Title: Two Pen Pearls from Bahrain Abstract: Figure 1. Two pen pearls from Bahrain displayed on a pen shell originating from the same waters. Both the shell and the pearls exhibit a similar color pattern. Pearl A measures 4.65 × 4.25 mm and weighs 0.65 ct (left); Pearl B measures 4.86 × 4.34 mm and weighs 0.73 ct (right). Photo by Gaurav Bera.
Pen or pinna pearls, also known as the “fan clam,” originate from the marine bivalve mollusk belonging to the genus Pinna or Atrina. They are commonly found across the Indo-West Pacific region, from southeastern Africa to Melanesia and New Zealand, extending north to Japan and south to New South Wales. Additionally, they can be found in the Mediterranean Sea, the Red Sea, and the Arabian (Persian) Gulf. Typically, the shell size ranges from 10 to 60 cm, producing pearls measuring up to 11 mm and rarely even 16 mm. Most of these pearls are non-nacreous, displaying colors ranging from yellowish orange to brown and black, while the nacreous pearls exhibit a silvery surface (CIBJO Guide for Classifying Natural Pearls and Cultured Pearls, 2021).

Figure 2. A: Non-nacreous cellular structure with a significant surface-reaching crack in pearl A; field of view 0.5 mm. B: DiamondView image of the cellular structure on the black area on pearl A. C: Cellular structure with a network of subsurface cracking on pearl B; field of view 1.6 mm. D: DiamondView image of a spectacular greenish blue reaction of the cellular structure and the subsurface cracks on pearl B. Images by Karan Rajguru (A, B, and D) and Pfokreni Nipuni (C).
GIA’s Mumbai laboratory recently received two pen pearls for scientific examination. They were recovered by a renowned Bahraini diver from the shallow waters off Bahrain, fished at a depth of 2 meters in October 2023. Pearl A was a bicolor yellowish brown and black button shape, weighing 0.65 ct and measuring 4.65 × 4.25 mm, while pearl B was a yellowish brown near-button, weighing 0.73 ct and measuring 4.86 × 4.34 mm (figure 1). Visual observation showed significant surface-reaching cracks on pearl A (figure 2A) and a network of crazing or cracking due to the columnar structure on pearl B (figure 2C). When viewed under 40× magnification with a fiber-optic light, both exhibited a translucent non-nacreous surface with a columnar calcite structure, displaying a pseudo-hexagonal cellular outline (N. Sturman et al., “Observations on pearls reportedly from the Pinnidae family (pen pearls),” Fall 2014 G&G, pp. 202–215).
The pearls showed an inert reaction when exposed to X-ray fluorescence. Energy-dispersive X-ray fluorescence spectrometry on both revealed manganese levels below detection limits and 45 ppm and higher strontium levels of 1183 ppm and 1303 ppm, respectively, confirming their saltwater origin. Under long-wave ultraviolet radiation, the black area on pearl A was inert, while the yellowish brown area showed a moderate yellowish green reaction similar to that of pearl B. Faint patchy reddish areas were also observed under the translucent surface of pearl B, a reaction linked to a type of porphyrin pigment. When exposed to short-wave UV, pearl A was almost inert and pearl B showed a weaker yellowish green reaction. When examined by the deep-UV wavelength (<230 nm) of the DiamondView, both revealed a greenish blue reaction with a mosaic of fine cellular features of the columnar calcite structure (figure 2, B and D).

Figure 3. Top: RTX imaging of pearl A shows an acicular structure with significant surface-reaching cracks (A), and μ-CT imaging reveals a minute core (B). Bottom: RTX imaging of pearl B shows an acicular structure with a few subsurface cracks (C), and μ-CT imaging reveals a small central core (D).
Real-time X-ray microradiography (RTX) and X-ray computed microtomography (μ-CT) were conducted to study the internal structures. RTX imaging of pearl A revealed a fine acicular (radial) structure with significant surface-reaching cracks (figure 3A). A minute core was visible in μ-CT imaging (figure 3B). Pearl B also exhibited an acicular structure but with broader radiating lines than those observed in pearl A (figure 3C). Similarly, μ-CT imaging revealed a small central core with a few minor cracks (figure 3D). These structures corresponded with the columnar structure observed on their surfaces (Fall 2009 GNI, pp. 69–71).

Figure 4. Left: Cross section of pearl B after grinding, revealing an acicular structure with a dark inner ring and a small central core; field of view 2.1 mm. Right: Long-wave UV image of the cross section with the dark ring and core showing a brownish red reaction. Photos by Karan Rajguru.
Raman spectroscopy using 514 and 830 nm laser excitation revealed peaks for both pearls at 280 and 712 cm–1 as well as 1085 cm–1, indicative of calcite. The surface of pearl B was ground down, exposing a dark brown ring along with the acicular structure (figure 4, left). This ring was not visible in RTX or μ-CT imaging. Raman analysis on different spots of the ground pearl showed similar calcite peaks with a weak polyenic pigment peak at around 1437 cm–1. Photoluminescence analysis for both pearls revealed very weak bands at 620, 650, and 680 nm, indicating natural coloration. These bands were more distinct on the cross-sectional areas of pearl B. In addition, the dark brown central core and ring exhibited a brownish red reaction when viewed under long-wave UV radiation (figure 4, right), linked to a type of porphyrin pigment previously recorded in partially non-nacreous and nacreous pearls from the Pteria species (S. Karampelas and H. Abdulla, “Black non-nacreous natural pearls from Pteria sp.,” Journal of Gemmology, Vol. 35, No. 7, 2017, pp. 590–592) and in a Pinctada radiata shell with a partially non-nacreous blister pearl (Winter 2023 GNI, pp. 527–529).
Non-nacreous pen pearls are often priced lower than their nacreous counterparts from the Pinctada species, mainly due to their durability issues related to surface cracks. Although not desirable for jewelry purposes, they have been used as nuclei for producing atypical bead cultured pearls. In such cases, identification becomes very challenging due to their internal structure composed of natural acicular growth features. This submission provided an interesting opportunity to study these known pen pearl samples from Bahrain, a habitat shared with the popular Pinctada radiata mollusk species. Source: GIA @topic:5


Title: The Appeal of Non-Nacreous Pearls Abstract: Figure 1. Necklace featuring 37 conch pearls accented by 32 diamonds. Photo by Robert Weldon; courtesy of Aloha Pearls Hawaii.
Pearls never disappoint at the AGTA and GJX shows, and this year was no exception. While quantities were lower, a good supply of Tahitian, freshwater, and South Sea pearls was available. AGTA hosted a booth sponsored by Martin Rappaport featuring nacreous natural pearls from Bahrain, complete with reports from DANAT, the Bahrain Institute for Pearls & Gemstones. Of particular interest was a wide selection of natural non-nacreous pearls.
Several vendors at GJX offered non-nacreous conch pearls, with a smaller selection available at the AGTA show. Alec Rupp-Smith of Aloha Pearls Hawaii showed a fabulous graduated, mixed-color conch pearl necklace (figure 1) at both the GJX and Pueblo shows. The necklace featured 37 conch pearls with a total weight of 179 carats. Thirty-two diamonds, 9.06 carats total, were used as accents to the suite of pearls.

Figure 2. Melo “half pearl” weighing 57 ct. Photo by Robert Weldon; courtesy of Aloha Pearls Hawaii.
Rupp-Smith also presented an interesting Melo pearl from Myanmar (figure 2). The pearl was clearly cut in half, with the other half likely fabricated into jewelry. The remaining 57 ct half was polished to display the fine concentric rings used to help separate bead-nucleated cultured pearls from their natural counterparts, without the need for X-ray tomography. The banding was visible even without a loupe.
Somewhere in the Rainbow returned to the AGTA show to highlight recent acquisitions to their ever-growing collection. The mission of the collection is to bring education and enjoyment of fine colored gems to museums, galleries, and facilities dedicated to preserving the rarity and beauty of these minerals, gems, and articles of jewelry. The collection features pearls and colored stones from a wide contingent of designers from around the world. This year, three non-nacreous pearl creations stood out, sourced from Carlos Chanu, owner of California-based PCD Pearls.

Figure 3. Left: Cassis pearl necklace and convertible ring/brooch designed by Jim Grahl. Right: “Golash” brooch featuring fine quahog pearls. Photos by Robert Weldon; courtesy of the Somewhere in the Rainbow collection.
The first was a Cassis pearl suite consisting of a graduated necklace and convertible ring/brooch all fabricated in 18K gold and platinum by designer Jim Grahl of Balboa Island, California (figure 3, left). Chanu sourced the pearls from Europe over the course of one year. The layout of the necklace took a month to get just right, with a nicely matched blend of size, shape, and color. The ring/brooch pearl is one of the finest examples of Cassis known.
The second is the “Golash” brooch in figure 3 (right), named after the man who purchased it at an antique store in 2000 for $14, dates back to 1835 and was fabricated in the state of Rhode Island. Two rare quahog pearls (Mercenaria mercenaria) are set in the piece. At 13.5 ct and 13 mm, the larger, slightly button-shaped pearl has a glass-like surface and stunning color that make it an exceptional natural quahog pearl. Mercenaria pearls are rare, found as a byproduct of the clam fishing industry on the East Coast of the United States. The smaller, near-perfect drop-shape pearl measures nearly 9 × 7 mm and weighs 2.89 ct. Uniform natural drop pearls are among the rarest for any mollusk. As part of an international pearls exhibition, the “Golash” brooch toured the world from 2001 to 2008.

Figure 4. Quahog (Mercenaria mercenaria) pearl suite offered at the GJX show. Photo by Robert Weldon; courtesy of Pacific Coast Pearls.
Pacific Coast Pearls (Henderson, Nevada) brought an impressive array of natural pearls to GJX this year. After owner Wes Rankin found his first abalone pearl while diving off the coast of California, he spent the next decade collecting and purchasing pearls. This led to what has become one of the largest selections of natural pearls on the market today. At the show, co-owner Tish Rankin assembled an extraordinary suite of quahog pearls, just waiting for the right designer and inspiration to come along (figure 4). If only the humble clam had known. Source: GIA @topic:5


Title: Iridescent Imitation Pearl Abstract: Figure 1. This 8.03 ct brown oval imitation pearl resembled a pen pearl at first glance. Photo by Ravenya Atchalak.

