Title: Robert M. Shipley Sr. (1887–1978) Abstract: During the depths of the Depression, a middle-aged man with little more than ambition and charisma revolutionized the gem and jewelry industry. Robert M. Shipley established the Gemological Institute of America in 1931 as an education and research facility dedicated to the study of gems. From humble beginnings in his Los Angeles apartment, GIA would go on to become a global leader in gemology.

Shipley began his career as a retail jeweler in Wichita, Kansas. Although he cultivated the image of a gem expert, several embarrassing episodes revealed his lack of training. Divorce and the failure of his business during the mid-1920s sent him in search of a new life in Paris studying art. There he met his second wife, Beatrice, who introduced him to the right people and got him started as a museum lecturer. At the same time he discovered his love of teaching, Shipley enrolled in gemological correspondence courses offered by Great Britain’s National Association of Goldsmiths.

Inspired by the NAG courses and painfully aware of how little most retail jewelers knew about gems, Shipley returned to the United States with a vision: professionalizing the jewelry trade through education. GIA was the first organization of its kind in the United States. While traveling across the country to promote GIA courses, Shipley also established the Institute’s laboratory and instrument services.

In 1934, Shipley founded the American Gem Society as a professional guild of knowledgeable jewelers. That same year he established Gems & Gemology, GIA’s journal of gemological research. Shipley retired in 1952, but his far-reaching vision would influence future generations of gem and jewelry tradespeople. Source: GIA @topic:10


Title: Yellow Fluid Inclusions in Transparent Sodalite Abstract: Figure 1. This 7.17 ct colorless sodalite was remarkably transparent and contained interesting fluid inclusions. Photo by Sean-Andrew Z. Pyle.

The authors recently examined a 7.17 ct transparent, near-colorless sodalite submitted for identification service (figure 1). Sodalite is typically encountered as a semitransparent to opaque, violetish blue stone with white calcite veining resembling lapis lazuli.
Hackmanite is the sulfur-bearing variety of sodalite exhibiting tenebrescence (D. Kondo and D. Beaton, “Hackmanite/sodalite from Myanmar and Afghanistan,” Spring 2009 G&G, pp. 38–43). Tenebrescent minerals reversibly change color when exposed to UV light—from light purple to saturated purple, in the case of hackmanite. While this stone showed the strong orange fluorescence reportedly found in hackmanite, no change in color was observed. This was perhaps due to the short exposure time during testing.

Figure 2. These greenish yellow fluid inclusions were identified as hydrogen sulfide in solution. The gas bubble was matched to hydrogen sulfide gas. Photomicrograph by Tyler E. Smith: field of view 1.99 mm.
Microscopic observation revealed greenish yellow two-phase fluid inclusions reminiscent of petroleum in quartz (figure 2). Unlike petroleum in quartz, the fluid inclusions were inert to long-wave UV light. Raman spectra of the gas bubble and surrounding liquid were matched to gaseous hydrogen sulfide and hydrogen sulfide in solution, respectively. Methane-related peaks were also present in the liquid phase. These sulfur-rich fluid inclusions provided interesting geological evidence of the stone’s formation, making this rare sodalite even more exceptional. Source: GIA @topic:2


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

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

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

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

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

Figure 4. Under fiber-optic light, the material showed an eye-like pattern, with a pink and transparent center and blue and translucent sides. Also notice the hexagonal boundary made from the gas bubbles.  Photomicrograph by Pragati Verma; field of view 22.94 mm. Source: GIA @topic:3


Title: A Rare Ruby from Montana Abstract: Figure 1. Inclusions in the 1.70 ct ruby from Montana. Left: Close-up of a glassy melt inclusion with an associated thin film showing geometric patterns; field of view 1.76 mm. Right: A melt inclusion with an iridescent thin film, partial hexagonal zone of particles, and short needles; field of view 3.81 mm. Photomicrographs by Claire Malaquias.
The Carlsbad laboratory recently received a 1.70 ct purplish red octagonal modified brilliant-cut ruby measuring 6.28 × 6.25 × 4.56 mm for an identification and origin report. Standard gemological testing gave a chromium spectrum indicating ruby and a hydrostatic specific gravity (SG) of 4.00. The stone displayed a weak red fluorescence in long-wave UV and no fluorescence under short-wave UV.
Microscopic examination showed an interesting combination of inclusions (figure 1). There were several glassy melt inclusions and small crystals with associated reflective thin films. The thin films often displayed hexagonal geometric patterns conforming to the crystallographic orientation of the host ruby. These resembled the patterns commonly seen in rubies from Thailand and Cambodia and have also been documented in Montana corundum (Fall 2015 Micro-World, pp. 329–330). A partial hexagonal zone of particles and more loosely spaced unaltered exsolved rutile needles was also present, a feature that would be very unusual in Thai/Cambodian rubies. A large intact colorless crystal as well as smaller white crystals were located deep within the stone, so we were unable to conclusively identify them with Raman spectroscopy. This inclusion scene is consistent with unheated corundum from Montana.

Figure 2. The 1.70 ct Montana ruby alongside rough pink to purple corundum samples from the GIA reference collection. These reference samples, collected from Montana’s Eldorado Bar along the Missouri River and Wildcat Gulch, part of the Rock Creek deposit, were used to help determine the country of origin. Photo by Robison McMurtry.
Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) was used to determine the stone’s trace-element chemistry, and the results were compared to corundum samples from GIA’s colored stone reference collection. Trace element measurements indicated ranges of 15.1–17.2 ppma Mg, 14.7–16.9 ppma Ti, 3.67–3.87 ppma V, 359–406 ppma Cr, 1500–1580 ppma Fe, and 14.6–14.7 ppma Ga. The chemistry matched well with reference stones GIA has collected from Montana’s secondary deposits (figure 2) but not our Thai/Cambodian ruby reference samples. In particular, Thai/Cambodian rubies tend to have higher Mg (often above 100 ppma), while this stone had much lower Mg levels.
Montana’s secondary deposits produce sapphires in a wide range of mostly pastel colors. Pink corundum tends to be rarer than blue or green, and those that possess the depth of color to be called ruby are quite rare, particularly without any treatments. The color, combined with the large size, makes the 1.70 ct ruby from Montana an exceptional specimen—this is only the second such report issued by the lab to date. With a combination of microscopic observation, advanced testing methods, and GIA’s reference collection, we were able to confirm the country of origin. Source: GIA @topic:3


Title: Low-Fe, High-V Color-Change Burmese Sapphire Abstract: Figure 1. This 5.68 ct cushion mixed-cut sapphire showed a strong color change from grayish violet in fluorescent light to purple-pink in incandescent light. Photo by Robison McMurtry.
A color-change sapphire was recently submitted to the GIA lab in Carlsbad for an origin determination report. The 5.68 ct transparent cushion mixed cut displayed a strong color change from grayish violet in fluorescent light to purple-pink in incandescent light (figure 1). Color-change sapphires generally range from blue to violet in daylight-equivalent (fluorescent) light and from purplish pink to pinkish purple in incandescent light. Stones displaying a strong color-change phenomenon are highly desirable.

Figure 2. A: Exsolved rutile as reflective platelets, arrowheads, particles, and needles in sapphire; field of view 6.42 mm. B: Loose white particle clouds arranged in a geometric pattern and in stacked planes; field of view 3.80 mm. C: Twinning lamellae are commonly observed in Burmese sapphires; field of view 4.79 mm. D: Boehmite needles or tubules often occur with polysynthetic twinning; field of view 4.79 mm. E: Reflective fingerprints with iridescence in sapphire; field of view 1.37 mm. Photomicrographs by Jonathan Muyal.
Standard gemological testing proved that this stone was corundum with a refractive index (RI) of 1.760 to 1.768. Its weak ruby spectrum displayed absorption lines in the red area between 660 and 695 nm, a broad absorption in the green-yellow area between 500 and 600 nm, and two fine lines in the blue area between 460 and 480 nm. It fluoresced a strong patchy orange color under long-wave UV and a weaker orange under short-wave UV. Microscopic examination revealed exsolved rutile as reflective platelets, arrowheads, particles, and needles (figure 2A); loose white particle clouds arranged in geometric and stacked patterns (figure 2B); a series of twinning lamellae (figure 2C); boehmite needles or tubules (figure 2D); and reflective fingerprints with iridescence (figure 2E). No evidence of heat treatment was observed. The stone showed diffused pinkish purple zoning in immersion. This inclusion scene is common in but not limited to sapphires from Sri Lanka, Madagascar, and Myanmar (formerly Burma).
To help with the country of origin determination, we collected laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) chemistry. The results showed very low concentrations of iron, 11–13 ppma, and an unusually high vanadium at 300 ppma.
Several years ago a parcel of color-change sapphires was documented at GIA’s laboratory in Bangkok. That material, which had the same unusual chemistry of low Fe and high V, was from Myanmar. The chemistry profile of our client-submitted stone was consistent with that of the research stones previously documented from Myanmar.
This is the first time the Carlsbad lab has encountered a color-change sapphire with such a unique chemistry profile. LA-ICP-MS again proved to be a useful tool for gemstone origin determination, especially when the inclusion scenes of different localities overlapped. Source: GIA @topic:3


Title: Seek the World’s Most Vivid Blue Spinel with GIA Field Gemologists Abstract: Hunting for Spinels in Vietnam

	Join GIA’s field gemologists as they venture into Vietnam’s limestone mountains in search of the world’s most vivid blue spinel.

	In this new video from GIA’s field gemology department, you will accompany field gemologist Vincent Pardieu to Vietnam’s striking limestone mountains in search of sky-blue spinel.

	Although miners recover blue spinel in Sri Lanka, Tanzania, Myanmar, and Pakistan, Vietnam’s Luc Yen district is a leading source of the most vividly blue gems. The best of them have the same luminous quality as Paraíba tourmaline. “The blue spinel you have in Vietnam has really no equivalent,” explains Pardieu. “The top-quality blue spinel from Vietnam is really the top-quality blue spinel in the world, in my opinion.”

