Title: Black Non-Nacreous Pearl Imitations Made of Beads Cut from Shell Abstract: Figure 1. Two near-round beads cut from shell, 9.22 × 9.15 × 8.67 mm (left, 5.04 ct) and 9.51 × 9.44 × 8.69 mm (right, 5.45 ct). Photo by Hasan Abdulla.

DANAT (Bahrain Institute for Pearls & Gemstones) recently received a 5.04 ct bead (9.22 × 9.15 × 8.67 mm) and a 5.45 ct bead (9.51 × 9.44 × 8.69 mm), both of near-round shape (figure 1). Under the microscope, both beads presented columnar structures in some areas, similar to those observed in some non-nacreous pearls (N. Sturman et al., “Observations on pearls reportedly from the Pinnidae family (pen pearls),” Fall 2014 G&G, pp. 202–215), as well as elongated structures due to fibers reaching the surface (figure 2). Raman spectra with a 514 nm green laser were difficult to acquire, as they revealed high luminescence possibly linked to their high organic matter content; however, there was enough Raman signal to be able to identify calcite and aragonite. The calcium carbonate identification was confirmed by acquiring FTIR reflectance spectra. In the Raman spectra, weak bands linked to polyenic pigments were also observed.

Figure 2. Columnar structures observed in the smaller bead made of calcite (left, reflected light) and elongated structures made of aragonite (center, reflected light) due to fibrous crystals of aragonite (right, reflected and transmitted light). Similar structures were also observed on the larger bead. Polish lines are observed in all images. Photomicrographs by Hasan Abdulla; fields of view 1.5 (left), 1.1 (center), and 2.4 mm (right).
Chemical analysis of the beads using energy-dispersive X-ray fluorescence (EDXRF) did not show any measurable manganese. Strontium was above 800 ppmw, and they remained inert under X-ray imaging, similar to saltwater pearls. Digital X-ray microradiographs and micro-CT did not show any internal structures.

Figure 3. Reaction of the beads under long-wave UV (top) and short-wave UV (bottom). Note the luminescence distribution in the different zones. Photos by Hasan Abdulla.

Figure 4. Under transmitted fiber-optic illumination, the 5.04 ct bead displayed a banded structure reminiscent of beads cut from the inner part of a shell. Photo by Hasan Abdulla.
Under long-wave and short-wave ultraviolet light, zoned/banded/layered fluorescence was observed (figure 3). Using transmitted fiber-optic illumination, banded structures and fibrous structures were visible with the unaided eye (figure 4). These characteristics were similar to those observed in imitation pearls made of non-nacreous shell material. Most of the imitation pearls described previously had a light color or were artificially dyed. The beads examined in this study, though, presented no evidence of any color treatment under the microscope or using EDXRF and Raman spectroscopy. The “zoned” fluorescence reaction under UV light was linked with different structures and not with the artificial colorants.
Large white beads with fibrous aragonite supposedly cut from bivalves from Tridacna species, which contain thick inner layers, have previously been used to imitate pearls (Summer 2004 GNI, p. 178; Summer 2006 Lab Notes, pp. 166–167; M. Krzemnicki and L. Cartier, “Fake pearls made from Tridacna gigas shells,” Journal of Gemmology, Vol. 35, No. 5, 2017, pp. 434–429). These beads were sometimes dyed to alter their coloration. A salmon-colored bead of about 10 mm, supposedly cut from the inner part of Lobatus gigas, was used to imitate coral (E. Disner and F. Notari, “Gastropod shell beads disguised in a coral necklace,” Journal of Gemmology, Vol. 34, No. 7, 2015, pp. 572–574). The beads we examined were of natural black color, and we are still looking for a mollusk that might have a non-nacreous inner shell layer where beads of that size could be cut.

Acknowledgments: The authors would like to extend their appreciation to Mr. Saud Bin Rajab (Manama, Bahrain) for allowing us to publish the study on these beads. Source: GIA @topic:5


Title: A Non-Nacreous Pearl Reportedly from Telescopium telescopium Abstract: Figure 1. The 1.72 ct yellowish brown and black non-nacreous (porcelaneous) pearl with Telescopium telescopium shells provided by the client. The intact shell is approximately 70 × 35 mm and the sawn shell is approximately 84 × 41 mm. Inset: An enlarged image of the pearl. Photos by Lhapsin Nillapat and Nuttapol Kitdee.
GIA’s Bangkok laboratory recently examined a yellowish brown and black non-nacreous button-shape pearl weighing 1.72 ct and measuring 6.64 × 6.53 × 5.07 mm. The pearl exhibited an attractive porcelain-like luster.
The client informed GIA that the pearl was found in a Telescopium telescopium shell. This edible snail (N. George et al., “DNA barcoding of gastropod Telescopium telescopium (Linnaeus, 1758) found at the Karachi coast, Pakistan,” Journal of Animal and Plant Sciences, Vol. 31, No. 5, 2021, pp. 1530–1536) was retrieved from an abandoned shrimp pond near a mangrove forest in Krabi, Thailand. The story of the pearl’s discovery was widely publicized in the local media. Though the client was unable to submit the shell from which the pearl was extracted, they provided us with samples of the same type of shell for further study (figure 1).

Figure 2. A: Obvious long cracks traversing the pearl’s darker side; field of view 7.20 mm. B: Intersecting flame structure on the pearl; field of view 2.40 mm. C: Intersecting flame structure on a cross section of the shell; field of view 4.80 mm. D: Banding and flame structure on a cut area of shell; field of view 4.80 mm. Photos by Ravenya Atchalak and Kwanreun Lawanwong.
Observation through a 10× loupe and a microscope revealed long cracks traversing the darker side of the pearl (figure 2A). No polishing lines or evidence of surface or color modification were observed, indicating that the shape and color were natural. The pearl and shells exhibited flame structures similar to those routinely observed in pearls such as those from the horse conch (Summer 2018 Lab Notes, pp. 211–212). Intersecting and overlapping flame structures typically observed in pearls from the Cassis genus (Fall 2012 Lab Notes, pp. 211–212) were also detected on the pearl (figure 2B) and shells (figure 2C). However, the banded structure observed on the cut shells (figure 2D) was not visible on the pearl, additional evidence that the client’s item was a pearl and not an imitation fashioned from shell.

Figure 3. Real-time microradiography revealed growth arcs close to the center and surface-reaching cracks (red arrow). Image by Ravenya Atchalak.

Figure 4. Raman spectra of the pearl and a shell obtained using a 514 nm argon ion laser revealed peaks related to the vibration modes of aragonite at 703, 1085, and 1464 cm–1 (obscured by stacking); polyenic-related peaks at 1015, 1120, 1296, and 1493 cm–1; and an additional peak at 1175 cm–1 that is also likely related to polyene. Spectra are offset vertically for clarity.
Real-time microradiography confirmed a natural whole pearl, as growth arcs close to the center and surface-reaching cracks were revealed (figure 3). As expected, energy-dispersive X-ray fluorescence analysis detected calcium as a major component in the pearl and shells, while manganese levels of less than 15 ppm and strontium levels ranging from 1005 to 2675 ppm verified a saltwater formation environment. The pearl’s natural color was substantiated using additional advanced spectroscopic methods. Raman spectra collected using a 514 nm argon ion laser on the pearl and shells (figure 4) revealed peaks related to the vibration modes of aragonite at 703, 1085, and 1464 cm–1; polyenic-related peaks at 1017, 1105–1120, 1297, and 1490–1500 cm–1 (S. Karampelas et al., “Polyacetylenic pigments found in pearls and corals,” 30th International Gemmological Conference, Moscow, 2007; L. Bergamonti et al., “The nature of the pigments in corals and pearls: A contribution from Raman spectroscopy,” Spectroscopy Letters, Vol. 44, No. 7-8, 2011, pp. 453–458); and an additional peak at 1175 cm–1 that is also likely related to polyene.
Surface observations and data collected from the pearl and shells using analytical methods appeared to support the claim that the pearl formed in this mollusk species. However, this can only be confirmed by conducting DNA barcoding analysis, which is a destructive test. This report adds to the growing list of natural pearls found in edible oysters and snails described in the literature (e.g., Winter 1995 Gem News, pp. 280–281; K. Scarratt et al., “A note on a pearl attached to the interior of Crassostrea virginica (Gmelin, 1791) (an edible oyster, common names, American or Eastern oyster),” Journal of Gemmology, Vol. 30, No. 1-2, 2006, pp. 43–50; Fall 2019 Gem News International, pp. 439–440; Fall 2020 Lab Notes, pp. 420–422; Summer 2021 Lab Notes, pp. 152–153). However, this is the first time a natural pearl has reportedly been discovered in a Telescopium species. Its unique appearance and characteristics provided a rare opportunity for GIA gemologists to examine and record data from a natural pearl originating from this marine snail. Source: GIA @topic:5


Title: A Near-Round Natural Pearl Discovered in the Edible Oyster Magallana bilineata Abstract: The inner and outer shell of M. bilineata (left and center). A near-round pearl (right) was found inside the shell. Photos by Sadar Aslam.
Pakistan, which has a coastline stretching 1,046 km (650 miles) along the Arabian Sea, the Indian Ocean, and the Gulf of Oman, is blessed with numerous marine resources, including oysters that mainly inhabit estuaries and mangrove habitats. In Sindh Province, some oyster reefs at Hab River Delta have high ecological and economic value. Nine edible oyster species belonging to the genera Crassostrea, Saccostrea, and Ostrea have been recognized from different localities there. Pearl-forming mollusks belonging to the genera Pinctada have been reported from Daran Beach.
The Ostreidae family includes edible oysters and is most commonly known as a source of seafood (K. Scarratt et al., “A note on a pearl attached to the interior of Crassostrea virginica [Gmelin, 1791] (an edible oyster, common names, American or Eastern oyster),” Journal of Gemmology, Vol. 30, No. 1-2, 2006, pp. 43–50). Of these, Magallana bilineata has the widest distribution in the Indo-Pacific region, encompassing the coasts of northern Arabia, the Bay of Bengal, the Andaman Sea, the Java Sea, South China and Vietnam, the Philippines, and Okinawa.
Magallana bilineata is a euryhaline species that inhabits backwaters, creeks, estuary banks, coastal bays, and lagoons, forming oyster beds on a large scale. A large number of specimens of this species from Hab River Delta were examined to study the taxonomic characteristics of the genus Magallana as part of a joint project between Japan and Pakistan. Ten shells of each species were opened. Only one shell of M. bilineata (150 mm shell height) contained a pearl, attached to tissues near the adductor muscle. It was near-round, with a smooth surface and a purplish and off-white color very similar to the inner shell layer of M. bilineata  (see above, left). The crystal structure of calcium carbonate was observed under high magnification. The non-nacreous, shiny pearl (see above, right) was 4.15 mm in diameter and weighed 0.02 g. The specimen is housed at the Centre of Excellence in Marine Biology, University of Karachi (part of the study collection of author SA).
Oysters living in tropical and warm regions have darker, more vivid, and more extensive coloration than those in cooler climates. Our finding is very similar to that of Scarratt et al. (2006), which found a pearl inside Crassostrea virginica that was attached to an adductor scar. In our case, the pearl was attached to the tissues near an adductor scar. This finding demonstrates the very rare phenomenon of edible oysters producing natural pearls. However, further work will be needed to determine its chemical composition using highly accurate analytical methods. Source: GIA @topic:5


Title: RFID Device Embedded in South Sea Bead Cultured Pearl Necklaces Abstract: Figure 1. A: Necklace of South Sea bead cultured pearls, 14.80–15.90 mm in diameter. Photo by Nuttapol Kitdee. B and C: Real-time microradiography (RTX) revealed one bead cultured pearl in the necklace containing an RFID device showing an obvious demarcation of typical shell bead nuclei. The embedded electronic component is visible as a white opaque stepped square feature. D: When aligned at right angles to the previous direction, the electronic component is harder to see but can be observed within a long, sharp laminated plane separating the two parts of the shell bead nucleus.
New technologies are increasingly being applied to cultured pearls, and it is exciting to witness developments in pearl traceability. GIA’s Bangkok laboratory recently received two South Sea bead cultured pearl necklaces, each consisting of 29 pearls ranging from 14.80 to 15.90 mm in diameter (strand A, figure 1A) and 14.40 × 14.20 mm to 16.20 mm in diameter (strand B, figure 2A). General observation under a binocular microscope revealed clear aragonite platelets characteristic of nacreous pearls, with no indications of treatment.

