Publication Year: 2013 Title: Titanium-Bearing Synthetic Alexandrite and Chrysoberyl Abstract: This Inamori synthetic cat's-eye alexandrite appears dark purple-red in incandescent light. Photo by Tino Hammid.

              Chrysoberyl, whether natural or synthetic, displays distinct pleochroism. The alexandrite variety is strongly trichroic and exhibits red/green color change. Phenomena such as chatoyancy and asterism can occur when oriented needle-like inclusions—mainly of rutile—are present. Chrysoberyl has the chemical formula BeAl2O4 and is orthorhombic. Its various colors are generally due to substitution of octahedrally coordinated Al3+ cations with chromophores such as the transition metal cations Cr3+ and Fe3+. Synthetic green chrysoberyl is known to sometimes have V3+ as a chromophore substituting for Al3+ in the crystal structure.

This work investigated Czochralski-grown synthetic reddish violet chrysoberyl, transparent alexandrite, and phenomenal alexandrite (both cat’s-eye and star) manufactured by Kyocera. This material entered the marketplace in the late 1980s with the Inamori brand name. The authors noticed unique pleochroism and spectroscopic features in the visible range in all of the samples except the transparent alexandrites—an indication of an unusual chromophore. Specifically, orange coloration influenced the hues observed in incandescent lighting in all three crystallographic directions, and absorption bands at around 500 nm were observed in these samples. It was noted that titanium, an element found in chrysoberyl generally in the form of rutile precipitates, was detectable in elevated concentrations in all of the samples with unusual pleochroism.

As mentioned above, rutile, or TiO2, is the common mineral inclusion that gives rise to asterism and chatoyency in chrysoberyl and other gem minerals, especially in the corundum varieties ruby and sapphire. In natural crystals of virtually all minerals, titanium is found as Ti4+, as Ti3+ is less stable (especially in the presence of iron) and readily oxidizes to Ti4+ (see R.G. Burns, “Intervalence transitions in mixed-valence minerals of iron and titanium,” Annual Review of Earth and Planetary Sciences, Vol. 9, 1981, pp. 345–383). However, titanium-doped synthetic laser crystals of both sapphire and chrysoberyl have been developed with titanium in the trivalent state, as this is the desired oxidation state to produce tunable lasing. In the case of Czochralski-grown titanium sapphire laser crystals, it is well documented that much of the material is grown in a virtually inert atmosphere, and post-growth annealing is conducted in a reducing atmosphere to convert the Ti4+ to Ti3+ (M. Kokta, “Process for enhancing Ti:Al2O3 tunable laser crystal fluorescence by annealing,” US Patent 4,587,035 A, May 6, 1986). Note: This contributor has observed that as-grown titanium sapphire crystals are generally milky and slightly purple in color before annealing. After annealing in a strongly reducing atmosphere such as hydrogen, the corundum crystals become clear and orangy red in color.

An investigation of the literature and comparison to spectroscopic data of the authors’ samples showed that the synthetic reddish violet chrysoberyl crystals and faceted gems and the phenomenal alexandrite samples do appear to have Ti3+ as a chromophore, which leads to the unusual pleochroism observed. In the case of the reddish violet samples, Ti3+ seems to be the predominant chromophore, as only traces of chromium, iron, vanadium, and manganese were detected. The cat’s-eye and star alexandrite samples appear to have a combination of Ti3+ and Cr3+ chromophores (with additional rutile precipitates being responsible for chatoyancy and asterism). The transparent alexandrites, meanwhile, appear to have a combination of Cr3+ and V3+ as chromophores. The detection of trace levels of Ti3+ in chrysoberyl strongly suggests a synthetic origin and possibly further heat treatment in a reducing atmosphere (to form reddish violet samples with predominant Ti3+ contents), and in an oxidizing atmosphere (to form rutile precipitates). @chapter:19


Publication Year: 2023 Title: Texas Topaz, Slovak Opal, a Beryl Inclusions Chart, and More Abstract: Welcome to the Winter 2023 edition of Gems & Gemology ! This issue brings an exciting conclusion to the volume year with three feature articles, a field report, a colorful new inclusions chart, and the return of the Colored Stones Unearthed column along with our other regular columns.
“…a prized gemstone from the United States: Texas topaz, sought after for its domestic provenance and rare natural blue color.”
Our first article explores a prized gemstone from the United States: Texas topaz, sought after for its domestic provenance and rare natural blue color. Dr. Roy Bassoo and coauthors begin with a historical account of topaz from Mason County, Texas, followed by discussion of its geologic origin, compositional characteristics, manufacture, and significance to the gem trade. In addition, the authors seek to provide a basis for determining geographic provenance.
Next, Dr. Karl Schmetzer and fellow researchers investigate a technique for setting cut garnets on glass objects, invented by Claudius vom Creutz of Nuremberg in the late sixteenth century. Examining two glass vessels at museums in Germany, the authors analyze the stones decorating the objects and the methods used to attach them.
Petrified tree fern from northeast China is the topic of our next article. A team led by Ying Yan reports on the gemological properties, chemical composition, and appearance of this material, which displays a beautiful pattern and is being used in intricate carvings in China.
Our fourth article, a field report from Dr. Peter Semrád, presents the revival of Slovak opal mining. It provides a brief history of mining in the area and details on geology and mineralogy, followed by coverage of recent mining activity, production, and marketing.
To close out our features, GIA researchers led by Nathan Renfro and John I. Koivula offer a captivating look at the internal features of beryl, with a foldout chart featuring 30 remarkable photomicrographs. Laminated versions of the chart, along with the six other inclusion charts in the series—emerald, sapphire, ruby, diamond, opal, and spinel—are available at store.gia.edu.
G&G’s regular columns continue to provide the latest gemological findings. Noteworthy updates from GIA laboratories are summarized in Lab Notes, including an HPHT-treated laboratory-grown diamond featuring dramatic color zoning, an antique Indian-style headdress decorated with seed pearls, and a rare faceted thomsonite. Micro-World showcases the inner landscapes of gemstones with striking hollandite crystals in a Brazilian amethyst, a stress halo resembling a butterfly in a natural diamond, a metal sulfide crystal suspended in a padparadscha sapphire, and more. Colored Stones Unearthed returns in this issue, covering the formation and mining of gemstones from sedimentary rocks. Finally, highlights from the Gem News International section include reports on pyritized triceratops fossils from South Dakota, training for artisanal diamond miners in Liberia, and a recent discovery of blue amblygonite-montebrasite from Rwanda.
We hope you enjoy the latest edition of Gems & Gemology ! @chapter:18


