# Publication Year: 2019
# Title: Separation of Kornerupine and Prismatine
# Abstract: Figure 1. The two stones on the far left, corresponding to the blue analytical points in figure 2, were classified as kornerupine. The center 20 stones, corresponding to the yellow analytical points in figure 2, were classified as prismatine. For the eight stones on the right, corresponding to the red analytical points, the species could not be determined. The species classifications of all the stones were based on chemistry acquired by LA-ICP-MS. The largest stone is the 11.9 ct brown oval at the top of the center group. The smallest is the light blue cushion stone at the bottom of the center group, weighing 0.93 ct. Photo by Diego Sanchez.

Kornerupine and prismatine form a solid solution series with a general chemical formula of X(□,Mg,Fe)M(Al,Mg,Fe)9T(Si,Al,B)5(O,OH,F)22 (X: cubic site; M: octahedral sites; T: tetrahedral sites). Chemically, they differ mainly in magnesium, iron, aluminum, and fluorine content, with boron content that ranges from 0 to 1 apfu (atoms per formula unit) in one of the tetrahedral sites. When the boron apfu is less than 0.5, the mineral is classified as kornerupine; above 0.5, it is classified as prismatine (E.S. Grew et al., “Prismatine: revalidation for boron-rich compositions in the kornerupine group,” Mineralogical Magazine, Vol. 60, No. 400, 1996, pp. 483–491).
GIA laboratories have recently implemented a method using laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) to quantify boron concentration in kornerupine and prismatine in order to distinguish the two. The 30 stones shown in figure 1—all thought to be kornerupine—were borrowed from the GIA Museum and tested using a Thermo Fisher iCAP Qc ICP-MS, coupled with an Elemental Scientific Lasers NWR213 laser ablation system. GSD-1G and GSE-1G (U.S. Geological Survey) and NIST 610 were used as external standards. 29Si was used as an internal standard. Three 55 μm circular spots were ablated on the girdle of each stone. The data reduction was a modified version of that used at GIA for tourmaline (Z. Sun et al., “A new method for determining gem tourmaline species by LA-ICP-MS,” Spring 2019 G&G, pp. 2–17). As a result, we have slightly modified the criteria for separating the two to account for analytical error. If the boron apfu is between 0 and 0.45, the stone is classified as kornerupine. Between 0.45 and 0.55 apfu, the species cannot be determined by this method. If the boron apfu is between 0.55 and 1, the stone is classified as prismatine. For three spot analyses, if one spot has a boron apfu between 0.45 and 0.55, the species is undetermined.

Figure 2. The Al-B plot shows three sections. When the B (apfu) is between 0 and 0.45, stones are classified as kornerupine (blue spots). When the B (apfu) is between 0.45 and 0.55, the species for the stones (red spots) cannot be determined. When the B (apfu) is between 0.55 and 1.00, stones (yellow spots) are classified as prismatine. For three spot analyses, if one spot has a B (apfu) between 0.45 and 0.55, the species is considered undetermined.
All analytical points were plotted in figure 2 (full chemical results are in appendix 1). There were 2 kornerupine, 20 prismatine, and 8 undetermined species, for a total of 30 tested stones. This result suggests that, contrary to popular belief, prismatine may be a far more common gem species than kornerupine, which is also supported by the analyzed boron concentration of many production stones submitted to GIA laboratories. Interestingly, for the five green stones tested here the species could not be determined, although they slightly favor prismatine chemistry (some of the red spots in figure 2). Aluminum apfu is also a good indicator for separating kornerupine from prismatine. Boron-rich prismatine has an Al apfu around 5.8 to 6.0, compared to boron-poor kornerupine with an Al apfu around 6.6 to 6.8. Extra Al in kornerupine functions as a substitute for B in one of the tetrahedral sites in the crystal lattice.
Kornerupine is an appropriate group name for kornerupine-structure minerals of an unknown boron content or for cases where the species cannot be determined. For extreme cases, such as when boron apfu is close to 0 or 1, Raman spectroscopy could be sufficient to separate kornerupine from prismatine (B. Wopenka et al., “Raman spectroscopic identification of B-free and B-rich kornerupine (prismatine),” American Mineralogist, Vol. 84, No. 4, 1999, pp. 550–554). However, the more accurate separation for the two is determined by LA-ICP-MS analysis because the species definition is based on concentration of a chemical element, boron. @chapter:7 @chapter:0 @chapter:7


# Publication Year: 2017
# Title: Book Review: Gem: The Definitive Visual Guide
# Abstract: Foreword by Aja Raden, hardcover, 440 pp., Dorling Kindersley, New York, 2016, $50.00.

	The first edition of Gem: The Definitive Visual Guide is a visual encyclopedia driven by spectacular images of world-class gems, artifacts, and jewels. Developed in association with the Smithsonian, with a foreword by jeweler and scientist Aja Raden, the book is a good resource for amateur to professional gemstone lovers.

Gem starts with an introduction to basic concepts of geology and mineralogy, the roots of modern gemology. It then moves to more specific descriptions of gemstone resources, mining, manufacturing, evaluation, and the concept of a jewel. The introduction is a quick reference for readers without a science background or familiarity with the gem and jewelry industry.

	The main body of the book is divided into “Native Elements,” “Gemstones,” “Organic Gems,” and “Rock Gems and Rocks.” These titles are commonly used in comprehensive gemology publications and textbooks, but here the items under each one do not follow the standard alphabetical mineral list. “Native Elements” covers precious metals and diamond, though diamond is typically considered a gemstone. The famous Hope diamond is also described here.

	The other three sections also introduce both gem species and special single stones. Images illustrate each gem species, rough stone, polished or faceted stone, and jewelry piece. The physical properties of each are also listed. Famous crown jewels, appealing artifacts, and jewels of significance or owned by historical figures or celebrities are detailed. From Byzantine to ancient Egyptian jewels, from the Maharaja of Patiala’s diamond and ruby necklace to the Chinese luxury birdcage of the Qing dynasty, and from King Ludwig II’s gold pocket watch to the Duchess of Windsor’s Cartier flamingo brooch, readers can not only learn the basics of gemstones but also enjoy a visual tour of jewelry history.

	The jewels and artifacts are illustrated by high-resolution images and historic paintings. Some are even accompanied by a timeline tracing their history, as with the Crown of the Andes, for example. From around 1500, when the center emerald was attained, to 2015, when the crown was sold to the Metropolitan Museum of Art in New York City, it has been gradually modified and changed owners. These stories could lead the readers to more in-depth research on certain items.

	The last hundred pages of the book are devoted to several very useful tools, including a color guide, a mineral and rock directory, a glossary, and an index. The mineral and rock directory is very handy for professionals for quick fact checking. The color guide and the index can help readers easily find related content in the book, while the glossary provides brief definitions of important concepts and terms.

Gem is a very visually appealing work and a good choice for any gemology or jewelry book collection. It would also be a meaningful gift for gem and jewelry lovers. @chapter:17 @chapter:0 @chapter:17


# Publication Year: -
# Title: Ametrine History and Lore
# Abstract: Concave facets on the pavilion contribute to the striking look of this 27.50-ct. ametrine. Creative gem cutters sometimes use concave facets to give a gem a dramatic appearance. Photo by Robert Weldon/GIA, courtesy Minerales y Metales del Oriente.

                      The world’s only commercial source of ametrine is the Anahi mine in southeastern Bolivia. Legend has it that a Spanish conquistador discovered the mine’s location in the 1600s and introduced the gem to Europeans when he presented several specimens to his queen. The mine had been given to him as a dowry when he married a native princess named Anahi. After that, the mine was lost for more than three centuries. Rediscovered in the 1960s, the mine’s ametrine began appearing on the market again during the 1970s. Today the mine, named Anahi for the legendary princess, also produces natural amethyst and citrine.

	The mine, located near the center of the photo, is barely visible through the foliage between the two mountains. Photo by Robert Weldon/GIA.
The mine area is remote. Travel to and from the mine is limited to a flight in a small airplane or by a combination of roads and boats. Some supplies and personnel travel to and from the mine by air. Supplies and mine production move by boat. It’s not hard to imagine why the mine’s location was lost for centuries.

	A clearing near the mine has space for only a small airplane. Photo by Robert Weldon/GIA.

	A miner pushes a cart full of waste material in the depths of Bolivia’s Anahi ametrine mine. Photo by Robert Weldon/GIA. @chapter:30 @chapter:0 @chapter:30


# Publication Year: 2014
# Title: More of the Interesting and Unusual – Tucson 2014
# Abstract: Figure 1. This emerald crystal, reportedly from Muzo, Colombia, is approximately 35 mm long and contains an eye-visible multi-phase inclusion. The gas bubble within the inclusion moves a few millimeters as the crystal is tilted. Photo by Duncan Pay, courtesy of William Johnson, Natural Formations.

Some of the most captivating Tucson exhibits were among the hardest to categorize, although many could be described as phenomenal. From asterism and opalescence to bold and bright patterns, Tucson attendees encountered an abundance of fascinating and unique finds this year.

	Gary SommerConsilio Designs, LLC

The array of bright colors seen in Taiwanese “seven-color jade” comes from serpentine and actinolite within the stone.
Gary Sommer of Consilio Designs, purveyor of “seven-color jade” out of Taiwan, says that each of his decorative pieces is different, and customers tend to get overwhelmed because they like every one they see. The tough and glossy pieces, from vases to tables, are splashed with bright color, a look Sommer says is caused by serpentine and actinolite in the mix. The one-of-a-kind items are manufactured in Taipei.

	Dmitriy BelakovskiyExotic Minerals of Russia

Key concepts of synthetic quartz growth include an understanding of crystallography and the use of seed crystals in an autoclave.
Trace elements like iron and cobalt, combined with high pressure and high temperature in an autoclave, produce brand-new crystals in vivid colors from Dmitriy Belakovskiy’s Exotic Minerals of Russia. The New Jersey company grows synthetic crystals from natural rough that are both beautiful and useful.

Belakovskiy is curator of the Fersman Mineralogical Museum in Moscow; Exotic Minerals of Russia, his side business, sells Russia-grown synthetic quartz, synthetic diamonds, and synthetic moissanite. His most interesting specimens show the result of synthetic quartz growth on natural quartzite: The regeneration of broken natural quartz crystals with synthetic tips produces a result that bears a strong resemblance to natural quartz.

However, Belakovskiy emphasizes that synthetic quartz can be distinguished from natural by its lack of horizontal striations perpendicular to the c-axis. These striations are always present in natural quartz.

In addition to sharing his unique creations and their genesis, Belakovskiy sheds light on the relationship of the seed plate used to initiate and control growth and the finished synthetic crystal. According to Belakovskiy, natural quartz seeds produce clear synthetic crystals with fewer defects.