Figure 2. A: Necklace of South Sea bead cultured pearls, 14.40 × 14.20 mm to 16.20 mm in diameter. Photo by Nuttapol Kitdee. B–D: RTX analysis revealed five bead cultured pearls containing an off-center RFID device within the shell bead nucleus.
Real-time microradiography (RTX) revealed obvious demarcation features separating the shell bead nucleus from the overlying nacre layers. The nacre thickness range was consistent with bead cultured pearls produced by the Pinctada maxima mollusk (N. Sturman et al., “Bead cultured and non-bead cultured pearls from Lombok, Indonesia,” Fall 2016 G&G, pp. 288–297). However, the most striking feature was the presence of some electronic components within a few of the pearls. They were visible as opaque white squares with a stepped pattern in keeping with previously examined samples containing radio-frequency identification (RFID) devices (H.A. Hänni and L.E. Cartier, “Tracing cultured pearls from farm to consumer: A review of potential methods and solutions,” Journal of Gemmology, Vol. 33, No. 7-8, 2013, pp. 239–246; Spring 2020 Lab Notes, pp. 134–136). Interestingly, only a single pearl in strand A (figure 1, B–D) and five pearls in strand B (figure 2, B–D) contained an RFID device. The device is usually positioned off the center of the bead to avoid being drilled.

Figure 3. A: Necklace of South Sea bead cultured pearls, 10.04–12.21 mm in diameter. Photo by Tony Leung. B: RTX analysis of one of the pearls in the necklace revealed an RFID device. C: The internal structure was compared with two known bead cultured pearls containing RFID devices from GIA Hong Kong’s reference collection, and they proved to be identical. D: RTX clearly showed the outline of the square RFID device, as well as the sawn plane and small recess where the RFID device had been placed.
GIA’s Hong Kong lab has also begun seeing similar features in recent submissions (figure 3, A–B). The team compared the RTX data with some known bead cultured pearls containing an RFID device (figure 3, C–D) and confirmed that they were identical. The previous studies mentioned earlier describing RFID devices in bead cultured pearls have shown that these nuclei are produced by a patented pearl technology invented by Fukui Shell Nucleus Factory, which also supplies laminated beads to certain pearl farms. This explains the link between the laminating technique and its application in the production of RFID shell beads.
The use of RFID shell beads is known to assist in the storage of certain data such as a pearl farm’s location, mollusk data, and harvest date. However, a specific RFID reader is required to retrieve the data, so we were unable to obtain the information stored within these particular devices. Since the RFID devices do not influence their external appearance, the pearls containing a shell bead nucleus with such components are still identified as bead cultured pearls. Because the RFID device could increase the weight and have a misleading effect if undetected, a special comment is routinely included on GIA pearl identification reports as a means of disclosure. While pearl tracing technology has not been extensively adopted by the cultured pearl industry, the increasing number of electronic devices in shell bead nuclei submitted to the laboratory is noteworthy. GIA will continue to monitor and provide updates to the pearl trade and consumers. Source: GIA @topic:5


Title: A Reported Cassis Pearl from Key West, Florida Abstract: Figure 1. This oval pinkish orange porcelaneous pearl weighing 29.78 ct and measuring 17.86 × 15.64 × 14.58 mm was reportedly found in a queen helmet conch (Cassis madagascariensis), shown on the left with various Cassis species shells. Photo by Robert Weldon. Shells courtesy of Robin Willis.

Figure 2. Left: This porcelaneous pearl exhibited a fine, well-formed flame structure covering the entire surface, and a homogeneously spotted pattern was visible with the unaided eye. Photo by Robert Weldon. Right: Under magnification with fiber-optic illumination, the wide and spiky flame structure was evident. Photo Artitaya Homkrajae; field of view 2.90 mm.
The Carlsbad laboratory recently examined an oval non-nacreous pearl weighing 29.78 ct and measuring 17.86 × 15.64 × 14.58 mm (figure 1). The pearl possessed a uniform pinkish orange bodycolor and a porcelaneous surface with flame structures. The flames were short and wide and tapered to a point. This fine, well-formed flame structure looked like a homogeneous spotted pattern throughout the pearl’s surface (figure 2, left), yet the flame forms were evident at high magnification under the microscope (figure 2, right). Subsequently, Raman spectroscopic analysis with a 514 nm argon-ion laser verified the pearl was composed of aragonite, with peaks at 154, 181, 192, 207, 704, and 1085 cm–1 (J. Urmos et al., “Characterization of some biogenic carbonates with Raman spectroscopy,” American Mineralogist, Vol. 76, 1991, pp. 641–646); two strong polyene peaks at 1131 and 1523 cm–1 were indicative of natural color (C. Hedegaard et al., “Molluscan shell pigments: An in situ resonance Raman study,” Journal of Molluscan Studies, Vol. 72, No. 2, 2006, pp. 157–162). Real-time microradiography (RTX) revealed a dark gray oval void-like feature in the center and a growth ring in the outer area of the pearl (figure 3). Such a void can be found in natural pearls from a number of porcelaneous pearl-producing mollusks.

Figure 3. RTX imaging revealed the growth structure of the pearl: an ovalish void-like feature of less radiopacity in the center and a growth ring in the outer area. Image by Amiroh Steen.

Figure 4. This photo shows the pearl and the queen helmet shell in which it was found. Photo courtesy of the Bert Matcovich family.
Orange porcelaneous pearls are produced from various marine gastropod species such as queen conch (Lobatus gigas), Melo species, Cassis species, and horse conch (Fasciolariinae subfamily). The flame characteristics and pinkish orange bodycolor of this pearl were unlike those of orange porcelaneous pearls previously submitted to GIA. The client who submitted the pearl stated that it was found inside a queen helmet conch in the early 1960s by Bert Matcovich (figure 4), who owned a shell shop in Key West, Florida. Born into a family of shellers with more than 60 years of experience, Matcovich fished the waters off Key West for conchs and visited local shrimp boats daily in the 1960s to purchase various types of shells. This pearl was a remarkable discovery.
Queen helmet, also known as emperor helmet, is the common name for a marine gastropod species called Cassis madagascariensis, which belongs to the Cassidae family. The species is generally distributed in the tropical western Atlantic, including the Caribbean Sea (J.H. Leal, “Gastropods,” in K.E. Carpenter, The Living Marine Resources of the Western Central Atlantic, Vol. 1, Rome: Food and agriculture organization of the United Nations, 2002, pp. 99–127). Queen helmet shells have large, thick whorls with short spires, and three rows of knobs often appear on the body. They have a flat large parietal shield next to an aperture, and the color ranges from pale cream to deep salmon, often with a dark orangy brown color between the “teeth” (see again figure 4). Owing to their significant thickness, these colorful shells are widely used for cameo carving.
Cassis pearls typically have a fine and slender flame structure, often with intersecting flames. Their colors traditionally range from light orange to orangy brown, sometimes with patchy color. This pearl was unlike typical Cassis pearls examined by GIA, and its mollusk identity could not be confirmed with gemological testing. Nonetheless, this fine large natural non-nacreous pearl and its discovery story from six decades ago are noteworthy. Source: GIA @topic:5


Title: Old Techniques Reimagined: Maki-e Pearls Abstract: Figure 1. An inrō dating back to eighteenth-century Japan with gold maki-e and mother-of-pearl inlay. Courtesy of Getty Images.
At the AGTA show, Eliko Pearl (New York) exhibited a series of unusual cultured pearls, many of which were worked after culturing to create unique pieces of art. Among these, maki-e pearls caught the authors’ attention.
Maki-e is an ancient Japanese lacquer technique that translates to “sprinkled picture” and is said to have originated more than 1,200 years ago. A fine brush is used to paint a design with lacquer, which is then sprinkled with gold powder before the lacquer dries. More lacquer may then be painted again over the design and polished. For centuries, the meticulous technique has been used to decorate screens, inrō (a type of small case worn in traditional Japanese culture; figure 1), Japanese letter boxes, and other vessels, and it has now been adapted for use on pearls.
A representative from Eliko Pearl explained that each pearl is decorated by hand using a combination of urushi lacquer and 24K gold powder overlay, with abalone shell inlay (figure 2). The natural lacquer is derived from the sap of the urushi tree, which is native to Japan, China, Vietnam, and Southeast Asia. Sap can be harvested from a single tree for 14 to 15 years, during which the tree only yields about 200 grams of material. The sap also goes through a lengthy treatment process before it can be used as a lacquer. After application, the urushi lacquer must cure in a high-humidity environment (70–90%) in a series of thin layers. The time-consuming and laborious process of harvesting, processing, and applying the lacquer on pearls makes urushi lacquer a costly material, but the finished maki-e pearl is a treasured piece of art.

Figure 2. A pair of Tahitian pearls decorated with 24K gold maki-e and abalone shell inlay (left). A single near-round Tahitian pearl, decorated by the same technique in a flower motif (right). Photos by Emily Lane; courtesy of Eliko Pearl.
The décor adorns Tahitian pearls predominantly and can be found on matching pairs as well as single pieces. Prices vary from piece to piece based on the detail of the design and the size and shape of the pearl, with the most expensive shape being round (figure 3).

