Title: Tourmaline Inclusion with Included Crystals in Kashmir Sapphire Abstract: This tourmaline inclusion in a 1.81 ct Kashmir sapphire contains a few unusual “daughter” crystals with rounded edges. Photomicrograph by Yusuke Katsurada; field of view 0.73 mm.
The authors recently examined a 1.81 ct blue cushion mixed cut identified as sapphire. Microscopic examination showed sharp-banded milky clouds, particle stringers, and a well-formed euhedral greenish crystal. The crystal displayed a triangular prismatic habit with sharp basal pinacoids. This is typical of tourmaline, and the inclusion’s identity was later confirmed by Raman spectroscopy.
Tourmaline inclusions in sapphire are diagnostic of a Kashmir origin (see R. Schwieger, “Diagnostic features and heat treatment of Kashmir sapphires,” Winter 1990 G&G, pp. 267–280). Trace element analysis with laser ablation–inductively coupled plasma–mass spectrometry supported the microscopic observations, revealing a chemistry consistent with classic Kashmir samples from GIA’s colored stone reference collection.
Interestingly, the tourmaline possessed uneven rounded inclusions of its own (see above). These crystals were presumably a different material, given their lighter tone and sharp boundaries, which contrasted with the tourmaline host. Unfortunately, they could not be identified with Raman spectroscopy, leaving us to speculate about their true nature. Source: GIA @topic:2


Title: Ancient Script-Like Serpentine in Brown Peridot Abstract: Thread-like inclusions of serpentine resembling an ancient text. Photomicrograph by Le Ngoc Nang; field of view 2.50 mm.
Peridot is a green olivine often characterized by “lily pad” inclusions and high birefringence causing a doubling effect. Apart from its familiar green hue, peridot can also possess a brown color, though these gems receive little attention.
Recently, the author found a xenocryst of peridot from southeast Vietnam that appeared black in daylight and brown through a transmitted light source. Standard gemological testing of a cabochon (2.51 ct) and two faceted stones (2.35 and 4.65 ct) that were cut from this xenocryst indicated peridot, but the specific gravity and refractive index gave higher results than the values for green peridot. Finally, the Raman spectra confirmed the identification as peridot.
Microscopic examination did not reveal any typical “lily pad” inclusions. Instead, there were innumerable fascinating thread-like inclusions (see above). Some formed closed loops with round, oval, and distorted shapes measuring from a few nanometers to a millimeter. Others stretched or twisted together like tangled threads up to 2 mm long. The display was reminiscent of an ancient script. Micro-Raman spectral analysis revealed these thread-like inclusions were serpentine.
Examination of this brown peridot revealed an unexpected inclusion scene quite different from the common inclusions found in green peridot. Source: GIA @topic:1


Title: Curved Banding in Flame-Fusion Synthetic Sapphires Abstract: Figure 1. Curved banding is easily spotted in this flame-fusion blue synthetic sapphire when illuminated with the Magilabs deep-UV fluorescence system, a short-wave UV source. Photomicrograph by E. Billie Hughes; field of view ~13 mm.

Most synthetic ruby and sapphire on the market is grown by Verneuil flame fusion. It can usually be separated from natural corundum by its distinctive curved banding, in contrast to the angular zoning seen in natural stones. Gemologists may see these features in the microscope when using darkfield or brightfield illumination. This zoning can also be seen with use of a short-wave fluorescent light, as noted in Ruby & Sapphire: A Gemologist’s Guide (R.W. Hughes et al., Lotus Publishing, Bangkok, 2017).

Figure 2. Observed with a short-wave UV light source, the sample displays curved banding, a telltale sign of a flame-fusion synthetic sapphire. Photomicrograph by E. Billie Hughes; field of view ~24.5 mm.
Recently the author noticed two excellent examples. When viewed with the Magilabs deep-UV fluorescence system (a proprietary short-wave UV source), the curved banding in the synthetics was clear (figures 1 and 2), allowing them to be easily separated from natural corundum. Gemologists using a DiamondView may see the same reaction. Source: GIA @topic:3


Title: Grandidierite Inclusions in Sapphires Abstract: Figure 1. Lath-like mineral inclusions of grandidierite were seen in this sapphire at GIA’s Carlsbad laboratory. Photomicrograph by Nathan Renfro; field of view 2.61 mm.

Recently the authors independently encountered an inclusion that has not been previously reported in sapphire. Both stones contained colorless crystals that were identified by Raman analysis as the mineral grandidierite. The sapphire examined by author MH in Carlsbad, California, contained colorless lath-like inclusions (figure 1). The sapphire examined by author EBH in Bangkok contained a colorless crystal that reached the surface of the sapphire host and displayed a duller luster in reflected light, and birefringent interference colors when examined using cross-polarized light (figure 2). Both observations are consistent with what one would expect for grandidierite.

Figure 2. A colorless grandidierite crystal was seen in a sapphire examined by author EBH at Lotus Gemology in Bangkok (left). In reflected light, the grandidierite inclusion showed a duller luster than the sapphire host (center) and cross-polarized light revealed birefringent interference colors (right). Photomicrographs by E. Billie Hughes; field of view 1.7 mm.
Grandidierite, named after French naturalist Alfred Grandidier (1836–1921), is an extremely rare orthorhombic Mg-Fe aluminous borosilicate with the formula (Mg,Fe)Al3(BO3)(SiO4)O2. The mineral is described as bluish green to greenish blue; the blue color increases with Fe content. It is transparent to translucent with a pale yellow to colorless, greenish blue, and blue trichroism. Since its discovery, grandidierite has been found as a rare accessory mineral in aluminous boron-rich pegmatite; in aplite, gneiss, and crystalline rock associated with charnockite; and in rock subjected to local high-temperature, low-pressure metamorphism (contact aureoles and xenoliths). To the authors’ knowledge, these are the first observations of grandidierite as an inclusion in sapphire. Source: GIA @topic:2


Title: Microlite Crystals in Topaz from Pakistan Abstract: Figure 1. A 16 mm topaz crystal and an 8.69 ct faceted topaz, both with microlite inclusions, from Pakistan. Photo by J. Hyršl.

Microlite, NaCaTa2O6(OH), is a typical mineral of highly developed lithium pegmatites, known from many localities worldwide. It always forms yellow to orange octahedral crystals. It was already known as inclusions in quartz from Pakistan (J. Hyršl and G. Niedermayr, “Einschlüsse im ‘Allerweltsmineral’ quarz,” Mineralien-Welt, Vol. 18, No. 2, 2007, pp. 44–55), but much more beautiful are microlite inclusions in topaz (figure 1), examples of which were sold in Tucson in January 2018. Shigar Valley in northern Pakistan was reported as the locality. Both minerals were confirmed by Raman spectroscopy.
Topaz forms loose, very light brown crystals up to about 2 cm, and microlite forms sharp transparent orange octahedrons in sizes up to about 1.5 mm. The inclusions grew both on the surface and inside the topaz crystals (figure 2). Several topaz crystals were faceted, and the stones host some of the most aesthetically pleasing inclusions found during the several last years.

Figure 2. A microlite crystal, measuring 1 mm across, in a topaz from Pakistan. Photo by J. Hyršl. Source: GIA @topic:2


Title: Staurolite in a Mozambique Ruby Abstract: Orangy red staurolite crystals surround a negative crystal in a Mozambique ruby. Planes of thin films can be seen behind them. Photomicrograph by Nicole Ahline; field of view 1.42 mm.

Rubies from Mozambique have a well-known inclusion suite that can consist of particle clouds, planes of platelets, and negative crystals as well as sulfite and amphibole crystals. These inclusions and their trace element chemistry make the geographical origin of Mozambique rubies less difficult to decipher. Recently, a 1.11 ct unheated ruby was examined by the author for identification. Internally there were scattered silk with planes of thin films as well as negative crystals. These inclusions plus trace element chemistry collected by laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) analyses confirmed the stone to be from Mozambique.
Mozambique rubies have a consistent suite of inclusions, and noting something out of the ordinary is quite uncommon. Alongside the negative crystals were clusters of a transparent orangy red crystal that the author had no prior knowledge of seeing in a Mozambique ruby (see above). Raman spectroscopy identified the unknown crystals as staurolite, a nesosilicate mineral known to occur in Mozambique. In a recent issue of G&G, staurolite was examined and documented for the first time as an inclusion in corundum, specifically in a Madagascar ruby (Spring 2020 Micro-World, pp. 144–145). The author believes that this staurolite is the first of its kind documented in a Mozambique ruby. Inclusions such as these will forever keep gemologists on the lookout for the next unknown. Source: GIA @topic:1


Title: Large Faceted Gahnospinel Abstract: This 11.34 ct gahnospinel was the largest identified by GIA. Photo by Diego Sanchez.

Gahnospinel is a rare dark greenish blue gemstone that belongs to the spinel group. Its properties result from being part of a solid solution series with the end members gahnite (ZnAl2O4) and spinel (MgAl2O4). Because of the high amount of zinc in the mineral, the refractive index (RI) and specific gravity (SG) shift from lower values for the spinel end member to higher values as the amount of Zn substituting for Mg increases, which may lead to confusion when trying to identify it. Spinel has an SG of 3.06 and an RI of 1.718, while gahnite has an SG of 4.55 and an RI of 1.800. As a combination of the two, gahnospinel’s SG can fall anywhere in between.
An 11.34 ct transparent faceted oval mixed cut (see above) was recently submitted to the Carlsbad lab for an identification report. Despite the stone’s large size, the only inclusions were tiny crystals. To date, this is the largest gahnospinel seen at any GIA laboratory worldwide. The previous stones submitted were 1.95 ct and below. Standard gemological testing revealed an RI of 1.754 and an SG of 4.10. These results are not typical for spinel. Inductively coupled plasma–mass spectrometry (ICP-MS) data revealed a very high zinc content and the stoichiometry of the sample was calculated to be the following: (Mg0.485Zn0.385Fe2+0.043)0.913(Al2.049Si0.004)2.053O4. The atomic mass of zinc is 65.38, far greater than the 24.31 atomic mass of Mg. As the amount of zinc substitution for Mg in gahnospinel increases, it tends to have a higher RI and specific gravity than spinel. This variety of spinel may bring identification challenges without advanced testing techniques to identify the presence of Zn. Source: GIA @topic:2


Title: Purple Fluorite Inclusion in Emerald from Russia Abstract: A Russian emerald hosts a crystal inclusion—identified by laser Raman microspectrometry analysis as fluorite—that exhibits a distinct purple color. Photomicrograph by Jonathan Muyal; field of view 1.44 mm.