Publication Year: 2019 Title: E. Alan Jobbins (1923–2019) Abstract: E. Alan Jobbins
Alan, as he was known to his friends and colleagues, passed away February 2 at the age of 95. He was internationally respected for his lasting achievements in the fields of mineralogy and gemology. He started down his lifelong career path at the age of 13, when his geography professor showed him some attractive crystal specimens of the mineral mimetite from the Cumberland area of England. This immediately sparked his interest and led to a lifetime devoted to mineralogical and gemological studies, and his career appointment from 1950 to 1983 as curator of minerals and gemstones at the Institute of Geological Sciences in London. There he was responsible for organizing the extensive gemstone and mineral collection and exhibitions.
Over his 33 years at the museum, Alan conducted numerous important gemological and mineralogical research projects, such as a major study of East African garnets, research into the characteristics of synthetic opals, the discovery and description of the mineral magnesio-axinite, and the geological field study of the meteorite in Barwell Parish, England.
Alan’s work took him on many assignments for the United Nations and the British government. These included gemological and geological surveys of gem deposits in Brazil, Cambodia, Guyana, India, and Sri Lanka for the United Nations and the British Overseas Development Administration.
In the late 1960s, Alan set up a mineralogical and gemological training and research laboratory in Burma, guiding that country’s first gemologists to FGA diplomas. Some students went on to obtain doctorates at English universities. Alan led a study of Pailin ruby and sapphire deposits in Cambodia, resulting in a detailed monograph and important recommendations for improved recovery methods. He also spearheaded an assessment of diamond and opal deposits in PiauíState, Brazil, and a survey of the Sri Lankan gemstone industry in which he recommended improved mining methods and cutting techniques.
In 1988 and 1989, he initiated gemological training with new laboratory facilities at the China University of Geosciences in Wuhan. In the UK, his record includes 32 years as a gemological lecturer at the Sir John Cass College (now London Metropolitan University), 20 years as chief examiner for the Gemmological Association of Great Britain (now Gem-A) gemology examinations, and eight years as editor of The Journal of Gemmology (1985–1993). He was also president of Gem-A from 2004 to 2008, and vice president from 2009 until his death.
Alan held various posts throughout his career, including executive member of the International Gemmological Conference (IGC) and past president of the Society of Jewellery Historians. He was also part of the team that conducted the first comprehensive gemological examination of the British Crown Jewels from 1986 to 1989, which led to the publication of an important illustrated catalogue. Among Alan’s major literary contributions were very thorough revisions of B.W. Anderson’s Gem Testing and Robert Webster’s Gemmologists’ Compendium.
In 1984, Alan became a founding member of the ICA (International Colored Gemstone Association). In 2005 the Accredited Gemologists Association (AGA) awarded him its sixth annual Antonio C. Bonanno Award for Excellence in Gemology. He served as a member of G&G’s editorial review board from 1994 on.
In addition to gemology and mineralogy, our dear friend Alan was an avid bird-watcher, an explorer of churches and cathedrals, and a wine aficionado. He was a devoted and loving husband to his wife, Mary. In his honor I will carry the moniker he bestowed upon me many years ago, “Young Buzzard.” Alan passed away peacefully with Mary by his side. Rest in peace, dear friend. @chapter:1


Publication Year: 2013 Title: Diamond with Extremely Strong 578.9 nm Emission Center Abstract: Figure 1. This 4.72 ct Light blue type IIb diamond displayed some of the strongest dislocations ever observed in natural diamonds by GIA. This resulted in a hazy impression and a lower transparency than other type IIb diamonds. Photo by Jian Xin (Jae) Liao.

              Photoluminescence analysis at liquid-nitrogen temperatures and varying laser excitations has become increasingly important in diamond color origin testing. The 578.9 nm emission normally occurs with many other emission lines, and it is usually weak in natural type IIa and IIb diamonds. Meanwhile, the physical model of this optical center is unclear. The New York laboratory tested a very rare diamond that showed extremely strong 578.9 nm emission.

This 4.72 ct rectangular diamond (9.75 × 8.90 × 5.92 mm) had a color grade of Light blue and an even color distribution (figure 1). Infrared absorption spectroscopy analysis identified it as a type IIb diamond with a boron concentration of about 16 ppb. This stone showed very strong dislocations, resulting in a hazy impression and a lower degree of transparency than most type IIb diamonds. Microscopic observation revealed very strong linear graining and related high interference colors. The intensity of the dislocations was among the strongest ever observed in natural diamonds at a GIA laboratory.

The outstanding feature of this diamond was the extremely strong emission at 578.9 nm, with possible side bands at 586 and 593 nm (figure 2). No other emission line was detected in the visible light region, which is very unusual for a natural type IIa or IIb diamond. This feature was confirmed with 457 and 488 nm laser excitations. The exclusive occurrence of the 578.9 nm emission and the very strong lattice dislocations suggested that this emission was a dislocation-related optical center.

	Figure 2. The diamond showed extremely strong emission at 578.9 nm and its possible side bands at 586 and 593 nm. The exclusive occurrence of the 578.9 nm emission and the very strong lattice dislocations in this diamond suggested that the emission was a dislocation-related optical center. @chapter:11


Publication Year: 1995 Title: Winter 1995 G&G Book Reviews Abstract: “Photo Masters for Diamond Grading”
By Gary A. Roskin, 94 pp., illus., publ. by Gemworld International, Northbrook, IL, 1994. US$75.00

“A Sparkling Age, 17th Century Diamond Jewellery.”
223 pp., illus., pulbl. by the Diamantmuseum, Antwerp, Belgium, 1993, US$65.00

To view the full section, download the PDF above. @chapter:24


Publication Year: - Title: CVD-Grown Synthetic Diamonds, Part 2: Properties Abstract: These CVD synthetic diamonds produced by Gemesis Corp. range in size from 0.24 to 0.90 ct. Photo by Robert Weldon

Part 1 of this series provided a brief history of CVD synthetic diamonds.

The physical properties of CVD synthetic diamond fall well within the range for natural diamonds in terms of hardness, thermal conductivity, strength, and so forth. Therefore, CVD synthetics are as hard and durable as natural diamond and display the same brilliance and fire when cut as a gemstone. The optical properties can be varied over a wide range through the controlled introduction of impurities. For example, crystals can be made colorless to near-colorless by controlling the residual nitrogen level of the gas in the growth chamber. Blue diamonds can be created by adding boron to the gas, while pink, yellow, or other variations can be achieved using mixtures of gases, including high nitrogen concentrations. One particular advantage of CVD diamond production is that all crystals in a growth batch have the same color and clarity, making them easier to grade and match. And the color can be accurately repeated over an endless number of growth runs, ensuring reproducible color, clarity, and size, and an ongoing supply of high-quality synthetic diamonds for the gem industry. In addition, the ability to control size and purity will expand the uses of synthetic diamond beyond what is possible with natural diamonds, into new areas in optics, medical devices, electronics, and applications yet to be identified.

Other Properties
Colorless and near-colorless CVD synthetic diamonds are usually type IIa, while only 2% of natural gem diamonds are type IIa. Type IIa diamonds are characterized by high purity (low nitrogen) and transparency in specific parts of the ultraviolet and infrared optical spectrum. Numerous UV detection instruments on the market can provide the first indication of a possible CVD synthetic. Obviously, additional tests would then be required to confirm whether the sample is CVD-grown or natural. If the gem is not IIa, it is most certainly natural. There will be additional discussion about non-IIa synthetic diamonds and the properties of blue, pink, yellow, and other colors in a future article.