Figure 3. Trays of Tahitian maki-e pearls offered by Eliko Pearl at the 2022 AGTA show in Tucson. Available in a range of sizes in matching pairs and single pieces. Photo by Lisa Kennedy; courtesy of Eliko Pearl. Source: GIA @topic:5


Title: A Near-Field-Communication (NFC) Technology Device Embedded in Bead Cultured Pearls Abstract: Figure 1. An intact 7.83 ct Pinctada margaritifera bead cultured pearl (right), together with a sectioned sample (2.56 ct left and 4.46 ct center), embedded with a near-field-communication (NFC) chip. Photo by Diego Sanchez.
The Carlsbad laboratory received for examination two dark-colored bead cultured pearls embedded with an electronic device (figure 1) from Jeremy Shepherd, CEO of Pearl Paradise. The first sample had been cut in half by Mr. Shepherd in order to investigate the interior components; the smaller half weighed 2.56 ct and measured 10.63 × 9.73 × 3.88 mm (figure 1, left), and the larger half weighed 4.46 ct and measured 10.84 × 10.20 × 5.48 mm (figure 1, center). The second sample (figure 1, right) was intact and weighed 7.83 ct, measuring 10.84 × 10.20 × 5.48 mm. Both samples exhibited the typical external appearance of bead cultured pearls produced by the Pinctada margaritifera mollusk (referred to in the trade as “Tahitian” or “Black South Sea”). UV-Vis spectra of these samples showed the characteristic reflectance features typical of naturally colored pearls originating from this mollusk, with identifying features recorded at 405, 495, and 700 nm.
The cross-section surfaces of the two halves showed a straightforward bead cultured pearl structure. A round translucent white shell bead nucleus was clearly visible in the center. Its freshwater origin was subsequently verified with optical X-ray fluorescence imaging and EDXRF analysis. The alternating cream and brown concentric layers immediately overgrowing the bead were a combination of calcium carbonate and organic-rich materials (i.e., conchiolin) that are sometimes produced during the initial growth stage prior to nacre (aragonite) deposition. The subsequently deposited layers are dark-colored nacre commonly produced by the P. margaritifera mollusk. An electronic device was very obvious within a large partial drill hole that ran through the bead and into the other side of nacre.

Figure 2. The cross section (left) and microradiograph (right) images of the same sample revealed the varied components of the bead cultured pearl and NFC chip. Photos by Diego Sanchez (left) and Artitaya Homkrajae (right).
Real-time microradiography (RTX) revealed that the electronic devices embedded in the two halves and in the intact pearl samples were of the same kind. The device was composed of a high-density radio-opaque core (measuring approximately 5.10 × 3.26 mm) that appeared white in the RTX image and as an opaque black filler in the cross sections. An antenna could be seen wrapped around the core, and a circuit board was connected to the end of the antenna (figure 2). Chemical analysis of these components using laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) revealed that the black core was composed of a high-iron (Fe) material, which was confirmed using a magnet. The bronze-colored antenna and circuit board were identified as copper. The device was held in place in the large drill hole with a transparent near-colorless resin-like material containing numerous gas bubbles. The drill hole areas were worked (cut) to a flattened surface and plugged with a white plastic-like material, which was subsequently re-drilled with a smaller drill hole. Although the large drill hole was placed in the center, it did not affect the origin determination of the pearl. The shell bead nucleus and the device contained within could be observed using RTX, even for the intact sample. The pearl’s shape was certainly impacted by the cut surface, and the classifications for color, overtone, luster, and surface would be based on the remaining nacreous surface.
The electronic device appeared to be a near-field-communication (NFC) chip, which is a short-range wireless connectivity technology based on traditional radio-frequency identification (RFID) (https://nfc-forum.org/what-is-nfc/about-the-technology). NFC technology allows data transfer between two NFC-enabled devices through electromagnetic radio fields within a very short distance, either by physically touching or being within a few centimeters of each other. NFC chips are passive and do not need to have a power source of their own, though the antenna can be coupled with an active device such as a smartphone via an electromagnetic field. The chip is used to store digital information such as images, video, text, and audio, which are accessed through an app due to limited memory. To the best of our knowledge, this technology was first incorporated within pearl jewelry by Galatea: Jewelry by Artist and marketed under the name “Momento” (https://www.momentogem.com). However, the NFC chip embedded in the intact pearl sample in this study was not compatible with the Galatea Momento smartphone application.
So far, GIA has observed three kinds of electronic devices in cultured pearls. The first device encountered was an RFID chip implanted inside a shell nucleus by Fukai Shell Nucleus prior to the culturing process (“ID nuclei add value to pearls,” Hong Kong Jewellery, September 2013, pp. 62–64). The RFID technology is used to track and identify the pearl directly from farm to consumer. The second was a “capsule-like” feature found within an atypical P. margaritifera bead cultured pearl set in a ring that was submitted for identification at GIA Hong Kong, yet the reason for the device remains unknown (Spring 2020 Lab Notes, pp. 134–136). This NFC chip is the third kind and is used for wireless data transmission with an NFC-enabled device such as a mobile phone. The NFC chips were inserted into bead cultured pearls after they had been cultured, unlike the RFID chip. Therefore, the pearl is still classified as a bead cultured pearl on GIA’s pearl identification report. The presence of the device is mentioned in the comments section.
Technology is pervasive in our daily lives and can even influence how pearl jewelry is produced. Since cultured pearls are opaque, the implementation of such micro-technologies within them is a viable option. These innovative wearable technologies retain the external appearance of pearls while performing a specific function. Source: GIA @topic:5


Title: DNA Barcoding and Next-Generation Sequencing (NGS) of Freshwater Pearls Abstract: Twenty-two pearls of various kinds and species from various freshwater sources were used for the blind DNA study. Photo by Sood Oil (Judy) Chia.
Research efforts on the deoxyribonucleic acid (DNA) species identification of biogenic materials, in particular pearls, have been the focus of some gemological laboratories, including GIA’s, for several years (J.B. Meyer et al., “DNA fingerprinting of pearls to determine their origins,” PLOS ONE, Vol. 8, No. 10, 2013, e75606; K. Saruwatari et al., “DNA techniques applied to the identification of Pinctada fucata  pearls from Uwajima, Ehime Prefecture, Japan,” Spring 2018 G&G, pp. 40–50; K. Scarratt, CIBJO Special Pearl Report, 2019). Here we report on the findings of a study on the DNA analysis of cultured and natural freshwater pearls originating from both North America and China using the next-generation sequencing (NGS) technique, in collaboration with the Canadian Centre for DNA Barcoding at the University of Guelph.
A total of 22 freshwater pearl samples were subjected to DNA barcode analysis (see above). Nine American freshwater natural pearls (sample numbers 1, 2, 8, 12, 13, 15, 16, 17, and 18) and four American freshwater cultured pearls (sample numbers 3, 4, 9, and 10) from Gina Latendresse (American Pearl Company, Inc., Nashville, Tennessee), and nine Chinese freshwater cultured pearls (sample numbers 5, 6, 7, 11, 14, 19, 20, 21, and 22) from the GIA research collection were analyzed. The samples were either drilled with a hand drill using sterile techniques or crushed with a mortar and pestle using liquid nitrogen to obtain powder for analysis. Previously published DNA extraction protocols for pearls were modified to include newly designed primers for polymerase chain reaction (PCR) amplification and NGS. Only high-quality reads assigned to correct Ion Xpress MID (molecular identifier) tags were used in NGS data analysis. Negative PCR and negative extraction controls did not produce any valid sequencing data. Blast algorithms were utilized to match resulting operational taxonomic units to a reference library database for mitochondrial cytochrome c oxidase subunit I; results were imaged using MEGAN software. DNA sequences recovered from the unknown pearl samples were compared against the species sequence reference library in the Barcode of Life Data System, accessible at http://www.boldsystems.org, and compared against the National Center for Biotechnology Information database (https://www.ncbi.nlm.nih.gov).

DNA fragments from eight of the twenty-two samples were successfully recovered and identified. DNA-based species identification was highly consistent with the reported origin of the pearls (table 1). Results on the analyses of the 14 remaining samples were not successful, and no valid yield was recovered. This can be attributed to many factors, including insufficient DNA content due to limited sample size, or the elimination of trace DNA during the various routine pearl treatments known to be applied. While challenges remain on the extraction of DNA fragments from pearls, the results indicate that this technique can provide positive matches on individual pearls and prove which mollusk species they originated from, thus aiding in the identification of some challenging pearls or confirming mollusk origins in cases where greater detail may justify the time and expense of such analyses.
This joint research was previously presented at the 7th International Barcode of Life Conference (Genome, Vol. 60, No. 11, pp. 1003–1004). GIA will continue to investigate this field of research, which is proving to be a highly valuable supplementary technique in the gemological examination of pearls. Source: GIA @topic:5


Title: Three Unique Large Natural Pearls from Haliotis (Abalone) Species Abstract: Figure 1. Three unique abalone pearls are shown alongside a typical 12 mm golden South Sea bead-cultured pearl for comparison. Photo by Sood Oil (Judy) Chia.

Natural abalone pearls are produced by many species of the Haliotis genus, which are ear-shaped saltwater univalve gastropods. They may form in many different sizes and shapes, though they are commonly encountered in baroque shapes, often taking the form of elongated “horns” and “teeth.” The pearls are also notable for their high luster and attractive multicolored appearance, which is usually dominated by blue, green, or yellowish green bodycolors. GIA has reported on many Haliotis pearls in previous Lab Notes over the years (Fall 1984, p. 169; Spring 1996, pp. 47–49; Fall 2004, pp. 259–260; Spring 1993, p. 51).

Three large and unique abalone pearls from a client’s collection were recently submitted to the New York laboratory (figure 1). Each piece was remarkable in its own right. A button-shaped pearl, measuring approximately 26 × 24 mm with impressive vivid “peacock” blue and green hues, was set in a yellow metal brooch. The second piece, seen in figure 1 on the far right, was a loose abalone pearl weighing 66.83 ct and measuring approximately 42 × 26 × 19 mm with a striking resemblance to a fish’s head. The eye, mouth, and gill features were clearly outlined in the specimen, which possessed a smooth surface and subtle array of iridescent greenish yellow colors. The third piece, weighing 113.58 ct and measuring approximately 62 × 29 × 16 mm, was also loose and resembled the head of a snake. It exhibited strong iridescence with mottled patches of various colors similar to the pattern observed on the scaly skin of snakes.

Figure 2. All three specimens from figure 1 showed concentric and void-related internal structures typical of abalone pearls. Images by Surjit Dillon Wong.
Microradiography revealed characteristic Haliotis-related voids with concentric growth structures in all three pearls (figure 2). Two of the pearls also revealed an iodine-rich composition, which GIA has noted is a fairly consistent property of abalone pearls. Such internal structures, along with their distinctive multicolored orient, bubble-like (botryoidal) subsurface structure (figure 3), interesting chemical composition, and chalky greenish yellow fluorescence under long-wave UV are all characteristic of abalone pearls.

Figure 3. This photomicrograph shows the patches of color and botryoidal-like subsurface
structure characteristic of abalone pearls. Photomicrograph by Joyce Wing Yan Ho;
field of view 3.9 mm.
The various shapes are determined by where the pearls are formed within the body of the mollusk, and often mirror the form of the gonad (E. Strack, Pearls, Ruhle-Diebener-Verlag GmbH & Co. KG, Stuttgart, 2006). Examining all three specimens at the same time allowed us to see a range of colors and shapes possible in abalone pearls. We look forward to encountering more of these unusual pearls. Source: GIA @topic:5


Title: Large Natural Fossil Blister Pearls from Tridacna (Giant Clam) Species Abstract: Fossil pearls, first mentioned in 1723 in John Woodward’s “An essay towards a natural history of the earth and terrestrial bodies,” were described in greater detail by R. Bullen Newton in 1908 (“Fossil pearl-growths,” Journal of Molluscan Studies, Vol. 8, pp. 318–320). It is a rare occurrence to receive such pearls at GIA, which is why two large fossil blister pearls recently submitted to the New York laboratory immediately caught our attention.

