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. Pioneer 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. Our experienced gemmologists carry scientific research in various aspects of gemmology both at the laboratories and through fieldtrips.

The founders

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

Dr Thomas Hainschwang

Dr Thomas Hainschwang’s main specialisations are diamonds and coloured 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 many years.

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 long experience in the identification of treatments and countries of origin and is a senior lecturer for the University Diploma in Gemmology (DUG) at the University of Nantes. 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 of 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 and researchers that are ready to help you with their expertise to shed light on all the secrets of your gems.


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