# Publication Year: 2022
# Title: A Partially Hollow Natural Blister Pearl Filled with Foreign Materials
# Abstract: Figure 1. The 169.05 ct filled pearl, viewed from its face (left) and base (right). Note the indented feature on the base through which the filler material was inserted prior to plugging. Photos by Gaurav Bera.
Over the centuries, India has maintained its reputation as a natural pearl trading center. Since the launch of GIA’s pearl identification service in Mumbai in May 2022, the laboratory has received a variety of interesting items for identification. One that stood out owing to its size and internal structure was a unique partially hollow natural blister pearl with unidentified fillers (figure 1).

Figure 2. A: The pearl’s face showed minor surface blemishes; field of view 8.00 mm. B: The plugged area (boundary indicated by arrows) on the base with remnants of an adhesive around the oval opening; field of view 1.60 mm. C and D: Smoothed nacre layers provide evidence of heavy working and polishing on the base; field of view 3.00 mm. Photomicrographs by Nishka Vaz.
The very large baroque white pearl weighed 169.05 ct (33.81 g) and measured 43.12 × 28.83 × 19.26 mm. However, on initial examination, its “heft” (perceived weight compared to its actual weight in comparison to its size) felt heavier than it should have. While the pearl’s face-up side exhibited minor surface blemishes and good nacre condition (figure 2A), its base showed a deep oval indentation that looked a bit suspect to the unaided eye and needed further detailed examination. Under 40× magnification, the area revealed a distinct boundary with remnants of a transparent adhesive around it (figure 2B). Evidence of heavy working and polishing on and around the base was also clearly visible (figure 2, C and D).
Many loose nacreous baroque or semi-baroque pearls of this size are hollow to some degree, and most turn out to be blister pearls that were attached to the shell and removed at some point (“An unusual pearl,” GIA Research News, March 31, 2009) or were shell blisters. In order to ensure the durability of these hollow pearls, and sometimes to add weight and increase their perceived value, they are filled with various materials such as metals, resins, waxes, shell, and other pearls (Fall 2013 Lab Notes, pp. 172–173) and fashioned to improve their external appearance. Although the initial examination indicated that this pearl was likely filled with foreign materials, further analysis was required.

Figure 3. Opaque (white) areas indicate that metal pieces were placed within the pearl’s large internal cavity (left). Natural growth arcs and a small darker organic-rich area are visible at the pearl’s base (right). Images by Jayesh Surve.
Real-time microradiography revealed a large organic void/cavity filled with a radiopaque white material, probably small metal fragments or metal shavings (figure 3; see also Summer 2019 Lab Notes, pp. 251–254). Areas of greater radio-transparency suggested that some type of bonding or stabilizing material, possibly adhesive, may have been used to hold the foreign pieces in place, and there also appeared to be one other type of radiolucent material within the cavity. The pearl was examined in several directions in order to further analyze the internal structure and fillings. The outline of the void was smooth and blended with the external shape of the pearl. The outer nacre layers revealed fine growth arcs and a small organic-rich area was visible at the base, both of which aligned more with the growth features of a natural pearl. It was clear that this was originally a blister pearl or shell blister that had been cut from a shell, and that the indented area, which was the opening on the base of the pearl, was the point of attachment that was subsequently plugged. X-ray fluorescence proved that the pearl formed in a saltwater environment since most of its surface appeared inert and only a small area at the base displayed a very light greenish yellow reaction uncharacteristic of a freshwater environment.
Energy-dispersive X-ray fluorescence spectrometry on two areas (face and base) showed low or below detection levels of manganese and higher strontium levels, above 1000 ppm, both characteristic of a saltwater environment. The higher strontium levels coupled with the large size indicated that the mollusk from which the pearl originated was Pinctada maxima.
Raman analysis using a 514 nm laser excitation on two spots (face and base) of the surface produced high fluorescence due to the pearl’s light color and showed a doublet at 702 and 705 cm–1 as well as a peak at 1085 cm–1 indicative of aragonite. The photoluminescence spectra also displayed high fluorescence together with the aragonite peaks, as observed via Raman, typical of most nacreous pearls. Ultraviolet/visible/near-infrared spectra within the 220–850 nm range collected from the face and base were as expected for white to light cream-colored pearls and showed a predominantly high reflectance. The presence of a prominent 280 nm absorption feature coupled with moderate yellow reaction under long-wave UV excitation indicated that bleaching had most likely not been carried out.
After conducting a full analysis, GIA concluded that this sample most likely formed as a hollow natural blister pearl attached to its shell host. At some point, it was removed and the attachment area left an opening into the pearl. It was eventually worked and filled with foreign fillers (metal shavings/pieces and possibly some other materials) to improve its durability and make it suitable for setting; without the filling, it would not be usable in jewelry. The size, spectral characteristics, and chemistry were also consistent with a Pinctada maxima host mollusk. @chapter:54 @chapter:4 @chapter:54


# Publication Year: 2015
# Title: HPHT Synthetic Diamond Melee in High-Quality Jewelry Piece
# Abstract: Figure 1. A photo and a detailed illustration of the melee-set pendant show the location of all 118 samples. The single HPHT synthetic melee is highlighted in both images. Photo by Jian Xin (Jae) Liao.

Advances in the laboratory growth of diamonds have led to an increase in the number of synthetic diamonds seen at GIA. The existence of high-quality synthetic diamonds in melee sizes is of particular concern. This is due in part to the expense of examining melee relative to their value. While GIA can reliably identify synthetic melee, this requires individual analysis of each stone, preferably before mounting. In a complicated piece with hundreds of melee, this can be prohibitively expensive or time-consuming. The same is true for melee parcels. A synthetic diamond mixed into a packet may not be identified until later, deceiving dealers, jewelers, and consumers and potentially causing damage to the trade.

Recently, a pendant with 118 mounted stones was submitted to GIA’s New York laboratory for color origin analysis of each individual melee (figure 1). The pendant consisted of a central pear-shaped stone surrounded by three consecutive rows of round brilliant melee. Of the 118 stones, 58 were fancy yellow, including the center stone, and 60 were colorless. Using a Fourier-transform infrared (FTIR) microscope in reflection mode allowed detailed focusing of the infrared beam on the mounted stones, including those that were partially obscured. Analysis was carried out on a Thermo Nicolet iN10 FTIR microscope, which determined the diamond type classification of each melee stone from its mid-IR absorption spectra (C.M. Breeding and J. E. Shigley, “The ‘type’ classification system of diamonds and its importance in gemology,” Summer 2009 G&G, pp. 96–111). One melee was identified as an HPHT-grown (high-pressure, high-temperature) synthetic diamond, based on its infrared spectrum as well as its color, fluorescence pattern, and phosphorescence behavior. This 0.00431 ct melee was removed from the setting to confirm its origin as HPHT-synthetic. The rest were confirmed as natural diamonds.

Of the 118 melee, 114 were classified as type IaA or type IaAB. These were characterized by absorption from aggregated nitrogen centers, where A-centers (nitrogen pairs) and B-centers (four nitrogen atoms symmetrically surrounding a vacant lattice site) absorb infrared light at 1282 and 1174 cm–1, respectively. These spectra revealed sufficient A-center concentrations, eliminating the possibility of HPHT treatment, which would have deaggregated the centers into isolated nitrogen atoms (A.T. Collins, “The colour of diamond and how it may be changed,” Journal of Gemmology, Vol. 27, No. 6, 2001, pp. 341–359). Since A- and B-center absorptions occur solely in the infrared range, their presence does not produce color. Instead, the yellow color observed in 57 of these type IaA/IaAB stones resulted from absorption from the N3 defect at 415 nm (a complex of three nitrogen atoms surrounding a vacancy) and associated peaks at 453, 452, 465, and 478 nm. This spectrum is known as the “Cape series,” and such goods are commonly referred to as “Cape yellow.”

Two colorless stones were classified as type IaB, showing only pure B-aggregate absorption; the remaining colorless stone was type IIa, meaning it did not show IR absorption from any nitrogen-related impurities. Finally, a partially obscured yellow stone near the bottom of the piece was type Ib, showing absorption due to isolated nitrogen impurities, and characterized by features at 1130 and 1344 cm–1. Isolated nitrogen centers also produce a broad absorption feature in the UV-visible range (approximately 270 nm), resulting in a coloration often described as “Canary yellow.” Type Ib diamonds are very rare, representing only 0.1% of all natural diamonds (R. Tappert and M.C. Tappert, Diamonds in Nature, Springer, Berlin, 2011). Conversely, this diamond type is common in yellow synthetic diamonds. Due to the absence of A-centers, these four samples required further testing.

Photoluminescence spectroscopy confirmed that the type IaB and IIa stones were natural in origin. However, the type Ib stone (marked in figure 16) was further examined with DiamondView imaging, which showed that it exhibited strong yellow-green fluorescence under deep ultraviolet illumination (wavelength 230 nm) and indicated growth sector patterns typical of HPHT synthetic diamonds, as well as strong blue phosphorescence inconsistent with natural yellow type Ib diamonds (J.E. Shigley et al., “A chart for the separation of natural and synthetic diamonds,” Winter 1995 G&G, pp. 256–264; J.E. Shigley et al., “Gemological properties of near-colorless synthetic diamonds,” Spring 1997 G&G, pp. 42–53). The 0.00431 ct yellow stone was removed from its mounting for more comprehensive examination with the DiamondView (figure 2). Its cuboctahedral synthetic growth sectors were clearly seen from both the table and pavilion, confirming its HPHT synthetic origin.

