Title: Montana Yogo Sapphires’ Unique Gemology Abstract: This suite of rough and cut Yogo sapphires shows the wide range of blue to violet or purple hues and light to dark saturation combinations that can be found in Yogo sapphires. The largest faceted stone is a 1.44 ct cushion cut. Courtesy of Bill Vance. Photo by Kevin Schumacher

Despite its Atlantic-to-Pacific land mass, the United States never has been known as a major source for gemstones. The one exception has been sapphire, though the story of Montana sapphires always has been obscured by more exotic locations.
Montana has been an important source of blue sapphire off and on since the 1890s and have unique gemological properties that distinguish them from those mined in other locations around the world, including Kashmir, Myanmar, Sri Lanka and Australia. GIA researchers Nathan D. Renfro, Aaron C. Palke, along with Richard B. Berg of the Montana Bureau of Mines, conducted an extensive analysis of gems from the Yogo Gulch deposit, reporting their findings in Gems & Gemology’s Summer 2018 issue.

The flat tabular shape of the Yogo rough often dictates the production of stones under 1 ct in weight. Photo by Robison McMurtry.
Yogo sapphires’ chief trait is that many of them have an attractive violet to blue color coming out of the ground and are generally not heat treated – the gem-quality stones rarely, if ever, respond to treatments. In addition, the color is generally evenly spread throughout the stones, so they lack the zoning that can be common in sapphires from other locales. Unfortunately, nearly all of the rough crystals are flat, tabular pieces that can only be cut into small gems. Thus, carat-plus sapphires from this source are quite rare.
Deeper gemological examination found that Yogo stones are unique in other ways as well. Most blue sapphires contain tiny needle-like or “silk” rutile inclusions. In the case of the classic Kashmir stones, for example, the clusters of near microscopic rutile impart a velvety glow to the gem, making them highly prized, with price premiums to match, for more than a century. This silk also can be a distracting clarity characteristic of some sapphires at times and heat treatment is relied upon to improve their clarity and color. On the other hand, Yogo sapphires rarely contain fine, needle-like rutile silk which was found in only one of the samples examined.

Rutile crystals can be seen as elongated rods with a dark brownish green color, left, and as black opaque rounded crystals with tension cracks and healed fringes that result from the igneous growth environment, right, and not from heat treatment. Photomicrographs by Nathan Renfro
Inclusions are often the most tell-tale signatures of a gem’s origin and Yogo’s primary signs are stress halos that surround very small pieces of other minerals trapped inside the still-forming sapphire. The halos (also called decrepitation halos) were formed when the mineral inclusions expanded inside the sapphire during its formation and caused tiny stress fractures. Other common, but distinctive inclusions are negative crystals – very small hollow areas filled with other materials.
Even deeper examination found that Yogo sapphires have a distinct trace element signatures with specific values of manganese, chromium, titanium, iron and gallium that are different from other sapphires.
While Yogo sapphires, and most other sapphires emanating from Montana, have an attractive natural blue color that commands premium prices, their small sizes and the complexities of working the deposits made it economically difficult to mine them.

This suite contains more than 36 carats of Yogo sapphires. Courtesy of Edward Boehm. Photo by Robert Weldon/GIA
The first Yogo source was discovered in 1895 and by the turn of the century, production averaged 400,000 carats a year. About 25% were gem quality and the remainder industrial goods used in watch movements and abrasives. This mine, sometimes referred to as the English Mine, operated until 1929. In 1910, it yielded the largest sapphire ever found in that locale, a 19 ct rough that was cut into four gems, the largest 8.5 cts.
The mine site is located within a long dike (a geological formation of volcanic rock layered above older, pre-existing rock) that held other sapphire deposits. Three other mines went into operation but, by the late 1920s, competition from synthetic sapphires for watch movements and abrasives, coupled with a disastrous flood and declining yields, made mining unprofitable.
The area remained abandoned for nearly 30 years before a group of investors renewed mining activities in 1956, but were unsuccessful. Several other failed attempts to revive mining at Yogo Gulch were made until 1980, when a mining engineer named Harry Bullock acquired the mining operations for $6 million and set out on a well-publicized effort to mine and market “Royal American Sapphires” under the corporate name Intergem. After some initial success, competition from inexpensive heat-treated Sri Lankan sapphires, mounting debts and increased mining costs sank the venture in 1985.

With activities resuming at Yogo Gulch, the industry may see more contemporary jewelry designs using the deposit’s sapphires. The suite shown here incorporates the blue material that made Yogo famous, along with the purple stones that remain a rarity. The center stone of the ring weighs 1.36 ct. Courtesy of Bill Vance. Photo by Kevin Schumacher
That year, prospectors found a new deposit in the southwestern tip of the dike. They called it the Vortex Mine and produced about 45,000 carats of cuttable rough a year, but closed in 2004. The following year, a miner named Mike Roberts took a part ownership of Vortex and successfully mined it on a small scale until he was killed in a mine site accident in 2012.
New owners are trying yet again to resume mining the Yogo Gulch and have been working on making necessary improvements to bring the mine back into production.
This research project, Renfo and Palke noted, “was a few years in the making.” One motivating factor for the study was the demand for Yogo origin, instead of the more general USA (Montana) notation on GIA lab reports.
A second factor, Renfro said, was that there was a “hole in the literature. Previous publications generally focused only on the geology (of the Yogo area), but there was no thorough gemological characterization of the material.”
And a third motivation was, “I just like Yogo sapphires,” he said.
Nathan Renfro completed his undergraduate studies in geology in 2006 and enrolled in GIA’s resident Graduate Gemologist (GG) program as a recipient of the William Goldberg Diamond Corporation scholarship. Renfro also completed his FGA in 2014. After finishing the GG program, he was hired by the GIA laboratory as a diamond grader and soon transferred to the Gem Identification department in 2008. Since then, Renfro has authored or co-authored more than 100 gemological articles and lectured to several gem and mineral groups throughout the U.S. His primary areas of gemological interest are inclusion identification and photomicrography, gemstone cutting and defect chemistry of corundum. Renfro is manager of the Gem Identification department and also is a microscopist in the Inclusion Research department. He is also the editor of the “Microworld” column in Gems & Gemology and a member of the editorial review board.
Dr. Aaron Palke started his career in gemology as a postdoctoral research associate at GIA after earning his Ph.D. in Geology from Stanford University. During this time, Palke investigated the geological history of rubies and sapphires by studying minute inclusions in these precious gems. A senior research scientist at GIA, he helps lead colored stone research efforts in order to provide more reliable country of origin determinations and treatment identification for rubies, sapphire, emeralds and other colored stones. See Palke's profiles on ResearchGate and Google Scholar. Source: GIA @topic:1


Title: Dual-Color Double Chatoyancy in Emerald Abstract: Figure 1. The emerald in this ring displays dual-color light green and white double chatoyancy. The stone measures 8.39 × 5.71 × 4.22 mm. Photo by Momo Matsumura.

Figure 2. Side view of the emerald ring. Parallel tube inclusions are oblique to the pavilion. The white reflection on the right is caused by the inclusions near the surface of the curved cabochon, while the greenish reflection on the left is caused by the reflection off of the bottom face of the cabochon. Photo by Shunsuke Nagai.
GIA’s Tokyo laboratory recently received for origin service a ring with an emerald displaying dual-color double chatoyancy (figure 1). One band showed white chatoyancy, while the other exhibited greenish chatoyancy similar to the bodycolor. The emerald had an oval double-cabochon shape with a polished crown and pavilion and contained parallel tubes slightly oblique to the polished pavilion, resulting in semitransparency. The dual-color double chatoyancy was caused by the same mechanism identified in dual-color star corundum and quartz by Schmetzer et al. (“Dual-color double stars in ruby, sapphire, and quartz: Cause and historical account,” Summer 2015 G&G, pp. 112–143). The white chatoyancy was caused by the linear reflection of the parallel tube inclusions from the upper cabochon surface. The greenish chatoyancy was caused by the linear reflection of the polished curved base through the interior of the stone to the surface (figure 2). Double chatoyancy is occasionally observed, but it is rare to find a very clear example of dual-color double chatoyancy. Source: GIA @topic:3


Title: Ruby and Sapphire from Jegdalek, Afghanistan Abstract: This study provides detailed mining and gemological information on the Jegdalek deposit, in east-central Afghanistan, which is hosted by elongate beds of corundum-bearing marble. Some facet-grade ruby has been recovered, but most of the material consists of semitransparent pink sapphire of cabochon or carving quality. The most common internal features are dense concentrations of healed and nonhealed fracture planes and lamellar twin planes. Color zoning is common, and calcite, apatite, zircon, mica, iron sulfide minerals, graphite, rutile, aluminum hydroxide, and other minerals are also present in some samples. Although the reserves appear to be large, future potential will depend on the establishment of a stable government and the introduction of modern mining and exploration techniques. Source: GIA @topic:1


Title: Sapphire Description Abstract: Sapphire comes in a variety of colors. This rare 1,126.00-ct. corundum crystal’s pinkish orange color is called padparadscha, named after the lotus flower. - © GIA & Tino Hammid

                      Blue sapphire belongs to the mineral species corundum. It can be a pure blue but ranges from greenish blue to violetish blue. The name “sapphire” can also apply to any corundum that’s not red and doesn’t qualify as ruby, another corundum variety.

	Deep, intense, velvety blue is the best way to describe the color of this sapphire from the Kashmir region on the India/Pakistan border. - Courtesy Edward Boehm, JOEB Enterprises, Chattanooga, Tennessee

	Most people who think of sapphire picture the color blue. - Courtesy Bulgari
Besides blue sapphire and ruby, the corundum family also includes so-called “fancy sapphires.” They come in violet, green, yellow, orange, pink, purple, and intermediate hues. There are also “parti-colored” sapphires that show combinations of different colors. Some stones exhibit the phenomenon known as color change, most often going from blue in daylight or fluorescent lighting to purple under incandescent light. Sapphires can even be gray, black, or brown.

	Stunning jewelry designs can be created by combining different sapphire colors.
	- Jeff Scovil
Fancy sapphires are generally less available than blue ones, and some colors are scarce, especially in very small or very large sizes. Still, fancy sapphires create a rainbow of options for people who like the romance associated with this gem, but who also want something out of the ordinary.

	Sapphires come in every color except red. Red corundum earns the name “ruby.” - Courtesy Omi Gems, Inc. Los Angeles, CA, USA
The mineral corundum is composed only of aluminum and oxygen, and it requires a growth environment that’s free of silicon. However, silicon is a very common element, making natural corundum relatively uncommon. In its purest state, corundum is actually colorless. Colorless sapphires were once popular diamond imitations, and they’ve staged a comeback as accent stones in recent years.

But colorless corundum is rare. Most corundum contains color-causing trace elements. When the trace elements are iron and titanium, the corundum is blue sapphire. Only a few hundredths of a percent of iron and titanium can cause the color, and the more iron the corundum contains, the darker the blue. Chromium can cause the red color of ruby or the pink of pink sapphire.

