Over the years, GIA has encountered several cases of fraudulent GIA inscriptions, typically appearing as attempts to masquerade stones as natural diamonds. Such instances have involved diamond simulants (Fall 2022 Lab Notes, pp. 360–361), laboratory-grown diamonds (Summer 2021 Lab Notes, pp. 150–152; Summer 2025 Lab Notes, pp. 176–177), and treated diamonds (Fall 2021 Lab Notes, pp. 258–259; Summer 2025 Lab Notes, pp. 176–177).
Recently, the Mumbai laboratory examined a diamond with an inscription matching a prior GIA report for a 1.80 ct H-color diamond with VVS1 clarity and an Excellent cut grade. These characteristics were consistent with the original submission. The standard spectra collected for all diamonds submitted for grading reports, such as infrared absorption, also appeared to match. Despite these similarities and confirmation of the diamond’s natural origin, the weight was slightly greater than previously recorded (1.80058 ct versus 1.80776 ct), the cutting dimensions were marginally different, and the clarity characteristic plots did not match.
Importantly, the inscription on the recently submitted diamond did not pass comparison using GIA’s Match iD, a device that compares a diamond’s inscription with the corresponding grading report image stored in the GIA database. The comparison examines a wide variety of parameters between the inscriptions including the font, placement, spacing, and alignment with the background girdle faceting. Although the two inscriptions appeared quite similar (see above), particularly in the alignment with the girdle faceting, Match iD correctly indicated that these two inscriptions did not match.
The similarity in weight, spectra, color, clarity, and cut grades suggested a deliberate effort to select a diamond closely resembling the original reported stone. Although the inscription had similar positioning relative to the girdle facets, the fraudulent inscription was successfully identified. The most obvious misalignment shown in the two images is the position of the “A” with respect to the underlying facet. As the diamond with the fraudulent inscription was also natural, the motivation for this extensive effort is unclear. Such cases may represent an emerging form of natural diamond misrepresentation that warrants continued vigilance and monitoring.
This submission demonstrates that sophisticated attempts to replicate a GIA inscription can be detected through detailed inscription image analysis. It also highlights the effectiveness of MatchID in identifying counterfeit inscriptions, even when applied to a diamond that closely matches the characteristics of the original reported stone. When GIA receives a stone with a counterfeit inscription, a new report is issued and the fraudulent inscription is overwritten.
Jemini Sawant is a senior analytics technician, and Priyanka Yogesh Kadam is a supervisor of analytics, at GIA in Mumbai. Sally Eaton-Magaña is senior manager of diamond identification at GIA in Carlsbad, California.
Over the years, GIA has encountered several cases of fraudulent GIA inscriptions, typically appearing as attempts to masquerade stones as natural diamonds. Such instances have involved diamond simulants (Fall 2022 Lab Notes, pp. 360–361), laboratory-grown diamonds (Summer 2021 Lab Notes, pp. 150–152; Summer 2025 Lab Notes, pp. 176–177), and treated diamonds (Fall 2021 Lab Notes, pp. 258–259; Summer 2025 Lab Notes, pp. 176–177).
Recently, the Mumbai laboratory examined a diamond with an inscription matching a prior GIA report for a 1.80 ct H-color diamond with VVS1 clarity and an Excellent cut grade. These characteristics were consistent with the original submission. The standard spectra collected for all diamonds submitted for grading reports, such as infrared absorption, also appeared to match. Despite these similarities and confirmation of the diamond’s natural origin, the weight was slightly greater than previously recorded (1.80058 ct versus 1.80776 ct), the cutting dimensions were marginally different, and the clarity characteristic plots did not match.
Importantly, the inscription on the recently submitted diamond did not pass comparison using GIA’s Match iD, a device that compares a diamond’s inscription with the corresponding grading report image stored in the GIA database. The comparison examines a wide variety of parameters between the inscriptions including the font, placement, spacing, and alignment with the background girdle faceting. Although the two inscriptions appeared quite similar (see above), particularly in the alignment with the girdle faceting, Match iD correctly indicated that these two inscriptions did not match.
The similarity in weight, spectra, color, clarity, and cut grades suggested a deliberate effort to select a diamond closely resembling the original reported stone. Although the inscription had similar positioning relative to the girdle facets, the fraudulent inscription was successfully identified. The most obvious misalignment shown in the two images is the position of the “A” with respect to the underlying facet. As the diamond with the fraudulent inscription was also natural, the motivation for this extensive effort is unclear. Such cases may represent an emerging form of natural diamond misrepresentation that warrants continued vigilance and monitoring.
This submission demonstrates that sophisticated attempts to replicate a GIA inscription can be detected through detailed inscription image analysis. It also highlights the effectiveness of MatchID in identifying counterfeit inscriptions, even when applied to a diamond that closely matches the characteristics of the original reported stone. When GIA receives a stone with a counterfeit inscription, a new report is issued and the fraudulent inscription is overwritten.
Jemini Sawant is a senior analytics technician, and Priyanka Yogesh Kadam is a supervisor of analytics, at GIA in Mumbai. Sally Eaton-Magaña is senior manager of diamond identification at GIA in Carlsbad, California.