	Luc Yen district is located in Yen Bai province, in Vietnam’s scenic north. It’s a vivid patchwork of steep-sided, jungle-covered karsts separated by narrow valleys filled with paddy fields and villages. Luc Yen’s capital, Yen The (confusingly also known as Luc Yen), is about a six-hour drive, 250 km (155 miles) from Hanoi. All of the district’s blue spinel mining sites are within 20 km (12 miles) of the town.

	The GIA team starts off in Luc Yen’s bustling gemstone market. Before the 1990s discovery of Vietnamese ruby, Luc Yen was little known—a small agricultural backwater. The town grew rapidly after gems were discovered in the surrounding mountains and streams. Luc Yen’s first gem market opened in 1987, and today this once impoverished town is northern Vietnam’s busiest gem-trading center.

	At the market, gems from the area’s mountains and fields—rough spinel octahedra, faceted spinels, and cabochons—lie in rows on dealers’ little wooden tables. “Visiting the market here is quite an experience for anybody,” says gemologist Manny Diaz. Beautiful cobalt-blue spinels are present at many of the tables. “Material like this is really incredibly rare on the surface of the earth,” says Pardieu. He explains that visiting the local gem market is an excellent way to assess the availability of different materials. It also gives gemologists a way to assess current gem production in the local mining areas.

	It takes several hours to reach the blue spinel mines. The GIA team travels by motorcycle from the town to the countryside. Once there, they must make the trek up into a forbidding karst landscape to reach the mines. Luc Yen’s rugged limestone mountains formed when rainfall dissolved the limestone and created underground drainage systems, sinkholes, and caves. These features make it challenging to reach the mines, where ruby, sapphire, and spinel are recovered from primary and secondary deposits using artisanal methods. “If you want to go to see the primary mines that are producing this sky blue spinel, there is no other way,” remarks Pardieu. “You have to face the karst and go up in the mountain.”

	This means hours of steep ascent, navigating the sharp ridges and deep crevices that make up the face of the mountain. “There is a crevice about 4 to 5 meters deep, full of wood and sharp marble pinnacles,” observes Pardieu, “so you don’t want to fall in there!”

	“For the past ten minutes, we are climbing the Cung Troi cliff, which is the main spinel mining area here,” explains Pardieu. “Cung Troi is a very special place, as this is the place that produced most of the spinel crystals in matrix for the past 20 years.” Cung Troi—which means “Sky Gate”—is a source of pink-to-purple spinel, which occurs in marble along with minerals like pargasite. The spinels range in size from just a few millimeters to over five centimeters, and are of octahedral habit. Crystals in matrix are often carved into decorative shapes, which are highly valued due to the strong domestic market for items related to phong thuy—the Vietnamese version of feng shui.

	As the team nears the Cung Troi spinel mine, they clamber up steep slopes strewn with angular blocks and tailings of white marble. Standing in front of a marble cliff, gemologist Manny Diaz examines one half of a drill hole in a split rock face. “They’ll drill and they’ll pack that hole with an explosive…Once it falls, they’ll come down, out to the blast site and they’ll start picking up all the rubble,” he says. Miners attack the rubble with sledgehammers to look for spinel crystals, which stand out like glowing embers against the snowy white marble.

	When the team joins the miners in their hut for a meal, Pardieu explains Cung Troi’s geology: “It seems that you have three parallel veins…one with pink spinel, one with blue spinel, and one with ruby,” he says.

	Later, they watch as some miners struggle to move a huge marble block down a steep slope of angular, boulder-size tailings. “We just witnessed the team of miners that we spent the day with on the cliff, taking down a huge piece of marble that they collected from the top,” Pardieu observes. “Inside, we can see there is some pargasite, there is also some spinel. They’ll probably sell it to a carver and the carver will slowly take out the marble in order to reveal the spinel and the pargasite, which are hidden inside.” The heavy boulder tugs the miners downhill. They laugh, but they’re only barely in control.

	Next, the team reaches the Bai Son blue spinel mine—the main objective of the expedition. The primary deposit at Bai Son is located on a 600-meter high (1,970 foot) marble mountain. Local miners—mostly farmers—extract the spinel from the marble using hand tools and jackhammers. “Here we are on the blue spinel vein,” remarks Pardieu. “This is a most famous spot for blue spinel of the sky-blue quality.” Although blue spinel is found in the white marble at Bai Son, the crystals are usually of low transparency. Gems weathered out of the marble are also found in crevasses at Bai Son, and in places where miners follow the caves underground.

	Pardieu sums up the rationale for this and all the other field expeditions he conducts for GIA: “I travel to gem-mining areas around the world and I collect samples. So we need to have a reference sample from this area in order to be able to identify the stones that were mined in the past, that are mined today, and will be mined in the future.”

	This GIA Field Expedition (FE65) took place in 2015. Besides Pardieu, the participants were video cameramen Didier Barriere-Doleac and Didier Gruel, and expedition members Manny Diaz, Philippe Labrot, Lucie Martinez, Lauriane Pinsault, and Wim Vertriest. Source: GIA @topic:1


Title: Translucent Ruby Filled with Zinc Glass Abstract: Figure 1. An 8.57 ct heart-shaped fracture-filled ruby treated with a zinc glass filling. Photo by Adriana Robinson.

Figure 2. A fracture with whitish filler (left) and trapped air pockets (right). Photomicrographs by Shiva Sohrabi; fields of view 1.58 mm (left) and 2.90 mm (right).
Recently the Carlsbad laboratory received an 8.57 ct translucent purplish red heart-shaped mixed-cut stone for identification service (figure 1). Standard gemological testing revealed a refractive index of 1.760–1.769, and a ruby spectrum was obtained with a handheld spectroscope. The stone showed a medium to strong red fluorescence to long-wave UV radiation and a very weak red fluorescence to short-wave UV radiation. During microscopic analysis, several fractures containing a whitish filler and air pockets were seen using fiber-optic lighting (figure 2). Using reflected light, fractures with a lower luster than the host corundum were also observed, which confirmed the presence of a filling material.
The stone did not show the blue flash effect typically observed in rubies filled with lead glass (S.F. McClure et al., “Identification and durability of lead glass–filled rubies,” Spring 2006 G&G, pp. 22–36). Although the filler improved the durability, it did not appear to improve the clarity.
Glass filling treatment has been used on heavily fractured rubies to increase their clarity and durability since the early 1980s, and cavity filling was noted and described as early as 1984. The original filler was silica glass, which was easily visible since its refractive index (~1.5) is significantly lower than corundum (R.E. Kane, “Natural rubies with glass-filled cavities,” Winter 1984 G&G, pp. 187–199). In early 2004, gemologists discovered a new type of glass filler with high lead content and a much better clarity enhancement due to its higher reflective index (~1.70) (GAAJ Research Laboratory, “Lead-glass impregnated ruby,” March 15, 2004). Since then, lead glass fillers have become the most popular filler for rubies, although other glass types such as bismuth and cobalt have also been used (T. Leelawatanasuk et al., “Cobalt-doped glass-filled sapphire: An update,” Australian Gemmologist, Vol. 25, No. 1, 2013, pp. 14–20; Spring 2020 Lab Notes, p. 139).
In the heart-shaped ruby submitted to the laboratory, energy-dispersive X-ray fluorescence spectroscopy did not detect lead or bismuth but did show chromium, iron, and zinc. Additional chemical analysis was performed with laser ablation–inductively coupled plasma–mass spectrometry on two spots of one larger fracture with a substantial amount of filler in order to quantitatively measure the elements in the glass filler. The averages of the two analysis spots were 28750 ppmw silicon, 1091 ppmw zinc, and 108 ppmw lead.
Chemical results and gemological properties revealed that this glass filler was not the lead or bismuth glass the authors first suspected, but rather a silica-based glass doped with zinc. While this type of filler had visual properties similar to those of other glass fillers in corundum, it did not show a flash effect. This is the first time the authors have encountered a ruby filled with zinc glass. Source: GIA @topic:3


Title: A Gemological Pioneer: Dr. Edward J. Gübelin Abstract: During a career that spanned more than 65 years, the eminent Swiss gemologist Dr. Edward J. Gübelin (1913–2005) built a monumental legacy. He is perhaps best known for his pioneering work on gemstone inclusions. He established the first systematic classification of inclusions in natural gem minerals, and his research demonstrated the importance of these internal features in determining a gem’s identity as well as its country of origin. He wrote extensively on nearly all aspects of gemology, eloquently recording his observations in 13 major books and more than 250 articles. A widely traveled explorer, Dr. Gübelin also reported on some of the world’s most important gem localities. In addition, he was an innovator in gem-testing instruments, an influential educator, a major gem collector, and one of gemology’s most ardent and respected global ambassadors.

	DATA DEPOSITORY

Chronological Bibliography of Articles by Edward J. Gübelin
	Submitted by Robert E. Kane
	January 18, 2006 Source: GIA @topic:7


Title: Tree in Rock Crystal Quartz Abstract: Figure 1. This 80.60 ct rock crystal quartz cabochon contained an interesting tree-like metal sulfide inclusion. Photo by Robert Weldon.
The unusual quartz cabochon shown in figure 1 displays visually appealing dendritic inclusions that resemble trees. This inclusion scene is an excellent example of pareidolia, the tendency to assign familiar shapes to abstract forms (see Winter 2007 Lab Notes, pp. 363–364). Combined with a unique illumination technique, the inclusions are reminiscent of trees with green grass and a blue sky (figure 2).

