# Publication Year: 2014
# Title: Aquamarine with Unusually Strong Dichroism
# Abstract: Figure 1. This 4.49 ct grayish blue aquamarine was unusual for its strikingly intense dichroism. Photo by Gagan Choudhary.

Recently, a transparent grayish blue oval mixed cut (figure 1) was submitted for identification at the Gem Testing Laboratory in Jaipur. The 4.49 ct stone (12.04 × 8.88 × 7.53 mm) was relatively clean to the unaided eye. Its RI of 1.582–1.590, birefringence of 0.008 with a uniaxial negative optic sign, and hydrostatic SG of 2.71 suggested a beryl, which we later confirmed with FTIR and Raman spectroscopy. The specimen’s natural origin was established by planes of dendritic platelets (usually ilmenite) oriented along the basal plane and liquid fingerprints.

The stone’s most striking feature was its unusually strong dichroism, displaying deep blue and pale bluish green colors (figure 2). The deep saturated blue resembled that of a top-quality sapphire. Such strong dichroism was reminiscent of Maxixe-type (irradiated) beryls, although their dichroic colors are usually deep blue and colorless. The deep saturated blue was seen along the e-ray, the pale bluish green along the o-ray. Such a pattern of color absorption is associated with aquamarine; the opposite effect occurs in Maxixe-type beryl, which appears colorless along the e-ray and deep blue along the o-ray (R. Webster, Gems, 5th ed., Butterworth-Heinemann, London, 1994, pp. 124–127).

Figure 2. The dichroic aquamarine displayed unusually intense dichroism, with a deep saturated blue along the e-ray (left) and a pale bluish green along the o-ray (right). The images were taken by fixing the polarizing filter on the camera lens and rotating the polarizer 90 degrees to separate out the two directions. Photos by Gagan Choudhary.
Further analysis was performed with UV-Vis-NIR spectroscopy to confirm the cause of color and differentiate between aquamarine and Maxixe-type beryl. Polarized spectra (figure 3) revealed an absorption peak at approximately 427 nm along the o- and e-rays, a typical feature in aquamarine due to the presence of ferric iron (see I. Adamo et al., “Aquamarine, Maxixe-type beryl, and hydrothermal synthetic blue beryl: Analysis and identification,” Fall 2008 G&G, pp. 214–226); an additional peak at about 370 nm also occurred along the o-ray. No features associated with radiation-induced color centers were present between 500 and 700 nm; these are typically observed in Maxixe-type beryls.

Figure 3. The aquamarine’s polarized UV-Vis-NIR spectra displayed Fe3+-related bands at approximately 370 and 427 nm.
Standard gemological properties along with absorption spectra and the pleochroic color directions were sufficient to identify this stone as aquamarine. It displayed the most intense dichroism we have seen in an aquamarine. While there are deep sea-blue aquamarines (see O. Segura and E. Fritsch, “The Santa Maria variety of aquamarine: Never heated,” InColor, No. 23, 2013, pp. 34–35) as well as deep blue Maxixe-type beryls, this was the deepest blue we have observed in an aquamarine with a grayish blue hue. @chapter:19 @chapter:0 @chapter:19


# Publication Year: 2019
# Title: Trapiche Emerald from Colombia
# Abstract: Figure 1. Colombian emerald crystal with prismatic habit; in the orientation shown, the sample measures 15.4 × 5.2 mm. A: View perpendicular to one of the six prism faces, transmitted light. B: Schematic drawing of the crystal in the same orientation. Three prism faces m are observed. In a view through the central face (green), a cross formed by four boundaries is seen (red lines); in a view through the two adjacent faces (blue), two boundaries are observed (black lines). Photo by K. Schmetzer.
Colombian trapiche emeralds, in general, consist of a transparent or nontransparent tapered core and six transparent prismatic growth sectors, which are separated by nontransparent boundaries. These boundaries form the arms of a six-rayed fixed star and radiate from a central point or a central area within the conical core. The tapered core is also designated a basal or pinacoidal growth sector. The boundaries consist of emerald, various minerals (e.g., calcite and albite), and trapped fluid phases.
In the gem trade, trapiche emeralds are mostly cut as slices or cabochons with an orientation perpendicular to the sixfold axis of the emerald to show the hexagonal growth pattern of the gemstone and especially to display the six-rayed fixed star. The conical shape of the core is derived from the different diameters of the core on both sides of such a cabochon. Slices of trapiche emeralds with an orientation parallel to the c-axis clearly show a tapered core, representing the basal growth sector, and a rim on both sides of the core formed by two prismatic growth sectors. However, because rough trapiche emerald specimens are mostly broken on both ends, the complete trapiche pattern parallel to the c-axis is not observed, and even textbooks dealing with Colombian emeralds show only sketches or photos of crystal fragments.
Recently, a complete outline of a trapiche emerald pattern consisting of two pinacoidal (basal) and six prismatic growth sectors was presented by I. Pignatelli et al. (“Colombian trapiche emeralds: Recent advances in understanding their formation,” Fall 2015 G&G, pp. 222–259), but only fragments of trapiche crystals sliced parallel to the c-axis were available for that study. Consequently, the present author took the opportunity to examine the pattern in a transparent sample which, on a first view, seemed to be a complete or almost complete trapiche emerald crystal. The emerald was submitted by collector Georg Sellmaier (Kranzberg, Germany), who purchased the sample about 10 years ago from a local dealer while traveling in the Muzo area of Colombia.
The 3.49 ct emerald crystal (figure 1A) shows a prismatic habit with six elongated prism faces m (1010) and is terminated on one end by a basal pinacoid c (0001) and six small hexagonal dipyramids p (1012). Most likely, at the second termination of the crystal a facet approximately in the direction of a basal pinacoid was cut because the sample was slightly broken or did not show a plane face. The length of the crystal is 15.4 mm, while the diameter between the prism faces is 4.6 mm and the diameter between the crystal edges is 5.2 mm. Its pleochroism is blue-green parallel to the c-axis and yellow-green perpendicular to the c-axis.

Figure 2. A and B: View in immersion through the emerald crystal in two orientations related by a rotation of 60° along the c-axis; two prism faces are parallel to the direction of view. The pattern observed consists of a cross subdivided by a vertical line. C: Diagram of the crystal; a view through each of two prism faces m (blue and green) shows two boundaries (red lines). These boundaries form an X, also subdivided by a vertical boundary (yellow line). Photos by K. Schmetzer.

Figure 3. View in immersion of the emerald crystal in a direction oblique to the c-axis. A tapered central core is seen, formed by six plane boundaries between a basal and six prismatic growth sectors; the diameter of the crystal in this view measures 5.2 mm. Photo by K. Schmetzer.
In an orientation where the crystal is resting on one of the six prism faces (i.e., in a view perpendicular to this face), three different prisms are seen. In a view through the central prism, a cross in the form of an X was observed, with a pattern described as part of such a cross seen also in views through the two other adjacent prism faces (again, see figure 1A). A schematic drawing of this situation is presented in figure 1B. In the immersion microscope, upon rotation of the emerald crystal along its hexagonal axis, in each view parallel to two of the six prism faces (i.e., rotated by 30° versus the view perpendicular to a prism as described above and depicted in figure 1), a pattern consisting of a sharp cross is seen, with a vertical line dividing the cross into two parts (figure 2, A and B). The schematic drawing in figure 2C reflects this situation. In a view oblique to the c-axis, a tapered cone formed by six plane boundaries is seen at both ends of the crystal (figure 3). In a view parallel to the c-axis, due to the length of the crystal and the various layers covered with inclusions present throughout the crystal, the sample is only translucent, but a pattern of a six-rayed fixed star is observed.

Figure 4. A: The patterns seen through the prism faces in different orientations of the emerald crystal are formed by boundaries between six different prismatic growth sectors (red, only three growth sectors are shown) and the two pinacoidal growth sectors, and boundaries between adjacent prismatic growth sectors (yellow). B: The outline of the tapered core is formed by the boundaries between six prismatic growth sectors (red) and two pinacoidal growth sectors.
It is evident that the various lines forming crosses in the form of an X are the traces of plane boundaries between the two pinacoidal and the six prismatic growth sectors. The vertical lines that subdivide these crosses in the second orientation described here represent boundaries between the six prismatic growth sectors (see figures 1B, 2C, and 4A). The cone-shaped outline of each pinacoidal growth sector is formed by boundaries between the tapered core and six prismatic growth sectors (figure 4B). The different patterns depend only upon the orientation of the crystal in the direction of view and the orientation of the various boundaries between the six prismatic and two basal growth sectors within the emerald.
The crystal described represents an almost complete emerald with prismatic habit and trapiche pattern. In the present case, the trapiche pattern is similar to an hourglass structure. However, the trapiche emerald shows numerous inclusions that are trapped at the boundaries between different growth sectors, forming thin layers. As described in the literature, these layers between the individual emerald growth sectors consist of a mixture of emerald with other minerals and fluid phases trapped in cavities. In contrast to most trapiche emeralds from Colombia, the layers in the emerald described in this paper are thinner and translucent, which allows an observation of the complete three-dimensional trapiche pattern, especially in views perpendicular to the c-axis. This observation is consistent with the conclusion made by several authors about the cone-shaped cores of trapiche emeralds and confirms the three-dimensional model of the trapiche pattern presented by Pignatelli et al. (2015). @chapter:10 @chapter:0 @chapter:10


# Publication Year: -
# Title: Summer 2010 Gem News International
# Abstract: Diamonds
	            Unusual Facet Arrangement Produces Scalloped Appearance in Diamond
Colored Stones and Organic Materials
	            Chrysocolla Chalcedony from Acari, Peru
	            Recent Finds Of Kunzite in Pala, California
	            Natural Pearls of the Pectinidae Family: Review and Origin of Color
	            More on Ruby from Cabo Delgado, Mozambique
	            Ruby, Sapphire, and Spinel Mining In Vietnam: An Update
	            Sphene from Northern Pakistan
	            Spinel from Bawma, Myanmar
	            Tsavorite and Other Green Garnets Reportedly from Afghanistan
Synthetics and Simulants
	            An Unusual Lab-Grown Garnet: Calcium Niobium Gallium Garnet
	            Glass Imitations of Emerald with Straight Zones
	            “Nanogems”—A New Glass-Ceramic Material
	            Serpentine Doublets, Sold as Pietersite, from Arizona
Treatments
	            A Composite Coral Bangle
	            Lead Glass-Filled Ruby in Antique Jewelry
	            Tanzanite and Other Gems Set with Colored Adhesive
Conference Reports
	            1st Italian Conference on Scientific Gemology
	            Sinkankas Symposium 2010—Gem Feldspars
Miscellaneous
	            Gem News from Myanmar
Announcements
	            Updated CIBJO Blue Books Released
In Memoriam
	            Roy E. “Chip” Clark (1947-2010), scientific and studio photographer

To view the full section, download the PDF above.

	DATA DEPOSITORY

Supplementary Information and Photos
	Submitted by Mark Mauthner
	July 31, 2010 @chapter:1 @chapter:0 @chapter:1


# Publication Year: 2022
# Title: Spring 2022 Auction Highlights
# Abstract: Figure 1. At 228.31 ct, the Rock is the largest white diamond ever sold at auction. Photo courtesy of Christie’s.
The De Beers Cullinan Blue was the early buzz of the spring 2022 auction season, with the 15.10 ct Fancy Vivid blue step-cut diamond far surpassing Sotheby’s presale estimate of $48 million. Bringing $57.5 million, the diamond was the largest of its color to ever appear at auction and also the third most valuable diamond of any color to sell at auction. (To read more about GIA’s examination of the De Beers Cullinan Blue, see Lab Notes in this issue, pp. 216–217.)
The season continued in Geneva, with Christie’s auctioning two diamonds weighing more than 200 ct each at the Magnificent Jewels sale on May 11, beginning with the largest white diamond ever sold at auction. Named the Rock (figure 1), the GIA-graded 228.31 ct, G-color, VS1 pear-shaped diamond sold for $21.9 million, or $96,000 per carat. The previous record holder for the largest white diamond sold at auction weighed 163.41 ct and was sold by Christie’s in 2017.