According to the client, the pair of fossil blister pearls were found near Lunga Lunga, a region in southeastern Kenya bordering Tanzania. They were found attached to a fossilized giant clam shell that weighed approximately 297 kg and was discovered 4.3 meters below ground (figure 1) along with some fossilized corals. The shell, along with the attached pearls, was presented to the client as a gift from a local Digo tribe. It took a month to remove the entire shell from the ground. Similar fossilized giant clam shells have been recovered from areas along the Kenyan coastline (G. Accordi et al., “The raised coral reef complex of the Kenyan coast: Tridacna gigas U-series dates and geological implications,” Journal of African Earth Sciences, Vol. 58, No. 10, 2010, pp. 97–114). These two blister pearls were subsequently removed from the shell and submitted to GIA for identification after cleaning and removing the outermost fossilized debris.

Figure 1. Two natural fossil blister pearls attached to their giant clam host, courtesy of
Volker Bassen London Auction Rooms.
The blister pearls measured approximately 58 × 47 × 45 mm and 85 × 70 × 46 mm and weighed 758 ct and 1256 ct, respectively. The faces of these pearls had a porcelaneous appearance and were smoother than the bases, which were attached to the clam shell. These bases showed chalky rough surfaces and flared forms (figure 2). Numerous natural indentations and cavities were present on their surfaces. In some areas, subtle flame-like structures were also observed at 10× magnification with the use of fiber-optic lighting (figure 3).

Microradiography was not helpful owing to the specimens’ sizes, but Raman spectroscopy was able to detect calcite on both specimens and aragonite on the larger pearl, although it is possible there was aragonite in untested areas on the small pearl. The presence of aragonite in the larger pearl indicates that some of those structures had been replaced by calcite during fossilization.

Figure 2. The two natural fossil blister pearls after removal from the giant clam shell. The left image shows the face-up view, while the right image shows the base of the pearls, where the clam shell was previously attached. Photos by Sood Oil (Judy) Chia.

Figure 3. Porcelaneous and flame-like structures, seen here on the surface of the larger
fossil blister pearl, were observed in some areas under fiber-optic lighting. Photo by Joyce
Wing Yan Ho; field of view 15 mm.
According to the client, the shell in figure 1 was found in the upper layers of secondary fossil reef build-up, suggesting that it lived there during the later Pleistocene period. To the authors, the shell looks similar to that of the present-day Tridacna gigas giant clam, but the client stated that the clam was a precursor called Tridacna gigantea. The large size of these fossil blister pearls, their unique appearance, and the story behind their discovery proved fascinating, and offered valuable gemological and scientific information for future reference. Source: GIA @topic:5


Title: Partially Hollow Tridacna Blister Pearls with Shells Attached Abstract: Figure 1. Two Tridacna species shells with blister pearls in the adductor muscle area. Top: The shell of the specimen submitted to GIA’s Bangkok lab weighs 2.36 kg and measures 32.0 × 21.0 × 11.5 cm. The blister pearl measures 52.0 × 47.5 mm (depth unmeasurable). Photos by Nuttapol Kitdee. Bottom: The shell of the New York sample weighs 806.40 g and measures 20.0 × 13.5 × 9.5 cm. The blister pearl measures 80.00 × 50.0 mm (depth unmeasurable). Photos by Joyce WingYan Ho.

GIA sees pearls of all types submitted to its global laboratories. Almost all of them are either loose or mounted in jewelry pieces; however, exceptions are occasionally encountered. The submission of a blister pearl or blister still attached to its shell is such an example (Winter 2015 Lab Notes, pp. 432–434). In January 2017, the Bangkok laboratory received an intact shell with a pearl attached near the adductor muscle area (figure 1, top). The item weighed 2.36 kg. The shell measured 32.0 × 21.0 × 11.5 cm, while the pearl measured 52.0 × 47.5 mm. At the same time and by sheer coincidence, another shell with a similar appearance and a pearl attached to the same area (figure 1, bottom) was submitted to the New York laboratory. This item weighed 806.40 g and the shell measured 20.0 × 13.5 × 9.5 cm, while the pearl measured 80.0 × 50.0 mm.

The exterior of the shell submitted to Bangkok exhibited a light brownish color and appeared roughly triangular in outline with a wavy pattern of thin ridges in rows, while the interior was white to cream with a porcelain-like surface. According to the client, the shell was found in 2014 by fishermen off the coast of Kood Island, a district of Trat Province in eastern Thailand. The shell’s features are characteristic of Tridacna species mollusks, of which there are a number of varieties (U.E. Hernawan, “Taxonomy of Indonesian giant clams (Cardiidae, Tridacninae),” Biodiversitas, Vol. 13, No. 3, 2012, pp. 118–123).

As figure 1 (top right) shows, a blister pearl of similar color is prominently attached to the surface. Observation with a loupe and microscope confirmed that it was naturally attached and untreated. Microscopic examination using a fiber-optic light source confirmed the presence of flame structure on some surface areas of the shell and pearl, confirming their non-nacreous or porcelaneous nature. The pearl’s flame structure was short and patchy, while that seen on the shell was sharper and more defined. While the pearl’s nomenclature may be the source of some debate, we considered it to be a blister pearl, rather than a blister, based on its external appearance, position on the shell, and size (E. Strack, Pearls, Ruhle-Diebener-Verlag, Stuttgart, Germany, 2006, pp. 115–127). The shell and pearl were exposed to long-wave UV, with the shell showing a moderate to strong chalky blue reaction with yellowish orange patches near the lip area (figure 2, left), while the blister pearl exhibited a weak to moderate yellowish green color (figure 2, right). This demonstrates how fluorescence in samples may vary from area to area.

Figure 2. Exposure to long-wave UV produced a moderate to strong chalky blue reaction with yellowish orange patches in the shell of the Bangkok specimen (left) and a weak to moderate uneven chalky yellowish green reaction in the attached blister pearl (right). Photos by Promlikit Kessrapong and Kwanreun Lawanwong.
However, the most noteworthy feature of the Bangkok specimen was that when the shell was tilted or gently rocked from side to side, a liquid clearly moved within the blister pearl (figure 3, left). The liquid was not viscous and so was most likely water, rather than a thicker liquid such as oil. It is possible that seawater was trapped during the blister pearl’s formation or found its way into the “hollow” pearl at a later date. When fiber-optic light was used to illuminate the blister pearl, some of the light was transmitted and made the pearl appear translucent (figure 3, right). This, together with the trapped liquid, proved the pearl was at least partially hollow (see video at http://www.gia.edu/gems-gemology/tridacna-blister-pearls).

Figure 3. The blister pearl on the Bangkok submission shows a distinct boundary delineating the two phases (liquid and air) within the hollow pearl. The liquid part appears as a darker area and the air as a lighter area (left). Fiber-optic illumination reveals the boundary from a different perspective (right).
To see the extent of the Bangkok blister pearl’s void, we examined its internal structure using a real-time X-ray (RTX) machine. Although it was only possible to examine the pearl in one orientation owing to its position and size, the blister pearl quickly revealed its partially hollow form (figure 4, left). The various shades of gray within the white near-oval feature (solid pearl surface) prove that the blister pearl’s interior is full of organic matter and/or air since the X-rays passed through with very little obstruction. While hollow or partially hollow pearls—both nacreous and non-nacreous—are not new (N. Sturman, “Pearls with unpleasant odors,” GIA Laboratory, Bangkok, 2009, www.giathai.net/pdf/Pearls_with_unpleasant_odours.pdf), this is the first one GIA has encountered with such visible trapped liquid. Although the solid shell attached to the pearl displayed similar gray shades, this coloring relates more to the sample’s thickness than anything else. A few small rounded, darker gray patches are voids caused by parasites boring within the shell rather than by structures within the blister pearl.

Figure 4. RTX results for the Bangkok sample (left) revealed a hollow pearl with a near-oval white ring marking the solid outline of the pearl’s surface. Only parts of the New York pearl (right) were in the field of view at any one time due to its size. Neither appears to be entirely hollow; however, it was not possible to examine the pearls in other orientations due to their size and position on their hosts.
Void-like structures in whole or blister pearls from Tridacna species mollusks are not unusual (S. Singbamroong et al., “Microradiographic structures of natural non-nacreous pearls reportedly from Tridacna (clam) species,” Proceedings of the 5th GIT International Gem and Jewelry Conference, Pattaya, Thailand, pp. 200–222), and GIA has examined many voids in other non-nacreous pearls. The RTX results proved that the specimen described was a natural blister pearl attached to its shell.

The shell submitted to GIA’s New York laboratory is also noteworthy, not only for the coincidental submission, but also because the pearl was larger relative to its host’s size than the one examined in Bangkok. The baroque natural blister pearl attached to this rather more colorful shell was also partially hollow, although not to the degree of the Bangkok sample. As the RTX results in figure 4 (right) revealed, the partially hollow blister pearl had a complex internal structure and was less homogenous than the specimen submitted in Bangkok. Unfortunately, no provenance was supplied with the New York sample, so there is no record of where it was found.

Both GIA reports stated that the naturally attached feature on each shell was a natural blister pearl. Many such specimens examined at GIA’s labs are submitted as loose examples that have already been removed from their hosts, so it was a welcome change to handle these two shells. In addition, a comment was included on each report informing the clients of the pearl’s partially hollow nature and, in the case of the Bangkok submission, the presence of a liquid. The size and appearance of the shells submitted proved they were not Tridacna gigas (giant clam), and the report referred to the hosts as Tridacna species only. Source: GIA @topic:5


Title: Gemological and Chemical Characteristics of Natural Freshwater Pearls from the Mississippi River System Abstract: Figure 1. The natural freshwater pearls of various shapes and colors collected from the Mississippi River system, together with heelsplitter (Potamilus alatus, left), purple wartyback or purple pimpleback (Cyclonaias tuberculate, center), and bankclimber (Plectomerus dombeyanus, right) mussel shells. Photo by Diego Sanchez.

The Carlsbad laboratory received 854 natural freshwater pearls from Kari Anderson (Kari Pearls, Muscatine, Iowa), who stated that they were collected from the Mississippi River system (figure 1). Although the time and location of recovery and the mollusk species were not recorded, we were informed that all were recovered as a byproduct of the shelling business in the past couple of years. The samples ranged from 0.013 to 3.59 ct and measured from 1.63 × 1.19 mm to 9.87 × 8.52 × 5.89 mm. The shapes varied from baroque (the majority) to near-round, button, and oval. Many of the baroque pearls exhibited the unique “wing” or “feather” form (Anderson mentioned that the divers refer to these as “spike” pearls) typically associated with American natural freshwater pearls (J.L. Sweaney and J.R. Latendresse, “Freshwater pearls of North America,” Fall 1984 G&G, pp. 125–140). The wing pearls are elongated, with a roughly triangular shape, and usually taper to more pointed ends. Most possessed an uneven rippled surface along their lengths. The surface texture and shape of the wing pearls are identical to the lateral “teeth” areas found on the mussel shells that host these organic gems (figure 2, left).