Figure 2. Left: The material exhibited iridescent patches in its wispy, fibrous-like structure, resembling a lava cave covered in spiderwebs. Right: The iridescence phenomenon changed as the angle of view shifted under fiber-optic illumination. Photomicrographs by Ravenya Atchalak; fields of view 3.60 mm (left) and 1.88 mm (right).
An unusual brown oval specimen weighing 8.03 ct was recently submitted to GIA’s Bangkok laboratory for pearl identification. At first sight, the material resembled a pen pearl due to its dark color and non-nacreous appearance (figure 1). Upon closer inspection, however, it lacked the cellular structure characteristic of such pearls (N. Sturman et al., “Observations on pearls reportedly from the Pinnidae family (pen pearls),” Fall 2014 G&G, pp. 202–215). It instead displayed a wispy, fibrous-like pattern and mosaic patches of iridescence, resembling a lava cave sheathed in spiderwebs (figure 2, left). Under fiber-optic illumination, the iridescence phenomenon was visible within the body and varied as the item was moved and turned in the light (figure 2, right).
Observed externally were both a banding feature (commonly found in shell-related materials) and numerous lines across the base indicating it had been worked and altered from its original form. Real-time X-ray microradiography also revealed a distinct banded internal growth structure and parasite tubes. Raman spectroscopy identified this imitation pearl as calcite, and its bodycolor was likely treated. All this evidence, combined with energy-dispersive X-ray fluorescence analysis, indicated that the material was not a whole pearl but likely fashioned from the shell of a marine organism.
Although GIA has encountered a variety of imitation materials, this is the most fascinating specimen seen by the author. Source: GIA @topic:5


Title: Irradiated and Dyed Akoya Pearls Abstract: Figure 1. The two groups of reportedly irradiated akoya pearls used in this study. Photos by Sood Oil (Judy) Chia.
Since the 1960s, irradiation has been a known treatment for modifying the color of freshwater cultured pearls (Developments and Highlights at the Gem Trade Lab in Los Angeles, Spring 1967 G&G, pp. 153–154). It was found that freshwater shells and pearls contained higher amounts of manganese, which could be oxidized by irradiation to produce a darkened color (T. Tsujii, “The change of pearl colors by the irradiation with γ-ray or neutron ray,” Journal of Radiation Research, Vol. 4, No. 2-4, 1963, pp. 120–125). While saltwater pearls contain much less manganese than freshwater pearls, cultured saltwater akoya pearls could also be treated with irradiation. During treatment, the freshwater shell bead nuclei inside these cultured pearls would turn darker and cause the surface color, luster, and overtone to change (Winter 1988 Gem Trade Lab Notes, p. 244).
Recently, GIA’s New York laboratory obtained two groups of reportedly irradiated akoya pearls from two different vendors. These samples were either drilled or partially drilled, ranging from 3.82 mm to 8.15 mm in diameter and from 0.29 to 3.58 ct in weight (figure 1). They exhibited a variety of light to dark-toned gray with bluish and greenish bodycolors, with variously colored overtones.

Figure 2. Images showing obvious color concentrations at the drill holes of some samples with darkened bead nuclei (A and B), an unnatural dark patchy surface (C), and a darkened bead nucleus without color concentration (D). Photomicrographs by Emiko Yazawa; fields of view 4.79 mm (A and C) and 3.57 mm (B and D).
Real-time X-ray microradiography and energy-dispersive X-ray fluorescence confirmed that these were bead cultured pearls grown in a saltwater environment. No silver content was detected on any of the surfaces, suggesting that the colors of these pearls had not been modified by silver nitrate treatment. Upon microscopic examination, however, some of the samples displayed obvious color concentrations at their drill holes or unnatural patchy surface color distributions, while also revealing a darkened bead nucleus inside. On the other hand, some light-colored pearls did not possess color concentrations at the drill hole and only contained a darkened bead nucleus (figure 2).

Figure 3. Left to right: Cross sections of an irradiated akoya pearl, a white akoya pearl, and an irradiated and dyed akoya pearl. Photo by Emiko Yazawa; field of view 14.52 mm.
To further investigate the color origin, we cut several samples as well as a typical white akoya cultured pearl to compare their internal appearances (figure 3). The results confirmed that the reportedly irradiated pearls contained darkened bead nuclei showing brownish stripes rather than the usual white bead nucleus found in a white akoya pearl, indicative of irradiation treatment (Winter 1988 Gem Trade Lab Notes, p. 244). In addition, some samples exhibited a distinctly different color appearance at the nacre and drill-hole areas, indicating dye treatment.

Figure 4. Raman spectra of one sample’s surface nacre, nacre on the cross section, and bead nucleus, along with the surface nacre of a white akoya pearl for comparison. Unusual peaks were found in both nacre areas but not on the bead nucleus. Also shown are typical aragonite features at 702, 704, and 1086 cm–1.
Short-wave UV fluorescence spectroscopy confirmed that the akoya pearls may have been treated by any number of processes (C. Zhou et al., “Detection of color treatment and optical brightening in Chinese freshwater ‘Edison’ pearls,” Summer 2021 G&G, pp. 124–134), based on low fluorescence counts at around 320–360 nm. Raman spectroscopic analyses using 514 nm laser excitation revealed aragonite as the main component. Some treated pearls exhibited a series of unusual Raman shift peaks between 560 and 3200 cm–1 on the nacre (probably due to dye materials) but not on the darkened shell bead nucleus, suggesting two forms of treatment: dyeing and irradiation (figure 4).
Naturally colored gray pearls are usually light in color and tend to show uneven color distribution, making them difficult to match. Some grayish akoya pearls on the market have been treated to imitate these natural colors, since they command higher prices. While dye treatments are more easily detected by unnatural bodycolors, obvious color concentrations, and advanced testing, irradiation treatment is harder to detect since the nacre is not affected and the difference in bodycolor is subtle. Careful visual observation is necessary. The combination of irradiation and dye treatments in some of these treated pearls is not commonly encountered in our laboratory. Source: GIA @topic:5


Title: Assembled and Bead-Cultured Pearls Abstract: Figure 1. The 10.27 ct baroque cultured pearl exhibited a suspicious translucent ring at one end. Photo by Nuttapol Kitdee.

              A cream and white baroque pearl weighing 10.27 ct (figure 1) was recently submitted with seven other pearls to the Bangkok laboratory for a GIA Quality Assurance Report, which provides rapid identification for sorting purposes. The pearl appeared to have been assembled, as it possessed an odd translucent ring at one end, indicating where separate components had been joined together.

Prior to examination with real-time microradiography, it seemed likely that a shell bead nucleus was hidden from view, as the banded structure of a shell was observed in the translucent area when viewed with transmitted light from a fiber-optic light source. The transparent bonding agent used to join the two parts also contained black impurities (figure 2, left). Obvious gas bubbles were visible with a loupe or gemological microscope. Out of scientific interest, the pearl was also examined with X-ray fluorescence and DiamondView imaging. X-ray fluorescence showed a strong reaction in the damaged and repaired area, as would be expected because of its thinner nacre coverage. DiamondView imaging revealed the banding within the bead, the dark inclusions in the bonding agent, and the bonding agent itself (figure 2, right).

Figure 2. Left: Weak banding was faintly visible beneath the repaired and assembled area when viewed with a strong light source. Field of view 8 mm. Right: The banding was more noticeable in the DiamondView. Photo and DiamondView image by Areeya Manustrong.
Real-time microradiography revealed the bead nucleus as well as an extremely thin nacreous cap that had been used to cover the damaged bead. While X-ray computed microtomography (μ-CT) would not normally be needed to identify such an obviously bead-nucleated pearl, it was used to display the results with even greater clarity (figure 3). This analytical technique clearly showed the broken bead and an area where a new piece of nacre had been applied to repair the pearl. This would explain the mismatching translucent ring.

Figure 3. The broken bead and the nacreous cap applied to conceal the damage are clearly visible in this X-ray computed microtomography (μ-CT) slice.
This study demonstrated how the internal secrets of pearls can be revealed by a variety of techniques. Source: GIA @topic:5


Title: Pearl Care and Cleaning Guide Abstract: Pearl’s Mohs hardness is 2.5, so care should be taken not to scratch it.

                      Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with which one mineral can be scratched by another. But the Mohs scale is deceptive. The steps between the minerals are not evenly spaced. For example, diamond is only one number away, but it’s many times harder than gems in the corundum family.

Pearl is ranked 2.5 on the Mohs hardness scale, which means it’s very soft and easily scratched or abraded. But with reasonable care, pearl jewelry can be a lasting treasure.

Pearl’s toughness is usually good, but aging, dehydration, and sometimes excessive bleaching during initial processing might make some pearls more fragile.

Stability
High heat can burn cultured pearls or cause discoloration, splitting, or cracking.

Pearl is generally stable to light, but heat from intense light can cause dehydration and cracked nacre.

Pearl can be damaged by many chemicals and all acids. The list includes hair spray, perfume, cosmetics, and even perspiration.

Pearls might be dyed, impregnated, or coated. These treatments might alter over time. Bleaching and irradiation can be stable during normal wear.

	The colors of these freshwater cultured pearls are the result of dyeing. Dyed pearl colors can alter over time.

Cleaning
Pearls should never be cleaned in an ultrasonic or steam cleaner. It’s safe to use warm, soapy water for occasional, thorough cleaning. If the pearls are strung, be sure the string is completely dry before wearing.

For routine care, it’s best to wipe cultured pearls with a very soft, clean cloth after each wearing.

	With proper care cultured pearls can provide their owner with a lifetime of enjoyment.
	- Courtesy Albert Asher Pearl Co., NY Source: GIA @topic:5


Title: Tubular Feature in a Natural Pearl Abstract: Figure 1. This 1.27 ct white semi-baroque pearl exhibited a typical platy structure when examined under magnification. Photo by Lhapsin Nillapat.
Recently, GIA’s Bangkok laboratory received a 1.27 ct white semi-baroque pearl for pearl identification service (figure 1). Under 40× magnification, the surface exhibited typical nacreous overlapping aragonite platelets (platy structure).