Figure 2. Left and center: DiamondView fluorescence images of the 0.00431 carat type Ib diamond show clear cuboctahedral HPHT synthetic growth sectors. Right: The sample’s strong phosphorescence is atypical for a diamond of this type and color. Images by Martha Altobelli.
Although this could have been an isolated event, it underscores the need for caution when buying melee parcels or mounted pieces from unfamiliar sources. Nevertheless, it is important to note that such stones can be unequivocally identified as lab-grown. Colorless and near-colorless (D–N) unmounted diamonds larger than 0.01 ct can be tested using commercially available testing equipment such as the GIA DiamondCheck. Meanwhile, colored diamonds, smaller stones, and mounted jewelry need to be tested by a reputable gemological laboratory. Increased industry awareness, combined with diamond testing, may deter the spread of undisclosed synthetics, ultimately benefiting both sellers and buyers of polished diamond goods. @chapter:36 @chapter:1 @chapter:36


# Publication Year: 1983
# Title: Peridot from Tanzania
# Abstract: Peridot from a new locality, Tanzania, is described and compared with 13 other peridots from various localities in terms of color and chemical composition. The Tanzanian specimen is lower in iron content than all but the Norwegian peridots and is very similar to material from Zabargad, Egypt. A gem-quality enstatite that came from the same area in East Africa and with which Tanzanian peridot has been confused is also described. @chapter:51 @chapter:0 @chapter:51


# Publication Year: 2013
# Title: Orange Diamond with Unusual Color Origin
# Abstract: Figure 1. This 1.53 ct diamond was color graded as Fancy Intense pinkish orange. Spectroscopic analysis revealed it was type IIa and dominated by an approximately 550 nm band absorption, which usually introduces a pink-red color in natural diamonds rather than orange. Photo by Jian Xin (Jae) Liao.

              Orange bodycolor in diamond is usually caused by an absorption band centered at approximately 480 nm or by a high concentration of isolated nitrogen. Meanwhile, it is well known that the 550 nm absorption band often introduces pink to red colors. Physical models of these two optical centers have not been resolved yet. The New York laboratory recently examined an orange diamond whose color was attributed mainly to the 550 nm absorption band.

This 1.53 ct heart-shaped diamond (6.84 × 7.76 × 3.88 mm) was color graded as Fancy Intense pinkish orange (figure 1). Color was distributed evenly throughout the stone, which was very clean and showed no internal features under the microscope. The absorption spectrum in the infrared region revealed that it was a regular type IIa diamond, with no nitrogen-or hydrogen-related absorptions. The UV-Vis region showed a broad absorption band centered at ~550 nm and its corresponding band at ~390 nm, absorption features typical of natural type IIa pink diamonds. From the optical centers detected, we would not expect this diamond to show a dominant orange bodycolor.

The reason for this discrepancy is not fully understood. Our finding from this stone demonstrates the complexity of diamond color origin. @chapter:22 @chapter:1 @chapter:22


# Publication Year: 2022
# Title: Hyalite with Magnificent Internal Features
# Abstract: Figure 1. Purple fluorite cube, identified by micro-Raman spectroscopy, in a hyalite. Photomicrograph by U. Hennebois; field of view 1.2 mm.
The Laboratoire Français de Gemmologie (LFG) received for analysis a 1.83 ct hyalite, also known as opal-AN: an amorphous (A) opal containing hydrated silica molecules that are network forming (N) (E. Fritsch et al., “Green-luminescing hyalite opal from Mexico,” Journal of Gemmology, Vol. 34, No. 5, 2015, pp. 490–508). This is one of the rarest varieties of gem-quality opal. The gem fluoresced green under long-wave ultraviolet (365 nm) and, with more intensity, under short-wave UV (254 nm), due to U6+ in the form of uranyl (UO2)2+ (E. Gaillou et al., “Luminescence of gem opals: A review of intrinsic and extrinsic emission,” Australian Gemmologist, Vol. 24, No. 8, 2011, pp. 200–201). A purple fluorite (identified by a micro-Raman spectrometer; figure 1) and a series of cube-shaped cavities were visible (figure 2) in the hyalite, which appear to be all interconnected. Sometimes these cavities also contain small crystals of fluorite relics detected by Raman. Thus, these cavities may be the result of the partial dissolution of fluorite crystals. This would explain their cubic morphology, which cannot be explained by the dissolution of amorphous hyalite.

Figure 2. Interconnected cavities observed in a hyalite containing partially dissolved fluorite relics identified by Raman spectroscopy. Curved growth layers are also observed in the background. Photomicrograph by A. Delaunay; field of view 2 mm.
Between crossed polarizers, high-order interference colors were observed (figure 3), as expected for this gem. This is due to anomalous birefringence linked with the strain present between the curved growth layers of hyalite. Also, a fluid inclusion was observed in the intersection of the botryoids (again, see figure 3). This inclusion is composed mostly of gas, suggesting that this hyalite was deposited from a gaseous phase. Although some of these features have been previously observed in hyalite, it is rare to see them all in the same sample. To the best of our knowledge, this is the first reporting of pronounced cubic cavities in hyalite.

Figure 3. This fluid inclusion contains mostly a gaseous phase. It is trapped at the intersection of curved botryoidal growth zones and presents high-order interference colors obvious between crossed polarizers. Photomicrograph by U. Hennebois; field of view 1 mm. @chapter:15 @chapter:0 @chapter:15


# Publication Year: 2002
# Title: Winter 2002 G&G Book Reviews
# Abstract: “The Master Jewelers”
By A. Kenneth Snowman, Ed., 262 pp., illus., publ. by Thames & Hudson Inc., New York, 2002. US$29.95

“20th Century Jewelry: The Complete Source Book”
By John Peacock, 144 pp., illus., publ. by Thames & Hudson Inc., New York, 2002. US$34.95

“Louis Comfort Tiffany at Tiffany & Co.”
By John Loring, 255 pp., illus., publ. by Harry N. Abrams, New York, 2002. US$60.00

“The Love of Stones”
By Tobias Hill, 396 pp., publ. by Picador USA, New York, 2001, US$25.00

To view the full section, download the PDF above. @chapter:25 @chapter:2 @chapter:25


# Publication Year: 2019
# Title: “Rainbow Lattice” from Australia
# Abstract: These “rainbow lattice” specimens, a 4.14 g rough stone and a 2.18 ct kite-shaped cabochon, are from Harts Range in central Australia. Photo by Robert Weldon/GIA, courtesy of Rainbow Lattice.
One of the most striking materials encountered in the Riverpark Inn (Pueblo) Gem Show was “rainbow lattice.” This rare phenomenal gem is a variety of feldspar exhibiting aventurescence from exsolution hematite crystals and a rainbow lattice effect from oriented exsolution magnetite crystals. Supply is extremely limited, and the only source is the tiny Utnerrengatye mine in Harts Range, Northern Territory, Australia. Rainbow lattice was discovered in 1985 and acknowledged as a new gem material in 1989. One of the original discoverers, Darren Arthur, showed us all-new material he mined in 2018 and subsequently sorted and cut (see above). With its scarcity and unique appearance, rainbow lattice is a must for any serious rare gem collection. @chapter:1 @chapter:0 @chapter:1


# Publication Year: 2022
# Title: A Closer Look at Internal Etch Channels in Diamond
# Abstract: Figure 1. A 1.02 ct Fancy Deep brownish yellowish orange diamond with subsurface etch channels (upper right). Photo by Matthew Hardman.
The Carlsbad laboratory recently received a 1.02 ct cushion-cut Fancy Deep brownish yellowish orange diamond (figure 1). The yellowish color of this type Ib/IaA diamond is mainly attributed to single substitutional nitrogen atoms in the diamond lattice. In addition to the presence of multiple pinpoint inclusions, the diamond contained a bundle of internal etch channels extending from a single irregular-shaped opening on the girdle (figures 1 and 2).

Figure 2. A bundle of internal etch channels extending from a single opening on the girdle. Photomicrograph by Matthew Hardman; field of view 2.44 mm.

Figure 3. An irregular-shaped opening on the girdle where fluids/melts permeated through the diamond and formed the internal etch channels. Photomicrograph by Matthew Hardman; field of view 1.26 mm.
Narrow etch channels are rarely observed in gem diamonds. Etch channels can form due to dissolution of the diamond crystal by fluids/melts in the mantle, or during eruption to the surface (T. Lu et al., “Observation of etch channels in several natural diamonds,” Diamond and Related Materials, Vol. 10, No. 1, 2001, pp. 68–75;  J.W. Harris et al., “Morphology of monocrystalline diamond and its inclusions,” Reviews in Mineralogy and Geochemistry, Vol. 88, No. 1, 2022, pp. 119–166). Defects in the diamond structure such as lattice dislocations are local areas of structural weakness, which are more susceptible to etching. In this diamond, multiple narrow etch channels originate from a single surface opening (figure 3), reflecting selective diamond dissolution as fluids permeated through the stone.