Figure 2. Left: A mussel shell and pearl showing a strikingly similar appearance. The elongated wing pearl’s shape resembles the shape of the lateral “teeth” on the shell. Right: Iridescent rainbow surface colors, or orient, creating a beautiful shimmering appearance; field of view 7.19 mm. Photos by Diego Sanchez (left) and Artitaya Homkrajae (right).
The pearl colors also varied widely in hue, tone, and saturation. The range of hues included very light pink, purplish pink, orangy pink, brownish orange, and brownish purple to brown. Many displayed a pronounced orient effect (iridescence or multiple colors on or below the surfaces), creating a beautiful shimmering appearance (figure 2, right). Moreover, some exhibited high metallic-like surface reflections that resulted in excellent luster. Classifying the colors was often quite complex, as the overtone and orient were strong enough to affect the actual bodycolor and the combinations produced different colors when viewed from different angles. Experience has shown that in most cases a pearl’s color is directly related to the mussel species and the color of the shell’s interior, though water environment and the nutrients available during formation also play an important role. The heelsplitter (Potamilus alatus), purple wartyback or purple pimpleback (Cyclonaias tuberculate), and bankclimber (Plectomerus dombeyanus) mussel species shown in figure 1 possess pink and purple interior surfaces. All have been known to produce pearls with desirable color.
The lightly colored samples exhibited moderate to strong yellow or bluish yellow fluorescence when exposed to long-wave ultraviolet radiation (365 nm), while the darker samples exhibited the same colors with weaker intensities. X-ray fluorescence imaging was used to help check the growth environment. The majority of the samples fluoresced weak to strong greenish yellow due to manganese content, thus confirming their freshwater origin. As with the long-wave UV reactions, the darker samples displayed weaker reactions, and this fluorescence quenching is related to the concentration of coloring pigments present (H. Hänni et al., “X-ray luminescence, a valuable test in pearl identification,” Journal of Gemmology, Vol. 29, No. 5/6, 2005, pp. 325–329). A few of the samples also exhibited a moderate to strong orangy reaction in some surface areas.
One hundred samples encompassing a broad range of colors, shapes, surface qualities, and sizes were selected in order to study their internal structures and trace element concentrations using real-time microradiography (RTX) and laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS), respectively. The baroque pearls showed growth structures that followed their shapes. The number and visibility of these structures varied from pearl to pearl. In certain orientations the growth structures resembled “linear features” in some wing pearls. Dark organic-rich and void centers were observed in some of the symmetrically shaped samples (i.e., button and oval). Although void structures could be considered characteristic of non-bead cultured (NBC) pearls, the voids in these samples appeared ovoid and relatively small (e.g., figure 3) and unlike the “twisted” void-like structures typically encountered within freshwater NBC pearls. Chemical compositions were analyzed using the same parameters published in a recent study (A. Homkrajae et al., “Provenance discrimination of freshwater pearls by LA-ICP-MS and linear discriminant analysis (LDA),” Spring 2019 G&G, pp. 47–60). Three ablation spots were tested on each sample, and results for the 22 elements selected are shown in table 1. The majority contained high Mn content, as expected for freshwater pearls and corresponding with the X-ray fluorescence results seen from the majority. Only one sample showed Mn levels below 100 ppmw in two spots at 89.7 and 64.2 ppmw, which is unusual for this pearl type. Yet both spots matched positions for freshwater pearls in the ternary diagram of Ba, Mg, and Mn (see Homkrajae et al., 2019), indicating a likely freshwater origin. Chemical data for the analyzed spots, especially the four discriminator elements Na, Mn, Sr, and Ba (bolded in table 1), showed results comparable with those of the American natural (USA-NAT) pearls group previously reported. The majority of the analyzed spots fell within the same region as the USA-NAT group in the Sr and Na content plot (figure 4). Furthermore, the linear discriminant analysis (LDA) method developed during the previous study discriminated 70% of these samples as USA-NAT.

Figure 3. RTX images of a 0.27 ct oval pearl showing a growth ring with an ovoid feature in the center. Void structures may be encountered in natural and non-bead cultured (NBC) pearls, but this small void is unlike the twisted void-like structures typically observed in freshwater NBC pearls.

Figure 4. The majority of the analyzed spots (USA-LP) fell within the same region as those from American natural (USA-NAT) pearls in the chemical plotting of Sr and Na content reported in Homkrajae et al. (2019). Red spots represent results for American cultured (USA-CUL) pearls and green spots equate to Chinese NBC (CH-NBC) pearl samples.

Pearls exhibiting six different colors—pink, purplish pink, orangy pink, pinkish purple, brownish orange, and orangy brown—were selected in order to study their spectroscopic characteristics. Apart from the brownish orange sample, each possessed orient. The analysis was conducted on the most homogeneously colored area of each sample. Raman spectroscopic analysis with a 514 nm argon-ion laser revealed aragonite peaks at 701, 703, and 1085 cm–1 along with strong polyene peaks between the approximate ranges 1119–1126 and 1503–1508 cm–1. UV-Vis reflectance spectra were recorded from 250 to 800 nm, and each spectrum revealed a clear absorption feature at about 280 nm, possibly associated with the protein conchiolin and usually observed in nacreous pearls (figure 5). The reflectance patterns of the pearls are associated with the bodycolors, and the reflectance levels decreased as the sample color became more saturated. The samples with a pink component showed reflection minima in the blue to yellow range corresponding to their bodycolors, with a reflection minimum centered around 506 nm. The results corresponded with previous findings on natural-color freshwater cultured pearls from Hyriopsis species (S. Karampelas et al., “Role of polyenes in the coloration of cultured freshwater pearls,” European Journal of Mineralogy, Vol. 21, No. 1, 2009, pp. 85–97; A. Abduriyim, “Cultured pearls from Lake Kasumigaura: Production and gemological characteristics,” Summer 2018 G&G, pp. 166–183). Surface observations and spectroscopic studies did not reveal any sign of color treatment, which indicates the pearls’ natural color origin.

Figure 5. UV-Vis reflectance spectra of six representative pearls revealed a clear absorption feature at approximately 280 nm that is likely associated with the protein conchiolin. Each spectrum showed absorption features in the visible region related to the pearl’s bodycolor. The samples with pink component revealed a similar absorption feature from blue to yellow range and centered around 506 nm. The intensity of the absorption increase is related to saturation of the colors. The spectra are vertically offset for clarity.
The Mississippi River and its tributaries are renowned for the diversity of native American mussels found in their waters. The extensive variety of species from the Unionidae family continues to produce a variety of colored natural pearls. This was a great opportunity to study and document the gemological and chemical characteristics of these unique freshwater natural pearls. The data collected enlarges GIA’s pearl identification database and will provide useful reference material in the years to come. Source: GIA @topic:5


Title: GIA Field Gemologists Visit Pearl Farms Near Mergui, Myanmar Abstract: Culturing Pearls in Mergui, Myanmar

	Discover Myanmar’s South Sea cultured pearl farms with GIA field gemologists.

	Travel Myanmar’s azure waters with GIA field gemologists in search of that country’s South Sea cultured pearls. As you journey to pearl farming areas off the Mergui archipelago, you’ll witness the cultivation of gold-lipped oysters—Pinctada maxima—including the process of nucleating the mollusks.

	The Mergui archipelago consists of more than 800 islands, off the far southern coast of Myanmar (Burma), in the warm waters of the Andaman Sea. The expedition visited the “Myanmar Ocean” pearl farming operation to witness South Sea cultured pearl production and to collect research samples from that remote region.

	You’ll venture underwater with the GIA team, to see the farm’s oysters in their mesh baskets. “Some people say that the best golden South Sea pearls are farmed here,” says Pardieu. The environment is largely unspoiled and conditions are ideal for pearl cultivation.

	You’ll also catch a glimpse of the lives of one of Myanmar’s ethnic minorities, the Moken—sometimes called “Sea Gypsies.”  They still lead a traditional life centered on fishing and boat building.

	This GIA Field Expedition (FE63) took place in March 2014. Besides Pardieu, the participants were cameraman Didier Gruel, pearl department senior manager Nick Sturman, and Staff Gemologist Areeya Manustrong. Source: GIA @topic:5


Title: Spectral Characteristics of Pinctada Mazatlanica and Pinctada Margaritifera Pearl Oyster Species Abstract: Figure 1. These Pinctada mazatlanica shells were obtained from Mexico. Left: The shell has a rounded outline, with a nearly equal height and width. The exterior surface exhibits alternating yellowish brown and dark greenish gray colors, with whitish blotches fanning out from the center. Right: The interior view of the shell on the left alongside a smaller example showing a yellowish green nacreous rim with a distinct orient. Photos by Lhapsin Nillapat.
Pinctada margaritifera is a well-known mollusk species of the Indo-Pacific region that produces gray to black pearls. Cultured pearls from the mollusk are often referred to as “Tahitian” in the market. Both natural and cultured P. margaritifera pearls are noted for their characteristic UV-visible spectra. The typical reflectance feature at 700 nm is a key identification attribute for this species (K. Wada, “Spectral characteristics of pearls,” Gemmological Society of Japan, Vol. 10, No. 4, 1983, pp. 3–11, in Japanese).

Pinctada mazatlanica, the so-called Panamanian pearl oyster, is a species closely related with P. margaritifera. Although P. mazatlanica was originally classified as a subspecies of P. margaritifera (R.L. Cunha et al., “Evolutionary patterns in pearl oysters of the genus Pinctada (Bivalvia: Pteriidae),” Marine Biotechnology, Vol. 3, No. 2, 2011, pp. 181–192), in 1961, the taxonomy of the Pinctada genus was revised, and P. mazatlanica was listed as a distinct species due to different shell characteristics and geographical occurrence. P. mazatlanica is extensively distributed along the western coast of the Americas from Mexico to Peru and around the Galapagos Islands. It is considered a native pearl oyster species of the Gulf of California in Mexico and around the Archipelago de las Perlas in the Gulf of Panama (G.F. Kunz and C.H. Stevenson, The Book of the Pearl, The Century Co., New York, 1908, p. 69). The spectroscopic characteristics of this species were believed to be similar to P. margaritifera (Winter 2005 Lab Notes, p. 347), yet this author was unable to find any recorded spectra in the literature.

GIA’s Bangkok laboratory recently studied three P. mazatlanica shells from Mexico (two are shown in figure 1). These shells appeared to have morphology between P. maxima and P. margaritifera mollusks (P. C. Southgate and J.S. Lucas, The Pearl Oyster, Elsevier, Oxford, 2008, p. 60). The rounded outlines were similar to those of P. maxima; in each, the shell’s height was almost equal to the width. The color of the outer surfaces alternated from yellowish brown to dark greenish gray, with rays of whitish blotches fanning out from the center. The inner nacreous rims ranged from yellowish green to dark gray with visibly iridescent overtones resembling P. margaritifera. To investigate reflectance UV-visible spectral characteristics in the dark and light nacreous areas, three pieces were cut from one of the shells (figure 2).

