GRS Alert: Warming of Mozambique rubies that have previously been certified as unheated by GRS
We would like to inform our customers that rubies found to be unheated when tested by GRS are sometimes heated after certification and presented as natural unheated rubies to the market without re-certifying with GRS. This very low temperature warming does not require re-polishing of the stone and therefore no weight loss and no dimension changes are present.
As stated on our reports, the finding on the reports are only valid at the date they are made. Our customers are urged to insist on re-checks of the stone by GRS and postpone any payment transactions until we confirm our previous findings. Stones can be submitted in Bangkok, Switzerland, Sri Lanka or Hong Kong for re-checks.
We protest against this potential practice in the trade that has been brought to our attention and assure our customers that every tested ruby has a complete digital data set that will enable us to document post certification alterations in any gemstone submitted to GRS.
We are confident that this alert will deter those who like to profit from this practice.
Dr. A. Peretti
© 2021, GRS GemResearch Swisslab AG