	Jim BushnellPyramid Peaks Gems

A lapidary reveals how to spot star and cat’s-eye effects in rose quartz rough and orient the material to best display these phenomena.
Colorado Springs company Pyramid Peaks Gems brings asteriated rose quartz to market, which conceals its winking stars and eyes within cloudy rough. Cutting to reveal the hidden phenomenon to its best advantage takes a lot of practice, according to owner Jim Bushnell.

	Artur F. Silva Jr.AFS Gems

Through a combination of heat and irradiation, a Brazilian company is producing treated quartz with “kunzite” or “strawberry” colors that are completely stable.
Out of Minas Gerais, Brazil, come two types of treated quartz offered by Artur F. Silva Jr. of AFS Gems. A heated, irradiated quartz in a lilac hue reminiscent of kunzite holds its color well and shows either a milky quality or an opalescent effect when polished. Silva’s “strawberry” quartz of mottled pink and white is heat treated only, and at first blush looks nothing like the plain brownish-gray material it once was.

	Paul CoryITECO, Inc.

An initiative to raise market awareness of certified untreated U.S. gemstones such as turquoise from a mine near Kingman, Arizona, and benitoite from a single source in California.
Paul Cory of Iteco has the blues—from rare sky-blue turquoise specimens to all shades of blue benitoite, faceted and sparkling with dispersion. Find out how his Mountain Certified program informs consumers and learn more about a unique, rare gem whose supply is fast waning.

Benitoite is the true California gem; the mineral occurs only in the Golden State in only one mine in the world. According to Cory, benitoite’s high dispersion and refractive index make its lively blues more akin to diamond than to sapphire. Cory’s connection with benitoite began in 2001, when an associate of his asked him to find a use for the broken crystals associated with mining benitoite; over five years, Cory accumulated a considerable amount of rough benitoite suitable for cutting faceted stones, which he now offers for sale.

According to Cory, because the only commercial benitoite mine is now shuttered, except to collectors, the unique gem is becoming scarce indeed: “When it’s gone, it’s gone!” he asserts.

Cory’s enthusiasm for the blues extends to rare turquoise for collectors, in colors ranging from green to light blue to dark blue, from the Kingman mine in Arizona. The specimens, produced from botryoidal growth around a small quartz nucleus, have received no stabilization treatment.

Cory plays a central role in developing a stronger market awareness for gemstones originating in the United States, as well as for the value of untreated gemstones. To that end, he has initiated a program, “Mountain Certified,” for designating gems from the United States that are untreated and in whose mining he has been personally involved.

Figure 2. This spectacular 7,043 ct turquoise nugget was recovered from the Lavender Pit mine of Arizona in 1934. Lavender Pit was adjacent to the much larger Bisbee copper mine. Much of the turquoise from Arizona’s mines was reputedly smuggled out by copper miners, and thus referred to as “lunch bucket” turquoise. Photo by Eric Welch, courtesy of Studio GL.

Figure 3. These curious examples of “crazy quartz” are reportedly from basalt cavities in the Gobobos Mountains of Namibia. These well-formed colorless quartz crystals are capped by smaller amethyst-colored tips in a “reverse scepter” formation. The crystal cluster is approximately 6 cm wide. Photo by Eric Welch, courtesy of Stefan Reif, Reif Collection.

Figure 4. These slices of liddicoatite tourmaline display colorful growth zoning. The largest slice measures approximately 30 cm. Photo by Duncan Pay; courtesy of Frederic Gautier, Little Big Stone.
Among the other fascinating materials seen in Tucson were a Colombian emerald crystal with an eye-visible multi-phase inclusion (figure 1), a large nugget of turquoise (figure 2), some interesting quartz from Namibia (figure 3), and large colorful slices of liddicoatite tourmaline (figure 4). @chapter:30 @chapter:0 @chapter:30


# Publication Year: 2018
# Title: Gemstone Guidebook Project
# Abstract: Figure 1. A miner in northern Tanzania examines rhodolite rough from a local deposit. Photo by Robert Weldon/GIA.

Selecting Gem Rough: A Guide for Artisanal Miners was researched, photographed, written, and produced by GIA and distributed in Tanzania through a joint venture between GIA and the nongovernmental organization Pact. It is an educational tool to help artisanal and small-scale miners understand the value of rough gem material. The pilot program was launched in four villages in the Tanga/Umba area of northern Tanzania in the first half of 2017. The sites were selected by Pact staff, who also helped deliver the content and monitor the impact of the training. The region produces a variety of garnets (figure 1), sapphire, tourmaline, and zircon.

Figure 2. Gemologist Marvin Wambua (right) shows women miners how to use the white tray to sort gem rough. Photo by Robert Weldon/GIA.
The guidebooks, written in Swahili and showing different types of gem rough found in the area, were distributed to the Tanzanian miners along with small white trays. These trays are used to sort gem rough in reflected or transmitted light (figure 2), which allows stones of higher quality to be separated.
The pilot program reached approximately 200 miners. Participants were surveyed afterward on the effectiveness of the training, and many reported a better understanding of gem quality. Women miners in particular said the training gave them a greater sense of financial independence, indicating that they might be more likely to sell rough on their own rather than rely on men. Using the responses to the survey, Pact calculated that for every $1 invested in the program there was a $12 social return on investment.
In their impact report, GIA and Pact identified areas that might benefit from this resource. GIA has decided to proceed with the project, with plans to include a number of gem localities throughout Tanzania. This expansion is expected to take place in late 2018 and in 2019. @chapter:50 @chapter:3 @chapter:50


# Publication Year: 2018
# Title: Second World Emerald Symposium
# Abstract: Figure 1. GIA’s Shane McClure led the discussion panel on country of origin. Joining him, from left to right, were Kenneth Scarratt, Taijin Lu, and Claudio Milisenda. Photo by Tao Hsu.

Hosted by Fedesmeraldas (the Colombian Emerald Federation), Acodes (the Emerald Exporter Association), Aprecol (the Emerald Producers Association), Asocoemeral (the Emerald Dealers Association), and Minminas (the Ministry of Mines), the second World Emerald Symposium was held in Bogotá October 12–14, 2018.
The inaugural event in 2015 was themed “Be part of the change.” Three years later, the emphasis was on sustainability, blockchain, nanotechnology, and traceability. Does the community share the benefit from the companies? The future of the emerald industry should develop with the local communities through education, improving health care and working conditions. These questions/keywords were among the important topics expressed during this second edition of the symposium.
More than 60 Colombian and international speakers and panelists presented a wide variety of topics such as gemology, ethics, government, stakeholders, and marketing before a large audience from around the world and representing all levels in the emerald industry.
Day one began with opening talks by Colombian officials, symposium organizers, and presidents of gem and jewelry associations (ICA, CIBJO, and AGTA). This was followed by geology and mining sessions. Gaston Giuliani (IRD, CRPG, Nancy, France) again offered an exciting talk on world emerald deposits in the 21st century, assessing current knowledge, types of deposit, and exploration. Lee Groat (University of British Columbia, Vancouver) spoke on emerald occurrences in Canada’s Yukon Territory and the challenges for exploration and exploitation. Gian Carlo Parodi (National Museum of Natural History, Paris) reviewed the species and varieties of the beryl group and shared photos of various rare collector specimens such as stoppaniite and bazzite.
In the afternoon session on gemology, Gabriel Angarita (CDTEC Gemlab, Bogotá) introduced a new treatment for emeralds coming onto the market called “Naturalys.” He compared it to traditional oil treatment or resin and described its identification. Taijin Lu (NGTC, Beijing) discussed the recently formed Chinese national standard on emerald grading. Vincent Pardieu (DANAT, Bahrain) spoke on emerald from Madagascar and presented a well-made video from his most recent field expedition to Madagascar. Olivier Segura (L'École des Arts Joailliers, Paris) presented the school, which is supported by Van Cleef & Arpels, and its rich variety of classes such as jewelry history, gouache techniques, setting, gemology, and more.
Andy Lucas (Guild Gemlab, Shenzhen) talked about educating Chinese consumers on colored gemstones and China’s potential as a luxury jewelry market. He concluded by introducing the new education programs offered by the Guild Institute of Gemology. Alan Hart (Gem-A, London) reviewed the association’s heritage and long history. He also presented Gem-A resources such as its library, the Journal of Gemmology, and traditional education and alumni activities across the world.
This first day ended with two panel discussions, with Ronald Ringsrud and Shane McClure moderating the first. Laurent Cartier (SSEF, Basel), Gagan Choudhary (GTL, Jaipur), Rodrigo Giraldo (RGLAB, Bogotá), and Aurélien Delaunay (LFG, Paris) discussed laboratory reports on emerald treatments and the difficulties in determining the degree of enhancement. Is it a subjective call? Is a finding of minor, moderate, or significant enhancement sufficient, or would the addition of more degrees of enhancement on the reports be more accurate and benefit the industry? These were among the questions exchanged.
A second panel on gemology and origin (figure 1) was led by Shane McClure with panelists Kenneth Scarratt (DANAT), Taijin Lu (NGTC), and Claudio Milisenda (DSEF German Gem Lab). The group offered a frank discussion of many critical issues on country of origin determination. They also shared the difficulties gem labs encounter in building a reliable dataset to support country of origin determination. Potential solutions were also proposed.
The second day emphasized stakeholders’ social responsibility, ethics, and marketing. The day began with speakers from mining companies. Assheton Carter (The Dragonfly Initiative), Rosie Perkins (FURA Gems), German Forero (Santa Rosa), and Elena Basaglia (Gemfields) talked about their respective projects on sustainability and development of social programs to support local communities. Projects included modernizing the mines, developing schools, and implementing health care systems. Independent consultant Gerardo Vargas concluded the session by discussing the importance of appellation of origin for Colombian emeralds and how it would benefit and protect the market, increase value, develop the industry, and give recognition to Colombian emeralds.
After the lunch break, the session continued with Prida Tiasuwan (Pranda Group) who offered insight on Thailand’s gem and jewelry industry and its potential as a global gem and jewelry hub. Pointing at the duty-free, tax-free, and non-VAT trading system for gemstones, he talked about Thailand as a major center for colored stone education, cutting, manufacturing, and treatment.
Zhao Xin Hua presented information on the Gemstone Association of China and shared data and statistics on the Chinese colored gem market. Liu Yi (GAGCC) talked about the gem and jewelry investment hub opportunities with China. Next, Laurent Cartier (Gemstones and Sustainable Development Knowledge Hub) explained the organization’s work and discussed the challenges regarding artisanal mining, short-life deposits, stock management, and consideration of quality over origin.
The last session was devoted to ethics and corporate social responsibility. Cathlijne Klomp (LVMH) spoke about responsible sourcing of colored gemstones as well as the challenges and opportunities for creating sustainable value. Next, Charles Chaussepied (Responsible Jewellery Council) explained the RJC’s history, role, and mission. This last session was by a panel discussion regarding certifications with Edwin Molina (APRECOL) and Charles Burgess (Muzo MTC).
Day three was a half-day exploration of history. Independent jewelry specialist Joanna Hardy spoke on the Colombian emerald pocket watch from the Cheapside Hoard, the emerald and diamond parure of Empress Marie-Louise of France, and many other important antique emerald jewels. Ronald Ringsrud followed with more storytelling about people, miners, and emerald adventures. Ioannis Alexandris (Gemolithos) covered the magnificent Old Mine emeralds, historical jewelry featuring Colombian emeralds, and record-breaking auction sales. Gerard Martayan (Schlumberger) reviewed the rediscovery of the fascinating Chivor emerald mine.
Closing keynote addresses by Shri Pramon Agrawal (GJEPC), Carlos Amaya (governor of Boyacá), and Oscar Baquero (Fedesmeraldas) concluded the 2nd World Emerald Symposium @chapter:50 @chapter:3 @chapter:50


# Publication Year: 2019
# Title: Wild & Petsch: Sourcing Rough and Cutting in Idar-Oberstein
# Abstract: Figure 1. This cuprian tourmaline from Mozambique measures 37 × 26.5 mm and weighs 109.62 ct. Photo by Kevin Schumacher, courtesy of Wild & Petsch.