A common question in the diamond trade and among consumers is whether CVD synthetics will eventually be manufactured so inexpensively that the value of natural diamonds endangered. The answer to that question is no. While CVD growth will become more efficient due to scale and manufacturing experience, several factors will only become more expensive with time and inflation. First, the cost of cutting and polishing CVD products is essentially the same as for natural diamond, and highly skilled artisans will still be needed to create beautiful goods. A second factor is that the electricity required to produce one carat of diamond does not scale significantly with the number of seeds or chamber size. Electricity is a major cost, one that is expected to continue rising in the future, and there is little room for cost reduction here. A third cost is that of producing seeds. This is a significant overhead, and it is unlikely that an inexpensive alternative for a diamond seed will ever be found.

A more persistent threat to integrity and pricing in the diamond industry will be the misrepresentation of cubic zirconia and other imitation materials as “synthetic diamond.” While there are adequate tests for these imitations, they are not readily available for purchases made on the web.

Conclusions
CVD synthetics can be grown in a range of colors and sizes, with high clarity. The gemstones produced are as beautiful and durable as natural diamond, and they are expected to fill an important market niche in the near future. It is important to note that GIA has the ability to detect and grade CVD synthetics, which will continue to protect buyers and the integrity of the diamond industry.

In the next installment of this series, we will discuss detection of CVD synthetic diamonds. @chapter:15


Publication Year: 1995 Title: Summer 1995 Gem News International Abstract: Diamonds
            More Firms Processing Fracture-Filled Diamonds
            Synthetic Diamonds Misrepresented as Canadian Rough
Colored Stones
            Large Aquamarines from Nigeria
            Clinochlore and Other Rare Collector Stones from the Former Soviet Union
            Other Unusual Gems Seen at Tucson
            Phenomenal Feldspars from India
            Parti-Colored Fluorite from Brazil
            Unusual Opal Carvings
            Update on Opal from Ethiopia
            Sapphires from Madagascar
            Sapphires and Other Gems from Tanzania
            Spessartine Garnet from Namibia
Synthetics and Simulants
            Amber Simulant: Natural Resin in Plastic
            Update on "Recrystallized" Corundum
            Laser-Inscribed Synthetic Colored Stones
            Partially Devitrified Glass Imitation of Jadeite
            Iridescent Hematite Simulant
            Kyocera Plastic-Impregnated Synthetic Opals
            Platinum Alloy as an Ornamental Material
Instrumentation
            New Gemological Spectrometer at Tucson

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


Publication Year: - Title: Moonstone Care and Cleaning Guide Abstract: While requiring care to avoid damage, moonstone lends an almost magical sheen to jewelry. - Courtesy Richard Krementz Gemstones

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

Moonstone falls between 6 and 6.5 on the Mohs scale. It also has poor toughness.

	Moonstone ranks 6 to 6.5 on the Mohs scale.
Moonstone has two cleavage directions, a trait it shares with the other members of the feldspar family of minerals. Cleavage is a direction of atomic weakness that makes a crystal more prone to breaking. Cleavage can affect durability, so manufacturers usually set moonstone into pendants, earrings, and pins rather than rings, which are more likely to receive knocks and bumps.

	Due to a property called cleavage, a hard blow can break a moonstone.
Stability
High heat or sudden temperature change can cause breaks in moonstone. It is stable to light but is harmed by exposure to hydrofluoric acid.

Cleaning
Warm soapy water is the only recommended substance for cleaning moonstones. Ultrasonic and steam cleaners are never recommended. @chapter:23


Publication Year: 2017 Title: Magnificent Sapphires from Montana’s Rock Creek Mine Abstract: Figure 1. This 12.61 ct blue sapphire and 7.90 ct orange sapphire recently mined by Potentate show that large material still comes out of Rock Creek, Montana. Photo by Eric Welch/GIA, courtesy of Potentate Mining.

Potentate Mining marketing director Warren Boyd presented two magnificent sapphires (figure 1) and a suite of fancy sapphires extracted from the company’s Rock Creek operation in Montana in 2016. He also updated the authors on this past mining season.

The larger of the two stones is the 12.61 ct blue sapphire, one of the largest of its kind from Montana. It was faceted from a 6.37 g rough that had been heated. The rough showed strong blue color before heating but had a core with heavy silk inclusions. Heating dissolved the silk and enhanced the blue color. The 7.9 ct orange oval is the largest of this color ever recovered from Montana, to Boyd’s knowledge. This stone was faceted from a 5.2 g rough of pale greenish color with a dark brownish core. While the rough was of very low transparency, the results of heating were better than expected. The heated rough showed a royal blue rim surrounding a bright orange core. Both stones were faceted by Jeff Hapeman (Earth’s Treasury, Westtown, Pennsylvania).

	Warren Boyd – Potentate Mining LLC

In this interview, Mr. Boyd delivers an update on Potentate Mining’s production of Montana sapphire and the importance of maintaining consistent levels of production for supply to the jewelry industry. He also provides background on some remarkable sapphires: fashioned 7.90 ct orange and 12.61 ct blue sapphires and a pristine pale blue 59.50 ct crystal, the largest transparent crystal the company has recovered to date.
Most of the Rock Creek sapphire is small, and larger stones with spectacular colors are very rare. Because the bulk of the production comes out of the ground with greenish pastel colors, natural stones with bright colors are also very valuable. Boyd and his clients from Americut showed us a suite of natural fancy sapphires (figure 2) recovered in 2016. The company had produced sapphire rough from its Rock Creek deposit for two consecutive mining seasons and gradually built up a large inventory. Potentate is not planning to increase production but to keep it stable in the near future. The company installed a new water clarifier in its washing plant at Eureka Gulch, which recycles the water used in ore washing. The company will keep its focus on building inventory and bridging the gap between supply and demand.

Figure 2. As displayed by these rough and cut sapphires, Potentate’s sapphire
production includes a wide variety of colors. Photo by Eric Welch/GIA, courtesy of
Potentate Mining. @chapter:20


Publication Year: 2018 Title: Strong Fluorescence in B-Jade Impregnated with Wax Abstract: Figure 1. Left: The wax-impregnated jadeite jade bangle submitted for identification. Right: The bangle exhibited strong bluish fluorescence under long-wave UV radiation. Photos by Lai Tai-An Gem Lab.
Fine-quality jadeite jade is known for its high value in the market. “A,” “B,” and “C” jade are classifications applied to jadeite that relate to various states of enhancement. However, many in the market may not understand the real meaning of the terms. A-jade shows no indications of having undergone modification through the impregnation with colorless or near-colorless wax, resin, or any other agent. When the material has been treated through bleaching and the impregnation with colorless or near-colorless wax, resin, or any other agent, it is described as B-jade. When it shows indications of having fissures or fractures filled with a color agent, it is defined as C-jade. B and C areas may exist in the same specimen; this is described as B+C-jade. A bangle submitted to the Lai Tai-An Gem Laboratory (figure 1, left) illustrates the common misconception that B jade is only impregnated by resin. In fact, wax-impregnated jadeite jade is also defined as B-jade.
The client who submitted the bangle believed it was resin-impregnated jadeite owing to its suspiciously strong fluorescence reaction. The item possessed an uneven green and white color with a greasy luster and weighed 277.14 ct. It measured approximately 76 mm with a thickness of 9–10 mm. A refractive index (RI) reading of 1.66 was obtained from five random spots on the bangle, and a specific gravity (SG) of 3.34 was also recorded. The most interesting feature was an unusually strong reaction under long-wave UV (figure 1, right), indicating it was probably treated and should be examined with more care. This material was determined to be jadeite jade when subsequently tested by Fourier-transform infrared (FTIR) spectroscopy, but the FTIR results also revealed some features other than the jadeite-related peaks.