Figure 2. The 205.07 ct Red Cross diamond set an auction record price for a Fancy Intense yellow diamond at Christie’s Geneva Magnificent Jewels sale. Photo courtesy of Christie’s.
The second diamond, the Red Cross (figure 2), returned to Christie’s for a third time at auction. It was first sold at Christie’s in 1918 to benefit the British Red Cross during World War I. At 205.07 ct, the GIA-graded Fancy Intense yellow cushion cut fetched $14.3 million, or $70,000 per carat, after 11 minutes of competitive bidding, setting an auction record price for a Fancy Intense yellow diamond. A portion of the proceeds benefited the International Committee of the Red Cross.

Figure 3. This necklace featuring 33 jadeite beads was the top lot at Christie’s Magnificent Jewels sale in Hong Kong. Photo courtesy of Christie’s.
A jadeite necklace (figure 3) was the top lot at Christie’s May 25 Hong Kong sale, selling for $8.8 million after 11 minutes of bidding. The stunning piece features 33 perfectly round, exceptionally large jadeite beads ranging from 12.3 to 15.0 mm in diameter, with an 11 ct Burmese ruby clasp surrounded by oval brilliant diamonds.

Figure 4. The 103.49 ct Light of Africa diamond sold for an impressive $195,000 per carat at Christie’s Magnificent Jewels sale in New York. Photo courtesy of Christie’s.
In June, the focus returned to diamonds at Christie’s final Magnificent Jewels auction of the season in New York. The 103.49 ct Light of Africa (figure 4), the fifth most valuable colorless diamond ever offered at Christie’s, surpassed its presale estimate of $18 million, with the winning bid coming in at just over $20 million—an incredible $195,000 per carat. The GIA-graded emerald-cut type IIa diamond was cut and polished from a 299 ct rough stone unearthed from the Cullinan mine. @chapter:37 @chapter:3 @chapter:37


# Publication Year: 2020
# Title: Gem Carvings, Fantasy Cuts, and Master Recutting
# Abstract: Figure 1. Left: Nick Alexander exhibits a selection of his work. Photo by Jennifer Stone-Sundberg. Right: A 64 ct fantasy cut amethyst from Bahia, Brazil. Photo by Kevin Schumacher; courtesy of Nick Alexander, Alexanders Jewelers.
This year at the AGTA show, the number of booths selling skillfully carved, fantasy cut, or expertly recut items was noticeably higher than in past years. These forms of working rough or previously cut material are a way to add significant value and desirability to material that might otherwise be cut into standard shapes or with the intent to maximize weight at the expense of beauty.

	Gem carver Nick Alexander

Nick Alexander (figure 1, left) of Alexanders Jewelers in Gilbert, Arizona, was exhibiting his work for the first time at the AGTA show. This year, Mr. Alexander won second place in the carving category of the AGTA Cutting Edge Awards with his 42.05 ct Oregon sunstone piece at the impressive age of 17. A favorite material of his is electric blue gem silica from the Ray mine in Arizona (see figure 2 in the Tucson Overview). Mr. Alexander is also skilled at fantasy cutting with materials such as amethyst (figure 1, right) and beryl.

Figure 2. A 322.72 ct Madagascar rose quartz lotus flower carving with grayish blue and padparadscha Montana sapphires in the center (5.56 and 0.65 ct, respectively), shown by the artist, Glenn Lehrer. Left photo by Robert Weldon/GIA, courtesy of Glenn Lehrer; right photo by Jennifer Stone-Sundberg.
One of the carvers who has inspired Mr. Alexander, Glenn Lehrer of Larkspur, California (figure 2, right), was also at the AGTA show. Mr. Lehrer shared with us one of his newest works, an exquisite lotus flower carved out of a top-quality rose quartz from Madagascar (figure 2, left). This piece started as part of a museum collection project with designer Paula Crevoshay. It took two years to find the 3.8 kg rose quartz rough meeting his stringent demands: It had to be clean, clear, and with strong color. The finished carving measures 79.5 × 69.8 mm and weighs 322.72 ct. To complement the piece, the center features two sapphires from the Rock Creek area of Montana: a 5.56 ct grayish blue “torus ring” carving and a 0.65 ct padparadscha.

Figure 3. Left: David Nassi of 100% Natural, Ltd. showing a collection of unheated spinels he has recut, ranging in size from 7.10 to 18.53 ct. Photo by Jennifer Stone-Sundberg. Right: A 14.49 ct cat’s-eye alexandrite from Sri Lanka cut by Nassi, showing reddish brown to green color change. Photos by Emily Lane; courtesy of David Nassi.
Master gem cutter David Nassi from New York City (figure 3, left) showed us an impressive set of unheated natural spinels and several other gems he had recut to maximize color and light return. Of particular interest was a phenomenal gem, a natural color-change cat’s-eye alexandrite (figure 3, right) that was polished to a double-sided cabochon to display the cat’s-eye effect on both sides of the stone. Watch videos of David Nassi displaying his work:

	David Nassi displaying his recutting work @chapter:28 @chapter:2 @chapter:28


# Publication Year: 2024
# Title: Consumer Demand for Jewelry in the United States Market
# Abstract: Sales of jewelry in the United States market in 2566, based on data compiled by Grandview Research, amounted to approximately 73.32 billion US dollars. The top-selling products were necklaces, rings, earrings, bracelets, and others in descending order. This accounts for 20.76% of the global jewelry market. It is expected that the jewelry market in the United States will expand by an average of 4.1% between 2567-2573.

Factors driving consumer demand for jewelry in the United States market include:

1. Increased consumer willingness to spend: Consumers in the United States are becoming more confident in the economy, with growing incomes leading to increased spending. Data from the BEA shows a 0.8% increase in consumer spending on jewelry in March 2567 compared to the previous month. This indicates a positive signal for 2567, although economic uncertainties remain.

2. Fashion trends and changing preferences: Fashion trends and evolving preferences stimulate consumer purchases. Personalized jewelry, symbolic necklaces, and a blend of classic and sustainable materials appeal to consumers with diverse tastes and budgets.

The popularity of jewelry from influential and famous individuals on social media plays a significant role in creating more sales opportunities for sellers in the market. It also drives new trends and creates widespread popularity among consumers in the United States and globally. For example, the "iced out" trend, which involves decorating pieces of jewelry with diamonds to increase their sparkle, originated from the Hip Hop community and later expanded to athletes and then to a new generation of consumers in the United States and the broader fashion streetwear industry.

Furthermore, the influence of sustainability has played a significant role in the jewelry industry. It has encouraged designers to seek materials and production processes that support sustainability and environmental friendliness to better meet the current consumers' demands.

Based on data from King Jewelers, projected trends for women's jewelry in the coming year include jewelry adorned with contemporary, simple designs using pearls, multi-layered chain necklaces, flower-themed jewelry, large statement pieces, and animal-inspired designs.

As for men's jewelry trends, as projected by Gabriel & Co, they include meaningful pieces, jewelry decorated with rose gold, craftsmanship-focused designs or those featuring geometric patterns, classic jewelry pieces, chain-linked jewelry, pieces related to beliefs or culture, masculine-focused designs, pieces with metal tones, personalized jewelry, and wedding jewelry.

Consumer preferences for jewelry in the United States market:

3. Major festivals stimulate consumer purchases. Consumers in the United States often buy jewelry as gifts during significant festivals. According to data from National Jeweler, major festivals are the peak periods for jewelry sales. In terms of sales value during these festivals, Valentine's Day has the highest sales, followed by Mother's Day, Graduation Day, Wedding Day, and Christmas Day, respectively.

According to NRF data, during the recent Valentine's Day period, American consumers spent a total of $6.4 billion on jewelry purchases. However, for the upcoming Mother's Day festival on May 12, 2567 (2024), NRF forecasts that American consumers may spend around $7.0 billion on jewelry. Based on a survey of 8,213 adult American consumers conducted by NRF from April 1-8, 2567 (2024), it was found that 84% of the surveyed group planned to celebrate Mother's Day and spend an average of $254.04 per person. This surveyed group is expected to spend the most on flowers, followed by greeting cards, dining out, jewelry, spa services and pampering, and electronics, in that order. Additionally, the survey revealed that the key buying demographic consists of consumers aged 35-44, who plan to spend an average of $345.75 per person on Mother's Day products.

As for the distribution channels of jewelry products in the United States market, do you want me to provide information on that as well?
1. Online Channels
Statista forecasts that jewelry sales in the online system of the United States in the year 2567 (2024) are likely to expand by 26.2%. The key distribution channels can be divided into 4 main channels:

- Primary E-Commerce platforms such as Amazon.com, eBay.com, and Etsy.com
- Online auction platforms like Sothebys.com, Christies.com, Jewelry.ha.com, and Jewelry-auctioned.com
- Online retail stores like zales.com, kay.com, bluenile.com, jamesallen.com, brilliantearth.com, kohls.com, macys.com, etc. To sell through these retail channels, sellers need to apply through the respective store's page and fill out a form to become a supplier (become a supplier).
- Social media platforms like Facebook and Instagram, which are popular trends in the current era. Leveraging influencers on social media helps in product promotion and boosts sales figures.
2. Offline Channels
According to data compiled by Grand View Research, jewelry sales through offline channels in the United States in the year 2566 (2023) accounted for approximately 84% of total sales. Additionally, offline channels are highly popular for selling high-value jewelry or conducting significant jewelry transactions. This preference is due to buyers seeking trustworthiness and reliable post-sales services.

Key Offline Channels:

Department Stores and Specialty Stores**: These traditional retail outlets offer a range of products, including jewelry. Despite higher overhead costs, they often excel in other areas such as customer service and creating unique experiences. Services like in-person consultations, product inspections, repair services, and more contribute significantly to enhancing customer experiences and stimulating long-term purchases. However, offline stores may need to adapt further to compete with online retailers. This could involve curating unique designs, offering personalized product services, creating themed product sets for important occasions, and setting prices to be accessible to customers. Additionally, creating in-store experiences such as workshops, consultations, and leveraging digital tools like interactive displays or digital customer tools can help attract and engage customers more effectively.

New Trends in the US Market:

1. **Direct-to-Consumer (D2C) Sales**: This trend involves selling products directly from designers to consumers through online and social media channels. The focus is on unique designs in manageable quantities and competitively priced products. This method is popular for penetrating new markets for new brands or establishing memorable brands, especially targeting younger generations from Gen Millennials to Gen Alpha.

2. **Pop-Up Shops or Temporary Retail Stores**: These are temporary retail outlets set up by designers or distributors, emphasizing new trendy products in the market. They create a special experience for buyers while also serving as a way for designers and sellers to test market demand for their products.

3. **Membership-based Services**: These services offer carefully curated jewelry that matches buyers' needs on various occasions. It's suitable for customers looking for personalized shopping experiences and convenience. The membership approach gives customers the opportunity to try out new brands and designs that fit their preferences on different occasions.

