they also focus on the craftsmanship of a piece. Overall, the market outlook for filigree inlay art is very bright.

	These newly designed modern filigree inlay art pieces are displayed in Zhaoyi’s art museum. Photo by Eric Welch/GIA.

	The future of filigree inlay art
As an Intangible Cultural Heritage of China, filigree inlay art has caught people’s attention and is being protected and passed along. Although there is hope in China of keeping this ancient art style and skill alive, there are some difficulties that can’t be avoided. First of all, there are fewer and fewer master goldsmiths. As time goes by, some skills will gradually be lost. More teachers are needed to pass knowledge and skills along to young people.

Secondly, more young apprentices are needed to inherit this art style. Some college graduates want to sit down and learn the skills, but to make sure there are enough people to inherit these skills and pass them along to the next generation, a larger inheritors’ pool is needed.

Last but not least, any type of art can be kept alive only when it can breathe on its own, which means it has to be alive in the real market, not just residing in some museums or appreciated by only a small group of people. Bai insists that even though the creation of replicas is necessary for picking up the almost-lost skills, she and her group will have to make modern designs that can be easily accepted by the current market and its consumers. This will result in keeping the art alive.

What Master Bai wants to tell young jewelry designers is that they need to absorb inspiration from both modern art and Chinese cultural traditions. As a big fan of western oil painting, Bai recommends that art students who want to be jewelry designers go overseas to learn modern art concepts and western artistic aspects. She also reminds them to not forget their own traditions, since that can distinguish them from others. As she says, the friction between western art and oriental tradition usually creates the most beautiful fireworks. @chapter:55 @chapter:2 @chapter:55


# Publication Year: 2017
# Title: Synthetic Moissanite Imitating Rough Diamond
# Abstract: Figure 1. A very light green 9.71 ct synthetic moissanite crystal, submitted to the Carlsbad laboratory as a rough diamond. Photo by Rebecca Tsang; field of view approximately 14 mm.

The Carlsbad laboratory recently examined a very light green 9.71 ct specimen (figure 1), measuring 11.79 × 9.69 × 11.61 mm, that was submitted as a rough diamond. The sample resembled a diamond octahedron, with surface growth features and a bright vitreous to subadamantine luster. Closer examination of its habit and surface features, along with gemological and advanced testing results, revealed it to be a synthetic moissanite.

The specimen was not a true octahedron, as is typical of a diamond crystal, but a rectangular bipyramid with 10 faces (eight triangular and two hexagonal side pinacoids on the girdle). The surface was dimpled, and two of the faces had deep striations resembling growth features in a rough diamond. Irregularly shaped and sub-hexagonal etch pits (figure 2), along with some dark brown residue, were also found on the surface. Due to the uneven surface, observation of internal features was limited to some small scattered pinpoint inclusions and a few etch tubes (figure 3). The surface also made it difficult to see any doubling effect or a doubly refractive reaction in the polariscope. Viewed in plane-polarized light, however, a large twinning plane crossed the crystal diagonally, bluish green on one side and colorless on the other. This dichroism served as proof of the stone’s doubly refractive nature, as opposed to singly refractive diamond. Standard gemological properties of the stone offered further evidence of its true identity, including an over-the-limit refractive index reading, a hydrostatic specific gravity (SG) of 3.23, very weak yellow fluorescence in both long-wave and short-wave UV, and a uniaxial optic figure. These properties and advanced testing results, including Fourier-transform infrared (FTIR) and Raman spectrometry, identified the specimen as synthetic moissanite. It is important to note that although natural moissanite exists, it is extremely rare and gem-quality material has never been found. Natural moissanite commonly occurs in fragmented pieces and in much smaller sizes (the largest known specimen measured 4.1 mm), often with a creamy white or red matrix (Summer 2014 GNI, pp. 160–161). That was not the case for this 9.71 ct synthetic moissanite.

Figure 2. Sub-hexagonal etch pits in synthetic moissanite are observed using differential interference contrast. Photo by Rebecca Tsang; field of view approximately 1.44 mm.