Figure 2. Microscopic observation revealed obvious acid etching marks, coarse pits, and cobweb-like surface fissures. Photo by Lai Tai-An Gem Lab; field of view 4.6 mm.
FTIR analysis confirmed that the jadeite bangle was heavily impregnated with wax. The absorption peaks at 2850, 2920, and 2965 cm–1 differed from those expected in resin-impregnated material—which usually exhibits peaks at 3061 and 3040 cm–1—and they were intense and sharp enough to indicate that a significant quantity of wax had been applied. Microscopic examination revealed obvious acid etching marks, coarse pits, and cobweb-like surface fissures (figure 2). Wax residues were also found within pits and fissures when poked. Additional unseen wax was apparently within the structure according to the wax pattern revealed by FTIR analysis, typical for wax-impregnated B-type jadeite, which clearly explains the strong reaction under long-wave UV.
While the term B-jade is meant to be applied to wax- and/or resin-impregnated material (Laboratory Manual Harmonisation Committee Information Sheet #11, http://www.lmhc-gemology.org/pdfs/IS11_20111215.pdf), many traders misleadingly describe B-type jadeite jade as resin-impregnated only. This leads the unsuspecting buyer to believe that wax-impregnated jadeite jade is A-jade. This case clearly shows that those dealing in jadeite should be aware of the differences between resin- and wax-impregnated materials, even though both are considered B-jade, and understand that confusion may arise if items are not carefully checked. @chapter:37


Publication Year: - Title: Iolite Quality Factors Abstract: The cutter took full advantage of this iolite’s color and transparency, fashioning it into a uniquely carved gem, ready for use in jewelry. – Lydia Dyer, Gem courtesy John Dyer & Co.

                      Affordable and attractive, iolite can be used in many types of jewelry. It’s sometimes found in large sizes and beautiful, intense colors that satisfy even the most discriminating colored gemstone connoisseur.

Color
Iolite possesses two distinctive features—a beautiful, violetish blue through slightly violetish blue hue derived from iron and a striking, eye-visible pleochroism. Its pleochroic colors differ with its bodycolor. Iolites that appear violet display light violet, dark violet, and yellow-brown pleochroic colors.  Bluish iolites display colorless to yellow, blue-gray, and dark violet pleochroic colors. From some angles, then, a bluish iolite can actually appear completely colorless or yellow, and a violetish iolite can look brown. Some gems can look grayish or nearly colorless.

	This attractive iolite was skillfully cut to show its best color face-up.
Clarity
Iolite is commonly transparent, with relatively few inclusions. It can be found in all shapes and has even been carved to beautiful effect.

Iolite can contain inclusions that cause various phenomena. Occasionally, iolites with long, parallel, tubular inclusions are found. When the cut is oriented properly, these stones yield cat’s-eye gems.

Iolite containing numerous metallic, plate-like inclusions can be cut to display a sparkly effect known as aventurescence. When the platelets are brownish or reddish in color, the gem might be marketed as “bloodshot” iolite.

	The brownish and reddish inclusions make this a “bloodshot” iolite.
Cut
Because it is commonly transparent with relatively few inclusions, iolite is most often faceted. However, iolites can be cut into cabochons or carvings as well. They are frequently seen as beads, especially when the material is of somewhat lower quality.

Carat Weight
The size range for a fashioned iolite is anywhere from 1 to 10 carats, but fine iolites over five carats are rare. @chapter:23


Publication Year: - Title: Ruby History and Lore Abstract: To commemorate the 50th anniversary of The Wizard of Oz, Harry Winston created real ruby slippers set with 4,600 rubies. - Courtesy Harry Winston

                      Red is the color of our most intense emotions—love and anger, passion and fury. It’s associated with objects of power and desire—like fast cars and red roses. Early cultures treasured rubies for their similarity to the redness of the blood that flowed through their veins, and believed that rubies held the power of life.

Ruby is one of the most historically significant colored stones. Rubies are mentioned four times in the Bible, in association with attributes like beauty and wisdom. In the ancient language of Sanskrit, ruby is called ratnaraj, or “king of precious stones.”

In the first century AD, the Roman scholar Pliny included rubies in his Natural History, describing their hardness and density. Ancient Hindus believed that those who offered fine rubies to the god Krishna were granted rebirth as emperors.

Hindus divided ruby into four castes, calling the true Oriental ruby a Brahmin. Someone in possession of a Brahmin was believed to have the advantage of perfect safety.

Ruby has accumulated a host of legends over the centuries. People in India believed that rubies enabled their owners to live in peace with their enemies. In Burma (a ruby source since at least 600 AD—now called Myanmar), warriors possessed rubies to make them invincible in battle. However, it wasn’t enough to just wear the rubies. They had to insert them into their flesh and make them part of their bodies.

The name ruby comes from the Latin word ruber, which means “red.” The glowing red of ruby suggested an inextinguishable flame burning in the stone, even shining through clothing and able to boil water.

Ruby has been called the most precious of the 12 stones created by God.

Ruby retained its importance with the birth of the western world and became one of the most sought-after gems of European royalty and the upper classes. Many medieval Europeans wore rubies to guarantee health, wealth, wisdom, and success in love.

Desire for ruby is just as great today as it always has been. As a symbol of passion, ruby makes an ideal romantic gift. Consumers are drawn to the lush color because it also signifies wealth and success. @chapter:25


Publication Year: - Title: Bridges Family and Tsavorite Update Abstract: Bruce BridgesBridges Tsavorite

Interview with Bruce Bridges, Bridges Tsavorite
There are moments in GIA’s compelling interview with Bruce Bridges that the son of legendary gem pioneer Campbell Bridges speaks optimistically about finally getting some justice in the brutal killing of his father in August 2009.  Eight suspects, who were named, photographed and eye-witnessed at the time of the crime, were arrested almost immediately. Yet the case has dragged on for more than three years, not only leaving the Bridges family in torment, but the Kenyan mining economy in a state of suspended animation.

Bridges reflects on his father’s life and work, which led him from his native Scotland to Africa, where he made his mark in the gem world with the discovery of tsavorite. For all the fame the discovery brought him, it seemed cursed from the start. His first discovery in Tanzania in 1969 went nowhere when the country refused to grant him a mining permit. His second discovery in Kenya in 1971 demanded eternal vigilance from poachers, thus giving his mine the name Scorpion after the poisonous creatures he would leave to guard it. Ultimately tsavorite led to his death at the hands of thuggish competitors.

