Title: Emerald/Emerald Doublet Abstract: Figure 1. This 1.81 ct specimen was a natural emerald/emerald doublet. Photo by Claire Ito; field of view 10.5 mm.

	While various combinations of materials are used to form doublet gems, we seldom see doublets consisting of the same materials. Ruby/ruby doublets (Spring 1987 Lab Notes, pp. 47–48; Spring 1996 Lab Notes, p. 49) as well as a tourmaline/tourmaline doublet (Summer 1990 GNI, pp. 165–166) have been reported, but a doublet consisting of two sections of natural emerald has not been previously documented.

	GIA’s Tokyo laboratory recently examined a 1.81 ct transparent green octagonal step cut that measured approximately 7.22 × 6.71 × 5.55 mm (figure 1). Standard gemological testing indicated an SG of 2.71, with an RI of 1.572–1.580 on the crown and 1.570–1.578 on the pavilion. A chromium spectrum consistent with emerald was visible with a handheld spectroscope. Upon first glance, this stone appeared to be a natural Colombian emerald, but careful examination easily revealed its doublet nature, while Raman spectroscopy confirmed that both the top and bottom portions were indeed beryl.

	Microscopic observation revealed a very flat separation plane below the girdle, crossing the pavilion diagonally. Flattened gas bubbles were visible along the plane (figure 2, left), and a blue and orange flash effect was also apparent. Jagged three-phase inclusions typical of Colombian emeralds were visible in both parts, while fine growth tubes and fingerprints in helix patterns were seen only in the top portion. Inclusions did not cross the boundary between the two sections. Under long-wave UV light, the top showed a stronger red fluorescence than the bottom, with a distinct boundary between the two (figure 2, right). A whitish fluorescence was also observed along the plane. Illumination using crossed polarizers revealed that the top and bottom portions had different optical orientations, with two optic axes visible (figure 3). Typical of most emeralds, enhanced fractures showing a flash effect were found in both parts.

Figure 2. Left: Flattened gas bubbles are visible along the separation plane of the doublet. Field of view approximately 3 mm. Right: Viewed under long-wave UV light, the doublet displayed strong red fluorescence in the top portion but not the bottom. A distinct boundary between the two parts is clearly visible. Photos by Ahmadjan Abduriyim.

Figure 3. When the doublet was viewed under crossed polarizers, different optical orientations were apparent. At this angle, interference colors along the optic axis are clearly visible in the bottom portion but not the top. Photo by Claire Ito; field of view 11.60 mm.

	Immersion with methylene iodide revealed green angular zoning in the bottom, whereas the top had even, saturated green color. Both sections appeared to have enough green color to be considered emerald. The glue along the separation plane was colorless. This is unusual, as assembled imitations of emerald are often composed of pale beryl or other colorless materials with a green cement layer. We could only speculate on the circumstances leading to the creation of this unusual doublet. Source: GIA @topic:3


Title: Green Crystals in Yellow Sapphires Abstract: Figure 1. A bluish green spinel crystal found in a Sri Lankan yellow sapphire. Photomicrograph by Tyler Smith; field of view 1.76 mm.

Two yellow sapphires recently examined by the authors each contained a green crystal inclusion. Upon analysis, however, the two inclusions turned out to be very different minerals.

A yellow sapphire of Sri Lankan origin hosted a saturated bluish green crystal inclusion. Optically it was singly refractive, and Raman spectroscopy proved it to be a spinel crystal (figure 1). Spinel inclusions of this color have been documented in yellow sapphires before (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Vol. 1, ABC Edition, Zurich, 1986, pp. 353–354), but this crystal was remarkably large and completely enclosed in the stone.

Figure 2. A beautiful euhedral pargasite crystal displaying its monoclinic nature in yellow sapphire. Photomicrograph by Nathan Renfro; field of view 1.43 mm.
The second yellow sapphire contained a green semitransparent crystal that, unlike the previous inclusion, was doubly refractive and more rectangular in shape (figure 2), with sublinear striations and a smaller secondary crystal on the opposite side. With the aid of Raman spectroscopy, the brownish green crystal was identified as pargasite, a metamorphic calcium-dominated amphibole mineral associated with spinel and corundum deposits (J.W. Anthony et al., Handbook of Mineralogy, Vol. 2, Mineral Data Publishing, Tucson, Arizona, 1995). As an inclusion, pargasite has been previously documented in corundum—more frequently in rubies from Myanmar, Pakistan, and Tanzania, and in blue sapphires from Kashmir (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Vol. 3, Opinio Verlag, Basel, Switzerland, 2008). The fact that the host sapphire was yellow makes this inclusion a fascinating discovery for the authors. Source: GIA @topic:3


Title: Bismuth Glass-Filled Burmese Star Ruby Abstract: Figure 1. A 5.35 ct purplish red cabochon displaying asterism. Photo by Johnny Leung.

The Hong Kong laboratory recently examined a 5.35 ct purplish red oval cabochon displaying asterism (figure 1). Standard gemological tests yielded a spot refractive index (RI) of 1.76, medium red fluorescence under long-wave ultraviolet (UV) light, weak red fluorescence under short-wave UV, and a diagnostic spectrum in the handheld spectroscope, all of which were consistent with ruby.

Figure 2. Left: Blue flashes and trapped gas bubbles of various sizes and shapes along surface-reaching fractures and cavities. Photomicrograph by Xiaodan Jia; field of view 7.64 mm. Right: The bismuth glass-filled fractures and cavities were easily visible in the X-ray image. Image by Sze Ling Wong.
Magnification revealed iridescent silk and arrowhead-like inclusions similar to those frequently found in Burmese rubies. Apart from the natural inclusions, easily observable foreign substances for clarity enhancement were found along surface-reaching fractures and cavities. Numerous rounded to flattened gas bubbles and blue flashes were visible within filled fractures (figure 2, left). The filler also exhibited a different luster from that of the ruby under reflected light. X-ray radiography indicated heavy element depositions along these fractures and cavities (figure 2, right). The Fourier-transform infrared (FTIR) spectrum showed two broad absorptions centered at 3500 and 2670 cm–1 associated with manufactured glass. Qualitative analysis using energy-dispersive X-ray fluorescence (EDXRF) spectroscopy revealed the presence of bismuth, whereas no lead was detected. This confirmed that the foreign material was actually a bismuth-based glass.
Based on internal features and advanced testing results, the stone was positively identified as a manufactured product consisting of bismuth glass and ruby. Although bismuth-based glass has occasionally been applied to corundum as a filling material (Spring 2017 Lab Notes, p. 94), it is rare to detect it in star ruby. Source: GIA @topic:3


Title: “Red” Chrysoberyl versus Alexandrite: The Impact of Elevated Chromium Levels on Color and Color-Change Properties Abstract: K. Schmetzer, J. Hyrsl, H.-J. Bernhardt, and T. Hainschwang, “Purple to Reddish Purple Chrysoberyl from Brazil,” Journal of Gemmology, Vol. 34, No. 1, 2014, pp. 32–40. Photos courtesy of Karl Schmetzer.

              Gem-quality purple to reddish purple chrysoberyl, also known as “red” chrysoberyl, has been documented in Brazil. Red chrysoberyl has intense coloration and appears very dark violet-purple to purple in daylight and reddish purple to red-purple in incandescent light. Explaining the lack of green-blue coloration in daylight, in contrast to alexandrite, is a main focus of this paper.

Two samples displaying twinning, both from Brazil (one from Malacacheta, one without a specific locality), were investigated. Optical, micro-Raman spectroscopy, energy-dispersive X-ray fluorescence (EDXRF) spectroscopy, and electron microprobe techniques were used to characterize coloration, growth structures, inclusions, and trace-element chromophore distribution and amounts. The twinning present in both samples presented some difficulties in viewing color and pleochroism of the X, Y, and Z planes (parallel to the three crystallographic axes).As with alexandrite, the largest coloration difference exists in the Y plane. For this material, the color changed from yellowish orange in daylight to reddish orange in incandescent light, as opposed to alexandrite’s typically yellow-green to yellow-orange color change.

In characterizing quantitative data related to Cr and Fe, comparisons were made to data from “normal” Hematia and Malacacheta alexandrites. The reddish purple chrysoberyl was found to have higher Cr2O3 contents than “normal” Brazilian alexandrite from both localities. Alexandrite generally has Cr2O3 levels less than 1.0 % by weight and typically range from 0.4 to 0.7 wt.%, whereas the faceted reddish purple sample averaged 1.54 wt.% Cr2O3, with a wide 1.36–2.23 wt.% range. Furthermore, the faceted reddish purple chrysoberyl had an average iron content of 0.60 wt.% Fe2O3, comparable to “normal” samples from Malacacheta, but lower than average material from Hematita.

This elevation in Cr2O3 produces noticeably higher-intensity Cr3+ absorptions in the visible range that clearly diminishes how much transmission can occur in the absorption minimum around 490 nm in the blue-green region. Therefore, these crystals have a much less blue-green appearance in daylight than their more chromium-poor alexandrite relatives.

Much higher Cr2O3 levels have been documented in mostly nontransparent samples from other regions. A recently identified Cr analogue to chrysoberyl—Be(Cr,Al)2O4—contained 58 wt.% Cr2O3. This new mineral was named mariinskite after the Mariinsky mine, the largest emerald-alexandrite deposit in Russia’s Ural Mountains. Source: GIA @topic:2


Title: An Update on “Paraíba” Tourmaline from Brazil Abstract: Vivid blue, green, and purple-to-violet cuprian elbaites, renowned in the gem trade as “Paraíba” tourmalines, continue to be recovered in small amounts from northeastern Brazil. Since the initial discovery of this copper-bearing tourmaline in 1982, production has been sporadic and has not kept up with the strong market demand. Mining currently takes place at the original discovery—the Mina da Batalha—and at adjacent workings near São José da Batalha in Paraíba State. At least two pegmatite localities (the Mulungu and Alto dos Quintos mines) in neighboring Rio Grande do Norte State have produced limited quantities of cuprian elbaites. All of these pegmatites occur within Late Proterozoic metamorphic rocks of the Equador Formation; the source of the copper is unknown. Six blue to blue-green elbaites from Mulungu had lower copper contents (up to 0.69 wt. % CuO) than the brightly colored Mina da Batalha material reported in the literature. Source: GIA @topic:11


Title: Wollastonite Blizzard Within Glass Abstract: Figure 1. Faceted manufactured glass beads measuring approximately 8 mm in diameter. Photo by Robison McMurtry.