Figure 2. Left: RTX image taken along the pearl’s thickest direction showing a stacked internal structure that could be misinterpreted as a void typically observed in non-bead cultured pearls. Center: RTX image from the flat direction revealing a tubular feature in the center. Right: μ-CT image revealing multiple interconnected rounded voids.
Real-time microradiography (RTX) revealed a tubular feature like a twisted tunnel at the center of the pearl, surrounded by fine growth arcs. When observed along the pearl’s thickest direction, the feature resembled a void or cavity-like structure (figure 2, left), similar to those found in non-bead cultured pearls (“The microradiographic structures of non-bead cultured pearls,” GIA Research News, November 20, 2009). However, when viewed from its flat direction (figure 2, center), the elongated tubular nature of the feature was inconsistent with the voids observed in non-bead cultured pearls. This inconsistency was further supported by X-ray computed microtomography (μ-CT), which showed multiple interconnected rounded voids (figure 2, right). When exposed to X-ray fluorescence, the pearl displayed an inert reaction indicative of a saltwater environment.

Figure 3. Similar tubular features observed in three reportedly natural saltwater pearls weighing 0.25, 0.34, and 0.44 ct, respectively, sourced from Pinctada radiata mollusks from the waters of Bahrain.
While this was the first time the lab had encountered a client submission with such a structure, similar structures were previously documented in three reference pearl samples from GIA’s research database. The three were reported to be natural Pinctada radiata pearls sourced from the waters of Bahrain; they were baroque and weighed 0.25, 0.34, and 0.44 ct (figure 3). Those samples showed a similar elongated twisted tubular feature at their center in RTX and μ-CT scan imaging, which helped confirm the natural origin of the examined pearl.

Figure 4. The 3D models generated using μ-CT scans revealed the tunnel-like feature (red) suspected of being parasite remnants or evidence of parasitic activity within the pearl.
To further study this tubular feature, three-dimensional models were created using specialized software to render the μ-CT scan images (“New 3-D software expands GIA’s pearl identification capabilities,” GIA Research News, May 13, 2016). The results from these models clearly showed that the central structure consisted of an elongated twisted tube. Based on the tubular formation presented, the feature is suspected to be formed by a burrowing parasite trapped in the center of the pearl (figure 4; see video below). Parasites of various types have been observed in both saltwater and freshwater bivalves, and certain worms have been known to use bivalve mollusks as their hosts. Notably, marine bivalve mollusks tend to be more prone to parasitic intrusions than freshwater mussels (E. Strack, Pearls, Rühle-Diebener-Verlag, Stuttgart, 2006, p. 116). Therefore, the presence of such tubular features in saltwater pearls indicates the potential infiltration of worm larvae into the mollusks’ mantle. These larvae—either dead, alive, or hibernating—may have subsequently become encapsulated by the mantle epithelial cells, leading to the formation of a pearl sac and eventually the creation of a pearl.

	Tubular Feature in a Natural Pearl Source: GIA @topic:5


Title: A Traditional Bombay Pearl Bunch Abstract: Figure 1. A Bombay bunch consisting of nine hanks and 553 high-quality natural pearls ranging from 3.83 to 5.72 mm. Photo by Gaurav Bera.
During the era when the maharajahs and maharanis ruled much of India, natural pearls were in great demand. In the nineteenth and early twentieth centuries, many merchants from the Middle East relocated to Bombay (now Mumbai) to benefit from this demand (R. Carter, Sea of Pearls, Arabian Publishing, London, 2012, pp. 169–175). Thus, it is no surprise that India has been a significant center of pearl manufacturing, processing, and trading for centuries. To showcase their high-quality pearls, traders and artisans in Bombay would sort the pearls, string them with silk threads, and tie them together at both ends using decorative metallic cords of various colors. These bunches were in great demand in the heyday of the natural pearl market and were sold as “Bombay bunches” (M. Manutchehr-Danai, Dictionary of Gems and Gemology, Springer, Berlin and Heidelberg, 2008, p. 101).
Recently, GIA’s Mumbai laboratory had the opportunity to examine an 80-year-old Bombay bunch inherited by one of the city’s established pearl families. The bunch consisted of 553 light cream round and near-round drilled pearls, strung in nine hanks, each containing four strands, with the exception of one hank with seven strands. The hanks were tied at both ends with white metal wires, together with silver and blue cords and tassels (figure 1). The pearls ranged from 3.83 to 5.72 mm, and the total weight of the bunch was approximately 80.51 g. The owner stated that the total weight of the pearls was approximately 130 chow (equivalent to 331.8 ct or 66.35 g). Chow is a system of converting weight into volume (The Pearl Blue Book, CIBJO, 2020).

Figure 2. Real-time microradiography images of eight pearls from the Bombay bunch revealing fine growth arcs and concentric ringed structures typical of those internal structures observed in Pinctada radiata pearls.
The strung pearls were perfectly matched in color and exhibited smooth surfaces with high luster. When viewed under 40× magnification, they all exhibited typical nacreous overlapping aragonite platelets. Their internal structures were examined by real-time microradiography. The majority revealed fine growth arcs and concentric ringed structures, while others revealed tight or minimal structures, some with small faint cores or light organic-rich cores (figure 2). It was evident that these were natural pearls from Pinctada-species mollusks, as their internal structures were very similar to those observed in Pinctada radiata pearls from the Arabian (Persian) Gulf when compared to GIA’s research database.
All pearls showed an inert reaction when exposed to optical X-ray fluorescence analysis. Energy-dispersive X-ray fluorescence spectrometry on a few samples revealed manganese values ranging from below detection limits to 30.7 ppm and strontium values of 1215 to 1989 ppm, consistent with a saltwater growth environment. Raman analysis using 514 nm excitation was also carried out on the surface of selected pearls showing a doublet at 702/705 cm–1 as well as a peak at 1085 cm–1, indicative of aragonite. Very weak polyenic pigment-related peaks at 1130 and 1530 cm–1 were also observed in a few of the pearls, likely associated with their light cream coloration (A. Al-Alawi et al., “Saltwater cultured pearls from Pinctada radiata in Abu Dhabi (United Arab Emirates),” Journal of Gemmology, Vol. 37, No. 2, 2020, pp. 164–179). The photoluminescence spectra under 514 nm excitation were also consistent with the Raman results and displayed high fluorescence together with the aragonite peaks, typical of most nacreous pearls. When exposed to long-wave ultraviolet light, the pearls showed a moderate blue reaction.
Historically, Bombay bunches were known to contain high-quality Pinctada radiata pearls fished from the Arabian (Persian) Gulf, commonly referred to as “Basra pearls” in the trade. Records indicate that the proportion of round pearls found in each natural pearl harvest today is less than 5% (H. Bari and D. Lam, Pearls, Skira, Milan, 2010, p. 43). Natural pearls are rare to find, and it can take decades to match a round pair of similar size, color, and luster. Encountering Bombay bunches in today’s market is a rarity, and it was a great opportunity for GIA Mumbai to examine such an interesting and memorable pearl submission. Source: GIA @topic:5


Title: An “Eye” on a Tridacninae Pearl Abstract: A 4.77 ct near-round white Tridacninae pearl exhibited an attractive sheen-like flame structure in a pattern resembling an eye when viewed in certain directions under a single white light source. Photomicrograph by Ravenya Atchalak; field of view 7.20 mm.
The Tridacninae subfamily of giant saltwater clams consists of two genera: Hippopus and Tridacna. These bivalve mollusks live only in the shallow waters of coral reefs in the tropical parts of the Indo-Pacific Ocean (E. Strack, Pearls, Rühle-Diebener-Verlag, Stuttgart, 2001, p. 60). They are known to produce white to cream non-nacreous pearls, with yellow or orange pearls less commonly found. Tridacninae pearls frequently exhibit a porcelain-like surface with a flame structure caused by stacked layers of aragonite lamellae in a crisscross fashion. The sheen-like effect occurs when those lamellae interact with light (H.A. Hänni, “Explaining the flame structure of non-nacreous pearls,” Australian Gemmologist, Vol. 24, No. 4, 2010, pp. 85–88). Pearls with such characteristics are known as porcelaneous pearls.
A 4.77 ct near-round white Tridacninae pearl (see above) recently examined by the author displayed a well-arranged flame structure consisting of a wide base with spiky ends radiating outward from the apex of the pearl. Microscopic examination under fiber-optic light revealed a remarkable feature. A dramatic pseudo-chatoyancy occurred over the luminous flames, creating the appearance of an eye staring back at the observer. Pearls with prominent flame structures and high sheen often contain striking features. Source: GIA @topic:5


Title: Natural Pipi Pearls from Tahiti Abstract: Figure 1. This parcel of rare natural pipi pearls was collected from French Polynesia. Note the exceptional golden pearl in the front with a diameter of 9.6 mm, believed to be the largest recorded pipi pearl. Courtesy of Bruno Arrighi/Croissy Pacific. Photo by Olivier Segura.

              Recently, the Laboratoire Français de Gemmologie (LFG) received a parcel of nearly 100 pearls submitted as natural pearls from Pinctada maculata. The owner (Bruno Arrighi, Croissy Pacific) specified that he had personally collected the parcel in French Polynesia during the past year (figure 1).

Pinctada maculata is a bivalve mollusk (figure 2) found in the Pacific Ocean, particularly near French Polynesia and the Cook Islands, that may produce rare “poe pipi” (better known as “pipi”) pearls. There were several unsuccessful attempts in the 1950s to produce cultured pipi specimens. Today, all such pearls are considered natural.

	Figure 2. The two valves of a typical Pinctada maculata shell specimen (interior and exterior view). Photo by Olivier Segura.
Different techniques are used to find the pearls. In one method, divers pick the largest shells of Pinctada maculata, then leave the shells on the beach in buckets full of salt water to putrefy. Three days later, the shells are selected and only the valves with blisters are kept. Deep in the bucket, one may occasionally find a few natural pearls. Kakaro (in the Paumotuan language) is considered the oldest technique for obtaining pipi pearls. During the dive, the largest shells are opened directly underwater to locate pearls.

Most pipi pearls range from orange to cream, gray, and white, but the typical and most sought-after color is a deep golden color. The size of the pearls generally ranges from 1 to 4 mm. The pearl in the forefront of figure 1 has one of the best golden colors possible. It is an exceptionally large specimen measuring 9.6 mm in diameter, which the contributors believe to be the largest size documented for a pipi pearl.

Microradiography reveals internal structures typical for natural pearls: onion-like stacking of aragonite layers possibly containing a calcitic core. Although Raman scattering, UV-visible reflectance, or UV luminescence spectrometry have helped identify the mollusk species in some cases, preliminary results with Pinctada maculata are still not conclusive. Hence, it is not possible to identify with certainty the exact mollusk from which these pearls came. Source: GIA @topic:5


Title: Assembled “Pearl” Filled with Wire Abstract: Figure 1. In this 10.97 ct baroque pearl, a suspect ring circling the surface is clearly visible. Photo by Nuttapol Kitdee.