In the interview Bridges also talks about the finer points of tsavorite—its shape and color—and describes the grading system used. He also discusses their use of master stones in grading and gives insight into tsavorite quality.

A truly special treat in the following video is the first-time unveiling of a brilliant umbalite specimen with tremendous sentimental value. When they were cleaning out his father’s belongings, Bruce tells us, they came upon a camera film canister labeled “2 pcs rgh.”  When they opened it, they found the umbalite rough. They had it cut and polished and here it’s on full display before our GIA camera. @chapter:18


Publication Year: 2016 Title: GILC 2016 Abstract: The International Colored Gemstone Association (ICA) held its annual Gemstone Industry & Laboratory Conference on February 1 during the Tucson shows. Invited participants included jewelry trade association leaders, laboratory representatives, academic institutions, and ICA members. This year, other industry members were welcomed into the afternoon open discussion session.

Lore Kiefert (Gübelin Gem Lab, Lucerne, Switzerland), presenting on behalf of her colleague Daniel Nyfeler, spoke on age determination by radiogenic isotopes. Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) has enabled the Gübelin Lab to use radiometric dating to test inclusions at or near the surface of materials such as corundum and emerald, which do not have radioactive atoms. When traditional methods such as observation of inclusions and growth structure and trace element analysis lead to more than one possible country of origin, radiometric dating can furnish the decisive data. U/Pb decay in zircon has been well documented as a means to establish an approximate timeline for known sapphire and emerald populations. The corundum timeline established the oldest population as African, with an age of 450–650 million years (Ma), and the youngest as Colombian, at 10 Ma. Emerald formation ranged from South Africa at 2900 Ma to Colombia at 65–35 Ma. This method is limited when the gemstone presents no analyzable inclusions or has been treated.

James Shigley (GIA, Carlsbad) presented the Institute’s latest research findings. GIA’s work with color analysis has its foundation in observation and color grading of colored diamonds. Dr. Shigley noted that the visible spectrum is not the only cause of color; in fact, the face-up appearance is influenced by about 15 factors, including the emission spectrum of the light source, the absorption spectrum of the stone, and the color sensitivity of the eye. Since humans are more adept at distinguishing differences than similarities, the use of master stones and bracketing between pairs is well suited for visual grading. GIA uses instrumentation to supplement visual grading in face-down evaluation of round near-colorless D to Z diamonds; however, fancy-color diamonds are graded face up. GIA has been working on analytical tools that can “detect” color in the same way that the human eye processes it.

Bruce Bridges (Tsavorite USA, Inc.) asked whether gems can be reliably traced from the source to the consumer. Today’s consumer wants to know where products come from and how their manufacture affects both the environment and workers. Vertically integrated companies can promote traceability and control over ethical sourcing, but the business model cannot be applied to the small-scale operations that characterize most of the industry. Bridges outlined the convoluted path from small-scale or individual miner through a series of brokers to cutting and the “end user” market, where it may go through another series of dealers before reaching a consumer. Most colored stone sources are overwhelmingly alluvial or placer deposits in remote areas, making them difficult to centralize. Traceability is even challenging at the mine, where it is not uncommon for material from a different location to be sold without disclosure. Traceability from cutting centers can improve as host countries introduce limits on rough exports and begin developing cutting facilities, which has happened in parts of Africa, South America, and Asia.

	The conference proceeded to an open session for invited participants to discuss topics of concern, including:

		The increasing use of color enhancement and “anti-scratch” (silicon carbide) coatings, which are virtually invisible and sometimes too thin to be detected with instruments. With advances in nanotechnology, more research is needed to develop detection strategies.

		The inconsistent use of descriptive terminology in laboratory reports, a topic carried over from the 2015 conference. The laboratories maintained that they were responding to the demands of the trade. One participant pointed out that the terms “pigeon’s blood” and “royal blue” had no meaning in Chinese culture until about ten years ago. Since then, they have become “deeply implanted,” and a seemingly irreversible demand has been created for the level of distinction that these terms confer.

		Unethical or fraudulent use of lab reports. An example cited is the treatment of a gemstone after it had received a “clean” report. Another is the manufacture of both treated and synthetic diamonds to match an existing natural diamond report. GILC participants stressed the importance of checking reports against stones through every phase of the grading process.

		The use of “undetermined” on a lab report in regard to treatment or synthetic origin. Some participants voiced concerns that such determinations are beyond the technologies of labs, or that the word “undetermined” left untreated natural diamonds vulnerable to being matched with treated or synthetic stones.

	At the conclusion of the conference, it was announced that AGTA had revised its code of ethics and principles of fair business practice. ICA is proposing to adopt AGTA’s code of ethics, due diligence protocol, and source disclosure language as a basis for its own code. @chapter:2


Publication Year: 2017 Title: Chalcedony Beads Coated With Titanium Nitride Abstract: Figure 1. The beads in this necklace, ranging in diameter from 12.0 to 12.5 mm, have a submetallic luster and a gray tinge with goldish reflection. Small vugs lined with sparkling crystals are clearly visible in most of the beads. Photos by Raffaella Navone.

Recently, RAG Gemological Laboratory in Turin received a necklace of unusual metallic appearance (figure 1). The beads showed irregular surfaces that were actually small geodes with shiny and well-shaped crystals. The cavities in the beads (figure 2) were reminiscent of the small quartz-lined holes that are often formed in agates and chalcedony. The necklace consisted of 29 beads ranging from 12.0 to 12.5 mm in diameter, with a total weight of 84 g.

Figure 2. SEM imaging shows the small, well-shaped quartz crystals within the
cavities. The crystal in the lower middle clearly displays the classic “flute”
termination typical of quartz. Image by Emanuele Costa; field of view 1 mm.
Some loose opaque beads provided by the necklace’s owner allowed us to measure the material’s density. The value of 2.60 g/cm3 was in agreement with chalcedony. Refractive index was not measurable on the beads due to their rough surface. No fluorescence reaction was observed under long- or short-wave UV. A sawed bead revealed that the inner part consisted of light gray chalcedony without zonation (figure 3). Observation of the area near the drill holes showed discoloration and the true color of the underlying material. The coating on these grayish gold chalcedony beads in this necklace had an unusual composition. The unusual color and reflectivity of the external surface, clearly not inherent to chalcedony, warranted investigation.

Figure 3. This sawed cross-section clearly demonstrates the homogeneity and light gray color of the chalcedony that constitutes most of the bead. Photo by Emanuele Costa.
The chemical composition of the bead was confirmed by energy-dispersive spectroscopy (EDS) using a Cambridge Stereoscan 360 scanning electron microscope equipped with an Oxford Inca Energy 200 EDS and a Pentafet detector for the determination of elements from boron to uranium. The results showed homogeneous composition on the sample surface, with titanium, oxygen, and silicon as major elements. No known compound of Ti and Si could explain the nature of the bead’s surface or the goldish gray metallic tinge.