In the 1990s, discoveries in East Africa and Madagascar brought fancy sapphires widespread recognition. The new sources supplemented production from traditional ones like Sri Lanka and Madagascar and increased the availability of yellows, oranges, pinks, and purples.

The colors attracted jewelry designers who wanted to move away from traditional hues of red, blue, and green. Now, contemporary designers arrange fancy sapphires in stunning rainbow suites.

Corundum can show a phenomenon called asterism, or the star effect. This phenomenon usually appears as a six-ray star pattern across a cabochon-cut stone’s curved surface. The star effect can be seen in ruby or any color of sapphire, and it arises from white light reflecting from numerous tiny, oriented needle-like inclusions.

Besides fancy sapphire and star corundum, there’s another interesting variety: color-change sapphire. These fascinating stones change color under different lighting. Their presence adds a special dimension to the already amazing corundum family of gems.

Both blue and fancy sapphires come from a variety of exotic sources including Madagascar, Tanzania, Sri Lanka, Myanmar, and Australia. Source: GIA @topic:1


Title: Jadeite of Guatemala: A Contemporary View Abstract: Although lost for literally hundreds of years after the Spanish conquest of the Aztecs, many deposits of jadeite have been found in Guatemala during the last two decades. Following the discovery of the first significant outcrop in 1974, literally tons of jadeite in a wide variety of colors have been removed from the area and sent to cutting shops for use in tourist carvings, in fine reproductions of Indian artifacts, and in jewelry. Source: GIA @topic:12


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

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

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

	Warren Boyd – Potentate Mining LLC

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

Figure 2. As displayed by these rough and cut sapphires, Potentate’s sapphire
production includes a wide variety of colors. Photo by Eric Welch/GIA, courtesy of
Potentate Mining. Source: GIA @topic:1


Title: Jewels from Imperial St. Petersburg Abstract: Geared toward the jewelry historian, this thoroughly researched work is a window into the world of the Russian imperial Romanovs, starting with the reign of Empress Elizabeth (1741–1762), and ending with Nicholas II in 1917. The author details in chronological order the jewelry and objects d’art manufactured in St. Petersburg during this period. The book contains numerous photos of the jewels and family portraits from that era.

Reviewed by GIA Library Staff
Carlsbad, California Source: GIA @topic:6


Title: Update on Mozambique Ruby Mining and Trading Abstract: Figure 1. The main ruby mining areas of northern Mozambique. Those labeled in red are worked by Gemfields, and those in yellow by Mustang Resources. Green, pink, and blue areas are worked by garimpeiros; the green areas show where they are allowed to mine. Pink and blue represent sites inside MRM and Mozambican Ruby, respectively.
Less than 10 years after discoveries inside the Niassa Reserve in 2008 and near Montepuez in 2009, rubies from northern Mozambique have taken a significant place in the trade. During the first few years, production came exclusively from unlicensed miners known as garimpeiros, who sold their production mainly to Thai, Sri Lankan, Tanzanian, and West African traders. The stones were smuggled to cutting and trading centers such as Thailand. The situation changed when Gemfields, which acquired mining licenses near Montepuez in 2011 and began operations in 2012, held its first rough ruby auction in Singapore in June 2014.

Since 2015, three factors have affected that dynamic, starting with an efficient low-temperature heat treatment technique developed in Sri Lanka and brought to Mozambique. As the treatment is very difficult to detect without lab instrumentation on faceted stones and even more so on rough, the challenge for dealers buying stones from garimpeiros was to avoid paying unheated ruby prices for stones that had been already heated. Many buyers purchased heated rough in Montepuez only to find out later in Thailand about their costly mistake. Within a few months, confidence in the stones from that network deteriorated and dealers found out that the only safe options for unheated rubies were to buy directly from Gemfields or to get reliable laboratory testing on any stones obtained elsewhere. The situation became difficult for those willing to take their chances buying illegally in Mozambique.

In early 2016, another significant change took place when the Mozambican government changed its policy on garimpeiros. Before 2016 the garimpeiros were, legally speaking, “informal” small-scale miners. The only legal issue was that they had no license. The police were only allowed to confiscate their mining equipment and question them before releasing them. But in 2016, mining for gemstones or gold without a license became a crime punishable by three years in jail. In February 2017 the government, which was facing major fiscal problems, changed tactics: Instead of taking legal action against garimpeiros, they would target buyers hiding in the towns. Several police operations were launched in Cabo Delgado, and many foreign buyers (mainly Tanzanian, Thai, Sri Lankan, and West African) were arrested, fined, and expelled. Rubies quickly became more scarce in the Thai markets. This probably explains why Gemfields had its most successful ruby auction ever in June 2017, recording more than US$54 million in sales.

Finally, as previously reported (W. Vertriest and V. Pardieu, “Update on mining in northern Mozambique,” Winter 2016 G&G, pp. 404–409), two new mining companies, Mustang Resources and then Mozambican Ruby (formerly known as Metals of Africa), began operations near Napula village, north of the road linking Montepuez to Pemba in areas neighboring Gemfields. As these companies have not yet sold any production, their impact is still unknown.

In June 2017, the author visited northern Mozambique (figure 1) for the sixth consecutive year to collect reference samples. This time it was for Danat, the newly formed Bahrain Institute for Pearls & Gemstones. The team was composed of jewelry designer Erica Courtney; Dr. Cedric Simonet, a geologist with extensive experience in East African gem deposits; and a photographer and videographer.

Unlike previous years, we visited the area at an early stage of the dry season, which extends from June to November. The land was still green, and upon arriving we were struck by the lack of activity at the main garimpeiro villages on the road between Pemba and Montepuez. While in previous years we could see thousands of people and hundreds of shops at Nanupiu and Namahumbire, this time there were maybe a few hundred people in the streets and most of the shops were closed. It seemed that most of the garimpeiros had moved to other parts of the country.

MRM (Montepuez Ruby Mining): Our visit to the MRM mine, owned by Gemfields and its local partner Mwiriti Limitada, took place during the record-breaking ruby auction in Singapore and a few days after Pallinghurst, Gemfields’ main shareholder, attempted a takeover. We also saw representatives from the Chinese conglomerate Fosun, which was also looking to acquire Gemfields. The mine staff was thrilled by the results of the Singapore auction but uncertain about Gemfields’ future. Afterward we learned that Pallinghurst was successful in the takeover. Gemfields was delisted from the London Stock Exchange on July 28, and a few days later Gemfields CEO Ian Harebottle announced his resignation. He was replaced by Sean Gilbertson.

Besides the excitement about the auction and the legitimate questions about the future of Gemfields, we observed some interesting changes at MRM. First, MRM continued to improve its mining and sorting capacity. Figure 2 shows a dense media separation (DMS) plant that became operational in December 2016, replacing the previous system of pulsating jigs. The results were said to be very encouraging, particularly regarding small material. Before, all material under 3 mm was rejected and stockpiled. With the new DMS plant, rubies under 3 mm can be collected very efficiently, and MRM’s washing capacity has increased from 80 to about 150 tons per hour in ideal conditions. The sorting house scheduled to go next to the new DMS plant in 2017 will not be completed before summer 2018. Visiting the existing sorting house, we saw few improvements in rough processing efficiency. The author was able to once again select samples from recent production. These were mainly high-clarity, attractive rubies from the classic Mugloto/Machamba area, which has produced most of the stones auctioned by Gemfields since 2014.

Figure 2. An aerial view of MRM’s new ruby washing plant, which uses dense media separation. Photo courtesy of Gemfields.
Exploration continues, meanwhile, and mining is being planned for new areas east and west of the current pits at Mugloto/Machamba (producing secondary-type, iron-rich material with high clarity) or Maninge Nice (producing primary-type stones with moderate iron content and more inclusions and fractures). Glass, a secondary deposit south of Maninge Nice, was not bringing as much as expected, as it had been extensively worked by garimpeiros since 2009.

In summer 2017, the MRM mine employed 450 people. Including security and contractors, that number is more than 1,100 employees. Concrete houses have replaced the cargo containers once used as living quarters, and life there is now much more comfortable. Since the construction of the main camp, MRM has been able to focus on corporate social responsibility, and we could see significant results that have improved MRM’s image in local communities. The company has built schools at Namahumbire and Nseve. We saw two chicken farms that appeared to be sustainable, and six farming associations created and supported by Gemfields. At Nseve, we visited a farming pilot program that could become very successful, as the area was fertile during Portuguese colonial times when the nearby reservoir was built. Agriculture disappeared after the civil war, which destroyed the local communities and the economy. MRM is also financing a mobile health clinic, enabling government doctors to visit different villages each day to serve those with little access to health care. Finally, we could see that Gemfields was continuing to support conservation and community development in the Niassa Reserve with the “Niassa Lion” project.

Mustang Resources: In 2016, the author reported on the emergence of Mustang Resources, which acquired mining licenses in 2015. At the time they were focused on exploration and camp infrastructure. Mustang has been quite active, and the operation now employs about 130 people. A modern washing plant using rotary plants (figure 3) is in place. Jigs (the small “Bushman jig” version used for prospecting) and a small sorting house have been built. Mustang decided to concentrate on LP01, a promising area in the south of the concession where gem-rich gravels could be found at less than one meter depth. Operating at such shallow depth is inexpensive, as there is little overburden to be removed. The area had been discovered by garimpeiros (figure 4), and we saw mining from both Mustang and local villagers.

Figure 3. Mustang Resources’ new washing plant consists of two rotary pans equipped with trammel screens and log washers. Its current capacity is about 600 tons per day. Photo by Vincent Pardieu.

Figure 4. A garimpeiro working near the LP01 pit inside Mustang Resources’ concession near Napula village excavates the ruby-rich gravel under the topsoil. Photo by Vincent Pardieu.
The stones are similar to those found in Glass or around Nacaca village (an area open for garimpeiros to the east of the Gemfields concession). This means that these are mainly secondary-type rubies that spent millions of years in gravels and show some abrasion. They have a fine pink to deep red color and are quite clean with rare fractures, but they tend to be smaller and their color is brighter than the production at Mugloto/Machamba, which has a higher iron content. We saw several fine clean rough stones up to 10 carats, but most of the production was under 1 carat.

We were informed that Mustang planned to have its first rough ruby auction at the end of November 2017 in Mauritius, as several tens of kilos had already been mined.

Mozambican Ruby Lda.: While significant changes were visible in areas worked by Mustang and MRM, the same could not be said for Mozambican Ruby Lda. The project was clearly still in an early stage, with only a few employees and very basic equipment. The exploration program has nevertheless advanced considerably since last year, and more equipment is expected to arrive this year. The project is led by a small private company with a rather cautious approach. We visited the different pits mined by garimpeiros during the author’s previous visit in 2016. The two pits at Castro were flooded and mainly being used by garimpeiros as a water reserve for washing the gravel they collected around the pit. The area seems to have great potential.