Figure 3. Etch tubes extended from surface etch pits and ended at the twinning plane. Photo by Rebecca Tsang; field of view approximately 2.30 mm.
Gemological and advanced testing are indispensable tools for revealing the true identity of gems, especially simulants and imitations with an appearance that can easily deceive the general public. While there is no evidence that this specimen was deliberately deceptive, gemological knowledge is important in preventing accidental and intentional acts of fraud and preserving the integrity of the trade. @chapter:43 @chapter:1 @chapter:43


# Publication Year: 2017
# Title: Colorful Chatoyant Glass
# Abstract: Starburst Stone is a colorful new devitrified glass, reminiscent of the product once marketed as Victoria Stone. Photo by Kevin Schumacher; courtesy of Australian Rough and Tumble.

This year at the Tucson gem shows, this author encountered an interesting new product of chatoyant devitrified glass (glass that has converted to a crystalline material) marketed as “Starburst Stone.” This material (see above) closely resembles the chatoyant glass known as Victoria Stone, which was developed in Japan by Dr. Satoyasu Iimori in the 1950s and produced for almost 40 years (http://victoriastone.sakura.ne.jp/JP-30-88-B.pdf).

John Bennett, in partnership with Artur Birkner (both based in Perth, Western Australia), began developing Starburst Stone in 2013, and this is the first year of commercially available production (approximately 100 kilograms). This devitrified glass is made from a chemical mixture that is cooled at a rate to facilitate nucleation and growth of dense networks of elongate lath-like crystals, and each batch of glass is colored by the addition of certain metals. Darker blues are achieved by adding cobalt, lighter blue by adding copper, and green by adding chromium to the glass mixture.

Standard gemological testing revealed properties consistent with manufactured glass. The RI was between 1.51 and 1.52 and varied slightly between the different colors tested. The average SG, measured hydrostatically, was 2.62. Raman analysis identified the devitrification product responsible for the chatoyancy as apatite, which was also responsible for the chatoyancy in the devitrified glass product known as Victoria stone.

Dark and light blue, green, and golden Starburst Stones are being manufactured, with additional colors in development. This new ornamental glass showing chatoyancy is a welcome addition to the gem trade. Those interested in the material once sold as Victoria Stone will certainly appreciate this very similar phenomenal glass product. @chapter:19 @chapter:0 @chapter:19


# Publication Year: 2016
# Title: Dyed Green Beryl
# Abstract: Figure 1. A green dye concentration in beryl was observed along fractures and confirmed by spectroscopic testing. Photo by HyeJin Jang-Green.

Emerald simulants and synthetic emeralds have often been submitted for testing to GIA (e.g., Spring 2001 Lab Notes, pp. 57–59). Recently, the New York laboratory examined a dyed green beryl that was intended to imitate natural emerald. The green octagonal step-cut stone, set in a yellow metal ring with near-colorless stones, initially appeared to be emerald.

The stone had a refractive index of 1.588–1.595 and fluoresced a very weak chalky yellow under long-wave UV radiation and a weak chalky yellow under short-wave UV. Microscopic examination revealed the obvious presence of a green dye concentration in numerous fractures (figure 1) and other natural beryl inclusions such as short needles, particles, and jagged fingerprint patterns. This dyed green material also enhanced the clarity of the stone.

In addition, dyed bands (~610 and 660 nm) were revealed in the visible spectrum by utilizing a high-resolution visible spectrometer (figure 2). The green color in this sample was caused by an organic dye rather than chromium or vanadium elements that give rise to a green color in natural emeralds. When the color was observed under a diffused light source, it became apparent that a near-colorless natural beryl was the starting material. This example shows the importance of spectroscopic testing to confirm the cause of an emerald’s color.

Figure 2. In the beryl’s Vis-NIR absorption spectrum, dye bands were observed at ~610
and 660 nm, while sharp Cr-related features were absent. @chapter:10 @chapter:0 @chapter:10


# Publication Year: 2014
# Title: Bumble Bee “Jasper” from Indonesia
# Abstract: Figure 1. This Bumble Bee “jasper,” measuring 32 × 54 mm, is a mixture of volcanic lava and sediment. Photo by Robert Weldon/GIA; courtesy of Robert E. Kane.