Figure 4. Trigons visible in a subsurface diamond etch channel. Photomicrograph by Mei Yan Lai; field of view 1.00 mm.
An intriguing feature observed along the walls of the internal etch channels consisted of multiple triangular etch pits known as trigons (figure 4). Trigons are one of the most common features found on the surfaces of rough diamonds, with various sizes, depths, and shapes (e.g., flat- or point-bottomed, attributed to etching by oxidizing fluids/melts; Harris et al., 2022). When present on diamond surfaces, trigons are restricted to the octahedral crystal face and may occasionally form parallel rows that follow the orientation of plastic deformation lines (often called “grain lines” in the trade, caused by dislocation of carbon atoms along octahedral planes). In faceted diamonds, trigons are usually removed by polishing but are occasionally preserved on the girdle. Conversely, trigons reported within internal diamond etch channels are extremely rare (Lu et al., 2001). The occurrence of trigons within a subsurface channel indicates etching along the octahedral crystal face of this diamond. @chapter:29 @chapter:1 @chapter:29


# Publication Year: 2023
# Title: Natural Diamond with Unusual Phosphorescence
# Abstract: These deep-UV (<225 nm) phosphorescence images of the table (left) and pavilion (right) in a 0.90 ct D-color natural diamond with very low boron showed localized areas of the 500 nm (greenish blue) and 660 nm (red) bands. Images by Evelina Goldort.
Phosphorescence spectroscopy shows that natural type IIb diamonds can have two broad phosphorescence bands: one centered at 500 nm that appears greenish blue and one centered at 660 nm that appears red. Generally, one of these phosphorescence bands is dominant. In the Hope diamond, for example, the phosphorescence initially appears orangy red and transitions to red as the subordinate greenish blue phosphorescence fades away (S. Eaton-Magaña et al., “Using phosphorescence as a fingerprint for the Hope and other blue diamonds,” Geology, Vol. 36, No. 1, 2008, pp. 83–86). Occasionally, the faster-decaying greenish blue phosphorescence band will transition to the slower-decaying red band (Spring 2007 Lab Notes, pp. 47–48).
Recently, a 0.90 ct diamond with D color and I1 clarity was submitted to GIA’s laboratory in Ramat Gan, Israel, for a diamond dossier report. Infrared (IR) absorption spectroscopy indicated that the natural diamond was nominally type IIa. However, photoluminescence (PL) spectroscopy revealed that the diamond contained boron-related features, including the 648.2 nm peak attributed to a boron interstitial (B. Green, “Optical and magnetic resonance studies of point defects in single crystal diamond,” PhD thesis, University of Warwick, 2013), along with the observed phosphorescence. These features indicated that the diamond did contain boron, but below the detection level of IR absorption spectroscopy. The distinctive aspect was that both the red and greenish blue phosphorescence were localized and visible within the same image (see above).
The phosphorescence is attributed to donor-acceptor pair recombination. For the 500 nm band, this recombination has been identified as interactions between boron acceptors and isolated nitrogen donors (J. Zhao, “Fluorescence, phosphorescence, thermoluminescence and charge transfer in synthetic diamond,” PhD thesis, University of Warwick, 2022), while the 660 nm band is attributed to boron acceptors and unknown donors that are likely related to plastic deformation (S. Eaton-Magaña and R. Lu, “Phosphorescence in type IIb diamonds,” Diamond and Related Materials, Vol. 20, No. 7, 2011, pp. 983–989). PL maps were collected on the table and pavilion with 455, 532, and 785 nm excitation; only an undefined PL feature at 813 nm showed an apparent increase on the pavilion within the red-phosphorescing region (see above, right).
Type IIb diamonds grown by high-pressure, high-temperature (HPHT) methods almost always show the 500 nm phosphorescence and occasionally a separate orange phosphorescence band centered at 580 nm. In a few instances, HPHT-grown diamonds have shown the 500 and 580 nm bands simultaneously in different portions of the diamond (Eaton-Magaña and Lu, 2011; Spring 2023 Gem News International, pp. 155–156).
This is the first time the authors have seen spatially distinct observations of red and greenish blue phosphorescence in a natural diamond, an unusual find. @chapter:22 @chapter:1 @chapter:22


# Publication Year: 2015
# Title: Color-Change Synthetic Cubic Zirconia as Peridot Imitation
# Abstract: This synthetic cubic zirconia imitation of peridot, with an estimated weight of 4.50 ct, is shown in daylight (left) and incandescent light (right). Photos by Igor Iemelianov; field of view 13.20 mm.

	Peridot is a common gemstone in the jewelry industry; however, it is rarely simulated using substances other than glass (Summer 2004 Lab Notes, p. 165). The State Gemological Centre of Ukraine recently received for identification an oval-cut gemstone, with an estimated weight of 4.50 ct, set in a ring. The stone was greenish yellow in daylight, as seen in the image on the left, and orangy yellow in incandescent light (right). The client who submitted the ring specifically wished to know if the center stone was peridot. The sample was transparent and isotropic, with a refractive index of 2.150 (measured by a refractive index meter) and was inert to both short-wave and long-wave UV radiation. Microscopic examination revealed no inclusions. The measured relative reflectivity (RR 65–67), obtained using a Presidium DuoTester, clearly matched that of cubic zirconia, a result in line with the other gemological observations. This allowed us to identify the stone as cubic zirconia. Chemical analysis with energy dispersive X-ray fluorescence (EDXRF) showed Zr and Y, with minor Pr and Nd. These impurities can cause color change in this stone. Using fiber-optic light with the spectroscope, we observed a complex set of absorption lines in both the orange and green-blue regions (the same measurement can be seen at http://www.gemlab.co.uk/peridot.html). This study shows the importance of studying a variety of simulants, even those for less-expensive gems such as peridot. @chapter:18 @chapter:1 @chapter:18


# Publication Year: 1990
# Title: Fall 1990 G&G Lab Notes
# Abstract: Dyed Natural Beryl
Carved Chrysoberyl
Electron Irradiated Diamond
Fancy Black Diamond
Included Diamond Crystal
Opal with an Unusual Inclusion
Cultured Pearls with Colored Bead Nuclei
Freshwater Natural Pearls
Gray Baroque Cultured Pearls
Diffusion-Treated Montana Rough Sapphire
Large Colorless Sapphire
Cobalt Colored Color-Change Spinel
Synthetics and Simulants in Period Jewelry

To view the full section, download the PDF above. @chapter:18 @chapter:1 @chapter:18


# Publication Year: 2022
# Title: Rare Blue Apatite Inclusion in Smoky Quartz
# Abstract: Figure 1. A hexagonal apatite inclusion in smoky quartz. Photomicrograph by Nattapat Karava; field of view 6.3 mm.
A natural smoky quartz with an obvious mineral inclusion at the center of the stone (figure 1) was recently observed by the author. Raman analysis confirmed that this mineral was apatite. The apatite had very light blue color and a hexagonal twinned morphology. Under cross-polarized light, the inclusion showed interference colors, confirming its doubly refractive nature (figure 2).

Figure 2. A hexagonal apatite inclusion with interference colors in smoky quartz, viewed in cross-polarized illumination. Photomicrograph by Nattapat Karava; field of view 6.3 mm.
Apatite is a phosphate mineral with the chemical formula of Ca5(PO4)3(Cl/F/OH). Generally, smoky quartz and apatite can occur under the same geologic conditions, including pegmatitic hydrothermal environments. Apatite is commonly a protogenetic inclusion, but it can occasionally result from a later stage and be considered a syngenetic inclusion in quartz. The rounded shape of this apatite example suggests a protogenetic inclusion, one that would be a welcome sight for any gemologist examining stones in a microscope. @chapter:15 @chapter:0 @chapter:15


# Publication Year: 2006
# Title: The Cause of Iridescence in Rainbow Andradite from Nara, Japan
# Abstract: “Rainbow” andradite from Nara, Japan, occurs as relatively small orangy brown crystals that show attractive iridescence in almost the entire range of the spectrum. The material is nearly pure andradite, as determined by its chemical composition and Vis-NIR and specular reflectance FTIR spectra. Microscopy revealed that two different types of lamellar structures appear to be responsible for the iridescent colors. These lamellar structures cause predominantly thin-film interference and most likely diffraction of light. The terms interference and diffraction are explained and correlated to the structure and iridescence observed in these garnets. @chapter:3 @chapter:0 @chapter:3


# Publication Year: 2013
# Title: Amber with Insect-Bearing Filling
# Abstract: Figure 1. The beads in this strand of prayer beads measure approximately 12 mm in diameter. Photo by Sutas Singbamroong.

              We recently tested an interesting strand of Islamic prayer beads resembling amber (figure 1). It consisted of 33 round yellow beads approximately 12 mm in diameter, two oval-shaped separators, and a fancy-shaped link. It was purchased as amber from a dealer at an annual festival in Dubai.

The round beads contained dark brown plant debris and a variety of insects: ants, flies, and spiders, all in good condition. The beads’ surfaces also featured noticeable circular zones, and when exposed to long-wave UV radiation, they displayed a weak, blue fluorescence and distinctive chalky blue circular areas (figure 2). The beads were inert to short-wave UV radiation.

	Figure 2. When exposed to long-wave UV radiation, these beads displayed weak blue fluorescence and distinct, chalky blue circular areas. Photo by Sutas Singbamroong.
These features were similar to those of copal filled with plastic (Winter 2010 GNI, pp. 326–328). We obtained spot RI readings of 1.52 on the circular zones and 1.54 elsewhere. Next, we analyzed the strand using Raman spectroscopy with a 785 nm diode laser. The separator link and the main portion of the beads showed peaks between 1434 and 1644 cm–1, consistent with amber. The circular areas’ strong bands at 623, 807, 1100, and 1599 cm–1 were consistent with epoxy resin (figure 3).

	Figure 3. Raman spectra collected from the main portion of the beads were consistent with amber, whereas the circular areas indicated an epoxy resin.
Microscopic examination with immersion in water indicated that all the round beads had been cored and filled (figure 4). The beads were identified as amber filled with colorless to light yellow plastic to imitate insect-bearing amber.

	Figure 4. Microscopic observation with immersion in water clearly indicated that these amber beads had been cored and filled with a colorless to light yellow plastic containing insects. Photomicrographs by Sutas Singbamroong; magnified approximately 10×. @chapter:46 @chapter:4 @chapter:46


# Publication Year: 2018
# Title: Turquoise from Western Arkansas
# Abstract: Figure 1. Recent production from a reactivated turquoise deposit in Polk County, Arkansas. The beads shown here measure up to 25 mm in diameter, while the largest cab weighs 30 ct. Photo by Robert Weldon/GIA.