Figure 2. Epigenetic metal sulfides are trapped in a partially healed fracture of rock crystal quartz. Modified Rheinberg illumination provides artificial blue and green color contrast reminiscent of grass and a sky. Photomicrograph by Nathan Renfro; field of view 20.14 mm. Courtesy of Mike Bowers.
The dendritic “tree” patterns are metal sulfide inclusions, as evidenced by their brassy yellow metallic color and opaque nature. When viewed with diffused fiber-optic lighting, the metal sulfide inclusions show a crisp foil-like texture near a partially healed internal fracture. This is likely where the metal sulfides entered the quartz host. They were deposited as an epigenetic residue in the fracture near the base of the tree, which was later healed, leaving behind the metal sulfides and numerous minute fluid inclusions where the fracture once was.
Adding green and blue filters behind the stone, known as modified Rheinberg illumination (Fall 2015, pp. 328–229), helped complete the appearance of a micro-landscape contained in the rock crystal quartz. This lighting technique is characterized by using contrasting color filters to bring striking color contrast to scenes viewed with a microscope (N.D. Renfro, “Digital photomicrography for gemologists,” Summer 2015 G&G, pp. 144–159). This unique quartz gem can be appreciated for the beautiful inclusion scene it contains. Source: GIA @topic:3


Title: Bent Rutile in Rock Crystal Quartz Abstract: Figure 1. Brownish red “bent” rutile with additional orangy needles displaying sagenitic twinning. Photomicrograph by Nathan Renfro; field of view 11.28 mm. Courtesy of Mike Bowers.

The authors recently examined a polished quartz disk with an unusual rutile (TiO2) inclusion (figure 1). Although rutile in quartz is reasonably common and has been well documented, this “bent” rutile was a fun oddity as it also contained small orangy sagenitic twinned rutile needles extending from the primary bend in the rutile needle. Rutile is most often seen as fine, straight needles (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Vol. 2, 2005, Opinio-Verlag Publishers, Basel, Switzerland, pp. 627 and 630). Rutile can play many roles as an inclusion and may contribute to phenomenal effects as well as to the bodycolor of an overall transparent colorless quartz (figure 2). While the exact cause of the bent nature of this rutile inclusion is unknown, the stone is a fascinating example of the unusual formation of inclusions in gems.

Figure 2. The polished transparent rock crystal quartz containing the bent rutile inclusion. Photo by Robert Weldon. Source: GIA @topic:3


Title: Demantoid from Baluchistan Province in Pakistan Abstract: Figure 1. These nine Pakistani demantoids showed dodecahedral form, magnetite inclusions, and asbestiform chrysotile masses on some crystal faces. The smallest stone (bottom left) is 5.2 mm wide, and the largest (top left) is 9.9 mm wide. Photo by Don Mengason.

              Demantoid garnet can be broadly divided into two petrogenetic groups, namely skarn-hosted and serpentinite-hosted demantoid. Those in the latter group represent the classic localities in the Russian Urals and at Val Malenco, Italy, in addition to sources such as Iran’s Kerman province and the Kaghan Valley area in the Hazara district of Pakistan. The serpentinite formations hosting these demantoids are the result of relatively low-grade hydrothermal/metamorphic alteration of ultramafic parent rocks.

Nine demantoids reportedly from a new deposit in the Khuzdar area in Pakistan’s Baluchistan province were recently examined in GIA’s Carlsbad lab (figure 1). The material was bought by one of these contributors (VP) from a gem merchant based in Peshawar, Pakistan.

The nine rough samples described here (1.74–3.73 ct) all exhibited well-developed crystal faces with typical dodecahedral form. Their color ranged from yellowish green to green, with yellow cores in a few samples. Each showed anomalous birefringence, often with a well-defined “octahedral” pattern (figure 2).

Figure 2. This demantoid is viewed through a polished window that is roughly parallel to the (110) crystal face. The sample was photographed with cross-polarized lighting and immersed in methylene iodide to highlight the anomalous birefringence. The sample measures 8.8 mm across. Photomicrograph by Aaron Palke.
Several of the garnets had fibrous (asbestiform) masses of chrysotile adhering to one or more crystal faces, confirming their origin in a serpentinite deposit. Windows were polished into several of these samples for microscopic examination of their internal features. Inclusions of chrysotile fibers (i.e., horsetail inclusions) are concentrated around the rim and radiate out toward the crystal faces (again, see figure 2). The cores of many samples were marked by a field of opaque, equant black inclusions initially presumed to be chromite (figure 3), a commonly observed inclusion in serpentinite-hosted demantoid.

Figure 3. These magnetite and fibrous chrysotile inclusions are typical of the demantoids from this study. Field of view is 2.0 mm. Photomicrograph by Nathan Renfro.
However, laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) analysis of one of these grains that had breached a polished surface showed Cr below the detection limit (2 ppm Cr). The analysis showed the almost exclusive presence of Fe, with minor Mg and Mn and trace amounts of other elements. This indicates that the opaque black inclusions in these demantoids are actually magnetite. This assignment was further confirmed by Raman analysis on another grain and the attraction of several of the garnets to a handheld magnet. LA-ICP-MS analysis of the host demantoid also revealed very low Cr concentrations from below the detection limit to approximately 10 ppm. This was in stark contrast to the typically Cr-rich serpentinite-hosted demantoid from other deposits. Along with the presence of magnetite instead of chromite, this probably indicated the absence of significant Cr in the ultramafic protolith. While the internal features were very similar to those in other serpentinite-hosted demantoid, the presence of magnetite instead of commonly reported chromite was a surprising feature of this newly described material. Source: GIA @topic:2


Title: Paraíba Tourmaline with Unusual Coating Abstract: Figure 1. The Paraíba tourmaline in this ring had an unusual submetallic surface coating. Photo by Masumi Saito.

	Paraíba tourmaline, named after the Brazilian state where it was discovered in the late 1980s, is a precious copper-bearing tourmaline variety (e.g., J.E. Shigley et al., “An update on ‘Paraíba’ tourmaline from Brazil,” Winter 2001 G&G, pp. 260–276). Treatments such as heating and clarity enhancement have been described (e.g., S.F. McClure et al., “Gemstone enhancement and its detection in the 2000s,” Fall 2010 G&G, pp. 218–240), but coating has never been reported.

	A Paraíba tourmaline ring with an unusual coating was recently submitted to GIA’s Tokyo laboratory for identification and origin service (figure 1). Standard gemological properties revealed a refractive index of 1.640–1.620, consistent with tourmaline. The stone showed medium to strong dichroism displaying greenish blue and light blue colors. Natural inclusions such as trichites and fingerprints were observed. We identified the stone as tourmaline using Raman spectroscopy. Energy-dispersive X-ray fluorescence (EDXRF) and UV-Vis spectroscopy were performed to confirm the presence of copper within the material, as well as the material’s cause of color.

	Viewed face-up with the unaided eye, the stone appeared normal. However, the coated surface looked different under reflected lighting and darkfield illumination (figure 2, left). A brassy, uneven submetallic luster was observed under reflected light, while whitish features in the submetallic luster area (figure 2, right) appeared under darkfield illumination. Coatings typically show signs of wear due to their low durability. This is often seen at the facet junctions. This coating did not show signs of wear and could not be removed using a standard ink pen eraser.

	Figure 2. Left: An uneven submetallic coating with an irregular pattern is revealed with reflected light. The white dashed box represents the area shown in the right photo. Field of view 3.33 mm. Right: Under brightfield illumination, a part of the left table facet shows whitish surface structures surrounding the metallic luster domains. Field of view 1.31 mm. Photomicrographs by Kazuko Saruwatari.

	Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) chemical analyses detected elements such as B, Li, and Na, indicating elbaite tourmaline. However, strong early (near-surface) peaks of elements Pt, W, and Mo, which are not normally contained in natural tourmaline, were detected. We determined that this chemistry difference probably resulted from the submetallic surface coating. As with Pt- and Pt-related coatings, it is possible that the coating was used to improve abrasion resistance (e.g., K. Schmetzer, “Surface treatment of gemstones, especially topaz – an update of recent patent literature,” Journal of Gemmology, Vol. 31, No. 1, 2008, pp. 7–13) or to assist with scanning electron microscopy (SEM) observation (e.g., I. Stokroos et al., “A comparative study of thin coatings of Au/Pd, Pt and Cr produced by magnetron supporting for FE-SEM,” Journal of Microscopy, Vol. 189, No. 1, 1998, pp. 79–89).

	The reason for applying this coating is unknown. This is the first time GIA’s laboratory has observed coated Paraíba tourmaline. Source: GIA @topic:12


Title: Unique Circuit Board–Like Surface Pattern on Tourmaline Abstract: Figure 1. This 0.70 ct tourmaline shows unique surface patterns. Photo by Shunsuke Nagai.

The Tokyo laboratory recently received a 0.70 ct blue-green oval modified brilliant measuring 6.62 × 4.99 × 3.10 mm (figure 1). Standard gemological testing yielded a refractive index of 1.620–1.640, uniaxial interference pattern, and a hydrostatic specific gravity of 3.10, all consistent with tourmaline. No Cu was detected with energy-dispersive X-ray fluorescence (EDXRF). UV-Vis-NIR spectrometry did not show Cu absorption bands but did show a strong Fe absorption. This stone, therefore, did not meet the requirement to be designated as a Paraíba tourmaline, whose dominant coloring agent of green/blue must be Cu (LMHC Information Sheet #6, 2012).

Figure 2. The circuit board–like features point mainly in three directions on the crown (left) and are aligned in only one direction on the pavilion (right). Photomicrographs by Yuxiao Li; field of view 3.95 mm (left) and 2.91 mm (right).