Fluorite inclusions in emeralds from various localities have been reported extensively in the literature. They have been described as “whitish-colorless, octahedral-cube and/or corroded rounded shapes” (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Vol. 3, Opinio Publishers, Basel, Switzerland, 2008). However, purple fluorite in an emerald host is rare.
Author CM previously documented a purple banded fluorite inclusion in an emerald submitted to GIA for identification (Fall 2016 Lab Notes, pp. 302–303). This was noted as “an interesting and unexpected addition to an otherwise typical (emerald) inclusion scene.” Surprisingly, the current authors recently found another purple fluorite inclusion in an emerald (see above) from GIA’s research reference collection. Purchased from Alexey Burlakov (Tsarina Jewels, JTC, Bangkok), it was reportedly from the Malysheva mine, located a few kilometers northeast of Yekaterinburg, Russia.
Closer examination of the inclusion revealed a large, distinct purple zone, as well as a purple band and a subhedral crystal form. The inclusion proved to be singly refractive when viewed between crossed polarizers. Laser Raman microspectrometry confirmed that the inclusion was fluorite. Trace-element chemistry of the host emerald collected via laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) matched well with GIA’s Russian emerald chemistry reference data.
Raman analysis and microscopic observation conclusively identified the inclusion as fluorite. This strongly suggests that the unusual purple inclusion observed by author CM in 2016 was indeed fluorite; in that case, the inclusion was too deep in the stone to analyze with Raman. It is possible that purple fluorite is an unusual internal feature found only in Russian emerald, since that is the only known source from which we have observed this inclusion. Source: GIA @topic:2


Title: Euhedral Phantom Sapphire in Sapphire Abstract: Figure 1. A partially tapered bipyramid sapphire inclusion within a sapphire. Photomicrograph by Britni LeCroy; field of view 2.90 mm.

A phantom sapphire crystal within a host sapphire crystal was recently examined at GIA’s Carlsbad laboratory. The inclusion showed euhedral morphology as one half of a partially tapered bipyramid. The visible boundaries of the included crystal were composed of unaltered fingerprints with geometric patterns and fine linear rows. The crystal’s surface also showed moderate-order birefringence colors; these represented the shared interface between the host’s crystal lattice and the inclusion’s crystal lattice (figure 1). External local fingerprints also terminated around the crystal’s end point. Negative crystals within the inclusion showed tabular hexagonal habit (figure 2, left). When the host sapphire was exposed to temperatures below the freezing point of water, a CO2 bubble was seen within the largest negative crystal (figure 2, right). A sapphire with this inclusion combination is rarely seen.

Figure 2. Left: Negative crystals with tabular hexagonal habit within a euhedral sapphire inclusion. Right: A CO2 bubble appears within the largest negative crystal (see arrow) after the stone was exposed to temperatures below the freezing point of water. Photomicrographs by Britni LeCroy; field of view 1.76 mm. Source: GIA @topic:3


Title: Wollastonite in Devitrified Glass Imitating Horsetail Inclusions in Demantoid Garnet Abstract: Figure 1. A yellowish green glass with numerous wollastonite needles radiating from the center, similar to the horsetail inclusions found in demantoid garnets. Photomicrograph by Ungkhana Atikarnsakul; field of view 14.4 mm.

A 13.12 ct transparent yellowish green gemstone with a beautiful internal scene was examined by the author. The specimen exhibited numerous elongated colorless crystals radiating from the center (figure 1), much like the horsetail inclusions of chrysotile that one would expect to find in Russian demantoid garnets. Standard gemological testing yielded surprising results: a single refractive index of 1.520, specific gravity of 2.50, and medium chalky green fluorescence under short-wave UV light. The specimen was inert to long-wave UV light. These properties indicated that the yellowish green cabochon stone was glass, whereas the masses of needle-like crystals (figure 2) were identified as calcium silicate wollastonite by Raman spectroscopy. Wollastonite inclusions have been reported as an indicator of the devitrification process (Winter 2017 Micro-World, pp. 469–470).

Figure 2. Close-up view of the wollastonite crystals. Photomicrograph by Ungkhana Atikarnsakul; field of view 4.8 mm.
Other advanced techniques, including energy-dispersive X-ray fluorescence (EDXRF) and Fourier-transform infrared (FTIR) and Raman spectroscopy, were also carried out to confirm the cabochon’s identity. FTIR and Raman spectroscopy showed a distinct and characteristic pattern of artificial glass. The nonquantitative EDXRF offers no additional value, as the elements detected are also present in demantoid garnets.
Although this is not the first time that wollastonite inclusions have been found in devitrified glasses, they formed in an interesting pattern in this yellowish green gemstone. Source: GIA @topic:2


Title: Aquamarine with Zigzag Growth Line Inclusions Abstract: Figure 1. A 55 ct cushion-cut aquamarine exhibiting a distinct light bluish green and deep blue pleochroism using a dichroscope. Photos by Kaiyin Deng; courtesy of Farrugia Gem.

Figure 2. Infrared transmission spectra (left) and UV-Vis-NIR spectrum (right) of the aquamarine sample. The spectra on the left are offset vertically for clarity.
A 55 ct cushion-cut aquamarine (figure 1, left) was recently submitted to Guild Gem Laboratories in Shenzhen for testing. This stone exhibited a very intense blue color accompanied by a subtle greenish secondary hue. A refractive index of 1.580–1.586 was obtained, together with a specific gravity of approximately of 2.71. Fourier-transform infrared (FTIR) and Raman spectroscopy confirmed its identity as beryl. The transmission FTIR spectrum exhibited distinct peaks at 2731, 2686, and 2641 cm–1 and a carbon dioxide–related signal at 2359 cm–1. Peaks at 3235, 3162, 3111, and 3021 cm–1 were assigned to the presence of water (figure 2, left). This collection of FTIR peaks has been reported in natural aquamarine, but no synthetic counterpart has been reported to show this pattern (I. Adamo et al., “Aquamarine, Maxixe-type beryl, and hydrothermal synthetic blue beryl: Analysis and identification,” Fall 2008 G&G, pp. 214–226). No organic-related peaks were found around the 2800–3200 cm–1 range, suggesting no clarity enhancement had been applied (L. Jianjun et al., “Polymer-filled aquamarine,” Fall 2009 G&G, pp. 197–199). Strong deep blue and light bluish green pleochroism (figure 1) was observed using a dichroscope. Similar beryl materials with a deep blue color have been reported in previous studies (Fall 2014 GNI, pp. 244–245; Fall 2019 GNI, pp. 437–439). The ultraviolet/visible/near-infrared spectrum (figure 2, right) showed a broad Fe2+-related band centered at around 835 nm and narrow absorption bands at 370 and 426 nm related to Fe3+ (D.S. Goldman et al., “Channel constituents in beryl,” Physics and Chemistry of Minerals, Vol. 3, No. 3, 1978, pp. 225–235; K. Schmetzer, “Hydrothermally grown synthetic aquamarine manufactured in Novosibirsk, USSR,” Fall 1990 G&G, pp. 206–211; Adamo et al., 2008). Using a polariscope equipped with a conoscope, the optic axis was observed parallel to the table along the long axis of the cushion shape. Further chemical analysis by energy-dispersive X-ray fluorescence showed a high iron content (around 13000 ppmw), which likely contributed to the saturated blue color (Y. Shang et al., “Spectroscopy and chromaticity characterization of yellow to light-blue iron-containing beryl,” Scientific Reports, Vol. 12, No. 1, 2022, article no. 10765).

Figure 3. The thin film along the basal plane of the aquamarine under fiber-optic illumination. Photomicrographs by Yizhi Zhao; fields of view 3.45 mm (left) and 1.72 mm (right).
Microscopic observation under darkfield illumination revealed fluid inclusions and minute voids. Under the table, a circular thin film with a strong light reflection was visible (figure 3). The image in figure 3 (left) was captured at an angle to the table of the aquamarine, since the thin film was easier to see under an oblique light source. Because beryl has imperfect cleavage along its basal plane {0001}, the space between the basal planes caused by initial cleavage was sufficient to form the thin film.

Figure 4. Zigzag lines were observed in the aquamarine using oblique light. Photomicrograph by Yizhi Zhao; field of view 4.52 mm.
An interesting inclusion was observed only with oblique light: a distinct series of fluids resembling dots and broken lines. Higher magnification (figure 4) revealed that these zigzag lines consisted of discrete and minute fluid inclusions. Further observation along the optic axis confirmed that the planes were parallel to the c-axis of the aquamarine.
A previous study described similar inclusions in emeralds from Colombia as resembling a DNA double helix (Summer 2019 G&G Micro-World, p. 262). The authors have also encountered this type of inclusion before. Based on our observations, these helical inclusions spiral along the optic axis of the emerald. To our knowledge, this is the first time such helical inclusions have been reported in an aquamarine. This finding will help advance our understanding of the beryl family. Source: GIA @topic:3


Title: Cat’s-Eye Paraíba Tourmaline with Copper Inclusions Abstract: Figure 1. This 1.33 ct cat’s-eye Paraíba tourmaline with copper inclusions shows a golden chatoyancy. Photo by Shunsuke Nagai.
The Tokyo laboratory recently received a 1.33 ct greenish blue oval cabochon measuring 6.83 × 6.17 × 3.55 mm (figure 1) and displaying a cat’s-eye effect. Standard gemological testing yielded a refractive index of 1.620–1.640, a uniaxial optical sign, and a hydrostatic specific gravity of 3.08, all consistent with tourmaline. Ultraviolet/visible/near-infrared spectrometry showed the absorption band at 900 nm, which is greater than the one at 700 nm, indicating the greenish blue color of this sample was dominated by copper (P.B. Merkel and C.M. Breeding, “Spectral differentiation between copper and iron colorants in gem tourmaline,” Summer 2009 G&G, pp. 112–119). This stone meets the requirement for designation as a Paraíba tourmaline (Laboratory Manual Harmonisation Committee Information Sheet #6, 2012). Laser ablation–inductively coupled plasma–mass spectrometry indicated a high copper concentration of 11741–14794 ppmw. The high copper (over 10000 ppmw) is limited to Brazilian origin (Y. Katsurada et al., “Geographic origin determination of Paraíba tourmaline,” Winter 2019 G&G, pp. 648–659).
As previously reported (Winter 2018 Lab Notes, pp. 438–439), cat’s-eye Paraíba tourmaline usually includes groups of parallel tube-like inclusions that create the phenomenon. However, that was not the case for this tourmaline.

Figure 2. The copper inclusions on the lower right are partially reflecting light. Photomicrograph by Yuxiao Li; field of view 3.5 mm.
Different from normal cat’s-eye Paraíba tourmaline, the band of reflected light in this stone was stronger, with metallic luster. Microscopic examination revealed a fluid inclusion network, rounded metallic inclusions, and growth tubes, with many golden-colored dendritic inclusions causing the cat’s-eye effect (figures 2 and 3). Raman spectroscopy could not be used to identify the inclusions, which were too thin and did not reach the surface. Such inclusions in Paraíba tourmaline have been reported and identified as natural copper (F. Brandstätter and G. Niedermayr, “Copper and tenorite inclusions in cuprian-elbaite tourmaline from Paraíba, Brazil,” Fall 1994 G&G, pp. 178–183). The natural copper inclusions were aligned in the same direction, parallel to each other, and reflected the light to cause the chatoyant effect. This also explains why the reflective light band in this stone looked different from other cat’s-eye Paraíba tourmaline.