At their AGTA booth, Avant Mining (Jessieville, Arkansas) displayed an unexpected material: turquoise from Polk County, Arkansas. According to owner James Zigras, this is the only gem-quality turquoise deposit in the U.S. located outside the Southwest. Calibrated goods and specimens ranging from blue-green to greenish blue were on view (figure 1). Also at the booth was a 245 lb. boulder unearthed in 1982 and polished in 2018 by Michael Beck (Copper Canyon Lapidary & Jewelry, Sedona, Arizona). The boulder, shown in figure 2, is the largest known American turquoise nugget.

Figure 2. This 245 lb. boulder of turquoise, removed from the Polk County deposit in 1982, is the largest known American turquoise nugget. Photo by Robert Weldon/GIA.
The source was first mined from 1978 to 1986 under a previous owner, but the material was likely sold as Southwestern turquoise. During these years, there was too much competition in the market for stabilized turquoise, and activity eventually ceased. In 2017, Zigras bought the previous owner’s estate, which included two tons of turquoise rough, and restaked a claim on the original mining site. He expected the source to yield planerite and was surprised to find that the material was close to ideal for the turquoise end member of the planerite-turquoise solid solution series. In January 2018, a test trench was worked for seven days. In that time, the deposit produced approximately 1,000 lbs. of turquoise and an old mine shaft was uncovered. Veins are located about 10 feet below the surface (see video below). Quartz crystals and wavellite are also found in the deposit.

Turquoise VeinsThe veins of turquoise are close to the surface of the Arkansas deposit, as seen in this short video.
Zigras indicated that the turquoise is impregnated but not dyed. Independent testing at GIA confirmed impregnation; no evidence of dye was detected on the samples. Zigras plans to submit the material for Zachery treatment, a process designed to improve the polish and color of turquoise. It will be interesting to see this source’s output in the coming years. @chapter:4 @chapter:0 @chapter:4


# Publication Year: -
# Title: Fall 2012 Gem News International
# Abstract: Colored Stones and Organic Materials
            Beryl from Kaduna State, Nigeria
            Green and Orangy Yellow Calcite from Pakistan
            Citrine from Zambia
            Emerald from Ethiopia
            Emerald from Sumbawanga, Tanzania
            Gold in Trondhjemite Matrix Rock
            Hemimorphite from China
            Update on Some Mogok Gem Mines and Markets
            Rainbow Moonstone from Madagascar
            Yellow Muscovite from Brazil
            Blue Opal from Arizona Showing Play-Of-Color
            Yellow Opal from West Africa
            Quartz with Green Rutile Inclusions
            Quartz from Tanzania with Red Epidote-Piedmontite Inclusions
            Unusual Trapiche Sapphire
            Stichtite-Dominated Intergrowths with Serpentinite from Tasmania
            Zoisite from Pakistan
            Pink to Purple Zoisite from Merelani, Tanzania
Synthetics and Simulants
            Artistic Cutting of Russian Synthetic Moissanite
            “True” Red Synthetic Spinel Grown By a “Pulled” Technique in Russia
Miscellaneous
            Automated Colored Stone Cutting

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


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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

	This GIA Field Expedition (FE65) took place in 2015. Besides Pardieu, the participants were video cameramen Didier Barriere-Doleac and Didier Gruel, and expedition members Manny Diaz, Philippe Labrot, Lucie Martinez, Lauriane Pinsault, and Wim Vertriest. @chapter:30 @chapter:0 @chapter:30


# Publication Year: 2023
# Title: Inclusion Resembling a Gada in Diamond
# Abstract: This etch channel seen in the crown facets of a 1.00 ct diamond with SI1 clarity (left) resembled a gada (right), a mace-like weapon wielded by the Hindu god Hanuman. Photomicrograph (left) by Deepak Raj; field of view 0.80 mm. Photo (right) courtesy of the Metropolitan Museum of Art.
Recently, the authors observed an interesting etch channel (see above) in a 1.00 ct L-color type Ia round brilliant diamond with SI1 clarity. It resembled a gada, a mace-like weapon belonging to the Hindu god Hanuman. This etch channel was the only one observed in the diamond; these features are often created by dissolution processes (T. Lu et al., “Observation of etch channels in several natural diamonds,” Diamond and Related Materials, Vol. 10, No. 1, 2001, pp. 68–75).
This unusual clarity characteristic showcases the variety that is possible within the natural world. @chapter:39 @chapter:1 @chapter:39


# Publication Year: 1982
# Title: Summer 1982 Gem News International
# Abstract: Diamonds
            Australia: DeBeers CSO to Market Ashton Join Venture Stones
            Botswana: Depressed Market Creates Severe Economic Problem
            Ghana: Only Producing Mine Continues through U.S. Loan
            India: Government Plans to Increase Domestic Supplies
            Israel: Customs Duty Removed
            Lesotho: Mine Closure Due to Recession
            Namibia: Production Reduced
            South Africa: Coping with Depressed Market
            U.S.: West Coast Club Opens
            Zaire: Substantial Drop in Production
Emerald
            Australia: Aga Khan Mine Output Stockpiled
            Brazil: Superior Color Discovered
Pearl
            Japan: Concern About Chinese Freshwater Pearls
Topaz and Peridot Jewelry Suite Currently on Display at GIA

To view the full section, download the PDF above. @chapter:50 @chapter:3 @chapter:50


# Publication Year: -
# Title: Ruby Quality Factors
# Abstract: Fine-color, large, and eye-clean (lacking visible inclusions) rubies like this 11.01carat (ct) stone from Myanmar (formerly known as Burma) are extremely rare and valuable. – Photo: Robert Weldon/GIA. Courtesy: Jan Goodman Co

Ruby can command the highest prices of any colored gemstone.  The per-carat prices of fine-quality rubies have been rising consistently, many times breaking auction records.

For better-quality material, slight differences in color can make significant differences in value. For top-color ruby that’s also free of eye-visible inclusions, the price rises even more.

The per-carat price of ruby can also increase dramatically as size increases, especially for better-quality stones.
The Color of Ruby

The mixture of these untreated and heat-treated rubies show a range of darker and brighter red colors. Photo: Robert Weldon/GIA. Courtesy: Tommy Wu, Shire Trading Ltd., Hong Kong
Color is the most significant factor affecting a ruby’s value. The finest ruby has a pure, vibrant red to slightly purplish red color. In most markets, pure red colors command the highest prices and ruby with overtones of orange and purple are less valued. The color must be neither too dark nor too light to be considered finest quality. If the color is too dark, it has a negative effect on the stone’s brightness. At the other extreme, if the color is too light, the stone may be considered to be a pink sapphire, even if color strength or intensity is high. That said, pink sapphires enjoy a following, at a far more competitive prices than rubies. Ultimately, the most desirable color of ruby is the one you prefer the most.
The Difference Between Pink Sapphire and Ruby
Some gem dealers debate the borderline between ruby and pink sapphire. Historically, the word ruby referred to shades of red, which technically included pink. There are also cultural differences in the interpretation of ruby versus pink sapphire. In some gem-producing nations such as Sri Lanka, pink colors were always considered ruby, while in many consuming countries it is classified as pink sapphire.

The GIA Laboratory uses a controlled set of comparison stones called masterstones to determine if corundum is ruby The laboratory grades its masterstones on the principle that red must be the dominant hue before a stone can be called a ruby. In the gem trade, though, pinpointing the dominant hue is subject to personal perception.
Burmese Pigeon Blood Ruby
Historically, the term “pigeon’s blood” described the red to slightly purplish or pinkish red color of rubies with a soft, glowing, red fluorescence.

Traditional descriptions like these are useful for evoking images and describing color among professionals. But they can be subject to misinterpretation when used to describe a ruby’s actual color.

Over time and years of experience trade terms can conjure up perceptions of certain colors and qualities that are associated with a stone’s source. However, the qualities might be typical of that source or they might represent the finest stones from that source.

A single source never yields gems that are all the same color and quality. In fact, the descriptive trade term might represent only a small, yet highly desired percentage of stones from that source.

New sources can produce material very similar to rubies from classical localities or present a slightly different appearance, but remain just as beautiful.
Ruby Clarity

Intersecting needles of the mineral rutile create a common ruby inclusion called silk. When they are intact, they prove the ruby was not heat-treated at very high temperatures. It’s still possible that lower-temperature heat treatment might have occurred. Photo: John I. Koivula, GIA.
People in the trade expect rubies to have at least some inclusions because inclusion-free rubies are practically nonexistent. Ruby value can depend on how visible the inclusions are. Obvious inclusions, or inclusions that reduce transparency or brightness, lower a ruby’s value dramatically.

If large and prominent inclusions are located under the table facet, they greatly diminish the transparency, brilliance, and value of the stone. Inclusions can also limit a ruby’s durability. Significant surface-reaching fractures can pose durability threats.

Typical ruby clarity characteristics include thin mineral inclusions called needles. When the mineral is rutile and needles are present in intersecting groups, it is called silk. Needles might be short or long and slender, and they might appear to be woven tightly together.

Ruby can also contain needles composed of other minerals, small crystals, zones of color variation, or inclusions that resemble fingerprints.

Some inclusions can actually contribute positively to a gem’s appearance. The presence of rutile silk causes light to scatter across facets that might otherwise be too dark. This adds softness to the color and spreads the color more evenly across the ruby’s crown.

Needles that intersect can also cause the star effect, called asterism, when the stone is cut with a curved upper surface, called a cabochon cut.

Long mineral inclusions that intersect can create the star effect when stones are cut as cabochons. - Photo: Robert Weldon/GIA. Courtesy: Hussain Rezayee, Rare Gems & Minerals
Ruby Cut

Rubies are commonly cut into oval and cushion shapes. – Photo: Robert Weldon/GIA. Rough: Gift of William F. Larson. Cut stone: Courtesy: Edward Boehm.
Several factors affect the cut and proportion of rubies on the market. A ruby’s crystal shape dictates its suitability for certain cuts. The most common shape is a flat tabular hexagonal shape, but ruby crystals from some sources can be elongated.