A collection of lovely faceted blue beads was presented to author EAS during an annual meeting of inclusion specialists at the 2017 Tucson shows. While most specimens of interest highlighted in these meetings are of extraordinary naturally occurring minerals and gem materials—some of which have appeared in this column—these rather ordinary beads were intriguing for the veritable blizzard of translucent colorless needles and short euhedral crystals that filled each one. They created a beautiful optical effect, especially when illuminated from below (figure 1). Upon acquisition, the original owner had been told these were Russian synthetic quartz, and indeed their age and azure color suggested such an origin. It came as a surprise when standard gemological testing (refractive index of 1.518, specific gravity of 2.47, and the absence of birefringence) identified the beads as glass, making the internal scene even more intriguing for its natural appearance. Raman spectroscopy at GIA’s Carlsbad laboratory identified the beads as manufactured glass, and the majority of the needles as the calcium silicate mineral wollastonite (figure 2). Additionally, relatively small blocky crystals scattered among the needles were conclusively identified as diopside (see Summer 2010 Lab Notes, p. 144).

Figure 2. Transmitted light reveals a blizzard of transparent wollastonite needles within the glass host, an indication of devitrification. Interspersed among the needles are blocky crystals of diopside. Photomicrograph by Nathan Renfro; field of view 2.03 mm.
Inclusions in glass such as wollastonite and diopside are indicators of devitrification, a process by which various components of the glass’s composition crystallize out when subjected to high temperatures and/or changes in temperature. The process varies according to the type of glass. This may also happen in natural glasses, as with obsidian, resulting in the attractive lapidary material known as snowflake obsidian, which sports white blooms of cristobalite crystals on a black background. Devitrified glass is also sometimes used to imitate natural gems, as seen in manufactured “meta-jade.” The beautiful blue inner world of these beads makes them a welcome addition to one’s library of inclusions. Source: GIA @topic:2


Title: A Microstructural Study of Pietersite from Namibia and China Abstract: Pietersite has been described as a brecciated variety of tiger’s-eye. This study examined pietersite specimens from Namibia and China (the main sources) using powder X-ray diffraction, optical microscopy, environmental scanning electron microscopy, and conventional gemological methods. On the basis of the results, quantitative approaches were developed to distinguish pietersite samples from the two localities. It is also proposed that the petrogenesis of this gem material is quite different from that of South African tiger’s-eye. Source: GIA @topic:1


Title: A New Method for Detecting Be Diffusion-Treated Sapphires: Laser-Induced Breakdown Spectroscopy (LIBS) Abstract: This article describes the first application of laser-induced breakdown spectroscopy (LIBS) to gemology. So far, the detection of Be-diffused sapphire and ruby has been based on LA-ICPMS or SIMS, neither of which is readily available to most laboratories. In this study, we use LIBS to detect beryllium in corundum at very low concentrations (down to ~2 ppm). This technique is a reliable tool for identifying Be diffusion–treated sapphires, and is affordable for most commercial gemological laboratories. As with other laser-based techniques, LIBS may cause slight damage to a gemstone, but this can be minimized by choosing appropriate instrument parameters. Source: GIA @topic:3


Title: Update on Diffusion-Treated Corundum: Red and Other Colors Abstract: Blue diffusion-treated sapphires have become a subject of considerable controversy since their introduction in significant quantities a few years ago. Now it appears that diffusion-treated corundum in additional colors, including red, may also be a commercial reality in the near future. At the request of the treater, the authors examined faceted specimens in a range of colors to document their gemological properties and determine identification criteria prior to any commercial release. Diagnostic features include unusually high refractive-index readings, atypical dichroism, atypical luminescence, patchy surface coloration, color concentrations along facet junctions, and spherical voids just below the surface. Source: GIA @topic:3


Title: Gemstone Carving in China: Winds of Change Abstract: The Chinese have labored to perfect the art of gemstone carving for several thousand years. Beginning with primitive tools and limited materials, they eventually developed the iron-tipped spindles and treadle machines that were to become the traditional tools of the trade for two millennia. With these relatively simple implements and meticulous craftsmanship, Chinese master carvers have produced some of the world's most sophisticated gemstone carvings. Within the past 10 years, however, increased governmental participation, the availability of power-driven machinery, and more varied carving materials have had a major impact on gemstone carving in China. Source: GIA @topic:10


Title: The Capão Topaz Deposit, Ouro Preto, Minas Gerais, Brazil Abstract: For over 200 years, the only known source of imperial topaz has been a small mining district near Ouro Preto. One of the oldest and most productive mines in the district is the Capão do Lana. This article examines the history of the Ouro Preto district as well as the geology of the area and occurrence of the topaz. Special attention is focused on the relatively sophisticated recovery methods used at the Capão do Lana mine. Also discussed is the gemology of this most prized color variety of topaz. Source: GIA @topic:1


Title: Bismuthinite Inclusions in Rose Quartz from Madagascar Abstract: Figure 12. These faceted samples of rose quartz (5.74 and 12.55 ct) from the Itongafeno pegmatite in central Madagascar contain conspicuous inclusions of bismuthinite. Photo by J. Hyrsl.

              Eye-visible inclusions are common in almost all quartz varieties except rose quartz. Although massive rose quartz is colored by submicroscopic inclusions (see J. S. Goreva et al., “Fibrous nanoinclusions in massive rose quartz: The origin of rose coloration,” American Mineralogist, Vol. 86, No. 4, 2001, pp. 466–472), only very rarely does this material contain macroscopic inclusions (see, e.g., Summer 2003 Gem News International, pp. 159–162). At the 2005 Tucson gem shows, one of these contributors (FD) had some unusual rose quartz from Madagascar that displayed abundant, conspicuous inclusions with a metallic luster (figure 12).

The material was recovered from the Itongafeno pegmatite (also known as Tsaramanga), located 23 km west of Antsirabe near the village of Mahaiza. This deposit is part of the Analalava pegmatite district and has been worked for asteriated rose quartz and dark blue aquamarine for almost 100 years. In addition to common pegmatite minerals, it has produced rare examples of emerald and native bismuth. Several vertically disposed zones of mineralization have been identified in the pegmatite, including rose quartz, smoky quartz adjacent to a thin Nb-Ta oxide and biotite layer, and rose quartz with metallic inclusions. About 60 kg of the included rose quartz was extracted between September 2003 and June 2004, although only a small percentage was suitable for cutting.

The inclusions in 10 faceted stones were examined, and with magnification they appeared metallic gray to black and had peculiar shapes (figure 13). They occurred in parallel rows of strongly elongated, sometimes striated crystals about 0.5 mm thick. Powder X-ray diffraction (XRD) analysis of an extracted crystal and chemical analyses of several surface-reaching inclusions in one sample with a Jeol 5800LV scanning electron microscope equipped with a Princeton Gamma-Tech energy-dispersive IMIX detector identified the inclusions as bismuthinite (Bi2S3). These were sometimes accompanied by smaller, more equant, yellow-to-black chalcopyrite grains. XRD also suggested the possible presence of a Cu-Bi-sulfosalt close to gladite in composition, which probably was present as thin metallic needles seen in some samples.

	Figure 13. The bismuthinite inclusions in the rose quartz from Madagascar appeared metallic gray to black, and showed a variety of irregular forms. A network of needle-like inclusions, possibly rutile, was responsible for the asterism in this rose quartz. Photomicrograph by J. Hyrsl; the field of view is approximately 3 mm.
In addition to the inclusions described above, the rose quartz also contained abundant tiny colorless needles possibly rutile; again, see figure 13) oriented in three directions at angles of 120°. These needles are apparently the cause of asterism in samples that are cut as spheres or cabochons.

To our knowledge, this is the first confirmed report of bismuthinite in faceted quartz from a pegmatite. Previously, bismuthinite was identified in quartz from tintungsten deposits and from Alpine-type fissures (see J. Hyrsl and G. Niedermayr, Magic World: Inclusions in Quartz, Bode Verlag, Haltern, Germany, 2003, p. 48). Source: GIA @topic:2


Title: Fordite from the Corvette Assembly Plant Abstract: Figure 1. Three fordite slag specimens alongside a partially open piece that shows paint layers with various colors and thicknesses. Photo courtesy of Jay’s Minerals.

	Gemstone cutter and mineral specimen collector Jason Baskin of Jay’s Minerals (Flemington, New Jersey) presented some spectacular freeform fordite cabochons, a byproduct of an automobile painting process that is long gone.

	Workers once painted automobile bodies on train cars, which are commonly used on large assembly lines. As the paint was sprayed onto the target, the overspray collected on the train cars, and the accumulated layers of excess paint went together with the painted car body to the oven. The factory removed the accumulation periodically to clean the working platform and possibly recycle the paint. Mr. Baskin was informed by his contact in the factory that it takes about 997 layers of paint to build a one-inch-thick fordite slag specimen (figure 1). Since hand spraying has been replaced by powder painting, fordite is no longer produced, and the material on the market is all that exists. Fordite was first collected at Ford Motor Company in Michigan in the 1940s. The material saved from the 1960s and 1970s has the boldest colors, since cars were painted in very bright colors during that period.

	Mr. Baskin was introduced to fordite about three years ago by a friend and fellow gem cutter whose uncle worked at the Corvette assembly plant in Bowling Green, Kentucky. Mr. Baskin and his friend now own a substantial collection of the material from that location. Mr. Baskin is also pursuing other sources, including Lincoln-Mercury paint from a Canadian plant and Ford paint from Detroit. He is also looking for fordite from Harley-Davidson motorcycles to fulfill the appetite of Harley lovers.

	The color layers and patterns of polished fordite are eye-catching, and experienced cutters know how to unveil its most beautiful side (figure 2). Because it is composed of paint, the material is very light. Protection such as a dust mask is necessary during the cutting and polishing processes.

Figure 2. Different patterns may be exposed when the fordite material is cut open. The original profile of the paint slag can be kept as well. Strata and concentric color circles are some of the most spectacular patterns. On the left is a 32.36 ct (52 × 64 mm) specimen; the one on the right is 41.86 ct (28 × 73 mm). Both pieces were polished by Jason Baskin. Photo by Robert Weldon/GIA; courtesy of the Clamshell.

	Mr. Baskin noted that jewelry designers and hobbyists purchase most of his fordite, though he also sells the cut material (figure 3) through other gem dealers. Some of the knobs from the heaters and gear shifters in the old Corvettes had a piece of embedded plastic; clients have him cut Corvette fordite to replace that plastic. Pricing ranges from $20 to several hundred dollars apiece. A very rare type of fordite from 1972 with large metal flakes sold for $400 once it was cut into a 40 × 30 mm cabochon.

Figure 3. The finished pieces shown here are some of the finest fordites on the market. Photo by Orasa Weldon/GIA; courtesy of Jay’s Minerals. Source: GIA @topic:1


Title: Amber Description Abstract: Rough amber sometimes contains assorted plant and insect inclusions. Many are even visible without magnification.

                      Amber is an organic gem. Organic gems are the products of living or once-living organisms and biological processes. Amber formed tens of millions of years ago, when sap from ancient trees hardened and fossilized.