Our visit to the Montepuez area showed the evolution of ruby mining by MRM, Mustang, and Mozambican Ruby Lda., as well as by the garimpeiros. It now seems that the legally operating mining companies are gaining the upper hand over the garimpeiros and the foreign buyers who smuggle stones to trading centers in Tanzania, Sri Lanka, and Thailand. It will be interesting to see what happens with Gemfields under Pallinghurst’s full control and the impact of forthcoming production from Mustang. Source: GIA @topic:7


Title: A Season of Thanks for Dedicated Alumni Members Abstract: A new Macau chapter launched in September with a big celebration. Courtesy of GIA Alumni Macau Chapter

	Though the end of the year is on near horizon, December is never a time to slow down in our industry. There’s a month of sales, service, preparing special orders and even getting ready for our important tradeshows at the start of the new year. In all of the chaos, however, I most appreciate the times we take to share our thanks and celebrate with our industry family – as well as our families and friends.

	The positive spirit that is so often seen and shared this season is contagious, so in that spirit I’d like to share my appreciation for you, my fellow GIA Alumni Association members.

	First, I want to thank the more than 200 alumni volunteers who work tirelessly throughout the year to coordinate valuable education and networking events for GIA Alumni chapters around the globe. The actions of these individuals directly help GIA serve its mission, by creating opportunities to deliver education, grow business relationships in their communities and provide a resource for like-minded professionals to come together in a shared effort to promote the integrity that is a cornerstone of the gem and jewelry industry. All of these actions serve to protect the buying public, the underlying goal of all of GIA’s work.

	Second, I want to thank every individual and organization that has shared their time and expertise with our chapters. Your generosity enhances the knowledge of others and pays it forward.

	Lastly, I applaud the loyal alumni and industry members who are committed to staying up to date on their gemological education. Attending GIA global alumni events and lectures, as well as reading gemological updates and news that affects our industry, improves your craft and makes it possible for you to act as stewards, ensuring a positive future of an industry where reputation is vital.

	Before the end of 2016, our chapters will have hosted more than 200 events. I could not be more appreciative of the actions of the committed individuals who have shared the responsibilities to make these GIA Alumni events a success. Take a quick look at the more than 50 chapter events hosted by GIA Alumni Association chapters since September. You just may find a great idea for your next meeting.

	Alumni News

Party at the GIA Gem Mine: Cosmic Blast. Preparations are in full swing and the deadline of Dec. 31 to donate to the auction is weeks away. Tickets are selling fast – we hope to see you there!

GIA 2016 Continuing Education Recognition Program participants – don’t forget to complete your eight lessons before Dec. 31 to be qualified to receive your credential.

GIA’s Education Scholarship application period ended on Sept. 30 and more than 1,000 applications were received. Scholarship recipients will be notified shortly, offering more than 100 individuals GIA education opportunities around the globe. GIA accepts applications for scholarships two times each year, so get ready for the next application period, which is open Feb. 1 to March 31, 2017.

GIA’s Bev Hori presents the latest news on synthetic diamonds to the Seattle chapter. Courtesy of GIA Alumni Seattle Chapter

	Chapter Activities

		A new chapter launched in Macau in September with a welcome presentation by GIA’s Dr. Wuyi Wang, director of research and development, who spoke on synthetic diamonds. The evening was also attended by additional GIA executive leadership, including Susan Jacques, president and CEO; Tom Moses, executive vice president and chief lab and research officer; Anna Martin, senior vice president of global development; and Seung-Hae Moon, managing director of Asia-Pacific education. Alumni from the new chapter and members of the Hong Kong alumni chapter attended.

		Bev Hori, senior vice president and chief learning officer, provided a market update and spotlight on synthetic diamonds in Seattle.

		Dr. James Shigley, distinguished research fellow, covered the latest news on research from GIA in Salt Lake City, Utah.

		John Koivula, analytical microscopist, shared a visual review educating attendees on treatments and synthetics – in Washington, D.C.

		Robert Weldon, manager of photography and visual communications, recounted his 2015 journey to Colombia, retracing the steps of explorer and miner Peter Rainier, who is credited with rediscovering the Chivor emerald mine in the 1920s, for the  San Diego  and London chapters. (See  Weldon’s article on the topic, which was featured in the Summer 2016 issue of Gems & Gemology.)

		Edward Johnson, director global business development in Europe, and I connected with European alumni at the Munich show and at a reception hosted by the Germany chapter in October.

		Synthetic diamonds in the jewelry market was discussed at seven chapter events in September. Gary Roskin, author, adjunct professor and executive director of International Colored Stone Association (ICA) spoke on the topic of identifying gem-quality synthetic diamonds to the New England and Washington, D.C. chapters.

		Hands-on gemological sessions remain popular continuing education event for our chapters, including identifying and evaluating Australian opals in London. Participating members of the Twin Cities chapter completed their three-session 2016 Year of Corundum study group.

London chapter board members posed with guest lecturer Debbie Good, second from left. From left: Eloise Matthieu, Good, Lubica Mictkova, Rocio Del Mar and Sharon Dale. Image courtesy of GIA Alumni London chapter

		Colored gemstone interest is extensive among chapters across the globe:

			Doug Hucker, CEO of the American Gem Trade Association, provided insight on how to sell more color with the Michigan members.

			Ron Ringsrud shared his decades of experience and expertise on Colombian emeralds at a Metro-Phoenix meeting.

			Evan Caplan, procurer of rare and exotic fine gemstones, educated Golden Gate chapter attendees with a talk on alexandrite, including sources, pricing, trends and identification.

			Gemstone dealer Brian Cook presented the “Thrill of Brazil” at events in Houston and California Golden Gate.

			Renee Newman, a noted author and lecturer, shared the rarity and market opportunities related to exotic gemstones at a North Carolina event.

			Chapter leaders provided an overview of ruby to attendees in Monterrey, Mexico.

Michigan chapter members donned blue protective blue gloves so they could inspect coin, jewelry and ornamental artifacts on their Kelsey Museum tour. Courtesy of GIA Alumni Michigan Chapter

		Pearls and other organic gem materials were presented by Eric Fritz at Florida Gulf Coast.

		An exclusive “pre” preview of the Contemporary Designer Jewels Signature Auction, featured at Heritage Auction House, was experienced by our alums before the general public had the opportunity to see it in Los Angeles.

		Jewelry pricing and history were points of interest in several chapters, including international auction house diamond prices in Mexico City and the history of the wedding ring at California Golden Gate.

		Photography tips were the topic presented by renowned mineral photographer, Jeff Scovil, at Colorado Mile High.

		Lapidary interests were covered by award-winning gemstone cutters and artists Naomi Sarna and Dalan Hargrave (both multi-award winners of AGTA Spectrum awards) in Houston and Manhattan. Famed Idar-Oberstein gemstone carver Patrick Dreher, of the House of Dreher, shared history and the craft of his family, which dates back five generations, at a San Diego event.

		The fourth and final segment of the film documentary “Masters of Dreams” completed the chapter’s Gema Cinema series in Monterrey, Mexico.

		A tour and visit to Kelsey Museum of Archaeology provided a special opportunity for a hands-on inspection of a selection of exhibit objects, including coins, jewelry and other ancient precious metals, for Michigan chapter members.

		A mine tour excursion to the Oceanview Mine was cohosted by the San Diego and Los Angeles chapters.

		An Illinois/Indiana road trip to the largest showroom of gemstone beads in the Midwest included a lecture on the value of staying current with gemological education and understanding quality and pricing.

		Local networking socials were successful in Georgia, North Carolina, Vancouver, London, Malaysia, Toronto and California Golden Gate. Sri Lanka hosted members from Malaysia and Taiwan, and San Diego welcomed folks visiting Southern California for GIA’s Gem and Jewelry Career Fair, in Carlsbad.

The Sri Lanka chapter hosted members from Taiwan and Malaysia for alumni events during the Facets Show held in Colombo, Sri Lanka. Courtesy of GIA Alumni Sri Lanka Chapter

	I wish all our alumni a very happy and successful year end and encourage you to stay in touch with GIA through the alumni department. There are new changes coming in the New Year and we want you to make the most of the advantages and benefits available to you. Source: GIA @topic:9


Title: Chromite in Emerald Abstract: A Brazilian emerald with green color zoning and strong graining surrounding clusters of chromite. Photomicrograph by Nicole Ahline; field of view 1.58 mm.

The beryl species is known for its different colored varieties, such as pink morganite and blue aquamarine, which are directly influenced by the chemical composition of the stone. The emerald variety is colored green by the trace elements chromium and/or vanadium. Beryl, a beryllium aluminum cyclosilicate, has a crystal structure that readily integrates foreign elements. When an elevated amount of chromium is present in the growth environment, a beryl crystal has a chance of becoming an emerald. One inclusion that has been well documented in emeralds is the mineral chromite, an iron chromium oxide. Specifically, this mineral is a source of chromium for some Brazilian emeralds.
The author recently examined a matching jewelry set consisting of a bracelet and ring that were decorated with emeralds from Brazil. Each stone exhibited a unique concentration of color when viewed through diffused lighting. Compared to the angular or linear color zoning generally seen in emeralds, each of these stones displayed an irregular, circular green zone with strong graining. The color zoning correlated with crystallites of chromite (see above). During the emerald’s crystallization, chromite from the growth environment was incorporated into the stone as an inclusion. A chemical alteration along the interface of the chromite and the beryl occurred due to the presence of chromium from the crystallites. The altered chemistry of the beryl led to the green bodycolor adjacent to the chromite crystals. The strong graining is the result of the difference in refractive index in the green-colored area from the elevated chromium in contrast to the host beryl.
While chromite is regularly seen in emeralds from Brazil, it is not common to see such a strong correlation of color with the mineral inclusion. Source: GIA @topic:3


Title: Sapphire Series Part 3: Modern Synthetic Sapphire Applications Abstract: Previously we introduced sapphire as a gemstone and as a major industrial material that spurred the advancement of many synthetic crystal growth techniques. Synthetic sapphire is commonplace in our everyday lives, as its desirable properties—optical, mechanical, thermal, chemical, and structural—have yielded an array of fascinating applications.

	Figure 1. For the past 25 years, titanium-doped synthetic sapphire crystals for high-
	power lasers have been grown using the heat exchanger method. Courtesy of GT
	Advanced Technologies.
A turning point for synthetic sapphire was the invention of the laser in 1960. Theodore Maiman, using a Verneuil-grown ruby crystal fashioned into a rod, demonstrated the first optical laser. The quality of ruby from flame-fusion growth was inadequate for commercial lasers, prompting the synthesis of sapphire using the Czochralski technique. To this day, laser crystals of a variety of compositions are still grown this way. Ruby crystals, traditionally grown for military range finders and cosmetics applications such as tattoo and hair removal, have largely been replaced by other laser materials. Ruby lasers are now mostly used for producing holographic images and drilling small holes in diamond.