Figure 2. The lip area of one P. mazatlanica shell was cut into three pieces to investigate
the reflectance spectral characteristics in the dark and light nacreous areas. Photo by
Lhapsin Nillapat.
The dark gray nacre of all the samples exhibited the same spectral pattern as those recorded from naturally colored gray to black nacre of P. margaritifera shells and pearls. The reflectance feature at 700 nm was consistently present in these samples, together with a uroporphyrin feature at 405 nm (figure 3). Uroporphyrin has been established as one type of pigmentation responsible for gray to black tones in some pearl oyster species (Y. Iwahashi and S. Akamatsu, “Porphyrin pigment in black-lip pearls and its application to pearl identification,” Fisheries Science, Vol. 60, No. 1, 1994, pp. 69–71). However, the feature at 495 nm that is often displayed in natural dark-colored nacre from P. margaritifera was not present in these samples, while the spectra collected in white to silver areas lacked the 405 and 700 nm characteristics. The spectra were relatively featureless, with no significant reflectance showing in the visible region. This was in keeping with results obtained from the white to silver nacre of P. maxima and P. margaritifera shells and pearls (S. Elen, “Identification of yellow cultured pearls from the black-lipped oyster Pinctada margaritifera,” Spring 2002 G&G, pp. 66–72).

Figure 3. UV-visible reflectance spectra of the darker gray nacre areas of all three
P. mazatlanica shell samples shown in figure 2 are similar to the spectrum from a
P. margaritifera pearl. All show a uroporphyrin feature at 405 nm and a feature at
700 nm, which is diagnostic of P. margaritifera. These spectra prove the similar
spectral characteristics between P. mazatlanica and P. margaritifera.
Further studies at GIA’s New York laboratory on P. mazatlanica shells from GIA’s Carlsbad collection confirmed these findings. Additionally, the yellow-green nacre close to the dark gray nacreous rim of the shell showed a broad trough from 330 to 460 nm. This consisted of features between 330 and 385 nm and between 385 and 460 nm. A clear feature at 700 nm was observed, but the one at 405 nm was not evident. The spectra are comparable with natural yellow P. margaritifera nacre samples (again, see Elen, 2002).

Photoluminescence (PL) spectra collected on the dark gray and yellow-green nacreous areas of all the samples showed bands at approximately 620, 650, and 680 nm. These same PL bands are observed in naturally colored nacre of P. margaritifera and Pteria sterna, as well as several colors of P. maxima nacre (S. Karampelas, “Spectral characteristics of natural-color saltwater cultured pearls from Pinctada maxima,” Fall 2012 G&G, pp. 193–197).

The reflectance and PL spectra from our samples prove the close relationship between P. mazatlanica and P. margaritifera. Pearls produced by these two black-lipped oyster species therefore share similar spectral characteristics. Source: GIA @topic:5


Title: Non-Bead-Cultured Pearls from Pinctada margaritifera Abstract: Gray to black cultured pearls from the Pinctada margaritifera mollusk, commonly referred to as "Tahitian pearls," are in great demand globally. These often have striking overtones or secondary hues such as green, pink, purple, or a combination of colors. The majority of commercially produced Tahitian pearls are from French Polynesia. They are typically bead cultured, but some non-bead-cultured (NBC) pearls also occur as a by-product and are very marketable in their own right.

A new report from GIA's Bangkok laboratory, "Non-Bead-Cultured Pearls from Pinctada margaritifera," examines a set of 120 NBC samples stated to be of Tahitian origin. Internal structures were examined using real-time microradiography (RTX) and X-ray computed microtomography (µ-CT). The authors also recorded the samples' UV-Visible, Raman, and photoluminescence (PL) spectra.

The results appear to indicate that these NBC pearls were cultured in Pinctada margaritifera mollusks, or at least were formed from mantle that incorporated the genes of this mollusk. The authors note that the various spectra and internal structures recorded in the study will provide valuable reference data on NBC pearls. Source: GIA @topic:5


Title: Atypical “Beading” in the Production of Cultured Pearls from Australian Pinctada maxima Abstract: Eleven of the atypical “bead” cultured pearls and one “keshi” produced from the authors’ experiments. Photo by Lhapsin Nillapat.

In 2011, the authors began to see cases of low-quality natural pearls being used as unconventional “beads” for cultured nacre growth. These natural pearls had been inserted into the gonads of Pinctada maxima along with a piece of donor mantle tissue, or in some cases into the cultured pearl sacs created by initial or subsequent operations, to facilitate the growth of cultured nacre on to their surfaces.

To better understand this deceptive “beading” process, the authors conducted a total of 91 experiments on Australian Pinctada maxima. In 75 of the experiments, atypical “beads” (including natural abalone, scallop, Pteria sterna, Pinna, drilled coral, and faceted sapphire) were inserted. The other 16 tests consisted of irritating, folding, or inserting tissue into the mantle.

The results of their investigations appear in a study titled “Experiments in Using Atypical ‘Beads’ and Mantle Interference in the Production of Cultured Pearls with Australian Pinctada maxima.”

The study presents real-time X-ray (RTX) and X-ray computed tomography (µ-CT) images of the resulting cultured pearl products. Of the 91 experimental operations, 23 proved successful in cultured nacre growth over the unconventional “beads” and forming “bead” cultured pearls. In most cases, the process could be readily identified with either RTX or µ-CT analysis. Source: GIA @topic:5


Title: Spectral Characteristics of Natural-Color Saltwater Cultured Pearls from Pinctada Maxima Abstract: Natural-color saltwater cultured pearls (SWCPs) from Pinctada maxima were studied using UV-Vis-NIR and PL spectroscopy to better understand the mechanisms of their coloration and to separate them from other SWCPs with similar natural colors. Several spectral features were observed, suggesting that the samples’ bodycolor is due to a mixture of pigments. Although similar spectral characteristics are observed in SWCPs from Pteria sterna and Pinctada margaritifera, subtle differences permit the identification of the host mollusk. Source: GIA @topic:5


Title: X-ray Computed Microtomography Applied to Pearls: Methodology, Advantages, and Limitations Abstract: X-ray computed microtomography reveals the internal features of pearls with great detail. This method is useful for identifying some of the natural or cultured pearls that are difficult to separate using traditional X-radiography. The long measurement time, the cost of the instrumentation, and the fact only one pearl at a time can be imaged are some of this method’s disadvantages.

	DATA DEPOSITORY

	Supplementary Videos and Images (see below)
	Summer, 2010

Depository Item 1

	Figures 1a, 1b, 1c3D model of Beaded Saltwater Cultured Pearl

	Videos showing slices taken in three directions through the 3D model of the beaded saltwater cultured pearl in figure 4 (sample GGL19). All sections show reconstruction artifacts due to rotation: fine circles in the horizontal section (a) and a blurry rotation axis in perpendicular sections (b and c).

Depository Item 2

	Figures 2a-2f3D model of Non-beaded Saltwater Cultured Pearl

	Videos showing slices taken in three directions of the 3D model (with and without shadows) of the non-beaded saltwater cultured pearl in figure 5 (sample SK-51). In the videos b, d, and f, structures produced by the grafted tissue have an inverted color; that is, these structures appear dark in the original videos (a, c, and e) instead of bright. All sections show reconstruction artifacts due to rotation.

Depository Item 3

	Figures 3a-3c3D model of Freshwater Natural Pearl

	Videos showing slices in three directions of the 3D model of the freshwater natural pearl in figure 6 (sample GGL03). All sections show reconstruction artifacts due to rotation.

Depository Item 4

	Figures 4a-4c3D Model of Saltwater Natural Pearl

	Videos showing slices in three directions of the 3D model of the saltwater natural pearl (sample SK-46) presented in the figure 7. All sections show reconstruction artifacts due to rotation.

Depository Item 5

	In this (a) gray-black half-drilled, drop-shaped, non-beaded freshwater cultured pearl
	from Hyriopsis spp. (sample SK-54), a characteristic comma-shaped structure caused
	by the grafted tissue was only visible in one direction in the radiographs (b). Tissue-related
	structures (i.e., undulating growth lines) are clearly visible only in the μ-CT images (c, d).

	Figures 5e-5j3D Model of Non-beaded Freshwater Cultured Pearl

	The videos show slices in three directions of the 3D model of this sample. In the videos b, d, and f, the tissue-related structures are shown with inverted colors (they appear bright). All sections show reconstruction artifacts due to rotation.

Depository Item 6

	In this near-round, non-beaded freshwater cultured pearl (a) from Hyriopsis spp.
	(sample GGL26), a mixture of structures representative of a cultured pearl are observed
	in the radiograph (b). The μ-CT images (c, d) suggest that these structures are related
	to more than one piece of grafted tissue.

	Figures 6e-6j3D Model of Non-beaded Freshwater Cultured Pearl

	This is more evident in two of the videos (f and j), where the tissue-related structures are shown with inverted colors (they appear bright). Photo by A. Spingardi. All sections show reconstruction artifacts due to rotation.

Depository Item 7

	These 3D μ-CT images of a half-drilled, drop-shaped, saltwater natural pearl from Pteria spp. (sample SK-61) show the pearl mounted (left) and unmounted (right). The metal produces artifacts that partially mask the internal features; the structures indicative of a natural origin are much more visible in the unmounted pearl. Source: GIA @topic:5


Title: New 3-D Software Expands GIA’s Pearl Identification Capabilities Abstract: 3-D modeling software helps researchers visualize the internal structure of this pearl. Image by Emiko Yazawa/GIA.

	Pearls are one of nature’s most beautiful and intriguing gems. They glow with life and warmth, connecting us to the life of a gem like no other. Whether natural or cultured, pearls possess a mystique and allure all their own.

	For much of its history, GIA has been collecting and studying pearls from around the world. Its scientists have used a variety of tools and techniques to help identify the different types of pearls, most notably X-ray images. But in the past few years, real-time X-ray microradiography (RTX) and computed X-ray microtomography (μ-CT) have provided the most advanced means of revealing internal structure and drawing useful conclusions on pearls the Institute examines. These images help GIA technicians and scientists determine whether a pearl is natural, bead-cultured, non-bead cultured, and so on. The addition of X-ray fluorescence and chemical analysis using energy-dispersive X-ray fluorescence (EDXRF) helps separate those of freshwater origin from their saltwater counterparts.

	Some pearls remain an identification challenge for even the most well-equipped laboratories. Researchers sometimes find surprises hidden inside—a piece of shell or other object that is difficult to identify. Until recently, they were only able to see a two-dimensional view of the pearl’s internal structure, which limited their ability to resolve the gem’s entire structure.

These μ-CT images were processed by GIA researchers and gemologists using 3-D software to further analyze the pearls’ internal structure. Photo by Jian Xin (Jae) Liao/GIA.

	That’s where the latest technology can step in to help.