Figure 3. Some features on the table facet, photographed in reflected light, were parallel to the polish lines. Photomicrograph by Yuxiao Li; field of view 3.80 mm.
Microscopic observation revealed a unique networked pattern, resembling the pattern of a circuit board, covering the overall surface of the stone. The surface features mainly pointed in three directions on the crown but did not show a clear three-directional pattern on the pavilion (figure 2). Viewed under reflected light, some features at the table facet were parallel to the “polish lines” (figure 3). No evidence of coating and no color concentration along the pattern were found. The conoscope image with crossed polarized filters showed that the table facet was perpendicular to the c-axis. Because tourmaline belongs to the trigonal crystal system, the features appeared to be crystallograpically aligned. That could also explain why the patterns were different between the crown and the pavilion.
We also observed tension cracks surrounding fluid inclusions, which indicated the possibility of heat treatment. In addition, this color of tourmaline is commonly heat treated to improve its color.

Figure 4. Features similar to the tourmaline’s superficial fractures have been seen on the surface of rough crystals such as this Burmese spinel with fractures that likely result from strain in the crystal lattice. Photomicrograph by Nathan Renfro; field of view 2.35 mm.
Because the unique patterns were related to the crystal structure, they may have been caused by thermal shock related to heat treatment and/or acid etching. Similar crystallographically aligned surface features have been found on rough crystals of Tanzanian tourmaline and Burmese spinel (figure 4; N. Renfro, pers. comm., 2021). What caused this pattern and how it came to be revealed on a faceted stone remains a mystery. More samples and further experiments are needed to unravel the cause of these unique and interesting patterns. Source: GIA @topic:12


Title: Kathryn Kimmel Abstract: In Kathryn Kimmel’s nearly 30 years as head of GIA’s marketing and public relations efforts, she radically improved the Institute’s visibility in the trade and the public eye. Kimmel established the annual GIA Jewelry Career Fairs and the consumer outreach program on the Institute’s gem identification and grading reports and the 4Cs. She was the first woman on GIA’s executive team, beginning as director of marketing in 1990 and retiring as senior vice president and chief marketing officer in 2019.
A third-generation jeweler, Kimmel learned repair and sales at her parents’ Los Angeles store. She visited GIA as a child—while her father was taking the Institute’s courses—and met Richard T. Liddicoat and Robert Shipley Jr. She even spent her birthdays at the California Jewelers Association’s annual shows. Yet she resisted going into the family business and took a detour to major in theater arts in college and work in entertainment production.
By 1990, when Kimmel met GIA’s then-president Bill Boyajian, she had returned to the industry, managed the family store, and risen to vice president of marketing for manufacturer Nova Stylings. At Nova she learned marketing principles from renowned expert Guy Kawasaki. Boyajian was looking for a new director of marketing and was impressed by her background and drive. She joined GIA that summer.
Kimmel established a public relations department, streamlined and modernized GIA’s brand identity and marketing materials, and revamped the advertising strategy. She directed the launch of the Institute’s first website and with Boyajian wrote the Institute’s first mission statement. When she found herself advising students about how to transition into the trade, she recognized the need for a career fair. With the support of the Jewelers 24 Karat Club of Southern California, GIA’s first career fair was held in Santa Monica in 1991. As the industry’s largest recruiting event, it has expanded to five GIA locations and been an avenue for countless GIA graduates to begin their careers.
“My heart will forever be with the students—seeing them study at GIA, coming to GIA’s Jewelry Career Fair and becoming industry leaders has been one of the most rewarding parts of my job,” Kimmel said.
In the years since, Kimmel increased the Institute’s participation in international trade shows and industry events, co-chaired its International Gemological Symposiums, and steered GIA’s marketing activities in an ever-evolving industry. Echoing her first visit to GIA decades prior, she grew to see Liddicoat as a mentor and father figure and refers to Shipley as one of her heroes.
In 2006 GIA honored Kimmel with the Richard T. Liddicoat Award for Distinguished Achievement, its highest tribute. Other recognition includes the American Gem Society’s Triple Zero and Distinguished Service awards, the Jewelers 24 Karat Club Excellence in Service Award, the YWCA’s Tribute to Women in the Industry (TWIN) award, and the Women’s Jewelry Association Award for Excellence in Promotion. In 2016 she was named one of Luxury Daily magazine’s 25 “Luxury Women to Watch.” Kimmel is a founding member and past president of the WJA’s Los Angeles chapter, and has served on the boards of WJA, the Jewelers 24 Karat Club of Southern California and the Jewelry Information Center. Source: GIA @topic:11


Title: Book Review: Real or Fake? Moldavites Abstract: By František Funda, softcover 92 pp.illus.publ. by powerprint s.r.o., Prague, 2015.

	Moldavite is an impact glass, produced when terrestrial silica is fused in the intense heat and pressure created by the crash of large meteorites. The identification of faceted moldavite is quite simple. Besides their flow structure and abundant bubbles, moldavites contain “wires” or “corkscrews” of lechatelierite, a high-temperature form of SiO2 that is very easy to see due to its low refractive index. Since identification of unfaceted material can be a real challenge, I was looking forward to finding out whether the book would provide additional data on this subject.

	In Real or Fake? Moldavites, author František Funda discusses numerous topics pertaining to the material in a reader-friendly format. The book covers the materials’s gemological properties and cut and raw moldavites. It then branches out into material from the Besednice deposit in the Czech Republic (famous for its beautiful raw moldavites), handmade glyptic sculptures in natural moldavite, tumbled and broken moldavite, and moldavite in jewelry. It has appendices with an extensive list of worldwide available gemological laboratories and chemical composition of moldavites based upon analytical results from other authors.

	The original Czech text has been translated by a non-native English speaker. This explains the use of the German word schlieren to describe the swirls in the inner structure section.

	The chapter on raw material is informative, as the identification of moldavite with a natural-looking surface is rather difficult. The surface feature of natural moldavite is caused by natural etching, and the author invites us to look for evidence of this process such as sharp protrusions. Other features of natural moldavite include lechatelierite needles and atypical shapes on the surface such as channels, open-ended bubbles, and residues of clay or ferruginous sandstone from the sediment matter in which the moldavites are found. What especially distinguishes a Besednice moldavite from all of the others are the sharp spikes, which have given these moldavites the very unglamorous nickname of “hedgehog.”

	A full chapter is devoted to moldavite’s gemological properties and how they may be used to identify natural specimens. Funda writes that the material’s RI and relative density overlap with artificial glass. While natural moldavites are inert to long-wave and short-wave UV, some imitations have a chalky fluorescence in short-wave UV.

	The text is illustrated with color images throughout, but unfortunately the photos lack any kind of indication on the size of the specimens. The book is being advertised as the ultimate guide for both laymen and professional gemologists that will teach you how to recognize an authentic moldavite from an imitation. This is obviously untrue, as readers are invited to read more about the inhomogeneity and the inner structure of moldavites in a forthcoming book called Facts about Moldavites. The author is passionate about the subject, but the title of the book sets a high expectation which it did not meet. Source: GIA @topic:3


Title: Tourmaline Crystals on Burmese Ruby Abstract: Bluish green tourmaline crystals and white calcite on a Burmese ruby. Photo by Charuwan Khowpong; field of view 2.48 mm.

During a GIA field expedition to Mogok, Myanmar, a tiny but interesting sample was acquired. This 0.552 ct ruby was purchased from local Kanase miners who process the tailings of the larger mines in the Kyatpyin Valley, just west of the town of Mogok. The ruby is associated with pure white calcite and bluish green tourmaline (see above).

Many rubies form in marble, especially in the deposits related to the Himalayan orogeny (Afghanistan, Tajikistan, Myanmar, and Vietnam), so calcite as an inclusion or associated mineral with these gems is common. While tourmaline in combination with ruby is not unheard of, it is a relatively unusual combination. Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) chemical analysis showed that the tourmaline was a Na-Mg-rich dravite. Tourmalines are of great interest to geologists because their isotopic and trace element composition are potentially strong indicators of the formation environment of the tourmaline and the associated minerals, in this case ruby. Source: GIA @topic:2


Title: Occurrence of Petrified Woods in the Russian Far East: Gemology and Origin Abstract: Figure 1. Marble polar bear with silver fish on a petrified opalized wood stand. Photo by Svetlana Kultenko; courtesy of Anton Akulenko.

Petrified woods are used all over the world as an excellent material for souvenirs, jewelry, and spectacular collectible pieces. A new occurrence of petrified wood was discovered in 2014 in the Primorsky Krai region of the Russian Far East, near the village of Kiparisovo. The fossils were found in the northwestern part of a sand and gravel quarry, at the contact of rhyolitic volcanic ash tuffs and basalts overlapping them. The sample sizes varied from several centimeters to two meters.
Local jewelers started using the wood fossils as stands for souvenirs (figure 1) and polished collectible samples. The petrified wood appeared in regional jewelry stores and attracted Chinese tourists’ attention, creating demand for the raw material from China’s market.

Figure 2. Cabochons of petrified wood from the Russian Far East. Photo by Dmitrii G. Fedoseev.
More than a hundred samples were studied at the Analytical Center of the Far Eastern Geological Institute of the Far Eastern Branch of the Russian Academy of Sciences (FEGI FEB RAS). We examined the mineral composition, structure, and gemological characteristics using standard gemological equipment, a Nikon E100 POL optical microscope, and a MiniFlex2 X-ray diffractometer (XRD). Several examples of petrified wood were found: white, yellowish, marble-like, chalcedony-like, banded, banded chalcedony-like with brownish growth rings, partially carbonized, and black coalified (figure 2).