Another significant laser crystal is titanium sapphire, often produced by the Czochralski technique or the heat exchanger method (figure 1). Titanium sapphire lasers, with their ability to produce extremely high-energy and ultra-short pulses (pico-, femto-, or even atto-second in duration), have been instrumental in advancing fundamental research and may hold the key to realizing nuclear fusion energy in the future.

	Figure 2. Sapphire windows are widely used in the aerospace industry. Courtesy of GT
	Advanced Technologies.
Once the ability to grow large chromium-doped ruby crystals was established, scientists began developing undoped synthetic sapphire (generally called “white sapphire” or “leucosapphire”) as a durable and highly transparent material. The 1960s saw the advent of low-defect crystals with high chemical purity used in protective laser coverings for the military, aerospace windows (figure 2), bulletproof armor, and various scratch-resistant surfaces. Sapphire, with its desirable insulation and structural properties, was a suitable substrate material for single-crystal semiconductors such as silicon (1963) and gallium nitride (1969). This opened up even more market opportunities, including faster and more energy-efficient circuitry, as in the Hewlett-Packard 41 series calculators developed in the 1970s. The technology also permitted shorter-wavelength light emitting diodes (LEDs) in blue, ultraviolet, and white. Sapphire substrates have grown considerably larger, to 10 inches in diameter (figure 3). Consumer applications of synthetic white sapphire eventually followed.

	Figure 3. Monocrystal’s 10-inch sapphire substrate is shown next to a 2-inch sapphire
	substrate. Courtesy of Monocrystal
We’ve all heard the familiar “beep” at the checkout counter when merchandise is slid across the scanner window next to the cash register. The top layer of that window is made of a very thin piece of sapphire, which keeps the glass free of scratches, allowing countless items to be dragged across it without the need for replacement. First developed in 1978 (figure 4), this application is now seen in retail outlets worldwide. Sapphire windows can also be used to protect biometric fingerprint sensors. There is speculation that smartphone companies may be interested in this technology, and that’s just the beginning of that industry’s synthetic sapphire possibilities.

	Figure 4. This photo shows the very first sapphire point-of-sale window prototype. Courtesy of Frank Bruni. To read more about this prototype, visit http://frankbruni.com/uncategorized/the-birth-of-the-sapphire-pos-terminal-window.
Sapphire has been used as a covering for cellphone camera lenses, and it is also being tested by smartphone and electronic tablet manufacturers for shatter-proof display screens (figure 5). Some very high-end smartphones already have sapphire touchscreens. If every smartphone built next year had a sapphire screen, approximately one billion finished sapphire screens would need to be produced. Consumer demand for a scratch- and crack-free screen is high, and various market players and industry analysts have found a consumer willingness to pay an additional $30 to $50 for this feature. Even so, current synthetic sapphire capacity may not be able to meet the demand.

	Figure 5. Blocks of synthetic sapphire were used to produce these smartphone display screens. Courtesy of GT Advanced Technologies.
Sapphire substrates are being used to produce the next generation of ambient lighting, white LEDs. The white LED is actually a blue LED (figure 6) coated with a yellow-emitting phosphor, a combination that produces white light. The future is bright for LED lighting as the world strives to be more energy efficient and less reliant on toxic elements such as mercury. The demand for substrate sapphire is very large—in the millions per year and growing—and there is competition for resources among manufacturers of synthetic sapphire for various applications.

	Figure 6. Blue, ultraviolet, and white LEDs are commonly grown on synthetic sapphire
	substrates. White LEDs are created by applying a phosphorescent coating such as
	cerium yttrium aluminum garnet to blue LEDs. Courtesy of GT Advanced Technologies.
So where does gemology fit into this? Sapphire occupies a sizeable percentage of the synthetic gemstone market. But even as demand for synthetic gem corundum increases, the portion of industrially grown sapphire crystals used as gem materials is shrinking. With technical applications for sapphire on the rise, the synthetic gem industry will continue to feel the effects in product quality, supply, and pricing—topics that will be further explored in the fourth and final installment of this series. Source: GIA @topic:3


Title: Spinel Journey Abstract: Few people outside the gem industry realize the true nature of a gemstone’s journey from the mine to the counter of a store. Whether the gem is being offered to consumer’s at a traditional jewelry store’s counter, an internet shopping site, or a television broadcast the journey always involves a great deal of effort.  Tons of earth and countless hours of labor are needed to being a gem from mine to market. Source: GIA @topic:7


Title: Sapphire Journey Abstract: Few people outside the gem industry realize the true nature of a gemstone’s journey from the mine to the counter of a store. Whether the gem is being offered to consumer’s at a traditional jewelry store’s counter, an internet shopping site, or a television broadcast the journey always involves a great deal of effort.  Tons of earth and countless hours of labor are needed to being a gem from mine to market. Source: GIA @topic:7


Title: Aquamarine Journey Abstract: Few people outside the gem industry realize the true nature of a gemstone’s journey from the mine to the counter of a store. Whether the gem is being offered to consumer’s at a traditional jewelry store’s counter, an internet shopping site, or a television broadcast the journey always involves a great deal of effort.  Tons of earth and countless hours of labor are needed to being a gem from mine to market. Source: GIA @topic:7


Title: Books: Kentucky Agate:State Rock and Mineral Treasure of the Commonwealth Abstract: By Ronald L. McIntosh and Warren H. Anderson, 216 pp., illus., publ., by University Press of Kentucky, Lexington, 2013, US$45.00.

              From rough found in the streambeds of Station Stamp Creek to finished jewelry, the story of Kentucky agates, the official rock of the Bluegrass State, is told in words and shown with beautiful images.

The adventure starts in the first chapter, which offers 10 examples of agate types with descriptive names such as plume, moss, cloud, and flame. The photo meant to show moss and dendritic agate is not a good example, though, as the image did not clearly resemble moss on a rock of the branches of a tree, as described.

Chapter 2 explores when and where to find agates, as well as places where collecting is not permitted, such as Daniel Boone National Forest or the Natural Bridge State Park and River Gorge Geological Area, both of them scenic and popular spaces. Maps and photos of these locations are provided. The chapter also provides the names of gem and mineral shows, both within and outside the state, where agates are sold, as well as Kentucky colleges and museums with collections that are open to the public.

The formation and geology of agates are covered in the next two chapters. Chapter 3 features 16 photos of polished material, with captions describing the incredible colors and unique features of each sample. Chapter 4 includes a geologic map of the area where most Kentucky agates are found, along with the origins of their beautiful colors and banded patterns.

Microscopic features are described and shown in chapter 5. Under magnification, the causes of the unique features are more easily seen, and the captions offer additional details. For example, page 40 features an agate with heart-shaped banding, yellow limonite, and red hematite spherical inclusions. Ten of the samples are shown in reflected light, two in transmitted light, and another two in both reflected and transmitted light. The differences in appearance are striking, though it is unfortunate that the captions don’t list the magnification used.

The highlight of the book is chapter 6, featuring 255 photographs of cut specimens and slices. There are no more than two agates per page for over 149 pages. The backgrounds have been removed from the photos so the agates are seen against the white page, which makes the beautiful colors, patterns, and features even more breathtaking.

The final chapter features 11 examples of agate jewelry, with a photo displaying various agate cabochons. There is a refreshing mix of the traditional belt buckles and bolo ties alongside some very modern designs. One notable example is a tie clasp featuring a freeform polished agate with bold, contrasting colored bands of red and gray/black designed and created by Rachel Savané. Additional works are listed in the bibliography for readers interested in more information.

In this volume, Ronald McIntosh and Warren Anderson bring together an amazing collection of agates, professionally photographed with high-quality printing, creating a greater level of appreciation for these natural works of art. Source: GIA @topic:7


Title: Drill Hole in Heated Pink Sapphire Abstract: Figure 1. A drill hole in a heated pink sapphire from Myanmar, seen with diffuse brightfield and fiber-optic illumination. Photomicrograph by E. Billie Hughes; approximate field of view 5 mm.

While testing a faceted pink sapphire in our laboratory, we looked at its internal features and determined that it was a heat-treated stone from Myanmar. As we examined the surface of the 14.75 × 13.02 × 8.82 mm sapphire, we noticed an unusual feature: a large round drill hole extending from the surface into a crystal or negative crystal within the stone (see above). Note that this drill hole did not extend through the sapphire, as one might see in a bead. This stone was faceted, so it is unlikely that the person who drilled into the stone intended to create a bead.
What seems more likely, given the placement of the drill hole, is that it was drilled to minimize the appearance of the crystal that it reached. We suspect that the crystal was originally more opaque and of darker color or filled with a dark substance. It is possible that the drill hole was created so that the crystal could be cleaned out with acid, minimizing its appearance. We can only guess at the intentions of the treater, who might have gotten the idea from the laser drilling of diamonds.
Although the exact process may remain a mystery, this inclusion indicates an unusual treatment in ruby and sapphire. Source: GIA @topic:3


Title: Books: Kentucky Agate: State Rock and Mineral Treasure of the Commonwealth Abstract: By Ronald L. McIntosh and Warren H. Anderson, 216 pp., illus., publ., by University Press of Kentucky, Lexington, 2013, US$45.00.

                      From rough found in the streambeds of Station Stamp Creek to finished jewelry, the story of Kentucky agates, the official rock of the Bluegrass State, is told in words and shown with beautiful images.

The adventure starts in the first chapter, which offers 10 examples of agate types with descriptive names such as plume, moss, cloud, and flame. The photo meant to show moss and dendritic agate is not a good example, though, as the image did not clearly resemble moss on a rock of the branches of a tree, as described.

Chapter 2 explores when and where to find agates, as well as places where collecting is not permitted, such as Daniel Boone National Forest or the Natural Bridge State Park and River Gorge Geological Area, both of them scenic and popular spaces. Maps and photos of these locations are provided. The chapter also provides the names of gem and mineral shows, both within and outside the state, where agates are sold, as well as Kentucky colleges and museums with collections that are open to the public.

The formation and geology of agates are covered in the next two chapters. Chapter 3 features 16 photos of polished material, with captions describing the incredible colors and unique features of each sample. Chapter 4 includes a geologic map of the area where most Kentucky agates are found, along with the origins of their beautiful colors and banded patterns.

Microscopic features are described and shown in chapter 5. Under magnification, the causes of the unique features are more easily seen, and the captions offer additional details. For example, page 40 features an agate with heart-shaped banding, yellow limonite, and red hematite spherical inclusions. Ten of the samples are shown in reflected light, two in transmitted light, and another two in both reflected and transmitted light. The differences in appearance are striking, though it is unfortunate that the captions don’t list the magnification used.

The highlight of the book is chapter 6, featuring 255 photographs of cut specimens and slices. There are no more than two agates per page for over 149 pages. The backgrounds have been removed from the photos so the agates are seen against the white page, which makes the beautiful colors, patterns, and features even more breathtaking.