	Amber comes in a variety of colors. The most familiar ones are yellow to orange, while a
	reddish color is rare. This group includes cloudy amber, reddish amber from Myanmar,
	amber with stress fractures, and pale, almost opaque, amber. - Alan Jobbins
Scientists and collectors treasure amber that contains suspended animal or plant fragments. These fossilized bits of once-living things were trapped in the hardening amber, creating a fascinating time capsule.

Some types of amber are found in the ground. Other types have been freed and carried by tides, ending up on beaches or near-shore areas. The Baltic coast bordering Germany, Poland, and Russia is still an important source of amber.

	Gas bubbles are very common amber inclusions. If there are a lot of them, they can give the material a cloudy appearance.
Amber is sometimes called “gold of the North.” Its warm luster is featured in beads, carvings, pendants, and cabochons, as well as decorative items like cups, bowls, snuff boxes, and umbrella handles.

A related material, called copal, is also fossilized tree resin, but it’s far younger than amber, at less than a million years old.

	Like amber, copal is fossilized tree resin, but it is not as old. Amber must be over a million years old, while copal is younger—often around a hundred thousand years old. Source: GIA @topic:12


Title: Report Check - 2213478946 Abstract: gia report number
2213478946

date of issue
Feb. 16, 2021

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LABORATORY-GROWN COLORED DIAMOND REPORT

Laboratory-Grown Colored Diamond Report

									            		REPORT DETAIL

									            		TREATMENT

									            		GROWTH METHOD

									            		COUNTRY OF ORIGIN

Laboratory-Grown Diamond Specification*

Shape and Cutting Style

Describes the shape and Cutting Style.

Cushion Brilliant

Measurements

Diamond dimensions listed as “minimum diameter – maximum diameter x depth” for round diamonds and “length x width x depth” for fancy-shaped diamonds.

7.04 x 6.41 x 4.40 mm

Carat Weight

Weight given in carats, recorded to the nearest hundredth of a carat. One carat is equal to 1/5 of a gram.

3.50 carat

Color

Includes a color description describing the hue as well as a fancy color grade describing the combined effect of tone and saturation. More generalized description is used for laboratory-grown diamonds.

Fancy Light Yellow

Color Distribution

Evenness or unevenness of color seen face-up using standard viewing procedures.

Even

Clarity

The relative absence of inclusions and blemishes.

VS2

PROPORTIONS

Depth

Table-to-culet depth, expressed as a percentage of average girdle diameter for round shapes or width for fancy shapes.

68.6%

Table

Table size expressed as a percentage of a round brilliant’s average girdle diameter for round shapes or width for fancy shapes.

62%

Girdle

Thickness of the intersection of the crown and pavilion which defines the perimeter of the diamond.

Slightly Thick to Thick, Faceted

Culet

Size of the facet at the tip of a gemstone relative to the average diameter for round shapes or width for fancy shapes.

None

FINISH

Polish

Smoothness of the diamond’s surface, assessed on a scale ranging from excellent to poor.

Excellent

Symmetry

Exactness of the diamond’s outline, and the shape, placement, and alignment of its facets, assessed on a scale ranging from excellent to poor.

Very Good

FLUORESCENCE

Fluorescence

Strength and color of the diamond when viewed under long-wave ultraviolet light. A fluorescence description of “none” represents a range of fluorescence from indiscernible to very faint. Used for identification purposes.

Medium Blue

CLARITY CHARACTERISTICS

Clarity Characteristics

List of the most significant clarity characteristics present in the diamond that justifies the clarity grade; a maximum of four characteristics are listed.

Growth Remnant, Growth Remnant, Indented Crystal Surface, Growth Remnant

Key to symbols
Growth RemnantGrowth RemnantIndented Crystal SurfaceGrowth Remnant

COMMENTS

Comments

Additional growth remnants are not shown.
This is a man-made diamond produced by CVD (Chemical Vapor Deposition) growth process and has evidence of post-growth treatments to change the color.

INSCRIPTION(S)

Inscription(s)

GIA 2213478946, LABORATORY-GROWN

*This GIA Laboratory-Grown Diamond Report describes color and clarity specifications on the same scale as the GIA Diamond Grading Report for natural diamonds. The specifications do not correlate to nature’s continuum of rarity. To learn more about laboratory-grown diamonds, including how GIA differentiates them from natural diamonds visit GIA.edu/GIALGDR

Feb. 16, 2021

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GIA LGDR results will only be provided via Report Check. All Report Check information is subject to these limitations.

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Learn More About Colored Diamonds

	Explore colored diamonds history, research, quality factors, and more in the GIA Gem Encyclopedia.

Learn More Source: GIA @topic:7


Title: Spinel Inclusion in Spinel Abstract: Figure 1. This 26.73 ct dark pink-purple spinel contained a spinel crystal inclusion. Photo by Robison McMurtry.

A 26.73 ct transparent dark pink-purple oval mixed cut (figure 1) was submitted to the Carlsbad laboratory for identification services. Standard gemological testing showed a refractive index of 1.719 and a hydrostatic specific gravity of 3.59. The stone fluoresced very weak red to long-wave UV light and was inert to short-wave UV. Observed using a handheld spectroscope, the stone showed thin absorption bands near 680 nm, with fine absorption lines near 670 nm. These gemological properties were consistent with spinel.

Figure 2. Under diffused lighting, the outline of the spinel crystal was only partially visible. Photomicrograph by Ziyin Sun; image width 3.70 mm.
Interestingly, microscopic examination showed that the spinel was relatively free of inclusions except for a very low-relief solid inclusion that was only partially visible (figure 2). Examination with polarized light (figure 3) revealed the entire outline of the low-relief crystal. Unaltered crystals generally provide strong evidence that a stone has not been heated, and this inclusion showed no alteration. But it is also important to consider the identity of certain inclusions when using them as an indication for thermal treatment. Due to the low relief of this inclusion, it is very likely a spinel inside of spinel. Their matching refractive index explains why the inclusion is nearly invisible. Since the host and inclusion are the same material, we would not expect to see any alteration due to heat treatment. Therefore, the unaltered appearance of this inclusion cannot be used to determine that this spinel has not been heat treated.

Figure 3. Under polarized lighting, the outline of the spinel crystal was clearly visible. Photomicrograph by Ziyin Sun; image width 3.70 mm.
The spinel’s visible absorption spectrum revealed that its purple color results from the combination of Fe and Cr (figure 4). Absorption bands with a maximum at 400 and 550 nm are caused by Cr3+ (D.L. Wood et al., “Optical spectrum of Cr3+ ions in spinels,” The Journal of Chemical Physics, Vol. 48, No. 11, 1968, pp. 5255–5262). Fe2+ causes the absorption band from 400 to 590 nm, while the Fe2+/Fe3+ charge transfer and Fe2+ cause the absorption bands from 590 to 700 nm (S. Muhlmeister et al., “Flux-grown synthetic red and blue spinels from Russia,” Summer 1993 G&G, pp. 81–98).

Figure 4. The spinel’s visible spectrum revealed that its dark pink-purple color was caused by Cr and Fe.
Spinels submitted to GIA’s laboratory are routinely checked using advanced analytical tools. Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) was used to confirm the natural trace elements. Higher concentrations of Li (27.7 ppmw), Be (87.4 ppmw), Zn (133 ppmw), and Ga (63 ppmw) indicate a natural origin, and the specimen’s photoluminescence (PL) spectrum was consistent with a heated spinel due to the broad full width at half maximum (FWHM) observed at 687.5 nm (figure 5; see S. Saeseaw et al., “Distinguishing heated spinels from unheated natural spinels and from synthetic spinels,” GIA Research News, April 2009, http://www.gia.edu/gia-news-research-NR32209A). It was unusual to see a spinel with this dark pink-purple color showing evidence of heat, as we typically see only red spinels that have been heated. From careful microscopic examination and advanced gemological testing, we were able to conclude that this was a natural spinel showing indications of heating.

Figure 5. The gray spectrum of unheated spinel shows that the FWHM (full width at half maximum) of the peak with highest counts is 0.92 nm and the position of the peak is at 685.5 nm. The purple spectrum, representing the dark pink-purple spinel, shows that the FWHM of the peak with highest counts is 6.11 nm and the peak is shifted from 685.5 to 687.5 nm. Source: GIA @topic:3


Title: Flux-Grown Synthetic Ruby with Hydrothermal Synthetic Seed Crystal Abstract: Figure 1. The zigzag-like growth structure observed in this 1.18 ct synthetic ruby is characteristic of hydrothermal growth. Photomicrograph by Nathan Renfro; field of view 1.42 mm.

              The Carlsbad laboratory recently received a 1.18 ct transparent red octagonal step-cut stone for ruby report service. Standard gemological testing established the following properties: RI—1.762 to 1.770; birefringence—0.008; optic sign—uniaxial negative; pleochroism—orangy red to purplish red; specific gravity—4.01; fluorescence reaction—strong red to long-wave, weak red to short-wave UV radiation. Examination with a desk-model spectroscope revealed a typical ruby spectrum. All of these properties were consistent with natural or synthetic ruby.

Under magnification, the most distinctive internal characteristic in the crown was the presence of strong irregular growth features: zigzag- or mosaic-like striated patterns (figure 1), typical of a hydrothermal synthetic. Other areas of the ruby lacking these irregular growth features contained hexagonal metallic platelets and high-relief, whitish flux inclusions (figure 2), typical of a flux-grown synthetic. Flux and hydrothermal inclusions have not been previously documented in the same specimen.

	Figure 2. When the synthetic ruby was examined under diffused fiber-optic lighting and darkfield illumination, hexagonal platinum platelets and trapped flux residue became apparent. Photomicrograph by Nathan Renfro; field of view 1.42 mm.
Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) analysis revealed traces of Ca, Ti, Cr, Fe, Mo, Rh, Sn, W, and Pt. The low amount of Fe and Ti, the absence of V and Ga, and the presence of Pt were consistent with flux-grown corundum.

Both natural and flame-fusion synthetic ruby have been used as seed crystals in the flux growth of ruby (J.I. Koivula, “Induced fingerprints,” Winter 1983 G&G, pp. 220–227; Summer 1991 Lab Notes, p. 112). The seed crystals are generally removed during the cutting process but may, on rare occasions, be detected in finished specimens. Upon close microscopic examination, we noted that several of the flux-filled healed fractures (wispy veils) extended into the areas showing hydrothermal graining. These observations led us to conclude that the hydrothermal material was a seed crystal and that the flux healing was a secondary process to the hydrothermal growth. There was an irregular separation between the materials under brightfield illumination.