Figure 3. The copper inclusions aligned in the same direction appear brownish and black (left) and together display golden luster when the light enters from a certain direction (right). Photomicrographs by Yuxiao Li; field of view 2.3 mm.
While some cat’s-eye Paraíba tourmalines have been examined in GIA laboratories, this is the first with chatoyancy caused by copper inclusions. Source: GIA @topic:2


Title: Quarterly Crystal:Growth Features on Titanite Abstract: Figure 1. This beautifully formed 17.04 mm titanite
crystal from Russia owes its green color to the presence of vanadium. Photo by Kevin Schumacher.

	The micro-world of gems and minerals involves not only solid and fluid inclusions, but also significant surface features. If a gem crystal is fashioned into a gemstone by a lapidary artist, most of the surface features of any significance are removed during the process. So when we encounter a beautiful gem crystal, we always take the opportunity to examine the natural surfaces for any interesting evidence of growth or dissolution.

	In that regard, we recently studied a beautifully formed titanite crystal (figure 1) from the Ural Mountains in Russia that measured 17.04 × 15.27 × 0.94 mm and weighed 2.35 ct. EDXRF analysis confirmed that its bright green color resulted from the presence of vanadium. As shown in figure 2, examination of the surface using Nomarski differential interference contrast microscopy revealed an abundance of growth features, some with rather dramatic architecture. These were the features targeted for photomicrography.

	Figure 2. Some of the growth features observed on the surface of the titanite crystal were reminiscent of jagged mountain peaks. Photomicrograph by Nathan Renfro; field of view 0.72 mm. Source: GIA @topic:2


Title: Outlook on Opals from Mexico and Australia Abstract: Figure 1. Mexican fire opal is clear enough to be faceted, and ranges from colorless to dark red. Photo by Kevin Schumacher.

Emil Weis Opals (Idar-Oberstein, Germany) opened its doors in 1905, making it the oldest opal cutting company in the world. Idar-Oberstein was the only global gem cutting center at the time, and opal buyers from all major gem markets had to send rough there for cutting. Emil Weis catered to this niche market early on and has since branched into mining; the company now owns mines in Australia and Mexico. We sat down with Jürgen Schütz, part of the founding family at Emil Weis, to discuss their activities in the opal market.

Jürgen Schütz Reflects on the Opal Market
Jürgen Schütz discusses the demand and future potential for non-phenomenal and play-of-color opal.
Currently the company is cutting 50 different types of opal from all over the world, the majority of it from Australia and Mexico. Emil Weis sells more nonphenomenal opal from these countries than it does play-of-color opal. The Mexican boulder opals they had on display were such an example. These specimens are cut to include both opal and rhyolite matrix, which some jewelry designers like to use in their pieces. According to Schütz, the nonphenomenal “fire” opal from Mexico (figure 1) is the only opal mined in quantity that is clear enough for faceting. It ranges from colorless to a dark red that is comparable with ruby. This type of material is available in large quantities and can even be calibrated.

Figure 2. Jürgen Schütz discussed the current supply and demand dynamics of Australian black opal. Photo by Kevin Schumacher.
Schütz then discussed the shortage of and demand for Australian black opals (see figure 2). In the past, Japanese demand for black opals drove prices up, but when Japan’s economy slowed in the early 1990s, prices fell and production slowed. However, recent rumors that Chinese markets are interested in black opal have doubled prices. Schütz showed us a rare black opal suite from Lightning Ridge, Australia, which took years to collect. Emil Weis has had this suite for about 10 years; today, it would be impossible to assemble this combination of black opals due to low production.

Figure 3. According to Schütz, the lack of active miners along the Queensland opal belt has led to a shortage of Australian boulder opal. Photo by Kevin Schumacher.
Production of Australian boulder opal (figure 3) is quite low. This is partially due to weather conditions, but Schütz noted that the boulder opal belt of Queensland is about 3,000 km long and 800 km wide, with only about 25 people mining it. This means that medium- to high-quality material is not produced in quantity. Schütz himself has connections with some of the older Queensland miners who have held on to parcels. Over the past two years he has been able to buy a parcel at a time from them. As a result, Emil Weis has a huge stockpile of boulder opal to cut, but does so sparingly.

Schütz noted that the supply of South Australian light opals is also severely constrained. When Ethiopian opal came on the market at one-tenth of the price, the demand for Australian opal slowed. By the time buyers regained interest in South Australian opal, the mining population had dropped from several thousand to about 20 in less than a decade. In fact, Schütz said, Australian opal mining has traditionally been such a difficult way of life that many young people are opting for more stable jobs, leaving large gaps in the mining industry. He thinks that it may take another generation or two before mining once again hits its stride Down Under. Source: GIA @topic:11


Title: Red-Dyed Spodumene Imitating Ruby Abstract: Figure 1. A semitranslucent 5.72 ct red-dyed spodumene, presented as “red corundum.” Photo by Guy Borenstein.
A semitranslucent deep red oval faceted gem, measuring 13.88 × 9.08 × 5.88 mm and weighing 5.72 ct (figure 1), was recently submitted to Stuller Inc. by a client for a custom design. The stone was presented as “red corundum.” But initial quality control testing showed a biaxial refractive index of 1.659–1.678 with a birefringence of 0.019, which did not correspond with corundum.
Due to the incorrect identity, the stone was sent to Stuller’s gemological laboratory for further analysis. Standard gemological testing revealed a specific gravity of 3.237, with a moderate orange reaction to long-wave UV and a very weak reaction, along the fractures, to short-wave UV, typical of spodumene species. Further analysis, using a 532 nm Raman laser, also provided well-matched results for spodumene (LiAl(SiO3)2). Although the collected results clearly pointed to spodumene, the deep red color it displayed was questionable and required further investigation.

Figure 2. The unpolarized UV-Vis-NIR spectrum of the dyed spodumene shows a broad band centered at 561 nm due to the red dye. The band centered at 430 nm may be related to an intervalence charge transfer species between neighboring iron and manganese, while the band at 530 nm may be related to Mn3+.
Unpolarized ultraviolet/visible/near-infrared (UV-Vis-NIR) spectroscopy showed two merging broad bands centered at 530 and 561 nm (figure 2). The former is probably associated with the Mn3+ chromophore (H.U. Rehman et al., “An X-ray absorption near-edge structure (XANES) study on the oxidation state of chromophores in natural kunzite samples from Nuristan, Afghanistan,” Minerals, Vol. 10, No. 5, 2020, article no. 463), while the latter was previously reported as associated with red dyeing (K. Schmetzer et al., “Dyed natural corundum as a ruby imitation,” Summer 1992 G&G, pp. 112–115). A possibly iron- and manganese-related shoulder at 430 nm (R. Lu, “Color origin of lavender jadeite: An alternative approach,” Winter 2012 G&G, pp. 273–283) was also observed.

Figure 3. The FTIR spectrum of the dyed spodumene shows a series of peaks at 2954, 2924, 2872, and 2854 cm–1, associated with a typical universal paraffin oil.

Figure 4. Deep UV imaging of the spodumene’s surface showed strong luminescence of the dye within a cavity as well as surface-reaching fractures. Image by Guy Borenstein; field of view 6.25 mm.
Fourier-transform infrared (FTIR) spectroscopy revealed peaks at 2954, 2924, 2872, and 2854 cm–1 (figure 3), typical of a universal paraffin oil filler (M.L. Johnson et al., “On the identification of various emerald filling substances,” Summer 1999 G&G, pp. 82–107; L. Kiefert et al., “Identification of filler substances in emeralds by infrared and Raman spectroscopy,” Journal of Gemmology, Vol. 26, No. 8, 1999, pp. 501–520). Under deep UV illumination (<225 nm), the foreign filler in the surface-reaching fractures fluoresced strongly pink while the spodumene host rock was inert. The effect was especially prominent in a cavity near the girdle (figure 4).

Figure 5. Color concentration within surface-reaching fractures confirmed dye treatment in the spodumene. Photomicrograph by Guy Borenstein; field of view 2.66 mm.
Microscopic examination verified the FTIR, UV-Vis-NIR, and deep UV findings and revealed surface-reaching cleavages and fractures filled with a red foreign substance (figure 5), as well as natural inclusions.
The recorded results confirmed the gem as a red-dyed spodumene. Although spectroscopy identified some manganese, the lack of pink/red reaction under deep UV suggests a low concentration (Lu, 2012). Therefore, the authors assume that the starting material was either colorless or very pale pink spodumene.
Introducing red dye to intensify the color of corundum is a longstanding practice (Schmetzer et al., 1992). To the best of our knowledge, however, this is the first time a spodumene has been treated with a colored oil to imitate ruby. The result masks the true identity of the gem, and without gemological testing, an uneducated trader could misidentify it as a color-enhanced ruby. Source: GIA @topic:3


Title: Update from Mozambique’s Ruby Mines Abstract: Figure 1. Mining of the gravels at Mugloto pit 3 in the MRM concession. The gravel layer is around 30 cm thick. The material on top has a distinct reddish tint that is typical for sediments in tropical environments. Under the layer of gravel, the weathered basement rock is more grayish in color. Photo by Wim Vertriest; courtesy of MRM.
Mozambican rubies have revolutionized the dynamics of the ruby trade since their debut on the global gem scene in 2009. GIA has been following the evolution of the deposits around Montepuez in the Cabo Delgado Province of northern Mozambique since the very beginning (see W. Vertriest and S. Saeseaw, “A decade of ruby from Mozambique: A review,” Summer 2019 G&G, pp. 162–183). In August 2022, a GIA field gemology team visited the mining area to document the current state of mining and to collect samples for future studies.
In less than a decade, the balance has shifted from an informal environment dominated by artisanal miners and foreign buyers to a situation that is mostly under the control of large-scale miners who bring these rubies directly to the global market.
There are currently three of these major operations working in the area east of Montepuez.

Montepuez Ruby Mining (MRM): A partnership between Gemfields and local partner Mwiriti that has been mining rubies since 2012. Gemfields also mines Zambian emeralds at the Kagem mine.
Fura Gems: This company has been involved in Mozambican ruby mining since 2019. Some of their concessions were previously worked by Mustang Resources. Fura is also actively mining Colombian emerald and Australian sapphire.
GemRock: Owned by luxury jewelry brand DiaColor, this operation has been active on the ground since 2019.

In terms of geological formation, the ruby mineralization in the Montepuez area is not yet fully understood. The gems are generally described as amphibole-related corundum since the associated rocks are rich in amphibole. This mineral also dominates the inclusion scene of these gems.
While some primary mineralization is known and these ruby-bearing bodies are areas of interest for the mining companies, the rubies are seldom mined from the host rock. Nearly all of the mining activity is focused on the secondary deposits. These weathered gravel layers are rich in rubies and referred to locally as camada. This type of material is easy to mine, and the value of the ruby found here is higher than that in the primary deposits. The original host rock may contain higher volumes, but the majority of this corundum tends to be of very low grade. The exploration strategies of the mining companies focus heavily on identifying the extent, thickness, and distribution of the secondary gravels throughout their respective concessions. Understanding the geological formation of the corundum in this geological setting is a continuing process. Exploration teams are actively delineating and characterizing the ore bodies that hold the primary mineralization.
All three large-scale operations extract these ruby-rich gravels by stripping the overburden with excavators. This exposes the camada, which is dug up and stockpiled near the wash plants (figure 1). Local variations of the gravel layers can provide additional challenges. In some areas the sediment cover is less than 50 cm thick, which means the shallow gravel layer contains an abundance of roots, branches, and other organic material, making it harder to process further down the line. In other areas, the gravels are buried over 15 m deep, requiring serious effort and planning to strip the overburden. The ruby-rich layers themselves can vary from 10 to 150 cm; in some cases, multiple layers are present. The main one is always lying directly on the (extremely weathered) basement rock, which often consists of amphibolites, gneisses, and occasional felsic pegmatite veins.