Opportunities for Thai Products in the US Market:

The demand for materials changes according to market trends. Both the prices of metals and the availability of diamonds in laboratories have been significantly restricted. This has led manufacturers to adapt and choose alternative materials to make their products competitive in the market. For example, using soft gemstones or using standard-grade (K) metals with low carat and gold plating. These are good opportunities for Thailand in terms of production and export of such products to the US, providing them to importers.

Furthermore, after discussions with jewelry importers who have traveled to negotiate trade deals in Thailand, it was found that they mostly want to produce and import finished jewelry in the 14K and 18K gold categories embellished with diamonds and gemstones. Importers believe that if the US further escalates trade restrictions with China in the future, products mainly manufactured in China, including jewelry, will also be impacted. Therefore, companies have started looking for alternative sources, and Thailand seems to be a suitable and efficient production alternative. @chapter:32 @chapter:3 @chapter:32


# Publication Year: 2008
# Title: Summer 2008 Gem News International
# Abstract: Diamonds
            Bird-like Inclusion in Diamond
            A Colorless Diamond Showing Strong Phosphorescence
Colored Stones and Organic Materials
            Almandine-Spessartine from Lindi, Tanzania
            “Red Andesine” from China: Possible Indication of Diffusion Treatment
            Orange Beryl from India
            Chromium-Rich Clinochlore (Kämmererite) from Turkey
            Yellow Danburite from Tanzania
            Lawsonite from Marin County, California
            Green Mica (Paragonite) from Pakistan
            An Interesting Opal
            Engraved Black Cultured Pearls
Pinctada Maxima Cultured Pearls Grown Beadless in the Mantle
            Twinned Cultured Pearl
            Interplanetary Cat’s-Eye Peridot
            New Rubies from Central Tanzania
            Ruby and Sapphire Mining at Winza, Tanzania
            A Sapphire with En Echelon Inclusions
            Serpentinite Artifact Resembling Libyan Desert Glass
            Star and Cat’s-Eye Topaz from Brazil
            A New Source of Persian Turquoise: Kerman, Iran
            A Rare Faceted Yellow Vanadinite
Synthetics and Simulants
            Experimental CVD Synthetic Diamonds from LIMHP
            Unusual Glass Imitation of Rubellite
            Tourmalines and Their Imitations Obtained in Kandahar, Afghanistan
Conference Reports
            Sinkankas Garnet Symposium
            2008 Scottish Gemmological Association Conference
Announcements
            CIBJO Introduces Precious Metals Blue Book
Exhibits
            Exhibits at the GIA Museum
In Memoriam
            George S. Switzer (1915–2008), distinguished mineralogist

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


# Publication Year: 2021
# Title: Epoxy-Filled Chalcedony as an Imitation for “Candy Agate”
# Abstract: Figure 1. Rough stones of candy agate from the Alxa Plateau of Inner Mongolia are usually found in irregular shapes and granular gravels, as shown in this picture. Photo by Shu-Hong Lin.
A special kind of agate known as “candy agate” is produced in the Alxa Plateau of Inner Mongolia. This type of agate usually comes in irregular shapes and granular gravels, with a diameter ranging from several millimeters to several centimeters (figure 1). In addition to a variety of bodycolors, these agates occasionally present color zoning between the inner core and the outer layer. These candy agates have been very popular during the past few years, especially in the Taiwan market.

Figure 2. A string of beads submitted to TULAB as “candy agate.” Photo by Kai-Yun Huang.
Recently, several strings of beads were submitted to the Taiwan Union Lab of Gem Research (TULAB) as candy agate (figure 2). The outer layer of the beads was colorless and semitransparent, and the inner core presented various colors of green, purple, orange, yellow, or greenish blue. These agate beads did not have any fissures extending from the surface to the inner core but only a drill hole penetrating each bead so they could be threaded together to make a bracelet. Gemological testing identified the beads as chalcedony, but the unusually bright color of their inner cores looked unnatural and thus aroused suspicion.

Figure 3. The Raman spectra of the outer layer and the inner core of the beads matched those expected for chalcedony (K.J. Kingma and R.J. Hemley, “Raman spectroscopic study of microcrystalline silica,” American Mineralogist, Vol. 79, 1994, pp. 269–273) and epoxy resin (K.E. Chike et al., “Raman and near-infrared studies of an epoxy resin,” Applied Spectroscopy, Vol. 47, No. 10, 1993, pp. 1631–1635). The stacked spectra are baseline-corrected and normalized.

Figure 4. One bead showed a few bubble inclusions in its orange core. Photomicrograph by Shu-Hong Lin; field of view 3.06 mm.

Figure 5. A greenish blue bead cut in half revealed its drill hole (A), greenish blue epoxy filling (B), and colorless chalcedony (C). Photomicrograph by Yu-Shan Chou; field of view 2.83 mm.
To verify whether the center color of these beads was natural, the beads were further analyzed by Raman spectroscopy with 785 nm laser excitation at the surface and about 1–2 mm deep into the colored inner core. Comparisons of the resulting spectra with those reported in previously published studies identified the materials as chalcedony and epoxy resin (figure 3), which means that these “candy agates” were likely chalcedony beads hollowed out and filled with colored epoxy resin. Under microscopic observation (figure 4), some of the beads even had bubble inclusions in their inner cores, further supporting the possibility of epoxy filling. To understand how these beads were made, we asked the owner to provide samples cut in half for further testing. Microscopic observation of the cross-sections revealed that the beads were somehow hollowed out through the drill hole and then filled with colored epoxy resin (figure 5). Finally, a second drilling was performed along the original drill hole after the epoxy resin had hardened.
The colored inner core, which makes the agate special and valuable, is common in natural candy agate from the Alxa Plateau. The imitation candy agate in this study could be defined as a new type of epoxy-filled chalcedony which showed similar colored cores to natural candy agate. The most effective non-destructive methods for identifying this product are Raman spectroscopy and microscopic observation, but the results may be affected by the location of the inner core and the transparency of the chalcedony. @chapter:7 @chapter:0 @chapter:7


# Publication Year: -
# Title: 3-D Printing: GIA Equips Students for a ‘Technology Revolution’
# Abstract: Michelle Loon, a recent graduate of GIA’s Jewelry Design Technology program, holds the build platform containing the 3-D-printed resin prototypes of her jewelry design. Photo by Kevin Schumacher

                      Robert Downey Jr. presents an Iron Man-inspired, prosthetic 3-D-printed arm to a young fan. The “Pancake Bot” prints intricate, customized breakfast treats directly onto a griddle. Chinese construction company WinSun creates a five-story apartment building in Shanghai with a 500-foot long 3-D printer.

The incredible potential of 3-D printing is all over the news and our social media feeds. The applications are mind-boggling and their benefits game-changing for industries ranging from medicine to food to architecture – and to jewelry design and manufacturing, where time, precision and cost-effectiveness are highly valued.

These 3-D printing applications are part of a larger movement that has already begun to change the status quo, says Steve Workman, an instructor who uses the printers in GIA’s Jewelry Design and Technology (JDT) program.

		It’s [3D printing] the way the industry is going and it’s what every company wants, from huge manufacturers to the mom-and-pop stores.

		Kimberly Overlin, GIA’s dean of students

“Something remarkable happened to jewelry design and manufacturing in the past few years,” he says. “It underwent a technology revolution powered by Computer-Aided Design (CAD) software and Computer-Aided Manufacturing (CAM) hardware, such as 3-D printers.”

3-D Printing: What is It, Exactly?

As much as 3-D printing has made headlines, many people still don’t understand what it is or how it works. It can be helpful to consider the broader context of 3-D printing through the terms subtractive and additive manufacturing.

Imagine a Renaissance artist gazing at a huge slab or marble, considering how he might create art out of the rough stone. That’s how Mike Magee, the manager of GIA’s Jewelry Manufacturing Arts (JMA) program, likes to explain subtractive manufacturing.

“If you think of it as starting with a big block of something and whittling away until what you want is revealed – like Michelangelo looking at that marble and seeing what is living inside of it – that’s subtractive manufacturing,” he says.

Additive manufacturing, including 3-D printing, starts with nothing at all: It involves creating a piece of jewelry, a pancake, a prosthetic arm or an apartment building from the ground up, one tiny layer at a time.

“These layers are down to 30 microns thick, typically,” Magee says. “That’s 3/100ths of a millimeter, for perspective.”

The 3-D printers, a type of CAM hardware, use additive technology to print objects like chains or mesh directly into 18K gold.

“That’s still pretty rare in our industry, though,” Magee says. “In other industries it’s more developed, but this is still very new to the jewelry world. Most of the time with 3-D printing, we’re creating a model – an object that’s going to be cast – like a ring or larger object that doesn’t have quite so many moving parts, and we’re creating it in a material that works reasonably like wax when it comes to the casting process.”

GIA Instructor Steve Workman assists Jewelry Design Technology students in supporting their CAD models as they prepare them for building on the 3-D printer. Photo by Kevin Schumacher
More Efficiency and Accuracy, Less Waste

There’s no doubt that Michelangelo’s famous David is an artistic masterpiece, but the artist also wasted a lot of costly Tuscan marble every time he took a chisel to the block.

That’s one of the greatest benefits of utilizing 3-D printing or any additive technologies - there’s less material waste. CAD technologies already make it possible to more quickly create proofs of concept, precise mirror images, modifications and customizations. The new 3-D printers only enhance that.

“In the past, manufacturers used rubber molds to make duplicates of the original master model,” Workman says. “If variations on that model were needed, the model maker would have to create a whole new model. With CAD software, changes can be made with clicks of a mouse, and the new model can be printed on demand on a CAM machine such as a 3-D printer. These printers enable manufacturers to print resin prototypes of the CAD model that can be easily cast.”

Michelle Loon removes the build platform from the 3-D printer. Photo by Kevin Schumacher
Kimberly Overlin, GIA’s dean of students and an alumna of the Institute’s graduate gemology and graduate jeweler programs, notes that it makes the consumer trend of wanting to “customize everything” possible.

“What was once potentially cost-prohibitive is now affordable and easy for us to do,” she says.

Magee adds that a “much more effective economy of scale” is another significant benefit. Since a 3-D printer typically allows printing more than one object at time, a manufacturer could potentially print 16 rings in six to eight hours instead of one in the same time period.

As a form of additive manufacturing, 3-D printing also “has the advantage of being able to create much more complicated geometry than you get with subtractive manufacturing,” he says.

“You can create hollow spots much more easily. On most 3-D printers, you are not limited by the geometry of the piece itself - there are no tools to get into a hollow spot, there is no drill you have to get into a weird angle.”

Jewelry Design technology students compare the visual communications of their designs to the 3-D-printed and cast prototypes. Photo by Kevin Schumacher
Equipping Students with In-Demand Skills

GIA utilizes 3-D printing in its 26-week JDT program, offered in Carlsbad and, in 2016, at the Institute’s New York campus. The program, which teaches design, engineering and jewelry manufacturing concepts, gives students hands-on experience in the creation, rendering and prototyping of designs with CAD software and CAM hardware, including 3-D printers.

Instructors, including Workman, Shaun Peterson, Darla Alvarez, Doug Hall and Kelly Borrello begin with the basics.

“We start off with a very simple ring,” Magee says. “Students create very simple geometry and supports for that, and gradually create more and more complex geometry and have to support it and print those pieces, as well. Eventually, they’re designing their own pieces, and by the end of the program they’ve got the skills to look at any object and figure out how they’re going to get it to successfully print and cast.”