Wild & Petsch (Idar-Oberstein, Germany) was formed when two established companies, headed by brothers-in-law Alexander Wild and Thomas Petsch, joined forces. The roots of the merged company go back to 1901. Today the firm is still sourcing rough and faceting stones in their 15-cutter workshop in Idar-Oberstein. Over the last few years they have increased their quality levels, embracing the slogan “Nothing leaves our offices that is not perfect.” While most of their work involves freeform hand faceting, machine-assisted techniques are used during preforming to achieve optimal results. They supply other businesses mainly through trade shows and an international network of distributors.
According to Alexander Wild, high-quality material is not limited to facet-grade rough. Wild & Petsch produces faceted stones, cabochons, and beads, but all must be of the highest quality. To guarantee high standards of their craftsmanship, the firm has started an apprenticeship program. During this three-year period, enrollees learn high-level lapidary skills in the company’s professional workshop while attending school. After this period, they are certified as gem cutters, and after a few more years they can receive the distinction of Master Gem Cutter. The region has seen a renewed interest in lapidary work among young men and women.
All the material cut in the workshop is sourced by Wild & Petsch. They travel to the producing areas and buy as close to the mines as possible. In some cases, this means buying at the source, which requires a strong relationship with the mine owners. Wild & Petsch has such relationships with tourmaline miners in East Africa. Elsewhere, they collect stones in the local markets (e.g., Arusha, Tanzania) where material from a wide area comes together.
Wild said the rough trade has not changed much in the last few decades. As new sources are found, it remains extremely important to maintain contact with the source and the end client to strike the best deals. Flexibility is key, as they must be able to check out new finds right away. For example, the majority of beryl is sourced from Africa, but in the mid-1990s the most amazing materials came from Ukraine and other former Soviet states. Without an extensive international network that covers nontraditional mining areas, such opportunities would be missed.
The biggest change in recent years is likely the speed at which information travels. Today a single social media post about a new find can alert the whole world, but simply having that information is not sufficient. Rough buying is clearly more complex than traveling to mining areas with sufficient funds. Being able to judge parcels quickly in terms of quality and value—and having the confidence to invest in the material—requires years of experience. This is not a skill that can be learned in school. In this area, established companies like Wild & Petsch have an enormous advantage.

Figure 2. A non-cuprian green tourmaline from Mozambique, weighing 37.01 ct and measuring 22 × 17.5 mm. Photo by Kevin Schumacher, courtesy of Wild & Petsch.
For Wild & Petsch, the most exciting material in the last five years has been Mozambican cuprian tourmaline (figure 1), which satisfies a market demand created by the original Paraíba tourmalines from Brazil. Another exciting find is green non-cuprian tourmaline from Mozambique (figure 2), with its fresh, minty colors and blue-green tones. Apart from tourmaline, the company works with a wide range of colored gemstones, including different beryls, fine tanzanite, and African garnets.
Wild acknowledged that regional trends strongly impact rough buying and finished goods sales, using the interest in bicolor tourmaline from Asia about 10 years ago as an example. Many dealers had those stones in stock for decades already, with prices established. Clients paid a premium for these tourmalines, and everyone was happy to sell their old stock for an additional profit; this also raised prices at the source. This unusual market behavior did not last, and prices quickly collapsed. As a result, many people are now sitting on very expensive rough material that does not conform to current market prices. Even though those trends impact the trade on different levels, Alexander Wild stands by the motto “Good taste is international.”
Responsible practices have become increasingly important in the gem trade, and Wild & Petsch is working on its own set of standards to provide to customers. Wild said that his larger clients have already requested such information. He noted, “This is a rocky road with many challenges and obstacles. We will have to take a realistic approach and acknowledge that there will be limits to what we can do and not everything is within reach. Unfortunately, you can’t control the world.” Wild does believe that everyone in the trade should see how they can apply responsible practices in sorting, cutting, manufacturing, and exporting. @chapter:33 @chapter:2 @chapter:33


# Publication Year: 2021
# Title: Cat’s-Eye Opal
# Abstract: Figure 1. This 3.79 ct gray transparent opal shows dominant blue play-of-color with a distinct chatoyancy. Photo by Shunsuke Nagai.

Precious opal characteristically shows a spectacular play-of-color effect and may also display cat’s-eye or star phenomena produced by the internal structure (e.g., Winter 1990 Gem News, p. 304; Spring 2003 Lab Notes, pp. 43–44; Summer 2014 Lab Notes, pp. 152–153). Chatoyancy and asterism in opal are quite rare, however, because opal is a hydrated silica and has no repeating crystal lattice (J.V. Sanders, “The structure of star opals,” Acta Crystallographica, Vol. A32, 1976, pp. 334–338). The keys to creating and maximizing chatoyancy in opal is careful arrangement of the play-of-color patches, orienting the “brushstrokes” (stripe structure caused by misalignment of the tiny silica spheres producing play-of-color), and good cutting.
Recently, GIA’s Tokyo laboratory had an opportunity to examine a transparent double cabochon measuring 12.65 × 10.06 × 5.70 mm and weighing 3.79 ct. It showed blue to green play-of-color against a gray background as well as a distinct chatoyancy (figure 1). Standard gemological testing gave a specific gravity of 2.13 and a spot RI reading at 1.45, suggesting that the stone was opal. The brushstroke pattern within play-of-color patches and the strong bluish white fluorescence and phosphorescence after exposure to ultraviolet light were consistent with a natural origin. Advanced testing using Fourier-transform infrared spectroscopy (FTIR) also indicated that this was natural opal with no evidence of polymer impregnation and/or sugar treatment (G. Brown, “Treated Andamooka matrix opal,” Summer 1991 G&G, pp. 100–106). This opal had no synthetic features such as “snake skin” and “columnar structure” in any direction. There was no evidence that this stone was assembled.

Figure 2. Chatoyant effect caused by light reflecting off parallel brushstroke patterns within play-of-color patches. A: This opal contained several large play-of-color patches with parallel brushstrokes. B: A close-up of the brushstroke pattern seen in the white square in (A). Field of view 13.3 mm (A) and 5.60 mm (B). Photos by Makoto Miura.
In microscopic observation, this opal contained several large blue to green play-of-color patches with parallel brushstroke patterns. The brushstrokes in each patch were mostly perpendicular to the length of the stone and parallel to each other, and the light reflection from the pattern created a distinct chatoyant effect (figure 2). Because the opal was composed of large blue dominant play-of-color patches, the parallel brushstrokes and the high-dome cabochon shape produced a distinct chatoyancy against the gray background. This was a striking example of cat’s-eye precious opal. @chapter:48 @chapter:0 @chapter:48


# Publication Year: 2019
# Title: Inclusion-Rich Black Topaz from the Thomas Mountains, Utah
# Abstract: Figure 1. The black appearance of a topaz was due to these small dark mineral inclusions. Photomicrograph by Jonathan Muyal; field of view 1.44 mm.

Topaz is an important gemstone that occurs in various colors. The authors had the opportunity to examine some unusual black topaz crystals and crystal fragments whose appearance was the result of numerous small dark mineral inclusions (figures 1 and 2). The topaz originated from an undisclosed locality in the Thomas Mountains in Juab County, Utah. They were provided by Shaun Rasmussen and Krisann Morrill (SK Star Claims, Provo, Utah), who discovered the occurrence. Careful microscopic examination revealed the presence of several inclusion minerals (figure 3, top). Among these were thin, translucent brownish plates of annite/phlogopite mica; transparent colorless, spherical crystals of fluorite; and opaque black octahedral crystals of magnetite. These minerals, which are well-known inclusions in topaz, were confirmed by Raman microspectrometry.

Figure 2. A black topaz crystal specimen from the Thomas Mountains in Utah (24.8 × 17.92 × 12.29 mm). Photo by Kevin Schumacher.

Figure 3. Top: Inclusions seen in this photomicrograph include black magnetite, colorless fluorite, and brown annite/phlogopite. Bottom: Clusters of tabular wolframoixiolite crystals along with fluorite and mica inclusions. Photomicrographs by Jonathan Muyal; fields of view 0.288 mm (top) and 0.36 mm (bottom).
The most abundant inclusions—and apparently the principal cause of the black appearance—were numerous opaque flattened or stubby crystals of wolframoixiolite (figure 3, bottom), a rare complex oxide mineral with the ideal formula (Nb,W,Ta,Fe,Mn,Nb)2O4 (N. Ray, “Mineralogy and geochemistry of unusual localized W-Nb included black topaz from the Thomas Mountain Range, UT,” unpublished and undated manuscript, provided by SK Star Claims to the authors). Quantitative chemical analysis by LA-ICP-MS revealed a composition of 1.66 wt.% CaO, 2.28 wt.% TiO2, 5.52 wt.% MnO, 19.93 wt.% Fe2O3, 1.94 wt.% ZrO2, 24.66 wt.% Nb2O5, 1.17 wt.% MoO3, 1.17 wt.% Ta2O5, 40.15 wt.% WO3, and 1.53 wt.% other elements. This gave a calculated chemical formula of (Ca0.074, Ti0.071, Mn0.193, Fe3+0.620, Zr0.039, Nb0.461, Mo0.020, Ta0.013, W0.430, others0.026)1.948O4, which is consistent with the chemistry of this uncommon mineral.
The presence of both magnetite and wolframoixiolite inclusions in the topaz resulted in a slight magnetic behavior. The corroded and sometimes altered appearance of both dark inclusion phases suggests that they represent protogenetic inclusions that formed during an earlier stage of mineral crystallization in the growth environment and were subsequently incorporated within the topaz. In spite of their abundance, these different inclusion minerals did not create any optical phenomena.
We thank those who provided these samples, which represent the first black-appearing topaz we have examined. @chapter:5 @chapter:0 @chapter:5


# Publication Year: -
# Title: GIA Researchers Look Inside Black Diamonds
# Abstract: The contrast of black and white is a favorite in fashion, including jewelry. This ring, left, has 1.5 carats of black diamonds and 1.50 carats of colorless diamonds. The earrings have 1.69 carats of black diamonds and 1.76 carats of colorless diamonds. All three pieces are set in 18K gold. Courtesy of Nanci Knott & Co. Photo by Robert Weldon/GIA

The stark beauty of black diamonds has intrigued jewelry designers for decades, offering a striking contrast to their colorless counterparts in rings, necklaces and bracelets. Truly black diamonds, however, are not very common in nature and as a result, the majority in the market are treated to achieve a uniform black color.