Figure 2. The first step in the wash plant at Fura is the feeding bin (top left), where material enters the washing process. While the material moves down through the bins, water is added and a first screening removes large boulders. The trommel serves a dual function, breaking up clay lumps and screening out oversized materials. This image captures the first of seven steps to reduce the gravel to a concentrate rich in ruby, which is then handled in the sort house. Photo by Wim Vertriest; courtesy of Fura Gems.
While washing the rubies out of the gravel sounds very straightforward, this is a complex engineering process that requires careful monitoring and control. The gravels are unsorted, with quartz boulders up to 30 cm in diameter, but can also have a significant clay content. Processing them is no easy task and requires many steps of separating by size as well as various techniques to break up sediment clusters and concentrate the ore. Sizing is routine, but the other steps require considerable effort. At all of the large mining operations, logwashers, rotating trommels, and high-pressure water jets are used to break up clay clumps (figure 2). Concentration of the gravels (i.e., removal of the unwanted minerals) focuses on separating based on the specific gravities of the components of the sediment. Ruby is relatively dense compared to most other minerals such as feldspar and quartz. The most convenient method is using a pulsating jig where the waterlogged gravels move across a screen with barriers while getting pushed up vertically. This allows lighter materials to wash over the jig while denser minerals are concentrated at the bottom. While simple, this technique has its limitations, and several of the mines have progressed to more advanced techniques that allow for more precise separation and/or higher capacity, such as dense media separators and rotating pans in which a slurry with a precisely controlled density is used to separate heavier mineral fractions.
All of these techniques require large volumes of water. Plant operators assume that every metric ton of gravel processed requires 1000 liters of clear water. This water consumption was a decisive factor for development of the wash plant. For instance, a nearby river can serve as a cheap and constant supply of water, while boreholes are a much more costly alternative. As such, considerable effort is put into recycling water using settling ponds, cyclones, and flocculants. This allows much of the water, sometimes up to 90%, to be reused in the cleaning process.
With three large-scale mines operating in the area, the volumes of gravel processed are immense. The combined washing capacity of the three mines is more than 500 metric tons per hour.

Figure 3. At GemRock, the concentrate from the wash plant is fed onto a conveyor belt where teams of sorters handpick the rubies. The workers are using gloveboxes to prevent physical access to the stones. At the end of the shift, the rubies are collected and inspected. Photo by Wim Vertriest; courtesy of GemRock.
The final product coming out of the wash plant is an intensely concentrated mix of heavy minerals enriched in ruby, though considerable portions of garnet, iron oxides, and other minerals are still present. Initially simple techniques such as manual sorting were used to handpick the rubies from this mix. As these operations grew, however, more advanced technology has been applied. Optical sorting devices are able to recognize rubies by their fluorescence and separate them from the mix. Most mines use these devices nowadays, often with manual control of the rejects since the machines are not flawless. In a final step, the mix of rubies is graded based on clarity, color, and size. Some mines perform this detailed and specialized task at company headquarters, while others do so at the mine. During the final stages of concentrating the rubies, security procedures become increasingly strict. Automatic sorting and gloveboxes (figure 3) are used to avoid contact with the rubies. The final grading, which must be done manually by experienced specialists, is heavily supervised in secured spaces. This is one reason why some companies prefer to do this at their headquarters.
The further development and growing importance of these large-scale mining operations has also brought changes to the artisanal mining communities. These garimpeiros mined 100% of Mozambique’s rubies in the first years after the discovery in 2009. Only in 2014 did the first rubies from large-scale mining reach the international market, through an auction hosted by MRM. Not all of these small-scale miners are local; many traveled from other provinces in Mozambique or even from neighboring countries such as Tanzania. In recent years, the importance of the garimpeiro in Mozambique’s ruby market has been in decline. Legal codes were adjusted to make unlicensed mining a crime, allowing government officials to intervene with the artisanal mining activities that took place on the licenses of the large companies. As compensation, the government created areas designadas that were assigned to the artisanal miners. However, these are often small and nearly barren. At the moment, these areas cover an area of four square kilometers. The mining licenses secured by the large-scale mining companies cover over 2,000 square kilometers. Conflicts over mining rights have created considerable tension between established powers and the local communities. Some of these disputes are only now coming to light or are just beginning to be felt.
But the most drastic impact on the artisanal mining community has probably been the sanctions against the foreign buyers in the neighboring towns. Ruby buyers, mainly from Asia, have worked from offices near Montepuez to buy directly from the garimpeiros since 2008–2009, but their numbers have been drastically reduced in recent years. This has almost completely eliminated the main clientele for the artisanal ruby miners. During GIA’s visit in 2016, huge numbers of garimpeiros (tens of thousands of them) could be seen working and traveling throughout all the mining concessions east of Montepuez. During GIA’s recent 10-day expedition in August 2022, only 37 artisanal miners were seen in the same area. Most of the artisanal activity has moved farther east toward the city of Chiure, where the garimpeiros are mining more recent river sediments that are rich in rubies. Many have returned to their home villages, while some of the locals have found employment with the large mining companies.
The Cabo Delgado Province is currently experiencing social and political turmoil. Religious extremist groups under the name Ahlu-Sunna wa al Jama’a have been growing more violent. This has forced many people to abandon their villages and relocate to the southern reaches of the provinces, where the mines are located. One company reported that the number of people residing on their mining license increased from 1,500 to more than 20,000 in less than one year.
The local political structure also lacks the strength to successfully empower the local communities. All large-scale miners pay significant royalties and taxes to Mozambique’s central government. Unfortunately, many of these funds fail to reach the historically underprivileged communities surrounding the mines in the northern Cabo Delgado Province. This only amplifies social unrest. Many local projects have been set up by the large companies as part of their own corporate social responsibility programs, focusing on a sustainable food supply, transportation, and healthcare.
The last five years have brought dramatic change to ruby mining around Montepuez. Nowadays the dominant players are the larger operations and no longer the garimpeiro community with their associated trading network. These large-scale miners have immensely upgraded and professionalized their operations since their initial exploration and early mining phases. They have integrated more sophisticated techniques in both the gravel processing and the sorting. Larger fleets of machinery and fine-tuned wash plants allow huge volumes of ruby ore to be handled. This has resulted in a more stable ruby supply to the international markets.
However, the situation on the ground remains unstable, with social unrest growing in the wider areas where the ruby mining is happening. Only time will tell how this situation will evolve. Source: GIA @topic:1


Title: Interesting Metallic Platelets in a Brazilian Paraíba Tourmaline Abstract: Figure 1. A 2.52 ct oval modified brilliant Paraíba tourmaline. Photo by Adriana Gudino.
The authors recently examined the 2.52 ct saturated green oval modified brilliant shown in figure 1. The gemological properties, as well as trace element analysis using laser ablation–inductively coupled plasma–mass spectrometry, confirmed this gem was a Paraíba tourmaline from Brazil.

Figure 2. Left: The skeletal formation that usually indicates very rapid growth of the mineral. Right: Skeletal formations showing a cross-hatch pattern. Photomicrographs by Shiva Sohrabi; fields of view 1.26 mm (left) and 2.95 mm (right).
Microscopic observation revealed interesting metallic dark gray dendritic inclusions (figure 2). The metallic inclusions were similar in shape to previously documented native copper inclusions in Paraíba tourmaline (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Volume 1, 2008, Opinio-Verlag Publishers, Basel, Switzerland, p. 167). Metallic inclusions with a dendritic pattern and similar brassy color in a Brazilian Paraíba tourmaline were previously identified as native copper (F. Brandstätter and G. Niedermayr, “Copper and tenorite inclusions in cuprian-elbaite tourmaline from Paraíba, Brazil,” Fall 1994 G&G, p. 181). Because the inclusions in figure 2 are different in color from those previously documented, they are probably not copper. However, Raman analysis was unsuccessful in identifying them. Based on their morphology and color, the authors speculate they could be ilmenite, which has been observed as skeletal inclusions of a similar color in gems such as emerald. These are the first examples of dark gray skeletal metallic inclusions the authors have encountered in a Paraíba tourmaline. Source: GIA @topic:11


Title: Unusual Fibrous Inclusions in Blue Opal Abstract: These unusual clusters of curled fibers were seen in a blue opal. Photomicrograph by Nathan Renfro; field of view 3.58 mm

The authors recently encountered an opal with a grayish blue bodycolor and weak play-of-color. The gem also contained some interesting fibrous inclusions (see above). The inclusions were generally scattered throughout a planar zone as curled bundles of chatoyant fibers. This type of opal appeared to be naturally colored and consistent in appearance and physical properties with opal from Sinaloa, Mexico (Fall 2011 Gem News International, p. 243). Raman analysis was unable to identify the inclusions, but a strong cristobalite signal was measured in areas with the fibers and without them, suggesting a volcanic origin (E. Fritsch et al., “Green-luminescing hyalite opal from Zacatecas, Mexico,” Journal of Gemmology, Vol. 34, No. 6, 2015, pp. 490–508). While the exact nature of these inclusions remains a mystery, this is the first time the authors have encountered this type of unusual coiled fibrous inclusion in blue opal. Source: GIA @topic:11


Title: Quarterly Crystal: Rutile on Hematite Abstract: Figure 1. Measuring 39.83 mm and weighing 178.33 ct, this Pakistani hematite crystal is host to a geometric outer skin of sagenitic rutile. Photo by Diego Sanchez.

When we think of the micro-world of gems and minerals, we usually think of transparent to translucent host materials. However, there are also a number of opaque minerals used as gems that are composed of chemical elements such as copper, iron, and titanium. One of these is hematite.
Recently we had the opportunity to study an unusual hematite crystal sent by Ali Shad of Shad Fine Minerals in Gilgit-Baltistan, Pakistan. The geographic source for the hematite crystal pictured in figure 1 is the Yangslo mine, located in the Basha Valley of Gilgit-Baltistan. At 178.33 ct and 39.83 mm in the longest direction, this “floater” hematite crystal (with no points of attachment to the surrounding rock) plays host to a sagenitic network of epitaxial, surface-oriented, opaque dark gray acicular rutile crystals as large as 4 mm in length.