Laurie Bailyn, GIA’s manager of JMA research, development and production, says new markets are opening up all the time for these technologies.

“Some large corporations, like Hewlett-Packard and Autodesk, that weren’t previously in this market are expressing interest in developing hardware or software for 3-D printing in jewelry,” she says.

Overlin concurs.

“CAD/CAM technologies like 3-D printing have been moving into jewelry for the past several years,” she says. “It’s the way the industry is going and it’s what every company wants, from huge manufacturers to the mom-and-pop stores. There is a much greater need for qualified people who can utilize them – the more graduates know and the more marketable they are, the better.”

Magee expects that GIA graduates will be well-equipped to meet the challenges and opportunities of the ever-evolving design and manufacturing market.

“The jewelry design technology class is going to give you a front-row seat to the tremendous change that’s going on in our industry,” he says. “It’s going to give you experience with the latest 3-D printers, the latest in technology – and how that is changing the entire marketplace.” @chapter:45 @chapter:2 @chapter:45


# Publication Year: -
# Title: GIA's Gübelin Gem Project: Beryl
# Abstract: Beryls
Photo by Robert Weldon/GIA, courtesy Dr. E. J. Gübelin Collection
GIA Collection 33007, 34281, 34289, 34815, 34290, 25919, 34270, 35274, 35253, 33058, 32698

Chemically pure beryl is colorless, but trace elements give rise to green, blue and pink/red colors. The most important variety is green emerald (colored by chromium or vanadium), followed by blue aquamarine and yellow heliodor (both colored by iron) and pink morganite (colored by manganese). Some beryls fashioned as cabochons exhibit asterism (a star-shaped pattern of reflections) or chatoyancy (a “cat’s-eye” seen in reflected light).

33052

			7.62 ct Beryl
			Brazil (PDF)

33004

			23.35 ct Beryl
			Brazil (PDF)

33005

			36.38 ct Beryl
			Brazil (PDF)

34348

			3.05 ct Beryl
			Kenya (PDF)

34400

			15.48 ct Beryl
			Madagascar (PDF)

34815

			10.27 ct Beryl
			Sri Lanka (PDF)

35253

			13.82 ct Beryl
			Zimbabwe (PDF)

34268

			17.96 ct Beryl - Aquamarine
			Brazil (PDF)

33117

			8.87 Beryl - Aquamarine
			Kenya (PDF)

34398

			9.60 ct Beryl - Aquamarine
			Madagascar (PDF)

34496

			12.58 ct Beryl - Aquamarine
			Mozambique (PDF)

34554

			11.02 ct Beryl - Aquamarine
			Myanmar (PDF)

34703

			1.60 ct Beryl - Aquamarine
			Namibia (PDF)

35272

			7.78 ct Beryl - Aquamarine
			Zimbabwe (PDF)

33869

			0.44 ct Beryl - Emerald
			Colombia (PDF)

33860

			0.74 ct Beryl - Emerald
			Colombia (PDF)

33872

			3.51 ct Beryl - Emerald
			Colombia (PDF)

33876

			1.13 ct Beryl - Emerald
			Russia (PDF)

33001

			31.46 ct Beryl - Goshenite
			Sri Lanka (PDF)

33043

			8.41 ct Beryl - Heliodor
			Brazil (PDF)

34281

			14.44 ct Beryl - Heliodor
			Brazil (PDF)

33034

			14.67 ct Beryl - Heliodor
			Ukraine (PDF)

35274

			4.72 ct Beryl - Heliodor
			Zimbabwe (PDF)

33046

			11.46 ct Beryl - Heliodor
			Zimbabwe (PDF)

33028

			4.54 ct Beryl - Morganite
			Brazil (PDF)

34269

			15.72 ct Beryl - Morganite
			Brazil (PDF)

33003

			23.66 ct Beryl - Morganite
			Brazil (PDF)

33000

			100.99 ct Beryl - Morganite
			Brazil (PDF)

33030

			21.10 ct Beryl - Morganite
			Madagascar (PDF)

33031

			16.25 ct Beryl - Morganite
			United States (PDF)

35278

			5.14 ct Beryl - Morganite
			Zimbabwe (PDF)

33058

			1.03 ct Beryl - Red Beryl
			United States (PDF)

35171

			4.27 ct Beryl - Red Beryl
			United States (PDF) @chapter:5 @chapter:0 @chapter:5


# Publication Year: -
# Title: New Record Size for CVD Laboratory-Grown Diamond
# Abstract: Figure 1. The new record size for CVD laboratory-grown diamond—16.41 ct, with G color and VVS2 clarity—has been achieved by Shanghai Zhengshi Technology Co. Ltd. This is an as-grown diamond; no post-growth treatment was applied for color improvement, either before or after faceting. Photo by Towfiq Ahmed.
Growth technology of single-crystal diamond has advanced significantly in the last two decades, for both the high-pressure, high-temperature (HPHT) and chemical vapor deposition (CVD) methods. In addition to many other applications, laboratory-grown diamonds have become an expanding segment of the jewelry industry. Records for crystal size and quality are frequently broken. In this note, GIA’s New York laboratory reports on a new record for CVD laboratory-grown diamond.
This princess-cut diamond produced by Shanghai Zhengshi Technology Co. Ltd. (figure 1; GIA report number 2225246686) weighed 16.41 ct and measured 13.97 × 13.87 × 9.56 mm, with G color and VVS2 clarity. The strong graining distributed throughout it created a “wavy” appearance (view the video clip below). In addition, a few tiny pinpoints were present. Absorption spectroscopy in the infrared region revealed this was a typical type IIa diamond. Except for absorptions from the diamond itself, no other defect-related absorption was detected in this region. Photoluminescence spectroscopy collected at liquid nitrogen temperature with 514 nm laser excitation (figure 2, left) showed emissions from NV centers with zero-phonon lines (ZPL) at 575.0 nm and 637.0 nm with moderate intensities. Clear emissions from SiV– at 736.6 and 736.9 nm were detected. Weak emissions at 596 and 597 nm, which are specific to CVD diamond and also unstable at high temperature, were recorded overlapping with side bands of the NV0. Photoluminescence spectroscopy with 457 nm laser excitation (figure 2, right) detected weak emissions at 503.5 nm (3H) and 467.6 nm. Similar to the emission at 596 and 597 nm, the 467.6 nm center is CVD-specific and would be annealed out at very high temperature. No emission from the H3 defect was observed. All these spectroscopic features confirmed this was a CVD diamond with no post-growth treatment to improve the color.

Figure 2. Left: The photoluminescence spectrum with 514 nm laser excitation under liquid nitrogen temperature showed typical features of as-grown CVD diamond. Right: In the photoluminescence spectrum with 457 nm laser excitation under liquid nitrogen temperature, weak emissions from the 3H defect and from the 467.6 nm center were recorded.

	New Record Size for CVD Laboratory-Grown Diamond

Images collected under deep short-wave UV excitation showed strong orange-red fluorescence with banded blue regions (figure 3). The blue “columns” were nearly perpendicular to the table and extended almost continuously to the pavilion and culet. This feature was consistent with both the strong lattice dislocations observed under the microscope with crossed polarizers (figure 4) and its observable graining. Up to seven growth steps were revealed in the fluorescence and cathodoluminescence images (figure 5), with each layer of similar thickness. This princess-cut diamond had been faceted with its table face parallel to these layers for maximum weight retention, while keeping excellent proportions and symmetry.

Figure 3. Fluorescence imaging with deep short-wave UV excitation showed the typical orange-red fluorescence of as-grown CVD diamond with irregular blue “banding.” Up to seven growth layers were revealed. Image by Stephanie Persaud.

Figure 4. The large CVD diamond showed very strong dislocations under crossed polarizers, the main cause of its wavy appearance. Photo by Stephanie Persaud.

Figure 5. Cathodoluminescence imaging also revealed the seven growth steps. The dark dots in this image are related to the lattice dislocations. Image by Elina Myagkaya.
For CVD growth, this 16.41 ct diamond broke the record previously held by a 14.60 ct diamond (emerald cut, F color, VS2 clarity) produced in India, which surpassed the previous record of 12.75 ct (round brilliant, F color, VVS2 clarity), both reported last year (“IGI certifies world record 14.60 ct lab grown diamond,” IGI GemBlog, August 31, 2021). In comparison, the largest colorless or near-colorless HPHT laboratory-grown diamond is 15.32 ct (cushion cut, H color, I1 clarity), tested by GIA in 2018. The largest laboratory-grown diamond of any kind tested by GIA so far is a fancy-color 20.23 ct cushion cut (Fancy Vivid yellowish orange, VS2) produced using the HPHT method in 2019. GIA will continue to follow the development of laboratory-grown diamonds to ensure that all are properly identified. @chapter:9 @chapter:1 @chapter:9


# Publication Year: 2019
# Title: Tucson 2019 Overview
# Abstract: Buyers browse the selection of goods available at the 2019 AGTA GemFair in Tucson. Photo courtesy of AGTA.
The 2019 gem shows came to Tucson with a wealth of material, both new and old, as eager buyers descended on exhibitors to take in the latest trends. While traffic was not as heavy as in recent years, several vendors noticed an influx of young people looking for natural, untreated gemstones. Spectacular color in gems and stunning jewelry designs were on view, while many pointed to sustainable and ethical practices as a major consideration in their colored gemstone and jewelry purchases.

	Overview of gemstone supply and demand

The Asian market has slowed, according to Edward Boehm of RareSource (Chattanooga, Tennessee), and as a result, gems that have been popular in Asia, particularly China, are starting to gain traction in the United States. Boehm indicated that the growth of the Asian market is still driving production in African countries, particularly Nigeria, and Americans are the primary consumer of this increased production. Improving exchange rates have also worked in the American market’s favor. Dave Bindra (B&B Fine Gems, Los Angeles) said that while higher-end gemstones are still difficult to come by, they are as much in demand as ever. Commercial-grade gems, Bindra noted, have become more accessible. Like Boehm, he attributes this in large part to activity in the Chinese market in recent years. Shahin Aboosalih of SR Trading’s Hong Kong office talked to us about material that remains popular in the Chinese and Japanese markets.