An important source of black diamonds, both natural and treated, is the Marange deposit in eastern Zimbabwe. It is a relatively new and controversial diamond source yielding large quantities of diamonds with a combination of brown radiation stains and graphite inclusions that make them appear black or give them the ability to be treated to achieve that color. The source was discovered in 2001 by De Beers but not worked until 2006. A 2018 study by GIA researchers Karen V. Smit, Elina Myagkaya, Stephanie Persaud and Wuyi Wang reports in detail on the unique properties used to identify the color origin of Zimbabwe black diamonds and how to identify potential treatments.

Table-up images of the 40 natural Fancy Dark brown to Fancy black Marange diamonds from this study. The diamonds range between 0.39 and 3.11 ct, and between 4.47 and 8.75 mm in diameter (see table 1). All the diamonds have a dark appearance due to graphite needles and abundant radiation stains, except for four with dark clouds comprised of micron-sized inclusions of graphite. Photos by Jian Xin (Jae) Liao.
The GIA researchers analyzed a suite of 40 natural Fancy Dark brown to Fancy black diamonds, weighing 0.39 carats to 3.11 carats, for the study published in the Summer 2018 edition of Gems & Gemology, GIA’s quarterly professional journal.  All of the round cut diamonds were acquired from the trade polished and untreated. Photos show that the color is distributed unevenly in the majority of them, making them less suitable or unsuitable for jewelry.

The researchers subjected the diamonds to various tests, including several different spectroscopy methods to identify impurities and defects in the diamond crystal lattice. Inclusions (such as graphite) are normally distinguished from defects such as GR1, an irradiation-related defect that is also reviewed in the paper. DiamondView imaging was used to map the growth zoning.

DiamondView and visible light images of two diamonds that show radiation stains within fractures in the diamond. Non-luminescent regions in the DiamondView images are associated with extensive radiation damage along fractures in the diamonds. Photos and images by Karen Smit.
The black hue in many naturally colored diamonds is caused either by exposure to radiation or by inclusions of sulfides, graphite, magnetite, hematite or iron-bearing materials. Many treated black diamonds are so heavily irradiated that they look black, but instead are extremely dark green. The dark color in the Zimbabwe samples is caused by inclusions of graphite, methane or other dark minerals that are so prevalent within the stone that all or most of the diamond takes on that color. A number of them also contained brown colored radiation stains centered in the fractures.

The GIA researchers found that the majority of their Marange samples derived their dark colors from the abundant graphite needles and brown radiation stains in large fractures that reached the surface. The brown stains are likely the result of the diamonds residing at the Earth’s surface for at least 1 billion years and their exposure to radioactive fluids and minerals. While most diamonds exposed to radiation turn green, after heating to around 500-600°C these stains turn brown. While the fractured diamond probably would not survive the HPHT treatment process, they could withstand low pressure, high temperature treatment to turn them into gem-quality black diamonds.

The center of this ring features 1.13 carats of black diamonds and .56 carats of colorless diamonds. Courtesy of Four Seasons Jewelry Corporation. Photo by Valerie Power/GIA
Four of the samples had an unusual internal structure – they contained two different growth structures, octahedral and cuboid, which are called mixed-habit diamonds. The cuboid area of the diamonds had clusters of micron-sized graphite inclusions that appeared as a dark cloud. Another GIA study has shown that when heated above 1200°C, however, the graphite inclusions expand to 10 to 16 times their original size, that can create a uniform opaque black color. This makes Marange a potentially important source for treated fancy black diamonds.

The aim of the study was both to document the properties of black diamonds from Marange and to better understand how such unusual diamonds were formed. Because Marange produces a large amount of diamonds – several million carats yearly – these lower-quality graphite-containing diamonds represent a potentially major source for both treated and untreated black diamonds – especially because they tend to be larger than average run-of-mine diamonds, 5 to 7 carats.

Le Vian’s Sunflower Collection features black diamonds, which it calls Blackberry Diamonds®, and colorless diamonds, which it calls Vanilla Diamonds®. The ring, left, features .625 carats black diamonds and .375 carats colorless diamonds set in 14K gold. The earrings feature .25 carats black diamonds and .625 carats of colorless diamonds. Photos courtesy of Le Vian.
Lead author Karen V. Smit and a different team of researchers examined another group of mixed-habit diamonds from the same deposit to better understand diamond growth processes. The mixed-habit diamonds contained inclusions of ancient fluids of methane (carbon and four hydrogens). The study conducted by Smit, Steven B. Shirey, Richard A. Stern, Andrew Steele and Wuyi Wang appeared in the April 2016 issue of Lithos. Interestingly, these methane fluids were only located in the cuboid sectors of the diamonds, while the octahedral portions were free of them, due to the much faster growth rate of the cuboid sectors relative to the octahedral. These Marange diamonds are the first diamonds in which methane has been described, and has provided important constraints on how diamonds form in the deep Earth. @chapter:44 @chapter:1 @chapter:44


# Publication Year: -
# Title: Gemologist Aims to Pique World’s Curiosity in Giant Crystals
# Abstract: Leela Hutchison, GIA GG, was with the first group to explore giant crystal caves in Naica, Mexico in 2001. Since then, she has been passionate about sharing her experience and knowledge of gems, minerals and crystals with audiences around the world. Photo courtesy of Leela Hutchison

Gemologist and rock hound Leela Hutchison never imagined her lifelong passion for adventure and “intense” love of gems and minerals would lead to exploring the world’s largest crystals and sharing her knowledge with audiences around the world. But Hutchison’s interests collided in 2001, when she found herself carefully climbing over massive 40-foot-tall crystals in 100 percent humidity and temperatures near 128 degrees Fahrenheit in Mexico.

Hutchison – who describes herself as an “adventure seeker” – has carved out a career researching the giant crystals and speaking at conferences, lectures and renowned museums. She also has written a book about them that is in its second edition.

“My favorite part of my work is to pique people’s curiosity,” Hutchison says. “It’s rewarding to educate others about the mineralogy and geology of crystal growth, how they are formed and where they are found around the world.”

Miners who were drilling for silver in Naica, Mexico in April 2000 found a “bubble in the bedrock” nearly a 1,000 feet below ground: a cave of giant selenite crystals, a transparent colorless variety of gypsum.

Hutchison grew up hiking, climbing and exploring in the desert heat of El Paso, Texas and was also familiar with crystals from her work in hands-on healing. That experience, as well as connections she made from doing charitable work in the Chihuahua, Mexico area, made her a good candidate to join one of the first group of explorers of those crystals in January 2001.

Hutchison, pictured above in 2001, used her skills as an avid rock climber to navigate sharp crystals inside the dark caves. Photo courtesy of Leela Hutchison
The conditions in the caves were “challenging and near fatal,” Hutchison says. “It was an extreme, hostile working environment … we were going into areas never discovered before and we didn’t know how far, deep and wide they were.”

Inside the caves, Hutchison examined and helped document the huge selenite crystals that are believed to be the largest in the world – approximately 40 feet tall and weighing as much as 60 tons.

“Seeing the crystals for the first time was like entering into Superman’s fortress of solitude, [with] colossal sized crystals on an exo-planet in the solar system, where the temperatures were exceedingly hot and I felt as if I were suffocating,” Hutchison says.

She was eager to share her experience with others after her journey into the caves, so Hutchison began to present information and photos on them. After “overwhelming” interest, she began speaking to more audiences – such as the Explorers Club and gem and mineral societies – and learning more about the crystals herself.

A few years later, in another desert, Hutchison embarked on a new adventure when she decided to attend the 2004 AGTA Gem Fair in Tucson, Arizona. Her uncle, a jeweler and watchmaker, had recently passed away and Hutchison was helping her cousin assess the loose gems he had collected. As she received her badge to enter the show, Hutchison says she saw the GIA booth, struck up a conversation and enrolled in the On Campus Graduate Gemologist program “right then and there.”

“That was the turning point in my career of a long-loved passion as an explorer and researcher of the largest crystals found on planet Earth,” Hutchison says.

Hutchison, who earned her GIA GG diploma in 2005, says her fascination with the geology of the American Southwest led to a near-obsession for hiking deep into the canyons, mountain ranges and caves of the region as a rock hunter. Photo courtesy of Leela Hutchison
Hutchison’s research focuses on unexplained mysteries in the Chihuahuan desert and the caves, including understanding how the giant crystals were formed and whether there are more yet to be discovered. She believes there are more massive pockets of crystals that lay even deeper than the Naica mine.

“Many of my findings are from my own experiences in the Chihuahuan desert and from interviews (with experts), such as with Dr. Penelope Boston, director of astrobiology for NASA. She determined that microbes inside the crystals were over 60,000 years old and still alive, and did not match up in any database held by NASA,” Hutchison says.

Although the caves have re-flooded and are no longer accessible – the mining operations that removed water from the caves has ceased – Hutchison continues to investigate the crystals by examining other deposits of selenite in the area. She shares her research findings at conferences and museums, including the Los Angeles Museum of Natural History in September 2017. She’s also been interviewed on several national radio programs.

Hutchison relies on strong communication skills to engage her audience, and credits her GIA education with giving her the knowledge to speak professionally about crystals, gems and minerals.

“Clear communication has helped to generate and build interest, excitement and enthusiasm in audiences worldwide,” she says. “(Before earning my GG) I did not have the ability to be knowledgeable or professional to share with people the extraordinary science of these newly discovered crystals.”