To accommodate these crystal shapes, the most common shapes of fashioned rubies are ovals and cushions, with brilliant-cut crowns of kite-shaped and triangular facets, and step-cut pavilions with concentric rows of rectangular or square facets.

Round, triangular, emerald-cut, pear, and marquise rubies are also available. But these shapes are rare in larger sizes and higher qualities.

Ruby rough is very expensive, so many cutters try to conserve as much weight as possible. They might fashion flattened ruby rough into shallow stones, even though light escapes through flattened pavilions, causing an unattractive see-through area in the stone called a window.

Pleochroism—the appearance of different colors in different crystal directions—is another factor that influences cut. In ruby it typically appears as red to purplish red in one crystal direction and orangy red in the other. Cutters can minimize the orangy red color by orienting the table facet perpendicular to the long crystal direction. Even so, it’s not always possible to orient a ruby for ideal color return because the potential loss of weight would be too great.
Ruby Size and Weight

These rubies were all mined in Myanmar (formerly known as Burma). The faceted stone weighs 11.55 carats and the rough stones weigh between 16.65 carats and 278.50 carats. Photo: Robert E. Kane/GIA.
Fine-quality rubies over one carat are very rare, but commercial-quality rubies are commonly available in a wide range of sizes. The price per carat goes up significantly for ruby as it increases in size. @chapter:31 @chapter:2 @chapter:31


# Publication Year: 2018
# Title: Opal from West Java, Indonesia
# Abstract: Figure 1. These cabochons, weighing 6.94 ct and 3.79 ct, were among the Indonesian opals at Rare Earth’s AGTA booth. Photo by Robison McMurtry.

At the AGTA show, Rare Earth Mining Co. (Trumbull, Connecticut) displayed an unexpected material: Indonesian opal reportedly from West Java. Two cabochons (figure 1) yielded a refractive index of 1.45 and a specific gravity of 2.13, consistent with opal. Energy-dispersive X-ray fluorescence (EDXRF) analysis revealed the presence of copper.

According to Rare Earth’s Curt Heher, the material was first seen in the spring of 2017. While the opal comes in a wide range of colors, including browns and blues, the greenish blues were of particular interest. Rare Earth displayed cabochons where this was the primary hue, with the accessory colors distributed in an aesthetically pleasing manner. @chapter:48 @chapter:0 @chapter:48


# Publication Year: -
# Title: 2017 Gianmaria Buccellati Foundation Award for Excellence in Jewelry Design Showcases Jewelry Art
# Abstract: This close up of the pendant on Catherine Zheng’s Art Deco-inspired necklace showcases the blue sapphire, tanzanite, diamonds and enamel she used in her design.

Judges for the first annual Gianmaria Buccellati Foundation Award for Excellence in Jewelry Design were surprised when they saw the display of original hand-painted renderings from GIA's Jewelry Design Certificate program students on display in Tucson recently.

“The judges were so surprised. They walked in and said ‘Wow,’” Elizabeth Brehmer, director of GIA’s Jewelry Manufacturing Arts (JMA) program, said. “The renderings are really lifelike and executed at the right size and scale. They are colorful and lively and really jump off the page.

“There is a life to something that you render and paint,” she said. “There’s something very personal, organic and real about it.”

The Gianmaria Buccellati Foundation Award for Excellence in Jewelry Design competition was created to inspire and encourage beginning jewelry designers and celebrate the long history of hand-sketched and painted jewelry art for which Gianmaria Buccellati was known.

“Mr. Buccellati always protected his brand and ensured that the things that came out of his workshop were unique, special and always maintained a very high standard," Brehmer said. "Having a competition with the foundation’s name attached to it really speaks volumes to recognizing the work GIA student finalists provided for the judging.”

The competition was open to individuals who successfully completed the 2017 Jewelry Design Certificate program at any GIA school worldwide. The students' original works of art go through a couple of different gates of judging, according to Brehmer. First, they complete the course and showcase their work to their peers at each of the schools, then the paintings are submitted to a committee in Carlsbad to make sure they meet all of the standards and criteria taught at GIA. This year, 12 global design courses were offered and one student from each course at each school (Carlsbad, Hong Kong, India, New York, London, Taiwan and Thailand) was selected to participate.

Along with an original rendering, each entry had a material statement and an inspiration statement.
“The material and inspiration statements are a significant part of the concept and execution of the rendering – and are a critical part of the judging in the final round,” Brehmer said. “Their compelling inspiration stories contributed to their art.”

Zheng with Larry French, chief officer of North American strategies for the Gianmaria Buccellati Foundation, who will help her plan her trip to Italy. Photo by Kevin Schumacher/GIA
Brehmer said this type of competition is important for GIA students to participate in because it gives them a chance to showcase their designs to experts in jewelry design.

“The students were so excited when the announcement about the competition was made,” Brehmer said. “There’s not another competition out in the market that allows them to showcase the skills they learn as an artist and as a designer when they go through a jewelry design program at GIA, anywhere in the world.”

A panel of five industry experts from a variety of aspects of jewelry design did the final judging the morning of the “Party at the GIA Gem Mine” alumni event in Tucson: Molly Bell, executive vice president of Rio Grande Tools & Supplies; Remy Rotenier, president of Remy Design and a jewelry designer and educator; Ginger Porcella, chief curator of the Tucson Museum of Contemporary Art; Alishan Halebian, owner of Alishan, a retail and custom design-curated company; and Victoria Gomelsky, editor-in-chief of JCK magazine.

Doug Hall, a senior instructor in GIA’s JMA program, provided an overview of GIA’s Jewelry Design Certificate program to the judges before they began the process of selecting a winner, including what students learn, how they learn it, the perspective they are asked to employ, and the techniques they use.

Brehmer said the judges were impressed by the quality of the GIA students’ work and were thrilled they could pick the renderings up to examine them and then read the student’s comments on what inspired them and the materials they would use make the piece.

“The judges said they rarely get to see original renderings and several commented on the time and effort that went into this type of work. One judge noted that it really afforded an opportunity to close a sale quicker because the customer would see what something was really going to look like,” she said. “That was an interesting dialogue between the judges, because it’s a very traditional method [painting renderings] that you can apply in today’s industry.”

View Gallery

The grand prize winner of the competition – Catherine Zheng – was announced during a formal presentation at the alumni event. Her platinum and tanzanite Art Deco-style necklace impressed the judges with its elegance, beautiful rendition and the fact that it could be manufactured, Brehmer said.

Zheng, a Los Angeles area real estate broker for high-end clients, was “totally shocked” when her name was announced as the grand prize winner.

“I never thought that I'd win this competition because I know there are many students in the jewelry design course who are very talented – and a lot of them either studied art in college or they already have a jewelry industry background,” she said.

Zheng said she makes a good income in real estate, but always felt like something was missing in her life.

“I was really into art while I was in high school and I earned multiple art rewards, such as the National Award for Creative Artists and a Special Congressional Recognition in ‘An Artistic Discovery.’ My dream was to become a designer, but my family, like many traditional Asians, thought it was too risky to become an artist,” she said.

So Zheng studied finance and marketing in college and become a banker and then a real estate broker after she graduated. She said her creative art ideas kept pulling at her, however, so she signed up for the Jewelry Design Certificate program course in Carlsbad. Hall, who she calls “awesome,” was her instructor.

“Doug is a perfectionist and I really learned a lot by his high standards,” she said. “The course is only nine weeks long, but we learned so much about technique and skills during this short period of time. Not only that, the second half of the course gives the students a lot of room to be creative.”

Catherine Zheng’s Art Deco-inspired necklace features blue sapphire, tanzanite, diamonds and enamel. An ornate pendant hangs from a chain with stations of embellished links in between the chain.
Zheng continued to work her real estate business while she took the course.

“The challenging part was that I had to work at night after my day job and could only sleep four to six hours every day to fit it all in,” she said. “I haven't drawn for more than 10 years, but I'm very glad that I put in my best effort while studying.”

She said all of the hard work is extremely rewarding. “It really feels great to win when you didn't expect it,” she said.

Beyond the recognition Zheng received as grand prize winner, she will go on a one week all-expense paid trip to Florence to take in Renaissance art and view part of the jewelry collection of Gianmaria Buccellati housed in the Pitti Palace. She will also travel to Milan and have the opportunity to meet Mrs. Buccellati, where she will receive a plaque acknowledging her as the winner of the competition.

“I'm super excited to go to Italy. I have been there a few times before, but this is sure to be the most exciting and memorable trip,” she said. “I am very much looking forward to meeting Mrs. Buccellati.”

Zheng said winning the Gianmaria Buccellati Foundation Award for Excellence in Jewelry Design has inspired her to continue to pursue her professional jewelry design dreams – which is exactly why it was created – and she plans to study CAD/CAM design and become a GIA Graduate Gemologist in the near future.

“I'm definitely looking into starting my career as a jewelry designer or even my own line of jewelry,” she said. “This means so much to me as a beginning designer and it really gives me a lot of encouragement and faith to continue on this career path.” @chapter:20 @chapter:2 @chapter:20


# Publication Year: -
# Title: Colombian Emerald Industry: Winds of Change
# Abstract: Independent miners at the Rio Itoco in the Muzo Valley. This husband and wife mining team worked the tailings MTC (Mineria Texas Colombia) dumped by the river for local independent miners to go through. They are examining a significant rough emerald they found. Photo by Andy Lucas/GIA

Andy Lucas, GIA’s education manager of field gemology, researches and documents the mine to market journey of gemstones. Lucas shares the changes he observed in Colombia’s major emerald mining and cutting areas in a presentation he made at the 2017 JCK Las Vegas show.
Lucas interviewed local participants in the emerald trade to see what is causing changes in Colombia’s emerald business. He learned that there is a generational shift in approaches to mining and that the government is working to standardize the industry. The main effort is focused on combining traditional and modern mining methods to advance Colombian emeralds in the global market.
In the video, Lucas discusses the five pillars of the Colombian government’s mining plan, introduced in October 2015 during the Emerald Symposium in Bogotá. The plan is meant to formalize, regulate and provide help for geological studies and infrastructure. The goal is to create a balance for the country’s indigenous people and the publicly traded companies.