The excitement of being the first person to observe a pearl’s interior is always foremost in one’s mind when performing microradiography tests on a newly submitted specimen. Baroque pearls in particular have a higher probability of revealing something unusual (see Fall 2013 G&G Lab Notes, pp. 172–173), since they often contain internal voids that are ideal for filling if exposed by damage or excessive drilling.

A light yellow and cream baroque pearl (figure 1), weighing 10.97 ct and measuring 12.74 × 11.60 × 11.14 mm, was recently submitted with seven others to the Bangkok laboratory for a GIA Quality Assurance Report, which provides rapid identification for sorting goods. Prior to microradiography, the pearl immediately appeared suspect because it was circled by an eye-visible band that indicated some “work” had likely been carried out. This was confirmed by examination with a loupe and microscope, which revealed a lustrous, transparent bonding agent. Small black impurities of an unknown nature were present in the bonding agent (figure 2). The type of work performed on the pearl was instantly confirmed by microradiography (figure 3). Looking at the microradiograph, it was obvious that two coiled wire fillings had been placed in the void between two hollow pearl pieces.

Figure 2. The area between the two parts assembled to form the “pearl” revealed creamy areas of deterioration where the bonding agent met the pearl components (left) and very small black impurities of an unknown nature trapped within the agent (left and right). Photomicrographs by Nick Sturman; magnified 70×.

Figure 3. The internal structure revealed two very distinct pieces of coiled wire (metal is radio-opaque) within voids whose outlines did not match. The mismatched outlines helped prove that two separate specimens were combined to form the new “pearl.” Image by Nanthaporn Somsa-ard.
This is not the first time that metal wire has been encountered in pearls (see K. Scarratt, “Notes from the Laboratory,” Journal of Gemmology, Vol. 20, 1986, p. 95), but it appears to be the first time two different hollowed halves have been assembled with a piece of wire in each. While there is little doubt that this specimen was fabricated to increase its weight and create a “single” pearl, the alterations were so severe that they removed critical internal structure, making the components difficult to identify. The two specimens may have been natural pearls with internal voids, bead-cultured pearls with voids around the bead (as is common), non-bead cultured pearls, or any combination of these. We therefore concluded that the “pearl” should be described as “undetermined” but filled. Source: GIA @topic:5


Title: Spotlight on Natural Nacreous Pearls Abstract: A pair of earrings with unoiled emeralds weighing about 8 ct total, natural pearls measuring 9.5–10.0 mm, unheated Burmese rubies weighing just under 5 ct total, and diamonds set in yellow gold. Photo courtesy of ProVockative Gems Inc.
A natural pearl forms in the interior of a mollusk within a naturally formed pearl sac without human intervention. The use of natural pearls goes back thousands of years, and these biogenic gem materials have been treasured in jewelry and adornment throughout human history. In general, pearls can be separated into two varieties based on surface structure: nacreous and non-nacreous. The nacreous pearls are more common in the market. These are formed by a layered structure of aragonite platelets together with organic substances as well as water, and they normally display a pearly luster.
At the AGTA show, Alex Vock of ProVockative Gems Inc. (New York City) shared some of his expertise in natural saltwater nacreous pearls. With more than 30 years in the business, he is considered an industry leader specializing in signed collectible jewelry, natural gemstones, and natural pearls. He had several pieces on display, including an attractive pair of natural pearl earrings set with unheated Burmese rubies and unoiled emeralds (see above).
Vock discussed the global market for natural nacreous pearls, noting that it was greatly diminished by the 1980s due to the prevalence of cultured pearls. However, regions such as many of the Gulf countries and India did not feel pressure from the cultured pearl market. These countries have led a resurgence of natural pearl’s popularity, specifically with Basra pearls. These originate in the Arabian (Persian) Gulf, and their namesake is the city of Basra in Iraq. Historically, Basra was the center of natural pearl commerce, with the greatest selection of natural pearls and the most informed dealers.
Vock mentioned that the most prized natural nacreous pearls today are from either the Gulf region or Australia. Currently, both regions produce what dealers describe as “new material,” which are freshly harvested natural pearls. Natural pearls form in the mantle of the pearl mollusk shells, whereas cultured saltwater pearls grow inside the gonad of the mollusks. Many natural pearls have a large flat surface, similar to a button shape, because they grow against the mantle. For that reason, round, oval, and drop-shaped pearls are rarest and most valuable.
When comparing pearls from the two regions, Vock explained, there are some differences. Basra pearls usually have a warmer bodycolor, while Australian pearls tend to be whiter. Also, Basra pearls are often rounder than their Australian counterparts. In fact, the Gulf region has the highest percentage of round natural nacreous pearls of any producing area. He credited this to the smaller shell of the Gulf region mollusks.

	Spotlight on Natural Nacreous Pearls

To see Alex Vock explain these common appearances with examples from his current collection, see the video above. Source: GIA @topic:5


Title: Exceptionally Rare Pearls from ECIJA Abstract: Figure 1. Left: The mother shell (Mercenaria mercenaria) and an 18K gold ring featuring a 14.43 × 14.63 mm lilac quahog pearl. Right: A rare collection of round quahog pearls ranging from 5.65 to 12.33 mm in diameter and in colors from white and beige to deep purple and tan. Photos by Robert Weldon; courtesy of ECIJA.
At the GJX show, ECIJA (Santa Barbara, California) displayed a variety of natural, wild, nacreous, and non-nacreous pearls, including conch, oyster, scallop, abalone, and quahog pearls. Only 0.2% of all pearls in the current market are natural (S. Karampelas et al., “Raman spectroscopy of natural and cultured pearls and pearl producing mollusc shells,” Journal of Raman Spectroscopy, Vol. 51, No. 9, 2019, pp. 1813–1821), and the authors found the non-nacreous collection especially notable.
ECIJA owner Aylene Norris and her husband, Jeremy Norris (Oasis Pearl), have been sourcing for 34 years and specialize in natural pearls. For the first time in Tucson, ECIJA displayed a collection of round quahog pearls (figure 1). Quahog pearls are produced in the bivalve mollusk Mercenaria mercenaria (figure 1, left), a type of saltwater clam native to the Atlantic Ocean. These non-nacreous pearls consist mainly of fibrous aragonite and organic matter. They are often not perfectly spherical but form irregular shapes such as button or baroque, making this set of round quahog pearls extremely rare (figure 1, right). Moreover, they exhibited an attractive and strong porcelaneous surface with sizes ranging from 5.65 to 12.33 mm in diameter. Quahog pearls are known for their unique range of colors, including white, beige, pink, lavender, purple, brown, and black. These 21 quahog pearls showed a wide color range, from white and beige to deep purple and tan (figure 1, right). According to Jeremy, lilac and deep purple are the most desirable and command the highest price. The color of a quahog pearl is determined by various factors, including the clam species and environmental and geochemical conditions.

Figure 2. This non-nacreous pearl weighing 16.44 ct and measuring 14.50 × 14.36 × 11.95 mm is reportedly from a Spondylus calcifer/limbatus mollusk from the Sea of Cortez in Baja California. Photo by Robert Weldon; courtesy of ECIJA.
Another rarity on display was a large (16.44 ct, 14.50 × 14.36 × 11.95 mm) deep purple, button-shaped non-nacreous pearl showing an obvious flame structure at its surface (figure 2). This pearl formed from one of the many Spondylus species, also known as “thorny” or “spiny” oysters, which are harvested on the western coast of the Americas as Spondylus princeps and Spondylus calcifer/limbatus. Reportedly from calcifer/limbatus from the Sea of Cortez in Baja California, the pearl’s large size, attractive purple color, and strong flame structure set its value. Previously, GIA has reported that flame structure is usually caused by subsurface to surface-reaching acicular inclusions (Fall 2016 Lab Notes, pp 303–304). Although several Spondylus pearls have been reported in G&G (Summer 2016 Micro-World, pp. 202–203; Fall 2016 Lab Notes, pp. 303–304), this is one of the largest and finest examples.
ECIJA also featured other nacreous and non-nacreous pearls for designers and buyers, including conch, scallop, and abalone pearls. Each of these species exhibits unique shapes and colors. Conch pearls are typically oval in shape and exhibit white, beige, brown, yellow, orange, pink, and red colors. They range in size from 1 mm to over 20 mm. Scallop pearls from Nodipecten nodosus, also known as “Lion’s Paw” or “Mano de Leon,” form button, oval, and baroque shapes that range from white and brown to rare purple or maroon colors. These exhibit beautiful reflective mosaic-like patterns on their surface. Abalone typically produce conical or baroque-shaped pearls exhibiting a combination of vibrant colors and a mirror-like luster. Symmetrical abalone pearls, especially in large sizes, are very rare.
While GIA has developed seven value factors to evaluate the quality of nacreous pearls (size, shape, color, luster, surface, nacre, and matching; see J.W.Y. Ho and S.C. Shih, “Pearl classification: The GIA 7 Pearl Value Factors,” Summer 2021 G&G, pp. 135–137 and accompanying wall chart), it is difficult to set the value for non-nacreous pearls due to their rarity and individual characteristics. In addition, demand dictates the value and price of rare pearls. An increasing demand for conch pearls has attracted buyers from all around the world. Jeremy indicated that conch pearls are especially popular in the European, U.S., and Asian markets. Deep pink to red pearls exhibiting a strong flame pattern are the most desirable and have doubled in value over the last 10 years, whereas pastel colors continue to be a more affordable solution for designers and collectors alike. Source: GIA @topic:5


Title: Cultured Pearl Market Update Abstract: Figure 1. Near-round to round small freshwater bead cultured pearls (approximately 2–4 mm) were widely available at the AGTA show in various colors including white, pink, purple, and orange. Photo by Artitaya Homkrajae; courtesy of Betty Sue King, King’s Ransom.
At the AGTA show, we spoke with several pearl dealers to acquire some insight into the current cultured pearl market. With demand for pearls trending upward in the secondary market, as reported by The Real Real in its Luxury Consignment Report in January 2023, it was easy to spot similar trends in other areas of the pearl market as well.
Bead cultured (BC) pearls are the result of the deliberate insertion of a bead nucleus along with a small piece of mantle tissue into the gonad of a living host mollusk to start the growth of the cultured pearl, a process known as nucleation or grafting. Non-bead cultured (NBC) pearls need only a piece of tissue implanted into the gonad or mantle of a host mollusk to form. A technique originally developed and successfully operated in Japan before adoption by other global operations including Australia, the Philippines, Indonesia, French Polynesia, and China, the nucleation process is intricate and requires expertly trained technicians.
The pearl industry, like others, was adversely affected by the COVID-19 pandemic. Many dealers noted a supply shortage of the main types of cultured pearls: South Sea, Tahitian, akoya, and freshwater. According to dealers, many pearl farms, especially Tahitian, use Chinese and Japanese technicians to perform the critical nucleation step. Due to travel restrictions and border closures during the pandemic, many experts were unable to travel to these locations, resulting in smaller harvests since 2020. In some farming areas, there were not enough employees on-site to keep the mollusks in good health, and thus the mortality rate was high. Assuming grafting returned to normal levels by 2022, a greater influx of supply is expected in 2024, given the typical 24-month growth periods. Some dealers added that strong demand for cultured pearls from Chinese and other Asian consumers is contributing to the current global shortage.

