Being the only gemmological laboratory to propose such service, GGTL Laboratories Switzerland offers the watch industry the cleaning and sorting of colourless melee diamonds and small calibrated gems after a chemical unmounting process. Not only will the stones be cleaned, but they will also be identified, controlled, sorted by sizes and full reports will be issued.

With more than 20 years of experience and a chemical laboratory dedicated to it, GGTL Laboratories Switzerland offers a specialized service in the cleaning and oiling of emeralds, unique in Europe. Whether the stones have been filled with oil or epoxy resin, our experts clean and re-oil, if desired. If your aim is to obtain a no clarity enhancement grade, we can help you as we also propose a deep cleaning that removes any quantifiable trace of filler.

GGTL Laboratories Switzerland is specialized in the identification of corals and their species. We are permanently carrying out scientific research on corals in order to increase our understanding of the material and its identification so our reports are in compliance with the CITES legislation.

In partnership with Mark Cullinan of Cullinan Diamonds, GGTL Laboratories Liechtenstein has developed the first real fingerprint diamond report: the Cullinan Diamond Report.
As the name “Cullinan” is associated with some of the world’s most spectacular diamonds, the Cullinan Report is a very special document. It represents a true fingerprint report of a diamond, hence a document that truly characterizes a diamond way beyond a regular diamond report.
Thanks to the extensive data kept at the laboratory, a diamond with a GGTL Cullinan report can be identified by the GGTL Liechtenstein laboratory at any time, even if it has been recut – within reasonable limits.

Cullinan colourless diamond report

Cullinan coloured diamond report