	Colombian Emerald Industry

Before joining GIA, Lucas founded and operated an international wholesale and private client retail gemstone jewelry and antiquity business. He began his GIA career as an instructor, and later developed educational products before becoming education manager of field gemology. He has published articles, created documentaries and presented lectures at countless international seminars. @chapter:50 @chapter:3 @chapter:50


# Publication Year: 2021
# Title: Thin-Film Fluid Inclusions in Aquamarine
# Abstract: Thin-film fluid inclusions oriented perpendicular to the c-axis of this aquamarine display interference colors when viewed using oblique fiber-optic illumination. Photomicrograph by Muzdareefah Thudsanapbunya; field of view 2.79 mm.

The author recently examined a faceted aquamarine from Brazil that showed two-phase (liquid and gas) thin-film inclusions of different sizes and shapes. When observed using oblique fiber-optic illumination, the inclusions revealed a kaleidoscopic play of interference colors (see above). The most diagnostic beryl inclusions, yet barely noticeable in brightfield illumination are ultra-thin-film fluid inclusions. The planar surface of these inclusions is oriented parallel to the basal pinacoid of their host (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Volume 2, Opinio Publishers, Basel, Switzerland, 2005, pp. 312–314). The presence of the bright iridescent thin-film fluid inclusions resembles colorful rainbow sprinkles. @chapter:19 @chapter:0 @chapter:19


# Publication Year: 2024
# Title: Large Freshwater Cultured Pearls with Atypical Bead Nuclei
# Abstract: Figure 1. These two necklaces consisting of large freshwater cultured pearls displayed strong hues with orient. Photos by Sood Oil (Judy) Chia; courtesy of Yvel.
Freshwater cultured pearls are known for their wide range of attractive colors, including different combinations of white, orange, pink, and purple hues. In the past decade, round or near-round freshwater bead cultured pearls of large size, commonly called “Edison” pearls in the trade, have gained popularity (Summer 2015 Lab Notes, pp. 179–181; C. Zhou et al., “Detection of color treatment and optical brightening in Chinese freshwater ‘Edison’ pearls,” Summer 2021 G&G, pp. 124–134). Recently, two necklaces consisting of large pearls of mostly orangy pink to purplish pink colors (figure 1), ranging in size from 15.40 to 17.42 × 16.70 mm and from 18.00 to 19.96 × 19.06 mm, were submitted to GIA’s New York laboratory. The strands caught our attention for their size and intense colors, as well as the growth features found inside these pearls.

Figure 2. RTX analysis revealed the near-round atypical bead nucleus used to culture each of the pearls.
Real-time X-ray microradiography (RTX) revealed that all the pearls were bead cultured—but not with the shell bead nuclei typically used for cultured pearls. Instead, a more X-ray transparent material with a distinct outline and near-round shape was found inside them (figure 2). The material appeared porous and nonuniform and did not resemble the “mud-like” material found in “soufflé” freshwater cultured pearls previously studied (Spring 2010 Gem News International, pp. 61–63). However, the exact nature of this material could not be determined. Energy-dispersive X-ray fluorescence analysis of their trace elemental concentrations (such as manganese and strontium) confirmed that the pearls were grown in a freshwater environment. Furthermore, Raman spectroscopy using 514 nm laser excitation indicated that their colors were natural, with two strong peaks around 1125 and 1510 cm–1 associated with natural polyenic pigment.
Cultured freshwater pearls with large size, near-round shape, and intense coloration are highly sought after and more valuable than traditional freshwater cultured pearls. These large freshwater cultured pearls are especially noteworthy because of the unique bead nuclei used during the culturing process, which suggests that culturing techniques are continuously evolving, resulting in higher-quality products. @chapter:11 @chapter:4 @chapter:11


# Publication Year: 2009
# Title: “Fluorescence Cage”: Visual Identification of HPHT-Treated Type I Diamonds
# Abstract: HPHT-treated type I diamonds of various colors may exhibit unusually intense fluorescence at the facet edges and junctions. This effect, here named the “fluorescence cage,” is observed with a fluorescence microscope as a luminous network on the diamond’s surface. It was not observed in untreated diamonds or colorless type IIa HPHT-treated diamonds. This fluorescence pattern is believed to result from a high concentration of HPHT-induced optical centers, which remain on facet edges after repolishing. @chapter:9 @chapter:1 @chapter:9


# Publication Year: 1993
# 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. @chapter:19 @chapter:1 @chapter:19


# Publication Year: 1995
# Title: Fall 1995 Gem News International
# Abstract: Diamonds
            Diamond with Mobile Diamond Inclusion
            Update on Russian Diamond Mining
            Spy Ship Looks for Diamonds
Colored Stones
            Cat's-Eye Apatites from Madagascar
            "Eilat Stone" from Israel and Peru
            Six-Rayed Star Emerald
            Faceted Genthelvite: A Gemological First
            "Drusy" Hausmannite
            Costa Rican Jade Museum
            Green Opal from Serbia
            "Deep" Quartz from Africa
            Egyptian Green Quartz
            Quartz with "Hematite" Inclusions
            Aromatic Resin Necklace: A form of Myrrh?
            Update on Mong Hsu Ruby
            Rubies and Sapphires from North Carolina
            Purple Scapolite from Tajikistan
            Large Spinel from Tajikistan
            Color-Change Zircons
Enhancements
            Impregnated Malachite
Synthetics and Simulants
            Unusual Color-Zoned Synthetic Amethyst
            More on Czochraski "Pulled" Synthetic Sapphires
            Tanzanite-Colored Synthetic Sapphire
            Natural and Synthetic Quartz "Constructs"
Announcements
            Dates Set for February 1996 Tucson Shows
            Education at the Tucson AGTA GemFair
            Visit Gems & Gemology in Tucson
            More GIA Tucson Show News

To view the full section, download the PDF above. @chapter:2 @chapter:0 @chapter:2


# Publication Year: 2016
# Title: Non-Nacreous Purple and White Pearls Reportedly from Spondylus Species
# Abstract: Figure 1. These three purple and white non-nacreous pearls weighing 7.85, 8.37, and 9.85 ct (left to right) are reportedly from Spondylus calcifer. Photo by Robert Weldon.

The Carlsbad laboratory recently examined three non-nacreous pearls, weighing 7.85 to 9.85 ct and measuring from 10.50 × 10.21 mm to 12.43 × 11.65 × 10.65 mm (figure 1). All three pearls exhibited similar uneven bodycolors and surface characteristics. They displayed purple and white colors with some yellowish brown tints and possessed a porcelaneous surface with mottled to clear fine flames. They were reportedly fished near Ligui, on the eastern coast of the Mexican state of Baja California Sur.

Similar surface structures have been reported in G&G (Fall 2014 Lab Notes, pp. 241–242; Winter 2015 Lab Notes, pp. 436–437; Summer 2016 Micro-World, pp. 202–203). A characteristic reflective blue coloration on the base of the 9.85 ct semi-baroque button (figure 2) was clearly visible when the flame structure was illuminated with a fiber-optic light. Moreover, subsurface to surface-reaching acicular inclusions found in most Spondylus pearls examined previously were also present in these samples. These inclusions, which appear in the form of tubes or needles, are often associated with the flame structure. At first the inclusions were believed to be parasite channels, which are sometimes observed in shells and pearls of various nacreous and non-nacreous mollusks. But after careful inspection they were seen to be part of the structure, radiating from within and reaching the surface in the same direction and with fairly consistent size and shape—whereas the parasite channels are irregularly shaped and in various sizes, running in random directions and usually crossing over each other.

Figure 2. The characteristic reflective blue coloration of Spondylus pearls was visible
within the flame structure of the semi-baroque button pearl when illuminated with a
fiber-optic light. Photomicrograph by Artitaya Homkrajae; field of view 5.77 mm.
The pearls’ dimpled surface texture appears to be caused by the slightly recessed openings where these inclusions reach the surface. This unique feature is also found on the interior of Spondylus shells in GIA’s Bangkok laboratory collection (figure 3). The resemblance between a pearl’s surface and the interior surface of its host are useful in identifying the mollusk species. Yet many marine gastropods and bivalves produce non-nacreous pearls, and their similar surface structure and color sometimes make mollusk identification challenging. As with the previously reported Spondylus pearls, microradiography of all three pearls revealed tight structures, and no obvious growth arcs were seen.

Figure 3. Subsurface to surface-reaching acicular inclusions were found on the interior of a Spondylus shell (left) from the GIA Bangkok reference collection and associated with the flame structure in a Spondylus pearl (right). Photomicrographs by Artitaya Homkrajae (left, field of view 1.31 mm) and Moqing Lin (right, field of view 2.37 mm).
The Spondylus genus (commonly known as “thorny” or “spiny” oyster) consists of about 76 living species distributed in tropical waters around the world. Spondylus princeps and Spondylus calcifer (also known as Spondylus limbatus) are two of the main species on the western coast of the Americas. S. princeps is found from the gulf side of Baja California down the Pacific coast of Mexico through Panama to northwest Peru. S. calcifer is found in the Sea of Cortez (Mexico) and Ecuador (K. Lamprell, Spiny Oysters: A Revision of the Living Spondylus Species of the World, Jean Lamprell, Brisbane, Australia, 2006). Most Spondylus pearls examined by GIA are reportedly from Spondylus princeps, whose bodycolor is typically white to cream or various saturations of pink, orange, and brown. This is the first time GIA has examined pearls with such a dominant purple hue reported to be from Spondylus calcifer. This species has been recorded as producing pearls in Costa Rica (E. Strack, Pearls, Ruhle-Diebener-Verlag GmbH & Co., Stuttgart, 2006, p. 59). @chapter:11 @chapter:4 @chapter:11


# Publication Year: -
# Title: At the Spring Auctions: A Spending Spree for the Ultra-Wealthy
# Abstract: The 100.09 ct Vivid yellow from Laurence Graff brought $16.3 million at Sotheby’s Geneva sale in May 2014, the most expensive yellow diamond ever sold at auction. Photo courtesy of Sotheby’s

	The world’s ultra-wealthy open their wallets even wider for the rare and fine in the first half of 2014. A Modigliani portrait sold for a record $18.4 million at Sotheby’s Paris auction in June, and a collection of wines went for $13 million at a Sotheby’s Hong Kong auction in April.

