# Publication Year: 2018
# Title: Cat's-Eye Demantoid and Brown Andradite with Horsetail Inclusions
# Abstract: Figure 1. This 2.51 ct green demantoid with chatoyancy (left) contained well-aligned fibers of horsetail inclusions (right, field of view 1.10 mm). Photos by Shunsuke Nagai (left) and Taku Okada (right).
Two garnets were recently submitted to the Tokyo lab for identification. One was a green cabochon weighing 2.51 ct; the other was an orangy brown round brilliant weighing 2.47 ct. Both had a refractive index (RI) over the limits of the refractometer and a hydrostatic specific gravity (SG) of 3.84. To confirm the identification, we used Raman spectroscopy. Both stones matched the andradite garnet group from the reference database. The ideal chemical formula of andradite is Ca3Fe2Si3O12. The most important feature in both garnets was their horsetail inclusions. The presence of horsetail inclusions, which are thought to consist of chrysotile fibers branching out and radiating toward the surface from a small chromite nodule, has been regarded as diagnostic for natural demantoid.

The 2.51 ct stone was a rare cat’s-eye demantoid (figure 1). Demantoid garnet is by definition the green-colored andradite caused by chromium substitution. Chatoyancy is usually caused by closely spaced bands of long, thin parallel needles or fibers in the correct orientation, with a polished rounded surface such as a cabochon to reflect the light off the parallel inclusions. In this stone, the chatoyancy was due to the fibers of the horsetail inclusions. The radiating fibers were not parallel straight lines but parallel curves, so the “eye” was slightly curved.

Figure 2. This 2.47 ct orangy brown andradite (left) contained radiating horsetail inclusions regarded as exclusive to demantoid (right, field of view 1.60 mm). Photos by Shunsuke Nagai (left) and Taku Okada (right).
The 2.47 ct stone was an andradite garnet with classic horsetails (figure 2). The dominant bodycolor was brown. The gemological properties and chemistry were classified as andradite in the garnet solid solution, but it was poorer in calcium and richer in iron and silicon than the ideal andradite composition. The brownish cast was due to iron. On occasion we encounter stones with a strong yellow component that still have enough green to qualify as demantoid. However, this stone had no green in it and therefore was just andradite, not demantoid.

Consequently, the horsetail inclusions cannot be considered exclusively diagnostic for demantoid. They may also be found in non-green andradite. These two identifications—“cat’s-eye demantoid” and normal “andradite” in spite of horsetail inclusions—were issued for the first time in GIA’s colored stone report records. @chapter:8 @chapter:0 @chapter:8


# Publication Year: 1997
# Title: Gemological Properties of Near-Colorless Synthetic Diamonds
# Abstract: Examination of 51 colorless to near-colorless synthetic diamonds from all known sources of production confirms that they can be distinguished from similar-appearing natural diamonds on the basis of their gemological properties. Although some may contain opaque metallic inclusions, the most distinctive feature of near-colorless synthetic diamonds is their luminescence to ultraviolet radiation and to an electron beam (cathodoluminescence). In particular, almost all fluoresce yellow or yellow-green to short-wave UV and, when the ultraviolet lamp is turned off, they continue to phosphoresce for 60 seconds or more. These distinctive reactions to ultraviolet radiation are very useful in identification, because many diamonds can be checked at one time. @chapter:29 @chapter:1 @chapter:29


# Publication Year: 2014
# Title: Titanium-Coated Tanzanite
# Abstract: Figure 1. These five tanzanite samples (0.39–0.82 ct) proved to be color-coated with titanium. Photo by Don Mengason.

Five faceted violetish blue stones, ranging from 0.39 to 0.82 ct (figure 1), were recently submitted to the Carlsbad laboratory for identification service. Standard gemological testing revealed a refractive index of 1.689–1.700 for all five samples. When observed using polarized light, each displayed a medium pleochroism. Specific gravity, measured using the hydrostatic method, was 3.37. These properties were consistent with tanzanite.

Figure 2. This upper portion of a pavilion facet, examined in reflected light, shows a much higher luster than the lower, uncoated portion. Photo by Nathan Renfro; field of view 1.22 mm.

