About us

Rutiles in a ruby from Mogok

About us

Born from the merger of two already renowned laboratories in 2011 – GemTechLab founded by Franck Notari in 1996 (today GGTL Laboratories Switzerland) and Gemlab (Liechtenstein) founded by Dr Thomas Hainschwang also in 1996 (today GGTL Laboratories Liechtenstein) – GGTL Laboratories is an independent gemmological laboratory that combines cutting-edge technology and expertise to serve the gem trade and the scientific research. The laboratories based in Geneva and Balzers offer gem, diamond, and pearl testing reports as well as diamond grading reports. First pioneers in the melee parcels testing and grading for the watch industry more than twenty years ago, we also develop innovative scientific instruments specially built to improve gem testing. Moreover, our experienced gemmologists carry scientific research in various aspects of gemmology both at the laboratories and through fieldtrips.

As an independent laboratory with values, all our operating costs are exclusively covered through revenues gained from our services. For obvious reasons and to avoid any conflict of interest, we do not accept donations nor do we ask for financial backing from our customers. Likewise, and for the application of the same deontology, we do not take part in any transaction related to the gems we certify.

The founders

Our co-founders, Dr Thomas Hainschwang and Franck Notari, are both experienced and well respected multi-disciplinary gemmologists whose specialisations cover every the fields of gemmology.

Dr Thomas Hainschwang

Dr Thomas Hainschwang’s main specialisations are coloured and colourless diamonds - topics on which he has written his PhD (Type Ib diamonds) and his DUG (brown diamonds) at the University of Nantes and published numerous scientific articles. He’s been continuously working on advanced research project on coloured diamond for decades.

Research gage Dr Thomas Hainschwang View research gate profil

Franck Notari 

Franck Notari’s main specialisations are coloured gemstones, especially sapphire, ruby, and emerald : he has a great experience in the identification of gem treatments and geographical origins. He is a senior lecturer at the university of Nantes for the University Diploma in Gemmology (DUG) . Moreover, Franck Notari conducts several geological and gemmological researches in Mogok, a place he has been visiting regularly for several years. He is also head of scientific research, gemmological studies and testing at the Asian Institute of Gemological Sciences (AIGS) in Bangkok.

Research gage Dr Thomas Hainschwang  View research gate profil


The expert team of GGTL Laboratories includes gemmologists, diamond graders, geologists, physicists, and researchers that are ready to help you with their expertise and shed light on all the secrets of your gems.








Gemmologie & Francophonie


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