Figure 2. Left: Small round freshwater bead cultured (BC) pearls (top group of strands) and small round Japanese akoya BC pearls (bottom strands) appear very similar at first glance. Right: Upon closer inspection, the freshwater pearls more often show a rounded flat surface feature. Photos by Artitaya Homkrajae and Lisa Kennedy; courtesy of American Pearl Company Inc.
Small freshwater BC pearls from China (approximately 2–4 mm) were more widely available at the show than in past years, in near-round to round shapes and in various colors including white, pink, purple, and orange (figure 1). Freshwater cultured pearls of this particular size are typically NBC, normally oval (a potato-like shape), and can look similar to white saltwater Japanese akoya BC pearls of the same size. However, Gina Latendresse of American Pearl Company Inc. (Nashville, Tennessee) demonstrated that upon closer inspection, the freshwater pearls more often show a rounded flat surface feature on an otherwise spherical pearl, a feature usually too small to affect basic shape (figure 2). This feature is also occasionally observed in other types of freshwater cultured pearls.

Figure 3. Vietnamese akoya bead cultured pearls in various colors ranging from silver to light gray to light bluish gray. The pearls were said to be unprocessed and untreated. Photo by Lisa Kennedy; courtesy of Eliko Pearl Company.
Eliko Pearl Company (New York City) displayed numerous strands of Vietnamese akoya BC pearls with bodycolors ranging from silver to light gray and light bluish gray with exceptional orient (figure 3). These provide a greater selection of colors compared to traditional akoya BC pearls. Some white, light cream, and  cream pearls were also presented as unprocessed and untreated—steps normally used to improve appearance and alter color. However, many akoya BC pearls in the market have been processed to generate a classic white appearance. Vietnam has produced saltwater cultured pearls commercially since the 1990s and is expected to produce approximately 2,000 kg per annum (N. Sturman et al., “Vietnam: Shell nuclei, pearl hatcheries, and pearl farming,” Fall 2020 G&G, pp. 402–415), which is significantly smaller than Japan’s anticipated annual production of approximately 20 tons (roughly 18,000 kg) (T. Matsuyama et al., “Mass mortality of pearl oyster (Pinctada fucata (Gould)) in Japan in 2019 and 2020 is caused by an unidentified infectious agent,” PeerJ, Vol. 9, 2021, article no. 12180).

Figure 4. This set of ombré pearl strands, made up of round Tahitian pearls with silver and gold South Sea pearls ranging from 10 to 10.4 mm, is also known as shikisai, which means “colors of four seasons” in Japanese. Photo by Mimi Travis; courtesy of Yen’s Jewelry & Accessories Inc.

Figure 5. Mixed strand of 79 pearls ranging from 11.8 to 14.8 mm, consisting of pink Chinese freshwater, black Tahitian, golden Indonesian, and white Australian bead cultured pearls. Also pictured is an exceptionally large 20.4 mm South Sea bead cultured pearl, weighing 12 g. Photo by Robert Weldon; courtesy of Yoko London.
Eric Yen of Yen’s Jewelry & Accessories Inc. (San Francisco) and Alan Hakimian of Yoko London presented strands that combined multicolor pearls from different pearl types, offering variety and high fashion all at once (figures 4 and 5). Both pointed out that making mixed and graduated color strands is an efficient use of all the pearls produced from a harvest, just one example of economic sustainability in the pearl industry. Producing only perfectly matched color stands would lead to more waste.
Overall, pearl dealers are looking forward to the return of the gem, jewelry, and pearl shows in Hong Kong in 2023, as these are some of the largest shows for cultured pearls. Many have not been able to attend since 2019 due to lockdown restrictions in Hong Kong. Source: GIA @topic:5


Title: Iridescent Spondylus Pearl Abstract: Figure 1. This 6.97 ct bicolored white and pink Spondylus pearl shows prominent reflective blue coloration over the fine parallel flame structure when viewed in certain directions under a single white light source. Photo by Robert Weldon/GIA.

	The optical phenomenon of iridescence is frequently observed in gem materials, but it is uncommon to see iridescent colors in porcelaneous pearls. Such pearls are appreciated for their prominent eye-visible flame structures, such as those seen in some Queen conch and Melo pearls. Pearls from these gastropods, along with Spondylus species bivalves, are routinely submitted to GIA’s laboratory. A bluish reflective sheen is a common feature of the flames seen in Spondylus pearls (Fall 2014 Lab Notes, pp. 241–242; Winter 2015 Lab Notes, pp. 436–437).

	A 6.97 ct bicolored white and pink Spondylus pearl (figure 1) was recently examined at GIA’s Carlsbad laboratory. When a single white light was used to illuminate the pearl, a prominent reflective blue coloration over its fine parallel flame structure was visible on the white portions. This created a pseudochatoyant effect similar to other Spondylus pearls previously examined. What was particularly captivating about this pearl was that iridescent colors ranging from purplish to a dominant blue were seen on the fine, well-formed flame structure when a fiber-optic light was applied in certain directions (figure 2).

Figure 2. Under magnification and using fiber-optic illumination, iridescent colors ranging from purplish to dominant blue reflect from the fine, well-formed flame structure of this Spondylus pearl. Photomicrograph by Artitaya Homkrajae; field of view 2.34 mm.

	As with many gemstones and nacreous pearls, the spectral colors seen on the flame structure are the result of the interference effect of light reflecting off of structural features. In this case, the thickness of the aragonite lamellae permits white light to be diffracted into most of the visible light wavelengths, resulting in a colorful effect.

	The iridescence characteristics of this pearl have not been encountered to such a marked degree in any other porcelaneous pearl examined by GIA. Source: GIA @topic:5


Title: Large Natural Quahog Pearl Abstract: Figure 1. This northern quahog pearl exhibited a fine color and shape. Photo by Jian Xin (Jae) Liao.

A notable purple non-nacreous pearl (figure 1) recently submitted to GIA’s New York laboratory measured 13.69 × 11.80 mm and weighed 16.64 ct. It was immediately recognizable as an outstanding specimen due to its clean surface, which possessed an attractive sheen reminiscent of fine porcelain. It had good symmetry, featuring a near-round button shape with a perfect dome top and a rounded base, and a richly saturated and well-distributed mid-purple color.

Real-time microradiography revealed a tight internal structure, a common characteristic of certain natural non-nacreous/porcelaneous pearls. Raman spectroscopy using 514 nm laser excitation (figure 2) showed characteristic aragonite peaks at 702, 706, and 1086 cm–1, as well as 1130 and 1520 cm–1 peaks related to a mixture of polyenic (polyacetylenic) compounds, the natural pigments responsible for its purple color, as previously observed in similar pearls (Winter 2008 GNI, pp. 374–375). The characteristic natural purple color and non-nacreous porcelaneous appearance indicated a pearl from the bivalve mollusk Mercenaria mercenaria (belonging to the Veneridae family), also referred to as the “northern quahog.”

Figure 2. The quahog pearl’s Raman spectrum showed the typical aragonite peaks
seen in most pearls, together with 1130 and 1520 cm–1 peaks related to a natural
coloring compound.
Quahogs are native to the Atlantic shores of North America from Canada to Georgia, especially on the coast of the New England states, and can also be found along California’s Pacific coast. They can produce non-nacreous porcelain-like pearls, and their shells typically exhibit an uneven white and purple interior color (figure 3). Quahog pearls may occur in a variety of colors ranging from white to brown and from faint pinkish purple to dark purple. Like other natural pearls, quahog pearls are rarely spherical. Button shapes with flat bases are most often encountered.

Figure 3. This quahog shell from the eastern coast of the United States has a naturally attached pearl. Photo by Robert Weldon.
Natural northern quahog pearls are often submitted to GIA labs. Most are below 10 carats with a flat-based button shape, usually with a dark or light purple color, and tales of their accidental discovery while eating clams are not uncommon. This quahog pearl’s large size, clean surface, fabulous luster, near-round shape, and evenly distributed rich color combine to make it an exceptionally fine and rare example of its type. Source: GIA @topic:5


Title: “Sango Pearl” from Japan Abstract: Figure 1. Sango pearls (left and center) and a coral bead nucleus (right), each approximately 6 mm in diameter. Photo by Y. Katsurada.

A type of pink Japanese akoya cultured pearl, introduced about a decade ago and known as “Sango” pearl (figure 1), uses a pink coral nucleus and a Pinctada fucata mollusk. It is produced by Matsumoto Pearls, a Japanese pearl farming company based in Uwajima, Ehime Prefecture. Sango is the Japanese word for coral, and the species of pink coral used as the nucleus is likely a Corallium species, one of the precious corals harvested off the Pacific coast of Japan, especially around southern Kochi Prefecture (N. Iwasaki et al., “Biology of Japanese Corallium and Paracorallium,” Proceedings of the First International Workshop on Corallium Science, Management, and Trade, 2009, pp. 68–70). Matsumoto Pearls has successfully combined two beautiful organic gem materials to produce these attractive pink-colored pearls.