This photo of Hutchison inside the caves, where the largest crystals are nearly 40 feet tall, was featured in Smithsonian magazine in April 2002. It is also the cover image of Hutchison’s book, a first-hand experience with images from her exploration. Photo courtesy of Leela Hutchison
The second edition of her book, “Journey Into the Giant Selenite Crystal Caves of Mexico,” was published in 2016. She also works individually with clients, acquiring gems and crystals for jewelry, their home or use in personal healing. Hutchison says her gemology education gave her credibility with clients and the knowledge to really understand what she was attempting to acquire, from “alexandrite to tanzanite.”

“Every year, when I attend the Tucson gem show and walk by the busy pavilion with new students wanting to enroll, I feel pride and gratitude in attending GIA,” she says. “My education was absolutely invaluable to my pursuit of interests, whether in gems or minerals.”

A year after her exploration of the giant crystals, a photo of Hutchison inside the caves was included in the April 2002 issue of Smithsonian magazine. It was an honor, Hutchison says, that came full circle at this year’s AGTA Gem Fair when she was asked to share her research with the Smithsonian Gem and Mineral Council.

“In the original article there was a quote by Dr. Jeffrey Post (chair of the department of mineral sciences for the Smithsonian Institution) and there he was in the audience as I presented to the Smithsonian,” Hutchison says. “It was really amazing, a top honor.”

Hutchison’s passion for the heart of her work – gems and minerals – remains strong. She recently spent time in Arkansas digging for quartz. A personal trip, she says, because “it’s fun to go into red clay and pull out beautiful crystals.”

She is equally passionate about building excitement about crystals, hoping to spark her audience’s interest – the way the crystals have captivated her for 17 years. @chapter:21 @chapter:0 @chapter:21


# Publication Year: -
# Title: Moonstone Quality Factors
# Abstract: Top-quality moonstones accent this beautiful platinum and diamond pendant. Moonstone has fascinated designers and gem connoisseurs for centuries. - Courtesy David Humphrey

                      When buyers select moonstones, they look for three key factors: bodycolor (background color) and color and orientation of the sheen.

Moonstones range in appearance from semitransparent to opaque and colorless to white, with a blue, silver, or white adularescent effect. Moonstone bodycolors vary widely. They can be green, yellow to brown, or gray to nearly black. Along with adularescence, some moonstones show chatoyancy, also called the cat’s-eye effect. A few show four-rayed stars in an effect called asterism.

Color
Throughout its long history, people have agreed on the qualities that the most highly favored moonstones should display: a colorless, semitransparent to nearly transparent appearance without visible inclusions, and a vivid blue adularescence, known in the trade as blue sheen. The finest moonstone is a gem of glassy purity with a mobile, electric blue shimmer.

	Along with multiple reflections of the trade-show booth’s display lights, these moonstone cabochons show a beautiful blue sheen. - Courtesy Temple Trading Company
Bodycolor should be nearly colorless and free of any yellowish, brownish, or unattractive green tints. Adularescence should, ideally, be blue. The sheen should be centered on the top of a cabochon, and it should be easily seen from a wide range of viewing angles. If a moonstone’s adularescence is only visible within a restricted viewing range, its value drops.

	Moonstone can be found in a variety of bodycolors.
In 1997, miners in Southern India discovered a new type of moonstone with a bright green bodycolor, described as “parrot green” by the trade. Moonstone’s signature adularescence floats in this sea of green. The gem also displays a light yellow pleochroism, a term used for a display of different colors in different crystal directions.

Today’s popular moonstone color variety includes orange to yellow colors called peach.

Clarity
A good moonstone should be almost transparent and as free of inclusions as possible. Inclusions can potentially interfere with the adularescence.

Characteristic inclusions in moonstone include tiny tension cracks called centipedes. They are called this because they resemble those long, thin creatures with many legs.

	The most-typical moonstone inclusions are stress cracks that gemologists call centipedes.
Cut
Moonstone might be shaped into beads for strands, but by far the most common cutting style is the cabochon, a form that displays its phenomenal color or colors to best advantage. Moonstone cabochons are usually oval, but cutters sometimes offer cabochons in interesting shapes, such as the tapered sugarloaf—an angular cabochon with a square base.

If a moonstone is cut as a cabochon, the dimensions should be uniform, and the profile shouldn’t be too flat. Very flat cabochons don’t display sheen well and have little value.

Faceted moonstones have become increasingly common. The cut heightens brilliance and tends to hide any inclusions that might be present.

	This unusual moonstone suite employs the rose cut, a style most often seen in antique diamond jewelry. - Courtesy Akiva Gill Co.
Moonstone is popular for carving into decorative jewelry elements, such as cameos or the popular “man-in-the-moon” face that plays on the gem’s name. The uneven surface of the carving combines with the shifting adularescent sheen to create a delightfully intricate and lively effect.

Carat Weight
Moonstone comes in a wide range of sizes and carat weights. Fine-quality material is becoming scarcer in larger sizes.

	Large fine moonstone is very rare, making it relatively valuable. @chapter:1 @chapter:0 @chapter:1


# Publication Year: 2018
# Title: Gilson Cat’s-Eye Synthetic Emerald
# Abstract: Figure 1. This 2.73 ct Gilson synthetic emerald cabochon displays a sharp “cat’s-eye” phenomenon. Photo by Kevin Schumacher.

In the early 1960s, French ceramist and engineer Pierre Gilson succeeded in growing and producing flux synthetic emerald of commercially marketable quality. By the mid-1970s, it was reported that Gilson commanded 95% of the world market in synthetic emeralds (J. Sinkankas, Emerald and Other Beryls, Chilton Book Company, Radnor, Pennsylvania, 1981, p. 308). While the Gilson factory is no longer active, the material is still occasionally encountered in the trade and in gemological laboratories. The authors recently examined one example, a 2.73 ct cabochon that was of particular interest for its chatoyancy (figure 1).
Gilson synthetics are often grown from seed plates of slices of natural beryl positioned parallel to the c-axis. Microscopic examination of the specimen revealed veils and wispy secondary flux fingerprint inclusions, as well as strain bands like graining aligned parallel to the c-axis, all common features of Gilson synthetic emerald. The numerous growth striae resulted from inner strain, caused by periodic growth interruptions or slight changes in chemical composition when the growth tank was recharged (Sinkankas, 1981; R. Diehl, “Neues zum Thema ‘Synthetischer Smaragd’: Besuch bei Pierre Gilson,” Zeitschrift der Deutschen Gemmologischen Gesellschaft, Vol. 26, No. 2, 1977, pp. 61–75).

Figure 2. The parallel arrangement of a network of primary flux inclusions is responsible for the cat’s-eye effect. Photomicrograph by Jonathan Muyal; field of view 2.77 mm.
Also parallel to the c-axis (the basal pinacoid of the original crystal), we observed a plane of tubes (figure 2) that was responsible for the chatoyant effect. This plane of numerous elongated bubbles/cavities containing the primary flux—and possibly minute phenakite crystals—was located near the base of the cabochon. This oriented plane of primary flux tubes also appears to result from the variation of conditions during growth.
The micro-world of flux-grown Gilson emerald has already been captured extensively (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Vol. 3, Opinio Publishers, Basel, Switzerland, 2008). But the interest of this specimen is its clever fashioning, with the plane of the coarse primary flux residue—which a lapidary would normally want to remove—oriented close to the base and parallel to it, turning this into a chatoyant specimen. In fact, this is the first time a Gilson flux-grown cat’s-eye emerald has been encountered by the authors. @chapter:10 @chapter:0 @chapter:10


# Publication Year: 2015
# Title: Large and Unusual Gems
# Abstract: Figure 1. Noor Gems showcased afghanite from Badakhshan Province, Afghanistan. Photo by Duncan Pay/GIA; courtesy of Noor Gems Japan Ltd.

              The inventory of Noor Gems Japan Ltd. at the GJX show was characterized by large and unusual gems, including a fine selection of rare blue and pink gemstones: afghanite, hauynite, hemimorphite, and pezzottaite. Bright blue afghanite (figure 1), which the company has been selling for three years, was available in gem quality in the 0.3–1.5 ct range, priced at approximately $500–$700 per carat. It has been especially popular with Noor’s Japanese clientele. Afghanite is a relatively soft stone for jewelry, with a hardness 5.5 to 6, best suited for pendants and earrings. While near-colorless material can be found in Italy and Germany, the recent production of blue afghanite is from Badakhshan Province, Afghanistan.

Mehraj Uddin exhibited two large topaz of exceptional pink to red color (6.38 and 12.08 ct). As with virtually all pink topaz, he acknowledged that these fine stones were heat treated. Debuting at Noor’s GJX booth was pinkish purple copper-bearing tourmaline from Mozambique (figure 2).

Figure 2. Another attraction at the Noor Gems booth was pinkish purple copper-bearing tourmaline from Mozambique, which they labeled as “Paraíba.” Photo by Duncan Pay/GIA; courtesy of Noor Gems.
For some large and exceptional gemstones, such as a 254.50 ct peridot cabochon from Pakistan, Uddin admitted they hold on to these stones for 10 or 20 years. The company is reluctant to sell them because of the difficulty in replacing such inventory. They will only sell when they feel the market is high. @chapter:30 @chapter:0 @chapter:30


# Publication Year: 2015
# Title: Serpentine Cabochon with Unusual Olive Green Color
# Abstract: Figure 1. This 4.05 ct translucent serpentine is unusual for its olive green color and lack of impurities. Photo by Yanjun Song.

Serpentine is a common ornamental stone in the jewelry trade. With colors ranging from yellowish green to deep green, it is commonly used as an imitation of jadeite or nephrite.

Recently, the Gem Testing Laboratory at the Shijiazhuang University of Economics in Hebei, China, examined an olive green cabochon (figure 1) weighing 4.05 ct and measuring approximately 12 × 8 × 6 mm, reportedly purchased from China’s Shandong province. The sample was relatively clean, with a vitreous luster and without any eye-visible inclusions. Without magnification, it resembled high-quality jadeite jade. Standard gemological testing gave a spot refractive index of 1.56 and a hydrostatic specific gravity of approximately 2.56; the sample was inert to both long-wave and short-wave UV. These properties are consistent with serpentine. Four main peaks were observed in the 1100–400 cm–1 region of the infrared reflectance spectrum (figure 2). The two peaks at about 1046 and 482 cm–1 were related to the fundamental Si-O vibrations. The remaining two peaks at 672 and 558 cm–1 are attributed to the OH– and Mg-O vibrations, respectively, confirming the sample’s identity as antigorite, a species in the serpentine family.

Figure 2. The FTIR spectrum of the 4.05 ct olive-green cabochon sample exhibits
characteristic peaks at 1046, 672 and 482 cm–1, all consistent with serpentine.
Energy-dispersive X-ray fluorescence (EDXRF) was used to differentiate the sample from the common “Xiuyu” variety of serpentine, from China’s Liaoning province. Testing revealed that both Cr and Ni were significantly higher in this material than in serpentine from Liaoning, indicating that the specimen may have formed from the serpentinization of mafic-ultramafic rocks. We suspect it may have originated in Taian City in Shandong province, which is famous for “Taishan jade,” a newfound variety of serpentine.