Figure 2. The sagenitic epitaxial structure of the acicular rutile crystals on the surface of this hematite gives the substrate an otherworldly appearance. Photomicrograph by Nathan Renfro; field of view 11.28 mm.
Using laser Raman microspectrometry, the identification of the sagenitic crystals was confirmed as rutile. Energy-dispersive X-ray fluorescence (EDXRF) analysis showed the dominant presence of iron and titanium, with a trace of manganese. As shown in figure 2, the euhedral rutile crystals were situated on the hematite crystal in the form of a geometric sagenitic boxwork. Source: GIA @topic:2


Title: Quarterly Crystal: Pyrite in Quartz Abstract: Figure 1. This example of Colombian pyrite-containing rock crystal weighs 466.27 ct and measures 61.90 mm in length. Photo by Diego Sanchez.

Pyrite and quartz are two relatively common minerals. Transparent colorless quartz, known as rock crystal, is host to a wide variety of mineral and fluid inclusions, more so than any other gem mineral. While pyrite and rock crystal are both common, finding a good example of crystalline pyrite inside of rock crystal quartz is a gem mineral collector’s prize.

Figure 2. These modified octahedrons of pyrite were deposited along one prism face of their quartz host. Photomicrograph by Nathan Renfro; field of view 7.62 mm.
Known for its fine emeralds, the Chivor mine in Colombia is also a mineralogical source of both pyrite and colorless quartz. On occasion, crystals of Colombian quartz are known to host pyrite. As shown in figure 1, we recently had the opportunity to examine one such specimen, which hosted numerous bright metallic brassy yellow modified octahedrons of pyrite (figure 2). The inclusions were not randomly scattered throughout the 466.27 ct quartz, but instead were situated neatly just under the surface of one of the prism faces. Another interesting feature was that all of the pyrite inclusions were present in a range of sizes with well-defined crystal faces, suggesting that the pyrite crystals precipitated syngenetically (at the same time) from a directional fluid rich in pyrite forming iron sulfide. Source: GIA @topic:2


Title: Conichalcite in Quartz Chalcedony Abstract: Raman spectrometry identified the yellowish green inclusions in this chalcedony host as the copper mineral conichalcite. Photomicrograph by Nathan Renfro; field of view 7.20 mm.

An interesting greenish blue cabochon of chalcedony was examined to determine the identity of some peculiar yellowish green inclusions. The bodycolor offered some clues, as the greenish blue variety of chalcedony, known as “gem silica,” is commonly attributed to the copper mineral chrysocolla. Therefore, it was not a surprise when Raman spectrometry identified the yellowish green inclusions as another mineral that contained a significant amount of copper: conichalcite (see above).
Conichalcite, CaCu(AsO4)(OH), is a member of the adelite-descloizite group and occurs in colors from dominantly green to dominantly yellow, with either a yellow or green modifier. Conichalcite is reported to occur with chrysocolla from deposits in the United States (Utah, Arizona, and California), Germany, Peru, and Australia. This particular gem was reportedly from Concepcion Del Oro, Zacatecas, Mexico.
These vibrant inclusions were quite visually striking when seen along with their greenish blue host chalcedony. This is the first time the authors have identified inclusions of conichalcite in chalcedony. Source: GIA @topic:2


Title: “Dragon’s Eye” Fire Agate Abstract: Upon close examination, the polished botryoidal knob in this Mexican fire agate resembles a reptilian eye. Photomicrograph by John Koivula; field of view 8.12 mm.

	Found in only a few places in the southwestern United States and Mexico, fire agate is a very finely layered golden brown to reddish brown agate with a botryoidal multi-layered structure. Each of the individual layers in a fire agate is dusted with the iron hydroxide mineral goethite, which provides the brown bodycolor.

	What makes fire agate particularly special is that the ultra-thin coatings of goethite cause a very colorful iridescence, primarily in red, golden orange, and green, but occasionally in violet to blue. The vibrant colors result from interference between light rays that are reflected and refracted while traveling through the gem and reflecting from these ultra-thin layers.

	The finest-quality fire agates can rival Australian black opal. Because they are a form of chalcedony quartz, fire agates are also more durable than opal, making them suitable for virtually any jewelry application.

	The 4.62 ct (10.22 × 9.16 × 7.19 mm) Mexican fire agate studied here, a polished high-dome cabochon, is from the El Terrero mine in the Calvillo Mountains of Aguascalientes State, Mexico. Under close examination, its somewhat ovoid botryoidal structure and fine granular texture, together with the banded red, orange, and green coloration, project the image of a reptilian “dragon’s eye.” As an added bonus, the hotspot created by the fiber-optic light at the apex of the gem adds an elegant finishing touch to the overall image. Source: GIA @topic:2


Title: An Extraordinarily Large Cat’s-Eye Emerald Abstract: Figure 1. An unusually large cat’s-eye emerald weighing approximately 126 ct. Photo by Shunsuke Nagai.
Emerald in cabochon form sometimes displays a chatoyant effect, and comparatively large cat’s-eye emeralds are highly sought after. GIA’s Tokyo laboratory recently examined an extraordinarily large semitransparent green cabochon measuring 31.3 × 26.2 × 20.9 mm and weighing approximately 126 ct (figure 1). The stone had a spot refractive index of 1.58 and showed specific chromium absorption lines in the red through a handheld spectroscope, and standard gemological properties identified it as emerald.

Figure 2. Inclusions observed in the large cat’s-eye emerald. A: Rain-like inclusions; field of view 2.18 mm. B: Unknown whitish granular flake-like inclusions; field of view 5.70 mm. C: Aggregates of tiny whitish feldspar crystals confirmed by Raman spectroscopy; field of view 3.60 mm. Photomicrographs by Makoto Miura.
The emerald contained numerous reflective rain-like inclusions creating a chatoyant effect (figure 2A), whitish granular flake-like inclusions (figure 2B), and aggregates of tiny whitish crystals which were identified as feldspar by Raman spectroscopic analysis (figure 2C). The ultraviolet/visible/near-infrared absorption spectra showed two broad bands of Cr3+ at 430 and 600 nm, with a large Fe2+ band at around 850 nm and an Fe3+ broad band at 372 nm. Trace element chemical results using laser ablation–inductively coupled plasma–mass spectrometry showed that this emerald had a high iron concentration (2800–2930 ppmw) and medium potassium range (67.8–74.3 ppmw), characteristics similar to the published data of emeralds from the Belmont mine in Minas Gerais, Brazil (e.g., S. Saeseaw et al., “Geographic origin determination of emerald,” Winter 2019 G&G, pp. 614–646). Inclusions observed in this emerald were also consistent with a Brazilian origin (again, see figure 2).
Brazil is a well-known source of large emerald crystals. One previous report (Summer 2015 Gem News International, pp. 200–201) described a 43 ct Brazilian cat’s-eye emerald. The cat’s-eye emerald examined here is notable for its size and transparency, and it is one of the largest examined by a GIA laboratory to date. Source: GIA @topic:3


Title: Apatite Oiling: Before and After Abstract: Figure 1. Left: On the base of this apatite cabochon (15 × 15 × 13 mm), a large, reflective fissure can be observed with fiber-optic illumination. Right: After the oil filling, the same fissure is much less noticeable and the iridescent reflective area is considerably smaller, enhancing the sample’s clarity. Photos by E. Billie Hughes.
Fissure filling of gemstones is an age-old treatment that can improve a stone’s clarity (Fall 2020 Gem News International, pp. 443–444). By introducing oil or other fillers such as resin into the stone, the treater can minimize the appearance of fissures.
Recently we had the opportunity to observe this treatment up close in an apatite cabochon brought to our laboratory for photography while it was still untreated. Then the sample was oiled by Jeffery Bergman and returned to the laboratory for observation and photography.
Upon examination before and after, the effects of the treatment were clear. On the base of the cabochon, a large, reflective fissure became less visible after oiling (figure 1). Using fiber-optic illumination, it was apparent that the filler had diminished the reflective appearance of the fissure, with only small highly reflective areas remaining (figure 2). Darkfield illumination also revealed a stark difference in appearance: The filler had rendered large dark areas filled with air nearly invisible (figure 3).

Figure 2. A close-up of the fissure before and after oil treatment, shown in diffuse fiber-optic illumination. Left: Before oiling, the fissure is easily visible and highly reflective. Right: After oiling, the reflection is more muted and less noticeable, with only a small highly reflective area remaining. Photomicrographs by E. Billie Hughes; field of view 10 mm.

Figure 3. Left: Before filling, transmitted light shows dark areas where air has become trapped in the fissure, making it more visible. Right: Treatment with oil minimizes the dark areas, enhancing clarity. Photomicrographs by E. Billie Hughes; field of view 27 mm.
This microscopic observation serves as a reminder of the significant impact clarity enhancement can have on gems of all types. Source: GIA @topic:3


Title: “Sun Spangle” in Amber Abstract: A “sun spangle” created in amber as a result of rapid cooling. Photomicrograph by Aamir Sayed; field of view 1.5 mm.
Fractures often diminish a gemstone’s beauty and appeal. To reduce the detrimental effects caused by fractures and to enhance appearance, many gemstones undergo treatment. But not all fractures are undesirable. One such example is the circular stress fracture in amber (see above) recently encountered by the author.
Minute gas bubbles in amber cause cloudiness, which can be removed by heating the material. If the amber cools too rapidly, it may develop internal circular stress cracks called “sun spangles.” Sun spangles are considered desirable and are often created deliberately, such as the attractive example shown here. The concept can be likened to the Japanese art of kintsukuroi or kintsugi, in which broken pottery is repaired with gold undisguised, embracing the piece as more beautiful for having been broken. Source: GIA @topic:2


Title: GIA Field Gemologists Seek Ruby in Mogok, Myanmar Abstract: Searching for Ruby in Mogok

	Join GIA field gemologists in a search for ruby in Mogok, Myanmar.

	Venture into Myanmar’s Mogok mining area and its bustling gem markets with GIA Field Gemologists Vincent Pardieu and Andy Lucas, who traveled to this legendary location in January and February of 2014 with videographer Didier Gruel.

	This video focuses on ruby, Mogok’s most iconic gem. Mogok has an unparalleled reputation as the source of fine rubies that goes back more than 800 years. Rubies are mined either from the gravels of secondary deposits or deep underground from primary deposits in marble.

	The Mogok mining area is about 400 miles (650 km) north of Yangon in a densely vegetated, mountainous area rising to 7,700 feet (2,347 meters) above sea level.

	At most mines, you’ll find Kanase women searching through the white marble tailings for traces of the area’s fabled rubies, the surroundings ringing with the impact of their hammers. By local tradition, they have the right to keep the gemstones they find. These women can also be seen selling their finds at the open gem markets.

	While there, Pardieu negotiated with them for gemological samples—the rubies and spinels often found in the marble host rock. “The only better solution would be for us to go down into the mine and find the samples ourselves,” says Pardieu, looking at pieces the women offered him, “but you could spend hours and hours hammering the marble to collect that—this is really good.”

	In the video, you’ll also venture into the depths of Mogok’s underground mines, some of which are more than 980 feet (300 meters) deep, requiring long, tricky descents. The difficult access hints at the effort the miners must make day after day to reach ruby-bearing rock. “Now we start to understand the value of rubies,” explains Pardieu. Uncovering ruby requires stamina and faith, he says. “It’s a lot of hard work and it’s a lot of hope from the miners—it’s a mix of hope and hard work.”