The final chapter features 11 examples of agate jewelry, with a photo displaying various agate cabochons. There is a refreshing mix of the traditional belt buckles and bolo ties alongside some very modern designs. One notable example is a tie clasp featuring a freeform polished agate with bold, contrasting colored bands of red and gray/black designed and created by Rachel Savané. Additional works are listed in the bibliography for readers interested in more information.

In this volume, Ronald McIntosh and Warren Anderson bring together an amazing collection of agates, professionally photographed with high-quality printing, creating a greater level of appreciation for these natural works of art. Source: GIA @topic:7


Title: Pink Pyrope Garnet Abstract: A 7.26 ct modified round brilliant identified as pink pyrope garnet. Photo by Towfiq Ahmed; courtesy of Bill Vance.
The Carlsbad laboratory received a 7.26 ct pink modified round brilliant (see above) for a colored stone identification report. Standard gemological testing revealed that the stone was singly refractive with a refractive index (RI) of 1.741 and a hydrostatic specific gravity (SG) of 3.77, properties consistent with garnet. Internally the stone was quite clean, with microscopic examination revealing scattered short needles.
The garnet group is composed of more than 20 species, all of them sharing the basic chemical formula X3Y2(SiO4)3. Five of these species are common within the jewelry industry: almandine, andradite, grossular, pyrope, and spessartine. Andradite and grossular are ugrandite garnets; they have calcium in the X site of their chemical formula. Almandine, pyrope, and spessartine are all pyralspite garnets containing aluminum in the Y site. Isomorphous replacement, in which one chemical element substitutes for another in a mineral’s crystal structure, makes it possible for garnets to be a chemical mixture of two or more garnet species. GIA gemologists use a garnet’s gemological properties and chemistry to categorize the stone into its particular species.
Chemical analysis revealed that the 7.26 ct stone was a pyralspite garnet due to the high aluminum concentration (values expressed in wt.%: MgO 18.50%, Al2O3 23.05%, SiO2 41.32%, CaO 1.89%, TiO2 0.05%, V2O3 0.02%, Cr2O3 0.04%, MnO 11.93%, Fe2O3 3.17%). The composition of this garnet and its gemological properties were consistent with pyrope, which has an RI of 1.73–1.75, an SG of 3.78 (+0.009/–0.016), and magnesium dominating the X site and minor amounts of manganese and iron. Pyrope garnet, though, has a color range of red to reddish orange and colorless. Pink pyrope garnet is incredibly rare, especially in stones of this size.
Pyrope-spessartine can have a bodycolor similar to pyrope but has an RI range of 1.75 to over the limit and an SG of 3.78, both higher than the values documented for this pink garnet. The fact that garnet can be a mixture of species can make the identification of these stones challenging. This example is an important reminder to carefully analyze a garnet’s gemological properties to accurately identify it and how the laboratory can use chemical analyses as validation. Source: GIA @topic:3


Title: Polymer-Impregnated Aventurine Quartz, a New Imitation of “Ice Jade” Abstract: Figure 1. This light green semi-transparent bangle was made from polymer-impregnated aventurine quartz, a new imitation of “ice jade.” Photo courtesy of Lai Tai-An Gem Lab.

The market for jadeite jade is sizable, especially in the Far East. The variety and quantity of jadeite imitations is vast, a source of concern for the trade and consumers alike. A client recently submitted a polymer-impregnated aventurine quartz bangle to the Lai Tai-An Gem Lab in Taipei under the mistaken impression that it was jadeite jade.

The 212.90 ct bangle measured approximately 68 × 13 mm and exhibited a light green color, with a pleasant semi-transparent appearance that resembled a type of jadeite often referred to as “ice jade” (figure 1). Standard gemological testing gave a spot RI of 1.54 and an SG of approximately 2.66, and we observed inclusions of fuchsite mica, properties all consistent with aventurine quartz. More advanced methods, namely FTIR and Raman spectroscopy, were also applied. The FTIR spectrum (figure 2) revealed the polymer treatment of the piece. The long-wave UV light reaction was a very strong blue (figure 3), which appeared to confirm the treatment. Natural aventurine normally has an inert to weak reaction to long-wave UV light; by contrast, polymers generally show a moderate to very strong blue reaction. The acid-damaged surface structure observed with a microscope also corresponded with the treatment procedures used on jadeite.

Figure 2. FTIR testing of the bangle revealed polymer impregnation at the 3000–3100 cm–1 absorption in the mid-infrared region.

Figure 3. Notably, the bangle had a very strong blue reaction to long-wave UV light. Photo courtesy of Lai Tai-An Gem Lab.
In our experience, polymer-impregnated aventurine quartz is rarely encountered in the jewelry market. Still, its resemblance to “ice jade” shows that buyers should be fully aware of the potential risk of misidentifying such material. Source: GIA @topic:11


Title: Emerald: The Superstar of Trapiche Gemstones Abstract: This close-up view looks down the crystal axis of a backlit 58.83 ct trapiche emerald from Peñas Blancas, Colombia. Courtesy of Jose Guillermo Ortiz, Colombian Emerald Co. Photo by Robert Weldon/GIA

Emerald’s verdant color is a symbol of nature’s rebirth in spring, so it is appropriately named as the birthstone for those born in May. Colombian emeralds, found deep within the Cordillera mountains of the Andes, are some of the finest emeralds in the world. They are as lush as the rainforest, mountains and valleys where they have been concealed for millennia and sought for centuries.
Colombian emeralds are renowned for their vibrant green color, which comes from the element chromium, and gives them their highly prized hues. When these emeralds form as a trapiche crystal – a distinct pattern resembling a wheel with six spokes – they set the standard as some of the finest and most spectacular crystals unearthed.

These trapiche emeralds are from the Penas Blancas mine, Colombia. The rough crystal is 58.83 ct and the large cabochon is 22.74 ct. Two carbonaceous shale rocks with quartz, pyrite, and the beginnings of emerald formation are shown in the background. Courtesy Jose Guillermo Ortiz. Photo by Robert Weldon/GIA
When emerald miners first discovered these patterned gems, they called them trapiche, the Spanish word for the multi-spoked cogwheels rotated by oxen tied to a yoke to grind cane sugar. They were first described in 1879 by French mineralogist Emile Bertrand at a meeting of the Société Géologique de France.
Trapiche emeralds are found in the black shale host rocks of just a few Colombian mines in the western belt of the Eastern Cordillera Basin. Their appearance consists of a central core, six arms and black shale dendrites – a crystalline, branching tree-like structure that forms between the arms and around the core. They are visible when the crystals are viewed perpendicular to the c-axis and are often cut as cabochons to accentuate the six partitions.

The carbonaceous material has been removed from the emerald trapiche rough to form a "star" pattern. Courtesy of Jeffery Bergman, Primagem. Photo by Robert Weldon/GIA
Trapiche emeralds form in the same hydrothermal conditions as other Colombian emeralds, but their texture results from a complex growth history characterized by variations of fluid pressure in the structural geology of the deposits. The crystal’s hexagonal symmetry determines the number and the development of growth sectors, giving rise to the six arms.
The arms of trapiche gems remain fixed when the gem material or light source is moved. Its six arms can intersect in the middle or radiate from a central hexagonal core. The central core of a trapiche can be open or closed and taper from small to large within a single crystal, depending on how it formed.
The six-spoke pattern in trapiche is not asterism, which refers to a gemstone phenomenon brought about by the way light interacts with oriented needle-like inclusions in the gem. The arms of asteriated gems appear to glide across the surface when the light source or gem material is moved, but the arms of trapiche gems stay in place. [Note: There are only a few known emeralds that exhibit actual asterism.]

View Gallery

The Many Other species of Trapiche Gems
Trapiche emeralds were first sent to GIA for analysis in the mid-1960s. Since then, the trapiche six-arm texture or pattern has been observed in a few other gemstones, most notably in sapphire and ruby.
Trapiche rubies from Mong Hsu, Myanmar were first documented by GIA in 1995 and have since been found in Guinea, Kashmir, Pakistan, Nepal, Sierra Leone and Tajikistan. Trapiche sapphires first appeared on the gem market in early 1996, when samples were offered in Basel by a Berlin gem dealer. Trapiche sapphires have been found primarily in Australian, Cambodia, China, France, Kenya, Madagascar, Nepal, Sri Lanka and Tanzania.
All trapiche gemstones are relatively rare and some even more so. Some examples of the more rare or unusual trapiche gemstones include:

Pezzottaite is a rare gem material and extremely rare in trapiche formation. This trapiche pezzottaite is 2.33 cts. Courtesy of John I. Koivula. Photo by Kevin Schumacher/GIA

Pezzottaite (named after mineralogist Dr. Federico Pezzotta) first appeared at the 2003 gem shows in Tucson. Since then it has become a rare, coveted gemstone by collectors worldwide. It is a member of the beryl group, along with emerald and red beryl. All three are prized when in trapiche formation.
Tourmaline is relatively abundant in Zambia, although only a small percentage of crystals exhibit the trapiche pattern.

These muscovite trapiches, or “cherry blossom stones,” formed through alteration of complex indialite-cordierite intergrowths. The sample on the left has an open center and the one on the right exhibits a closed center. Photo by Nathan Renfro/GIA

Trapiche muscovite comes from only one locality, the Japanese city of Kameoka in Kyoto Prefecture, where they are locally known as “cherry blossom stones” (sakura-ishi in Japanese.)

The unique spoke pattern and variety of trapiche gemstones offer a natural geometric shape for jewelry designers looking for unusual, rare, and one-of-a-kind gemstones. None, however, can match an emerald’s majestic beauty – the superstar of trapiche gemstones. Source: GIA @topic:1


Title: The Separation of Natural from Synthetic Emeralds by Infrared Spectroscopy Abstract: Infrared spectroscopy provides a means to distinguish natural from synthetic emeralds in the range 2000-5000 cm-1, as determined by a study of spectra obtained from 37 natural, 19 hydrothermal synthetic, and 38 flux synthetic emeralds from a variety of sources. The technique is nondestructive and, with Fourier transform instrumentation, extremely rapid in comparison to most laboratory methods. It is especially useful for identifying stones that contain no distinguishing inclusions. Source: GIA @topic:3


Title: Suggested Reading on Rubies and Their Inclusions Abstract: Anderson B.W. (1949) Reconstructed rubies. G&G, Vol. 6, No. 6, pp. 187–190.

