Approximately 500 colourless to near colourless diamonds submitted primarily to GIA laboratory in Israel potentially were subjected to an undisclosed temporary treatment, says GIA alert.

GIA believes that the treatment is a process that temporarily masks the inherent colour of the diamond and can lead to a higher grade. The colour difference can be as much as three grades. GIA has not yet identified the treatment process, but this is being actively researched. According to GIA, at this time, the diamonds treated in this way have been submitted by just a few clients.

GIA has terminated submissions from the clients who have submitted these diamonds to GIA and have notified the appropriate trade bodies.

Report numbers with this suspected treatment are listed on GIA website and it has asked anyone who has purchased or holds these diamonds to please re-submit them to any GIA location for review. GIA will expedite the service, and no fee will be assessed.