The coral nuclei in this study exhibited a pinkish orange color and measured 5.60–5.90 mm in diameter. Under microscopic examination, white layer-like structures and banding as well as polyp-related cavities have sometimes been observed. The nuclei also exhibit a weak whitish and stronger whitish fluorescence under short-wave and long-wave UV, respectively. The coral bead’s Raman spectrum (figure 2, top) shows strong pigment peaks at 1129 and 1517 cm–1 and calcite peaks (e.g., 280 and 713 cm–1), identifying them as Corallium species, as in S. Karampelas et al. (“Identification of the endangered pink-to-red Stylaster corals by Raman spectroscopy,” Spring 2009 G&G, pp. 48–52). The full-range photoluminescence spectra closely match that of natural pink coral with natural pigment-related peaks, similar to those in C.P. Smith et al. (“Pink-to-red coral: A guide to determining origin of color,” Spring 2007 G&G, pp. 4–15). Visible-range reflectance spectra (figure 2, middle) reveal peaks at 468, 482, 590, and 666 nm, like those observed in the spectra of natural coral by C.P. Smith et al. (2007). Ten partially drilled Sango pearls examined for this note were of a similar size (5.60–6.00 mm) as the coral beads used as nuclei. No color concentrations were noted down the drill holes or anywhere on their nacreous surfaces using a loupe or microscope. The nacre thickness measured between 120 and 400 microns (0.12–0.40 mm) under the microscope using a small table gauge. The different nacre thicknesses were also visible in real-time X-ray (RTX) images (figure 3). The pearls exhibited excellent luster, with almost no overtone and very weak orient, and showed a weak yellow to greenish yellow fluorescence under long-wave and short-wave UV radiation, respectively. These observations indicated that the 10 samples’ pink coloration was natural, though it remained to be seen whether the pink color originated from the pearls’ nacre or the underlying coral beads.

Figure 2. Top: Raman spectra of a coral bead (black trace) and a Sango cultured
pearl (pink trace) with pigment-related peaks at 1129 and 1517 cm–1. The bead’s
peaks are stronger at those wavelengths. Middle: Visible-NIR spectra of a coral
bead (black trace) and two Sango cultured pearls showing the different reflectance
values obtained. The dark pink trace represents thinner nacre (120 μm thick); the
light pink trace is from nacre that is 400 μm thick. Bottom: Plot of the relationship
between nacre thickness and the differential reflectance of Sango pearls at 482 nm
based on the average reflectance of the coral beads (differential reflectance =
RSango pearls – Rcoral beads).

Figure 3. RTX images of Sango cultured pearls showing clear demarcations between the larger coral bead nucleus and thinner nacre overgrowth. The pearl on the left has a thinner nacre than the one on the right.
Chemical analysis using an energy-dispersive X-ray fluorescence (EDXRF) spectrometer revealed manganese levels of 0 to 28 ppmw and strontium levels of 1077 to 1719 ppmw, indicating that the pearls formed in a saltwater environment. A useful observation was that pearl color seemed to be related to nacre thicknesses: Thin nacre overgrowth produced a more obvious pink tint, while thicker nacre resulted in a less saturated pink. Likewise, the Raman and visible-range reflectance spectra were also related to the nacre thickness. Raman spectra for pearls with thin nacre showed stronger pigment peaks at approximately 1129 and 1517 cm–1, similar in strength to those noted in the coral beads; only the aragonite-related peaks—and no pigment peaks—were noted in pearls with thicker nacre (see figure 2, top). The visible-range spectra of the pearls possessing thin nacre also matched the coral beads more closely, albeit with a lower reflectance (figure 2, middle), while pearls with thicker nacre had higher reflectance, as would be expected for lighter-colored pearls. By correlating the coral pigments with the maximum visible reflectance spectrum at 482 nm, the point of least reflectance (see figure 2, bottom), the relationship between nacre thickness and the visible spectra of the pearls could be gauged. The intensity at 482 nm indicates that the pink color of Sango pearls most likely originates from their coral nuclei.

While Sango pearls are not the first cultured pearls to use atypical bead nuclei in the form of other gem materials (see K. Scarratt et al., “Atypical ‘beading’ in the production of cultured pearls from Australian Pinctada maxima,” GIA Research News, 2017, https://www.gia.edu/gia-news-research/atypical-beading-production-cultured-pearls-australianpinctada-maxima), this is the first time the author has analyzed the detailed color origin of Sango pearls with Pinctada fucata mollusks as the host. The pearls are known to possess relatively thin nacre overgrowth, which has enabled the creation of the commercial type of akoya cultured pearl using a natural coral nucleus. GIA would classify Sango pearls as atypical bead-cultured pearls. Source: GIA @topic:5


Title: Cultured Pearl Market Update Abstract: Figure 1. Mastoloni described this fine 16.4–16.7 mm Tahitian cultured pearl with natural color and luster as his “new favorite pearl.” He added that top-quality examples like this are increasingly hard to find. Photo by Duncan Pay/GIA; courtesy of Mastoloni Pearls.

At the 2014 AGTA show, Fran Mastoloni (Mastoloni Pearls, New York City) provided a market summary from his own business perspective. He emphasized surging demand in the Chinese domestic market for all cultured pearl types, plus the need to introduce innovative styles and pearl combinations in contemporary jewelry. Since then, overall supply of fine cultured pearls of every type has become even more challenging.

This year, Mastoloni reported that Chinese demand for Philippine golden cultured pearls continues unabated, and the domestic market there is absorbing nearly all available production, effectively pricing them out of the North American market. Although never a high-turnover item in the U.S., any such pearls sold in the American market will likely come from suppliers’ existing inventory. And once sold, they will not be replaceable given current market prices. Mastoloni predicted an eventual downward correction, once the Asian market’s appetite for golden pearls is sated.

Supply of quality Tahitian cultured pearls (figure 1) is also becoming problematic. Mastoloni said the Tahitian government has ceased support of pearl farmers, with a resulting decline in colors, sizes, and overall product quality. Exceptional pearls are particularly scarce. He was very concerned about pearl production over the next 10 years. Prior to 2008, he said, Tahitian pearl farmers were very conscientious about quality. Today, in Mastoloni’s words, “Farmers are producing to turn over.”

[Editor’s note: On October 1, 2008, the Tahitian government abolished the pearl export tax, which had largely supported the GIE Perles de Tahiti industry association. This removed the funding for the promotion of Tahitian cultured pearls, leading to GIE Perles de Tahiti’s collapse in 2012. The 2008 global economic downturn drastically curtailed pearl sales and stressed many Tahitian pearl farmers (see A. Müller, “A brief analysis of the global seawater cultured pearl industry,” European Gemmological Symposium, Bern, Switzerland, June 5, 2009, pp. 7–10). Since the collapse of GIE Perles de Tahiti, producers have increasingly looked to China as a promising export market, which is also likely to affect availability for U.S. and European markets.]

Mastoloni noted that white South Sea cultured pearls remain the standard by which fine pearls are judged. Although fine quality is still difficult to find, supply is good. He showed us a spectacular Australian South Sea necklace composed of white to pink 15.5 to 19 mm-plus baroque pearls with excellent luster and unblemished surface (figure 2). Weighing in at an “extraordinary” 46.1 momme (172.88 grams), this necklace took more than two years to complete. There is always the temptation to keep improving a piece, to make it “bigger and better.” As an example, he showed us a large baroque specimen that measured 23.3 × 28.6 mm and weighed 4 momme (15 grams), with superb luster, that he would like to make the centerpiece of the necklace. Prices for baroque cultured pearls are stable with moderate demand, he noted, but sourcing high-quality goods is somewhat difficult.

Figure 2. Top-quality Australian South Sea baroque cultured pearls 15.5 × 19.0 mm and larger grace this spectacular necklace. Photo by Duncan Pay/GIA; courtesy of Mastoloni Pearls.
Mastoloni said fine akoya cultured pearls are also in high demand. Once again, he faces competition from Chinese buyers purchasing for their domestic market. According to Mastoloni, pearl farmers in China are no longer concentrating on smaller round pearls. They are not producing enough 5, 6, or 7 mm diameter goods in sufficient quality, in either akoya or freshwater types, to satisfy demand. The result is increased competition, with Chinese buyers competing at the source in Japan for akoya. This demand is driven by the emerging wealth of Chinese consumers. Their purchasing power and the sheer quantity of consumers in the Chinese domestic market is fueling unprecedented demand. They are looking for better quality, and fine Japanese akoya pearls meet that need.

Figure 3: Left: Long necklaces are in style. This “Wave” necklace features multicolored Tahitian cultured pearls ranging from 7 to over 14 mm. Right: This close-up of the necklace shows its repeating color and size patterns in a succession of “waves.” Photos by Duncan Pay/GIA; courtesy of Mastoloni Pearls
In terms of trends, Mastoloni noted that “long is in.” Double- and triple-length necklaces from 32 to more than 50 inches are very popular, he said. He has also noticed that basic necklaces are making a comeback, and more retailers are asking him to supply “regular” necklaces for their inventory. Mastoloni showed us a double-length necklace that made clever use of soft-colored round Tahitian cultured pearls in a variety of sizes. He called it the “Wave” necklace (figure 3). “Swells” graduating from 7 to over 14 mm form waves in repeating color patterns along the length of this necklace (approximately 36 inches), creating a layered look. The repeating size and color patterns lend a sense of movement and drama. Source: GIA @topic:5


Title: Cultured Pearl Update Abstract: Figure 1. The pearl market has seen a rise in popularity in pieces with unusual color (left) and size combinations (right). Photos by Kevin Schumacher.
We had the opportunity to speak with Fran Mastoloni (Mastoloni Pearls, New York) at the AGTA show and hear his thoughts on the current status of the cultured pearl market.

According to Mastoloni, pearls continue to do very well. His company had one of its best fourth quarters in recent history, and he believes that has much to do with the pearl cycle. He noted that pearls tend to be in fashion in seven-year periods. Mastoloni believes this is the second year of a seven-year trend. Last year pearls were making a resurgence, but instead of classic white pearls they were selling unique and fashionable pieces, such as the cocktail necklaces of white South Sea, gold Philippine, and silvery Tahitian pearls seen in figure 1, left. Mastoloni explained that customers are enjoying the organic shapes and colors of these different varieties and how versatile such necklaces and pieces can be. This trend has continued into 2018, but they are selling these unusual combinations to designers and major manufacturers rather than individual stores. These clients are incorporating Tahitian or keshi pearls or stations into necklaces, as well as Mastoloni’s colored pearl palette, with their own design elements. Mastoloni also noted a greater use of keshi pearls as stations, with one designer planning to use a bezel-set light sapphire between the stations to create something different, fun, and marketable.