	These GIA Field Expeditions (FE49 and FE50) took place in February 2014. Source: GIA @topic:7


Title: Pseudo-Icosahedral Pyrite in Colombian Emerald Abstract: A pseudo-icosahedral crystal of pyrite in a 2.88 ct Colombian emerald. Photomicrograph by Taku Okada; field of view 1.01 mm.
The author recently examined a 2.88 ct emerald containing a beautiful metallic yellow pseudo-icosahedral pyrite crystal with truncated edges (see above). The emerald was identified as Colombian based on its jagged three-phase inclusions and trace element analysis using X-ray fluorescence. The included crystal’s color, luster, and shape were characteristic of pyrite, which is sometimes found in emeralds from various countries (S. Saeseaw et al., “Geographic origin determination of emerald,” Winter 2019 G&G, pp. 614–646). Pyrite, also known as “fool’s gold,” belongs to the isometric crystal system and has an ideal chemical composition of FeS2.
Like other isometric or cubic minerals, including diamonds and garnets, pyrites exhibit various morphologies depending on growth parameters such as temperature and/or degree of supersaturation (J.B. Murowchick and H.L. Barnes, “Effects of temperature and supersaturation on pyrite morphology,” American Mineralogist, Vol. 72, 1987, pp. 1241–1250). A regular icosahedron is one of the five classic Platonic solids, but it cannot exist in a crystal because it contradicts Haüy’s law of rational indices, which states that the intercepts of any crystal face along the crystallographic axes are either equal to the lattice constant lengths or some simple whole number multiples of them. Goniometric studies by Romé de L’Isle from 1783 showed that a pseudo-icosahedral form, often found in pyrite, is a combination of a regular octahedron and an irregular pentagonal dodecahedron known as a pyritohedron.
This pyrite crystal in Colombian emerald would be a welcome sight for any gemologist. Source: GIA @topic:2


Title: Kunzite Description Abstract: Kunzite’s beauty is apparent in both its natural crystal and faceted forms. - Robert Weldon

                      Kunzite is the light pink to violetish purple variety of the mineral spodumene. It’s found in Afghanistan, Brazil, Madagascar, and the US state of California. The gem was named after pioneering gemologist George Frederick Kunz (1856-1932).

	This group of kunzite crystals was recovered from the Oceanview Mine in the Pala mining district of San Diego County, California. - Brendan Laurs
Kunzite has two perfect cleavage directions. It’s pleochroic, with the best color visible when you look down the length of the crystal. Cutters keep these factors in mind when they orient gems for finishing. They might also cut a kunzite deep to emphasize its pink to violet color.

	This lovely faceted kunzite displays an example of the best color this gem has to offer. - Robert Weldon
It is not unusual to find kunzite in large sizes. The Smithsonian Institution houses a faceted heart-shaped kunzite that weighs 880 carats.

Kunzite can be irradiated and then heat-treated to enhance its color. Both treated and natural color in kunzite can fade with exposure to heat and bright light. Source: GIA @topic:1


Title: Rare Kashmir Star Sapphire Abstract: Figure 1. An approximately 15 ct blue Kashmir star sapphire set in a combination ring and pendant with near-colorless pear and marquise brilliants. Photo by Annie Haynes.
A rare star sapphire of Kashmir origin, mounted in a combination ring and pendant (figure 1), was recently examined in the New York laboratory. Kashmir has long been regarded as the most sought-after source of blue sapphire since the deposit’s discovery in the late nineteenth century. Words such as “sleepy” or “velvety” are often used to describe their characteristic appearance, which can be attributed to the scattering of light as it interacts with “milky” bands of microscopic particles within the stone. Due to the locality’s limited production, Kashmir sapphires are scarce in the market, and star sapphires are particularly uncommon (R.W. Hughes et al., Ruby & Sapphire: A Gemologist’s Guide, 2017, RWH Publishing/Lotus Publishing, Bangkok, p. 477).

Figure 2. Wispy stringers among sharp milky bands of microscopic particles. Photomicrograph by Emily Jones; field of view 3.57 mm.
This blue cabochon star sapphire was estimated to weigh around 15 ct. A spot reading gave an approximate refractive index of 1.76, matching corundum. Microscopic inspection revealed sharp, angular milky bands and particle streamers (figure 2), both features that are typical of Kashmir sapphires. Several sparse short silk needles were also observed (figure 3). Asterism in corundum is generally caused by the reflection of light off of exsolution rutile silk needles. This sapphire’s star, however, was generated by light reflected from the crystallographically oriented bands of minute particles.

Figure 3. Several short needles of exsolution silk amid the abundant particle stringers. Photomicrograph by Emily Jones; field of view 1.85 mm.
Further testing of the sapphire’s spectral and chemical properties was carried out to help determine its geographic origin. Laser ablation–inductively coupled plasma–mass spectrometry revealed a trace element chemistry consistent with stones of known Kashmir origin, based on GIA’s internal reference data. This, coupled with the material’s internal characteristics, confirmed that the star sapphire was in fact from Kashmir. No evidence of heat treatment was detected. While the majority of corundum on the market is heated to improve color, high-quality sapphires from Kashmir are generally left untreated.
Kashmir sapphires are rare enough in their own right. Furthermore, a large star sapphire from this historic locality is truly an extraordinary sight, and certainly a first for the author. Source: GIA @topic:3


Title: Unique Star Sapphire with Transparent Core Abstract: Figure 1. This 34 ct sapphire cabochon has a yellow pseudohexagonal window surrounded by metallic-looking material that displays asterism. Photo by Shunsuke Nagai.

GIA’s Tokyo laboratory recently examined a 34 ct oval cabochon of unique appearance. This cabochon consisted of a transparent yellow pseudohexagonal core in an opaque metallic-looking area (figure 1). Spot refractive indices (RIs) on both areas were 1.76, and specific gravity (SG) was 4.04. This appearance of a transparent yellow window with an opaque metallic surrounding area is reminiscent of pallasitic peridot, an olivine nodule enclosed in nickel-ion alloy of stony-iron meteorites (see J. Sinkankas et al., “Peridot as an interplanetary gemstone,” Spring 1992 G&G, pp. 43–51). However, no surface discontinuity between these two parts can be found with close observation under reflected light. Furthermore, this metallic-looking area exhibited six-rayed asterism. Under the microscope, negative crystals in a plane and healed fissures were found in the transparent area; densely packed needle-like inclusions, some crystals, and stained fissures were seen in the opaque area (figure 2). In addition to the microscopic observations, advanced testing of the yellow part revealed that this specimen was a natural corundum. The metallic appearance and asterism were caused by the strong reflection from the dense needle-like inclusions (figure 2), some of which were flat. These needles were identified as hematite and ilmenite by Raman spectroscopy. The slightly elevated SG of this specimen might have been caused by the abundance of these inclusions, since the SGs of both hematite and ilmenite are higher than that of corundum.

Figure 2. The sapphire’s yellow core includes negative crystals and healed fissures (left) and the metallic-looking part (right) has dense needles. Photomicrography by Makoto Miura; field of view 3.38 mm.
As previously documented (e.g. T.N. Bui et al., “From exsolution to ‘gold sheen’: A new variety of corundum,” Journal of Gemmology, Vol. 34, No. 8, 2015, pp. 678–691; N. Narudeesombat et al., “Golden sheen and non-sheen sapphires from Kenya,” Gem and Jewelry Institute of Thailand, July-August 2016, pp. 282–288; Winter 2016 Lab Notes, pp. 413–414), sapphires with golden shimmer caused by hematite needles are known as “golden sheen” or “Zawadi” sapphires in the trade. As with rutile needles in common star sapphires, hematite needles intersecting at 60 degrees can cause six-rayed asterism. Golden sheen sapphires sometimes have densely included parts, but such a distinct zoning of transparent and densely included parts has not been documented. This unique appearance may indicate a certain crystallizing condition of sapphires. Source: GIA @topic:3


Title: Dendritic Inclusions of Thorianite in Heated Blue Sapphire Abstract: Figure 1. Thermal enhancement and unusual inclusions were detected in this 2.05 ct blue sapphire, measuring 7.07 × 6.55 × 4.99 mm. Photo by Kaiyin Deng.

Recently, a 2.05 ct blue sapphire was sent to Guild Gem Laboratories for identification (figure 1). Standard gemological testing confirmed it was corundum, with a refractive index of 1.762–1.770 and specific gravity of 4.00. Under microscopic observation, cloudy particles and diffuse straight color zoning were seen, as well as fingerprint-like fluid inclusions as shown in figure 2, indicating that this stone had undergone thermal enhancement. This sapphire exhibited chalky greenish fluorescence around the girdle under short-wave (254 nm) ultraviolet fluorescence light. Further UV-Vis spectroscopic testing suggested a metamorphic origin, while FTIR spectra (figure 3) showed a distinct 3309 series at 3185, 3232, 3309, and 3367 cm–1, confirming heat treatment. Energy-dispersive X-ray fluorescence (EDXRF) showed an Fe content around 300–500 ppm. Neither U nor Th was detected.

Figure 2. Left: Dendritic inclusions consisted of dot-like minerals showing a “melted and diffused” appearance. Photo by Yujie Gao; field of view 2.68 mm. Center: Resembling a tree root, these dendritic inclusions showed relatively strong metallic luster under reflected light. Photo by Yizhi Zhao; field of view 2.52 mm. Right: Dendritic inclusions coupled with blurred blue color zoning. Photo by Yujie Gao; field of view 9.73 mm.

Figure 3. The sapphire’s FTIR spectrum exhibited a distinct 3309 series at 3185, 3232, 3309, and 3367 cm–1.

Figure 4. Raman spectra of the sapphire’s dendritic inclusions matched with thorianite (ThO2).
Also observed were interesting dendritic inclusions, which are not very common in sapphire. These inclusions showed relatively strong metallic luster under reflected light, and they appeared to be opaque under transmitted light. Lines of small dots were seen under higher magnification. These dot-like inclusions exhibited a blurred surface and a rounded shape. Raman analysis at the National Gemstone Testing Center (NGTC) using a 473 nm laser showed three distinct peaks at 466, 552, and 607 cm–1, matched very well with thorianite, according to the RRUFF online database (rruff.info), as shown in figure 4. Thorianite (ThO2) is an oxide mineral mainly composed of Th and O, first found in an alluvial deposit in Sri Lanka (D. Wyndham, “The occurrence of thorium in Ceylon,” Nature, Vol. 69, 1904, pp. 510–511). A melted appearance of a mineral inclusion and/or unnatural-looking discoid fractures around inclusions can be indicative of heat treatment in corundum. Such phenomena are normally attributed to the breakdown of mineral inclusions at high temperature. However, the thorianite inclusions here did not have the typical appearance of inclusions that have been altered by high-temperature heat treatment. The diffuse appearance of thorianite is unlikely to be an indicator of heat treatment. Further experiments and tests on thorianite in unheated sapphire would give us more clues in the future. Source: GIA @topic:3


Title: Series of Articles on Rubies from Mozambique Abstract: View Gallery

Rubies from Montepuez, in northern Mozambique, have dominated the Thai market, the world’s major ruby trading center, since the discovery of this deposit in the spring of 2009. GIA has engaged in an extensive study of this material, culminating in October 2013 with the Bangkok laboratory’s most recent paper, “Rubies from the Montepuez Area.”