Although serpentine is common in the Chinese market, this was the first time our researchers have encountered a sample of such high quality. @chapter:12 @chapter:0 @chapter:12


# Publication Year: -
# Title: Colored Gem Market Update
# Abstract: Joshua SaltzmanNomad’s Lapidary Company

	Interview with Joshua Saltzman, Nomad’s Lapidary Company
Nomad’s specializes in a wide range of high-end colored stones such as spinel, tourmaline, peridot, garnet, and corundum, all untreated. Saltzman finds that trade shows are excellent places for educating consumers about the differences between treated and untreated stones. As he sees it, explaining to a potential buyer why a similar-sized stone at another booth costs half of what Nomad’s charges (treatment vs. no treatment) gives that customer more choices.  She can make her selection based on whether lower prices or a gem’s natural qualities are her priority.

The market for high-quality and larger pieces has tightened noticeably in the past couple of years due to much less mining and production and the resulting higher prices. Rubellite and bi-colored tourmalines were big sellers on the Chinese market, but less rough is now available and sales have slowed. Two years ago, there was a large supply of Afghani tourmaline in the bright blues that Nomad’s is known for, but now the supply has shifted to mint colors and the variety known as indicolite; Saltzman says they are selling well and “people love them.”

Saltzman shows stunning deep purple cuprian tourmaline from Mozambique, a big and beautiful aquamarine from Brazil, and lavender spinel from Vietnam. The latter demonstrates a color shift from lavender to pink in a fine specimen with a fiery, glittery radiance that Saltzman calls “sexy, feminine and soft; very popular.” Although Nomad’s also sells Tajik spinel in rose pink, and Tanzanian spinel in oranges and intense pinks and reds, their biggest seller is Vietnamese cobalt blue, which is now very hard to find in sizes over a carat.

Indeed, spinel appears to be increasingly appreciated as a gemstone in its own right, instead of as merely a lower-cost substitute for corundum. Vietnamese spinel in pastel colors is in demand and the prices are rising due to the fact that only small finds are being mined now. One reason for its popularity is that spinel tends not to be heated or treated the way rubies and sapphires often are, so customers can be confident that what they are buying is a truly natural gemstone. Nomad’s customer base is loyal because they know that the company’s combined choice of rough, cutting, and polishing produces a level of quality in untreated gemstones not found elsewhere. @chapter:33 @chapter:2 @chapter:33


# Publication Year: 2023
# Title: Israel saw a decline in diamond sales in April 2023.
# Abstract: In April 2566, the diamond trade in Israel showed a downward trend, reflecting the global diamond industry's ongoing decline, exacerbated by the fallout from the conflict in Ukraine. The first quarter of the year saw negative trends in Israel's diamond sector, with all four categories of rough diamonds decreasing. This was revealed in the first study for 2566 released by the Supervisor of Diamonds at the Ministry of Economy and Industry in Israel.
Overall, net imports of rough diamonds to Israel totaled $400 million, a decrease of 35% compared to the same period last year. In April 2566 alone, imports decreased by 7% compared to April 2565. Net exports of rough diamonds during the same period totaled approximately $351 million, marking a 45% decrease from the third quarter of 2565 and a 25% decrease from April 2565.
Net imports of polished diamonds in the first quarter amounted to $885 million, down 23% compared to the third quarter of 2565, with April 2566 showing a 22% decrease from April of the previous year. Meanwhile, net exports of polished diamonds, totaling approximately $976 million, decreased by 44% compared to the third quarter of 2565, and by 69% in April 2566 compared to April of the previous year.
In April 2566, net exports of rough diamonds to the United Arab Emirates amounted to around $17 million, accounting for 20% of Israel's total rough diamond exports for that month. During this period, approximately $9 million worth of rough diamonds were imported from the United Arab Emirates to Israel, constituting 8% of all rough diamonds imported to Israel in April 2566.
Mr. Ofir Gur, Head of the Diamond Department at the Ministry of Economy and Industry, stated, 'The continued downward trend in the global diamond trade can be observed from current study data. However, we expect a positive turnaround in the mid-year export figures due to improved sales in the Chinese market.'
Comments/Recommendations:
The diamond industry is a major contributor to Israel's revenue from diamond exports. The expertise in diamond cutting technology and craftsmanship in jewelry production are notable strengths. Gems and jewelry, including diamonds, are among the top five export commodities to Israel. Despite significant setbacks during Covid-19, recovery efforts are underway, yet global economic conditions remain challenging, affecting the vibrant sales of diamonds. @chapter:37 @chapter:3 @chapter:37


# Publication Year: -
# Title: Bench Tip #12: How to Make Spiral-Cut Rubber Molds
# Abstract: Spiral-cut rubber molds

Master models used in mass jewelry manufacturing range from simple one-part pieces to intricate multiple-part forms. Rubber molds made from these master models are the key to reproducing consistent replicas of the original in wax form for casting. Cutting a rubber mold is a master craft in itself.

A rubber mold is heat-formed around the metal master. When it’s cured, the mold must be cut to remove the model and ensure two critical outcomes: the successful injection of molten wax to completely fill the mold cavity and the release of the resulting wax replica without distortion or breakage.  Cutting a rubber mold for a plain half-round band is a fairly simple task, but cutting one for a ring with a gallery or basket setting poses certain challenges.

In this installment we present a mold cutting technique called a spiral cut, which is designed to facilitate the successful release of a cage-like wax model from a mold.

After making initial cuts and creating your mold locks, cut along the sprue, the sides of the model, the finger hole and the gallery wires. Finally, cut across flat and parallel to the top plane of the setting to expose the top of the gallery wires. Release the master.

Draw a spiral with a ballpoint pen on the top flat section of the rubber, inside the gallery wires.

Push a scalpel blade straight down into the rubber. Carefully guide the blade along the spiral. Do not force it. The blade should remain perpendicular to the top surface while cutting, and the spiral cut should be the same depth all around.

	Push a scalpel blade straight down into the rubber. Carefully guide the blade along the spiral. While cutting, the blade should remain perpendicular to the top surface and the spiral cut should be the same depth all around.
Next, you will cut the base of the spiral at the depth of the cut. The objective is to release the outer spiral but leave the center core attached. Use caution as you guide the blade.

	Cut the base of the spiral at the depth of the cut. The objective is to release the outer spiral, but leave the center core attached.
The spiral cut allows the mass of rubber within the gallery cage to uncoil and release from the center outward. With the simultaneous stretching and thinning of the rubber as it’s being pulled, the mold is essentially “poured” out of the cavity through the small opening. The result is a wax model with no distortion or breakage and a rubber mold that becomes a most valuable asset in the production process.

	The spiral cut allows the mass of rubber within the gallery cage to uncoil and release from the center outward. @chapter:28 @chapter:2 @chapter:28


# Publication Year: 2000
# Title: Lapis Lazuli from the Coquimbo Region, Chile
# Abstract: Lapis lazuli has been mined from the Coquimbo Region of Chile since 1905. Some of this material approaches the quality of fine lapis lazuli from Afghanistan. The Chilean material is composed of blue lazurite, together with wollastonite, calcite, haüyne, diopside, pyrite, and minor quantities of other minerals. The deposit is located in the Andes Mountains at an elevation of 3,500 m; it is hosted by a contact-metamorphosed limestone that was later metasomatized to introduce sulfur, a necessary component for the formation of lazurite. Two companies are currently mining the deposit, Las Flores de Los Andes S.A. and Compañía Minera LapisChile S.A., and today they produce about 150 tonnes of material annually. Much of the lapis lazuli is processed locally, for use in fine jewelry, ornamental objects, and building materials such as tabletops or tiles. @chapter:14 @chapter:0 @chapter:14


# Publication Year: -
# Title: De Beers Eases Prices Slightly, But Retailers Stand Firm
# Abstract: De Beers headquarters is located at 17 Charterhouse St., London. Photo by Russell Shor/GIA.

	De Beers’ June 10-14 sight totaled about $585 million – nearly the same as May – with slightly lower prices by 2-3% on some categories of rough, mainly those that would polish out in the range of a quarter carat to 10 points. A number of sightholders refused these goods last month because they are more expensive than the resulting polished stone would realize in the market. The small price decrease did not enable manufacturers to turn a profit, so several clients again refused to take these goods.

	De Beers’ clients, both manufacturers and rough dealers, bristled at the May price increase, which averaged just over 5%, because polished prices had been softening for several months, squeezing profitability. Dealers reportedly took a 3% or 4% loss on sight goods in May. They estimate this sight may break-even.

	Polished prices have remained stable under extreme pressure because retailers in the U.S. and around the world have pushed hard against any attempt to raise them.

Las Vegas: After slow business at the Hong Kong and Basel fairs, Las Vegas offered some relief to diamond dealers and jewelry manufacturers, but prices remained static. A combination of a reviving economy in the U.S., a sharp decline in the price of gold and the low inventories of many U.S. retailers contributed to a better than expected show for many exhibitors.

	Exhibitors at the high end Couture and Luxury shows reported strong business, but business was less consistently good in the main part of the show, particularly in the competitive area of the diamond pavilion and AGTA Gem Show.

	Diamond people generally reported good demand, though many deals fell apart over price. Exhibitors who raised prices before the show met with strong resistance from buyers and intense competition from those who kept prices steady. Retailers are not willing to pay higher prices, especially when many of them, especially in the U.S., fill a portion of their diamond needs from second-hand sources at much lower prices. In addition, diamond companies have to bear the cost of holding higher inventories because the banks have been aggressively cracking down on memo deals and long payment terms that, at their peak, accounted for as much as 70% of U.S. diamond wholesale business.

	The India diamond industry is dealing with profit drains because of the deterioration of the rupee exchange rate against the dollar, effectively raising rough prices (which are traded in dollars). The rupee hit a record low of 59 ($1) on June 12, a loss of about 10% in the past six weeks.

	Colored gemstone demand in Las Vegas was quite strong with many dealers showing high-end pieces they had previously reserved for Basel or Hong Kong.

	Exhibitors at the American Gem Trade Association pavilion noted that jewelry designers were looking for stones that would complement this year’s colorful fashion looks. Emeralds were particularly strong as was fancy color sapphire, untreated or only heat treated.

	On the main floor, designers were creating bolder colored looks from large pieces of malachite, lapis and other inexpensive, opaque material. Amethyst and citrine were also popular for the same reason.