Figure 3. Top: Schematic cross section of a conifer’s trunk showing the transection (A), radial section (B), tangential section (C), annual ring (AR), resin ducts (RD), wood rays (WR), bordered pits (BP), and middle lamellae (ML). Bottom left: Transection of petrified wood with wood rays (horizontal lines), resin ducts, and annual ring; field of view 5.5 mm. Bottom center: Radial section of petrified wood with wood rays (horizontal lines) and tracheids with bordered pits (round-shaped); field of view 2.7 mm. Bottom right: Tangential section of petrified wood with chains of middle lamellae; field of view 5.5 mm. Photomicrographs by Dmitrii G. Fedoseev.
The refractive indices of polished plates ranged from 1.40 to 1.54 in different areas and corresponded to chalcedony, opal, and quartz. Luminescence was weak bluish or greenish under short-wave UV; most samples were inert under long-wave UV. Samples had a fibrous cellular structure. The shape of the cells (tracheids) was angular, rectangular, and sometimes subsquare (figure 3, bottom left). The transections of the samples showed very narrow single-row horizontal wood rays. Vertical resin ducts that looked like white dots were located in the latewood area of the annual rings (vertical dark band) (figure 3, bottom left). On the radial sections of the samples, we observed wood rays (horizontal lines) and bordered pits (round-shaped pores) (figure 3, bottom center). Middle lamellae (chains-like cells) were seen on a tangential section of petrified wood (figure 3, bottom right).
The absence of vessels, the unique type of wood rays and tracheids with bordered pits, the character of the middle lamellae, and the presence of vertical resin ducts indicated that these samples belonged to coniferous plants. X-ray diffraction analysis showed that all the varieties of petrified wood had an opal-cristobalite-tridymite composition.
The geology of the area allowed us to imagine the formation conditions. As a result of catastrophic volcanic eruptions of rhyolitic magmas as glowing ash clouds, and late effusions of mantle magmas, thick layers of volcanic ash and overlapping basalt flows were formed. The basalt lava flows outpoured into the water basin with a temperature exceeding 1000°C. Lavas overlapped the flooded trunks and thick bottom sediments of ash silts. When the basalt melt came into contact with water, the surface of the lava flow instantly quenched with the formation of pillow lavas. The space between the pillow lavas was filled with clastic glassy rocks known as hyaloclastites.

Figure 4. Left: Part of a petrified wood. Right: Opalized petrified wood sample with play-of-color. Photos by Dmitrii G. Fedoseev.
Thus, the flooded trees were under the hyaloclastites and pillow lavas. Some trees, under the weight of a lava flow, had taken a vertical position. Some trunks that sunk in hyaloclasts were charred, while trunks in ash silts remained unchanged. During silicification, the charred parts of the trunks acquired a black color and the uncharred parts became white, light yellow, to brownish (figure 4). Buried trees underwent strong deformation with flattening of the trunks, splitting, and fragmentation of wood.
The main source of silica when replacing the cells of trees by quartz or opal was ash silts. This was promoted by a low-alkaline water-saturated volcanic ash with a high SiO2 content (over 72 wt.%). The silicon-containing aqueous solutions penetrated woods that, under anaerobic conditions, represented local geochemical barriers where precipitation of free silica replacing plant cells occurred. Depending on the concentration of silicon in the solution in plant cells, the deposition of opal, chalcedony, or quartz occurred. The foregoing description allows us to imagine a majestic picture of how Nature created this wonderful combination of the worlds of plants and stones. Source: GIA @topic:1


Title: Yellowish Green Diopside and Tremolite from Merelani, Tanzania Abstract: Four similar-appearing yellowish green samples from Block D at Merelani, Tanzania, were identified as diopside and tremolite. The gems are identical in color, but their standard gemological properties are typical for calcic pyroxene and amphibole. The identification of the diopside was made with Raman spectroscopy, while single-crystal X-ray diffraction and electron-microprobe analyses were used to confirm the amphibole species as tremolite. Absorption spectroscopy (in the visible–mid-infrared range) revealed that the two gem materials are colored by V3+, Cr3+, or both. Source: GIA @topic:12


Title: An Update on the Ural Emerald Mines Abstract: The emeralds of the Ural Mountains, in what is now called the Russian Federation, have been known for more than 160 years. They were famous worldwide during the early part of the 20th century. However, because little information was made available about these deposits in recent years, many in the gem industry concluded that they had been exhausted. This article reveals that mining and processing are ongoing in the region, with significant reserves of gem-quality emerald still to be exploited. In addition, the reopening of four mines promises to increase commercial production. Source: GIA @topic:1


Title: The Sapphires of Penglai, Hainan Island, China Abstract: The sapphire deposit at Penglai, on Hainan Island, is potentially the largest in China. Gem-quality sapphires, at least one as large as 35.5 ct, have been found in alluvial gravels approximately 2 km southeast of the city of Penglai. Gem-quality zircon and a few pieces of what might be considered ruby have also been recovered in the course of the geologic study of this area, which has not yet been commercially developed. The average size of the sapphires is 2—5 mm. They are similar in appearance and gemological properties to sapphires from Australia, Thailand, and Kampuchea. Source: GIA @topic:1


Title: Artistry in Rock Crystal: The Van Pelt Collection Abstract: Harold and Erica Van Pelt of Los Angeles are known worldwide for their superb color photography of gems and minerals. A well-kept secret, however, has been their remarkable proficiency in the lapidary arts, specifically in the production in traditional styles of many important rock crystal objects, including candlesticks, vases, paperweights, and polished quartz crystals containing various mineral inclusions. Agate, amethyst, and other gemstones are also employed. For the most part, the machinery used to create these objects was designed or modified by the Van Pelts themselves and includes devices for sawing, grinding, and polishing. A step by-step procedure for making a hollow ostrich egg, completely covered by triangular facets, is explained. Source: GIA @topic:9


Title: Triplite Inclusions in Quartz from Yaogangxian, China Abstract: Figure 1. A 30.80 ct faceted quartz containing pinkish orange inclusions. Photo by Hongtao Shen; courtesy of Jinrui Dong.
Quartz is host to a wide variety of inclusions. Recently, the authors examined a 30.80 ct transparent faceted quartz with several pinkish orange crystal inclusions, from the town of Yaogangxian in Hunan Province, China (figure 1). This quartz was cut from a rough stone collected by a local miner. In this quartz, the pinkish orange inclusions were unique and attractive.

Figure 2. Magnification of pinkish orange triplite in a transparent quartz from Yaogangxian in Hunan Province, China. Photomicrograph by Hongtao Shen; field of view 11.15 mm.
After grinding, one of these inclusions was exposed to the surface (figure 2). Raman spectroscopy and energy-dispersive X-ray fluorescence were used to identify the inclusion as triplite.
Triplite, (Mn2+,Fe2+)2PO4(F,OH), is a rare phosphate mineral that can be found as either a gem material or an inclusion. Most triplites are produced in pegmatite, as with quartz. Triplite inclusions have been reported in topaz (Summer 2016 G&G Micro-World, p. 205) and beryl (Spring 2020 G&G Micro-World, p. 145). To the best of our knowledge, this is the first discovery of triplite as an inclusion in quartz. Source: GIA @topic:2


Title: Attractive Composite Quartz Beads Abstract: Figure 1. This string weighing 145.70 carats consists of attractive blue and golden brown beads measuring approximately 7.91–8.48 mm in diameter. The beads were identified as composites fashioned from pieces of dyed quartzite held in a polymer matrix. Photo by Gagan Choudhary.

              The Gem Testing Laboratory in Jaipur recently received a 145.70 carat string of attractive blue and golden brown spherical beads (figure 1) measuring approximately 7.91–8.48 mm in diameter. The beads were readily identified as artificial by their appearance, which consisted of metallic golden brown veining and concentrations of blue color against a whiter body. Further tests were performed to identify the blue areas.

The measured RI was approximately 1.54. The beads displayed a patchy chalky blue reaction to short-wave UV and were inert to long-wave UV. Their Chelsea filter reaction was red, and under the desk-model spectroscope they displayed a band at approximately 650 nm. Under magnification, the blue areas displayed fluid inclusions that gave the beads a cloudy effect. In addition, the abundant fractures showed the presence of dye (figure 2) that was responsible for the beads’ blue color. Such features are commonly observed in dyed quartzite, but these were not sufficient to prove its identity. The golden brown areas, which consisted of fine flakes (again, see figure 2) held in a soft polymer, were later identified by EDXRF spectroscopy as copper and zinc composites. Similar composites in which the components are held together in a polymer matrix have been known in the trade for several years now (see G. Choudhary, “A new type of composite turquoise,” Summer 2010 G&G, pp. 106–113). Also present were thick layers of polymer along the edges of the blue and golden brown areas, which appeared green due to the overlap of the blue dye with the golden flakes. Raman spectroscopy confirmed that these blue portions were quartz.

Figure 2. Color concentrations of blue dye were easily visible along the fractures against a white background, while the golden brown areas were composed of copper-zinc based fine flakes. Also note the greenish polymer along the edge of the golden brown and blue areas. Photomicrograph by Gagan Choudhary; magnified 48×.
Recognizing these beads as composites was straightforward, but identification of the components required Raman and EDXRF spectroscopy. Although these beads were obviously created to offer something fancy and attractive to consumers at a low price, clear and complete disclosure remains imperative. Source: GIA @topic:13


Title: Metal Sulfide in Pyrope Abstract: Figure 1. The prominent sulfide inclusion in this 2.02 ct pyrope is clearly visible under the table facet. Photo by Kevin Schumacher.

	The 2.02 ct “inclusion gem” shown in figure 1 is not only spectacular to inclusion enthusiasts, but also a scientific mystery. This vanadium- and chromium-bearing pyrope was cut from one of the samples featured in G&G’s Winter 2015 issue (Z. Sun et al., “Vanadium- and chromium-bearing pink pyrope garnet: Characterization and quantitative colorimetric analysis,” pp. 348–369). The stone was faceted by Jason Doubrava (Poway, California) to display a relatively large, euhedral sulfide crystal inclusion. Sulfide crystals were observed in several of the samples in the 2015 study; the exact nature of the inclusions could not be determined by Raman analysis, but all displayed a metallic luster in surface-reflected light. Magnification also revealed a cloud of minute acicular inclusions resembling rutile surrounding the crystal (figure 2). Along with the elements expected for pyrope, such as Si, Al, Mg, Mn, and Fe, energy-dispersive X-ray fluorescence (EDXRF) analysis detected peaks for sulfur and rhodium. While sulfur would be expected in a metal sulfide, the rhodium peak is a mystery. Rhodium sulfide does exist, but explaining the presence of rhodium in this garnet would require destructive testing. In this case beauty trumps science, because this gem is truly a wonderful addition to the collection of this inclusionist and will thus remain a gemological curiosity.