	GIA recently acquired software that expands its ability to probe the internal features of pearls. This powerful research tool makes it possible to virtually explore, manipulate, extract and reconstruct specific areas of a pearl for analysis. It also gives researchers the ability to enhance the existing μ-CT data collected to see the details more clearly.

	Three examples demonstrate the potential of this software. The first shows one half of a well-defined shell that caused the natural pearl’s formation. The second example is of a pearl examined in the GIA laboratory in Bangkok and described in a recent Gems & Gemology Lab Note. It clearly shows the form of the central radiating structure, as well as the extraction capabilities of the software. The third shows a challenging structure that the software helps define more clearly.

	EXAMPLE 1

	The images below are conventional 2-D μ-CT slices of a pearl with a strange internal structure. Researchers suspected it was a piece of shell, but the exact shape or structure of the shell was hard to visualize.

The modeling software extracted the internal structure of this pearl from hundreds of μ-CT slices and reconstructed its three-dimensional shape.

Specific internal structures in the pearl were selected to reconstruct its 3-D shape, as shown from a screenshot of the software. The top left image is the 3-D model, while the others are 2-D slice images.

The 3-D image of the shell within the pearl provides much more information than the original 2-D X-ray images. Images by Chunhui Zhou.

	See the video of the internal shell.

	3-D Model of Shell in Pearl

	This video shows 3-D imaging of a shell within a pearl.

	EXAMPLE 2

	This pearl contains a structure thought to be a tiny organism called a foraminifera.

These examples are known as star sands, marine protozoa that belong to the same order as foraminifera and once lived on the ocean floor. While not usually associated with pearl formation, foraminifera were recorded in pearls as early as 1980 (A.E. Farn, “Notes from the Laboratory,” The Journal of Gemmology, Vol. 17, No. 4, 1980, pp. 225–228). Image by Emiko Yazawa/GIA.

The 3-D software makes it possible to extract and reconstruct the internal features to further support our opinion. The bumpy, uneven surface strongly resembles the structure of a foraminifera. Image by Emiko Yazawa.

	See the video of the internal foraminifera.

	Foraminifera Structure in Pearl

	This video shows 3-D imaging of a foraminifera structure within a pearl.

EXAMPLE 3

	The software also has the potential to analyze other unusual structures within a pearl. The following example is a freshwater pearl with a large internal void, along with an associated white growth feature that is connected to the main solid portion. The 3-D model of the pearl after segmentation provides much more information on the overall shape and size of the void components. By observing the shape of the entire void, a clearer understanding of the pearl’s identity emerges. This gives researchers an opportunity to analyze the internal structure of both natural and cultured pearls in a way that wasn’t possible before.

Left: A 2-D μ-CT slice of a reportedly natural freshwater pearl shows unusual void and growth structures. Right: The 3-D model generated using the μ-CT slices shows the outer transparent area as the white growth structure, while the red area represents the black void component and the green area is the boundary between the white growth and the void structures. Image by Emiko Yazawa.

	GIA researchers continue to explore these fascinating internal structures as part of the Institute’s long-term research into the “Queen of Gems.” The new 3-D software is the latest tool at their disposal. Delving into these mysteries will further our understanding and support the research-based identification and evaluation of pearls. As GIA researchers master the capabilities of this powerful software tool, they can apply their experience to these more challenging pearls. Source: GIA @topic:5


Title: Identification of Yellow Cultured Pearls from the Black-Lipped Oyster Pinctada Margaritifera Abstract: Although the Pinctada margaritifera oyster usually is associated with the black pearls cultured in French Polynesia, it also can produce attractive large yellow cultured pearls, among other colors. An absorption feature at 700 nm can be used to separate these yellow cultured pearls from their more common counterparts produced in the South Seas by the Pinctada maxima. This absorption feature previously has been attributed to the presence of black pigments, and has been reported as an identifying characteristic of black cultured pearls from the P. margaritifera. An additional absorption feature in the UV region, between 330 and 385 nm, is indicative of natural yellow color in cultured pearls from the P. margaritifera. Source: GIA @topic:5


Title: Two Large Natural Pearls Reportedly from Spondylus and Trochoidea Species Mollusks Abstract: Figure 1. Left: A large natural pearl reportedly from a Spondylus species. Right: A large natural pearl reportedly from a Trochoidea species. Courtesy of Sunghee Caccavo.

In a Fall 2014 Lab Note (pp. 241–242), GIA reported on four natural pearls ranging from 5.72 to 12.40 ct that were reportedly from a Spondylus (thorny oyster) species. These interesting non-nacreous pearls showed porcelaneous surfaces with unique bluish flame structures. Another even larger natural pearl, also reportedly from a Spondylus species, was recently submitted to the New York laboratory for identification. This pearl measured approximately 24 × 16 mm and weighed 42.96 ct (figure 1, left). It was formed in an attractive drop shape with a homogeneous yellow-brown bodycolor, abundant surface grooves, and a distinct bluish flame structure (figure 2). As with previous examples, microradiography showed only a tight structure, lacking obvious growth arcs. In addition, aragonite and natural polyenic pigment peaks were detected by Raman spectroscopy. Its unique appearance, coloration, and bluish tinted flame structures consistent with Spondylus pearls we previously reported. There is no known cultured pearl from this species, and the tight structure is commonly seen in other non-nacreous pearls, which further confirmed its natural origin.

Figure 2. Distinct bluish flame structures were observed on this large non-nacreous pearl, similar to previously studied samples that also reportedly formed within Spondylus (thorny) oysters. Photo by Joyce Wing Yan Ho; field of view 7.9 mm.

	The same client also submitted a large natural nacreous pearl reportedly from an unknown Trochoidea (turban snail) species (figure 1, right). The specimen, which measured approximately 27 × 19 × 12 mm and weighed 39.30 ct, had a cream color, high luster, and strong orient. Its smooth surface showed a unique wavy pattern. Previously GIA reported on a natural pearl from the turban snail species Astraea undosa that also showed high luster and strong iridescent colors, with an undulating wave-like pattern (Winter 2003 GNI, pp. 332–334). Both pearls share many common characteristics, and their appearances closely resemble one another.

	Our client claimed that the Spondylus pearl is from Baja, Mexico; the turban pearl is from Mexico’s Pacific coast. Although it is extremely challenging to identify the exact mollusk species these rare pearls originated from, their unique and interesting appearances are consistent with previously studied materials of similar claims. Regardless of their exact origin, these beautiful large natural pearls prove just how wonderful Mother Nature is at creating spectacular wonders of great variety and eye-pleasing form. Source: GIA @topic:5


Title: From Single Source to Global Free Market: The Transformation of the Cultured Pearl Industry Abstract: Over the past 15 years a combination of market forces, environmental events, and scientific research has radically changed the cultured pearl industry from a single commodity dominated by one producer to a highly diverse industry operating throughout the Pacific region. The new products, consistent quality, and broader marketing programs in turn led major designers and retailers in the United States and Europe to take a much greater interest in cultured pearls. During this period, consumer interest has expanded from the traditional small and medium white round Japanese akoya cultured pearl to the larger South Sea and Tahitian goods, as well as numerous previously “undesirable” shapes and colors. Source: GIA @topic:5


Title: Update on the Identification of Treated “Golden” South Sea Cultured Pearls Abstract: Most of the “golden” South Sea cultured pearls in a single strand were found to exhibit unusual brownish orange fluorescence to long-wave UV radiation and atypical absorption features at 405 nm and 558 nm. On the basis of these features and visual examination, 33 of the 35 cultured pearls were identified as color treated. This study demonstrates how atypical absorption features, particularly in the blue region of the spectrum, can be used to positively identify color treatment, even in the presence of the 330–385 nm UV absorption feature characteristic of natural-color “golden” pearls from the Pinctada maxima mollusk. Source: GIA @topic:5


Title: History of Pearling in La Paz Bay, South Baja California Abstract: The history of Baja California has been closely tied to the exploitation of pearls since the 16th century. Using rudimentary diving techniques for most of this era, European and Mexican entrepreneurs recovered vast amounts of fine, dark pearls from this region. However, years of overfishing inevitably led to decades when the oyster beds were all but barren. Introduction of the diving suit in the 19th century extended the depth of the beds that could be fished, but overexploitation continued largely unchecked. Cultivation of the pearl oyster Pinctada mazatlanica by Gaston Vives, between 1903 and 1914, greatly slowed exhaustion of the natural stock. His company, CCCP, represented the world's first large-scale cultivation of pearl oysters, and many of Vives's discoveries are used today in renewed pearl-oyster cultivation and pearl-culturing activities in Baja California. Source: GIA @topic:5


Title: Winter 2017 G&G: Cullinan-Like Superdeep Diamonds, the Artistic  Exquisite Gem Carvings of the Dreher Family, and Matrix-Matched Corundum Standards Abstract: The rough diamond shown on the cover, the 812 ct Constellation, was recovered from the Karowe mine in Botswana in November 2015. It is currently the sixth-largest gem-quality rough diamond ever recorded. It was sold in May 2016 for $63.1 million, the highest price paid for a rough diamond to date. The size, near absence of inclusions, low nitrogen content, shape, and surface texture place it in a special variety known as CLIPPIR diamonds, which are reviewed in the lead article in this issue. Diamonds such as the Constellation, which grow in a geologically distinct way, convey valuable information about the earth’s deep mantle. Photo by Jian Xin (Jae) Liao.

From diamonds that originate deep within the earth’s mantle to pearls cultured along Australia’s eastern coastline, the Winter 2017 issue of Gems & Gemology reports on the many facets of the gemological world. Articles include a look at the origin of Cullinan-like “superdeep” diamonds, the lifelike gem carvings of Gerd and Patrick Dreher, and the characteristics of Australian akoya cultured pearls. The Winter issue also introduces GIA’s new calibration standards sets  for analyzing the chemistry of corundum, compares two different types of detectors in microradiographic imaging of pearls, and features a chart showing inclusions in natural, synthetic, and treated ruby.
THE VERY DEEP ORIGIN OF THE WORLD’S BIGGEST DIAMONDS

Rough CLIPPIR diamonds have physical features akin to the historic Cullinan diamond, which forms the “C” of the CLIPPIR acronym. The size distribution for this variety of diamond is skewed toward large sizes, with the examples shown here ranging from 14 to 91 carats. In rough form, CLIPPIR diamonds are irregularly shaped rather than well-formed crystals and sometimes appear to be broken fragments of once larger diamonds. Photo by Robert Weldon/GIA; courtesy of Gem Diamonds Ltd.
The lead article of the Winter 2017 issue reviews the remarkable diamonds found deep in the earth’s convecting mantle. In a follow-up to his December 2016 article in Science magazine, Evan Smith and coauthors examine 83 of these large, pure, Cullinan-like diamonds, known for their high clarity and D color grades. The samples used in this paper, along with their inclusions and other properties, provide a glimpse into the earth’s geologic formation.
GEM VIRTUOSOS: THE DREHERS AND THEIR EXTRAORDINARY CARVINGS