Left: Opals like “The Chief,” a 14.41 ct Australian black specimen, were in demand this year. Photo by Kevin Schumacher, courtesy of 100% Natural Ltd. Center: Fancy-color sapphires, including this 50.08 ct color-change gem, were also popular. Photo by Robert Weldon/GIA, courtesy of Edward Boehm. Right: The secondary market is an excellent source for material, such as this 115.13 ct golden sapphire. Photo by Kevin Schumacher, courtesy of B&B Fine Gems.
Opal, particularly black opal, has seen a resurgence among high-end jewelers. Boehm believes there could be a growing appreciation for the gem due to the discovery of opal in Ethiopia, which has brought opal to different price points and different audiences in the past decade. Rod Griffin (Rod Griffin Boulder Opals) discussed his experiences in Australian opal mining and the new technology he is using to exploit deposits once thought to be depleted.
Color, of course, continues to reign, and dealers are seeing what Boehm called “an increased appreciation for the unusual.” Beyond the classic “Big Three,” vendors stocked gemstones such as sphene, grandidierite, and various colors of sapphire. Color-change stones seen in previous shows, such as pyrope garnet and alexandrites, were also on display and drawing new attention. Cutters, he noted, are making strides in recognizing and using to different effect specific phenomena in gemstones, such as the trichroism of tanzanite. Spinel remains the most popular “new” gem, according to Boehm, especially in nontraditional colors such as lavender and violet, which would have been cut too dark (or not at all) in the past. Gray spinel in particular made a splash at this year’s show, with several exhibitors stocking the material in a variety of cuts.
Brian Cook of Nature’s Geometry (Tucson) noticed a cross-pollination between the mineral and jewelry industries, with more designers and jewelers using raw euhedral stones to create unique looks. He also noted that several new mineral shows, developed out of dealers’ collectives rather than sponsored by one promoter, have come to the city and seem to be here to stay. The popularity of the Granada Gallery, which prides itself on its dedication to “fine natural design,” is one such indicator.
American gemstones were also in heavy rotation at the shows. Eric Braunwart of Columbia Gem House, who has long stocked American production in his inventory, said that sales of these products were good. Designer Derek Katzenbach discussed his use of American gemstones such as Maine tourmaline. And among the material seen was Montana sapphire, nephrite from Washington State, Oregon sunstone, and hyalite opals from Oregon.
Bindra noted that many of his company’s rare gems came out of the ground 20–30 years ago, and that he relies heavily on the secondary market to procure such material. In this way, he is able to provide his clients with the high-end material they have come to expect. This sentiment was echoed by Jared Holstein of Perpetuum Jewels, a wholesaler working with antique diamonds and colored stones in historical cuts for the bridal market. Holstein also finds the secondary market to be a good way to source gemstones in an ethical and environmentally sustainable fashion.
Responsibly sourced material continues to be heavily sought after. Braunwart said this might have been his most successful show in his 41 years at Tucson. He credits this in large part to his commitment to providing fair trade, responsibly sourced gemstones. Susi Smither, who founded The Rock Hound specifically to create an ethical jewelry line, delighted in showing us her Molten Muzo collection, which used responsibly sourced Colombian emeralds and recycled gold. And gem dealer and jewelry designer Roger Dery told us about Gem Legacy, the nonprofit he founded to benefit East African mining communities.
We hope you enjoy our coverage of the 2019 Tucson gem shows!
The following contributed to this report: Erin Hogarth, Tao Hsu, Jonathan Muyal, Lisa Neely, Aaron Palke, Duncan Pay, Albert Salvato, Kevin Schumacher, Jennifer Stone-Sundberg, Wim Vertriest, and Robert Weldon.

View Gallery

An Inside Look at the 2019 Tucson Shows @chapter:38 @chapter:3 @chapter:38


# Publication Year: 2013
# Title: Fish-Like Inclusion in Fancy Yellow
# Abstract: This pavilion view of the 4.76 × 4.30 × 2.75 mm Fancy yellow diamond displays the “fish” inclusion scene. The fish appears to be facing to the right. Magnified 40×. Photo by Martha Altobelli.

It is always a pleasant surprise to find a new and interesting inclusion during routine observation. But an inclusion that reminds us of a particular shape, an effect known as pareidolia (Winter 2007 Lab Notes, pp. 363–364), is a geologic wonder.
The New York laboratory recently received a natural yellow (graded as Fancy yellow) “Cape” 0.51 ct rectangular faceted diamond exhibiting such a feature. Examination of the stone revealed a series of table-reaching fractures and clouds that seemed to form the outline and scale-like detail of a fish (pictured at top). The inclusion is large in relation to the stone, encompassing nearly 75% of the table.
Nearly all fractures in diamond result from the interaction among multiple cleavage directions (The MicroWorld of Diamonds, Gemworld International, 2000, p. 97). While often detrimental to the value of a stone, this inclusion serves as a useful identifier, and such findings help keep the study of gems enjoyable. @chapter:41 @chapter:1 @chapter:41


# Publication Year: 2021
# Title: Dudley Blauwet (Dudley Blauwet Gems)
# Abstract: Figure 1. Unoiled Russian emeralds (a 1.29 ct emerald cut and a 1.14 ct pear shape) from Malyshevo, Ural Mountains, with intense bluish green color reminiscent of Paraíba tourmaline. Photo by Aria Agarwal; courtesy of Dudley Blauwet Gems.

              In February, colored stone dealer Dudley Blauwet attended the only 2021 Tucson “show,” held at Mineral City and the adjoining Sun Gems building. The Mineral City hub consists of several steel unit buildings that are classified as permanent business storefronts and therefore were not subject to the same COVID-19 requirements as events. In the 18 days Mr. Blauwet was there, he estimated that fewer than 500 people attended, including those associated with the 20–25 vendors. Beyond these vendors, another 6–10 gem- and mineral-related businesses that own warehouses in Tucson were open. Mr. Blauwet and one other vendor were the only ones carrying cut gems, while everyone else was offering minerals exclusively. A lack of fossils and meteorites was noticed.

Since summer, business has been fine for Dudley Blauwet Gems, as many of his online customers have been doing well and are looking to fill specific orders or rebuild stock. Using WhatsApp, he has been able to continue communicating with and purchasing material from suppliers such as a Sri Lankan family the business has worked with for nearly 40 years. This has included viewing sapphires from photos or videos almost daily. He has also been working with Russian contacts to purchase unoiled emeralds (figure 1), alexandrite, phenakite, and some demantoid. A source in Southeast Asia has also been supplying gray spinel.

Sales have been predominantly natural sapphire, unoiled emerald, gray spinel, and Vietnamese cobalt spinel. He noted that other stones such as aquamarine, green beryl, and morganite have been popular. The persistent demand for sapphire has been dominated by requests for teal, green to icy green, peach to apricot, “padparadscha,” periwinkle, purple-blue, and light to icy pink sapphire, as well as for traditional blue colors. Recently, he has received numerous calls for Mandarin garnet from Loliondo, Tanzania; heated blue zircon from Cambodia; and to a lesser extent Malaya garnet from Mahenge, Tanzania. Mr. Blauwet’s business mainly offers untreated natural sapphire, but they have had steady demand for heated blue rounds and matched pairs.

With the 2021 Pantone colors of the year being “Ultimate Gray” and “Illuminating” (a medium gray and butter yellow, respectively), Mr. Blauwet has seen a bit more interest in yellow sapphire over last year and steady interest in gray spinel (figure 2).

Figure 2. Yellow sapphire, gray spinel, and gray moonstone represent popular gems matching the 2021 Pantone colors of the year. Gray moonstone: 3.94 ct cabochon from India. Yellow sapphire: 2.39 ct oval from Dela, Sri Lanka, and 2.90 ct long cushion from Gilamale, Sri Lanka. Gray spinel: 0.93 ct cushion, 2.81 ct pear shape, and 1.16 ct round, all from Mogok, Myanmar. Photo by Aria Agarwal; courtesy of Dudley Blauwet Gems.
They have also developed a good market for unoiled Russian emerald, with some vendors regularly restocking.

Mr. Blauwet was able to provide some insight into the movement of material coming from mines around the world and the rough supply situation. With the political upheaval in Myanmar, Burmese gem production is expected to slow if not outright end for a while. Madagascar is opening up for travelers, but with a lack of express mail service, very little rough has left the island since last March. Some of the biggest gem mining operations in Sri Lanka are currently down. These combined supply slowdowns and stoppages have resulted in serious challenges—a very limited supply of rough worldwide and reduced movement of rough and gems to trading centers such as Bangkok or Hong Kong. As a result, the available supply of gems has been significantly dampened.

Mr. Blauwet mentioned that most of their trade shows for this year have been canceled, so they are handling increasingly larger orders and shipping 20 to 100 stones at a time to their manufacturing customers. Also, for the first time in Mr. Blauwet’s life, he has started a website to sell gems wholesale. His business is struggling to supply enough rough to its cutting factories to keep all of the cutters busy. Occasionally, they have been able to buy small rough to cut precision diamond melee in calibrated sizes, still a very popular product.

Finally, Mr. Blauwet shared with us some blue spodumene he has been storing in the vault. For decades he has been buying Afghan spodumene crystals, which have a strong blue color on the c-axis and a green color on the a- and b-axes. To avoid any exposure to daylight, these stones were wrapped in paper at the mines in Afghanistan. He has kept them in closed boxes to sell to customers specifically wanting spodumenes that have not been exposed to UV. As a test, he exposed several of them to Colorado sunlight in June and was able to literally watch them change to a full purple color down the c-axis and a pink color down the a- and b-axes within 40 minutes. Mr. Blauwet currently has several clean faceted stones in sizes up to approximately 300 carats (figure 3).

Figure 3. A 166.25 ct blue spodumene removed from storage. The stone is from Parun, a few kilometers from Paprok in Kamdesh District, Nuristan Province, Afghanistan. It was cut in Peshawar, Afghanistan, with the table perpendicular to the c-axis to achieve a blue color rather than green. Photo by Dudley Blauwet; courtesy of Dudley Blauwet Gems.
He has seen some dealers buy these crystals and take them to a show and watch in horror as they change over the course of three to five days from exposure to the various wavelengths of light present in the showroom—often the transition color before pink has strong unattractive gray tones. He reports that there are plenty of irradiated Afghan spodumenes on the market in Peshawar with a very strong emerald green color, including on the c-axis. The color is very unstable and with exposure to UV or daylight will change rather quickly, often turning an undesirable yellow-gray color. Mr. Blauwet described once making the mistake of buying a faceted example of these treated stones at a gem show in Peshawar from a dealer he did not know. When he unwrapped it years later, it had changed to an unattractive gray color with no exposure to UV or sunlight. @chapter:34 @chapter:2 @chapter:34


# Publication Year: 2013
# Title: Banded Mimetite
# Abstract: Figure 1. This mimetite cabochon, likely from Bolivia, weighs 177.75 ct and has an agate-like structure of yellow-brown and dark brown layers. Photo by Jaroslav Hyršl.

Mimetite is a member of the apatite group and a lead chloro-arsenate, known to collectors as one of the rarest faceted stones. Some yellow transparent specimens weighing up to 1 ct are known from old finds in Tsumeb, Namibia. Small orange translucent stones under 0.5 ct have been faceted from Chinese mimetite, and a new type of lapidary mimetite (figure 1), likely from Bolivia but purchased in Tucson without a reported locality, was identified recently.
The cabochon measured 40.5 × 31.7 × 7.2 mm and weighed 177.75 ct, with a very high luster. Its lapidary work was of low quality, but the stone had a very nice agate-like structure, with alternating yellow-brown and dark brown layers. It closely resembled two unusual ornamental stones: the colloidal variety of sphalerite (figure 2) known by the German name schalenblende, and the colloidal cassiterite variety called “wood tin.” Schalenblende is known from many localities worldwide, mainly Poland but also Bolivia, where it is very difficult to visually distinguish from mimetite. Wood tin is known to be from Bolivia and Mexico.

Figure 2. The sphalerite variety schalenblende has characteristics similar to those of banded mimetite. This specimen weighs 106.20 ct. Photo by Jaroslav Hyršl.
The RI of all three minerals is very high, over the refractometer limit. Loose stones can be easily distinguished by their hardness and specific gravity, and the hardness of mimetite and schalenblende is the same, about 3.5 on the Mohs scale. Wood tin is much harder, about 6.5. The SG of the mimetite was 6.31, considerably higher than the 3.8–4.2 of a typical schalenblende. The SG of wood tin can vary from 5.2 to 6.6, likely depending on the presence of thin chalcedony layers. Mimetite and wood tin are also inert in UV light, while schalenblende is usually yellow in long-wave UV. The mimetite was identified by powder X-ray diffraction by John Attard of San Diego, but its exact origin could not be determined. Thin veins of mimetite deposited from hot springs are known to have been mined from a deposit in Lomitas, located in La Paz Department, Bolivia. @chapter:12 @chapter:0 @chapter:12


# Publication Year: 2020
# Title: Zircon in Jadeite Jade
# Abstract: This doubly terminated tetragonal crystal in jadeite jade was identified as “high” zircon using Raman spectroscopy. Photomicrograph by Tyler Smith; field of view 2.90 mm.