	Exhibitors were also showing much more reconditioned second hand pieces, noting that they have become popular and are not items easily found on the Internet. @chapter:37 @chapter:3 @chapter:37


# Publication Year: 2023
# Title: Distinctive Feather in Diamond
# Abstract: A feather in a 0.30 ct diamond with I1 clarity resembled an alligator. Photomicrograph by Raju Jain; field of view ~3 mm.
Recently, the authors examined a 0.30 ct type Ia diamond with D color and I1 clarity. The diamond displayed a grade-setting feather resembling an alligator (see above), which was best observed through the pavilion facets. This unusual clarity characteristic is a charming find that adds distinction to this colorless diamond. @chapter:29 @chapter:1 @chapter:29


# Publication Year: -
# Title: Mandela Day Libraries Encourage a Love of Reading, Education
# Abstract: “Education is the most powerful weapon which you can use to change the world,” Nelson Mandela once said. Students at Refentse Primary School in Limpopo, South Africa recently expanded their education by participating in GIA’s Junior Gemologist program. Photo by GIA

ship•ping con•tain•er
noun \ˈSHipiNG kən-ˈtā-nər\
: a large metal, corrugated box used to transport goods by ship, airplane, train or truck

li•brary
noun \ˈlī- brer-ē\
: a place with a selection of books, magazines and other reading or resource materials available to borrow

The objects of these definitions may seem unrelated, but for several non-profit organizations in South Africa, shipping containers are a great solution to house school libraries where there were none before.

GIA recently collaborated with the Mandela Day Libraries project to sponsor two container libraries for nearly 1,100 students at the Moime and Refentse primary schools in rural Limpopo, South Africa.

The Mandela Day Libraries project is dedicated to bridging the gap in literacy and reading proficiency in schools throughout South Africa by recycling and retrofitting shipping containers with new flooring, insulation, electricity and bookshelves to create libraries. Breadline Africa, a nongovernmental organization and internationally registered South African-based charity, is the main partner of the program.

The new libraries are funded by the GIA endowment, which supports education and scholarship programs, and hold nearly 2,500 educational books, many of which were donated by GIA staff.

“We’re thrilled to bring these libraries to the students of the Moime and Refentse primary schools and hope they further ignite their interest in education,” said Bev Hori, GIA’s chief learning officer and vice president of education.

	Bev Hori (left), GIA's chief learning officer and vice president of education, and Alta Brown Steenkamp, Vodacom Change the World Volunteer at The Nelson Mandela Foundation, work to promote literacy through the Mandela Day Libraries project. Photo by GIA
The two GIA-sponsored libraries were unveiled Feb. 19 and 20 with opening ceremonies that included local government representatives, teachers and tribal authorities. GIA also hosted 20 pupils in its Junior Gemologist program during the events. The program offers students the opportunity to discover the world of gemology through hands-on, practical training.

Moime and Refentse primary schools mark the installment of the 36th and 37th Mandela Day library since the program’s inception in 2011. The project also trains librarians to manage the facilities and inspire a love of reading among the students.

“The students have the motivation and potential to improve the state of the world they experience,” Hori said. “Education is the key to helping them realize their visions of a better life for themselves and their communities.”

View Gallery @chapter:47 @chapter:2 @chapter:47


# Publication Year: 2022
# Title: Three-Rayed Asterism in Quartz
# Abstract: Figure 1. Asterism with a three-rayed star seen on a quartz cabochon (sample B) in reflected light with fiber-optic illumination. Photo by Martin P. Steinbach.
Asterism is a well-known (if not the most familiar) optical phenomenon observed in numerous gem species. In transparent or translucent gemstones, a series of parallel inclusions consisting of tiny needles or channels produces a distinct light band by a complex process of scattering and reflection of light. If the gemstone is cut as a cabochon, the light band, which is oriented perpendicular to the needle or channel axis, generally produces a sharp light line on the surface of the gemstone, an effect known as chatoyancy. If several series of parallel inclusions are present, we observe several intersecting light bands producing asterism. The number of rays in a star depends on the number of intersecting light bands. For example, two intersecting light bands produce four-rayed stars, three intersecting light bands produce six-rayed stars, and so on.
A single star is observed if all needles or channels are oriented parallel to a single plane. If the inclusions are found in different planes, we might observe several stars on the surface of a cabochon or sphere (K. Schmetzer et al., “Dual-color double stars in ruby, sapphire, and quartz: Cause and historical account,” Summer 2015 G&G, pp. 112–143). This effect can be due to the symmetry of the host, which causes several series of non-planar needles (e.g., in cubic spinel or garnet). Multi-asterism is also produced by several series of needles that are independent of each other, as in quartz or beryl (K. Schmetzer and M. Glas, “Multi-star quartzes from Sri Lanka,” Journal of Gemmology, Vol. 28, No. 6, 2003, pp. 321–332). A combination of these two variants is observed in garnet. All different variants may be designated as a “network of stars.”
The present contribution describes three-rayed asterism, a phenomenon that does not really fit into the generally accepted knowledge about the formation of asterism and multi-asterism. This variant of asterism in quartz is a rare optical phenomenon mentioned briefly by Gübelin and Koivula (Photoatlas of Inclusions in Gemstones, Volume 2, 2005, Opinio-Verlag, Basel, Switzerland, p. 548) and by Steinbach (Asterism: Gems with a Star, 2016, MPS Publishing and Media, Idar-Oberstein, Germany, pp. 649–651). Hainschwang (Fall 2007 GNI, pp. 261–262) observed two three-rayed stars on quartz cabochons with chlorite inclusions. The two stars had one ray in common and were observed upon rotation of the cabochon, with one of the three-rayed stars observed at another end of the ray that is shared by both stars. Hainschwang assumed that the optical phenomenon was caused by the chlorite inclusions, but the formation mechanism is not completely understood.

Our observation is based on the examination of four star quartz samples, which came from the private collection of one of the authors (MPS). The quartz cabochons were purchased at various gem and mineral fairs and were said by the vendors to originate from Brazil; further details on locality are unknown. The properties of the cabochons are summarized in table 1.
Upon first view, the samples showed broad light bands forming a three-rayed star, with all branches of the star originating from a center (figure 1). The single branches of the three-rayed stars move along the surface of the cabochons after rotation of the stone or a change of the position of the light source or the observer. So far, this observation is consistent with the features of light bands generally observed in asteriated gemstones. But in “normal” gemstones (e.g., star rubies or star sapphires), we see three intersecting light bands forming a six-rayed star.

Figure 2. Upon rotation of sample A, the center of a three-rayed star moves to the girdle and another center of a three-rayed star comes into sight (D); upon further rotation, this star is also moved. The sequence A to F shows the optical phenomenon described. Photos by Karl Schmetzer; reflected light, fiber-optic illumination.
Surprisingly, upon rotation of the cabochons it was detected that the samples did not show a single three-rayed star but a multi-star network. Rotating each quartz cabochon in a direction in which it was possible to follow one of the light bands on the cabochon’s surface, at some point this branch of the star ended in another center of a three-rayed star. Repeating this procedure, another center of a three-rayed star was occasionally detected, unless the branches of the three-rayed star ended at the girdle (figure 2).

Figure 3. Schematic representation of the multi-star network observed on the four quartz cabochons (samples A–D in table 1). The red lines represent the light bands observed on the surface upon various rotations. The patterns in A and B were observed on the round cabochons; sample C was an oval cabochon, while sample D was an irregularly shaped cabochon. The direction of the c-axis for the three transparent samples is also indicated.
Figure 3 shows a schematic representation of the multi-star networks observed in the four samples. It must be underscored that the different patterns drawn represent lines on curved domes of the different cabochons. If the branches of the stars are in a position close to the girdle, some lines that appear almost straight in the middle of the cabochon will appear more or less curved. So far, due to the different orientations of the cabochons and the different shapes, each sample represents only part of a full star network that would be seen on the surface of a complete sphere.

Figure 4. Fibrous inclusions in a quartz cabochon from Brazil showing three-rayed asterism. Photomicrograph by Karl Schmetzer; immersion, field of view 7.6 mm.
All the samples revealed a dense pattern of needle-like to fibrous inclusions (figure 4) typically described as rutile (J. Hyršl and G. Niedermayr, Magic World: Inclusions in Quartz, 2003, Bode Verlag, Haltern, Germany, pp. 82–139). However, these inclusions are mostly bent or curved, and no series of parallel needles or channels were seen under the magnification of a gemological microscope (up to 100×). It is uncertain how these curved rutile inclusions, sometimes described as “fibers” or “hairs,” contribute to the phenomenal pattern observed.
The mechanism responsible for the observed multi-star network is unknown; it could be caused by structural features or inclusions. However, quartzes with similar rutile inclusion patterns from Brazil (as shown in figure 4) and elsewhere generally do not show three-rayed asterism or the type of three-rayed asterism network described here. It is possible to create a single three-dimensional network by a combination of the variants seen in figure 3, A–D. But this would be highly speculative, since we cannot (based on the samples available) prove that all variants seen so far contribute to one single pattern. @chapter:19 @chapter:0 @chapter:19


# Publication Year: 2024
# Title: Exceptionally Rare Titanoholtite
# Abstract: Figure 1. A 0.85 ct oval modified brilliant titanoholtite. Although its bodycolor was dark orangy brown, a bluish haze was visible from certain angles due to light scattering off polish lines as well as internal colorless graining. Photo by Adriana Robinson.
A first-time submission of a rare dumortierite supergroup member was recently examined at the Carlsbad laboratory. A 0.85 ct titanoholtite (figure 1) was identified after extensive testing. The stone was submitted as dumortierite, but its physical properties and chemistry did not support this. The dark orangy brown stone had a hydrostatic specific gravity of 3.65 and a refractive index of 1.720–1.740 (birefringence of 0.020). These properties stand in contrast to dumortierite, which usually forms as an inclusion rather than a single crystal and typically has a blue to violet color, a specific gravity of 3.21 to 3.41, and a refractive index of 1.659 to 1.692 with a birefringence of 0.027.