Figure 3. The coating on this tanzanite’s pavilion has been worn away along the facet junctions and in some small chipped areas, revealing the less-saturated violet color of the tanzanite underneath. Photo by Nathan Renfro; field of view 2.90 mm.
Microscopic examination showed that the material was relatively free of inclusions, but showed areas of abrasion along pavilion facet junctions. Observed using reflected light, the pavilion of each stone showed a significantly higher luster than the crown. Some individual facets even showed a variation in luster due to an unevenly distributed color coating (figure 2). When the samples were examined using diffuse transmitted light, the facet junctions and several chipped spots appeared much less saturated, which was also consistent with a color coating (figure 3).

Because tanzanite with a cobalt coating has previously been reported (S.F. McClure and A.H. Shen, “Coated tanzanite,” Summer 2008 G&G, pp. 142–147), all tanzanites submitted to the lab are routinely checked by energy-dispersive X-ray fluorescence (EDXRF) and microscopic examination. These five stones were also checked by EDXRF, but no cobalt was detected; however, all five showed a significant signal for titanium on their pavilions. No titanium was detected on the crowns. LA-ICP-MS was also used to confirm that the coated area contained significant titanium.

While color-enhancing coatings on tanzanite are occasionally seen at GIA’s laboratory, this is the first time we have examined tanzanite that has been color coated with titanium. @chapter:7 @chapter:0 @chapter:7


# Publication Year: 2022
# Title: Tucson 2022 Overview
# Abstract: Figure 1. Customers select goods at the AGTA GemFair. Photo by Tao Hsu.
Sellers and buyers alike were delighted to be back at Tucson for the show season after a two-year absence. As the world enters a new phase of the pandemic, the gem and jewelry industry is also preparing for the post-pandemic era. Attendees embraced precautions such as social distancing and face coverings (figure 1). Although social gatherings were much less crowded than usual, the atmosphere and business at the shows were as strong as before, if not better.
Due to travel restrictions, the international presence was down, but that did not affect vendor attendance at the main AGTA GemFair at the Tucson Convention Center, where the majority of exhibitors had strong U.S. representation. The Gem & Jewelry Exchange (GJX) show was slightly affected, with some booths left empty by foreign dealers who could not make it to Tucson this year. Vendor attendance in the satellite shows outside of the convention center area remained strong, as observed by the authors at the Pueblo Gem & Mineral Show, the Kino Gem & Mineral Show (figure 2), and the 22nd Street Mineral, Fossil, Gem & Jewelry Show.

Figure 2. A stone decor dealer’s booth at the Kino Gem & Mineral Show. Open to the public, the show saw steady foot traffic. Photo by Tao Hsu.
Many exhibitors felt that while foot traffic was lighter than usual, buyers were focused on purchasing targeted goods to restock inventory. Meanwhile, the pandemic’s influence on the supply side of the value chain was just starting to show. Therefore, this Tucson show season provided a very good opportunity to prepare for a potential shortage in the coming months (figure 3).

Figure 3. Left: The Pueblo Gem & Mineral Show was an ideal place to source rough gems of all kinds. Right: Cutting services were provided at multiple shows open to the public. Photos by Tao Hsu.
The variety of gems and jewelry traded at the shows remained consistent with previous years. The “big three”—ruby, sapphire, and emerald—still dominate the market (figure 4), with the intake at the GIA Show Service Lab reflecting this. Collector minerals and gems such as meteorite, gahnospinel, fluorite of various colors, opalized fossils, cerussite, and colemanite continued to attract a niche market clientele (figure 5). Also in high demand were fantasy cuts, rose cuts, briolettes, and mineral or rock slices. Jewelry designers on a mission to fulfill special orders sourced gems such as Montana sapphire, Oregon sunstone, Arizona turquoise, Washington nephrite jade, and other American gems.

Figure 4. An 8.23 ct star ruby cut by David Nassi. Photo by Robert Weldon; courtesy of 100% Natural Ltd.

Figure 5. A 45 ct green fluorite from New Mexico. Dealers carried fluorite of all colors and cutting styles at both the AGTA and GJX shows. Photo by Emily Lane; courtesy of Barker & Co.
Vendors have never been more creative in terms of their products and business savvy. To fulfill the ever-growing demand for one-of-a-kind creations, gem cutters, carvers, and jewelry manufacturers have put more thought and individuality into their pieces (figure 6). Products manufactured with a high level of sophistication such as inlaid jewelry or gems were prominent at the show (figure 7). Many vendors have shifted more business online over the past two years to combat limited foot traffic in stores. Newly formed companies, meanwhile, have often started completely online or done most of their business online.