This unusual combination of a hydrothermal ruby seed with flux ruby overgrowth is the first of its kind examined by GIA. Source: GIA @topic:3


Title: Shrinkage Cracks in Fire Agate Abstract: This fire agate from Mexico displays an interesting weblike network of shrinkage cracks that were likely the result of desiccation during formation. Photomicrograph by Nathan Renfro; field of view 4.11 mm.
Over the last few years, the author has encountered numerous examples of fire agate (a variety of quartz chalcedony) displaying a random weblike pattern, including a parcel of cabochons from Mexico purchased at the 2023 Tucson gem shows. Fire agates typically show a botryoidal structure reminiscent of a cluster of grapes, so this unusual pattern was quite noteworthy.
Microscopic examination of the cabochons revealed that the pattern was most likely the result of shrinkage cracks caused by desiccation. This drying out created a volume reduction that pulled apart the silica material during formation of the fire agate, producing a pattern of irregular separations that were later infilled by a secondary generation of chalcedony, which then preserved the pattern (see above). These shrinkage cracks stand out in high contrast to the host chalcedony as interruptions in the iridescent phenomenon that result from broken layers of goethite where shrinkage occurred. While not particularly common, shrinkage cracks in fire agate create a unique pattern in this colorful gem material. Source: GIA @topic:2


Title: Unusual Purple Fluid in Quartz Abstract: Figure 1. This 27.76 ct pear-shaped double cabochon contained several fluid inclusions with a vibrant purple component. Photo by Annie Haynes; courtesy of Mike Bowers.
Recently the authors examined a 28.93 mm long, 27.76 ct transparent pear-shaped double cabochon rock crystal quartz that contained numerous fluid-filled negative crystals (figure 1). Oddly, some of the negative crystals also hosted a brightly colored purple liquid in addition to what appeared to be a colorless liquid, the two liquid phases being immiscible (figure 2).

Figure 2. Several fluid-filled negative crystals were present in this rock crystal quartz cabochon, a few of which contained a highly unusual brightly colored purple liquid. Photomicrograph by Nathan Renfro; field of view 14.50 mm. Courtesy of Mike Bowers.
Not all of the fluid inclusions within this quartz contained the purple component. However, all of the purple liquid–hosting negative crystals did contain partially healed, limonite-stained fractures intersecting them. This suggests that the purple fluid may have entered the negative crystal cavities through a post-growth or secondary process rather than homogeneous entrapment during growth.
While colored fluid inclusions have been previously reported in quartz—colors that include blue, yellow, and orange (see e.g., Spring 2004 Gem News International, pp. 79–81; Spring 2006 Gem News International, p. 71)—this is the authors’ first observation of a purple fluid trapped within quartz. Unfortunately, Raman spectroscopy to identify the fluid was unsuccessful, as the fluid was too deep in the crystal. While the composition of the fluid is unknown, as well as the conditions under which the fluid entered the quartz, there is no obvious indication that it resulted from an artificial process. However, the possibility of such artificial tampering cannot be ruled out entirely. This fascinating purple fluid inclusion is one of the strangest and most interesting the authors have examined. Source: GIA @topic:2


Title: Blue Inclusion in Rock Crystal Quartz Abstract: Figure 1. This 118.16 ct polished modified cube of rock crystal quartz contains an interesting tuft of blue needles, which may be tourmaline. Photo by Robert Weldon; courtesy of Mike Bowers.

Figure 2. This tuft of blue needles has nucleated on a quartz crystal and tapers toward the end opposite the core quartz crystal. Although too deep to be identified by Raman spectroscopy, the needles resemble light blue needles of tourmaline. Photomicrograph by Nathan Renfro; field of view 10.07 mm. Courtesy of Mike Bowers.
An interesting tuft of light blue needles was recently observed in a polished modified cube of rock crystal quartz (figure 1). The needles nucleated on a nearly invisible quartz crystal with the tuft tapering toward the opposite end (figure 2). When the tuft was examined looking parallel to the optic axis of the host quartz using cross-polarized light, the small included quartz crystal surrounded by the blue needles stood out in high relief due to the crystallographic misalignment with the host quartz. It was also interesting to note that the included quartz was perched at the apex of a twinned sector of the host quartz (figure 3). While the needles were located too deep within the quartz to conclusively identify with Raman spectroscopy, their appearance (in the author’s experience) suggests they may be pale blue tourmaline. This beautiful inclusion in rock crystal quartz is a striking example of a microfeature in a gem cut to showcase an inclusion.

Figure 3. When the host quartz is examined looking parallel to the optic axis, the core quartz crystal stands out in high relief and is interestingly located at the apex of a twinned sector of the host. Photomicrograph by Nathan Renfro; field of view 9.32 mm. Courtesy of Mike Bowers. Source: GIA @topic:3


Title: Greenish Blue Spodumene Abstract: Figure 1. This 40.50 ct greenish blue specimen was identified as irradiated spodumene. Photo by Gagan Choudhary.

Green and yellow colors of spodumene, in addition to the widely known violet-pink variety kunzite, are now familiar to the trade and often submitted to gem labs. Recently, this contributor examined a greenish blue stone (figure 1) that unexpectedly turned out to be spodumene.
The 40.50 ct oval mixed-cut specimen measured 24.50 × 10.60 × 10.42 mm. It appeared quite dull, with areas of extinction caused by gray overtones and improper fashioning. The face-up color was heavily influenced by the two pleochroic colors, green and blue. The specimen’s overall appearance was similar to tourmaline, though gemological examination ruled out that possibility. The following gemological properties were recorded: optic figure—biaxial; RI—1.660–1.675; birefringence—0.015; hydrostatic SG—3.19; fluorescence—inert; and weak absorption bands in the blue, green, and yellow-orange regions at around 440, 545, and 600–650 nm in the desk-model spectroscope. The RI and SG values are consistent with those reported for spodumene in the gemological literature. Magnification revealed a few long, conical growth tubes below the table facet and cleavage planes along the girdle edge—inclusions typical for spodumene. The most striking feature of the specimen was its strong pleochroism (figure 2), which displayed three colors: green, blue, and violet. Infrared and Raman spectroscopy further confirmed the sample as spodumene. EDXRF analysis revealed the presence of Al, Si, Fe, and Mn, with a higher amount of Fe than Mn. Polarized UV-visible-NIR spectroscopy in the 200–800 nm region (figure 3) revealed a difference in absorption patterns. The violet and green directions displayed small peaks at ~430 and 437 nm, and absorption bands in the region 500–700 nm. The violet direction showed broad features at ~545 and 630 nm, the green direction at ~545, 605, and 655 nm. The feature at ~437 nm has been assigned to Fe3+ (R. Lu, “Color origin of lavender jadeite: An alternative approach,” Winter 2012 G&G, pp. 273–278). The feature at ~430 nm has been assigned to Mn2+ and those in the 500–700 nm region to various states of Mn (Mn3+/Mn4+) and its sites in the structure (see I. Petrov, “Role of natural radiation in tourmaline coloration: Discussion,” American Mineralogist, Vol. 75, 1990, pp. 237–239). The peak at ~630 nm indicates a defect usually produced by irradiation (E.W. Claffy, “Composition, tenebrescence and luminescence of spodumene minerals,” www.minsocam.org/ammin/AM38/AM38_919.pdf). These samples were irradiated via X-ray.

Figure 2. The artificially irradiated greenish blue spodumene displayed strong pleochroism, exhibiting three colors: blue (left), violet (center), and green (right). Photos by Gagan Choudhary.

Figure 3. Polarized UV-Vis-NIR spectra of the greenish blue spodumene display bands related to Fe3+, Mn2+, Mn3+, and Mn4+. The band at ~630 nm is related to an irradiation-produced defect.
It is widely known that green spodumene without chromium as the chromophore often results from irradiation, but this contributor had never observed a greenish blue color in spodumene. Irradiated green spodumene typically displays a strong blue pleochroic color along the c-axis. In this case, the c-axis was not determined, but one direction displayed a strong blue color, which was further supported by the peak at ~630 nm. Source: GIA @topic:3


Title: Perettiite-(Y) and Tusionite Inclusions in Phenakite from Myanmar Abstract: Figure 1. Left: Perettiite-(Y) bundle in phenakite from Khetchel, Myanmar; image width 3.8 mm. Right: Tusionite plates in phenakite from Khetchel; image width 2.5 mm. Photomicrographs by P. Škácha.
Every year about 100 new minerals are described, but few have been discovered as inclusions in gemstones (e.g., carmichaelite in chrome pyrope from Arizona and protoenstatite in labradorite from Oregon). In 2015, a new mineral—perettiite-(Y)—was described as inclusions in phenakite crystals from pegmatites by Khetchel village in the Molo area near Momeik, about 100 km northeast of Mogok (R.M. Danisi et al., “Perettiite-(Y), Y3+2Mn2+4Fe2+[Si2B8O24], a new mineral from Momeik, Myanmar,” European Journal of Mineralogy, Vol. 27, No. 6, pp. 793–803). It was named after Swiss gemologist Adolf Peretti, head of the GemResearch Swisslab, who found the first specimens.
Perettiite-(Y) has a very unusual composition, Y2Mn4Fe[Si2B8O24]. It forms strongly tapered yellow needles up to several millimeters long; only very rarely do they form beautiful bundles (figure 1, left). Several other inclusions were also found in phenakite from the same locality, including the very rare tin borate tusionite, which forms groups of mica-like yellow plates (figure 1, right). Phenakite itself is also unusual, because it often forms twins with very strange “drill bit” termination (figure 2). Unfortunately, perettiite-(Y) and tusionite inclusions (figure 3) are extremely rare, found in just a few pieces in a thousand phenakite crystals, so cut stones will remain a valuable collector’s rarity (figure 3).

Figure 2. Phenakite twin, measuring 1.35 cm high, with a “drill bit” termination and perettiite-(Y) inclusions. Photo by J. Hyršl. From the author’s collection.

Figure 3. Phenakite with tusionite (left) and perettiite-(Y) inclusions (right). The specimen on the left weighs 1.77 ct, and the one on the right weighs 2.31 ct. Photo by J. Hyršl. From the author’s collection. Source: GIA @topic:2


Title: Bicolor Double-Eye Tourmaline Abstract: Figure 1. Fashioned as a double cabochon and weighing 6.39 ct, this bicolor tourmaline from Newry, Maine, displays pink and white chatoyant bands on opposite sides. One side of this tourmaline is pink (left), while the reverse side is colorless (right). Even though the chatoyancy-causing growth tubes are only in the colorless portion, both sides exhibit a sharp cat’s eye. Photos by Kevin Schumacher.

              The Summer 2009 G&G Lab Notes section (pp. 139–140) described a 5.44 ct tourmaline double cabochon that displayed a sharp, silvery white chatoyant band on one side and a deep golden brownish yellow eye on the reverse side. Microscopic examination revealed that this phenomenal optical effect was due to a combination of pronounced color zoning and growth tubes that were in precise crystallographic alignment.

