Lab Notes Gems & Gemology, Summer 2022, Vol. 58, No. 2

RFID Device Embedded in South Sea Bead Cultured Pearl Necklaces

South Sea bead cultured pearl necklace with an embedded electronic component.
Figure 1. A: Necklace of South Sea bead cultured pearls, 14.80–15.90 mm in diameter. Photo by Nuttapol Kitdee. B and C: Real-time microradiography (RTX) revealed one bead cultured pearl in the necklace containing an RFID device showing an obvious demarcation of typical shell bead nuclei. The embedded electronic component is visible as a white opaque stepped square feature. D: When aligned at right angles to the previous direction, the electronic component is harder to see but can be observed within a long, sharp laminated plane separating the two parts of the shell bead nucleus.

New technologies are increasingly being applied to cultured pearls, and it is exciting to witness developments in pearl traceability. GIA’s Bangkok laboratory recently received two South Sea bead cultured pearl necklaces, each consisting of 29 pearls ranging from 14.80 to 15.90 mm in diameter (strand A, figure 1A) and 14.40 × 14.20 mm to 16.20 mm in diameter (strand B, figure 2A). General observation under a binocular microscope revealed clear aragonite platelets characteristic of nacreous pearls, with no indications of treatment.

RTX imaging reveals RFID devices embedded in five bead cultured South Sea pearls.
Figure 2. A: Necklace of South Sea bead cultured pearls, 14.40 × 14.20 mm to 16.20 mm in diameter. Photo by Nuttapol Kitdee. B–D: RTX analysis revealed five bead cultured pearls containing an off-center RFID device within the shell bead nucleus.

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

RTX imaging reveals embedded RFID device in one pearl compared with bead cultured pearls with known RFID devices from GIA’s reference collection.
Figure 3. A: Necklace of South Sea bead cultured pearls, 10.04–12.21 mm in diameter. Photo by Tony Leung. B: RTX analysis of one of the pearls in the necklace revealed an RFID device. C: The internal structure was compared with two known bead cultured pearls containing RFID devices from GIA Hong Kong’s reference collection, and they proved to be identical. D: RTX clearly showed the outline of the square RFID device, as well as the sawn plane and small recess where the RFID device had been placed.

GIA’s Hong Kong lab has also begun seeing similar features in recent submissions (figure 3, A–B). The team compared the RTX data with some known bead cultured pearls containing an RFID device (figure 3, C–D) and confirmed that they were identical. The previous studies mentioned earlier describing RFID devices in bead cultured pearls have shown that these nuclei are produced by a patented pearl technology invented by Fukui Shell Nucleus Factory, which also supplies laminated beads to certain pearl farms. This explains the link between the laminating technique and its application in the production of RFID shell beads.

The use of RFID shell beads is known to assist in the storage of certain data such as a pearl farm’s location, mollusk data, and harvest date. However, a specific RFID reader is required to retrieve the data, so we were unable to obtain the information stored within these particular devices. Since the RFID devices do not influence their external appearance, the pearls containing a shell bead nucleus with such components are still identified as bead cultured pearls. Because the RFID device could increase the weight and have a misleading effect if undetected, a special comment is routinely included on GIA pearl identification reports as a means of disclosure. While pearl tracing technology has not been extensively adopted by the cultured pearl industry, the increasing number of electronic devices in shell bead nuclei submitted to the laboratory is noteworthy. GIA will continue to monitor and provide updates to the pearl trade and consumers.

Nanthaporn Nilpetploy is a senior staff gemologist at GIA in Bangkok. Ying Wai Au is a staff gemologist at GIA in Hong Kong.