Figure 2. A cloud of extremely fine acicular inclusions in the pyrope surrounds the sulfide when viewed under the microscope with diffuse reflected light. Photomicrograph by Nathan Renfro; field of view 5.41 mm. Source: GIA @topic:3


Title: Faceted Milarite Abstract: Figure 1. This 2.07 ct oval brilliant is the first faceted milarite examined by the Carlsbad lab. Photo by Diego Sanchez.

Recently the Carlsbad lab received a light yellow 2.07 ct unknown gemstone (figure 1). The measured refractive index was 1.548–1.550 with a birefringence of 0.002. The specific gravity, measured hydrostatically, was 2.52. These properties were consistent with the mineral milarite, which was confirmed by Raman spectroscopy (figure 2). The stone showed planar/patterned liquid inclusions resembling a honeycomb pattern and also contained needle-like inclusions.

Figure 2. Raman spectroscopy confirmed the gem to be milarite.
Milarite is fairly rare but gives its name to a somewhat large group of silicates, namely the milarite-osumilite group. This group is composed of similar cyclosilicate minerals that are very rare and obscure. Crystals are generally small and often have a muted green or yellow color, and they occur as well-formed prismatic hexagonal crystals. Milarite is a hexagonal-dihexagonal dipyramidal mineral with a composition of K2Ca4Al2Be4Si24O60•H2O. It forms as a primary mineral in granitic pegmatite, low-temperature hydrothermal veins, and alpine clefts.
The mineral was named by Gustav Kenngott (1870) after he mistakenly identified its provenance as Val Milar, located in eastern Switzerland. The original specimens actually came from neighboring Val Giuf. Even though milarite was the first newly described mineral from a Swiss Alpine fissure, it took more than 60 years to identify the mineral’s true chemical nature, in particular its Be content. Milarite was originally known as a green mineral, until fine yellow crystals were discovered in Mexico in 1968. Larger Mexican crystals with transparent areas have occasionally been faceted into small gems with a pleasing appearance, but these are exceedingly rare.
Outside of Switzerland, notable occurrences have been recorded in Brazil, Mexico, Germany, Russia, Canada, Italy, Norway, and the Czech Republic. Nevertheless, this is the first example of faceted milarite ever examined by the Carlsbad laboratory. Source: GIA @topic:2


Title: Imitation Rubellite Boulders Abstract: Figure 1. Left: The two sections of the larger “boulder” were glued together to show the original size and form of the 2 kg imitation tourmaline rough. The length of the boulder was approximately 16 cm. Right: The boulder was cut, revealing the metal bar insert. Photos by Emanuele Costa.
Recently, RAG Gemological Laboratory in Turin received two “boulders,” weighing approximately 2.0 and 0.7 kg, reported to be rubellite tourmaline rough from Madagascar. The larger one was cut into two parts and found to be a resin imitation made heavier using a metal bar insert (figure 1). The smaller one was half of a boulder, again containing a metal insert. The resin matrix was colored bright cherry red and clearly noticeable in direct sunlight or using a small handheld light. The external appearance of both specimens was that of alluvial boulders that had floated and eroded over a period of time in riverbeds. The surface of each was rough with pits and fissures, and the voids were filled with material with an ochre appearance, very similar to clay and soils (figure 2). Due to the specimens’ mass, the authors could not use an immersion balance, so an approximate density was determined by weighing the two parts of the larger boulder and weighing the corresponding amount of water displaced by immersion. The density was about 2.9, close to the specific gravity of natural rubellites (3.0–3.2).

Figure 2. Details of the imitation boulder’s surface, with pits, cavities, and fissures filled
with a clay-like material. Photo by Emanuele Costa.
During an examination of a thick slab (about 1 cm) taken from the larger boulder using a circular saw with a diamond blade, different phases of preparation of the boulder imitation were observed. These stages were suggested by the presence of differently colored resin blobs around the metal bar, enveloped by the outermost portion of plastic material with a more intense cherry red color (figure 3). The resulting product was probably scarred on the surface, tumbled, and finally immersed in a mix of mud and clay. Infrared (IR) spectroscopy investigation indicated the material was styrene-based resin, with a phthalate compound added for hardening. The resin was very similar to that used for fiberglass preparation, and it is easily found on the market. The metal insert, analyzed with EDS, was ordinary lead.

Figure 3. A transparency scan of an imitation boulder section; the black region is the
metal insert. Color changes in different areas of the boulder suggest a multiple-step
preparation involving various resin batches. The resins may have been worked in a
semifluid or solid but malleable form, because some lack of adhesion—and the creation
of voids—is noticeable. Photo by Emanuele Costa.
Many features easily distinguished these imitations from natural rubellites. The surface hardness was very low, and the resin used for the imitation partially melted at a relatively low temperature; therefore, a hot needle was enough to confirm the organic character of the mass. Acrid and pungent smoke was released when the hot needle made contact with the red-hot metal. Moreover, the plastic mass contained air bubbles (figure 4) that were easily seen from a smooth portion of the surface when using a loupe with intense illumination.

Figure 4. Air bubbles are randomly scattered in various portions of the resin matrix.
Photo by Emanuele Costa.
These tests are not easily managed in the field, however. The provenance of these boulders was most likely Madagascar, but no other reliable information was provided. Such boulders are rumored to have been mixed in with batches of natural rubellite boulders from alluvial deposits. Such imitations, especially if wet and muddy, could go unnoticed and increase the total weight of a rough stone batch. Source: GIA @topic:2


Title: Coral Inclusions in Plastic Abstract: Figure 1. This 37.50 ct plastic bead contained visible fragments of carbonate-type coral (the lighter spots). Photo by Gagan Choudhary.

Composites assembled from opaque-to-translucent and transparent gem materials such as turquoise, chalcedony, opal, chrysocolla, tourmaline, and peridot have become popular over the past few years, as evidenced by the number of samples received for identification at the Gem Testing Laboratory in Jaipur, India. Recently, we examined an orangy red bead of plastic (figure 1) with embedded fragments of coral.

The round bead weighed 37.50 ct and measured 20.62 × 20.57 × 14.02 mm. The bead was represented as coral, but its smooth texture along with the luster was sufficient enough to rule out that possibility. A few spots of lighter color (again, see figure 1), visible to the unaided eye, made it more interesting. Under strong fiber-optic light, minute transparency was observed, while microscopic examination revealed numerous gas bubbles scattered throughout the bead. Sharp boundaries between the lighter spots and the host bead suggested that these spots of lighter color were actually fragments of some other material. These randomly oriented fragments also displayed some concentric radiating structures (figure 2, left), typically seen in carbonate-type corals. Some chips also showed elongated sections (figure 2, right), along with some whitish to faintly colored areas.

Figure 2. Some of the fragments embedded in the plastic bead displayed concentric radiating structures (left), typically seen in carbonate-type coral, while others show elongated sections (right). Also note the sharp edges and whitish to faintly colored areas of the fragments. Photomicrographs by Gagan Choudhary; field of view 5.08 mm.
Although the bead was obviously an artificial product, its major component was still to be identified. A spot refractive index of approximately 1.53 and hydrostatic specific gravity of 1.97 were obtained. Under UV light, the bead fluoresced orange, with a stronger reaction to short wave than long wave; a desk-model spectroscope revealed a broad absorption band from the violet to yellow-orange region. Raman spectroscopy (figure 3) confirmed the major component of the bead as plastic, while the grains were identified as carbonate. We did not detect any carotenoid-related peaks, which have been suggested as the cause of color in pink-to red-coral (C.P. Smith et al., “Pink-to-red coral: A guide to determining origin of color,” Spring 2007 G&G, pp. 4–15). On the basis of Raman spectra and concentric radiating structure, the sharp fragments were identified as white coral.

Figure 3. Raman spectra using 785 nm laser confirm that the major component of the
bead is plastic (blue trace), while the grains are a carbonate such as calcite (red trace).
The lack of carotenoid-related peaks suggests the use of white coral fragments.
Coral-plastic composites have been reported previously (e.g., Fall 2008 Lab Notes, p. 253). Further, orange-red plastics have also been known as coral imitations for decades. This specimen turned out to be notable because of the use of coral fragments as inclusions; however, we could not clearly understand its purpose. Source: GIA @topic:14


Title: Grandidierite from Madagascar Abstract: Figure 1. This grandidierite sample, weighing 8.26 ct and measuring approximately 14 × 11 × 7 mm, was acquired in Madagascar by one of the authors. Photo by Victoria Raynaud.

Grandidierite was first described in southern Madagascar in 1902. The mineral is very rare; gem-quality material of facetable size was almost unheard of in the market before the summer of 2015.

In September 2015, GIA’s Bangkok lab issued identification reports for several faceted grandidierite samples, which reached the consumer market the following month. The submitted stones ranged from 0.9 to 2.3 ct. Around the same time, one of the authors (VP) returned from a field expedition to Madagascar, where he had received some unidentified stones from Jack Mampihao. Included with the material was one unfamiliar rough fragment, weighing 8.26 ct and measuring approximately 14 × 11 × 7 mm (figure 1), which Mr. Mampihao said came from a mine near Tolianaro, in the Tranomaro area at the southern tip of the country. Mr. Mampihao reported that a large number of these stones were found, but they were unknown to local miners and dealers. Currently, we have no information about the exact amount and quality of this material.