              At the Tucson Gem and Mineral Show, All in Vein (Quartzsite, Arizona) exhibited slabs and pairs of Bumble Bee “jasper,” which was sold elsewhere at the show as Eclipse “jasper.” The term jasper is a misnomer, as this vibrantly colored orange, yellow, and black material (figure 1) actually formed from a mixture of Indonesian volcano lava and sediment. A carbonate-rich rock first discovered on the island of Java during the 1990s, the material is soft, with a Mohs hardness of 5 or below. The porous rock is easily cut and polished, and most specimens are filled with Opticon (H. Serras-Herman, “Bumble Bee ‘jasper’: A colorful volcanic lapidary material,” Rock & Gem, Vol. 43, No. 8, pp. 26–29). @chapter:6 @chapter:0 @chapter:6


# Publication Year: -
# Title: Geo-Literary Society Explores Diamond Cut
# Abstract: At the February 2014 annual meeting of the Geo-Literary Society in Tucson, speakers Al Gilbertson (left) and Scott Sucher (right) discussed the evolution of diamond cutting.

                      The Geo-Literary Society held its annual meeting on Friday, Feb. 14 at the Tucson Convention Center. The event, which drew attendees from the Tucson Gem and Mineral Shows, featured presentations by Scott Sucher and Al Gilbertson in a session titled “The Evolution of Diamond Cutting.”

Sucher, president of The Stonecutter in Albuquerque, New Mexico, has created replicas of famous diamonds for more than 30 years. Gilbertson, a research associate at GIA in Carlsbad, California, has authored numerous articles on diamond cut and grading, as well as the 2007 book American Cut: The First 100 Years.

Sucher opened the session by chronicling the early history of diamond use, global trade patterns, and advances in cutting techniques and styles (see table). Using computer models, he compared the brilliance and fire of several early diamond cuts.

Table: Milestones in the early history of diamonds and diamond cutting

				ca. 1000 BC

				First archeological evidence of diamond as a cutting tool

				ca. 300 BC

				Early Indian manuscript discusses the qualities of diamond

				50 AD

				Pliny’s description of diamond use in engraving and jewelry

				1200s

				Development of the point cut (an octahedral crystal with polished faces); arrival of Indian diamonds in Europe’s royal inventories

				Early 1300s

				Establishment of cutting centers in Antwerp, Venice, and Amsterdam

				Mid 1300s

				Development of the table cut, a point cut with its top portion cut off to create a table-like surface

				Late 1300s

				Development of the single cut, a table cut with additional facets on the corners

				1400s

				Advent of the polishing wheel (scaife), and the discovery of cleaving as a faster way of shaping diamond

				1500s

				Improvements to the scaife, allowing polishing speeds of 1000 rpm

				1600s

				Development of the Mazarin, a double-cut brilliant

				1700s

				Development of the Old Mine cut, and the cutting of the famous Wittelsbach (prior to 1664) and French Blue (1671–1673) diamonds

Gilbertson picked up the story with the discovery of Brazilian diamond deposits around 1725, which ushered in a period of glittery excess among European elites. David Jeffries, whose 1750 treatise described the use of a handheld “prover” to measure cutting angles, coined the term “round brilliant” for a cut that contained 58 facets.

The discovery of massive diamond deposits in South Africa in 1867 changed the course of the industry, making these treasures available to a mass market. By 1870, there were 10,000 cutters in Europe. These artisans followed the shape of the original crystal and kept as much of the original weight as possible.

But the emphasis on weight retention was beginning to unravel thanks to Henry Morse, who had set up a cutting shop in Boston around 1860. Morse, who once said, “Shopping for diamonds by the carat is like buying a racehorse by the pound,” emphasized the cut of a stone and the brilliance that resulted. He invented a gauge to measure crown and pavilion angles, and devised his own set of best proportions. He also helped develop mechanical bruting, which increased the production of round-cut diamonds.