Figure 2. Left: A clean and reflective surface-reaching fracture was seen under the table; field of view 3.57 mm. Right: Abundant transparent graining, scattered particles, and thin films were seen throughout the stone; field of view 2.34 mm. Photomicrographs by Britni LeCroy.
A look into the stone offered a vibrant scene composed of a reflective surface-reaching fracture breaking the crown (figure 2, left) and an abundance of transparent graining throughout with small flecks of reflective thin films and unidentified particles (figure 2, right). Microscopic observation revealed a strong resemblance to garnet, but the material’s doubly refractive nature was inconsistent with garnet. Raman spectroscopy results did not match any existing minerals within GIA’s reference databases, but they did show some general similarities with dumortierite. Finally, laser ablation–inductively coupled plasma–mass spectrometry was performed on the stone for a full quantitative chemical analysis. Given the general similarities with dumortierite, the chemical data was fit to a dumortierite supergroup formula of (Al0.35Ti0.41□0.24Fe0.02)Al6B(Si2.60Sb0.32)O17.67. The dominant component in this formula is titanoholtite, (Ti0.75□0.25)Al6BSi3O18, with minor dumortierite, Al7BSi3O18, and incorporation of significant antimony.
Titanoholtite is a recently discovered mineral within the holtite group and a member of the dumortierite supergroup. It was first published in 2013, when microscopic crystals were found in a Polish pegmatite (A. Pieczka et al., “The dumortierite supergroup. II. Three new minerals from the Szklary pegmatite, SW Poland: Nioboholtite, (Nb0.6□0.4)Al6BSi3O18, titanoholtite, (Ti0.75□0.25)Al6BSi3O18, and szklaryite, □Al6BAs3+3O15,” Mineralogical Magazine, Vol. 77, No. 6, 2013, pp. 2841–2856). This stone submitted to GIA appears to be the first macroscopic titanoholtite specimen ever reported in the literature. @chapter:15 @chapter:0 @chapter:15


# Publication Year: -
# Title: Bench Tip: Avoid Stone Loss With Quality Assurance Benchmarks
# Abstract: Bench Tip: Avoid Stone Loss With Quality Assurance Benchmarks

Fine jewelry represents much more than its trade value in diamonds, gemstones and precious metals. It is a personal representation of the owner’s lifestyle, status, emotion, recognition, commitment and more.

That significance only amplifies how devastating the loss of a gemstone is for the owner. Even one missing accent stone renders the jewelry unwearable. Loss of a significant gemstone will also impact the retailer who sold the piece and the manufacturer who engineered and produced it.

The loosening, damage or loss of gemstones in jewelry can be attributed to two factors: poor workmanship or the absence of benchmarking standards for setting. Benchmarks are specific parameters used to compare and evaluate the acceptability of a finished product for market.

Stone loss can be avoided. Inspecting each piece and comparing it against established benchmarks for signs of vulnerability in normal wear gives the jeweler/manufacturer an opportunity to address potential problems before jewelry is offered for sale. Adopting consistent task-specific benchmarks encourages sound design and good workmanship, assuring the quality of jewelry for the consumer.

Examples of the quality assurance benchmarks presented here are for setting round brilliant gemstones in traditional angled prongs.

	This drawing shows benchmarking criteria for angled prongs on a center stone.

Prong Setting Benchmarks – Traditional Angled Prongs

A: Prong angle is 70-80 degrees.

B: Sufficient prong thickness is needed to secure the stone in place, so 40-50% of the metal is removed from the prong thickness at the bearing.

C: Diamond is seated level in the bearing just above the gallery wire. There are no gaps in any bearing – the bearing is the cut made in a prong and must precisely fit the stone contour when properly set. Any gaps will allow the stone to move or loosen.

D: Finished prong height is 75-85% of table height. Ample prong height allows the prong to hold up through normal wear.

E: Prong contact is 33-50% of total crown distance. Adequate prong contact over the crown is critical to a stable setting.

F: Prongs are rounded, polished and consistent in size and shape.

Potential Errors in Workmanship for Traditional Angled Prongs

Example 1: Using benchmarking quality assurance benchmarks, you will note a bearing was not cut (lower blue arrow) and the diamond is not seated. Prong contact is insufficient (upper blue arrow) and barely secures the diamond.

	This center stone has no bearing.

Example 2: The bearing does not conform to the crown and pavilion angles of the diamond, so there are large gaps. Too much metal was removed from the prong thickness.

	This prong is overcut and there is visible open space at the bearing.

Understanding what to look for and following consistent quality assurance practices will enable our industry to ensure that our global consumers have the best possible jewelry experiences. @chapter:50 @chapter:3 @chapter:50


# Publication Year: 2020
# Title: Diamond with Cavities Showing Radiation Evidence
# Abstract: Figure 1. This 0.70 ct natural diamond contained an inclusion of wollastonite and CaSiO3-breyite with a large disk-like graphitic fracture due to exhumation from the mantle. Photomicrograph by Garrett McElhenny; field of view 1.15 mm.
The Carlsbad laboratory recently examined a 0.70 ct, E-color round brilliant. Infrared spectroscopy showed this to be a type IIa diamond, so we performed a variety of additional spectroscopy and imaging to verify its natural origin. This diamond also had I1 clarity due to a large inclusion under the table (figure 1). Raman analysis of the inclusions verified that this crystal was a metastable composite of the minerals wollastonite (CaSiO3) and CaSiO3-breyite (E.M. Smith et al., “The very deep origin of the world’s biggest diamonds,” Winter 2017 G&G, pp. 388–403), which indicates a sublithospheric origin. These minerals are believed to be the lower-pressure phases of CaSiO3-perovskite. Around these minerals were large disk-like graphitic fractures indicating inclusion expansion as pressures on the diamond reduced during exhumation from the mantle. The other inclusion present was unidentifiable due to its graphitic casing. Recent research of inclusions in other type II diamonds shows that many, if not most, have a superdeep origin (again, see Smith et al., 2017). This stone is one more example of diamonds forming at incredible depths of 360–750 km before being transported to near the surface.

Figure 2. This DiamondView fluorescence image of the table and crown facets shows green fluorescence halos around two cavity features (as indicated by the red arrows). The green fluorescence, caused by the H4 defect, was caused by localized radiation within those cavities while the diamond resided within the earth’s crust and was exposed to radioactive fluids.
But even after such a tumultuous journey, the earth was not finished writing the story of this diamond. While in the earth’s crust, the diamond was exposed to radioactive fluids, particularly in etch channels now in the form of cavities on the table and crown facets. DiamondView imaging revealed fluorescing green halos around these cavities (figure 2). Although these isolated areas of fluorescence around the cavities indicated they had likely been filled with a radioactive fluid, there was none of the greenish color or radiation staining that would likely accompany higher radiation doses.

Photoluminescence (PL) mapping with 532 nm (figure 3) and 455 nm (figure 4) excitation shows a pronounced increase in radiation-related defects such as GR1, 3H, and TR12 and other vacancy-related peaks such as NV–, NV0, and H4 (a B aggregate with an additional vacancy) within these cavities (figures 3 and 4). Although this diamond was type IIa, there was sufficient nitrogen to form related defects that could be observed at the lower level of detection of PL spectra.

Figure 3. Left: A 532 nm PL map of the top cavity pictured in figure 2 shows a false-color image of GR1 intensity, revealing much higher concentrations along the perimeter of the cavity. Right: A plot of calculated concentrations for several vacancy-related centers from the PL map at left and collected at 3 μm intervals along the red line in the left image. The plot shows the elevated concentrations along the cavity edges of GR1 (neutral vacancy; zero-phonon line [ZPL] at 741.2 nm), NV0 (ZPL at 575 nm), and NV– (ZPL at 637 nm).

Figure 4. A photomicrograph (top left) of the lower cavity pictured in figure 2 is also shown in a 455 nm PL map (top right) displaying a false-color image of the H4 intensity. The corresponding spectra (bottom) for two points from the red and blue color regions are shown. Although the spectra were collected at only ~50 μm distance, there are pronounced differences in peak intensities. The diamond Raman peaks within the two spectra are scaled as equal. Photomicrograph by Sally Eaton-Magana.
A number of other peaks often seen in natural diamonds but not yet identified, such as those at 490.7, 498, and 505 nm, also showed elevated concentrations in these cavities; their enhanced presence due to natural radiation was consistent with prior observations (I.A. Dobrinets et al., HPHT-Treated Diamonds: Diamonds Forever, 2013, Springer). The width of the fluorescence halos in figure 2 and the elevated GR1 shown in figure 3 is approximately 30 μm, consistent with the penetration depth of alpha radiation (S. Eaton-Magaña and K.S. Moe, “Temperature effects on radiation stains in natural diamonds,” Diamond and Related Materials, Vol. 64, 2016, pp. 130–142). We know this radioactive fluid exposure must have occurred in the crustal region because many of the features, such as 3H, would not survive if this exposure occurred at greater depths and, therefore, higher temperatures.
These localized effects of radiation are particularly interesting because the dose was low enough to not impart green coloration or green to brown radiation stains. Nevertheless, the radioactive fluids left their mark on this diamond with the green fluorescence halos around the cavities, providing an excellent example of how many peaks are enhanced by radiation compared with the unaffected portions within the remainder of the diamond. It is also interesting that two distinctly different geological conditions and depths within the earth both contributed to the gemological characteristics of this diamond. The sublithospheric depths imparted some notable minerals as evidence of its superdeep formation, and radioactive fluids within the shallow, crustal region of the earth created the green-fluorescing halos and other radiation features. @chapter:39 @chapter:1 @chapter:39


# Publication Year: 2013
# Title: Major Crocoite Discoveries at the Adelaide Mine, Tasmania
# Abstract: Crocoite, first discovered in the Urals in 1766, was named crocoise in 1832. Its attractive orange-red hue and adamantine to vitreous luster make it one of the most pursued mineral collector specimens. Tasmania, located southeast of mainland Australia, has long been famous for its outstanding crocoite specimens, and nearly all commercial specimens come from the Red Lead and Adelaide mines.

The mines lie within a four-square-kilometer area. Cambrian intrusions of serpentinite within the Precambrian and slightly younger metasedimentary rocks provided the Cr needed to form crocoite. During the Devonian, metal-rich granitic intrusions provided hydrothermal fluids along the extensive shear zones to alter much of the serpentinite to a peculiar rock called listwanite and precipitate pods with veins of Pb-bearing minerals. Since crocoite is more stable than other Pb-bearing minerals at low pH levels, it predominated in these mines. Crocoite was common in the gossan, but open pockets yielded the best samples.

The earliest discovery of crocoite in Tasmania dates back to 1891. Over the last 120 years, it has been mined intermittently at several localities. Until the 1970s, many of the high-quality specimens were either destroyed or used for industrial applications. In 1970, “crocoite king” Frank Mihajlowits leased the Adelaide mine and began a string of major discoveries. Among these was a watercourse discovered in 1990 that was worked on for 14 years and yielded thousands of superb specimens.

In 2004, Mihajlowits sold the mine to Adam Wright’s newly established Adelaide Mining Company, which continues to work the deposit. A major new pocket of crocoite found in 2012 was of great excitement to mineral collectors. The opening of this watercourse is about one meter wide and two meters tall. Crocoite crystals of various lengths protrude at different angles to each other. This discovery is called the “Red River find,” and the watercourse has been broken into from below with no end to the channel found as yet. Many of these superb specimens were exhibited at the 2012 Tucson show.

Abstracted by Tao Hsu @chapter:6 @chapter:0 @chapter:6