Bowersox G.W., Foord E.E., Laurs B.M., Shigley J.E., Smith C.P. (2000) Ruby and sapphire from Jegdalek, Afghanistan. G&G, Vol. 36, No. 2, pp. 110–126, http://dx.doi.org/10.5741/GEMS.36.2.110

Chapin M., Pardieu V., Lucas A. (2015) Mozambique: A ruby discovery for the 21st century. G&G, Vol. 51, No. 1, pp. 44–54, http://dx.doi.org/10.5741/GEMS.51.1.44

Dirlam D.M., Misiorowski E.B., Tozer R., Stark K.B., Bassett A.M. (1992) Gem wealth of Tanzania. G&G, Vol. 28, No. 2, pp. 80–102, http://dx.doi.org/10.5741/GEMS.28.2.80

Emmett J., Scarratt K., McClure S.F., Moses T., Douthit T.R., Hughes R., Novak S., Shigley J.E., Wang W., Bordelon O., Kane R.E. (2003) Beryllium diffusion of ruby and sapphire. G&G, Vol. 39, No. 2, pp. 84–135, http://dx.doi.org/10.5741/GEMS.39.2.84

Gübelin E.J. (1940) Characteristics of Ceylon rubies. G&G, Vol. 3, No. 8, pp. 121–124.

——— (1940) Differences between Burma and Siam rubies. G&G, Vol. 3, No. 5, pp. 69–72.

——— (1944) Gemstone inclusions - Ruby. G&G, Vol. 4, No. 11, pp. 158–163.

——— (1949) Observations on reconstructed rubies. G&G, Vol. 6, No. pp. 186–187.

——— (1960) More light on beryls and rubies with synthetic overgrowth. G&G, Vol. 10, No. 4, pp. 105–113.

——— (1982) New synthetic rubies made by Professor P.O. Knischka. G&G, Vol. 18, No. 3, pp. 165–168, http://dx.doi.org/10.5741/GEMS.18.3.165

Gübelin E.J., Meyer H.O.A. (1981) Ruby in diamond. G&G, Vol. 17, No. 3, pp. 153–156, http://dx.doi.org/10.5741/GEMS.17.3.153

Hänni H.A., Schmetzer K. (1991) New rubies from the Morogoro area, Tanzania. G&G, Vol. 27, No. 3, pp. 156–167, http://dx.doi.org/10.5741/GEMS.27.3.156

Hänni H.A., Schmetzer K., Bernhardt H.J. (1994) Synthetic rubies by Douros: A new challenge for gemologists. G&G, Vol. 30, No. 2, pp. 72–86, http://dx.doi.org/10.5741/GEMS.30.2.72

Holmes R.J. (1947) The new Linde Stars man-made star rubies and star sapphires. G&G, Vol. 5, No. 11, pp. 452–456, 478–479.

Howell D.H. (1936) The ruby mines of Burma - Part 1 and 2. G&G, Vol. 2, Nos. 1/2, pp. 3–6, 31–34.

Huong L.T.T., Häger T., Hofmeister W., Hauzenberger C., Schwarz D., Long P.V., Wehrmeister U., Khoi N.N., Nhung N.T. (2012) Gemstones from Vietnam: An update. G&G, Vol. 48, No. 3, pp. 158–176, http://dx.doi.org/10.5741/GEMS.48.3.158

Kammerling R.C., Keller A.S., Scarratt K.V., Repetto S. (1994) Update on mining rubies and fancy sapphires in Northern Vietnam. G&G, Vol. 30, No. 2, pp. 109–114, http://dx.doi.org/10.5741/GEMS.30.2.109

Kane R.E. (1979) Synthetic rubies. G&G, Vol. 16, No. 7, pp. 206–207.

——— (1983) The Ramaura synthetic ruby. G&G, Vol. 19, No. 3, pp. 130–148, http://dx.doi.org/10.5741/GEMS.19.3.130

——— (1984) Natural rubies with glass-filled cavities. G&G, Vol. 20, No. 4, pp. 187–199, http://dx.doi.org/10.5741/GEMS.20.4.187

——— (1985) A preliminary report on the new Lechleitner synthetic ruby and synthetic blue sapphire. G&G, Vol. 21, No. 1, pp. 35–39, http://dx.doi.org/10.5741/GEMS.21.1.35

Kane R.E., Kammerling R.C. (1992) Status of ruby and sapphire mining in the Mogok Stone Tract. G&G, Vol. 28, No. 3, pp. 152–174, http://dx.doi.org/10.5741/GEMS.28.3.152

Kane R.E., McClure S.F., Kammerling R.C., Khoa N.D., Mora C., Repetto S., Khai N.D., Koivula J.I. (1991) Rubies and fancy sapphires from Vietnam. G&G, Vol. 27, No. 3, pp. 136–155, http://dx.doi.org/10.5741/GEMS.27.3.136

Keller P.C. (1982) The Chanthaburi-Trat gem field, Thailand. G&G, Vol. 18, No. 4, pp. 186–196, http://dx.doi.org/10.5741/GEMS.18.4.186

——— (1983) The rubies of Burma: A review of the Mogok Stone Tract. G&G, Vol. 19, No. 4, pp. 209–219, http://dx.doi.org/10.5741/GEMS.19.4.209

Kissin A.J. (1994) Ruby and sapphire from the Southern Ural Mountains, Russia. G&G, Vol. 30, No. 4, pp. 243–252, http://dx.doi.org/10.5741/GEMS.30.4.243

Koivula J.I., Johnson M.L. (1996) Rubies from Madagascar. G&G, Vol. 32, No. 2, pp. 133–135.

Koivula J.I., Kammerling R.C. (1988) Gem News: Ruby receives highest price at auction. G&G, Vol. 24, No. 4, pp. 252.

——— (1988) A gemological look at Kyocera’s new synthetic star ruby. G&G, Vol. 24, No. 4, pp. 237–240, http://dx.doi.org/10.5741/GEMS.24.4.237

Liddicoat R.T. (1969) Kashan flux grown rubies. G&G, Vol. 13, No. 1, pp. 30–34.
McClure S.F., Kammerling R.C., Fritsch E. (1993) Update on diffusion-treated corundum: Red and other colors. G&G, Vol. 29, No. 1, pp. 16–28, http://dx.doi.org/10.5741/GEMS.29.1.16

McClure S.F., Smith C.P., Wang W., Hall M. (2006) Identification and durability of lead glass-filled rubies. G&G, Vol. 42, No. 1, pp. 22–34, http://dx.doi.org/10.5741/GEMS.42.1.22

Meyer H.O.A., Gübelin E.J. (1981) Ruby in diamond. G&G, Vol. 17, No. 3, pp. 153–156, http://dx.doi.org/10.5741/GEMS.17.3.153

Muhlmeister S., Fritsch E., Shigley J.E., Devouard B., Laurs B.M. (1998) Separating natural and synthetic rubies on the basis of trace-element chemistry. G&G, Vol. 34, No. 2, pp. 80–101, http://dx.doi.org/10.5741/GEMS.34.2.80

Nassau K. (1981) Heat treating ruby and sapphire: Technical aspects. G&G, Vol. 17, No. 3, pp. 121–131, http://dx.doi.org/10.5741/GEMS.17.3.121

Peretti A., Schmetzer K., Bernhardt H.-J., Mouawad F. (1995) Rubies from Mong Hsu. G&G, Vol. 31, No. 1, pp. 2–26, http://dx.doi.org/10.5741/GEMS.31.1.2

Pham V.L., Pardieu V., Giuliani G. (2013) Update on gemstone mining in Luc Yen, Vietnam. G&G, Vol. 49, No. 4, pp. 233–245, http://dx.doi.org/10.5741/GEMS.49.4.233

Schmetzer K., Peretti A. (1999) Some diagnostic features of Russian hydrothermal synthetic rubies and sapphires. G&G, Vol. 35, No. 1, pp. 17–28, http://dx.doi.org/10.5741/GEMS.35.1.17

Schmetzer K., Schupp F.J. (1994) Flux-induced fingerprint patterns in synthetic ruby: An update. G&G, Vol. 30, No. 1, pp. 33–38, http://dx.doi.org/10.5741/GEMS.30.1.33

Schmetzer K., Hänni H.A., Jegge E.P., Schupp F.J. (1992) Dyed natural corundum as a ruby imitation. G&G, Vol. 28, No. 2, pp. 112–115, http://dx.doi.org/10.5741/GEMS.28.2.112

Schmetzer K., Hänni H.A., Schwarz D. (1996) Trapiche rubies. G&G, Vol. 32, No. 4, pp. 242–250, http://dx.doi.org/10.5741/GEMS.32.4.242

Schmetzer K., Steinbach M.P., Gilg H.A., Blake A.R. (2015) Dual-color double stars in ruby, sapphire and quartz: Cause and historical account. G&G, Vol. 51, No. 2, pp. 112–143, http://dx.doi.org/10.5741/GEMS.51.2.112

Schwarz D., Pardieu V., Saul J.M., Schmetzer K., Laurs B.M., Giuliani G., Klemm L., Malsy A.K., Erel E., Hauzenberger C., Du Toit G., Fallick A.E., Ohnenstetter D. (2008) Rubies and sapphires from Winza, central Tanzania. G&G, Vol. 44, No. 4, pp. 322–347, http://dx.doi.org/10.5741/GEMS.44.4.322

Shor R., Weldon R. (2009) Ruby and sapphire production and distribution: A quarter century of change. G&G, Vol. 45, No. 4, pp. 236–259, http://dx.doi.org/10.5741/GEMS.45.4.236

Smith C.P. (1996) Introduction to analyzing internal growth structures: Identification of the negative d plane in natural ruby. G&G, Vol. 32, No. 3, pp. 170–184, http://dx.doi.org/10.5741/GEMS.32.3.170

——— (2002) Diffusion ruby proves to be synthetic ruby overgrowth on natural corundum. G&G, Vol. 38, No. 3, pp. 240–248, http://dx.doi.org/10.5741/GEMS.38.3.240

Smith C.P., Gübelin E.J., Bassett A.M., Manandhar M.N. (1997) Rubies and fancy-color sapphires from Nepal. G&G, Vol. 33, No. 1, pp. 24–41, http://dx.doi.org/10.5741/GEMS.33.1.24

Sorokina E.S., Litvinenko A.K., Hofmeister W., Häger T., Jacob D.E., Nasriddinov Z.Z. (2015) Rubies and sapphires from Snezhnoe, Tajikistan. G&G, Vol. 51, No. 2, pp. 160–175, http://dx.doi.org/10.5741/GEMS.51.2.160

Spaulding D.L. (1956) The ruby mines of Mogok, Burma. G&G, Vol. 8, No. 11, pp. 335–342.
Vertriest W., Pardieu V. (2016) Update on gemstone mining in northern Mozambique. G&G, Vol. 52, No. 4, pp. 404–409, http://dx.doi.org/10.5741/GEMS.52.4.404 Source: GIA @topic:1


Title: Winter 2008 G&G Book Reviews Abstract: “Photoatlas of Inclusions in Gemstones, Volume 3”
By E. J. Gübelin and J. I. Koivula, 672 pp., illus., publ. by Opinio Publishers, Basel, Switzerland [www.publications.microworldofgems.com], 2008. US$299.00

“Bulgari”
By Amanda Triossi and Daniela Mascetti, 2nd ed. (revised and updated by Amanda Triossi), 320 pp., illus., publ. by Abbeville Press, New York [www.abbeville.com], 2007. US$75.00

“Guidebook to the Pegmatites of Western Australia”
By Mark Ivan Jacobson, Mark Andrew Calderwood, and Benjamin Alexander Grguric, 356 pp., illus., publ. by Hesperian Press [www.hesperianpress.com], Victoria Park, Australia, 2007. US$85.00

“Crazy About Jewelry! The Expert Guide to Buying, Selling and Caring for Your Jewelry”
By Susan Eisen, 245 pp., illus., publ. by Full Circle International Publishing
[www.crazyaboutjewelry.net], El Paso, TX, 2007. US$16.95

To view the full section, download the PDF above. Source: GIA @topic:10


Title: Unique Orange Sapphire with Golden Sheen Effect Reportedly from Kenya Abstract: Figure 1. This 4.34 ct transparent oval-cut orange sapphire displayed an attractive golden sheen effect. Photo by Tasnara Sripoonjan.

