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.

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

WATCH INDUSTRY GEMSTONES

GGTL Laboratories Switzerland provides grading and testing reports specifically tailored to the needs of the watch industry. We analyse and certify the gemstones used in high-end timepieces, including diamonds, and coloured stones, ensuring their authenticity, natural origin, and treatment status. Our reports are designed to meet the strict quality and transparency requirements of Swiss watchmakers and their clients, in compliance with the highest international gemmological standards.