Fran Mastoloni’s Cultured Pearl UpdateFran Mastoloni talks about the current state of the pearl market, and shows us some of his most popular necklaces.
Fine pearls continue to sell, though with a twist. Mastoloni’s top sellers include white South Sea, Indonesian, and Australian pearls in classic styles such as long necklaces, but with a more organic appearance. The price point is very important, Mastoloni said, because a number of customers self-purchase for work or to satisfy their own tastes. In fact, he has found that self-purchasing of pearls has become more popular than gift giving. Pearls are versatile and can be worn anywhere, he said, because they communicate that the wearer is confident but not ostentatious.

Mastoloni showed us two graduated Japanese akoya necklaces that appear to date from the 1970s or ’80s. The pearls measure 7.5 × 10.5 mm and are perfectly matched, with no imperfections and a nacre coating that is just not seen anymore; he has three other strands that are slightly smaller. These sizes are “almost unheard of” in akoyas and make for an unusual addition to a collection. He also showed his “cloud” necklace (figure 1, right), one of his most popular, created from Chinese tissue-nucleated pearls. Chinese pearls are sold by weight, and the cultivators are using larger nuclei to create larger pearls. Since pearls are no longer grown in the sizes used in this necklace, this material is unlikely to be found on the market despite its popularity. Source: GIA @topic:15


Title: Spiral Nacre in Natural Pearl Abstract: Concentric spiral nacre formations seen on a natural saltwater pearl. Photomicrograph by Britni LeCroy; field of view 2.34 mm.

Nacreous pearls are known to have platelet growth resembling fingerprints or topographic maps, but a less common appearance is nacre with a concentric spiral pattern. The feature is sometimes seen in small patches in unprocessed saltwater pearls. One recent example was exceptional as it showed spiral formations throughout its entire surface (see above). The pearl was determined to be a natural saltwater pearl from the Pinctada genus. Nacre is composed of aragonite crystals and conchiolin protein, with the crystals acting like bricks and the protein acting like mortar. The explanation for spiral patterns is complex and involves the development of screw dislocation defects during nacre formation as predicted by the Burton-Caberra-Frank theory (J.H.E. Cartwright et al., “Spiral and target patterns in bivalve nacre manifest a natural excitable medium from layer growth of a biological liquid crystal,” PNAS, Vol. 106, No. 26, 2009, pp. 10499–10504). Source: GIA @topic:5


Title: Dyed Non-Nacreous Pearls Abstract: Figure 1. These four non-nacreous pink and light pink pearls submitted for identification weighed (left to right) 1.30, 2.88, 4.41, and 5.88 ct. Photo by Lhapsin Nillapat.
Recently, 90 items purported to be pearls were submitted to GIA’s Bangkok laboratory for identification. While the majority were confirmed to be natural pearls, four samples warranted further study. Each of these four samples exhibited a non-nacreous surface, and on first impression they appeared to be conch pearls owing to their pink and light pink coloration. Their measurements ranged from 6.53 × 5.11 × 4.92 mm to 10.64 × 10.46 × 7.28 mm, and they weighed 1.30, 2.88, 4.41, and 5.88 ct, respectively (figure 1).

Figure 2. A: Red dye visible within surface-reaching features of the 1.30 ct pearl; field of view 3.60 mm. B: Red dye concentrated in and around surface-reaching features of the 2.88 ct pearl; field of view 2.88 mm. C: An underlying white area where the red dye did not cause discoloration of the 4.41 ct pearl. Flame structure is evident in the white area; field of view 7.20 mm. D: Clear flame structure with areas of pink dye concentrated in the surface features of the 5.88 ct pearl; field of view 7.20 mm. Photomicrographs by Kwanreun Lawanwong.
Observation through a 10× loupe and a microscope revealed that the samples were non-nacreous pearls. However, it was also readily apparent that the colors had been modified and were not natural. The 1.30 ct pearl exhibited the flame-like structure routinely observed in pearls such as conch, but the obvious red dye visible over the entire surface made it difficult to determine whether the flame structure was really present (figure 2A). The 2.88 ct pearl displayed a subtle flame structure, and some pink dye was visible on the surface and within many surface blemishes (figure 2B). Some surface areas of the 4.41 ct pearl showed the original bodycolor (figure 2C), but much of the surface showed the same dye features seen in the previous two pearls. Finally, the 5.88 ct pearl exhibited a nice flame pattern throughout, with some surface areas on the base and circumference modified by working (The Pearl Book, CIBJO Pearl Commission, 2020; N. Nilpetploy et al., “A study on improving the surface appearance of low-quality Pinctada maxima bead cultured pearls,” GIA Research News, March 24, 2021).
The color origin of this pearl was a little more challenging to identify because most areas were a lighter color, and as a result, the color modification evidence was harder to see with the unaided eye. However, magnification revealed pink dye concentrations within cracks on the base and in some surface-reaching structural features (figure 2D). Real-time microradiography (RTX) revealed a variety of structures within the pearls. The organic-rich and void features observed could be interpreted as characteristic of some non-bead cultured pearls. While they may be considered suspect, similar features have been observed in natural non-nacreous pearls (E. Fritsch and E.B. Misiorowski, “The history and gemology of Queen conch ‘pearls’,” Winter 1987 G&G, pp. 208–221; S. Singbamroong et al., “Observations on natural non-nacreous pearls reportedly from Tridacna (clam) species),” 34th International Gemmological Conference, Vilnius, Lithuania, 2015; Summer 2018 Lab Notes, pp. 211–212). To date, there have been no reports of any commercially produced non-nacreous cultured pearls in the market. Thus, based on surface observations and their internal structures, they were identified as treated-color natural non-nacreous pearls.

Figure 3. Photoluminescence spectra of the four pearls together with the spectrum of a pink conch pearl from GIA’s reference database. The spectra of the treated pearls differ from that of the conch pearl, which shows a series of very clear polyenic peaks. These peaks are characteristic of many naturally colored porcelaneous pearls.
Further examination under long-wave ultraviolet radiation showed a weak to moderate red reaction over the colored areas, while the white area on the 4.41 ct pearl and the lighter-colored areas on the 5.88 ct pearl exhibited bluish reactions of moderate to strong intensity. Ultraviolet-visible (UV-Vis) reflectance spectra revealed absorption features expected for pink pearls in the visible range, but the absorption patterns differed from those typical of naturally colored conch pearls. Raman spectra collected using a 514 nm laser revealed peaks (doublet) related to the vibration modes of aragonite at 702 and 705 cm–1. All of the pearls showed additional weak peaks at 485, 640, and 827 cm–1 and less-defined features between 1000 and 1700 cm–1. However, none were associated with the polyenic peaks observed in most naturally colored non-nacreous pearls (Summer 2017 Lab Notes, pp. 230–231; Summer 2018 Lab Notes, pp. 211–212). The photoluminescence spectra also differed from those expected for naturally colored pink conch pearls and lacked the obvious polyenic peaks routinely observed in such pearls (figure 3).
Surface observation using the loupe and microscope combined with the results obtained from advanced analyses on the colored surface areas led us to conclude that the colors of the four pearls had been modified. While this is not so surprising when it comes to nacreous pearls, it is, from the author’s experience, more unusual to encounter color-modified natural non-nacreous pearls. Since these samples appeared visually similar to conch pearls, we can speculate that the original white or lightly colored pearls were dyed pink to imitate those produced by the Queen conch mollusk (Lobatus gigas, formerly known as Strombus gigas). This would make sense based on consumer demand in the market. However, the exact reason for treating these particular samples is unknown. Source: GIA @topic:5


Title: 2020 World Pearl Congress Abstract: Figure 1. GIA consultant Nicholas Sturman presented on freshwater pearls during the conference. Photo by Lin Chen.

The World Pearl Congress was held November 13–15, 2020, in Shanxiahu Town, a division of the Chinese city of Zhuji. Known as “China’s pearl capital,” Shanxiahu Town is known for cultivating, processing, trading, and researching pearls, especially freshwater pearls. The town produces nearly 80% of China’s pearls and is currently home to more than 2,500 pearl companies. This event was organized by CIBJO, the Gems and Jewelry Trade Association of China, the Zhejiang Provincial Committee of China Council for the Promotion of International Trade, and the Shaoxing Municipal People’s Government.
The event consisted of a series of activities, presentations, and exhibitions focused on pearls. Despite the global pandemic, more than 400 attendees who live in China and represent a number of professions and industries attended this meeting in person, while several international and domestic speakers delivered a series of talks via prerecorded videos. Presentations included: “Freshwater Pearls from a Laboratory Perspective” (Nicholas Sturman, GIA consultant) (figure 1), “An Overview of the Global Pearl Industry” (Kenneth Scarratt, CIBJO Pearl Commission president), “Development of Quality and Detection of Pearls” (Taijin Lu, NGTC chief scientist), “The Importance of Design to the Pearl Industry” (Paloma Sanchez, independent designer), among many others. In addition, the World Freshwater Pearl Museum was also unveiled (figure 2), with exhibitions detailing the rich history of pearl culturing in China, pearl cultivating and processing techniques, and varieties of freshwater pearls and pearl jewelry.

Figure 2. The new World Freshwater Pearl Museum was recently opened in Zhuji, China. Photos by Lin Chen.
According to several sources at the meeting, the global pandemic caused little disruption to the production of freshwater cultured pearls, as the harvest usually takes place at the end of the year and the government’s fast control of the virus minimized the impact. However, the export of freshwater cultured pearls has been significantly affected, and dealers are trying to boost domestic sales with more emphasis on a strong online presence. Among different sales methods, livestreaming has become an ever more popular way to sell pearl jewelry in China (figure 3). From January to November 2020, online sales of pearls in Zhuji were valued at 11.85 billion yuan (US$1.8 billion), a year-over-year increase of 18.5%, according to Sina Finance.

Figure 3. Livestreaming has become one of the most popular ways for online selling of pearls in China, as shown in this Ruans store in Zhuji. Photo by Lin Chen. Source: GIA @topic:5


Title: Clam Chowder with a Side of Pearl Abstract: This white and purple pearl was found by restaurant staff while shucking clams for New England clam chowder. It formed in a northern quahog clam (sample shell shown). Photo: Sood Oil (Judy) Chia/GIA

Recently, GIA’s laboratory in New York had the opportunity to examine a fascinating find and hear about an even more fascinating story.

According to Bryan Gosman, co-owner of Gosman’s Fish Market in Montauk, Long Island, one of his staff was shucking clams in the kitchen while preparing to cook New England chowder when he discovered a pearl the size of a gumball.

“It didn’t look real,” said Gosman. “Usually [pearls are] the size of your pinky nail or something like that, but this looked like a plastic knob.”