Figure 6. Left: Rock and metal wall decor in combination with metal art at the Kino show. Right: A 22.93 ct carved citrine crafted in Jaipur, India; courtesy of Artisav Jaipur. Photos by Tao Hsu.

Figure 7. Gemstone-inlaid bangles from David R. Freeland Jr. Designs at the Pueblo Gem & Mineral Show. Photo by Lisa Kennedy.
GIA relished in the much-anticipated return to Tucson this year, enthusiastically gathering the latest from the shows to share in this report. Our coverage includes market updates, interesting and noteworthy finds, and uplifting accounts from dealers, cutters, designers, and more.
The following contributed to this report: Erin Hogarth, Erica Zaidman, Robert Weldon, Albert Salvato, Wim Vertriest, Lisa Neely, and Nathan Renfro.

View Gallery

Photo Highlights from the 2022 Tucson Shows @chapter:42 @chapter:3 @chapter:42


# Publication Year: 2021
# Title: Eric Braunwart (Columbia Gem House)
# Abstract: Figure 1. Popular sapphire colors, including bicolor stones from Montana. These heated stones from the Gem Mountain, Missouri River, and Dry Cottonwood Creek areas are 4.0 mm in diameter. Photo by Dillon Sprague; courtesy of Columbia Gem House

              Eric Braunwart, founder of this gemstone mining, cutting, and wholesale marketing company, reported that they have stayed busy during the pandemic after the initial shock to business with the hard shutdown last spring. Columbia Gem House had already started transitioning three years ago to doing more business electronically. When the pandemic hit, they were well positioned to experience a less dramatic shift in how they interact with clients than some more traditionally run gem dealers. Mr. Braunwart sees the pandemic as having universally pushed people involved in all stages of the gem trade to do more of their business online.

Overall, Mr. Braunwart is happy with the way business is going but thinks that much of what he is experiencing has more to do with the clientele he has attracted and his move toward a strong digital platform. Currently, his customer base is part of what he considers the “new industry,” composed almost exclusively of women under 35 years old with independent stores, galleries, or studios. These buyers have grown up with smartphones and had already been doing business online but were pushed even further online with COVID-19. Columbia Gem House’s fair trade and responsibly sourced position in the marketplace resonates with this “new industry,” where these factors are an important part of the business models and branding and their clients’ lifestyles. Additionally, these buyers tend to purchase more unusual items with respect to color, cut, shape, and presence of inclusions.

Mr. Braunwart noted that the biggest disruption to the supply chain with COVID-19 has been at the mines, where mining has slowed with less travel and demand—greatly restricting the supply to wholesalers. This has particularly been the case with small miners who have not had travelers coming out to purchase at the traditional venues. This has pushed some small miners to explore selling online to reach some of the market and realize some of the markup that traditional cutters and wholesalers see. Gem cutting has also slowed significantly, with less rough coming out of the mines and restricted flow of goods crossing borders, due both to the pandemic and political issues. On a very somber note, COVID-19 has personally hit many small businesses along the supply chain, with some longtime miners, cutters, and traders dying from the disease.

When asked what has been in high demand this past year, Mr. Braunwart stated that sapphire is still the king in terms of volume and dollars. A variety of North American stones are still doing well and sales continue to increase. The recent increase in the desire to buy American continues, and now these products are more recognized in the marketplace. Demand for teal and other nontraditional sapphire hues remains very strong (figure 1). About half of the customers pursuing these nontraditional colors popularized by the sapphire mines in Montana want American sapphire, but the other half are concerned only about obtaining the desired colors and are buying material coming from Africa and Asia.