	It’s no surprise that unheard-of auction records for diamonds and colored gems followed suit. Indeed, it’s fitting that the spring 2014 season also broke the record for a jewelry auction’s shortest stay at the top: less than 24 hours.

	Economists note that the world’s wealthy have been putting more and more of their excess funds into such items and it’s buoyed the auctions’ bottom lines. Christie’s overall sales, with art leading the way, increased 27% for the first five months of the year, according to François Curiel, president of Christie’s Asia. Christie’s jewelry sales of $360 million were up 22% from the same period last year, doubling those of five years ago.

	“The jewelry and fine art markets are expanding, attracting more buyers than ever before,” said Curiel. He added that 30% of Christie’s buyers this season were new, coming from all parts of the world.

	Here is a roundup of this past season’s gem and jewelry sales.

Single-Auction Sales
	Sotheby’s Magnificent Jewels sale on May 13 in Geneva realized $141.5 million, the highest ever at a single jewelry auction. That total surpassed the previous mark, Christie’s December 2011 Elizabeth Taylor auction, by more than $25 million. The following day, however, Christie’s regained the title with a Geneva jewelry auction that took in $154.2 million.

Individual Gems
	Not surprisingly, a number of other records fell during these sales. The records came in a variety of colors.

Yellow Diamond: At the Sotheby’s auction, a 100.09 carat (ct) GIA-graded Fancy Vivid yellow from London jeweler Laurence Graff sold for $16.3 million, the highest price ever paid for a yellow diamond. This gem was one of the final stones polished by master diamond cutter Antonio Bianco, who died in 2009.

Colorless Diamond: Moments before the Graff yellow diamond came up, an anonymous bidder paid a record per-carat price of $246,710 for a colorless diamond: a GIA-graded 25.32 ct type IIa D-color internally flawless diamond.

Blue Diamond: At Christie’s May 14 Geneva auction, the top lot was the Winston Blue, a 13.22 ct pear-shaped Fancy Vivid blue flawless diamond that brought the highest per-carat price ever paid for a stone of that color and clarity. The buyer, Harry Winston Corp., paid $23.8 million ($1.8 million per carat). GIA noted it was the largest flawless Fancy Vivid blue diamond it had ever graded.

Green Diamond: At the same Christie’s sale, a 5.5 ct. Fancy Vivid blue-green diamond, the Ocean Dream, achieved a record price of $8.63 million for a diamond of that color.

Natural Pearls: At William Doyle Galleries in New York on April 30, a bidder paid a record $3.3 million for a pair of natural pearl drop earrings thought to have once belonged to Empress Eugénie of France. They are believed to have been part of the French crown jewels sold off in 1887, seventeen years after the fall of Napoleon III. The previous high was for a pair of natural pearls owned by actress Gina Lollobrigida, which sold in May 2013 for $2.4 million.

	The 5.5 ct Ocean Dream, left, a Fancy Vivid blue-green diamond, sold for $1.4 million per carat, a record for a diamond of that color. The 13.22 ct Winston Blue, right, graded by GIA, sold for $1.8 million per carat, the highest price ever paid for a Fancy Vivid blue diamond of flawless clarity. (Photos not to scale.) Photos courtesy of Christie’s

Overall Auction Prices Remain Strong
	Beyond these records, prices were generally strong across the board for colored gems and signed jewelry pieces from the world’s top jewelry houses.

	Christie’s May 28 Hong Kong sale brought in $91 million. Some of the highlights were:

		Jadeite bangle—$5.2 million

		Burmese ruby bracelet—$4.8 million

		A 6.18 ct. Fancy Intense green diamond—$3.6 million ($594,510 per carat)

	The sale also featured a number of large D-color flawless and internally flawless diamonds ranging from $188,000 to $191,000 per carat. Christie’s ended its season with a $27.5 million sale in New York, which included a 5.5 ct. GIA-graded Fancy Vivid pink diamond that accounted for more than one-third of that total—$9.6 million.

	Not everything sold. The 31.34 ct Victory diamond, found in Africa in 1945 and formerly part of the Florence Gould estate, failed to reach its presale estimate of $5–$8 million at Sotheby’s Geneva May 13–14. Likewise, a necklace featuring the 40.05 ct type IIa D-flawless diamond called the “Eye of Golconda” did not reach its estimate of $8.5 million at Christie’s May 28 Hong Kong sale.

	With the uneven economic recovery, these well-publicized auctions have not had the coattail effect seen in the past. The 1987 Jewels of the Duchess of Windsor sale, for example, “got the world emotionally involved in jewelry,” said one jewelry dealer, with an appropriately sharp upturn in demand for gems across the board. This time, sales of more mundane-sized diamonds and jewelry have not seen a surge in prices or sales growth at retail stores around the world.

	Still, these impressive auction prices have increased popular awareness of fancy-color diamonds and added to the mystique and allure of gemstones. That could serve the entire industry well as the world economy achieves a more secure footing.

	This set of natural drop pearls, believed to have once-belonged to Empress Eugénie of France, achieved a record $3.3 million at William Doyle Galleries’ April auction in New York. Photo courtesy of William Doyle Galleries @chapter:32 @chapter:3 @chapter:32


# Publication Year: 1993
# Title: Summer 1993 Gem News International
# Abstract: Diamonds
            Botswana Produces Large Diamond
            DeBeers Now Marketing High-Quality, High-Pressure Synthetic Diamond Products
            DeBeers Offers CVD Industrial Synthetic Diamond Products
            "Flanders Brilliant" Cut Debuts in U.S.
            Sakha (Yakutia) Building up Diamond Reserves
            Venezuela Diamond Production Up
Colored Stones
            Blue Cancrinite from Greenland
            "Emerald Matrix" from North Carolina
            Gemstone Globe and Maps
            Lapidary Art
            Banded Iridescent Obsidian
            Gems from Orissa, India
            Cultured Freshwater Pearls from Hanoi, Vietnam
            Peridot from Zabargad Island
            Ornamental Porphyry from Canada
            Natural Resin from Colombia
            Ruby Mining near Mahenge, Tanzania
Enhancements
            Opticon Follow-Up
            Turquoise Treatment Stability
Synthetics and Simulants
            Synthetic Corundum as a Topaz Simulant
            Russian Flux-Grown Synthetic Emeralds
            Novel Opal Simulants
            More on Plastic Imitation Opal
            ''Synthetic Opal" from Russia
            More on Paraiba Tourmaline Simulants
            Color-Zoned Synthetic Blue Quartz
            Nontransparent Synthetic Quartz
            Synthetic Spinel from Eastern Germany
Announcements
            New Exhibit at the Royal Ontario Museum

To view the full section, download the PDF above. @chapter:27 @chapter:1 @chapter:27


# Publication Year: 2019
# Title: Iridescent Tabasco Geode
# Abstract: Figure 1. This unique Tabasco geode from Mexico’s Zacatecas State, containing greenish blue botryoidal chalcedony, measures 24 mm in the longest dimension. Photo by Diego Sanchez; courtesy of Marquez Mining.
Tabasco geodes are a small geode variety named for the area where they are mined in the Mexican state of Zacatecas, near the city of Tabasco. Typically, these geodes are lined with water-clear drusy quartz, but the author recently examined one that was filled with greenish blue botryoidal chalcedony that also showed iridescent colors (figure 1). The cause of the colors was not immediately apparent, but microscopic examination revealed clues. The outermost layer of chalcedony had not firmly adhered to the underlying botryoidal mass. This delamination allowed an air gap along the interface of the thin outermost layer of chalcedony and the botryoidal mass of greenish blue chalcedony underneath. This air gap, in addition to the transparent nature of the very thin chalcedony shell, created thin-film interference colors along the interface of the chalcedony shell and substrate (figure 2). This explanation was supported by the observation that where areas of the delicate shell were damaged, the iridescence was not present. This Tabasco geode is one of the most visually interesting geodes examined by the author.