With turn-of-the-century improvements such as the circular saw, which made it easy to cut two diamonds from a rough crystal, the stage was set for the modern round brilliant. In 1919, Belgian engineer Marcel Tolkowsky published a landmark book titled Diamond Design, in which he asserted that the best-cut stones feature a 53% table, 59% total depth, and a knife-edged girdle. With some modifications to Tolkowsky’s proportions—an extended lower half, a larger table, and a closed-up culet—the round brilliant as we know it was established by 1950.

As Gilbertson pointed out, the breakthroughs in diamond cut planning and evaluation were just beginning. The Firescope viewer, developed in 1986, allowed the user to see a “Hearts and Arrows” pattern in a diamond cut to these “ideal” proportions. The Sarin scanner, introduced six years later, offered rapid, accurate proportion measurement, which led to the various cut grading services available today. Among other recent advances are inclusion-mapping software and high-speed laser cutting.

Following the presentation, Sucher invited the audience to view his faceted replicas of Cullinans I and II, the Koh-i-Noor, the Hope, and several other historical diamonds.

“Scott Sucher transported us to the early days of diamond cutting as we learned the first sources and tools,” said Dona Dirlam, the Geo-Literary Society’s secretary and the host of the session. “We saw how cutting styles evolved with improvements in the tools and an increase in the diamond supply. With each development, we saw this fascinating transformation through visual models.

“Al Gilbertson told us the largely unknown story of Henry Morse and chronicled the birth of the modern round brilliant,” Dirlam added. “As Al and Scott pointed out, today’s computer-optimized diamond cutting seems light-years removed from the earliest techniques.” @chapter:50 @chapter:3 @chapter:50


# Publication Year: 2018
# Title: Gem Characterization
# Abstract: Figure 1. Measuring about 7 cm across, this 404.2 ct rough from Angola’s Lulo mine is a good example of the irregular shape and surface texture associated with CLIPPIR diamonds. The unusual characteristics of diamonds like this one are the result of formation in a unique geological setting. Once cut, this rough yielded a 163.4 ct flawless D-color diamond. Photo by Jian Xin (Jae) Liao.