These specimens are quite different from those traditionally encountered in the market, such as the marble-type rubies from Mogok and Mong Hsu, whose strong fluorescent aspect is related to low iron content, or basalt-related rubies from Thailand and Cambodia, known for their low fluorescence due to higher iron content. Indeed, the new deposit in Montepuez is an amphibole-related deposit similar to those near Winza (Tanzania), M’Sawize (Mozambique), and probably the deposit near Didy (Madagascar), three other ruby deposits discovered fairly recently in Africa.

Amphibole-type rubies generally have higher iron content than those found in marble-related deposits  and lower iron content than those from basalt-related deposits. These nontraditional amphibole-type metamorphic stones fill the gap, in terms of chemical composition and appearance, between the highly fluorescent marble-type rubies and the weakly fluorescent basalt-related rubies familiar within the trade.

For gemologists, the fact that the rubies from Montepuez come from an amphibole-related deposit is fascinating. That’s because the combination of the inclusion scene, the chemical fingerprint, and the spectra associated with these stones usually distinguishes them  from rubies mined from marble- or basalt-related deposits.

Below are links to publications by GIA gemologists (in chronological order, starting with the most recent) about ruby mining in Mozambique, providing the most complete, up-to-date information on the subject.

GEMFIELDS INAUGURAL ROUGH RUBY AUCTION IN SINGAPORE
By A. Lucas, V. Pardieu
Released July 17, 2014
In June 2014, Gemfields held its first auction of rough ruby from Mozambique. GIA field gemologists went behind the scenes of this groundbreaking event for an insider’s look at the rough gemstone auction world.
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RUBIES FROM THE MONTEPUEZ AREA
By V. Pardieu, S. Sangsawong, J. Muyal, B. Chauviré, L. Massi, and N. Sturman
Released Oct. 15, 2013
In October 2013, GIA’s Bangkok lab produced a study of the samples collected during the September 2012 expedition. The study featured FTIR and UV-Vis spectra and chemical analysis of one reference sample from each of the four main ruby mining sites in the area. The study also included numerous inclusion photos that will enable the gemologist to more easily identify rubies from Montepuez.
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UPDATE ON RUBY MINING AND TRADING IN NORTHERN MOZAMBIQUE
By V. Pardieu and B. Chauviré
Published in Winter 2012 Gems & Gemology, Gem News International, pp. 309–311
In 2011, Gemfields acquired the ruby-producing area near Montepuez and began a major mining project. In the summer of 2012, a team of GIA gemologists visited the area to collect samples from the different mining sites for the GIA reference collection.
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FAPFH/GFF TREATED RUBY FROM MOZAMBIQUE: A PRELIMINARY REPORT
By V. Pardieu, N. Sturman, S. Saesaew, G. Du Toit and K. Thirangoon
Released May 11, 2010
During the spring of 2010, GIA gemologists began collaborating with a Thai gemstone burner who was working on the heat treatment of Mozambique rubies using borax additives. A very similar treatment had been used for about 20 years on Mong Hsu rubies.
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UPDATE ON RUBIES FROM MOZAMBIQUE
By V. Pardieu, P. Lomthong, J.B. Senoble, L.P. Bryl, and S. Jacquat
Published in Winter 2009 Gems & Gemology, Gem News International, pp. 302–303
A discussion of the November 2009 field expedition to M’sawize, Mozambique, within the Niassa National Reserve, to obtain ruby samples for the GIA research collection.
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EXPEDITION REPORT TO RUBY MINING SITES IN NORTHERN MOZAMBIQUE
By V. Pardieu, S. Jacquat, J.B. Senoble, L.P. Bryl, R.W. Hughes, and M. Smith
Updated Dec. 23, 2009
In 2009, GIA’s Bangkok lab led three field expeditions to the ruby deposits of Mozambique. During the second expedition, in November 2009, Vincent Pardieu was able to visit the deposit near M’Sawize village in the Niassa province. Finally, in December 2009, we were able to briefly visit the deposit near Montepuez and collect samples for the GIA reference collection.
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PRELIMINARY OBSERVATIONS ON NEW RUBIES FROM MOZAMBIQUE
By S. McClure and J. Koivula
Published in Fall 2009 Gems & Gemology, Gem News International, pp. 224–225
Results of gemological testing and EDXRF spectroscopy on 24 ruby specimens, received in two separate submissions, reportedly from several different deposits in Mozambique.
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RUBIES FROM THE NIASSA AND CABO DELGADO REGIONS OF NORTHERN MOZAMBIQUE
By V. Pardieu, J. Thanachakaphad, S. Jacquat, J.B. Senoble, and L.P. Bryl
Updated April 16, 2009
In early 2009, GIA's Bangkok lab released a preliminary study on Niassa province rubies, based on samples (reportedly from Niassa) collected in Chanthaburi, Thailand. In May 2009, less than a year after the arrival of rubies from Niassa on the market, a second important deposit was discovered near the city of Montepuez, in the neighboring province of Cabo Delgado. Mining activity rapidly increased, and rubies from Mozambique (unheated, heated or filled with lead glass) became very common in trading centers such as Thailand, as well as the U.S. and the rest of the world.
Learn More Source: GIA @topic:1


Title: Book Review: Ruby & Sapphire: A Gemologist’s Guide Abstract: By Richard W. Hughes, with Wimon Manorotkul and E. Billie Hughes, hardcover, 816 pp., illus., publ. by RWH Publishing/Lotus Publishing, Bangkok, 2017, US$200.00.

Ruby & Sapphire: A Gemologist’s Guide is the updated version of the 1997 classic of this same name. This revised edition by Richard W. Hughes with coauthors Wimon Monorotkul and E. Billie Hughes offers exciting new features, including work by new contributors, updates within the text, and comprehensive analytical data. All the chapters have a beautiful new layout and are artistically designed with colored charts and diagrams, spectacular new photography, and extensive documentation. From the very first pages, Ruby & Sapphire transports the reader on a fantastic journey.

The book starts with a fascinating chapter reviewing the legends surrounding corundum throughout history. The reader will travel in this chapter from ancient civilizations through the Middle East and Europe of the Middle Ages and other eras. This chapter also introduces several antique jewels referenced in the “Ruby & Sapphire in the Ancient World” section written by Lisbet Thoresen.

The following chapters explore the sciences, beginning with the chemistry and crystallography of corundum in chapter 2. The trace-element chemistry of ruby and sapphire from different localities are detailed in a chart by contributor Kenneth Scarratt. Crystal forms, angles, twinning, shapes, and other habits are documented and described. Chapter 3 elaborates on the physics of corundum, including parting, fracture, hardness, and thermal properties. Electrical and optical properties of corundum are review together with phenomena such as color change, asterism, and chatoyancy of ruby and sapphire as well as trapiche stones.

Along with contributors John Emmett, Emily Dubinsky, and Kenneth Scarratt, Hughes defines the role of color in perception in chapter 4. “A Guide to Understanding Color” reviews the chromophores of natural corundum and their colors, using density color diagrams and absorption spectra to illustrate the concentration in ppma. It also analyzes the interactions of trace elements in corundum. This chapter also describes corundum’s visible absorption with the use of handheld spectroscopes. The different sections further explore the topics of absorption and transmission of light in corundum, with data collected by today’s modern spectrophotometers used for advanced gemology testing and research. Quantitative absorption spectra graphs and absorption coefficient formulae enrich this chapter as well.  IR spectra are introduced and detailed in “Seeing Infrared: Deconstructing the Infrared Spectra of Corundum” section by contributor Kenneth Scarratt. Paragraphs on luminescence and pleochroism conclude this chapter.

Hughes considers the next chapter, on the history of inclusion research and microscope illumination techniques as well as inclusion types and their formation “one of the most fascinating and rewarding aspects of gemology.” This chapter may be the most visually striking; it features photomicrographs from authors Richard Hughes and E. Billie Hughes as well as renowned gemologists John Koivula, Nathan Renfro, and Danny Sanchez. Iridescent features in Thai ruby, spectacular crystal inclusions in Mogok sapphire, exsolved rutile needles in Burmese ruby, and other scenes from the fascinating internal world of corundum are explored.

“Treatments” starts with the history of heat treatment in corundum, then moves into types of modern heat treatment (including diffusion treatments). Chapter 6 documents the treatment of several corundum varieties, including geuda sapphire, Mong Hsu ruby, Montana’s Rock Creek sapphire, with photographs before and after treatment. This chapter also describes how to detect treatment, with photomicrographs of altered inclusions, fissure filling, and other examples. Chapter 7 takes the reader into the world of synthetic corundum, including the different crystal growing processes, internal features, and gemological properties. This chapter also offers insight into advanced synthetic corundum growth techniques from Jennifer Stone-Sundberg.

With chapter 8, the book transitions into reviewing assembled materials and coated stones. Chapter 9 focuses on methods of fashioning, with splendid photographs and diagrams detailing cut orientation and shapes. Chapter 10 incorporates explains the qualities by which corundum is judged, including tone and saturation; clarity, cut and weight; phenomenon (when applicable); and quality ranking by locality. It also explores market trends and trade names, and judging phenomenon stones. The auction records of historic rubies and sapphires of note, such as the the 330 ct “Star of Asia,” are also detailed.

Chapter 11 elaborates on the material’s geological features, including rock types, corundum-bearing orogenic belts, and secondary deposits. This geology chapter prepares the reader for the following chapter on world sources. Chapter 12 features stunning photographs of landscapes and mines, rough and faceted specimens, and miners, as well as photomicrographs of ruby and sapphire that display the defining characteristics of different localities. Examples include the Kashmir “snowflake” and exsolved rutile silk in Mozambique ruby. Comprehensive maps and illustrations, timelines of ruby and sapphire discoveries in these countries, and photographs are included.

Since the first edition, a significant amount of information on African ruby and sapphire sources has been added. Gem corundum mines all over the continent are referenced, from southern Africa; southwestern Namibia; central and west African regions like Nigeria, Cameroon, Congo; to eastern countries mines in Uganda, Rwanda, Somalia, Malawi, and Tanzania. The largest sections covering African mines are devoted to Mozambique and Madagascar, which have been the sites of major corundum rushes since the first edition was published. Hughes offers exhaustive description and documentation of these localities. The Asian ruby and sapphire deposits have been also considerably documented and updated, particularly those in Myanmar (Burma), Thailand, Cambodia, and Sri Lanka.

The corundum localities along the Silk Road—Afghanistan, Tajikistan, Pakistan, Nepal, and China, for example—are explored, with their characteristics and properties thoroughly detailed and documented. In the American section, photography of Yogo Gulch sapphires from the William Larson collection, Rock Creek material, and Eldorado Bar Missouri River’s specimens show the beauty of corundum from Montana.