Golden sheen sapphires from Kenya have been reported in this journal and elsewhere (e.g., T.N. Bui et al., “From exsolution to ‘gold sheen’: A new variety of corundum,” Journal of Gemmology, Vol. 34, No. 8, 2015, pp. 678–691; N. Narudeesombat et al., “Golden sheen and non-sheen sapphires from Kenya,” The Gem and Jewelry Institute of Thailand, July-August 2016, pp. 282–288). Those sapphires, however, were the cabochon-quality blue-green-yellow stones that exhibited a shimmering golden effect caused by the light reflection from hematite platelets and needle-like inclusions. No faceted transparent stones have been mentioned in the previous literature. Recently the Gem and Jewelry Institute of Thailand’s Gem Testing Laboratory in Bangkok encountered a faceted orange sapphire with an attractive golden sheen effect that was reportedly from Kenya.
The sample was a transparent, 4.34 ct faceted mixed-cut stone of orange hue with attractive golden sheen effect almost throughout the crown facets (figure 1). Standard gemological testing revealed a refractive index (RI) of 1.765 to 1.775, a birefringence of 0.01 with a uniaxial negative optic sign, and a hydrostatic specific gravity (SG) of 3.98. The stone exhibited brownish orange and greenish yellow pleochroism and was inert to both long- and short-wave UV radiation. Microscopic observation revealed abundant metallic hematite platelets and rutile needles (figure 2, left), confirmed by Raman spectroscopy, that were situated along the basal pinacoid face. A cluster of zircon crystals, as suggested by its crystal morphology, could also be found in the specimen (figure 2, right).

Figure 2. Internal features of the orange golden sheen sapphire: abundant metallic hematite platelets and rutile needles (left) and a cluster of zircon crystals (right). Photomicrographs by Saengthip Saengbuangamlam; field of view 3.00 mm.
In previous studies, the golden sheen sapphires from Kenya were translucent to opaque, with yellow and blue bodycolor (Bui et al., 2015; Narudeesombat et al., 2016). They contained abundant internal features, such as exsolved intergrowth Fe-Ti oxide phases of hematite platelets and short ilmenite needles that gave the sheen effect, as well as inclusions of goethite, boehmite, and diaspore needles. They also had large surface-reaching cracks. The stone in this investigation is orange, transparent, and without surface-reaching cracks, though it also possesses a significant number of hematite platelets that are in part responsible for its golden sheen effect.

Figure 3. UV-Vis spectra of the orange golden sheen sapphire showing Fe3+ - and Cr3+-related absorption peaks and bands.
The polarized ultraviolet-visible (UV-Vis) spectra of the specimen displayed predominantly Fe3+-related absorption bands at 378, 388, and 450 nm that are responsible for its yellow hue (e.g., J. Ferguson and P.E. Fielding, “The origins of the colours of natural yellow, blue and green sapphires,” Australian Journal of Chemistry, Vol. 25, No. 7, 1972, pp. 1371–1385), whereas the absorption band at around 557 nm (also at ~410 nm) is caused by a Cr3+ transition contributing to the reddish hue (figure 3). As such, the stone coloration appears orange. R-line luminescence of Cr3+ near 693 nm also appears in the spectra. When compared to the more common non-sheen counterparts, the UV-Vis spectra yield only Fe3+- and Fe-Ti-related absorptions (Narudeesombat et al., 2016).

The energy-dispersive X-ray fluorescence (EDXRF) results of the orange sapphire showed very high content of Fe2O3 (1.94 wt.%) with moderate content of Cr2O3 (0.05 wt.%) and TiO2 (0.04 wt.%). Ga2O3 and V2O5 were equal at about 0.01 wt.%. This result (particularly the iron content) is somewhat similar to those of the common golden sheen and non-sheen stones from Kenya in the previous work (table 1), which also suggests a similar magmatic source. Nonetheless, the Cr2O3 content in this orange sapphire is particularly distinctive, since such an oxide is almost undetectable in most golden sheen sapphires.
While Kenya is known to supply large amounts of golden sheen sapphires, some rare orange sapphires with sheen effect such as this one are also being supplied to the market. Sheen effect makes the stone distinctive compared to common orange sapphire from other sources, for example, from Songea in Tanzania (cf., originating from a metamorphic source and having somewhat lower iron content). However, the owner informed us that this specimen might eventually be subjected to heat treatment at a relatively low temperature to remove some silk-like inclusions and make it more transparent. Nevertheless, careful examination yielded no indication that this stone was heated. Its unique characteristics—heavily included hematite platelets and rutile needles that give rise to the golden sheen effect plus its high iron content—suggest a Kenyan origin. Source: GIA @topic:3


Title: G&G Features in a Flash: Texas Topaz Abstract: The 13.8 carat round topaz has a Lone Star cut, faceted to display the five-point star of the Texas state flag. Courtesy of Cub Root (Form to Feeling, Austin, Texas). Photos: Blanca Espinoza.

What is Topaz?
Topaz is a gem valued for its clarity and hardness (Mohs 8) as well as its wide variety of colors, including colorless, yellow, blue, brown, pink, orange, and red.

In its purest state, topaz is colorless, but defects and impurities in the crystal can create color centers. Chromium can cause topaz to turn pink to violet. A combination of oxygen and radiation can turn pink to violet topaz orange, making it the valued Imperial topaz. Other oxygen-related defects can produce brown or blue topaz.

Artificial irradiation and heat treatments can also turn colorless topaz blue. This treatment was first used in 1957 and became widely used during the late 1970s. The low cost and popularity of blue topaz made it the most commonly irradiated gemstone on the market. This treatment is now so widespread that any blue topaz on the market is assumed to have been irradiated unless stated otherwise. Naturally blue topaz is rare and highly desirable.

GIA researchers studied these rough topaz from Mason County, Texas. The large blue specimen weighs 188 carats. Courtesy of Diane Eames. Photo: Emily Lane/GIA.
"Texas Topaz"

Mason County, Texas, is well known in the gem world for producing beautiful topaz. While most topazes found here are colorless, light blue, or brown, some are a natural saturated blue color. These saturated blue stones are known as “Texas topaz” in the trade and are highly sought after for their provenance and natural blue color.

Topaz was first found in Mason County in the late 1800s, long before topaz treatments were developed. For a while, it was considered a local gem. Most gems found were between one to ten carats in size, with the largest ever found weighing 6,800 carats. During World War II, many scientists moved to the Southwest for the nuclear weapons program and began mining recreationally on weekends. This launched several gem and mineral groups in the area and an increased interest in topaz. Topaz from Mason County became popular at faceting competitions and Texas gem and mineral shows. In 1969, “Texas topaz”—blue topaz from Mason County—was recognized as the official state stone.

Texas topaz was still largely a hobbyist’s stone, however, until the early 2000s when Diane Eames and Brad Hodges, owners of a jewelry store in the town of Mason, built a successful jewelry business that focused on locally mined and cut Texas topaz. They launched an advertising campaign that helped this stone reach a national audience and elevated its prestige.

	This 925 carat crystal was found in 1904 and was on the Texas governor’s desk when the legislature adopted Texas topaz as the state gem in 1969. This crystal now resides in the Hamman Gem and Mineral Gallery in the Department of Earth and Planetary Sciences at the University of Texas at Austin. Photo: Blanca Espinoza.
GIA Research on Texas Topaz
Because of its origin, Texas topaz has a much higher regional value than similarly colored topaz from other localities. The two greatest determiners of Texas topaz’s value are the saturation of its blue color and its cut quality. A popular cut style for this gemstone is the Lone Star cut, which produces a five-pointed star shape in the middle of the gem and gives the gem a deep pavilion to intensify its color.

The Lone Star cut developed specifically for Texas topaz. (A) Photo: Blanca Espinoza. Courtesy: Form to Feeling. (C) Photo: Bradley Hodges.
Given the unique nature of Texas topaz, GIA researchers embarked on a gemological and analytical study of topaz from Texas, examining its trace element composition to find ways to distinguish Texas topaz from topaz from other locales. GIA researchers studied 83 rough topaz specimens from Mason County, Texas, and 379 topaz specimens from other locations in the U.S. and from other countries, including Australia, Brazil, Colombia, Germany, Guyana, Japan, Zimbabwe, and more. The topazes studied had a range of colors, including colorless, brown, and blue.

A 188 carat waterworn alluvial Texas topaz. Photo: Emily Lane/GIA. Courtesy: Diane Eames.
GIA researchers discovered that the most significant trace elements in topaz from Texas were scandium, titanium, germanium, and chromium. GIA researchers used machine learning to predict which stones were most likely from Texas based on their trace element profiles. Machine learning incorrectly classified 7% of the topaz from other countries as being from Texas. Samples from Namibia, Nigeria, Australia, and from California and Indiana in the United States were the most common false positives.

Samples from Brazil, Guyana, Colombia, Zimbabwe, and Mexico had the lowest false positives. GIA scientists were able to study more stones from Brazil, Guyana, Colombia, Zimbabwe, and Mexico than from Namibia, Nigeria, Australia, California, and Indiana. They concluded that false positives were more likely to occur for stones that were not as well represented in their sample (there were fewer of them compared to stones form other locales). It is also possible that topazes from Texas, other U.S. locales, and Australia formed in similar geological conditions, resulting in similar trace element compositions and higher false positives.
Conclusion
Currently, GIA researchers can provide a fairly reliable estimate of the likelihood that a stone originates from Texas. More research needs to be done on larger sample sizes of topazes for country of origin to be determined, however. Nonetheless, these findings suggest that the trace element compositions of most Texas topaz are distinct enough to distinguish them from topaz found in other parts of the world. This implies that determining the geographical origin may become possible in the future, with additional factors such as fluorescence color and inclusions contributing to increased certainty. Source: GIA @topic:1


Title: De Beers’ Sight: Still Too Rich For Some Dealers Abstract: Photo courtesy of De Beers.

	De Beers’ new chairman, Mark Cutifani, was greeted by a July sight that had clients, once again, leaving a lot of goods on the table ‒ as much as 7 to 8%. Sightholders said the goods were too pricey for the current market, adding that their banks have become much stingier. For Indian sightholders, the depressed rupee makes De Beers’ rough that much more expensive.