Low-acceleration voltage conditions in EDS analysis (4kV) allowed us to enhance the X-ray emission yield of lighter elements and reduce the penetration depth of the electron beam at around 100 nm into the bead’s surface. The EDS spectra at low acceleration voltage showed the presence of nitrogen and titanium, suggesting a coating of titanium nitride (TiN) on the beads. At low potential the electron beam could pass through the thin layer of TiN, so the oxygen and silicon peaks from the underlying silica were still visible in the spectra. We calculated the thickness of the coating by acquiring several EDS spectra at different acceleration voltages (from 4 to 10 kV). The presence of the silicon peak even at 4 kV suggests that the electron beam could penetrate the layer and generate the signal through the TiN coat. The Casino software package evaluated the corresponding excitation depth of the electron beam using a Monte Carlo simulation. The calculated maximum thickness in our samples was less than 200 nm.

TiN is a very difficult material to analyze due to the presence of nitrogen, which is not always revealed with standard gemological techniques. To confirm the presence of a TiN film coating, we performed micro-Raman investigations. Spectra were obtained using a micro/macro Horiba LabRAM HR 800 (UV-Vis-IR) equipped with an Olympus microscope. The backscattered Raman signal was collected with a 50× objective and the 632.8 nm line of a He-Ne laser. The spectra were collected with multiple and repeated acquisitions to improve the signal-to-noise ratio, but even with these precautions the quality of the spectra is very poor due to the low intensity of Raman response from TiN. The Raman spectrum was recorded from 100 to 1200 cm–1. Spectral manipulation such as baseline adjustment, smoothing, and normalization were performed using LabSpec 5 software. Band component analysis using the Fityk software package enabled the type of fitting function to be selected and specific parameters to be fixed or varied accordingly.

The Raman spectrum of a deposited TiN film is shown in figure 4. The Raman spectrum of the TiN layer can be fitted with Gaussian-Lorentzian peaks at 260, 330, 418, and 584 cm–1. The spectrum is the same as those of TiN films reported, also with very poor quality, in the literature (Y.H. Cheng et al., “Substrate bias dependence of Raman spectra for TiN films deposited by filtered cathodic vacuum arc,” Journal of Applied Physics, Vol. 92, 2002, pp. 1845–1849). Slight variations in peak position, shape, and relative intensity can be influenced by thickness (C.C. Chen et al., “Raman spectra of titanium nitride thin films,” Chinese Journal of Physics, Vol. 32, No. 2, 1994, pp. 205–210), treatment time, and deposition temperature of TiN films (R.R.M. de Sousa et al., “Cathodic cage plasma deposition of TiN and TiO2 thin films on silicon substrates,” Journal of Vacuum Science & Technology A, Vacuum, Surfaces and Films, Vol. 33, No. 4, p. 041502), as well as substrate bias.

Figure 4. Raman spectrum of the TiN film in the 100–800 cm–1 region. The Raman
bands are related to transverse acoustic (at 260 cm–1), longitudinal acoustic
(330 cm–1), second-order acoustic (418 cm–1), and transverse optical (584 cm–1)
modes of TiN, respectively (Cheng et al., 2002). The poor quality of the spectrum,
despite a long collection time and enhanced sensitivity, is due to the faint response
of the TiN to Raman investigation (as well as to the extreme thinness of the coating);
it is comparable to the reported spectra available in the literature.
The TiN films also contained a small quantity of crystalline phase of TiO2 (i.e., brookite) that was identified in the bead coating using Raman spectroscopy. There was a close match between the collected spectrum and that of brookite available in the RRUFF database (R050363). The association of TiN and TiO2 films is well known and widely studied (de Sousa et al., 2015).

TiN deposition is widely used for the coating of small mechanical parts or tools, giving them a higher resistance to corrosion and scratching. Therefore, TiN films are essential for applications such as wear-resistant coatings, diffusion barriers, and optical coatings. The coating typically produces a golden hue, but other colors are also possible. Even though TiN films are common in industrial applications, this may be the first time such a coating has been reported in gemology. @chapter:2


Publication Year: 2015 Title: A Remarkably Large Amblygonite-Montebrasite Carving Abstract: Figure 1. This 1,871 g amblygonite-montebrasite carving (18.50 × 15.10 × 7.30 cm) is unusual for its size and transparency. Photo by Gagan Choudhary.

Recently the Gem Testing Laboratory in Jaipur had an opportunity to examine an unusually large yellow, semitransparent to translucent carving (figure 1). This 1,871 g (9,355 ct) piece measuring approximately 18.50 × 15.10 × 7.30 cm was fashioned after Lord Mahavira, one of the ancient Indian sages who established the tenets of Jain Dharma. Initial observations suggested beryl due to the color, medium heft, and cloudy liquid inclusions visible to the unaided eye. Gemological testing ruled out that possibility, however. Spot RI was approximately 1.61, with a small but distinct birefringence blink, while hydrostatic specific gravity measured 3.00. The carving was inert to UV radiation.

Examination with a hand loupe revealed reflective liquid films (figure 2, left), fingerprints composed of phase droplets, elongated phase/short tubes oriented in one direction, aligned in planes intersecting at approximately 65/115° angles (figure 2, center). Also present were parallel reflective films that appeared to be incipient cleavage (figure 2, right). The overall inclusion pattern was typical of gems found in pegmatitic bodies such as beryl, tourmaline, and topaz.

Figure 2. Examination of the carving with a hand loupe revealed reflective liquid films (left), elongated phase/short tubes oriented in one direction and aligned in planes intersecting each other at approximately 65/115° (center), and parallel reflective films that appeared to be incipient cleavage (right). Photos by Gagan Choudhary; image width 25 mm.
The carving was identified as amblygonite-montebrasite by Raman spectroscopy in the 200–2000 cm–1 region, which revealed distinct peaks at ~297, 425, 481, 600, 643, 797, 1011, 1058, 1107, and 1186 cm–1 (figure 3). Amblygonite and montebrasite are both lithium phosphates with a common chemical formula of (Li, Na)AlPO4(F, OH), forming an isomorphous series between F-rich amblygonite and OH-rich montebrasite. The two minerals can be colorless, yellow, or green. High-quality crystals are prized by collectors but rarely seen in the gem trade (R. Webster, Gems: Their Sources, Descriptions and Identification, 5th ed., rev. by P.G. Read, Butterworth-Heinemann, Oxford, UK). The amblygonite and montebrasite end members can be differentiated on the basis of peaks at ~600 and 1060 cm–1 and a peak at ~3370 cm–1. With an increasing percentage of fluorine, the 600 cm–1 peak shifts from 599 to 604 cm–1 while the 1060 cm–1 peak shifts from 1056 to 1066 cm–1 (B. Rondeau et al, “A Raman investigation of the amblygonite-montebrasite series,” The Canadian Mineralogist, Vol. 44, No. 5, pp. 1109–1117). According to the RRUFF database, however, the peak for montebrasite is at 1047 cm–1 while amblygonite’s is at 1060 cm–1. This is possibly due to different instrument settings. Although the ~3370 cm–1 peak was not studied here, the 600 and 1058 cm–1 peaks in this carving suggested that it belongs to an intermediate state in the amblygonite-montebrasite series.