This same phenomenon was observed in a double cabochon cat’s-eye tourmaline cut from rough discovered at the well-known pegmatite complex in Newry, Maine. This cushion-shaped cabochon, weighing 6.39 ct and measuring 11.31 × 11.12 × 6.39 mm, was pink on one side and essentially colorless to white on the opposite side. Consequently, its chatoyant bands had clearly different colors, one pink and the other a silvery white (figure 1).

As expected of a cat’s-eye gem, when two incident light sources (fiber-optic wands) were positioned side by side above this tourmaline, two separate eyes became visible. As the gem was rotated under and between the light beams, these eyes appeared to converge, closing to form a single chatoyant band and then opening, like a winking eye. This interactive phenomenon was visible on both sides of the double cabochon.

As with the previously reported example, microscopic examination revealed very strong color zoning, with a pink layer positioned parallel to a zone of near-colorless tourmaline, also known as achroite. The gem was fashioned so that the color layers were divided parallel to the girdle plane. The achroite layer appeared silvery white because of numerous parallel reflective growth tubes uniformly distributed throughout it (figure 2), while no growth tubes were present in the transparent pink-colored zone. Reflection of light from these parallel tubes caused the silvery white eye observed on the colorless side of the cabochon. The opposite side owes its pink chatoyancy to reflection from those same tubes inhabiting the near-colorless zone as the light is transmitted back through the pink transparent layer of tourmaline.

Figure 2. Growth tubes oriented along the c-axis and present only in the colorless portion are responsible for the chatoyancy in this bicolor tourmaline, observed using fiber-optic illumination. Field of view 3.59 mm. Photomicrograph by Nathan Renfro.
This is the second time we have encountered a tourmaline displaying different colors of chatoyancy on opposite sides of a double cabochon. In order to enjoy both eyes, such a stone should be set as a pendant in a simple bezel with a swivel, allowing exposure of either the pink or the silvery white cat’s eye as desired. Source: GIA @topic:2


Title: Cuprite and Malachite in Agate from the Yanyuan Region, Sichuan Abstract: Figure 1. This 9.40 g gray-purple pendant was identified as agate. Photo by Su Xu.
The Yanyuan region in China’s Sichuan Province is rich in agates known for their vibrant colors, including pink, purple, and green. Dendritic inclusions are common in agates from many areas but rarely seen in agates from Yanyuan. Recently, our interest was drawn to a 9.40 g gray-purple carved pendant submitted for identification (figure 1) that displayed peculiar dendritic inclusions. The piece was reported by the client to be from Yanyuan.
Standard gemological testing of the pendant yielded a spot refractive index of 1.54, and Fourier-transform infrared (FTIR) spectroscopy was used to confirm the identity of the pendant. Microscopic observation revealed a blue-green spherical mineral surrounded by copper-red dendritic inclusions (figure 2), which appeared to have a metallic luster under reflected light.

Figure 2. Microscopic observation of the pendant revealed copper-red dendritic inclusions and a blue-green spherical inclusion. Photomicrograph by Su Xu; field of view 1.5 mm.
The red inclusions in the exposed surface and the blue-green inclusion nearby were analyzed with Raman spectroscopy. The analyses showed that the red inclusions were cuprite (Cu2O) and the blue-green sphere was malachite (Cu2(CO3)OH2), both of which were confirmed by energy-dispersive X-ray fluorescence (EDXRF) testing (figure 3). In the Raman spectra of the inclusions, the peak at 464 cm–1 was assigned to the agate host (figure 3).

Figure 3. Comparison between the Raman spectra obtained for the two kinds of inclusions found in the agate and reference spectra for cuprite and malachite from the RRUFF database. Spectra are offset for clarity.
While copper inclusions have been previously reported in purple chalcedony (Spring 2019 G&G Micro-World, p. 111) and chrysocolla chalcedony (M. Ye and A.H. Shen, “Gemmological and mineralogical characteristics of chrysocolla chalcedony from Taiwan, Indonesia and the USA, and their separation,” Journal of Gemmology, Vol. 37, No. 3, 2020, pp. 262–280), this is the first time we have identified two kinds of copper-bearing inclusions in agate from Yanyuan. Source: GIA @topic:11


Title: Zigzag Fingerprint in Sri Lankan Sapphire Abstract: The rectilinear zigzag-patterned fingerprint in this 3.21 ct blue sapphire shows beautiful vibrant colors, indicating a Sri Lankan origin. Photomicrograph by Yuxiao Li; field of view 4.45 mm.
The author recently examined a 3.21 ct oval mixed-cut blue sapphire. Chemical analysis and gemological observation of internal fissures suggested a Sri Lankan origin. Under fiber-optic illumination, the fingerprints showed rectilinear zigzag-patterned films with vibrant colors that resulted from thin-film interference (see above). The rectilinear structure of this fingerprint was caused by the natural healing process of a fracture oriented parallel to the c-axis.
These zigzag-patterned fingerprints often indicate a Sri Lankan origin, but they can also be found in sapphires from Myanmar and Madagascar. The undamaged rectilinear pattern could indicate that the stone is unheated. Source: GIA @topic:3


Title: Pink Sapphire with Graphite Inclusion Abstract: This pristine hexagonal platelet of graphite was seen in a pink sapphire from Sri Lanka. Photomicrograph by Jeffrey Hernandez; field of view 1.99 mm.
Graphite inclusions in corundum can occur as minute bodies inside negative crystals alongside trapped diaspore and carbon dioxide. They can also appear as separate large metallic-looking hexagonal plates or jumbled clusters of small flaky crystals. Graphite in sapphire commonly occurs in those from Sri Lanka or Batakundi, Pakistan (V. Pardieu et al., “Sapphires reportedly from Batakundi/Basil area,” GIA Research News, May 12, 2009). The author recently found a surprisingly well-formed hexagonal graphite platelet with surface etchings in a pink sapphire from Sri Lanka (see above). Taking into account the luster and structure of the inclusion in this particular stone, it was identified as graphite under the microscope.
Graphite is a stable form of layered carbon occurring as a submetallic opaque mineral with a black to steel-gray color range. It typically forms in carbon-rich metamorphic rock or in pegmatite. Formation of this inclusion is dependent on the grade of metamorphism and temperature in the growth environment. It is rare to find such a clean example of a singular graphite inclusion demonstrating the crystal system it belongs to. This graphite inclusion in pink sapphire was a remarkably pristine example of this inclusion and host relationship. Source: GIA @topic:3


Title: Fossilized Shell Consisting of Emerald Abstract: Figure 1. Eleven semitranslucent to opaque green and brown fossilized shells. Most of these specimens show clear shell outlines with green emerald grains. Photo by Johnny Leung.
Fossilized shells can be replaced by various types of gemstones, such as quartz and chalcedony (Spring 2014 Gem News International, p. 77), opal (A. Cody and D. Cody, The Opal Story: A Guidebook, Melbourne, 2008), and demantoid garnet (Winter 2013 Gem News International, pp. 257–258). In rare cases, emerald may also participate in the petrification of the shell and form pseudomorphs.
Recently, the Hong Kong laboratory received 11 fossilized shells composed primarily of emerald, measuring 13.00 × 8.20 × 6.16 mm to 24.54 × 16.72 × 12.57 mm and weighing 3.22 to 20.63 ct (figure 1). Most of them preserved the distinctive gastropod shell outlines, with different degrees of weathering.

Figure 2. Well-formed pyrite is a common accessory mineral associated with Colombian emerald. Photomicrograph by Johnny Leung; field of view 14 mm.
Under magnification, numerous small light green to green anhedral emerald crystals contained very fine fluid inclusions associated with well-formed brassy pyrite grains (figure 2), which is one of the most common mineral inclusions in Colombian emeralds (S. Saeseaw et al., “Geographic origin determination of emerald,” Winter 2019 G&G, pp. 614–646).

Figure 3. Clear shell structure and internal banding are shown in the X-ray radiograph (top left) of a fossilized shell measuring 22.06 × 14.85 × 10.32 mm and weighing 14.89 ct (top right). Scattered pyrite crystals (yellow in the colorized image on the bottom left) are deposited in a fossilized shell measuring 13.91 × 11.89 × 9.32 mm and weighing 5.07 ct (bottom right). Top images by Johnny Leung and Cheryl Wing Wai Au; bottom images by Ching Yin Sin and Emiko Yazawa.
An X-ray radiograph further revealed the spiral skeleton of the shell and scattered pyrite crystals (figure 3). The polycrystalline emerald was deposited evenly throughout the specimens, indicating complete replacement.
Fossilized gastropods were reported from the Matecaiia tunnel of the Gachala emerald mine in Colombia (P. Vuillet et al., “Les émeraudes de Gachalá, Colombie,” Le Regne Mineral, No. 46, July/August 2002, pp. 5–18). Gachala is not a principal emerald mining district but can produce high-quality material (D. Fortaleche et al., “The Colombian emerald industry: Winds of change,” Fall 2017 G&G, pp. 332–358). It is located on the Lower Cretaceous fossiliferous sedimentary rocks of the Eastern Cordillera Basin (B. Horton et al., “Construction of the Eastern Cordillera of Colombia: Insights from the sedimentary record,” in J. Gómez and D. Mateus-Zabala, Eds., The Geology of Colombia, Chapter 3, Vol. 3, 2020, Servicio Geológico Colombiano, Publicaciones Geológicas Especiales 37, pp. 67–88), where pyrite and emerald crystallized during the circulation of hydrothermal mineralizing fluids in black shales (G. Giuliani and L. Groat, “Geology of corundum and emerald gem deposits,” Winter 2019 G&G, pp. 464–489) and subsequently precipitated to form the fossilized shells. Source: GIA @topic:2


Title: Almandine in Graphite Schist Specimens Abstract: Figure 1. Jason Baskin is seen holding his largest almandine in graphite schist specimen at the 2014 Springfield Mineral Show. This specimen is now part of the collection of the Mineralogical and Geological Museum at Harvard University. Photo courtesy of Jay’s Minerals.

At this year’s Tucson shows, the authors saw the breathtaking almandine-pyrope in graphite schist specimens that debuted at the August 2014 East Coast Gem, Mineral, and Fossil Show in Springfield, Massachusetts (figure 1). Mine owner Jason Baskin (Jay’s Minerals, Flemington, New Jersey) first encountered the material from the Red Embers mine (then called the Two Fat Guys mine) in Franklin County, Massachusetts, in the early 2000s, and his family bought the mineral rights to this property in 2008. Mr. Baskin, along with his cousin Kyle Baskin and uncle Kevin Baskin, worked the mine (currently closed to the public) by hand, with tools such as chisels and hammers, for six years before unveiling these specimens and the location of the mine (figure 2).

