Our Team


The Gubelin Gem Lab team consists of highly qualified and experienced specialists from seven different countries; between them they speak nine different languages – not forgetting “gemmology”, one of the languages they all have in common! Each team member is trained specifically in his or her field of work, such as gemmology, the operation of analytical instruments – even gemstone photography. Every gemmologist has a degree in an Earth Science (Geology, Mineralogy, Crystallography, Geography and so forth) complemented by a degree in Gemmology. On joining the Gubelin Gem Lab team, our gemmologists complete an intensive two to three years’ internal training programme before reaching the level of expertise that enables them to append their signatures to a Gubelin report. We are proud of our expertise and our skills which, complemented with each individual’s unique personality, contribute to the strong core of our company.


Dr. Daniel Nyfeler, Managing Director
Daniel spent the fieldwork studies portion of his Master’s thesis investigating the geology of the granulites in the Limpopo belt in Southern Africa. Following that, he worked on a joint research project on superconductors at the IBM Research Lab in Rüschlikon, Zurich, together with Georg J. Bednorz (Nobel Prize in Physics, 1987). Back at the University of Berne, he completed his PhD in Mineralogical Crystallography under Professor Thomas Armbruster, looking at steric and electronic stress situations in mineral structures and their influence on reactivity and atomic ordering. After several years spent at an international management consultancy, he returned to the sciences and joined the Gubelin Gem Lab in summer 2003.

Marc Leuenberger, Team Leader
With a background in the tourism and hospitality industry, Marc has been familiarized with the most sophisticated client needs early on. During his Bachelor's and Master's studies, he had the opportunity to both travel and study around the globe and thereby experiencing the diversity and peculiarities of the world's cultures at first hand. In April 2011, Marc graduated with a Master of Science in International Management. Combining his background in business research and management with his profound interest in the luxury goods industry, Marc joined the Gubelin Gem Lab as a Management Trainee in August 2011, assisting the Managing Director in various smaller and larger projects.


Sonia Cherchi, Head of Client Services
In her function as Head of Client Services, Sonia is in touch with our clients like no one else. She listens to their needs, supervises the planning and scheduling of the work in the laboratory and ensures the timely completion of services on the exclusive gems and jewellery our clients have entrusted us with. Her background and experience prepared her for this demanding position. She studied Earth Sciences at the University of Zurich, conducted her fieldwork in Yemen and graduated with an MSc in Geography. On leaving university, she honed her client service skills in the airline, art and tourism sectors. She joined the Gübelin Gem Lab team in 2004 after completing her gemmological training and gaining an FGA at the British Gemmological Association.


Dr. Lore Kiefert, Chief Gemmologist
Lore started studying Mineralogy in Heidelberg, Germany, in 1981 whereupon she completed her Master’s thesis on the origin of sapphires. She then moved to Australia for further scientific research and earned her PhD in 1996. Leaving Australia for Switzerland in 1994, she joined the SSEF Swiss Gemmological Institute as Deputy Director and went on to become Director of the Coloured Stones Department. During her time at the SSEF, she completed her FGA Diploma in 1996. Later, in 2005, Lore became Laboratory Director at the AGTA in New York until she decided to return to Europe to join the Gubelin Gem Lab as Chief Gemmologist in October 2009. Lore has written numerous articles in gemmological and scientific journals, as well as chapters in textbooks. She regularly delivers gemmological lectures at conferences and is also on the editorial review board of Gems & Gemology.


Susy Gubelin
Susy’s signature in Gubelin Gem Lab reports is proof that the Gubelin Lab is indeed a family business. Susy has been with the laboratory more than 25 years and has witnessed numerous developments and trends in the gemstone industry. She has vast expertise in all types of gemstones, and has had the privilege of analysing considerable numbers of the rarest and most famous gemstones over the years. Amongst many other exclusive items, she has tested a high double-digit number of diamonds above 100 carats, many of those IF and/or D colour. However, her favourite topic in gemmology is pearls, and she has had the opportunity of analysing many famous and exceptional examples, many of them of historic importance such as La Régente and the Hutton Pearls. 


Dr. Anna-Kathrin Malsy
Anna has been a mineral collector since her childhood and spent many holidays in Austria’s Habach Valley searching for emeralds. As her parents cut gemstones for pleasure, she became familiar with their fascination. As a consequence, the obvious decision was to study Earth Sciences. She completed her Master’s thesis at the University of Berne looking into the crystal structure and chemistry of double-ring silicates. Anna then studied Gemmology at the German Institute of Gemmology and joined the Gubelin Gem Lab in 2005. She was responsible for preparing and customising the LA-ICP-MS system for the use in the laboratory. From 2009 to 2012, Anna wrote her PhD thesis on spinels and alexandrites in cooperation with the University of Berne under the supervision of Professor Thomas Armbruster.


Pierre Hardy
Having a passion for minerals, Pierre moved from France to Australia and studied Geology at the Curtin University of Technology in Perth. On completing his thesis, he worked as a mining and exploration geologist for various mining companies, among them Argyle Diamonds, Rio Tinto and BHP, during which time he gained valuable experience in the mining industry. In our team, which he joined in 2008, Pierre is in charge of the diamond grading and analysis, both for commercial and fancy colours. He diligently pursues trends in the area of diamond treatments and synthetics.