One translucent green bangle bracelet recently examined by the author contained an interesting inclusion. The material was identified as dyed and polymer-impregnated jadeite jade using standard gemological testing and advanced spectroscopy, including UV-Vis, Raman, and infrared. This material would be classified as C-type jade in the trade.
Microscopic examination revealed a surprisingly well-formed transparent brownish crystal inclusion (see above). Raman analysis of the doubly terminated tetragonal prism revealed it to be “high” zircon (ZrSiO4). To confirm this, the full width at half maximum (FWHM) of the internal stretching mode at 1008 cm–1 was calculated as 6.05 cm–1, indicating a high level of crystallinity, as this band is known to broaden as metamictization occurs (L. Nasdala et al., “Metamictization and U-PB isotopic discordance in single zircons: A combined Raman microprobe and SHRIMP ion probe study,” Mineralogy and Petrology, Vol. 62, 1998, pp. 1–27).
Although interstitial zircon grains are not uncommon in jadeites, such a euhedral crystal is rarely observed and is especially unexpected considering the various treatments its host had undergone. @chapter:46 @chapter:4 @chapter:46


# Publication Year: 2017
# Title: Unusual Dark Orangy Red Cordierite
# Abstract: Figure 1. This 8.13 ct cordierite had an unusual dark orangy red color. Photo by Jian Xin (Jae) Liao.

The New York lab recently examined the transparent dark orangy red cordierite shown in figure 1. Cordierite, a magnesium aluminum cyclosilicate with the formula Mg2Al4Si5O18, is better known by its gemological name of iolite, which comes from the Greek ios (violet). The term is reserved for the violet through slightly violetish blue gem-quality variety of cordierite. Iolite’s typical colors have been compared to blue sapphires and tanzanites. These colors are thought to come from the charge transfer between Fe2+ and Fe3+ ions.

	The stone’s RI ranged from 1.515 to 1.547, with a birefringence of 0.037. This refractive index is much lower than what is listed in the literature for iolite, and we believe the discrepancy is due to the stone’s lower Fe content. Specific gravity was measured as 2.56. The stone showed strong trichroism ranging from orangy red to dark brown to purple. There was no fluorescence observed with exposure to long- and short-wave UV. Raman spectroscopy using 514 nm laser excitation conclusively identified the stone as cordierite (figure 2) with a strong match to the cordierite spectra in the RRUFF database (http://rruff.info).

	Figure 2. Raman spectroscopy identified the orangy red stone as a cordierite.

	Microscopic examination with fiber-optic illumination revealed fingerprints, rows of flaky whitish inclusions, and large fractures throughout the stone that had been filled with an unknown clarity-enhancing material (figure 3). The larger surface-reaching fractures in the stone appeared to have a “heat wave” appearance (figure 3B), that could be characteristic of the clarity-enhancing material. Cordierite, which is structurally similar to beryl, will easily develop fractures and is commonly clarity enhanced with oil-based fluids. Both cordierite and beryl are structurally similar in that they are cyclosilicates, containing linked six-member rings of tetrahedra that result in channels within the crystal structure. These channels are capable of trapping water along with cations such as from the alkali and alkaline earth metals. The high water content within the stone was represented by the strong overtone bands seen in the Fourier-transform infrared (FTIR) spectrum, with very similar features to that of hydrothermal natural beryl spectra. Laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) detected trace levels of alkali and alkaline metals.

	Figure 3. Various inclusions within the dark orangy red cordierite. Numerous partially enhanced fractures are visible (B), along with low visibility on the surface (D). Field of view 4.77 mm (A), 14.48 mm (B), 3.57 mm (C), and 3.57 mm (D). Photomicrographs by Augusto Castillo.

	A similar red cordierite, examined in December 2015, was said to be from the Iakora district of Fianarantsoa Province in southeast Madagascar (Spring 2016 GNI, pp. 97–98). The visible absorption spectrum we observed was similar to the one described by Fritsch et al. (figure 4). The spectrum had a decrease in absorption in the 400–500 nm region and low absorption between 600 and 800 nm, resulting in a transmittance window in the orange to red region that produced the color of the stone. These regions of low absorption are characteristic of the trichroic color components noted in the stone. We compared this visible spectrum to a GIA reference spectrum of ordinary iolite. The violet color of iolite is produced by a strong absorption band centered at approximately 580 nm, resulting from intervalence charge transfer to either valence state of Fe cations that might have occupied the divalent and trivalent sites in the crystal structure (substituting for Mg and Al, respectively; see M. O’Donoghue, Gemstones, Chapman and Hall Ltd., London, 1988, p. 77). Although the red cordierite contained a considerable amount of iron, this charge transfer did not appear to be taking place. The potential causes of the color are still unknown but can be linked to manganese (up to 486 ppmw in the orangy red sample and 248 ppmw in the violet sample) or iron, both of which were detected by LA-ICP-MS. This orangy red cordierite appeared to have roughly half as much iron as a saturated violet iolite (approximately 25,000 and 40,000 ppmw, respectively). No other transition metals varied significantly between the orangy red and violet samples. Regardless of the origin of color for the orangy red cordierite, naming this variety “iolite” could be misleading according to the definition of the term.

	This is the first time GIA has encountered a cordierite of this color.

	Figure 4. In these visible absorption spectra, notice the large window between 600 and 800 nm for the orangy red cordierite sample and the absorption band centered at 580 nm for the GIA reference spectrum of violet iolite. @chapter:15 @chapter:0 @chapter:15


# Publication Year: 2007
# Title: Fall 2007 Gem News International
# Abstract: Diamonds
            Large Diamond Mine to be Developed in Saskatchewan, Canada
            Spurious “Spiral Phantom” in Diamond
Colored Stones and Organic Materials
            Color-Zoned Axinite from Pakistan
            Multicolored Fluorite from Brazil
            Cr/V-Bearing Kyanite from Madagascar and Elsewhere
            Blue-Green Opal from Iran
            A Remarkably Large Fire Opal Carving
            An Unusually Translucent Non-Nacreous Pearl
            A New Gemstone from Italy: “Violan Quartz”
            New Sources of Marble-Hosted Rubies in South Asia
            Cr/V-Bearing Green Spodumene from Afghanistan
Synthetics and Simulants
            Large Beryl Triplets Imitating Colombian Emeralds
            Glass Imitation of Blue Spinel
Treatments
            Dyed Greenish Blue Chalcedony from Brazil
Conference Reports
            First European Gemmological Symposium: “Presence and Future of Gemmology”
            30th International Gemmological Conference
            “Diamonds in Kimberley” Symposium
            Diamond 2007
Announcements
            Visit Gems & Gemology in Tucson
            MJSA Vision Awards Competition
Exhibits
            Gemstone Treasures from Namibia
            Wine and Gems in Dijon
            Jewelry of Ben Nighthorse
            Exhibits at the GIA Museum
            Gems! Colors of Light and Stone at the Bowers Museum
            The Lester and Sue Smith Gem Vault

To view the full section, download the PDF above. @chapter:1 @chapter:0 @chapter:1


# Publication Year: 2005
# Title: Spring 2005 G&G Book Reviews
# Abstract: “Understanding Jewellery, 3rd Edition”
By David Bennett and Daniela Mascetti, 426 pp., illus., publ. by Antique Collector’s Club, Wood- bridge, England, 2003. US$89.50

“Collecting Fluorescent Minerals”
By Stuart Schneider, 192 pp., illus., publ. by Schiffer Publishing Ltd., Atglen, PA, 2004. US$29.95

“50-Year History of the Tucson Show”
By Bob Jones, 183 pp., illus., publ. by The Mineralogical Record, Tucson, AZ, 2004, US$20.00

“The Grandmasters of Mineral Photography”
136 pp., illus., publ. by Mineralogical Almanac, Moscow, 2004, US$45.00

“Tone Vigeland: Jewellery + Sculpture Movements in Silver”
By Cecilie Malm Brundtland, 182 pp., illus., publ. by Arnoldsche Art Publishers, Stuttgart, 2004 [in German and English], US$75.00

“The Tourmaline: A Monograph”
By Friedrich Benesch and Bernard Wöhrmann, 234 pp., illus., publ. by Verlag Urachhaus, Stuttgart, Germany, 2003, US$150.00

To view the full section, download the PDF above. @chapter:31 @chapter:2 @chapter:31


# Publication Year: -
# Title: The Royal Ruby
# Abstract: Ruby specimen gift of William F. Larson.  Cut rubies courtesy of Edward Boehm.

                      Ancient Indians called it “the king of precious stones.” Burmese warriors thought it made them invulnerable in battle. Medieval Europeans believed it cured hemorrhages and inflammatory diseases.

	The ruby has been prized since ancient times. And we still cherish it today.
	Rubies have remained popular for millennia because they are beautiful stones that evoke love, romance, and power. Here’s vivid proof of our fondness for them: rubies can still command the highest per-carat price of all colored stones.

		Nina Switzer-Spano, instructor of gemology at GIA, Carlsbad

Ruby belongs to a species of gemstones called corundum. The presence of the element chromium causes the naturally colorless corundum to turn red.

Myanmar’s Mogok Valley and Mong Hsu are important sources for high-quality rubies. Rubies are also mined in Madagascar, Cambodia, Sri Lanka, Vietnam, and other countries.

Color is one of the most important factors in determining a ruby’s value. Rubies range from an orangy red to a purplish red. Historically, the name “pigeon’s blood” has been used to describe vivid red rubies; however it is best to avoid using this trade term as it can be misinterpreted.

	Gift of Inta Gems.

Almost all rubies are heat-treated to improve their color. For example, rubies lose their brownish color; rubies mined in Sri Lanka become a more intense red when heat-treated; and rubies from Mong Hsu, Myanmar lose their dark color-zoned centers.

Rubies that are not treated command far higher prices than their enhanced counterparts. Assume a ruby is heat-treated unless an identification report says otherwise. Glass filling is another common and much less durable treatment.

Also be aware that synthetic rubies are popular in the marketplace. Manufactured since the late 1880s, synthetic rubies offer consumers a more affordable option than natural ones. Their place in the display case is perfectly legitimate. If a treatment or a country of origin is known, it must be disclosed. Disclosure is essential to building customer confidence and trust.

Tips on Rubies

		Rubies are rich in lore and romance. Be sure to share this with consumers.

		If all factors are equal, rubies mined in Burma are usually more desirable than rubies from other places. You may want to submit a ruby to GIA to identify if it’s natural or synthetic, or treated or untreated. Additional testing is available to determine country of origin. A GIA report with this information can let you purchase and/or sell these gems with confidence.

		Rubies are extremely hard and durable. Let customers know that they can wear them every day, but should make sure that the ruby does not rub against other gemstones, as they can damage softer ones like emerald and topaz.

To learn more about rubies, visit the GIA Gem Encyclopedia Ruby Page @chapter:40 @chapter:0 @chapter:40


# Publication Year: 2014
# Title: Unusual Short-Wave UV Reaction in Synthetic Blue Spinel
# Abstract: Figure 1. This 1.44 ct synthetic spinel was grown by the Verneuil process but displayed the short-wave UV reaction of a flux-grown sample. Photo by Pragati Verma.