Figure 2. A variety of popular small-stone shapes such as kites, hexagons, trillions, and briolettes. All are heated Missouri River sapphires. The kites are either 6.0 × 4.0 mm or 5.0 × 3.0 mm, the hexagons are 3.5 mm in diameter, the trillions are 4.0 mm wide, and the briolettes are 4.0 × 3.0 mm and side-drilled. Photo by Dillon Sprague; courtesy of Columbia Gem House.
 A notable trend mentioned was the continued and increasing popularity of melee and smaller stones (baguettes, briolettes, trillions, kites, and hexagons; see figure 2). Both saturated and pastel hues of these smaller stones are in strong demand (figure 3).They are being used not only as accent stones but also as the main stones in many jewelry pieces. This reflects a growing fashion direction where more affordable pieces can be made using both precious gemstones and precious metals. Mr. Braunwart mentioned a shortage in 1.0–1.3 mm melee, as this size is very difficult to cut and mines traditionally do not collect the small rough that would produce these sizes. This means that melee in these sizes are coming from larger rough and scraps.

Figure 3. Melee and small sizes of fire opal and neon green beryl. The fire opals are from Mexico and range from 0.10 to 0.20 ct. The neon green beryl material is from Nigeria—the rounds are 3.0 mm in diameter and the baguettes are 4.0 × 2.0 mm. Photo by Dillon Sprague; courtesy of Columbia Gem House. @chapter:42 @chapter:3 @chapter:42


# Publication Year: 2023
# Title: Rainy Lakeside City in Peridot
# Abstract: Blade-like magnetite inclusions developed from a healed fracture in a 2.08 ct Burmese peridot resemble a rainy lakeside city. Photomicrograph by Makoto Miura; field of view 1.06 mm.
Inclusions in gemstones provide useful information regarding their geological origin. A 2.08 ct Burmese peridot containing unique black blade-like inclusions developed from healed fractures (fingerprints), as shown in the figure above. Raman spectroscopy identified these blade-like inclusions as magnetite. Tiny raindrop-like magnetite lamellae were also observed throughout the stone. Such inclusions in Burmese peridot sometimes create four-rayed asterism. According to previous studies, the presence of magnetite lamellae suggests the oxidation or dehydration of olivine by geological processes. This image resembles a rainy lakeside city landscape. @chapter:14 @chapter:0 @chapter:14


# Publication Year: -
# Title: GIA's Gübelin Gem Project: Zircon
# Abstract: Zircon
Photo by Robert Weldon/GIA, courtesy Dr. E. J. Gübelin Collection
GIA Collection 33723

Although colorless when chemically pure, zircon is typically yellow-brown to brown. It also comes in red, blue, purple, and green. Because of its high brilliance and dispersion, colorless zircon has sometimes been used as a substitute for diamond in jewelry.

33703

			5.76 ct Zircon
			Cambodia (PDF)

33723

			6.61 ct Zircon
			Cambodia (PDF)

33698

			11.58 ct Zircon
			Laos (PDF)

35605

			2.01 ct Zircon
			Madagascar (PDF)

35602

			7.36 ct Zircon
			Madagascar (PDF)

35601

			7.66 ct Zircon
			Madagascar (PDF)

34640

			10.40 ct Zircon
			Myanmar (PDF)

34669

			14.37 ct Zircon
			Myanmar (PDF)

34671

			16.32 ct Zircon
			Myanmar (PDF)

33734

			6.21 ct Zircon
			Sri Lanka (PDF)

33717

			7.11 ct Zircon
			Sri Lanka (PDF)

33705

			10.72 ct Zircon
			Sri Lanka (PDF)

33729

			11.77 ct Zircon
			Sri Lanka (PDF)

34920

			12.66 ct Zircon
			Sri Lanka (PDF)

34958

			16.65 ct Zircon
			Sri Lanka (PDF)

33699

			24.24 ct Zircon
			Sri Lanka (PDF)

33756

			8.74 ct Zircon
			Tanzania (PDF)

34341

			12.81 ct Zircon
			Tanzania (PDF)

35070

			21.05 ct Zircon
			Tanzania (PDF)

35091

			4.06 ct Zircon
			Thailand (PDF)

33719

			11.48 ct Zircon
			Thailand (PDF)

35092

			15.13 ct Zircon
			Thailand (PDF)

33746

			19.31 ct Zircon
			Thailand (PDF)

33694

			22.15 ct Zircon
			Thailand (PDF)

33695

			28.15 ct Zircon
			Thailand (PDF) @chapter:4 @chapter:0 @chapter:4