Alessandra Spingardi
At the beginning of her academic training at the University of Pavia, Italy, Alessandra focused on historic ceramics and graduated with a Bachelors degree in archaeometry, applying geological techniques and methodologies to archaeology. Later, she moved to gemmology, writing her Master thesis on charge-transfer and colour-centre in thermally treated gemstones. Further research addressed the treatment of cordierite and quartz. In virtue of her accumulated knowledge on gemstones, Alessandra decided to further concentrate on this subject and opted for the gemmological training at the Gemological Institute of America (GIA). She joined the Gubelin Gem Lab in 2008, focusing on coloured gemstones and their origin determination.


Dr. Stefanos Karampelas, Scientific Researcher
Stefanos studied Geology and Mineralogy at the Aristotle University of Thessaloniki in Greece working on garnets and tourmalines during his diploma. He then relocated to the University of Nantes in France to complete his master’s in Geosciences, where he focused on the differentiation of natural from synthetic amethyst. His PhD studies in the colour of pearls and its treatments were undertaken in collaboration with the two aforementioned universities under the guidance of Professor Emmanuel Fritsch. 2007 saw Stefanos earn his advanced gemmological diploma (DUG) from the University of Nantes, working on diamond infrared spectroscopy. He has authored and co-authored numerous articles in scientific journals and he is frequently delivering lectures to scientific conferences and gemmological meetings. Since 2007 he has represented Greece in the International Mineralogical Association’s (IMA) Commission of Gem Materials. 


Beryl Huber
Named after a precious stone, Beryl was born into a family of watchmakers, goldsmiths and gemmologists in 1988. After finishing school, completing leisure and tourism vocational training and spending time in Canada, she became increasingly interested in making her personal passion her day-to-day job. This led her to Carlsbad where she completed her gemmological training at the GIA. She returned to Europe and applied for an internship at the Gubelin Group. Here she has worked in a variety of positions including sales, the goldsmiths’ workshop, the precious stones laboratory and finally as an analyst in a development project in the laboratory. She now works for the Gubelin Gem Lab as a dedicated and enthusiastic gemmologist. Beryl is the first employee to have analysed several thousand stones from the famous Gübelin Reference Collection under the microscope.

Dr. Wenxing Xu
Wenxing graduated with Bachelor's degree in gemmology and completed her FGA-Diploma in geosciences at the University of China (Wuhan). This is also the origin of her interest in gemstones and material sciences. In spring 2004 she moved to Germany and joined the group of Prof. Dr. Hofmeister at the Gemstone Research Institute of the University of Mainz where she was further studying mineralogy. She worked on various types of gemstones and other inorganic materials, applying spectroscopic, chemical and statistical methods. Her master`s thesis focused on freshwater cultured pearls, and her PhD thesis examined the origin determination of pottery extending her knowledge in the area of archeometrics. In 2014 she joined the Gübelin Gem Lab as a gemmologist.

Annette Widemann

Annette comes to Gubelin with a wealth of experiences from a variety of facets in the gemstone and jewellery industry. After completing her training in retail management, she worked in sales and became a retail trainer at Wempe. Her interest in precious stones led her to obtain gemmological training at the GIA in New York.  Her 18 years of experience working as a gemmologist with several major gemmological laboratories in New York and at Kaplan’s Auctions in Stockholm, make Annette an important asset to the Gubelin Gem Lab.


Klemens Link, Geochemistry Specialist

Klemens studied geology in Giessen (Germany) and completed his master thesis on the petrogenesis of mica schists in Southern France. Already as an undergraduate he attended to analytical, geochemical courses throughout Europe. From 2006 to 2013 he worked as petrologist and research scientist in the Earth Science Research Centre at the University in Mainz. During this time he intensified his experience in laser ablation inductively coupled plasma mass spectroscopy (LA-ICPMS). He was responsible for zircon geochronology and gave lectures on age- and origin determination (provenance) of minerals with LA-ICPMS. For his PhD, he has been investigating lavas from the East African Rift System and spent several months in Uganda, Tanzania and Ethiopia. Klemens authored and co-authored articles and presented results at scientific meetings.

At the Gubelin Gem Lab Klemens works as the geochemistry specialist. He is responsible for the LA-ICPMS, the inquiry and evaluation of geochemical data of gemstones. Further he develops new methods for quality control, efficient data processing and origin determination. 