	The size of the sight was similar to June’s allocation of $585 million, with no significant price changes.

	Sightholders’ refusal to purchase part of their allocations has become a recurring issue. Diamond manufacturers have been caught in a price/credit squeeze that is taking most of their profits. Rough prices have soared at a rate far exceeding polished in the past three years with some polished goods bringing less than the rough they came from. At the same time, banks in India, which finance a majority of diamond manufacturers, have cut their credit facilities to the trade by an estimated 15%.  Adding to their costs, the value of the rupee has plunged more than 10% against the U.S. dollar in recent months, making purchases of rough that much more costly.

	At the same time, retailers in the U.S. and Asia have refused to budge on prices, preferring to downtrade color or clarity rather than pay the additional cost for higher-quality goods.

	The new De Beers chairman, also chairman of De Beers’ majority owner Anglo American Corp., has to juggle the challenges of the diamond industry with shareholder pressure to raise revenues and production.

	AFRICA: Botswana’s first auction of rough diamonds in July realized nearly $20 million, with prices of some lots selling for more than 50% above their reserves.

	The pilot sale, open to a broader group than the De Beers sightholders, was operated by Okavango Diamond Sales, a government agency located in Diamond Technology Park.

	Approximately 123,000 carats of rough, in sightbox sizes – ranging from 5-10 carats down to 3 to 5 pointers ‒ and qualities, was auctioned. “Specials” larger than 10 carats, which De Beers sells separately, were not included.

	Some analysts claim the auction results showed that De Beers’ prices are far too low, noting that some lots greatly exceeded their pre-sale reserves. The auction prices, in real terms, were only about 5% higher than Botswana’s 2012 average price per carat. The overall average auction price of $162 per carat was 10.5% higher than Botswana’s average price per carat for its entire production last year ($145), about half of which could be accounted for by the 4% to 6% price increases seen thus far this year.

	COLORED STONES: Gemfields’ delayed and relocated auction sale of high quality emerald rough realized a strong $31.5 million.  The 583,448 carat sale brought $54 per carat, just over $11 higher price per carat than last year’s sale held in Singapore.

	The sale had been scheduled for mid-June in Singapore. But the Zambian government, which is Gemfields’ 25% partner in the Kagem emerald mine, issued a requirement last spring that all gemstones mined in the country be sold within its borders, forcing the postponement and move.

	Gemfields’ CEO Ian Harebottle had expressed concern that moving the sale to Lusaka, Zambia’s capital would keep many of the big international buyers away and make sales vulnerable to local speculators, but 37 companies attended the sale, nearly all of them international firms.

	Zambia, the third-biggest emerald producer, may be backing away from its no-outside- sales-policy, however, saying it may allow sales in other venues ‒ as long as some goods are sold locally. After the sale, Harebottle noted that Lusaka was a “key hub” in the world emerald trade. Source: GIA @topic:8


Title: Amethystine Chalcedony Abstract: A new amethystine chalcedony has been discovered in Arizona. The material, marketed under the trade name "Damsonite," is excellent for both jewelry and carvings. The authors describe the gemological properties of this new type of chalcedony, and report the effects of heat treatment on it. Although this purple material is apparently a new color type of chalcedony, it has the same gemological properties as the other better-known types. It corresponds to a microcrystalline form of amethyst which, when heat treated at approximately 500°C becomes yellowish orange, as does some single-crystal amethyst. Source: GIA @topic:1


Title: A Simple Procedure to Separate Natural from Synthetic Amethyst on the Basis of Twinning Abstract: Dr. Karl Schmetzer recently showed how near-flawless to flawless natural amethyst could be separated from synthetic amethyst on the basis of the presence of Brazil twinning in the natural stones. Whereas Dr. Schmetzer's procedure required a special apparatus, the authors have determined that a standard gemological polariscope is more than adequate to make the separation in most cases. Although some synthetic amethyst does show evidence of twinning, in the synthetic stones examined thus far it has taken a form that is distinctly different from the Brazil twinning seen in most natural amethysts. The presence of certain inclusions as well as the nature of the color zoning seen in natural versus synthetic amethysts is of primary use in making a separation. However, where there are no inclusions or color zoning, the presence of Brazil twinning in the natural amethyst will usually make the distinction. Source: GIA @topic:3


Title: Looking Ahead to 2014 Abstract: Welcome to the Winter 2013 Gems & Gemology. In this issue, we’re privileged to present a significant paper reviewing the current state of knowledge about diamond geology. The article’s lead author is Dr. Steven B. Shirey, a noted isotope geochemist from the Carnegie Institution of Washington and a leader in the field of inclusion-dating techniques as applied to diamond. Recent research in this area has helped date the oldest known diamonds back to 3.5 billion years—more than three-quarters the age of the earth. This article, which updates the landmark Spring 1991 G&G paper on the same topics by Melissa Kirkley et al., is co-authored by GIA’s Dr. Jim Shigley.

We hope this is the first of many articles chronicling the new frontiers of diamond research from Carnegie’s scientists. In the near future, we look to forge other active collaborations with institutions and researchers working in gem-related fields.

The Winter issue also includes excellent papers on blue sapphires from the Baw Mar area in Mogok, Myanmar; an update on gemstone mining in Luc Yen, Vietnam; and the characteristics of coated jadeite jade.

As always, we would be delighted to hear from our readers on any of the papers in this issue, or previous 2013 issues.

Now that we are on the cusp of G&Gs 80th anniversary in 2014, this is a fitting time to review some of the innovations we’ve brought to our readers during 2013. In April, we launched the Research & News section of the new GIA website and made every issue of G&G, from the current issue back to the journal’s launch in 1934, free to all users as PDF downloads at http://www.gia.edu/gems-gemology.

In the Fall issue, we introduced a new G&G article category: the field report. In upcoming issues, we aim to bring our readers more of these “direct from the mine” articles, particularly from GIA’s dedicated field gemologists, Vincent Pardieu and Andy Lucas.

With G&G now at the center of GIA’s Research & News portal, we have the opportunity to complement our articles with supporting media. In our Fall issue, we supplemented the Cheapside Hoard and Oregon sunstone papers with video interviews, image slideshows, and additional articles. This is a trend we intend to expand on in 2014. In the print version of this issue, in fact, you’ll notice a QR (quick response) code at the end of our lead article on diamond geology. This takes users with enabled smartphones and tablets directly to videos and related online content.

We also started integrating G&G into GIA’s gemology curriculum, beginning with the Diamonds & Diamond Grading course. Students can now directly access and download relevant articles via links from their eLearning course assignments. In 2014, we will extend this initiative to the remaining gemology courses.

May I take this opportunity to wish all our contributors, subscribers, reviewers, and online readers the very best for 2014.

Duncan Pay
Editor-in-Chief Source: GIA @topic:7


Title: Star Spinel with Four and Six Rays Abstract: Lotus Gemology receives submissions of star stones on a regular basis, so when we first saw the specimen shown here, it appeared to be one among many of our usual stones to test. Upon closer examination, however, we realized it was not a star sapphire, but something much more rarely seen: star spinel.
Upon first glance at the cabochon’s dome, the stone displays one six-rayed star (figure 1), similar to what we see in star corundum. But if we look on the sides of the stone, we can also see a four-rayed star (figure 2).

Figure 2. When viewed in a different position, the spinel also displays a four-rayed star. Photomicrograph by E. Billie Hughes; specimen courtesy of Global Spinel Gems.
>These stars are both created from numerous dense, short needle-like particles. Once we examined a small polished area on the cabochon’s base, we found that there are actually two distinct types of exsolution products in the stone. On the right side of figure 3, we can see the tiny, dense needles and particles that form both types of stars. In the center of the image we can see much larger, less densely dispersed platelets that resemble confetti.

Figure 3. In the center of the image we can see larger reflective platelet inclusions in the untreated star spinel. On the right-hand side, we see much finer dense needles that form both six-rayed and four-rayed asterism. Photomicrograph by E. Billie Hughes; specimen courtesy of Global Spinel Gems. Source: GIA @topic:3


Title: Garnet Quality Factors Abstract: Garnet comes in as wide a variety of sizes and shapes as it does colors.

                      Garnets are a group that includes a number of different minerals, so appearance can vary widely. The first thing a buyer of garnets needs to be aware of is the wide variety of garnet types.

At first, the sheer number of garnet varieties can seem bewildering. It helps to think of the different types of garnets in terms of color.

Color
Pyrope and almandine range in color from purple to orangy red. Spessartine is found in a variety of orange colors, while andradite comes in yellow and yellowish green. Grossular has perhaps the widest color range of any garnet species, from colorless through yellow to reddish orange and orangy red, to a strong, vibrant green.

	These vibrant spessartine garnets are from the US state of Virginia, another important historical source for collectors. - Gift of John Bradshaw

	This tsavorite garnet has an appealing green color and is a 68.82-carat gem. - Courtesy New Era Gems

	This 3.20-carat demantoid garnet’s vivid green hue is exceptionally beautiful. In fact, it’s close to the top color for this variety. The gem is mounted in a platinum ring with diamond accents. - Courtesy A Touch of Color
Gemologists and colored stone dealers further subdivide some garnet species into varieties depending on color. For example, demantoid is a brilliant green variety of andradite that’s highly prized by collectors. Both tsavorite and hessonite are varieties of grossular. Tsavorites are green, while hessonite ranges from orange and orangy red to brownish red. Rhodolite is a purplish red variety.

	Rhodolite is the purplish variety of pyrope-almandine garnet. It can be spectacular, like this 8.72-carat gem.
Clarity
Typical garnet clarity depends on garnet type. For example, the red garnets almandine, pyrope, and rhodolite typically do not have eye-visible inclusions. Some of the orange garnets, like spessartine and hessonite, often have eye-visible inclusions.

	Hessonite garnet often has a turbulent inner appearance called the roiled affect. - © GIA & Tino Hammid, courtesy Gordon Bleck

	Demantoid might have eye-visible inclusions called horsetails that can raise its value.
Grossular is typically translucent, making it popular for cabochons, beads, and carvings.

Cut
Many garnets are cut into standard shapes and standard sizes to allow easy setting into jewelry. This is especially true of many red garnets. Expensive garnets like fine-quality tsavorite are cut into shapes and cutting styles that allow more of the weight to be retained from the rough.

	Garnets come in a variety of shapes and cutting styles.
Demantoid is often cut to exact proportions that allow the best possible display of its fire. Garnets are also popular for designer cuts and carvings. Red garnets are classic materials for cutting into cabochons and beads. They are commonly found to have high clarity and to be very transparent.

Carat Weight
Garnets can be found in all sizes and weights. Some garnets, like demantoid and tsavorite, are more commonly found in small sizes, so their value goes up significantly with size. Other garnets, like almandine, are far more common in larger sizes so there’s no dramatic rise in value as size increases. Source: GIA @topic:2