Figure 3. The carving’s Raman spectrum showed major peaks at around 297, 425, 481, 600, 643, 797, 1011, 1058, 1107, and 1186 cm–1. The peaks at approximately 600 and 1058 cm–1 suggest an intermediate member of the amblygonite-montebrasite series.
Amblygonite-montebrasite is known from many localities, especially the United States and Brazil, but the client did not know the source of the carving. A few faceted samples have been examined at this laboratory, but the carving documented here was exceptional for its large size and transparency, despite its brittleness and tendency to crack. @chapter:1


Publication Year: 2015 Title: Nonbead-Cultured Pearls from Strombus Gigas Abstract: Figure 1. These two nonbead-cultured pearls (1.40 and 2.22 ct) from a parcel of eight specimens produced by Strombus gigas show a light pink and yellowish orange color with a discreet flame pattern. Photo by Olivier Segura.

Among the saltwater porcelaneous (non-nacreous) pearls, those of Strombus gigas gastropods are probably the best known among jewelers and collectors because of their vivid to pastel colors ranging from pink to white to brownish. Also known as “pink pearl,” “conch pearl,” or “Queen conch pearl,” this material was used extensively in Art Deco jewelry, and many designers are now incorporating them into modern pieces. Various articles and books have described the extraordinary beauty, use and related traditions, and early attempts at cultivation of pink pearls (see E. Fritsch and E. Misiorowski, “The history and gemology of the queen conch ‘pearls’,” Winter 1987 G&G, pp. 208–231). The typical structure responsible for the sought-after “flame pattern” was detailed extensively a decade ago (S. Kamat et al., “Structural basis for the fracture toughness of the shell of the conch Strombus gigas,” Nature, Vol. 405, No. 6790, 2000, pp. 1036–1040; H. Hänni, “Explaining the flame structure of non-nacreous pearls,” The Australian Gemmologist, Vol. 24, No. 4, 2010, pp. 85–88). Found in the Caribbean region, where Strombus gigas live and are fished for meat, the pearls had no documented cultured counterpart until the work of Hector Acosta-Salmon and Megan Davis at Florida Atlantic University in 2009.

The Laboratoire Français de Gemmologie (LFG) recently had the opportunity to analyze a parcel of eight samples, presented as cultured conch pearls, from a new farm based in Honduras (figure 1). The colors ranged from white and pinkish white to yellowish orange. The shapes varied from oval to baroque, and weights ranged from 0.21 ct (2.7–3.4 × 4.1 mm) to 3.13 ct (6.5–7.6 × 9.3 mm). Their luster was porcelaneous, and the surface was very smooth and homogenous with no defects. Almost all the samples possessed a typical but subtle flame pattern (figure 2).

Figure 2. These six nonbead-cultured pearls from Strombus gigas range from 0.21 to
3.13 ct. Inset: Detail of a 0.47 ct pearl, showing a typical thin flame pattern. Photo by
Olivier Segura.
Initial examination revealed no indication of the culturing process, but X-radiography analysis left no doubt about the material’s origin. The samples’ inner structures revealed a darker central zone, suggesting a less dense material, typical of the graft remainder of the nonbead culture process (figure 3, left). This kind of pattern is not found in the natural conch pearls we have examined in the laboratory (figure 3, right).

Figure 3. Left: An X-ray of the pearl seen in the figure 9 inset. It shows clear evidence of a nonbead culturing process. Right: An X-ray of a natural conch pearl. Images by Olivier Segura.
According to the farm owners, queen conch pearl culture is undergoing intensive development, and the quality—size, flame pattern, and color—improves with each harvest. While current laboratory techniques are adequate to unambiguously identify nonbead cultured pearls from Strombus gigas, the LFG has established a close working relationship with the pearl farm, paying close attention to possible developments in their distinctive inner structures. @chapter:14


Publication Year: 2013 Title: New Find: Blue “Cloud Agates” from Weierbach near Idar-Oberstein, Rhineland-Palatinate Abstract: The agate deposits that formed the basis of the lapidary and cutting industry at Idar-Oberstein until the 19th century are mostly depleted. What reaches the market today is the result of rockhound activities. This article reports on a remarkable find from 2012 along a road construction site at Weierbach, near Idar-Oberstein. Found in a small outcrop of volcanic rocks, the nodules showed diameters of 2–12 cm (0.8–4.8 in.). While agates from Idar-Oberstein generally have a fine banding and pastel tones, most of these agates were not banded but showed cloud-like structures and striking sky blue and red colors. The article contains numerous images of the splendid agates and the deposit.

Abstracted by Rolf Tatje @chapter:0


Publication Year: 2016 Title: Iridescent Inclusions in Scapolite Abstract: Figure 1. Orange platelet inclusions give this 2.21 ct scapolite an orange color and aventurescence similar to that of Oregon sunstone. Photo by Jonathan Muyal.

	A 2.21 ct phenomenal scapolite (figure 1), reportedly from Tanzania, was recently examined by this author. Of particular interest was its striking resemblance to Oregon labradorite feldspar, which displays aventurescence and is known in the trade as sunstone. Raman microspectrometry confirmed the stone’s identity as scapolite. Vibrant thin-film iridescence created by brownish orange exsolution platelets (figure 2) was revealed by microscopic examination; these platelets are responsible for the stone’s orange bodycolor. The exsolution platelets are presumed to be hematite based on their color, morphology, and high levels of iron detected by energy-dispersive X-ray fluorescence (EDXRF), although it was not possible to confirm this identity through Raman analysis. This scapolite’s aventurescence and pleasing orange bodycolor make it an interesting collector’s gemstone.

Figure 2. Under magnification with oblique illumination, the platelet inclusions reveal vivid multicolor iridescence. Photomicrograph by Jonathan Muyal; field of view 1.42 mm. @chapter:13


Publication Year: 2023 Title: Rare Faceted Thomsonite Abstract: Figure 1. A rare 1.04 ct semitransparent thomsonite measuring 7.53 × 6.15 × 4.67 mm. The inset shows the typical appearance of thomsonite. Photos by Adriana Robinson and Scott Lewis (inset).