He then reached out to Rebekah Harris – a co-owner of The Shipwreck Jewelry and Trading Company – to help him confirm the identity of the pearl. She assured him that the pearl was genuine and also the largest one she’d ever seen outside of a museum. She helped him submit the pearl to GIA in New York.

The quahog pearl was submitted to GIA’s New York laboratory for a GIA Pearl Identification Report. Photo: Sood Oil (Judy) Chia/GIA
GIA scientists confirmed that the pearl formed in a Mercenaria mercenaria (northern quahog) “clam.” It weighed 27.78 carats and measured 18.96 x 11.32 mm. To put that in perspective, many cultured pearls in jewelry stores range from 8-12 millimeters, meaning that this natural pearl is extraordinarily large. It is also a near perfect button shape, with an attractive white and purple color. Unlike many pearls valued for jewelry, it is non-nacreous, meaning its surface structure is different and has a more porcelaneous appearance.

Quahog ("koh-hawg") clams like the one that produced this pearl are found on the Eastern shore of North America, especially along the coast of the New England states, and can also be found along California’s Pacific coast. The pearls range in color from white and light gray to varied shades of purple, with purer colors being the most sought-after. Finding a quahog pearl is uncommon, not least because cleaning and shucking clams is often done mechanically, so most pearls are lost or destroyed in the process. The rare few pearls that make it into an unsuspecting patron’s food have been cooked, which can damage them. How fortunate that this pearl was discovered early and remained intact!

“What is it really worth? I don't know," Gosman said of the pearl. "It's not about the money – it's just kind of cool."

Gosman reported that he intends to raffle off the pearl to raise money for the Montauk Food Pantry.

The circumference of this button-shaped pearl is slightly larger than that of a dime. Photo: Sood Oil (Judy) Chia/GIA Source: GIA @topic:5


Title: Exceptional Natural Freshwater Pearl Abstract: Figure 1. This 16.23 mm, near-round 28.38 ct natural freshwater pearl was found along the banks of the Cumberland River in 2019. Photo by Emily Lane; courtesy of Gina Latendresse.

At the AGTA show, we visited Gina Latendresse at the American Pearl Company of Tennessee booth to find out about anything new in the pearl industry. We were excited to learn that an exceptional pearl, both in size and quality, was discovered last year in the Cumberland River (figure 1). The pearl was found by a fisherman along the bank of the river in a “Pistol Grip” (Tritogonia verrucosa) mussel (figure 2). This 28.38 ct white pearl with natural color measured 16.23 mm in diameter and was near round with good luster. This was the first pearl of such size and quality found in the Tennessee region since the 1970s. The pearl is so unusual that Ms. Latendresse described it as either a collector specimen or suitable for museum display.

Figure 2. The natural pearl from figure 1 shown in its shell (left), and the “Pistol Grip” shell exterior (right). Photos by Emily Lane; courtesy of Gina Latendresse.
For context, the eastern portion of the United States was a source of many natural freshwater pearls to native Americans as evidenced by John Smith’s 1608 writings noting the “many chains of great pearls about his [Chief Powhatan of the Powhatan Confederacy near present day Richmond, Virginia, also the father of Pocahontas] neck” (P.L. Barbour, Ed., The Complete Works of John Smith (1580–1631), Vol. 1, University of North Carolina Press, Chapel Hill, 1983, p. 53). Two and a half centuries later, a pearl rush started with the discovery of pearls of notable size and quality by fishermen in New Jersey, which resulted in people searching streams and rivers throughout the country. In 1857, David Howell found a near-round 100 ct pearl in a fried mussel he fished from Notch Brook in New Jersey (which unfortunately had its luster destroyed by the frying process). Shortly thereafter, Jacob Quackenbush discovered a 23.34 ct pink baroque pearl of fine luster, later named the “Queen Pearl,” that he sold to Charles Tiffany for $1,500. Good-quality pearls were found in the Cumberland, Tennessee, and Clinch Rivers in the state of Tennessee for many years thereafter (G.F. Kunz and C.H. Stevenson, The Book of the Pearl: The History, Art, Science, and Industry of the Queen of Gems, The Century Co., New York, 1908).
The recent discovery of such an extraordinary pearl proves that it is prudent to check the inside of mollusks known to produce pearls before consuming them! Source: GIA @topic:5


Title: Pearl History and Lore Abstract: A baroque pearl forms the body of a Triton in this jewel.  © Victoria and Albert Museum, London.

                      People have coveted natural pearls as symbols of wealth and status for thousands of years. A Chinese historian recorded the oldest written mention of natural pearls in 2206 BC. As the centuries progressed toward modern times, desire for natural pearls remained strong. Members of royal families as well as wealthy citizens in Asia, Europe, and elsewhere treasured natural pearls and passed them from generation to generation.

From those ancient times until the discovery of the New World in 1492, some of the outstanding sources of natural pearls were the Persian Gulf, the waters of Ceylon (now Sri Lanka), Chinese rivers and lakes, and the rivers of Europe.

During Christopher Columbus’s third (1498) and fourth (1502) voyages to the New World, he repeatedly encountered native people adorned with natural pearls. His discovery of natural pearl sources in the waters of present-day Venezuela and Panama intensified demand in Europe. However, within a hundred years, these natural pearl sources had declined due to overfishing, pearl culturing, plastic buttons, and oil drilling.

The first steps toward pearl culturing occurred hundreds of years ago in China, and Japanese pioneers successfully produced whole cultured pearls around the beginning of the twentieth century. These became commercially important in the 1920s (about the same time natural pearl production began to decline). From the 1930s through the 1980s, pearl culturing diversified and spread to various countries around the world.

Pearls are treasures from the Earth’s ponds, lakes, seas, and oceans, and they’ve always embodied the mystery, power, and life-sustaining nature of water.

The spherical shape of some pearls led many cultures to associate this gem with the moon. In ancient China, pearls were believed to guarantee protection from fire and fire-breathing dragons. In Europe, they symbolized modesty, chastity, and purity. Source: GIA @topic:5


Title: Pearl Quality Factors Abstract: This collection includes a palette of beautiful cultured pearls. Besides round golden white loose cultured pearls, there’s a strand of well-matched round whites and a strand of oval pastel colors.

                      The qualities that determine the overall value of a natural or cultured pearl or a piece of pearl jewelry are size, shape, color, luster, surface quality, nacre quality, and—for  jewelry with two or more pearls—matching.

Size: When other value factors are equal, larger pearls are rarer and more valuable than smaller pearls of the same type.

	The mollusk that produces South Sea cultured pearls is larger than the mollusk that
	produces Japanese saltwater cultured pearls. This leads to greater potential for larger
	sizes. - Gift of Bob & Maria Pratsch

	Cultured pearls come in a variety of sizes and South Sea cultured pearls are coveted for their large size. - Courtesy Paspaley
Shape: Round is the most difficult shape to culture, making it the rarest cultured pearl shape and—if all other factors are equal—also generally the most valuable. There are exceptions, though. Well-formed pear, oval, or baroque (irregularly shaped) cultured pearls are also prized by pearl lovers.

Different pearl types are held to different standards when classifying shape. Japanese saltwater cultured pearls are held to the strictest standards for shape. From top to bottom these strands are classified for shape as round, near-round, semi-baroque, and baroque.
Color: Natural and cultured pearls occur in a broad range of hues. There are warm hues like yellow, orange, and pink, and cool hues like blue, green, and violet. Pearls have a wide range of tone from light to dark. Pearl colors tend to be muted, with a soft, subtle quality.

	These Japanese saltwater cultured pearls display the white color most consumers associate with pearls. - Courtesy Paljoue International Inc.

	Cultured pearls can come in a variety of amazing colors. These Tahitian saltwater cultured pearls have a color intensity that’s almost like neon lights. - Courtesy Frank Mastoloni & Sons, Inc.
Pearl color can have three components. Bodycolor is the pearl’s dominant overall color. Overtone is one or more translucent colors that lie over a pearl’s bodycolor. And orient is a shimmer of iridescent rainbow colors on or just below a pearl’s surface. All pearls display bodycolor, but only some show overtone, orient, or both.

	These natural pearls from French Polynesia have a dark gray to black bodycolor. The middle pearl shows pink and green orient, while the overtone of the pearl on the left is mostly green.
The law of supply and demand determines the value of certain pearl colors at any given time. If supplies of high-quality pearls displaying a preferred color are low, their prices can rise to unusually high levels. Other complex factors, like fashion trends and cultural traditions, can influence color preferences.

Luster: Of the seven pearl value factors, luster might be the most important. Luster is what gives a natural or cultured pearl its unique beauty.

		Excellent – Reflections appear bright and sharp

		Very Good – Reflections appear bright and near sharp

		Good – Reflections are bright but not sharp, and slightly hazy around the edges

		Fair – Reflections are weak and blurred

		Poor – Reflections are dim and diffused

Within a pearl type, when other value factors are equal, the higher the luster, the more valuable the pearl.

	From top to bottom, these Japanese saltwater cultured pearls show excellent, very good, good, fair, and poor luster. The differences in the sharpness of the reflections between each adjacent strand are subtle but still noticeable.

	South Sea saltwater cultured pearls often have a beautiful satiny luster. - Courtesy King Plutarco, Inc
Surface quality: Like colored stones, most pearls never achieve perfection. Some might show abrasions that look like a series of scratches on the surface, or a flattened section that doesn’t affect its basic shape, or an irregular ridge that looks like a crease or wrinkle.

If surface characteristics are numerous or severe, they can affect the durability of the pearl and severely depress its value. Surface characteristics have less effect on the pearl’s beauty and value if they are few in number, or if they are minor enough to be hidden by a drill-hole or mounting.

Nacre quality: Luster and nacre quality are closely related. If the nucleus is visible under the nacre, or if the pearl has a dull, chalky appearance, you can assume that the nacre is thin. This affects the luster as well as the durability of the pearl.

	Good nacre quality often results in attractive luster, like the luster of these beautiful
	multicolored Tahitian cultured pearls. - Courtesy Armand Ascher Pearls, NY
Matching: Jewelry designers sometimes deliberately mix colors, shapes, and sizes for unique effects, but for most pearl strands, earrings, or other multiple-pearl jewelry, the pearls should match in all the quality factors.

	The white South Sea cultured pearl strand is well matched for all value factors. Even
	with its assorted hues, the multicolored strand is also considered well matched.
	- Courtesy Armand Ascher Pearls, NY Source: GIA @topic:5