The Formation of Natural Type IIa and IIb Diamonds
Evan M. Smith and Wuyi Wang
GIA, New York
Many of the world’s largest and most valuable gem diamonds exhibit an unusual set of physical characteristics. For example, in addition to their conspicuously low nitrogen concentrations, diamonds such as the 3,106 ct Cullinan (type IIa) and the Hope (type IIb, boron bearing) tend to have very few or no inclusions, and in their rough state they are found as irregular shapes rather than as sharp octahedral crystals. It has long been suspected that type IIa and IIb diamonds form in a different way than most other diamonds.
Over the past two years, systematic investigation of both type IIa and IIb diamonds at GIA has revealed that they sometimes contain rare inclusions from unique geological origins. Examination of more than 130 inclusion-bearing samples has established recurring sets of inclusions that clearly show many of these diamonds originate in the sublithospheric mantle, much deeper in the earth than more common diamonds from the cratonic lithosphere. We now recognize that type IIa diamonds, or more specifically, diamonds with characteristics akin to the historic Cullinan diamond (dubbed CLIPPIR diamonds), are distinguished by the occurrence of iron-rich metallic inclusions. Less frequently, CLIPPIR diamonds also contain inclusions of majoritic garnet and former CaSiO3 perovskite that constrain the depth of formation to within 360–750 km. The inclusions suggest that CLIPPIR diamonds belong to a unique paragenesis with an intimate link to metallic iron in the deep mantle (Smith et al., 2016, 2017). Similarly, findings from type IIb diamonds also place them in a “superdeep” sublithospheric mantle setting, with inclusions of former CaSiO3 perovskite and other high-pressure minerals, although the iron-rich metallic inclusions are generally absent (Smith et al., 2018). Altogether, these findings show that high-quality type II gem diamonds are predominantly sourced from the sublithospheric mantle, a surprising result that has refuted the notion that all superdeep diamonds are small and non-gem quality. Valuable information about the composition and behavior of the deep mantle is cryptically recorded in these diamonds. CLIPPIR diamonds (figure 1) confirm that the deep mantle contains metallic iron, while type IIb diamonds suggest that boron and perhaps water can be carried from the earth’s surface down into the lower mantle by plate tectonic processes. In addition to being gemstones of great beauty, diamonds carry tremendous scientific value in their unique ability to convey information about the interior of our planet.
REFERENCES
Smith E.M., Shirey S.B., Nestola F., Bullock E.S., Wang J., Richardson S.H., Wang W. (2016) Large gem diamonds from metallic liquid in Earth’s deep mantle. Science, Vol. 354, No. 6318, pp. 1403–1405, http://dx.doi.org/10.1126/science.aal1303
Smith E.M., Shirey S.B., Wang W. (2017) The very deep origin of the world’s biggest diamonds. G&G, Vol. 53, No. 4, pp. 388–403, http://dx.doi.org/10.5741/GEMS.53.4.388
Smith E.M., Shirey S.B., Richardson S.H., Nestola F., Bullock E.S., Wang J., Wang W. (2018) Blue boron-bearing diamonds from Earth’s lower mantle. Nature, Vol. 560, No. 7716, pp. 84–87, http://dx.doi.org/10.1038/s41586-018-0334-5
Colored Diamonds: The Rarity and Beauty of Imperfection
Christopher M. Breeding
GIA, Carlsbad, California
Diamond is often romanticized as a symbol of purity and perfection, with values that exceed all other gemstones. However, even the most flawless and colorless natural diamonds have atomic-level imperfections. Somewhat ironically, the rarest and most valuable gem diamonds are those that contain abundant impurities or certain atomic defects that produce beautiful fancy colors such as red, blue, or green—stones that can sell for millions of dollars per carat.
Atomic defects can consist of impurities such as nitrogen or boron that substitute for carbon atoms in the diamond atomic structure (resulting in classifications such as type Ia, type Ib, type IIa, and type IIb) or missing or misaligned carbon atoms. Some defects are created during diamond growth, while others are generated over millions to billions of years as the diamond sits deep in the earth at high temperatures and pressures. Defects may be created when the diamond is rapidly transported to the earth’s surface or by interaction with radioactive fluids very near the earth’s surface. Each defect selectively absorbs different wavelengths of light to produce eye-visible colors. Absorptions from these color-producing defects (or color centers) are detected and identified using the gemological spectroscope or more sensitive absorption spectrometers such as Fourier-transform infrared (FTIR) or ultraviolet/visible/near-infrared (UV-Vis-NIR; figure 1). Some defects not only absorb light but also produce their own luminescence, called fluorescence. For example, the same defect that produces “cape” yellow diamonds also generates blue fluorescence when exposed to ultraviolet light. In some cases, the fluorescence generated by defects can be strong enough to affect the color of gem diamonds.

Figure 1. Visible-NIR spectra reveal the absorptions and corresponding atomic defects responsible for the color in gem diamonds.
With the exception of most natural white and black diamonds, where the color is a product of inclusions, colored diamonds owe their hues to either a single type of defect or a combination of several color centers. More than one type of defect can produce a particular color, however. Table 1 provides a list of the most common causes of color in diamond.

Subtle differences in atomic defects can drastically affect a diamond’s color. For example, isolated atoms of nitrogen impurities usually produce strong yellow color (“canary” yellow diamonds). If those individual nitrogen atoms occur together in pairs, no color is generated and the diamond is colorless. If instead the individual nitrogen atoms occur adjacent to missing carbon atoms (vacancies), the color tends to be pink to red. Rearrangement of diamond defects is the foundation of using treatments to change the color of diamond. Identification of treatments and separation of natural and synthetic diamond requires a thorough understanding of the atomic-level imperfections that give rise to diamond color and value.
Evaluating the Color and Nature of Diamonds Via EPR Spectroscopy
Haim Cohen1 and Sharon Ruthstein2
1Ariel University and Ben-Gurion University of the Negev, Israel
2Bar-Ilan University, Israel
Diamond characterization is carried out via a wide variety of gemological and chemical analyses. An important analytical tool for this purpose is spectroscopic characterization utilizing both absorption and emission measurements. The main techniques are UV-visible and infrared spectroscopy, though Raman as well as cathodoluminescence spectroscopy are also used.
We have used electron paramagnetic resonance (EPR) spectroscopy to compare the properties of treated colored diamonds to the pretreated stones. The colors studied were blue, orange, yellow, green, and pink. The EPR technique determines radicals (atoms with unpaired electrons) and is very sensitive, capable of measuring concentrations as low as ~1 × 10–17 radicals/cm3. The results, shown in table 1, indicate that all the carbon radicals determined are affected by adjacent nitrogen atoms, with the spectra showing a hyperfine structure attributed to the presence of nitrogen. The highest concentration of radicals and hyperfine structures is observed in pink and orange treated diamonds. The results concerning nitrogen concentration were correlated with the infrared spectra, which determine the absorption peaks of the diamonds as well as those of the nitrogen contamination in their crystal structure.