Gem-quality grandidierite has been attributed to deposits in southern Madagascar, near Tolianaro (formerly Fort-Dauphin), and in Sri Lanka. With a chemical formula of (Mg, Fe2+)Al3(BO3)(SiO4)O2, the mineral belongs to the orthorhombic crystal system. All anisotropic minerals display pleochroism to varying degrees; grandidierite shows dark blue-green, dark green, and colorless (M. O’Donoghue, Gems: Their Sources, Descriptions and Identification, 6th ed., Butterworth-Heinemann, London, 2006). Its bodycolor ranges from bluish green to greenish blue (A. Thomas, Gemstones: Properties, Identification and Use, New Holland Publishers Ltd., London, 2009). Grandidierite has an RI of 1.590–1.639 (O’Donoghue, 2006) and a birefringence of 0.037–0.039. Its SG is close to 2.98 (O’Donoghue, 2006; Thomas, 2009), but this value may vary between 2.85 and 3.00, according to other sources (H. N. Lazzarelli, Gemstones Identification Blue Chart, 2010, www.gembluechart.com). A previous study has shown an absorption line at 479 nm (K. Schmetzer et al., “The first transparent faceted grandidierite, from Sri Lanka,” Spring 2003 G&G, pp. 32–37). In that study, Raman spectroscopy was carried out on a single gem-quality grandidierite, and the same sample was subjected to composition analysis. The gemological properties of our rough sample were compared with the literature; the results are given in table 1.

The stone was analyzed using LA-ICP-MS (table 2). Three spots were analyzed and compared to data obtained by Schmetzer et al. (2003). The sample had a very low iron content compared to the earlier study. This may be explained by the elevated Mg content, since the two elements often substitute for each other. An exact comparison of the datasets should be done with care, since different techniques were used to analyze the composition. Schmetzer (2003) used electron microprobe analysis (EPMA), while the present authors used LA-ICP-MS. Using a diffraction grating handheld spectroscope, we observed a very faint line in the blue region of the visible spectrum (approximately 470–490 nm). The Raman spectrum matched closely with the RRUFF spectrum for grandidierite (figure 2). Both spectra were taken on unoriented samples.

TABLE 2. Analysis of a previously studied grandidierite and a recent sample from Madagascar (wt.%).

Oxides
			(wt. %)

Grandidierite from
			Schmetzer et al. (2003)a
Recent sample from
			Madagascarb,c

SiO2
20.20

16.41 (0.05)

Al2O3
52.64

53.89 (0.51)

B2O3
11.91

12.33 (0.58)

Cr2O3
0.07

0.01 (0.00)

FeO
1.71

0.30 (0.05)

MnO
0.03

0.01 (0.00)

MgO
12.85

17.01 (0.32)

Total
99.41
99.95

aElectron microprobe analysis (EPMA), with total iron as FeO. TiO2, V2O3, and CaO were detected (each 0.01%) but are not included here.
bLaser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS).
cThe standard deviations are listed between parentheses.

Figure 2. This comparison of the Raman spectra of the grandidierite from Madagascar
(blue spectrum) and a sample in the RRUFF database (black spectrum) provides further
confirmation that the previously unidentified material is grandidierite.
All the characteristics of the unknown stone obtained in Madagascar matched with grandidierite. Some values fell outside the previously reported ranges, but they were within acceptable ranges for a mineral that has not been studied in depth and for a sample that is from an unknown deposit. With field collection and lab testing pointing to new sources of grandidierite, this could be a step toward a larger market presence for this material. Source: GIA @topic:2


Title: Update on the Scorpion Tsavorite Mine Abstract: Figure 1. The new production from the Scorpion mine includes these 6.48 ct and 3.43 ct tsavorites. Photo by Robert Weldon/GIA, courtesy of Bridges Tsavorite.

	At the AGTA show, Bruce Bridges (Bridges Tsavorite) detailed current activity at the Scorpion mine in Kenya and showed some new production (figure 1). The mine lay dormant for more than five years after the 2009 murder of owner Campbell Bridges, who originally discovered tsavorite. While waiting for the courts to hand down verdicts, the Bridges family and their employees were the target of numerous death threats. In January 2015, after four of the eight defendants received sentences of 40 years without parole, the mine reopened with a larger scale of operations than ever before.

	Activities expanded for a variety of reasons. As a corporation rather than a small family operation, the Bridges family felt that they were less of a target for criminals. The Bridges also found that the demand for tsavorite rose exponentially during the mine’s closure. With a limited supply and greater popularity, the higher selling price has made larger-scale mining more feasible.

	There are 80 to 100 workers at the Scorpion mine, three times the number employed when it closed in 2009. The miners work in continuous shifts seven days a week. Mechanization has increased to include more powerful generators and 15-kilowatt fans for ventilation in the tunnels. The tunnel is now below the oxidized zone, requiring a blast approximately every half meter of forward progress. The stronger fans allow the ventilation system to remove the smoke and dust in about two hours rather than the full day previously needed. They have also invested heavily in trucks, buildings, jackhammers, drills, and more explosives. Campbell Bridges’s original campsite and tree house remain intact.

	The main focus of the current operation is the Bonanza tunnel, also called tunnel 4, which was Scorpion’s most prolific tunnel in the 1980s. They are also working the adjacent tunnel 2, the largest producer in the 1990s. Tunnel 2 produced five kilograms of facet-grade material over one carat from one pocket during this period. A few kilometers from Scorpion is mine GG2, which typically produces tsavorite with lighter tones. GG2 is an open-cast operation on a hill, with plans to move into a tunnel phase later this year. An untouched surface deposit near tunnels 2 and 4 is also in development for open-cast mining, and the Bridges have high hopes for it, as the ratio of yield to waste is high on new deposits. Other sources include GG3, which is several kilometers away and primarily uses tunnel mining, and Snake Hill, which is one kilometer from Scorpion and has been mined by both open-cast and tunnel methods. Snake Hill is also a tanzanite source. These deposits have been put on hold in favor of tunnels 2 and 4 and GG2, as well as the untouched surface deposit.

	There is now greater sophistication and manpower in Bridges Tsavorite’s mining process. The drill team bores large holes in the tunnels and then places the explosives. After the blast, the air is flushed out by the new ventilation system. The removal of waste has been accelerated by the use of a mono winch, which allows up to eight tons of waste to be removed hourly. The waste is hauled to the dump site, where it is separated from the rock face. The mine manager examines the rock face for tsavorite crystals or nodules, also checking for indicators in the reef such as calcite, quartz, and pyrite. Depending on the indications, teams will either continue blasting or extract material with hammer and chisel until the gem body is reached. At that point, miners use sharpened six-inch nails and finally their hands. The gem-bearing specimens are bagged and marked for quality. Once out of the mine, the material is washed and the tsavorite crystals are separated from the host rock. Sieves are used to sort the production by size before it is graded on a sorting table (figure 2). It is then bagged, sealed, and taken to Nairobi by ground or air, depending on its value.

Figure 2. Prior to cutting, the Bridges operation sorts the tsavorite rough into categories by size, color, clarity, and shape. Photo courtesy of Bridges Tsavorite.

	All rough that can be cut to yield a 50-point stone or higher will be cut in-house in Kenya, while the cutting of smaller rough is outsourced. Campbell Bridges learned to cut gemstones in Idar-Oberstein, Germany, and he later trained local Kenyans. One expert cutter on-site is cutting at least 200 stones a month. The Bridges family is proud of their high cutting standards and that they cut most of the high-quality rough in Kenya (figure 3). They also pay a higher export value for finished cut stones than rough, generating more revenue for Kenya. The stones are exported to Bridges Tsavorite’s main sales office in Tucson or to customers worldwide.

	Even with the new investment and expenses, current production is only about 10% higher than before the mine was closed.  Electromagnetic surveys have shown extensive anomalies that indicate tsavorite enrichment zones. Most experts believe the reserves are very good, and Campbell Bridges himself believed he could follow the lines of the Scorpion mine’s saddle reef structure and the nose of the folds for two kilometers while producing tsavorite in pockets. Each tunnel at Scorpion is about 200 meters deep. These reserves must be balanced, however, with the growing cost of delving every meter further into the earth.

Figure 3. The Bridges intend to keep their tsavorite cutting in Kenya for as long as it is economically viable. Photo courtesy of Bridges Tsavorite.

	Bruce Bridges told us that “demand is through the roof” for tsavorite. With its popularity potentially on the rise, Bridges Tsavorite will have to outsource rough. Melee demand is at an all-time high, particularly in China and other Asian countries, where it far exceeds the available supply. Mr. Bridges foresees overall growth for tsavorite through television sales, but he wants to keep as much cutting in Kenya as possible. Challenges for the company include possible changes in the political scene, mining regulations, and the threat of crime and violence. Upon returning to Kenya, Mr. Bridges reported to the authors that death threats had started again. Source: GIA @topic:7


Title: Unusual Fluorescence of a Color-Enhanced Amber Bracelet Abstract: Figure 1. This bracelet contained amber (approximately 10 mm each) that was color-enhanced by a baking process. Photo by Yu-Shan Chou.

              Heat treatment is commonly applied to amber, mainly to improve its color or transparency. The method of heat treatment to enhance the color of amber is informally called a “baking process,” which refers to the process of heating while applying pressure and adding oxygen (Y. Wang et al., “Experimental studies on the heat treatment of Baltic amber,” Summer 2014 G&G, pp. 142–150). Usually, the light yellow amber will be darkened and turned brownish yellow or brownish red by such a process to increase its market value. Amber may also be heated to produce sun spangles and sold as “flower amber” for its popular demand in the market.

A bracelet recently sent to Taiwan Union Lab of Gem Research (TULAB) for identification services contained amber that was pale brownish yellow, transparent, and slightly included (figure 1). Raman spectroscopy and microscopy confirmed the gems to be natural amber with an abundance of sun spangles, which were discoidal fractures caused by heat treatment.

Color enhancement of amber is generally not detectable unless the amber itself has cracks or pores extending to the surface during the baking process, in which case the color usually concentrates in these cracks and pores. Apart from that, amber that is color-enhanced by the baking process mostly shows inert or faint yellow fluorescence under long-wave ultraviolet light; however, such fluorescence may also occur in natural untreated amber.