Dr. Diego Bernini, Analyst
Diego studied geology at the Department of Earth Sciences of the University of Pavia (Italy), where he was working on mineralogical and spectroscopic projects during both his BSc and MSc studies. In Bayreuth (Germany) he investigated the halogen and trace element behaviour in subduction zones. Based on the resulting publications,  he earned his PhD in experimental and computational Mineralogy and Petrology at the Bayerisches Geoinstitut. Thereafter, he accepted a post-doctoral research position at the University of Milano-Bicocca (2011) and at the University of Pavia (2012), applying his mineralogical expertise in research projects in archaeometry and material sciences. At the Gübelin Gem Lab, Diego works as a research analyst, and is in charge of the spectroscopic methods of the analytical department (This responsibility comprises the FT-IR, UV-Vis-NIR and Raman spectrometric instruments and related testing procedures). Aside of the work on client stones, Diego pursues development and research projects, such as the harmonization of the spectroscopic facilities used by the Gübelin Gem Lab in different locations, or advancing the quantified evaluation and interpretation of all spectroscopic analytical data.

Administrative Coordinators

Janine Meyer

The colour photographs in Gubelin Gem Lab reports is the work of Janine, who do her utmost to show the stones in their best light. Aside from gemstone and jewellery photography, she undertakes various administrative duties such as the complete documentation of each and every item that we test in our laboratory. Other responsibilities include organising the laboratory’s business trips, as well as assuming all its administrative and secretarial functions. Janine joined the laboratory in 2014.

Isabelle Bucher

Safe, fast and reliable shipment of gemstones between the laboratory and the clients is a vital part of the service we offer. This is the responsibility of Isabelle. She interfaces with the logistics service providers, ensuring that items arrive safely at the laboratory, and – on completion of the analysis – are returned to the owners, securely and efficiently. In addition, Isabelle ensures that gemstone and jewellery certificates are present correct and supervises the content management of our website. Isabelle joined our team as Administrative Coordinator in January 2011. She worked as a customer service administrator for a telephone conferencing company in London before launching her career with us.

Martina Gügler
The maintenance and development of our laboratory management information system is Martina's duty. Fast and reliable handling of client items along with a smooth and efficient information flow between the Gubelin Gem Labs in Hong Kong and Lucerne is what Martina is assuring with her work. With almost 10 years of experience, she is equipped with a broad know-how of the daily lab business and has become a reliable source of information, not only for her Administrative Coordinator colleagues but for the entire team. Martina received her business administration training at the Gübelin Group and joined the laboratory back in 2002.

Hong Kong


Hpone-Phyo Kan-Nyunt, Lab Manager

Hpone-Phyo Kan-Nyunt has many years of experience in the analysis of treatments and the determination of origin of coloured gemstones.  Hpone-Phyo, an electrical engineer by training, began his gemmological career in 2004 at the AGTA lab in New York, followed by a position as a research coordinator and laboratory technician at the GIA in Thailand. Hpone-Phyo has experience in the spectral analysis of all types of gemstones as well as the maintenance and servicing of the laboratory analytical equipment. He joined the Gubelin Gem Lab in Hong Kong in January 2013 as a Gemmologist. A native Burmese speaker, he regularly visits mines and markets in Mogok, Mandalay and other places in Burma, further extending his knowledge and understanding of Burmese rubies, sapphires and jade. Hpone has co-authored several articles in gemmological journals, as well as chapters in textbooks regarding identifying different clarity fillers using FTIR and the Raman Spectrometer.

Angela Ip, Office Manager

Angela Ip started working for Gubelin in 2009 as our Customer Representative for the Asian region. Brought up in Canada, she holds a bachelor degree in Commerce and worked for over eight years as a customer service representative for Malca-Amit in Hong Kong. That position gave her the requisite knowledge of the processes and structures of the gem trade. Many of our Asian clients know Angela from her time at Malca. She has played a key role in setting up our new office in Hong Kong. Angela has assumed the role of Office Manager of the Gubelin Gem Lab in Hong Kong and is in charge of all non-gemmological duties.


Bonita Kwok

Bonita Kwok holds a bachelor degree in Earth Sciences and a master degree in Material Sciences, both from the University of Hong Kong. She has completed both the FGA and GG training programmes and holds a Certified Gemmologist diploma for Fei Cui and Diamond from the Gemmological Association of Hong Kong. Bonita worked as a gemmologist at the Hong Kong Gems Laboratory for over six years. In 2006 she became a gemmologist and later Chief Gemmologist at China Gems Laboratory Limited, part of the Luk Fook Jewellery Group. Bonita began working for the Gubelin Gem Lab in Hong Kong in February 2011, where she holds the position of Gemmologist.

Shuk Lam Chan
Lam started her career in the jewellery manufacturing industry where she took care of the whole process from purchasing, budgeting, production and quality control over 4 years. Working in such an environment made her interested in gemstones and their identification. She completed her FGA Diploma in 2012 and started worked as a diamond grader in the GIA laboratory. With her passion for coloured stone identification, she joined the Gubelin Gem Lab in Hong Kong as a gemmologist in October 2013.

Administrative Coordinator

Gigi Yu
Gigi Yu has held the position of Administrative Coordinator of the Gubelin Gem Lab in Hong Kong since 2012. She has many years of experience in administrative duties in Hong Kong, for example, she worked for over nine years as Export Supervisor for Malca-Amit in Hong Kong. That position gave her extensive knowledge in logistics handling for valuable items in the gem trade.  Her skills and knowledge in this field further assist the Hong Kong team in operating the take-in window service and all other non-gemmological duties. 

Our Team