This Gerd Dreher lily carving (2005) is from a single piece of Brazilian agate and measures 11.0 cm in length. His skills are on exhibit through his use of the material and his technique, such as the curled petals that demonstrate a wealth of detail even on their undersides. The leaf, stamen, and enameled pistil accents are crafted from 18K gold and set with diamonds. Patrick Dreher’s citrine mouse (2015), 6.0 cm in length, shows attention to the animal’s stance and demeanor as well as fine detail in the carving of the fur. Photo by Robert Weldon/GIA, courtesy of the William F. Larson family.
The German town of Idar-Oberstein is known for its gem cutting and carving industry. Coauthors Robert Weldon, Cathleen Jonathan, and Rose Tozer explore the town’s rich history and the carving tradition of the Dreher family, which has passed down its skills through thirteen generations. The work of contemporary masters Gerd and Patrick Dreher is the focus of this article, which is accompanied by online videos and slideshows.
AKOYA CULTURED PEARL FARMING IN EASTERN AUSTRALIA

A bracelet showing naturally colored blue, cream, yellow, and silver akoya cultured pearls from Broken Bay Pearls. Photo courtesy of Broken Bay Pearls Pty Ltd.
For two decades, akoya cultured pearls in a variety of colors have been produced from P. imbricata fucata mollusks on Australia’s eastern coast. In this article, Laura M. Otter and her coauthors detail the production and conduct the first gemological and mineralogical study of these pearls. Their study concludes that colored Australian akoyas can be separated from pearls produced by other mollusk species.
ACCURATE REPORTING OF KEY TRACE ELEMENTS IN RUBY AND SAPPHIRE USING MATRIX-MATCHED STANDARDS

One of GIA’s new LA-ICP-MS corundum calibration standards sets (set number 1); the epoxy disk containing the set is 1.5 inches in diameter. NIST SRM 610 and 612 glass standards are included to account for trace and non-trace elements, such as those found in inclusions, that were not incorporated into the synthetic sapphire crystals grown for standards. Photo by Jennifer Stone-Sundberg.
Trace element analysis is crucial to determining geographic origin of corundum. Jennifer Stone-Sundberg and a team of researchers have developed highly accurate calibration standards for chemical analysis at GIA using the LA-ICP-MS technique. These sets are designed for use in basic research and geographic origin reporting of ruby and sapphire.
REAL-TIME MICRORADIOGRAPHY OF PEARLS: A COMPARISON BETWEEN DETECTORS

Structures and principles of operation for an II (left) and an FPD (right). Modified after Ide et al.
Over the past twenty years, real-time X-ray microradiography (RTX) has largely replaced film-based X-ray imaging in the examination and identification of pearls. Stefanos Karampelas and his colleagues discuss the benefits and drawbacks of two different types of detectors used with RTX units.
CHART OF INCLUSIONS IN NATURAL, SYNTHETIC, AND TREATED RUBY

These rubies, a 16.68 mm rough and a 2.72 ct cushion cut, are from Myanmar. Photo by Robert Weldon/GIA, courtesy of the William F. Larson collection.
The third wall chart in a series documents inclusions often found in natural, synthetic, and treated emerald. Inclusion specialists Nathan Renfro, John Koivula, and Jonathan Muyal provided the 30 detailed photomicrographs in this chart.
LAB NOTES

This alexandrite cabochon appears brownish green in fluorescent light (left) and brownish purple in incandescent light (right). The cabochon shows chatoyancy under both forms of illumination due to light reflection from the shallow plane of dense fine parallel needles. Photos by Shunsuke Nagai.
Bulletins from GIA’s labs around the world include a cat’s-eye alexandrite with a unique inclusion pattern, a synthetic moissanite imitating rough diamond, and two natural sapphires with synthetic ruby overgrowth.
MICRO-WORLD

This Ethiopian opal contained an interesting inclusion scene consisting of a string of octahedral pyrite crystals and aragonite spheres. Photomicrograph by Charuwan Khowpong; field of view 1.40 mm.
G&G’s section on the inner world of gemstones features entries on aragonite spheres in Ethiopian opal,  twinned calcite inclusions in Mogok ruby, and shattuckite in quartz.
GEM NEWS INTERNATIONAL

Sixteen samples of facet-quality ruby (0.8–7.1 ct) from Longido, Tanzania. Photo by Sasithorn Engniwat.
The GNI section features a preliminary look at facet-grade ruby from Longido, Tanzania; an update on the Foxfire rough diamond, mined from Canada’s Diavik mine in 2015; and the testing of hydrophane opals dyed pink and blue.
2017 DR. EDWARD J. GÜBELIN MOST VALUABLE ARTICLE AWARD
G&G’s Most Valuable Article Award invites the journal’s readers to vote on the three most important articles from the previous year. Each completed ballot is entered into a drawing to win a one-year subscription to Gems & Gemology. To qualify for the drawing, please submit your votes for the 2017 MVA Award by Monday, March 12, 2018. Source: GIA @topic:7


Title: Fine-Quality Jadeite Jewelry Abstract: Figure 1. A selection of jewelry offered at Frank Lau’s booth. Jadeite of fine quality is not commonly seen in Tucson. Photo by Tao Hsu.

At this year’s Pueblo Gem and Mineral Show, the authors met Frank Lau from Frank Lau Jewelry. What caught the authors’ attention was the collection of fine-quality jadeite jewelry, which is predominantly found in the mainland China market but not in Tucson.
Mr. Lau’s booth offered a wide variety of jadeite including green, colorless, lavender, and red ranging in quality from medium to fine (figure 1). The jadeites are polished and carved in Guangzhou, China, while the jewelry is manufactured either in China or Seattle, where the store is located. Clients of the jadeite jewelry include both Chinese and Americans, with many repeat customers.

Figure 2. A rough jadeite boulder shows a very thin layer of reddish brown skin. Red jadeite is even rarer than the green variety. This boulder was offered at the Myanmar Gem Emporium. Photo by Tao Hsu.
While all of the jadeites are natural, Mr. Lau informed the authors that the reddish brown pendant is heated (figure 1). Reddish brown jadeite is extremely rare. This color is produced from a very thin layer of jadeite boulder (figure 2) leaving little material to make pieces of reasonable sizes. A good amount of reddish jadeite on the market is heated in air to oxidize the Fe-containing minerals to make the stone look red. This treatment is extremely hard to identify.
The colorless jadeite pieces, also called “ice jade,” are of very fine quality. This variety is popular with younger consumers. The exceptionally fine texture and relatively high transparency make it an alternative to the top-quality imperial green stones. When inclusions are present in the colorless jadeite, sellers describe them as “snowflakes” to attract buyers of different tastes (figure 3).

Figure 3. This colorless jadeite pendant is of very high transparency. Many sellers describe the whitish inclusions as “snowflakes.” Photo by Tao Hsu.
Mr. Lau sources his rough materials from Myanmar, though the skyrocketing price of rough makes this business increasingly difficult. He looks forward to the availability of more consumer-oriented jadeite education so Western consumers can better appreciate this gem. Source: GIA @topic:12


Title: Patania Jewelry Abstract: Figure 1. “Cleopatra” sterling silver necklace designed by Frank Patania Sr., featuring 99 Morenci turquoise stones. Photo by Robert Weldon; courtesy of Patania Jewelry.
At the GJX show, the Patania Jewelry booth featured striking silver jewelry, incorporating turquoise, red coral, and other gems, that stood out for its diversity in style. Some pieces had a strong Southwestern motif, while others blended in elements of modernism. A visit with the family at the booth while viewing designs from four generations of jewelers illustrated the diversity of styles.
The Patania family has been making jewelry in the southwestern United States since 1927. Frank Patania Sr. was only nine years old when he emigrated from Sicily to the United States in 1909 following a devastating earthquake. He opened the Thunderbird Shop in Santa Fe, New Mexico, after leaving New York following a bout of tuberculosis. His son Frank Jr., grandson Sam, and great-grandson Marco have all followed in his footsteps, each with his own distinct style.
The Thunderbird Shop was initially a curio shop selling Navajo and Pueblo silver jewelry along with Native American blankets, rugs, pottery, baskets, beadwork, and paintings. Frank Sr. started selling his own silver and turquoise art nouveau and Native American–inspired pieces such as jewelry, boxes, belt buckles, spoons, and letter openers out of the shop in the 1930s (figure 1). With the help of his wife, Aurora Patania, and other family members, the Thunderbird Shop grew and became a popular Santa Fe destination for prominent artists such as Georgia O’Keeffe. In fact, a 1933 Alfred Stieglitz photograph shows her wearing one of the Thunderbird Shop’s ridged silver bracelets, since renamed “Georgia” in her honor. Frank Sr. was known as a jewelry artist who brought a Mediterranean influence to silver and turquoise work. A second Thunderbird Shop was opened in Tucson in 1936.

Figure 2. One of two identical silver hollow-form bracelets by Frank Patania Jr. This cuff, known as both “Asymmetry” and “Twin Peaks,” was made around 1960 from six pieces of sterling silver using a small superstructure for support during the soldering process. The cuff weighs 100 g and measures 7 cm (2.75 in.) at its widest point. Photo by Robert Weldon; courtesy of Patania Jewelry.
As an apprentice to his father, Frank Jr., or “Pancho,” carried forward the silversmithing tradition, expanding it to incorporate modern design concepts. He began entering pieces in juried shows and developed a reputation as a top U.S. designer in the contemporary art movement. Frank Jr. was known for his meticulous craftsmanship, not only in jewelry but also in liturgical items and abstract sculptures. Two of his cuff bracelets are in the permanent collection of the Smithsonian American Art Museum. Figure 2 shows a duplicate of one—the “Asymmetry” hollow-form bracelet, also known as the “Twin Peaks” bracelet.

Figure 3. Nebula series necklace by Sam Patania, featuring sterling silver and spiderweb turquoise from the Number 8 mine in Nevada used for the pendant, while the necklace consists of turquoise beads from the Sleeping Beauty mine in Arizona. Photo by Sam Patania; courtesy of Patania Jewelry.
Sam Patania studied under Frank Jr. for 10 years starting at age 14. After this training period, Sam began branching out with his own designs featuring metal texturing and shaping methods such as repoussé. He credits Danish silversmith Georg Jensen and American artist William Spratling as his inspirations. This year at AGTA, Sam’s expertise and passion for texturing was evident at his demonstration during the MJSA Journal LIVE session. Figure 3 shows an example of his work with turquoise and silver.

Figure 4. Silver cuff by Marco Patania. Note the antique uranium glass marble beads that fluoresce under UV light (right) and the hand stamping on the interior. Photos by Robert Weldon; courtesy of Patania Jewelry.
Sam’s son Marco Patania is continuing the storied family tradition with silver forming, texturing, and stamping. Trained by his father for six years from the age of 13, with additional training at the Haystack School of Craft in Maine, Marco draws inspiration from the mid-century modern vibe and the unique role of Los Alamos, New Mexico, in nuclear research during that era. He pays homage to these themes by incorporating vintage uranium-containing glass marbles into modern cuff designs (figure 4). These marbles fluoresce a bright yellowish green under ultraviolet light.
For nearly a century, the Patania family has followed a tradition of excellence in Southwestern and modern jewelry craftsmanship. Source: GIA @topic:6