Quantitative Absorption Spectrum Reconstruction for Polished Diamond
Roman Serov (presented by Sergey Sivovolenko)
OctoNus Software, Moscow
Natural diamonds generally exhibit a very wide range of spectra. In polished stones, absorption along with proportions and size define perceived diamond color and thus beauty.
In rough diamonds, the quantitative absorption spectrum (the “reference spectrum” in the context of this article) can be measured using an optical spectrometer through a set of parallel windows polished on a stone, so the diamond can be considered a plane-parallel plate with known thickness.
Polished diamonds lack the parallel facets that might allow plane-parallel plate measurement. That is why polished diamond colorimetry uses one of two approaches that have certain limitations for objective color estimation:

Qualitative spectrum assessment with an integrating sphere. Suppose three diamonds are polished from a yellow rough with even coloration: a round (with short ray paths), a cushion (with high color uniformity and long ray paths), and a “bow tie” marquise (with both long and short ray path areas). The spectra captured from these three stones by an integrating sphere will be completely different because the ray paths are very different. However, the quantitative absorption spectrum will be the same for all three stones, since they are cut from the same evenly colored rough. Therefore, spectrum assessment with an integrating sphere has very limited accuracy and is practical for qualitative estimations only.
Analysis of multiple images of a diamond made by color RGB camera. This method has low spectral resolution defined by digital camera color rendering. The camera has a smaller color gamut than the human eye, so most fancy-color diamonds are outside the color-capturing range of a digital camera.

However, quantitative absorption data is very valuable for:

Color prediction and optimization for a new diamond after a recut process
Objective color assessment and description of a polished diamond

This paper presents a new technology based on spectral light-emitting diodes (LEDs) and high-quality ray tracing, which together allow the reconstruction of a quantitative absorption spectrum for a polished diamond. The approach can be used for any transparent polished diamond. The recent technology prototype has a resolution of 20–60 nm, which is practical for color assessment. Figure 1 (top) presents three photorealistic diamond images: A is based on the reconstructed absorption spectrum collected from a polished diamond, B uses the reference spectrum collected in the rough stage through a pair of parallel windows, and C uses the averaged reference spectrum. Figure 1 (bottom) shows both measured quantitative absorption and reconstructed absorption spectra.

Figure 1. Top: Photorealistic diamond images generated from the reconstructed absorption spectrum (A), the reference spectrum (B), and the averaged reference spectrum (C) of the same stone. Bottom: Quantitative and reconstructed absorption spectra.
This technology has the potential to ensure very close to objective color estimation for near-colorless and fancy-color polished diamonds. The reconstructed spectrum resolution can be enhanced to 10–15 nm in future devices. @chapter:44 @chapter:1 @chapter:44