Figure 2. Magnification revealed that the dark brown color was concentrated in the surface-reaching fractures or sun spangles, yet the sun spangles or fractures wrapped inside the amber were all yellow. Photomicrograph by Shu-Hong Lin.
Microscopic observation of the amber bracelet revealed that the dark brown color was concentrated in all the surface-reaching fractures or sun spangles, but the sun spangles wrapped inside all appeared in a lighter tone of yellow (figure 2). Thus, it was suspected that this amber bracelet had been baked to enhance color.

In addition to the inclusion evidence, the amber bracelet’s long-wave ultraviolet fluorescence reaction unexpectedly presented a relatively bright blue along the ridgelines and inert to faint yellow on the rest of the stone (figure 3).

Figure 3. Under long-wave ultraviolet light, the amber bracelet presented a surprising bright blue fluorescence on the ridgelines and inert or faint yellow fluorescence on the other parts. Photo by Kai-Yun Huang.
This abnormal fluorescence strongly indicated that the amber had indeed been baked to enhance its color and that the ridgelines were worn due to grinding or wearing, which removed the brown surface layer.

This case is worthy of attention because a series of similar items have subsequently been submitted for identification. Traditionally, the color enhancement of amber has been confirmed only by inclusion evidence; however, the abnormal fluorescence of this object offered supporting evidence. Source: GIA @topic:13


Title: Preliminary Study on Rubies Reportedly from Pokot, Kenya Abstract: Figure 1. These eight rubies (0.36–4.38 ct) are reportedly from Pokot, Kenya. Photo by Lhapsin Nillapat.

	In July 2016, Christine Muthama and David Pkosing from Pokot Gems Ltd. in Nairobi submitted eight faceted rubies (figure 1) to GIA’s Bangkok laboratory. The material came from a new operation in the Pokot area, a marble-type deposit in western Kenya that has been largely inactive since the 1960s. This new production could prove to be an interesting source of cabochon- and facet-grade rubies from East Africa.

	The submitted rubies ranged from 0.36 to 4.38 ct and were semitransparent to translucent, with a very fine, milky appearance. Their gemological properties were consistent with ruby from marble-type deposits. The samples displayed strong red fluorescence under long-wave UV radiation and a medium red reaction under short-wave UV. They contained unhealed fractures, planes of negative crystals, fingerprints, and different mineral inclusions such as  apatite, calcite, orange and black rutile, chlorite, pyrite, zircon, and amphibole (figure 2), the last of which is uncommon in marble-hosted rubies. Short needles, boehmite, and clouds of reflective particles were also observed.

	Figure 2. The rubies reportedly from Pokot contained a variety of internal features, including (A) reflective particles, field of view 2.4 mm; (B) very fine short needles, field of view 1.3 mm; (C) very fine milky bands, field of view 4 mm; and (D) an amphibole crystal, field of view 1.3 mm. Photomicrographs by Charuwan Khowpong.

	Since the samples had inclusion features similar to those seen in marble-hosted rubies from Myanmar or Luc Yen, Vietnam, this interesting new Kenyan material could present a challenge in future origin determination studies. Nevertheless, spectroscopy and chemical composition analysis can be used to separate rubies from these deposits. FTIR spectroscopy of all eight samples from Pokot showed the presence of boehmite. LA-ICP-MS analysis revealed a distinguishing trace element composition. The rubies from Pokot had low Fe content (60–252 ppma), along with the following trace element contents: V: 6–11 ppma; Ga: 5–10 ppma; Ti: 29–135 ppma; and Cr: 678–1773 ppma. This combination is quite different from that of known Vietnamese rubies, showing once again that trace element composition is a useful tool for determining the origin of rubies. Source: GIA @topic:1


Title: Rainbow Rays in Rainbow Lattice Sunstone Abstract: Figure 1. Parallel rays of golden, pink, and blue light were observed in this sample of rainbow lattice sunstone. Photomicrograph by Rosie Young; field of view 5.33 mm.

Figure 2. The changing direction of the rays is visible here when the stone is viewed through the same polished face but tilted to a slightly different orientation. Photomicrographs by Rosie Young; field of view 19.27 mm.
While examining a polished sample of Australian rainbow lattice sunstone, the author noticed a series of parallel “rays” illuminated with fiber-optic lighting (figure 1). These rays were initially considered some kind of internal structure within the feldspar. However, the orientation of the rays changed direction when the stone was tilted (figure 2). This indicated an optical effect whereby the fiber-optic light reflected off hematite inclusions and produced a ray of light corresponding to the color of the hematite platelet. This can be observed most easily in the upper right corner of figure 1. Extremely small particles within the sunstone likely allow the path of light to be visible, much like headlights shining through fog. Source: GIA @topic:3


Title: Rubellite with Incredibly Strong “Pink Sleeves” Abstract: Left: Surface-reaching growth tubes and fractures associated with strong pink sleeves, whose color became weaker as they penetrated the stone’s interior; field of view 2.83 mm. Right: Looking down the length of the growth tubes, bleeding of pink color was observed; field of view 1.13 mm. Photomicrographs by Xiaodan Jia.

	GIA’s Hong Kong laboratory recently examined a purplish red cabochon-cut rubellite tourmaline. Standard gemological tests yielded a spot refractive index of 1.64 and specific gravity of 3.06, which are consistent with tourmaline. Magnification revealed strong doubling, fluid inclusions, and parallel growth tubes, all typical of tourmaline. What made this specimen unusual were its localized zones of strong pink coloration surrounding surface-reaching growth tubes and fractures (above left). Bleeding of pink color from the growth tubes into the body of the stone was best observed looking down the length of the growth tubes (above right); the pink color gradually faded away into the surrounding tourmaline host. This type of zoning has come to be known as “pink sleeves.” It is different from dye concentrations, which would only be located inside the surface-reaching growth tubes and fractures.

	Radiation-induced pink sleeves surrounding surface-reaching growth tubes and fractures have been reported in Paraíba tourmalines from Mozambique. The formation is believed to be due to a radioactive solution entering the growth tubes and fractures by capillary action, and the presence of pink sleeves proves that the stone has not undergone heat treatment. (J.I. Koivula et al., “Solution-generated pink color surrounding growth tubes and cracks in blue to blue-green copper-bearing tourmalines from Mozambique,” Spring 2009 G&G, pp. 44–47). To the best of our knowledge, the incredibly strong pink sleeves seen in this rubellite have not been previously reported in either Paraíba or rubellite tourmaline. Source: GIA @topic:2


Title: Four-Rayed Star Chrysoberyl Abstract: Figure 1. Chrysoberyl showing two bands of reflective light displaying four-rayed asterism. Photo by Shunsuke Nagai.
GIA’s Tokyo laboratory recently received a brownish green cabochon set in a white metal ring with numerous near-colorless marquise brilliants and tapered baguettes (figure 1). The stone measured approximately 12.21 × 9.20 × 8.17 mm. Standard gemological testing showed weak green and yellow pleochroism and a spot refractive index reading of 1.75, as well as a strong diagnostic iron-related 444 nm band observed with a handheld spectroscope. These properties were consistent with chrysoberyl. At first glance the cabochon seemed to display chatoyancy, which would make this a cat’s-eye chrysoberyl. However, there was not just a single band of reflected light but two bands intersecting at a 90° angle, so the phenomenon was actually four-rayed asterism.

Figure 2. In the star chrysoberyl, short needles and dense minute particles were perpendicular to each other. The particles reflect light and caused the thick band’s orientation (seen diagonally here). Photomicrograph by Yuxiao Li; field of view 3.7 mm.
Chatoyancy is usually created by light reflecting off of parallel needles or tube-like inclusions in a cabochon-cut gemstone. Microscopic observation revealed two sets of inclusions. One consisted of dense minute particles aligned in one direction producing a thick band of reflected light (oriented diagonally in figure 2). The other set was composed of needles oriented along the same direction as the thick band of light. These needles created a second band of reflected light perpendicular to the orientation of the needles. Together, these reflected bands of light resulted in the unique combination of two intersecting cat’s-eyes.
Four-rayed stars are common in diopside, garnet, and spinel. But they are very rare in chrysoberyl, which makes this stone notable. Source: GIA @topic:3


Title: Star Opal Abstract: Figure 1. This 2.39 ct transparent opal with a light brownish yellow bodycolor possessed a six-rayed star. Photo by Lhapsin Nillapat.

              Opal is best known for displaying play-of-color. It may also display asterism, though star opal has only been reported from Idaho, and a perfect six-rayed star is exceptionally rare (J.V. Sanders, “The structure of star opals,” Acta Crystallographica, Vol. A32, 1976, pp. 334–338). The Bangkok laboratory recently had the opportunity to examine a transparent star opal (figure 1). The 2.39 ct light brownish yellow cabochon displayed a distinct six-rayed star.

Standard gemological testing gave a spot RI reading of 1.43 and a hydrostatically calculated SG of 2.10. When exposed to ultraviolet radiation, the stone fluoresced strong bluish white under long-wave and weak bluish white under short-wave UV. It phosphoresced green after exposure to long-wave UV. Advanced gemological testing by energy-dispersive X-ray fluorescence (EDXRF) confirmed a silica-rich material with some additional trace elements, including aluminum and iron. All of these properties were consistent with opal.

Microscopic examination revealed large parallel planes with play-of-color intersecting to form a hexagonal pattern (figure 2). This is responsible for producing the six-rayed star. This unusual stone serves as a reminder that, unlike asterism in other gem materials, the star in opal is caused by diffraction of light from faults or imperfections in the packing arrangement of silica spheres.

	Figure 2. This photomicrograph of the opal shows the intersection of large parallel planes with play-of-color, producing asterism. Photomicrograph by Charuwan Khowpong; magnified 15×. Source: GIA @topic:12