Figure 2. Jason Baskin displays two giant pieces of graphite schist extracted from the
mine. Hand tools such as the sledgehammer behind him are used to mine the
specimens. Photo courtesy of Jay’s Minerals.
Good-quality almandine specimens are found in various localities in the eastern United States. This deposit is located in a metamorphosed zone full of layered graphite schist. According to Mr. Baskin, the thickness of the veins can vary from about 1 to 6 feet wide. Black columnar accompanying minerals can be found in the graphite matrix in between the garnet crystals on some specimens (figure 3). This long needle-like mineral was identified as dravite tourmaline. Based on his many years of mining experience at this location, Mr. Baskin says that the garnet crystals tend to have higher quality when they occur within a fold. Some of the garnet crystals are suitable for faceting, but it is the specimens that generate the most purchases. The largest crystal found to date is 28 mm in diameter; the largest faceted stone is 4.7 ct.

Figure 3. With a strong light source behind the specimen, the garnet crystals within the graphite glow, showing an attractive burgundy color. The black columnar mineral in the graphite matrix was identified as dravite. Not all specimens contain dravite, though its presence adds charm to the piece. Photo courtesy of Jay’s Minerals.
These striking specimens displayed sharp, dark red trapezohedra in fine-grained silvery graphitic schist (R.B. Cook, “Almandine New York City, New York County, New York State,” Rocks & Minerals, Vol. 84, No. 3, 2009, pp. 244–252). In a previously published article, Raman spectroscopy identified the garnet as predominantly almandine with some spessartine and minor pyrope components (C. Williams and B. Williams, “Almandine from Erving, Massachusetts,” Journal of Gemmology, Vol. 34, No. 4, 2014, pp. 286–287). Most specimens have multiple garnet crystals embedded in them, with the largest containing more than 100 crystals.

Due to the fine-grained nature of the host rock, a dust mask must be worn during the mining process. The most attractive aspect of these specimens is the exposure of the garnet crystals from both sides of the rock, which allows the light to travel through and make the garnet glow, showing its deep burgundy color (again, see figure 3). To achieve this goal, Baskin has tried numerous abrasives to remove the schist on both sides of the garnet without affecting the crystals’ surfaces. Some of the experimental abrasives included various kinds of glass beads, plastic beads, corn cobs, and even walnut shells. Finally, a special plastic made it possible to expose the garnets from both sides efficiently. The Mineralogical and Geological Museum at Harvard University, the American Museum of Natural History, Yale University, the University of Arizona, and Bill Larson of Pala International all currently own these specimens. Source: GIA @topic:1


Title: Artificial Glass Imitating Blue Amber Abstract: Figure 1. This 139.34 ct piece of artificial glass bore a striking similarity to blue amber. Photo by Lai Tai-An Gem Lab.

Artificial glass, a low-cost material, is capable of simulating any gemstone owing to its range of appearances (bodycolor, transparency, and phenomena). While this material is usually straightforward to identify, in some cases it is visually similar to the gem material being imitated. The Lai Tai-An Gem Laboratory recently received an object for identification that the client claimed was blue amber, but was subsequently determined to be artificial glass (figure 1).

Figure 2. Examination with a gemological microscope revealed gas bubbles. Photomicrograph by Lai Tai-An Gem Lab; field of view 2.6 mm.

Figure 3. Comparison of the infrared spectra for amber (red trace, collected by the author) and the artificial glass imitation (blue trace). The absorption at 1077 cm–1 is assigned to artificial glass.
The transparent, irregularly shaped, brownish yellow object with a bluish surface-related effect and vitreous luster weighed 139.34 ct and measured 37.0 × 33.2 × 28.6 mm. While it closely resembled amber, its heft was completely at odds with that expected for an amber of its size, providing the first important clue about its identity. Standard gemological testing revealed a spot refractive index of 1.50, a specific gravity of approximately 2.50 (amber’s is 1.08), a weak chalky blue reaction under short-wave ultraviolet radiation, and an inert response to long-wave UV. Inspection with a gemological microscope revealed gas bubbles (figure 2). Standard gemological testing confirmed that the item was not amber but artificial glass, though more advanced analysis was carried out. Fourier-transform infrared (FTIR) spectrometry was consistent with data we obtained on some samples of known glass (figure 3), confirming the identity. Energy-dispersive X-ray fluorescence (EDXRF) spectrometry also detected Si and Pb as the main chemical elements.
Blue amber’s optical effect, produced by the extremely shallow blue fluorescence stimulated by UV light, is strictly confined to the surface. A strong blue fluorescence under long-wave UV radiation is also typical in such amber, so the inert reaction also indicated the material's artificial nature. The object exhibited a similar optical effect when viewed at different angles or when the direction of illumination changed.
In our experience, it is uncommon to see this type of artificial glass imitating blue amber. The gas bubble inclusions, while typical of glass, may also be encountered in amber, so additional gemological analysis may be necessary to ensure the correct identification. This case clearly illustrates how artificial glass can imitate virtually every gemstone imaginable and mislead the unwary bargain hunter. Source: GIA @topic:3


Title: Blue-Green Pyrope-Spessartine Garnet with High Vanadium Abstract: Figure 1. Left: Twenty rough and two faceted garnets photographed under a light source with 6000K color temperature (a daylight-equivalent light simulator). Right: The same stones under a light source with 3100K color temperature (an incandescent light simulator). The 0.288 ct faceted stone measures 4.14 × 3.20 × 2.66 mm, while the 0.221 ct stone below it measures 4.01 × 3.09 × 2.10 mm. Photos by Kevin Schumacher.
A unique type of blue-green garnet has entered the market through New Era Gems (Grass Valley, California). The garnets reportedly come from a deposit near the border of Tanzania and Kenya. GIA’s Carlsbad laboratory obtained a small parcel of blue-green rough material and two faceted stones (figure 1, left) for examination. Unlike traditional blue-green garnets that exhibit a color change from purplish or orange red in incandescent light to bluish or yellowish green in daylight, these essentially remained blue in the lighting conditions we tested (CIE standard illuminants D65, A, F10, and F9, and a cool LED light with a 7500K color temperature). They showed only a weak color change from violet or blue in incandescent light (figure 1, right) to green or blue-green in daylight (again, see figure 1, left). We chose two samples from the New Era parcel, one with a classic violet to blue-green color change (garnet 1) and one piece of this new material with a weak color change from blue to blue-green (garnet 2). These were polished into wafers and analyzed to understand their chemical composition and color behavior.

Standard gemological testing revealed a refractive index of 1.760 to 1.765 and a hydrostatic specific gravity of 3.83 to 3.88. Fluorescence was inert to long- and short-wave UV light. No pleochroism was seen with the dichroscope. Using a handheld spectroscope, we observed absorption lines in the blue and violet section and a very broad absorption band centered around 590 nm wavelength. These properties are consistent with garnet.

Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) composition analyses were performed using a Thermo Fisher iCAP Q ICP-MS coupled with a New Wave Research UP-213 laser ablation unit. USGS reference glasses GSD-1G and GSE-1G were used as external standards and 29Si as the internal standard. The analyses were performed in the same region where the spectroscopic data was collected (table 1). The garnets were predominantly composed of equal amounts of pyrope and spessartine. The main difference was the higher concentration of V2O3 in garnet 2 (2.3 wt.%) than in garnet 1 (1.6 wt.%). Based on the classification system from Stockton and Manson (Winter 1985 G&G, pp. 205–218), the material represented by these two garnets is pyrope-spessartine. Vanadium and manganese are known to be the main cause of color change in pyrope-spessartine, yet garnet 2 contained a much higher vanadium component than any of the color-change pyrope-spessartine ranges (0.13–1.65 wt.% V2O3) reported by Schmetzer et al. (“Color-change garnets from Madagascar: Variation of chemical, spectroscopic and colorimetric properties,” Journal of Gemmology, Vol. 31, No. 5–8, 2009, pp. 258–259). To the authors’ knowledge, gem-quality garnet with this chemical composition has never been reported.

TABLE 1. LA-ICP-MS composition analyses of blue-green pyrope-spessartine garnet.

Sample name
Wafer 1 spot 1
Wafer 1 spot 2
Wafer 1 spot 3
Wafer 2 spot 1
Wafer 2 spot 2
Wafer 2 spot 3

Refractive index
1.760
1.765

wt.% oxide, converted from LA-ICP-MS

MgO
10.87
10.76
10.76
9.80
9.81
9.83

Al2O3
21.09
20.98
20.97
20.11
20.27
20.20

SiO2
38.93
39.44
39.43
38.52
38.81
38.69

CaO
5.74
5.76
5.78
6.21
6.07
6.17

V2O3
1.64
1.63
1.63
2.27
2.23
2.25

Cr2O3
0.29
0.29
0.30
0.37
0.38
0.41

MnO
19.60
19.33
19.33
20.55
20.32
20.39

FeO
1.58
1.55
1.55
1.61
1.60
1.58

Total
99.75
99.74
99.74
99.44
99.48
99.52

Number of ions on the basis of 12 oxygen

Mg
1.23
1.21
1.21
1.12
1.12
1.12

Fe2+
0.10
0.10
0.10
0.10
0.10
0.10

Mn
1.26
1.24
1.24
1.34
1.32
1.32

Ca
0.47
0.47
0.47
0.51
0.50
0.51

Total dodec.
3.06
3.02
3.02
3.07
3.04
3.05

V
0.10
0.10
0.10
0.14
0.14
0.14

Cr
0.02
0.02
0.02
0.02
0.02
0.02

Al
1.89
1.87
1.87
1.82
1.83
1.83

Total oct.
2.00
1.99
1.99
1.98
1.99
1.99

Si
2.96
2.99
2.99
2.96
2.97
2.97

Total tet.
2.96
2.99
2.99
2.96
2.97
2.97

mol.% end-members

Goldmanite
4.99%
4.99%
4.99%
7.04%
6.88%
6.95%

Uvarovite
0.87%
0.87%
0.90%
1.14%
1.15%
1.25%

Spessartine
41.22%
41.06%
41.03%
43.50%
43.38%
43.34%

Pyrope
40.23%
40.22%
40.19%
36.51%
36.85%
36.76%

Almandine
3.28%
3.24%
3.24%
3.37%
3.37%
3.32%

Grossular
9.41%
9.61%
9.65%
8.44%
8.38%
8.38%

Total
100.00%
100.00%
100.00%
100.00%
100.00%
100.00%

ppma of chromophore ions

Mn2+
62,900
62,000
62,000
66,700
65,800
66,100

Fe2+
5000
4890
4890
5170
5110
5060

Cr3+
868
869
891
1120
1140
1240

V3+
4990
4960
4960
6970
6830
6900

UV-Vis-NIR spectra were collected with a Hitachi U-2910 spectrometer with a 1 nm spectral resolution at a scan speed of 400 nm/min. The spectra were reflection-corrected using a method previously described by the authors (“Vanadium- and chromium-bearing pink pyrope garnet: Characterization and quantitative colorimetric analysis,” Winter 2015 G&G, pp. 348–369). The reflection-loss-corrected visible spectra were used to quantitatively calculate the material’s color at a wide range of path lengths and under different lighting conditions. Calculated color panels of the two garnets under incandescent light (CIE A illumination) and daylight-equivalent lighting (CIE D65 illumination) are shown in figure 2. The two garnets were also photographed under incandescent light (equivalent to CIE A) and fluorescent light (equivalent to CIE D65) for comparison. The close match between our photos and the calculated color panels confirmed the accuracy of our calculation. Figure 3 shows the possible color exhibited by two representative garnets with different path lengths (defined by the stone’s thickness) and the approximate corresponding carat weight of a well-proportioned round brilliant; for details of this calculation, see Sun et al. (2015). The high-vanadium garnet is bluer in incandescent light than the lower-vanadium garnet. Both become very dark at about 0.7 ct, which means the optimal color occurs in smaller sizes.