ABSTRACT
The Indian Gemological Institute – Gem Testing Laboratory recently examined a 1.44 ct blue oval mixed cut specimen (figure 1). Standard gemological testing revealed the following properties: RI—1.728; hydrostatic SG—3.64; strong anomalous double refraction under the polariscope; Chelsea filter reaction—strong red; and red transmission in fiber-optic light. The sample showed general absorption bands between 535–550, 560–590, and 615–635 nm in the handheld spectroscope. Microscopic examination with a fiber-optic light source revealed shiny dotted inclusions that were scattered and created a wavy pattern; in some areas, the dotted inclusions were arranged in a series (figure 2). This wavy pattern has not been reported in natural spinel. The author has seen this pattern in some Verneuil synthetic spinel. There is a possibility that these inclusions might be very minute gas bubbles or unmelted feed powder.

Figure 2. Series of dotted inclusions were seen in some areas of the synthetic spinel. The dots were so concentrated that it was difficult to distinguish them individually. Photomicrograph by Pragati Verma; magnified 25×.
These properties—higher RI, higher SG, red Chelsea filter reaction, anomalous double refraction, and absorption spectrum features—are diagnostic features of cobalt-doped synthetic blue spinel grown by the Verneuil (flame-fusion) process (M. O’ Donoghue, Synthetic, Imitation & Treated Gemstones, Butterworth-Heinemann, Oxford, UK, 1997, p. 153).

When tested with UV, this synthetic spinel had an unusual reaction. Under both long- and short-wave UV, the sample showed red fluorescence (figure 3). This was an unexpected short-wave UV reaction for Verneuil-grown blue synthetic spinel, which generally shows a mottled blue to bluish white reaction. This kind of fluorescence was observed in synthetic blue spinel grown by a flux method (S. Muhlmeister et al., “Flux-grown synthetic red and blue spinels from Russia,” Summer 1993 G&G, pp. 81–98).

Figure 3. The synthetic spinel displayed red fluorescence under short-wave UV. Photo by Pragati Verma. @chapter:24 @chapter:0 @chapter:24


# Publication Year: 2014
# Title: Screening of Small Yellow Diamond Melee for Treatment and Synthetics
# Abstract: Figure 1. This group of 359 intensely colored round yellow diamonds (0.02–0.03 ct) was screened by GIA’s New York laboratory. Among these, the majority were natural (left), 14 were HPHT synthetics (middle), and one was HPHT-treated natural diamond (right). They all displayed uniform appearance and could not be distinguished visually. Photo by Sood Oil (Judy) Chia.

Diamond treatment and synthesis have undergone significant developments in the last decade. During this time, the trade has grown increasingly concerned about the mixing of treated and/or synthetic diamonds with natural melee-sized goods. Because it is often not feasible to test every small diamond in a parcel, many of these products could be traded without being tested individually by a gem lab. GIA’s New York laboratory recently tested two large groups of melee yellow diamonds submitted for screening of treatments and synthetics. The results will likely have profound implications for how melee diamonds are handled in the trade.

A parcel of 359 round diamonds between 0.02 and 0.03 ct was submitted for identification. They showed uniform appearance, intense yellow color, and good clarity. Based on spectroscopic analysis, each sample’s color was attributed to trace concentrations of isolated nitrogen. Gemological observations, infrared absorption spectroscopy, and DiamondView analysis confirmed that 344 of them were natural diamonds, 14 were grown by HPHT (high-pressure, high-temperature) synthesis, and one was an HPHT-treated natural diamond (figure 1).

Of the 14 synthetic diamonds, eight were dominated by A-aggregate form nitrogen with trace isolated nitrogen, while the other six showed negligible amounts. All had widespread pinpoint inclusions, a feature typical of HPHT synthetic diamonds. Characteristic growth features of HPHT synthesis were confirmed using a DiamondView fluorescence instrument on six of them. The synthetic diamonds with a high concentration of A-aggregate form nitrogen were produced at much higher temperatures, indicating more than one producer.

To gain perspective on the surprisingly high prevalence of synthetic and treated diamonds found in this parcel, we analyzed an additional parcel containing 525 samples, with similar results. One of these was HPHT-processed, while 10 displayed the spectral, microscopic, and fluorescence characteristics typical of HPHT synthetics; we concluded that the remaining 514 were natural and untreated. Typical DiamondView characteristics of HPHT synthetics were observed, but most of the HPHT synthetics showed fluorescence patterns similar to those of natural diamonds (figure 2). This observation emphasizes the importance of infrared absorption spectroscopy, in addition to DiamondView imaging, when determining diamond origin.

Figure 2. These DiamondView fluorescence images show (A) growth sector patterns typical of HPHT synthetic diamonds, (B) HPHT treatment, and (C and D) uncharacteristic HPHT synthetic patterns. Images by Martha Altobelli and Caitlin Dieck.
This study indicates that melee diamonds in the marketplace are being contaminated by synthetic and treated diamonds. Screening analysis by gem labs is essential to ensuring the correct identification. An efficient and reliable screening can be performed using infrared absorption spectroscopy, DiamondView fluorescence imagery, and optical microscopy. From our analysis of 883 melee samples in all, we concluded that 857 were natural diamond (97.1%), 24 were HPHT synthetic diamond (2.7%), and two were HPHT-processed natural diamonds (0.2%). @chapter:36 @chapter:1 @chapter:36


# Publication Year: 2015
# Title: Near-Colorless Melee-Sized HPHT Synthetic Diamonds Identified in GIA Laboratory
# Abstract: Figure 1. These six near-colorless round brilliant melee, ranging from 0.01 to 0.005 ct, proved to be HPHT synthetic diamonds. Photo by Nuttapol Kitdee.

              With significant development in diamond treatments and synthesis over the last decade, the trade has serious concerns about treated and/or synthetic material mixed with natural melee-sized stones. The mixing of treated and synthetic diamonds with yellow natural melees was previously reported (Winter 2014 Lab Notes, pp. 293–294; Spring 2015 Lab Notes, pp. 64–65). In order to ensure consumer confidence, it is essential to screen melees so as to distinguish all treated and synthetic goods.

Recently, the Bangkok lab had the opportunity to examine six melee-sized specimens submitted for synthetics and treatment screening. The transparent, near-colorless round brilliants ranged in size from 0.005 to 0.01 ct (figure 1). Microscopic observation revealed no obvious inclusions. Between crossed polarizing filters, very little or no strain was observed. Infrared absorption spectra showed that four of the samples were type IIa diamonds with no detectable defect-related absorption, while the other two were type IIb diamonds accompanied by uncompensated boron showing moderately strong absorption at approximately 2800 cm–1. Photoluminescence spectra obtained at liquid-nitrogen temperature with 514 and 633 nm laser excitations revealed an emission doublet of the negatively charged silicon split-vacancy defect [Si-V]– at 736.6/736.9 nm for five of the samples, while 830 nm laser excitation showed an emission doublet at 883.0/884.7 nm owing to a nickel-related defect for all six samples (figure 2). DiamondView imaging revealed either blue or green fluorescence, together with characteristic growth features of HPHT synthesis, as seen in figure 3. Strong blue phosphorescence was also observed for all six samples. These gemological and spectroscopic features confirmed that the specimens were grown by HPHT synthesis.

Figure 2. Photoluminescence spectra at liquid-nitrogen temperature of a small near-colorless HPHT synthetic diamond. The spectra displayed emission peaks at 736.6 and 736.9 nm related to a [Si-V]– defect (left, 514 nm laser excitation) and at 883.0 and 884.7 nm associated with a Ni-related defect (right, 830 nm laser excitation).

Figure 3. This DiamondView image of one sample (third from the left in figure 1) shows the characteristic growth features of HPHT-grown synthetic diamonds. DiamondView image by Charuwan Khowpong.
To the best of our knowledge, this is the first examination of near-colorless HPHT synthetics of these sizes by a gemological laboratory. Discovery of these HPHT synthetic diamond melee reaffirms the need to screen the huge volume of near-colorless melee currently in the trade. @chapter:9 @chapter:1 @chapter:9


# Publication Year: 2001
# Title: A New Method for Imitating Asterism
# Abstract: Several gems were recently examined that showed stars with an unnatural appearance or an unusual number of rays. Asterism in some of these gem materials is very rare, or has not been seen previously by the authors. Microscopic examination revealed that these “stars” were produced by using what appeared to be a rough polish to scratch lines in an oriented fashion onto the upper surface of the cabochons. @chapter:19 @chapter:0 @chapter:19


# Publication Year: 1981
# Title: Heat Treating Ruby and Sapphire: Technical Aspects
# Abstract: Ruby and sapphire of natural or synthetic origin can be heat treated to improve asterism; to remove asterism or silk; to improve, add, or remove color; and even to alter imperfections. At least nine distinct processes can be identified, although several may occur simultaneously. Some of these treatment methods correspond to natural processes and may not leave any evidence of their use; others do not correspond to natural processes and are readily identifiable. @chapter:19 @chapter:1 @chapter:19


# Publication Year: 2017
# Title: Natural Conch “Rosebud” Pearls
# Abstract: Figure 1. “Rosebud” conch pearls of various pink tones ranging from 0.93 to 14.72 ct. Photo by Sood Oil (Judy) Chia.

Non-nacreous conch pearls from Strombus gigas are known mainly for their very attractive pink color and distinctive shimmering appeal due to the characteristic flame structures on their surfaces. Although conch pearls are found in various tones of yellow, brown, and white, the most desirable hue is undoubtedly pink with an intense saturation. The flame structures are due to “crosswise arrays of bundles of aragonite laths or fibers that may reflect or absorb the light that falls on the structure, letting it appear bright or dull” (H.A. Hänni, “Explaining the flame structure of non-nacreous pearls,” The Australian Gemmologist, Vol. 24, No. 4, 2010, pp. 85–88).

In late 2016, GIA’s New York lab staff had the opportunity to study part of Susan Hendrickson’s conch pearl collection. Among the assortment of conch pearls of various sizes, colors, and shapes, a few “rosebud” specimens caught our attention (figure 1). The term “rosebud” is most commonly used to describe characteristically shaped freshwater nacreous pearls, but this is the first time GIA has examined conch pearls with such shapes (figure 2). The nine pink specimens had roundish outlines with a button-like appearance. But in keeping with the rosebud pearl form, they exhibited differences in the bumps or ridges on their surfaces. Some bumps were rounded and spread out, while others were jagged and tightly grouped. The authors could not locate any reports of rosebud conch pearls in the literature, and the cause of these distinctive surface structures is unknown. One possible explanation is that when a pearl forms in a pearl sac positioned in a region of muscular activity rather than the mantle, it will not form in a smooth symmetrical shape (E. Fritsch and E.B. Misiorowski, “The history and gemology of Queen conch ‘pearls’,” Winter 1987 G&G, pp. 208–221).

Figure 2. A shape comparison of a 4.90 ct American freshwater pearl exhibiting
rosebud form (A) and three conch pearls, weighing 1.30, 0.66, and 0.91 ct (B–D).
Photos by Tino Hammid (A) and Joyce WingYan Ho (B–D).
All nine samples displayed typical flame structures under magnification (figure 3). Some of them did not exhibit the flames on the bumpy surface, but only within the smoother areas. Microradiography revealed a tight internal structure with uneven outlines corresponding to the bumpy surfaces. The Raman spectra were characteristic of aragonite and clearly showed additional natural polyenic pigment peaks, both as expected for pearls formed in Strombus gigas mollusks.