# Publication Year: 1996
# Title: Summer 1996 Gem News International
# Abstract: Diamonds
            Diamond with a Fluorescent Phantom Crystal
            Tairus Synthetic Diamonds in Jewelry
Colored Stones
            Anorthosite Rock with Uvarovite Garnet "Speckles"
            Update on Porous Chrysocolla-Colored Chalcedony
            Chatoyant Clinochlore from Russia
            Cat's-Eye Diopside from Southern India
            Garnets from Mozambique
            Green-and-White Jadeite from Russia
            Visit to Myanma Gems Museum
            Variegated Translucent Jasper from Mexico
            An Unusual Morganite
            Scottish Pearls
            Rubies from Madagascar
            Sapphire Mining in Kanchanaburi
            Update on Tanzanite Mining
            "Golden" Tourmaline from Kenya
Treatments
            Novel Opal Doublets from Brazil
            Sapphires with "Induced" Stars
Synthetics and Simulants
            Manufactured Composite Material Imitating Jadeite
            "Drusy" Silicon, a Computer-Industry By-Product
            A Convincing Tanzanite Substitute
            "Tavalite," Cubic Zirconia Colored by an Optical Coating
Announcements
            Sixth Annual Cutting Edge Awards
            Gem-Related Exhibits at American Museums
            Special Synthetics Exhibit at the Sorbonne

To view the full section, download the PDF above. @chapter:16 @chapter:0 @chapter:16


# Publication Year: 2015
# Title: Garnets, Sapphires, Opals, and Tarnish on High-Purity Gold
# Abstract: Amethyst purple under fluorescent equivalent lighting, hot pink under incandescent…

	Welcome to the final Gems & Gemology of 2015. Colored gems—garnet, sapphire, and opal—are prominent in this issue. The Tanzanian garnet on our cover projects a rich, bold pink and demonstrates just how fine this material can be. It’s profiled in our lead article. The issue also offers insight into the origin of Montana’s alluvial sapphires, a gemological study of the historic Grand Sapphire, an investigation into tarnish spots on high-purity gold, and a field report on Australian opal.

	Our first paper—by three of GIA’s young research scientists, Ziyin “Nick” Sun, Aaron Palke, and Nathan Renfro—examines interesting “color-change” pyrope garnet from Tanzania. Under fluorescent-equivalent lighting, larger gems have the color of fine purple amethyst, while under incandescent they resemble hot pink tourmaline. The authors provide a comprehensive review of this material’s inclusions along with a quantitative analysis of its color under different lighting conditions.

	Alluvial sapphires from the U.S. state of Montana have long been celebrated for their kaleidoscope of colors, but so far no one has located these gems’ primary source rocks. In our second paper, a team of researchers led by Dr. J.C. “Hanco” Zwaan focuses on mineral inclusions and geochemistry to propose a metasomatic origin for Montana’s alluvial sapphires.

	Next, Dr. François Farges and his colleagues profile the fascinating history and gemology of Louis XIV’s 135.74 ct Grand Sapphire, which was added to the French crown jewels in 1669, around the same time as the fabled Tavernier Blue diamond. On the basis of microscopic examination and spectroscopy, the authors suggest that this magnificent blue sapphire originated in Sri Lanka’s gem fields.

	Our fourth paper investigates unsightly tarnish spots in high-purity (99.9% Au) gold jewelry. Dr. Taijin Lu and his team from the National Gems & Jewellery Technology Administrative Center (NGTC) in Beijing use a combination of advanced techniques to detect the presence of silver and sulfur in the tarnish spots. The authors recommend careful cleaning during the gold manufacturing process to eliminate the possibility of silver contamination.

	In June 2015, a GIA team consisting of Tao Hsu, Andrew Lucas, and Vincent Pardieu visited four important opal fields at the rugged fringes of Australia’s arid Great Artesian Basin: Lightning Ridge, Koroit, Yowah, and Quilpie. Their field report documents mining activity and the growing importance of the revenue and employment brought to these remote outback communities by “opal tourism.”

	As usual, you’ll find our regular Lab Notes and Gem News International sections along with the third installment of the Micro-World column. Our GNI section includes an update from field gemologist Vincent Pardieu on rubies from a new deposit in Zahamena National Park, Madagascar. There are also reports from the 2015 Geological Society of America (GSA) annual meeting in Baltimore, the first International Emerald Symposium in Bogotá, Colombia, and the 34th International Gemological Conference (IGC) in Vilnius, Lithuania.

	Finally, you’ll notice this issue includes a ballot card for the Dr. Edward J. Gübelin Most Valuable Article Award. We had a fantastic response to our 2014 reader ballot, so please do vote again for your favorite 2015 articles.

	Please enjoy the Winter issue! @chapter:2 @chapter:0 @chapter:2