Figure 2. Top row: Photos of two garnets under incandescent light (A) and fluorescent light (daylight-equivalent light simulator D65). Bottom row: Calculated color panels under CIE A and CIE D65 illumination.

Figure 3. The color panels of two garnets under CIE A and CIE D65 illumination are quantitatively reproduced. The garnets’ colors are shown at different path lengths of light (defined by the thickness of the wafer) and carat weights. For each sample, the top and bottom rows represent the color under incandescent light (A) and daylight-equivalent light (D65), respectively.
To understand why the garnets stayed essentially blue in the lighting conditions tested, we can examine the visible absorption spectra. The calculated reflection-loss-corrected absorption spectra of garnets 1 and 2 at 5 mm path length are shown in figure 4. V3+ produces the large absorption band centered at about 585 nm. This band strongly absorbs orange and yellow light and a smaller portion of the red part of the visible spectrum. At low concentrations of vanadium, this absorption band produces two transmission windows, one in the blue part of the spectrum (figure 4, window A) and one in the red (figure 4, window B). This is the cause of the color change in low-vanadium pyrope-spessartine, as incandescent illumination highlights the red transmission window and daylight illumination highlights the blue-green window. As the concentration of vanadium increases, the red transmission window is preferentially closed and the color in both incandescent and daylight illumination is determined solely by the blue-green transmission window A. The concentration of V3+ relative to other chromophores (Mn2+, Fe2+, and Cr3+) is the fundamental reason why these higher-vanadium pyrope-spessartines remain blue under any lighting condition.

Figure 4. The calculated reflection-loss-corrected visible absorption spectra of garnets 1 and 2 with 5 mm path length; transmission window A is centered at 490 nm, while transmission window B is between 650 and 700 nm. Absorption bands at 410, 422, and 430 nm are caused by Mn2+, and a wide absorption band between 550 and 650 nm is caused mainly by V3+. Source: GIA @topic:2


Title: In Memoriam: Peter Keller Abstract: Dr. Peter Keller during his time as director of education at GIA. Photo by GIA.
Gems & Gemology mourns the passing of Dr. Peter Keller (see above) on November 8, 2022. Keller dedicated 50 years of his life to the gemological community and made countless contributions to GIA and G&G.
Born in 1947 in Allentown, Pennsylvania, Keller became interested in rocks and minerals at an early age. After obtaining his undergraduate degree in geology from George Washington University, Keller earned a master’s degree and a PhD in geology and earth science from the University of Texas. Keller began his career as curator of the Gem and Mineral Hall at the Natural History Museum of Los Angeles County before joining GIA as director of education in 1980.
For more than a decade, Keller was instrumental to G&G as an author and as associate editor. In the first half of the 1980s, he wrote several landmark articles documenting his visits to gem deposits worldwide. “Emeralds of Colombia” (Summer 1981) received third place in G&G’s annual Most Valuable Article awards. He was a key contributor to G&G’s Spring 1986 special issue on China, reporting on the emerging gem resources in various Chinese provinces.
In addition to writing for G&G, Keller wrote and published two influential books, Gemstones and Their Origins (1990) and Gemstones of East Africa (1992). He even ventured into filmmaking earlier in his career, serving as associate producer on a documentary film titled Gems of the Americas, which was coproduced by the Natural History Museum of Los Angeles County and GIA.
Keller spent much of his career as president and CEO of the Bowers Museum in Santa Ana, California. He is survived by his wife, children, stepchildren, and grandchildren. We extend our deepest condolences to his family, friends, and colleagues. Source: GIA @topic:7


Title: In Memoriam: Heitor Barbosa Abstract: Heitor Barbosa discovered Paraíba tourmaline in 1989 after almost a decade of mining. Photo by Duncan Pay.
The discoverer of Paraíba tourmaline, Heitor Barbosa (see above), died September 23, 2023, at the age of 90. Driven by intuition, Barbosa began his quest in the early 1980s at an old pegmatite mine in the Brazilian state of Paraíba. After several unsuccessful years and considerable skepticism from others, Barbosa prevailed and unearthed one of the world’s rarest gems—cuprian elbaite tourmaline—in 1989. Over the next two years, using simple hand tools and candles for lighting, Barbosa and his team recovered between 10 and 15 kg of the tourmaline characterized by its vivid blue and blue-green hues. Production slowed significantly in the years that followed, but Barbosa continued to work the mine, remaining hopeful that more tourmaline would be uncovered. Today, Barbosa’s son Sergio maintains the mine.
Barbosa is survived by his wife, four children, and two grandchildren. We extend our condolences to his family and friends. Source: GIA @topic:1


Title: Exsolved Particles with Natural Appearance Within Flux-Grown Pink Synthetic Sapphire Abstract: Figure 1. Left: Reflective platinum platelet with negative hexagonal growth within a flux-grown pink synthetic sapphire; field of view 2.34 mm. Right: Channels of exsolved interconnected flux; field of view 4.79 mm. Photomicrographs by Britni LeCroy.
The Carlsbad laboratory recently examined unusual exsolved flux particles in a flux-grown pink synthetic sapphire. The specimen, mounted in a ring, had an estimated weight of 13.07 ct and a refractive index of 1.760–1.770. It displayed a typical pink sapphire spectrum with a handheld spectroscope. Strong red fluorescence was seen under both long-wave and short-wave UV. Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) detected high levels of platinum; the concentrations of iron, beryllium, titanium, vanadium, and gallium were either below the detection or quantification limit.
Microscopic examination revealed further evidence of a synthetic origin: a single reflective platinum platelet with negative hexagonal growth through the center (figure 1, left). Also observed were interconnected channels of exsolved flux creating fingerprints (figure 1, right).

Figure 2. Fine rounded flux particles aligned into linear stringers resembling fingerprints and silk clouds seen within natural corundum. Photomicrograph by Britni LeCroy; field of view 1.73 mm.

A potentially challenging inclusion was seen in the form of minute rounded flux particles aligned in organized linear rows (figure 2), which displayed a striking resemblance to fingerprints and silk clouds commonly seen within natural corundum. These particles were observed in relative abundance at varying depths. Grid-like exsolved solid inclusions have been mentioned in the literature as possible properties of synthetic corundum (R.W. Hughes et al., Ruby & Sapphire: A Gemologist’s Guide, Lotus RWH Publishing, Bangkok, 2017). It has not been stated how abundant these natural-looking fingerprints are within flux-grown synthetic material, but this type of inclusion is rarely seen at the Carlsbad laboratory. Identifying the natural or synthetic origin of a stone with this type of natural-looking inclusion can be challenging. If a gem material is suspected of being synthetic, it is advisable to submit it to a gemological laboratory. Source: GIA @topic:3


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

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

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

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

An investigation of the literature and comparison to spectroscopic data of the authors’ samples showed that the synthetic reddish violet chrysoberyl crystals and faceted gems and the phenomenal alexandrite samples do appear to have Ti3+ as a chromophore, which leads to the unusual pleochroism observed. In the case of the reddish violet samples, Ti3+ seems to be the predominant chromophore, as only traces of chromium, iron, vanadium, and manganese were detected. The cat’s-eye and star alexandrite samples appear to have a combination of Ti3+ and Cr3+ chromophores (with additional rutile precipitates being responsible for chatoyancy and asterism). The transparent alexandrites, meanwhile, appear to have a combination of Cr3+ and V3+ as chromophores. The detection of trace levels of Ti3+ in chrysoberyl strongly suggests a synthetic origin and possibly further heat treatment in a reducing atmosphere (to form reddish violet samples with predominant Ti3+ contents), and in an oxidizing atmosphere (to form rutile precipitates). Source: GIA @topic:3


Title: Books: Imperial Jade of Burma and Mutton-Fat Jade of India Abstract: By S.K. Samuels, 248 pp., hardcover, publ. by SKS Enterprises, Inc., Tucson, AZ, 2014, $134.00.

              Jade is a subject that most in the Western world find hard to fathom, in no small part because much of the appreciation of this stone exists in Eastern writing. While Myanmar (Burma) has been the chief source of fine jadeite for more than two centuries, China’s history and close association with the material goes back thousands of years. As of the time of this writing (2014), the most expensive piece of jade ever sold at auction was not Burmese green jadeite from Myanmar, but white nephrite from western China. Perhaps this helps to illuminate just why the Western world considers jade to be "inscrutable."

Imperial Jade of Burma and Mutton-Fat Jade of India was written by Burmese native (and longtime U.S. resident) S.K. Samuels. There is much within its pages that will both thrill and enlighten the reader. I was particularly impressed by the author's wonderful accounts of Chinese nephrite brought to India for working by the subcontinent’s expert lapidaries during the Mughal Empire (1526–1857).

One of Samuels’s stated goals was to clarify the importance of Myanmar to the history of jade, while clearing up well-established inconsistencies. As an example, he cites the account of a British consular officer stationed in China named Mr. Warry, who visited Burma in 1888 with the first expedition of British troops. Warry not only spoke Chinese, his 7000-word essay gave a detailed description of jade in China, including the nephrite deposits in Xinjiang.  In this essay, Warry spends just 200 words relating a story told to him of the discovery of jade in Burma by a Chinese trader in the 13th century. Samuels dismisses this tale, but as evidence against it offers only vague statements by authors writing decades later, none of who had actually visited the Burmese jade mines. So whom does one believe, a China expert who visited the source and was presumably told of its discovery by someone at the site, or others who never visited the source? Samuels is free to disagree but he needs to build a better case than what is contained in this book.

In this text, Samuels repeatedly makes reference to the mistakes of other writers, but includes little in the way of quotations or citations to support his censure, and makes several unsubstantiated and inaccurate statements of his own. For instance, according to Samuels, by 2001, it was impossible for foreigners to visit either Mogok or Phakant; however, this reviewer visited both in 2004.

A full chapter is devoted to the gem material maw-sit-sit, but the name Eduard Gübelin does not appear at all. While this reviewer appreciates that maw-sit-sit had been mined for centuries and was mentioned by H.L. Chhibber in 1934, it was the Gübelin publications that put this material on the gemological map. Not to mention Gübelin’s impact is a significant omission in a book that claims to set the jade record straight.