Figure 2. The Tabasco geode hosts greenish blue chalcedony, with a thin chalcedony shell that was responsible for the iridescent thin-film interference colors. Photomicrograph by Nathan Renfro; field of view 1.83 mm. @chapter:8 @chapter:0 @chapter:8


# Publication Year: 2018
# Title: Diamond Geology
# Abstract: Figure 1. Left: The stone’s FTIR spectrum revealed that it is a type Ib-IaA diamond with nitrogen defects, “C” single nitrogen atoms and an “A” pair of nitrogen atoms. Right: DiamondView images show cuboctahedral growth structure containing a {100} sector with reddish orange fluorescence and a {111} sector with green fluorescence. Distinct fluorescence zoning following growth structure is caused by NV centers in {100} sectors and H3 defects in {111} sectors, which were created during the irradiation and annealing processes.
Type Ib–Dominant Mixed-Type Diamond with Cuboctahedral Growth Structure: A Rare Diamond Formation
Kyaw Soe Moe and Paul Johnson
GIA, New York
Type Ib–dominant mixed-type diamonds (Ib-IaA) can be formed by multiple growth events (Titkov et al., 2015; Smit et al., 2018). In this study, we report on a 0.41 ct Fancy Dark brown gemquality diamond that formed in a single growth event. It is a type Ib-IaA with a C defect (single-substitutional nitrogen atom) concentration up to 21 ppm. The Fourier-transform infrared (FTIR) peaks of the H1a and H1b defects (figure 1, left) suggest that this diamond was irradiated and annealed to achieve a Fancy color grade. The cuboctahedral structure can be observed in the DiamondView images (figure 1, right), which show reddish orange fluorescence in the {100} sector caused by NV centers and green fluorescence in the {111} sector caused by H3 defects. Irradiation treatment helps us to see the cuboctahedral structure. However, the presence of an amber center suggests that it did not undergo HPHT treatment.
Cuboctahedral growth structure can be usually observed in HPHT diamonds that are grown in a laboratory with a fast growth rate (i.e., less than one week per carat) under P-T conditions of 5–6 GPa and 1300–1500°C. A natural diamond that grows rapidly in a single growth event would also possess mixed cuboid and octahedral forms.
Time and temperature are critical in the aggregation of nitrogen atoms in diamond. Nitrogen atoms are initially incorporated as single atoms during diamond formation. Our sample was rich in C defects associated with A defects (a pair of nitrogen atoms). This suggests that the process of nitrogen aggregation was interrupted by the diamond’s ascent to shallower depths in the mantle at lower temperatures by rapid tectonic exhumation (Smit et al., 2018). The cuboctahedral growth structure of this diamond indicated that, prior to ascending to shallower depths of the mantle, it grew in a few days in the diamond stability field (i.e., 150–200 km in depth within the earth) in a single growth event.
REFERENCES
Smit K.V., D’Haenens-Johansson U.F.S., Howell D., Loudin L.C., Wang W. (2018) Deformation-related spectroscopic features in natural type Ib-IaA diamonds from Zimmi (West African craton). Mineralogy and Petrology, pp. 1–15, http://dx.doi.org/10.1007/s00710-018-0587-6

Titkov S.V., Shiryaev A.A., Zudina N.N., Zudin N.G., Solodova Y.P. (2015) Defects in cubic diamonds from the placers in the northeastern Siberian platform: Results of IR microspectrometry. Russian Geology and Geophysics, Vol. 56, No. 1-2, pp. 354–362, http://dx.doi.org/10.1016/j.rgg.2015.01.026
Evidence of Subducted Altered Oceanic Crust into Deep Mantle from Inclusions of Type IaB Diamonds
Tingting Gu1, John Valley2, Kouki Kitajima2, Michael Spicuzza2, John Fournelle2, Richard Stern3, Hiroaki Ohfuji4, and Wuyi Wang1
1GIA, New York
2Department of Geoscience, University of Wisconsin, Madison
3Canadian Centre for Isotopic Microanalysis (CCIM), Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton
4Geodynamics Research Center (GRC), Ehime University, Matsuyama, Japan
Nitrogen is one of the most common impurities in diamond, and its aggregation styles have been used as criteria for diamond classification. Pure type IaB diamonds (with 100% nitrogen in B aggregation) are rather rare among natural diamonds. The occurrence of the B center is generally associated with high temperature and a long residence time of the host diamond, which would potentially provide information on the earth’s deep interior. Seawater circulation is the unique process that shapes the surface of our planet and potentially has a profound effect on its interior due to slab subduction.
In about 50 type IaB diamonds with detectable micro-inclusions submitted to GIA for screening, we found that more than 70% of them contained a typical mineral assemblage from the sublithosphere. Jeffbenite (TAPP), majorite garnet, enstatite, and ferropericlase have been observed, which could be retrograde products of former bridgmanite. CaSiO3-walstromite with larnite and titanite is the dominant phase present in approximately 40% of all diamond samples. Direct evidence from oxygen isotope ratios measured by secondary ion mass spectrometry, or SIMS, (δ18OVSMOW in the range +10.7 to +12.5‰) of CaSiO3-walstromite with coexisting larnite and titanite that retrograde from CaSiO3-perovskite suggest that hydrothermally altered oceanic basalt can subduct to depths of >410 km in the transition zone. Incorporation of materials from subducted altered oceanic crust into the deep mantle produced diamond inclusions that have both lower mantle and subduction signatures. Ca(Si,Al)O3-perovskite was observed with a high concentration of rare earth elements (>5 wt.%) that could be enriched under P-T conditions in the lower mantle. Evidence from ringwoodite with a hydroxide bond, coexisting tuite and apatite, precipitates of an NH3 phase, and cohenite with trace amounts of Cl imply that the subducted brines can potentially introduce hydrous fluid to the bottom of the transition zone. In the diamonds with subducted materials, the increasing carbon isotope ratio from the core to the rim region detected by SIMS (δ13C from –5.5‰ to –4‰) suggests that an oxidized carbonate-dominated fluid was associated with recycling of the subducted hydrous material. The deep subduction played an important role in balancing redox exchange with the reduced lower mantle indicated by precipitated iron nanoparticles and coexisting hydrocarbons and carbonate phases.
Origin of Rare Fancy Yellow Diamonds from Zimmi (West Africa)
Karen V. Smit1, Ulrika F.S. D’Haenens-Johansson1, Daniel Howell2, Lorne C. Loudin1, and Wuyi Wang1
1GIA, New York
2Department of Geoscience, University of Padua, Italy, and Diamond Durability Laboratory, New York
Type Ib diamonds from Zimmi, Sierra Leone, have 500 My mantle residency times whose origin is best explained by rapid tectonic exhumation after continental collision to shallower depths in the mantle prior to kimberlite eruption (Smit et al., 2016). Here we present spectroscopic data for a new suite of Zimmi sulfide-bearing type Ib diamonds that allow us to evaluate the link between their rare Fancy yellow colors, the distribution of their spectroscopic features, and their unusual geological history. Cathodoluminesence (CL) imaging revealed irregular patterns with abundant deformation lamellae, associated with the diamonds’ tectonic exhumation (Smit et al., 2018). Vacancies formed during deformation were subsequently naturally annealed to form vacancy clusters, NV0/− centers, and H3 (NVN0). The brownish yellow to greenish yellow colors observed in Zimmi type Ib diamonds result from visible absorption by a combination of isolated nitrogen and deformation-related vacancy clusters (Smit et al., 2018). Color-forming centers and other spectroscopic features can all be attributed to the unique geological history of Zimmi type Ib diamonds and their rapid exhumation after formation.
REFERENCES
Smit K.V., Shirey S.B., Wang W. (2016) Type Ib diamond formation and preservation in the West African lithospheric mantle: Re-Os age constraints from sulphide inclusions in Zimmi diamonds. Precambrian Research, Vol. 286, pp. 152–166, http://dx.doi.org/10.1016/j.precamres.2016.09.022

Smit K.V., D’Haenens-Johansson U.F.S., Howell D., Loudin L.C., Wang W. (2018) Deformation-related spectroscopic features in natural type Ib-IaA diamonds from Zimmi (West African craton). Mineralogy and Petrology, pp. 1–15, http://dx.doi.org/10.1007/s00710-018-0587-6 @chapter:22 @chapter:1 @chapter:22


# Publication Year: -
# Title: Gem-Carved Ensemble is Music to Philanthropist’s Ears
# Abstract: View Gallery

	“Symphony in Gemstones,” a miniature, 21-piece orchestra carved of gem materials, was donated to the GIA Museum Collection by Art Sexauer, a longtime benefactor of the museum, in 2002.

	Each instrument offers its own special characteristics, from the tourmaline violins and Persian turquoise trumpet to a lapis saxophone and a spectacular tiger-eye harp with 14K gold strings. The collection’s rhythm section is rounded out by three kettledrums made of black onyx and quartz and a grand piano that features a white quartz and black onyx keyboard

	Sexauer’s idea for the “Symphony in Gemstones” came from a visit to the Tucson Gem and Mineral shows in in the early 1980s when he came across a crude gem carving of a guitar. He was instantly inspired to create an entire gemstone orchestra carved by the expert hands of German artisans in Idar-Oberstein.

	Sexauer, who had already amassed an exceptional collection of tourmaline animal carvings, was well aware of the time and dedication assembling a miniature orchestra carved from gem materials would take. He commissioned master carver Lothar Herrmann and his partner David Hudson, who took one year to create the set, which is displayed on a three-tiered, white marble stage.

	“Symphony in Gemstones” has been on display several times at the Tucson Gem and Mineral shows, as well as in museums across the United States. Sexauer believes the collection may be the only one of its kind in the world.

	Sexauer, who’s had an appreciation for music since his childhood when he would listen to his father play the violin, says the symphony represents two of his favorite things.

	“Music is beautiful and gemstones are beautiful,” he says. “If you put the two together the combination must surely be magnificent.” @chapter:28 @chapter:2 @chapter:28


# Publication Year: 1996
# Title: A History of Diamond Sources in Africa: Part II
# Abstract: Following the history of diamond discoveries in southern Africa presented in Part I, this article discusses the history of diamond exploration and mining in East and West Africa. The first economic kimberlite outside South Africa was discovered in Tanzania (East Africa) in 1940, and major quantities of large, high-quality alluvial diamonds have been mined in West Africa since the mid-1930s. Early miners struggled with misconceptions about how diamonds formed and concerns as to the depth to which diamonds could occur in pipes. Mining developments and new diamond occurrences in Africa led to many of the key concepts in modern diamond geology. Although Africa's long dominance in world diamond production has diminished in recent decades, its steady output and large reserves ensure its continuing role as the most important diamond-producing region in the world, surpassing in overall impact even Australia and Russia. @chapter:21 @chapter:1 @chapter:21