Finally Appendix A on Tagore’s Ruby & Sapphire are sections from the classic Mani-Mala (1879, 1881) by Tagore, featuring illustrations from the book. Appendix B concludes this wonderful book with prices and ID flow charts updated with new localities.

The book also features full-page advertisements from various gem trading companies between each chapter. Without these sponsors, such an amazing book could have not been printed, at least not at this incredibly affordable price point. This advertising also shows the trade industry vision and marketing approach at the time of publication; therefore, these serve as valuable references.

The impressive quantity of references, updates, and amount of information available in the new edition make Ruby & Sapphire an invaluable resource for people in the gem industry. But this book can captivate any reader, thanks to the fascinating crossroads between science, history, art, travel, and other fields. Source: GIA @topic:1


Title: Garnet with Apatite Inclusions Abstract: Figure 1. Left: This 3.07 ct purplish pink “dragon” garnet, as seen in daylight-equivalent lighting, displays eye-visible blue apatite inclusions. Right: Red fluorescence in the garnet due to chromium, as seen using long-wave UV. Photos by Jessa Rizzo; courtesy of Ravenstein Gem Co.

Figure 2. Blue apatite inclusions and rutile needles were prominent throughout the “dragon” garnet reportedly from a new find in Africa. Photomicrograph by Nathan Renfro; field of view 2.40 mm.
The authors recently examined a 3.07 ct garnet sample acquired from Ravenstein Gem Co. by author NR. This gem material, marketed online as “dragon” garnet as an allusion to the mythical creature’s changing eye color, was reportedly from a new find at an undisclosed locality in Africa. It is also notable that Lotus Gemology has reported similar material from Tanzania (Summer 2022 G&G Micro-World, pp. 226–227). The garnet was a delicate purplish pink color under daylight-equivalent lighting (figure 1, left) and showed a fairly strong red fluorescence when exposed to long-wave ultraviolet light (figure 1, right). Also of note, this sample, as well as many of the other examples showcased online, contained vibrant blue inclusions of apatite (figure 2) as well as typical needle-like silk and minute fluid inclusions.

Figure 3. The garnet’s UV-Vis-NIR spectrum suggests the color results mainly from manganese, iron, chromium, and vanadium. Narrow bands at 409, 422, and 430 nm are related to manganese in the garnet structure, while absorption bands related to iron are at ~465 and 488 nm (Z. Sun et al., “Quantitative definition of strength of chromophores in gemstones and the impact on color change in pyralspite garnets,” Color Research and Application, Vol. 47, 2022, pp. 1134–1154). A broad band centered at ~572 nm is from vanadium and chromium absorption.

Figure 4. The photoluminescence spectrum collected from the garnet using a 514 nm laser revealed chromium-related emission consistent with the observed red fluorescence under long-wave UV excitation.
Gemological testing revealed a refractive index measurement of 1.741 and a hydrostatic specific gravity of 3.81. Further gemological testing with laser ablation–inductively coupled plasma–mass spectrometry revealed the major composition to be pyrope (61.5 mol.%), spessartine (29.0 mol.%), grossular (6.5 mol.%), and almandine (2.6 mol.%), a chemistry consistent with pyralspite-series garnets. Notable trace elements in significant quantities were chromium (660 ppmw) and vanadium (343 ppmw) in addition to the rare earth elements yttrium (1206 ppmw), erbium (222 ppmw), and ytterbium (420 ppmw). The ultraviolet/visible/near-infrared (UV-Vis-NIR) spectrum revealed absorption bands that were consistent with the chemical analysis (figure 3), indicating that the color of the garnet results from a mixture of manganese, iron, chromium, and vanadium. Raman analysis confirmed the blue inclusions as apatite. It is also notable that the garnet sample showed a weak color change in daylight compared to various non-standardized, commercially available LED types of lighting, changing from purplish pink to pink-orange. Photoluminescence testing with a 514 nm laser revealed a strong chromium-related emission, consistent with the red fluorescence observed with long-wave UV exposure (figure 4).
The strong red fluorescence, color change under certain LED lights, and presence of significant rare earth elements and vibrant blue apatite inclusions make it quite interesting for any gem collector. Source: GIA @topic:2


Title: “Pond Life” Orbicular Chalcedony Abstract: Figure 1. “Pond Life,” a 50.95 ct orbicular chalcedony cabochon measuring 48.5 × 27.0 × 5.5 mm, evokes a pond. The “frog eggs” are actually iron-containing inclusions surrounded by the host’s concentric growth. Photo by Elise A. Skalwold.

	The seemingly infinite combination of growth features and inclusions seen in microcrystalline quartz fires the imagination, often evoking visual metaphors (see “Aurora Iris Agate” in this column). Such is the case with the orbicular chalcedony seen in figure 1. From a piece of non-descript tumbling rough purchased in 2011, Paul Stalker (Stones by Stalkers, Tioga, Pennsylvania) delighted in creating what he christened “Pond Life,” as the 50.95 ct piece’s polished appearance resembles frog eggs within a pond.

	Exploring the interior of such microcrystalline varieties of jaspers and agates can be just as fascinating as exploring inclusions within single-crystal quartzes, though these opportunities may be overlooked when dazzled by complex macro features. Orbicular chalcedonies such as this ocean jasper are particularly interesting. Here, iron-containing inclusions such as limonite, goethite, and hematite are surrounded by the concentric growth of the host material, which displays the unique fibrous texture found in some types of chalcedony (figure 2, left). Bundles of fibers composed of crystallites are combined with mutually complex optical orientations, giving rise to the eye-visible effect. While beautiful in transmitted, reflected, and polarized light, the addition of various contrast filters can dramatically enhance the details of these subtle growth features, making them easier to study, as well as creating stunning images of a specimen’s inner world (figure 2, right). For more on advanced filtering techniques, see Fall 2015 Micro-World, pp. 328–329.

	Figure 2. The use of a red contrast filter with transmitted light (left) dramatizes growth textures, making them easier to study than with unfiltered transmitted light (right) while creating an aesthetically pleasing image. Photomicrograph by John I. Koivula; field of view 4.0 mm. Source: GIA @topic:2


Title: Windmill Zoning in Tourmaline Abstract: Colorless windmill-shaped zoning in tourmaline, as seen with diffused light. Photomicrograph by Britni LeCroy; field of view 9.60 mm.

Tourmaline often displays color zoning. Popular examples include parti-color tourmaline (color zoning perpendicular to the c-axis) and watermelon tourmaline (pink and green color zoning parallel to the c-axis). A more peculiar type of abundant colorless zoning with windmill structures (see above) was seen by the author in an 8.55 ct pink faceted tourmaline. The table was cut perpendicular to the length of the crystal to reveal the windmill zoning as parallel to the c-axis, terminating at the crown and pavilion. This characteristic was visible with or without the use of a microscope. However, diffused transmitted light was necessary for observation in both cases. The stone did not possess any other visible inclusions, but some areas showed fully formed colorless hexagonal zoning following the c-axis. This feature bore a mild resemblance to windmill inclusions seen in sphalerite (Summer 2020 G&G Micro-World, p. 295). Source: GIA @topic:2


Title: Elongated Rutile Crystal in Blue Sapphire from Afghanistan Abstract: The elongated orange transparent rutile crystal observed in the faceted blue sapphire from Afghanistan. Photomicrograph by Nattida Ng-Pooresatien; field of view 3.0 mm.
Rutile, titanium dioxide (TiO2), is a tetragonal mineral that generally occurs in corundum as silk (exsolution-formed needles), dust-like exsolution particles, or macroscopic crystal inclusions. Rutile crystals can have orange to deep red-brown coloration, and the crystal shapes can be rounded or euhedral.
The author recently examined a 4.24 ct faceted transparent blue sapphire from Afghanistan. The stone contained dusty flake-like inclusions, naturally healed fractures, lathe-like inclusions, twinning, rounded colorless crystals identified as apatite (RRUFF R040098), and an unusual long prismatic orange crystal identified as rutile (RRUFF R040049). This rutile crystal shape (see above) is not typical for corundum, particularly in blue sapphire. Source: GIA @topic:3


Title: Unknown Dendritic Inclusions in Sapphire Abstract: Left: When the pinkish purple sapphire was viewed under darkfield illumination, the only inclusions visible underneath the table were zircon crystals and rutile needles. Right: Examining the same area with fiber-optic light revealed unknown dendritic inclusions. Photomicrographs by Ezgi Kiyak; field of view 2.90 mm.
The authors recently examined a 4.03 ct light pinkish purple unheated sapphire. When viewed under darkfield illumination, the inclusion scene at first seemed fairly vacant and occupied only by sparse zircon crystals and rutile needles (see above, left). However, microscopic observation with fiber-optic light revealed large, delicate dendritic inclusions underneath the table (see above, right) that resembled a fern frond. The dendritic inclusions seemed to be flat and parallel to each other and extended the entire length of the table. Small round platelets were associated with the “branches” of the inclusions.
Further examination with a polariscope and conoscope helped prove that the dendritic inclusions were oriented parallel to the basal plane of the host corundum. A distinct uniaxial interference pattern was observed when viewing these inclusions from a perpendicular angle. The thinness and relative distance to the surface of the stone made it difficult to identify the inclusions with Raman spectroscopy. This is the first example of such dendritic inclusions in sapphire the authors have observed. However, a similar inclusion has been observed previously in a heat-treated blue sapphire (see Spring 2007 Lab Notes, pp. 54–55). Source: GIA @topic:3


Title: Parisite in Colombian Quartz Abstract: These three crystals captured in Colombian rock crystal quartz host three crystal morphologies of the rare mineral parisite: bipyramidal, hexagonal tabular prism, and pyramidal forms. Photomicrograph by Jonathan Muyal; field of view 4.79 mm.

	The brownish rare earth carbonate parisite is known as an unusual Colombian mineral specimen, and as a diagnostic inclusion indicative of Colombian origin when observed in emeralds (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gems, Vol. 1, ABC Edition, Zurich, 1986, p. 252). This rare mineral has also been reported to occur in quartz from Muzo, Colombia (E.J. Gübelin and J.I. Koivula, Photoatlas of Inclusions in Gemstones, Vol. 2, Opinio Verlag, Basel, Switzerland, 2005, p. 621).

	A particularly striking example of rock crystal quartz with numerous brown crystals of parisite was recently examined at GIA’s Carlsbad laboratory, where the inclusions’ identity was confirmed by Raman analysis. Interestingly, three of the most prominent parisite inclusions in this rock crystal quartz displayed multiple crystal habits: a well-formed bipyramid, a tabular hexagonal prism, and a pyramidal form. Due to their euhedral nature, these inclusions are presumed have formed simultaneously with their host quartz and are therefore termed syngenetic. Also present in the stone were numerous fluid inclusions and an iridescent interface on the bipyramidal crystal.

	This is the finest example of parisite as an inclusion in quartz that has been documented by GIA. Source: GIA @topic:2