Imperial Jade of Burma was privately published, but could have benefited greatly from a professional editor. Scholars (myself included) would welcome a comprehensive English-language volume on the history of Burmese jade, particularly one written by someone fluent in Burmese who could provide insights that only a native speaker might glean. Unfortunately, the current book falls short.

As an author myself, I appreciate the amount of work that goes into producing a book of this type. It is my sincere hope that the author will consider preparing a second, corrected edition. If done properly, it has the potential to become a valuable addition to the world gemological literature. Source: GIA @topic:12


Title: Pink Aventurine Quartz with Alurgite Inclusions Abstract: Figure 1. This bangle was submitted as “strawberry quartz” to TULAB. Photo by Shu-Hong Lin.
“Strawberry quartz” is not a strictly defined term in gemology but generally recognized in the market as single-crystal quartz with numerous striped or flaky hematite inclusions, which cause a pink to red overall appearance (D.I. Belakovskiy, “New acquisitions of the Fersman Mineralogical Museum, Russian Academy of Sciences (1997–2001),” New Data on Minerals, Vol. 38, 2003, pp. 101–112). Strawberry quartzes, due to limited mine production and rough sizes, are usually cut into beads, cabochons, or faceted stones or used for small carvings, all very popular products in the Taiwanese market.
Recently, a bangle was submitted for identification service to the Taiwan Union Lab of Gem Research (TULAB) as strawberry quartz (figure 1). The bangle had a brownish pink color in appearance and had a number of orangy pink to orangy red flaky crystals visible under the microscope. It had a refractive index of 1.54 and a specific gravity of 2.60. The material was found to be crystal aggregates through a polariscope and showed aventurescence under penlight.

Figure 2. Raman spectra comparisons between the red inclusions and those of quartz and muscovite from the RRUFF database identified the bangle as aventurine quartz with orangy red muscovite inclusions. The stacked spectra are baseline-corrected and normalized.
In order to identify this material and its inclusions, the bangle was analyzed with micro-Raman spectrometry and the RRUFF database. It was found that the material was actually polycrystalline quartz and the red flaky inclusions were muscovite (KAl2(Si3Al)O10(OH,F)2) (figure 2). SEM-EDS analysis of the inclusions exposed to the surface further verified them as iron-bearing muscovite; however, EDXRF analysis revealed trace amounts of manganese in addition to iron. In other words, this bangle should be defined as brownish pink aventurine quartz with pink to red muscovite inclusions.

Figure 3. Microscopic images of the red striped and irregular flaky hematite in strawberry quartz (left) and the orangy red muscovite (alurgite) inclusions in the pink aventurine quartz sample (right). Photomicrograph by Shu-Hong Lin; field of view 1.26 mm.
In comparison to those strawberry quartz with hematite inclusions, the red muscovite showed slight differences under the microscope. Hematite inclusions in strawberry quartz are usually striped, hexagonal, or irregular flaky crystals with medium to very dark red color under the microscope (figure 3, left); however, the red muscovite inclusions in the sample were mostly rounded flaky crystals with medium light to medium orangy red color (figure 3, right).

Figure 4. The visible light absorption spectrum of the pink aventurine quartz was compared to the reference spectra of mica (Mineral Spectroscopy Server of Caltech); results revealed that the visible light absorption spectra were consistent with that of alurgite. The overlapped spectra are normalized.
Moreover, the visible light absorption spectra of the bangle were analyzed and compared to those of mica on the Mineral Spectroscopy Server of Caltech. The pink aventurine quartz presented absorption peaks at 445, 454, 515, and 548 nm (figure 4), consistent with the spectrum of alurgite (GRR727, Mineral Spectroscopy Server of Caltech), which is a reddish purple variety of muscovite.
Since “strawberry quartz” is not a strictly defined marketing name, consumers should notice that there are actually different types of quartz with various inclusions sold with the same trade name. As an atypical strawberry quartz material, pink aventurine quartz with alurgite can be distinguished with hematite-included strawberry quartz through the methods of polariscope, microscope, and micro-Raman spectroscopy. Source: GIA @topic:2


Title: Analysis of Synthetic Ruby Overgrowth on Corundum Abstract: This photo shows one of the wafers prepared for LA-ICP-MS analysis in transmitted (left) and darkfield lighting (right). The thickness of the synthetic overgrowth and the inclusions in the natural seed are readily visible. Photos by J. Muyal © GIA.

                      This GIA laboratory study provides analysis of ten samples of synthetic ruby overgrowth on natural colorless sapphire “seeds.” One of the authors obtained them from a Bangkok-based gem dealer, who reported they resulted from chromium (Cr) diffusion experiments conducted in the 1990s by the Douros Company, a noted synthetic ruby grower. Those experiments sought to diffuse Cr into natural pink sapphire to provide a ruby color appearance.

The samples were purplish red to red in color and ranged from 1.40 to 2.17 ct.

GIA gemologists analyzed them using conventional microscopy, Fourier-transform infrared (FTIR) spectroscopy, and laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS).

Magnification revealed triangular growth marks, sub-parallel striations, and “heat wave”-like formations at the interface between the overgrowth and the seed. The overgrowth also contained numerous flux inclusions. Characteristics of the natural seeds included healed fractures, heat-altered crystals, and intersecting needles.

Three samples were fabricated into wafers for LA-ICP-MS analysis of their trace-element chemistry. For comparison purposes, the authors also collected chemistry data on representative synthetic ruby crystals: one flux-grown Douros and one hydrothermal example.

On the basis of microscope observation and for convenience, the authors divided the samples into two groups they dubbed “type I” and “type II.” Type I had no discernable boundary between the natural seed and the synthetic overgrowth, which was often confined to the table facet alone. Type II samples had much thicker synthetic overgrowth, with an obvious “dusty” interface between the two.

In the type I sample analyzed by LA-ICP-MS, the seed provided trace-element chemistry representative of natural corundum, while the synthetic overgrowth lacked elements such as vanadium, iron, and gallium, but had elevated levels of Cr, (up to 6,784 ppma), along with heavy elements atypical for natural corundum, including molybdenum, rhodium, and the heavy metal platinum.

The type II sample analyzed had even higher Cr levels in the synthetic overgrowth (up to 10,353 ppma), but unlike the type I example it also contained elements found in natural corundum, including magnesium, titanium, vanadium, iron, and gallium. However, manganese, nickel, zinc, and platinum were also present. This indicates different growth conditions from the type I example above. The natural seed had trace-element chemistry very similar to the type I sample described.

In both samples, the synthetic overgrowth did not correlate with the as-grown hydrothermal (Russian) and flux-grown (Douros) synthetic rubies included as a comparison.

The authors conclude with a caution not to be misled by the inclusions in the natural seed corundum, but to make a careful examination of the entire stone in order not to miss any characteristic flux inclusions within the synthetic overgrowth. Source: GIA @topic:3


Title: Opal from Querétaro, Mexico: Fluid Inclusion Study Abstract: The distinctive orange-to-red “fire" opals from Querétaro have not been found in significant quantities at any other locality. Through modern analytical methods, it has been determined that these opals formed at about 160ºC, from hydrous silica gels contained in fluids with small (up to 10%) variable amounts of  NaCl and CO2. These data, combined with geologic data, help explain the rare occurrence of this type of rhyolitic opal deposit. Source: GIA @topic:11


Title: Synthetic or Imitation? An Investigation of the Products of Kyocera Corporation That Show Play-Of-Color Abstract: The products of Kyocera Corp. that show play-of-color were investigated to determine if the materials are truly synthetic opal or rather are opal simulants. The authors propose that, because these materials contain no water, they do not match the composition of natural opals and, thus, should be designated opal simulants. The gemological properties of the samples examined are also provided, including those by which the Inamori material can be separated from natural opal. Source: GIA @topic:11


Title: The Hidden Beauty of Amber: New Light on an Old Subject Abstract: While many aspects of the nature of amber and its organic inclusions have been reported in the literature, virtually nothing has been recorded about the inorganic - mineral, liquid, and gas -inclusions "hidden" amid the better-documented life forms. This article takes a microscopic look at the gas bubbles and crystal forms that also belong to amber's inner world. With the use of polarized light, the author also documents strain centers in the amber, including movements made millions of years ago by animals trapped in the resin. Source: GIA @topic:12


Title: Characterization of the New Malossi Hydrothermal Synthetic Emerald Abstract: A new production of hydrothermal synthetic emeralds, grown in the Czech Republic with Italian technology, has been marketed since December 2004 with the trade name Malossi synthetic emerald. Several samples were investigated by standard gemological methods, combined with chemical analyses and UV-Vis-NIR and IR spectroscopy. A comparison of this material with natural and other synthetic emeralds (the latter grown by the flux and hydrothermal techniques) reveals that Malossi hydrothermal synthetic emerald can be identified on the basis of  microscopic features and chemical composition, along with the mid-infrared spectrum. Source: GIA @topic:3


Title: New Chromium- and Vanadium-Bearing Garnets from Tranoroa, Madagascar Abstract: Pyrope-spessartine garnets from Tranoroa, in southern Madagascar, contain appreciable Cr and somewhat lower V contents. Although these elements are responsible for the color-change behavior of similar garnets from the nearby Bekily area, the Tranoroa samples show only a slight change in color appearance from day or fluorescent light (brownish purple-red) to incandescent light (purplish red). Characteristic internal features in the Tranoroa garnets include networks of rutile needles and strain patterns caused by anomalous double refraction. Additional inclusions are graphite, quartz, negative crystals, apatite, zircon, and monazite. One Cr-bearing spessartine from the same area is also described. Source: GIA @topic:2


Title: Jeremejevite: A Gemological Update Abstract: The submission of a large (4.54 ct) jeremejevite of an unusual—yellow—color to the AGTA Gemological Testing Center prompted a search of the available gemological literature and a detailed examination of five additional samples to learn more about this rare gemstone. It was found that the information in some English-language texts was either confusing or contributed little to our gemological knowledge. The authors confirm the available standard gemological properties and add pertinent data for the UV-visible, infrared, and Raman spectra, as well as for trace elements measured by EDXRF. Source: GIA @topic:1


Title: Garnets from Madagascar with a Color Change of Blue-Green to Purple Abstract: Gemological, chemical, spectroscopic, and microscopic properties of blue-green color-change garnets from a new deposit near Bekily, Madagascar, are given. The samples are members of the pyrope-spessartine solid-solution series, with smaller constituents of almandine and grossular. The alexandrite-like color change from blue-green in daylight to purple in incandescent light is mainly caused by relatively high amounts of vanadium (about 1 wt. % V2O3). These garnets are particularly noteworthy because they represent the first commercially available “blue” garnets. Source: GIA @topic:2