Figure 3. This 6.21 ct rosebud conch pearl shows characteristic flame structure at the surface. Photos by Joyce WingYan Ho; fields of view 10.79 mm and 1.26 mm (inset).
There are records of attempts to cultivate conch pearls (H. Acosta-Salmón and M. Davis, “Inducing relaxation in the queen conch Strombus gigas (L.) for cultured pearl production,” Aquaculture, Vol. 262, No. 1, 2007, pp. 73–77; N. Sturman et al., “Cultured Queen conch pearls—A comparison to natural Queen conch pearls,” 32nd International Gemmological Conference, Interlaken, Switzerland, 2011; Summer 2015 GNI, pp. 201–202). No further news about the commercial production of cultured conch pearls has reached the market, however. As a result, conch pearls are still highly desirable and valued by the trade and specialty collectors. The opportunity to study such unique and exciting examples of rosebud conch pearls allowed GIA to expand its understanding of rosebud conch pearls for future reference. @chapter:11 @chapter:4 @chapter:11


# Publication Year: -
# Title: GIA's Gubelin Gem Project: Garnet
# Abstract: Photo by Robert Weldon/GIA

Often thought of as a deep red gemstone, garnet can also be yellow, orange, green or brown – any color except blue. There are six common garnet minerals – almandine, andradite, grossular, pyrope, spessartine and uvarovite – and several rare species. Gem varieties include green demantoid and tsavorite, orangy red hessonite and pink/red rhodolite. Besides brilliance and attractive colors, garnets sometimes exhibit optical phenomena such as asterism (a star-shaped pattern of reflections), chatoyancy (a “cat’s-eye” seen in reflected light), or a color change when viewed under different types of lighting.

33197

			18.34 ct Garnet (Almandine - Spessartine)
			Czech Republic (PDF)

33222

			12.86 ct Garnet (Almandine - Spessartine)
			India (PDF)

33308

			2.10 ct Garnet (Andradite)
			Korea (PDF)

33282

			16.02 ct Garnet (Andradite)
			South Africa (PDF)

35637

			1.67 ct Garnet (Andradite) - Demantoid
			Iran (PDF)

33307

			4.12 ct Garnet (Andradite) - Demantoid
			Italy (PDF)

33303

			4.24 ct Garnet (Andradite) - Demantoid
			Locality not stated (PDF)

33301

			4.31 ct Garnet (Andradite) - Demantoid
			Locality not stated (PDF)

33300

			5.22 ct Garnet (Andradite)  - Demantoid
			Locality not stated (PDF)

33223

			3.59 ct Garnet (Grossular)
			Mali (PDF)

33265

			6.57 ct Garnet (Grossular)
			Tanzania (PDF)

33242

			11.04 ct Garnet (Grossular)
			Tanzania (PDF)

34991

			14.54 ct Garnet (Grossular)
			Tanzania (PDF)

33239

			16.95 ct Garnet (Grossular)
			Tanzania (PDF)

33298

			10.99 ct Garnet (Grossular) - Hessonite
			Sri Lanka (PDF)

33299

			12.36 ct Garnet (Grossular) - Hessonite
			Sri Lanka (PDF)

33293

			14.18 ct Garnet (Grossular) - Hessonite
			Sri Lanka (PDF)

33292

			16.99 ct Garnet (Grossular) - Hessonite
			Sri Lanka (PDF)

33281

			23.86 ct Garnet (Grossular) - Hessonite
			Sri Lanka (PDF)

34842

			25.65 ct Garnet (Grossular) - Hessonite
			Sri Lanka (PDF)

35007

			6.96 ct Garnet (Grossular) - Hessonite
			Tanzania (PDF)

34358

			1.75 ct Garnet (Grossular) - Tsavorite
			Kenya (PDF)

35569

			3.65 ct Garnet (Grossular) - Tsavorite
			Tanzania (PDF)

33229

			3.87 ct Garnet (Pyrope)
			Tanzania (PDF)

33278

9.22 ct Garnet (Pyrope) Tanzania (PDF)

33313

			11.45 ct Garnet (Pyrope)
			Tanzania (PDF)

34395

			12.22 ct Garnet (Pyrope - Almandine)
			Madagascar (PDF)

34542

			10.24 ct Garnet (Pyrope - Almandine)
			Myanmar (PDF)

34841

			8.14 ct Garnet (Pyrope - Almandine)
			Sri Lanka (PDF)

34769

			19.12 ct Garnet (Pyrope - Almandine)
			Sri Lanka (PDF)

34759

			30.60 ct Garnet (Pyrope - Almandine)
			Sri Lanka (PDF)

33201

			11.42 ct Garnet (Pyrope - Almandine)
			Tanzania (PDF)

35213

			14.55 ct Garnet (Pyrope - Almandine)
			United States (PDF)

33459

			1.92 ct Garnet (Pyrope - Almandine) - Rhodolite
			Tanzania (PDF)

33461

			2.54 ct Garnet (Pyrope - Almandine) - Rhodolite
			Tanzania (PDF)

33206

			4.43 ct Garnet (Pyrope - Almandine) - Rhodolite
			Tanzania (PDF)

33199

			18.88 ct Garnet (Pyrope - Almandine) - Rhodolite
			Sri Lanka (PDF)

35021

			14.38 ct Garnet (Pyrope - Almandine) - Rhodolite
			Tanzania (PDF)

33198

			18.53 ct Garnet (Pyrope - Almandine) - Rhodolite
			Tanzania (PDF)

34387

			44.28 ct Garnet (Pyrope - Spessartine)
			Madagascar (PDF)

35068

			13.80 ct Garnet (Pyrope - Spessartine)
			Tanzania (PDF)

34338

			14.57 ct Garnet (Spessartine)
			Kenya (PDF)

34719

			7.42 ct Garnet (Spessartine)
			Namibia (PDF)

33251

			11.29 ct Garnet (Spessartine)
			Nigeria (PDF)

33249

			5.13 ct Garnet (Spessartine)
			Sri Lanka (PDF)

34844

			9.81 ct Garnet (Spessartine)
			Sri Lanka (PDF)

34899

			13.07 ct Garnet (Spessartine)
			Sri Lanka (PDF)

35227

			7.94 ct Garnet (Spessartine)
			United States (PDF) @chapter:3 @chapter:0 @chapter:3


# Publication Year: 2010
# Title: Yellow Scapolite from Ihosy, Madagascar
# Abstract: Attractive yellow to light greenish yellow gem scapolites have been mined from a skarn deposit near the town of Ihosy, in southern Madagascar, since the late 1990s. Chemical analysis indicates that the scapolites have a mostly meionite content, with lesser amounts of marialite and a small percentage of silvialite. These results are agreeable with the RI measurements and IR spectra. Inclusions were identified as diopside, garnet (andradite-grossular), and mica (probably phlogopite) consistent with the minerals accompanying scapolite in Ihosy skarns. The samples’ UV fluorescence appears to be distinctive from that of commercially available scapolites from other localities. @chapter:12 @chapter:0 @chapter:12


# Publication Year: -
# Title: Building the Color Treated Diamond Market
# Abstract: VIdeo on Hold for edit

Interview with Rahul Karnavat, Lotus Colors, Inc.

Mr. Karnavat lives in a colorful world, and he shares it with us in these interviews from the 2013 Tucson Gem Show. Presenting a dazzling array of diamonds in a rainbow of enhanced colors, Mr. Karnavat explains his color-enhancing processes one by one.

Sensing the need for colored diamonds in a world with a growing shortage of naturally colored ones, Mr. Karnavat’s company, Lotus Colors, Inc., began irradiating diamonds in the early 1990s. Gradually, they added heat and high-pressure high-temperature (HPHT) treatments and, most recently, a modern coating process.

Mr. Karnavat describes the coatings—actually extremely thin films—at length. He explains that they can result in many lovely colors, but they’re fragile, requiring care in setting, jewelry repair, and other procedures. An advantage of their fragility is that if a color goes out of style, Lotus can just give the color-coated diamonds an acid bath and recoat them in a new, more popular color.

Mr. Karnavat emphasizes the importance of disclosure for all treatments, especially coatings. In his words, “We scare people before we sell it.”

Mr. Karnavat’s company also has a line of jewelry set with their color-enhanced diamonds. It’s only 5-10% of their business, but it helps with sales of the loose stones by showing them set in jewelry. As he shows some examples, he explains how they carefully coordinate the colors of the metal with the enhanced diamond colors.

Mr. Karnavat tells us that public acceptance of colored diamonds has increased greatly since the early days, along with acceptance of technology in general. Treatments are the future, he says: Naturally colored diamonds aren’t getting any less expensive. Even more important, the supply is not there—especially of natural pinks—even if the customer has the money. @chapter:41 @chapter:1 @chapter:41


# Publication Year: 1989
# Title: Spring 1989 G&G Lab Notes
# Abstract: Transparent Green Augite
Covellite
Coated Diamonds Again Seen in the Trade
Unusual Inclusions in Diamond
American Freshwater Natural Pearls
Cultured Black Pearl Mystery
A Large Phosphophyllite Crystal
Verneuil Synthetic Ruby with Needle-Like Inclusions
A Large Fine-Color Star Sapphire
An Unusual Green Star Sapphire
Pink Spinel from the USSR
Synthetics and other "Modern" Substitutions in Period Jewelry and Reproductions

To view the full section, download the PDF above. @chapter:16 @chapter:1 @chapter:16


# Publication Year: 2002
# Title: Portable Instruments and Tips on Practical Gemology in the Field
# Abstract: Buying gems or jewelry can be challenging even when one has access to a fully equipped lab. However, most purchases are actually made in environments that make it difficult to carry anything more than a loupe, a flashlight, and a pair of tweezers. Practice with these and the additional portable gem instruments described in this article will enable the buyer to develop the keen senses needed to better ascertain the identity and quality of the material being considered. Practical tips that may be applied in the field are also included in each section. Common sense must dictate how a clue is applied, and some tests will merely help narrow down the possibilities. @chapter:23 @chapter:0 @chapter:23


# Publication Year: -
# Title: Treated Fancy Red Diamond
# Abstract: Examines a 2.14 ct oval-cut diamond, graded as Fancy red, whose red color was produced through a combination of high-presssure, high-temperature (HPHT) treatment and irradiation plus annealing. Download PDF to view. @chapter:36 @chapter:1 @chapter:36


# Publication Year: 1990
# Title: Summer 1990 G&G Book Reviews
# Abstract: “Encyclopedia of Minerals, 2nd Edition, December 1989”
By Willard L. Roberts, Thomas J. Campbell, and George R. Rapp, Jr., 979 pp., illus., publ. by Van Nostrand Reinhold, New York, 1989. US$99.95

“Black Pearls of Tahiti”
By Dr. Jean-Paul Lintilhac, photographs by Alain Durand, 116 pp., illus., publ., by Royal Tahitian Pearl Book, Papeete, Tahiti, 1987. US$39.95

“Gem Identification Made Easy: A Hands-On Guide to More Confident Buying and Selling”
By Antoinette L. Matlins and A. C. Bonanno, 270 pp., illus., publ. by Gemstone Press, South Woodstock, VT, 1989. US$29.95

To view the full section, download the PDF above. @chapter:30 @chapter:0 @chapter:30


# Publication Year: 1991
# Title: Curves and Optics in Nontraditional Gemstone Cutting
# Abstract: A series of cuts, designed by the author, exhibit extraordinary optical effects that result from a combination of curved surfaces and plane facets placed to take advantage of internal reflection. Examples are provided that illustrate the cutting techniques for two of these "open-table" cuts. @chapter:34 @chapter:3 @chapter:34