Figure 2. A fibrous snowflake-like inclusion found within the semitransparent thomsonite. Photomicrograph by Michaela Damba; field of view 3.57 mm.
The Carlsbad laboratory recently examined a colorless semitransparent 1.04 ct oval modified brilliant (figure 1). Standard gemological testing gave a specific gravity (SG) of 2.47 and a refractive index of 1.520–1.538. These properties suggested the stone was a rare faceted thomsonite, which was confirmed by Raman spectroscopy. There are two types of thomsonite: the more common thomsonite-Ca with the chemical formula NaCa2Al5Si5O20 • 6(H2O) and the less common thomsonite-Sr with the chemical formula of Sr1.4Ca0.6NaAl5Si5O20 • 7.1(H2O). X-ray fluorescence was not run on this stone to determine which, for fear of damaging the potentially fragile stone. The SG reading was slightly higher than the expected value of 2.35 (+0.05/–0.10). Multiple surface scratches and abrasions indicated a relatively soft material, consistent with thomsonite’s hardness of 5.0–5.5 on the Mohs scale. This specimen featured a radiating fibrous inclusion resembling a snowflake (figure 2). Although the identity of the inclusion could not be confirmed with Raman spectroscopy, it was likely a member of the zeolite group.
Thomsonite is a rare member of the zeolite group named for Scottish chemist and mineralogist Thomas Thomson (1773–1852). While the source of this specimen is unknown, thomsonite is typically found in Minnesota along Lake Superior. It usually occurs as semitranslucent to opaque rounded crystal aggregates (figure 1, inset) with a fibrous structure. Thomsonite has also been known to appear as part of a rock aggregate (B.M. Laurs et al., “Benitoite from the New Idria District, San Benito, County, California,” Fall 1997 G&G, figure 13) or as rare needle inclusions in Canadian sapphires (Winter 2004 Gem News International, pp. 344–345). Semitransparent and faceted thomsonite is very unusual. To the best of our knowledge, this is the first faceted thomsonite examined by GIA. @chapter:13


Publication Year: 2004 Title: Winter 2004 G&G Lab Notes Abstract: Faceted Apophyllite with “Crop Circles”
Diamond Luminescent “Hopper” Diamond
“Magnetic” Natural Pink Diamond
Diamond with Many Microscopic Carbonate Inclusions
Unusual Near-Colorless Synthetic Diamond
Orangy Brown Iolite from Madagascar
Flashing Labradorite
Natural Saltwater Mussel Pearls
Treated-Color “Golden” South Sea Cultured Pearls
Quartz in Three Colors
Erratum

To view the full section, download the PDF above. @chapter:17


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

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

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

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

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

View Gallery

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

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

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

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

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

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

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

From the Bowers Museum, “A Quest for Beauty” will travel to the Houston Museum of Natural Science in 2014 and the Art Institute of Chicago the following year. @chapter:16


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

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

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

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

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

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

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

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

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

RETAIL

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

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

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

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

	Second, the U.S. dollar has risen strongly among most major currencies, which helps keep prices stable here even if it does dampen demand in foreign markets. In China, for example, the diamonds from the August sight will cost 6% more because its currency declined by that much against the dollar in the past month. @chapter:30


Publication Year: 1982 Title: Some Observations on the Treatment of Lavender Jadeite Abstract: The separation of naturally colored lavender jadeite from color-treated material is a problem that has long plagued gemologists. One theory is that the dyeing agents being used are of an organic nature. If this is true, they should break down at elevated temperatures and lose their coloring ability. Naturally colored lavender jadeite, however, should retain its color and not bleach on heating. To investigate this theory, the author sawed 42 different specimens of lavender jadeite in half. One half of each specimen was heated while the other half was retained as a color control. Those stones that bleached on heating showed a strong orange fluorescence to long-wave ultraviolet radiation before heating and a moderate bluish-purple X-ray fluorescence both before and after heating. The control halves of those stones that retained their color when heated to as high as 1000°C fluoresced a very weak brownish red when exposed to long-wave ultraviolet radiation and a strong reddish purple to pink when exposed to X-ray radiation both before and after heating. @chapter:37


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

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


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

	DATA DEPOSITORY

Photomicrographs
FTIR and NMR Spectra
Table DD-1: FTIR Spectral Features of Amber and Copal Before and After Heat Treatment
Table DD-2: Chemical Shift (ppm) of 13C NMR Spectral Features of Amber and Copal Before and After Heat Treatment
Parameters Used for NMR Spectroscopy
	Fall, 2009 @chapter:37


Publication Year: - Title: Gems of Northern Madagascar Video with GIA Field Gemology Abstract: Madagascar is one of the great wonders of our planet. Wim Vertriest, Manager of Field Gemology at GIA, takes us on a journey back in time to understand how the island acquired its incredible gemstone diversity for which it is known today. He shares highlights from a recent field gemology expedition to two remote mines in Northern Madagascar: one a demantoid mine and the other, a sapphire mine. @chapter:37


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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Treasure Hunts for Holiday Pins

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The Richard T. Liddicoat Gemological Library in Carlsbad is home to thousands of books, journals, videos and images on gems and jewelry. GIA librarians often use those resources to create displays on a specific theme to encourage students, staff and visitors to learn more about a topic. @chapter:21


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

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

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

Mastoloni showed us two graduated Japanese akoya necklaces that appear to date from the 1970s or ’80s. The pearls measure 7.5 × 10.5 mm and are perfectly matched, with no imperfections and a nacre coating that is just not seen anymore; he has three other strands that are slightly smaller. These sizes are “almost unheard of” in akoyas and make for an unusual addition to a collection. He also showed his “cloud” necklace (figure 1, right), one of his most popular, created from Chinese tissue-nucleated pearls. Chinese pearls are sold by weight, and the cultivators are using larger nuclei to create larger pearls. Since pearls are no longer grown in the sizes used in this necklace, this material is unlikely to be found on the market despite its popularity. @chapter:21


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

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

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

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


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

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

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

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

The growth tubes in this sample were an unusual feature, last seen in a selection of HPHT-grown synthetics several years ago at GIA’s West Coast laboratory. They appear similar to synthetic moissanite growth tubes, though there are a few key differences. Whereas the growth tubes occur in only one direction in synthetic moissanite, they could be seen growing in different directions in this synthetic diamond. The tubes in synthetic moissanite also tend to be very straight, while the ones in this sample curved and changed direction. Although this stone bore some superficial resemblance to moissanite, its gemological properties were quite different, another reminder to avoid quick sight identifications. @chapter:15


Publication Year: 2013 Title: Paramagnetic Hole Centres in Natural Zircon and Zircon Colouration Abstract: This article explores atomic defect centers (color centers) of natural zircon from three localities: North Carolina, the Massif Central in southern France, and the Ural Mountains of Russia. The origin of zircon coloration is little discussed in the spectroscopic literature. This study further explores paramagnetic properties and optical absorption, and also suggests additional constraints in the nature of some color centers occurring in natural zircon.

Electron paramagnetic resonance (EPR) and optical absorption spectroscopy are used on a heterogeneous sample group of 11 small untreated zircon crystals. The findings indicate an obvious correlation between color and certain paramagnetic defect centers in the crystal structure. But the EPR studies also show that the presence of tetragonal centers of trivalent rare-earth elements and niobium is not directly related to any specific zircon coloration.

The paper discusses the highly technical EPR spectral indications for electron and hole defect centers (e.g., angular dependencies and crystal axes, principal g-values), as well as the intricate substitutional charge patterns that reflect the isomorphism of zircon.

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

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

Abstracted by Edward R. Blomgren @chapter:9


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

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

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

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

Cleaning
It’s safe to clean turquoise jewelry with warm, soapy water, but it should never be cleaned with steam or ultrasonic cleaners. Some turquoise is treated to improve its surface appearance. Heat or solvents can damage the treated surfaces. @chapter:2


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

To view the full section, download the PDF above. @chapter:32