Elizabeth is a skilled gemmologist and passionate educator with over eighteen years' experience working within the jewellery industry. Having worked across varying roles encompassing auction house specialism, museum curation, and advanced gemmological testing and grading, she now focuses exclusively on diamond education. She has worked for De Beers for seven years, creating educational content and running in-person events and workshops to encourage a deeper appreciation of natural diamonds — a subject that grows ever more beautiful as you learn.

Stefanos teaches Gemmology and Mineralogy at the Aristotle University of Thessaloniki (AUTH), Greece. He also actively contributes to the Advanced Gemmological Diploma (DUG) at the University of Nantes, France and collaborates as a Research Associate at the Laboratoire Français de Gemmologie (LFG) in Paris, France.

After a Master's degree in Geology, he completed a dual PhD in Material Sciences and in Mineralogy at the University of Nantes and AUTH respectively. At the same time, he received a DUG. He specialises in the application of non-destructive analytical methods to gems.

Stefanos has authored numerous scientific articles and regularly delivers lectures at conferences and meetings. He also serves as secretary of the Commission of Gem Materials and is a member of the Commission on New Minerals, Nomenclature and Classification of Gem Materials of the International Mineralogical Association; he is a member of the Editorial Board of G&G and Associate Editor of JoG.

Michael joined SSEF in 2022 as a research scientist and has, since April 2024, been the Head of the Diamond department at SSEF. He holds a Ph.D. from ETH Zürich in Earth Sciences, specialised in geochemistry and petrology. Today, he is mainly focusing on impurities present in both natural and synthetic diamonds to improve their identification.

He participated in the ASDI-500 development, the first automated device to screen natural colourless diamonds as small as 0.5 mm. He is involved in different research projects on natural, treated, and synthetic diamonds and in several teaching activities at the SSEF.

Dr. Aaron Palke developed an interest in minerals and gemstones searching for agates and other minerals in eastern Montana. He pursued a formal education in geology, obtaining a Bachelor of Science degree from The University of Tulsa and a Ph.D. from Stanford University.

He began his gemmological career as a Postdoctoral Research Associate at the Gemological Institute of America, where he is now the Senior Manager of Coloured Stone Research. In this role, Dr. Palke leads GIA's research efforts into geographic origin determination for rubies, sapphires, emeralds and other coloured stones, as well as improving criteria for identification of treatments for coloured stones.

Dr. Palke is a regular contributor to Gems & Gemology, serves on the journal's editorial review board, and has acted as a Guest Editor for two special issues of the journal so far.

Raquel Alonso-Perez, PhD, is Curator of the Mineralogical & Geological Museum at Harvard University (MGMH), where she is responsible for access, teaching, research, public education, and the continued development of Harvard's Earth science collections.

She holds a BSc in Geology from the University of Granada, Spain, and a PhD in Earth and Material Sciences from the Swiss Federal Institute of Technology (ETH) Zurich, and is a graduate gemmologist of the Gemmological Association of Great Britain (Gem-A). Her research has evolved from understanding Earth-forming processes to the origin of gem deposits, combining non-destructive analytical techniques with machine learning to trace gemstones and metals back to their geological sources.

She serves on the advisory boards of the Association for the Study of Jewellery and Related Arts and the Gemstone and Sustainable Development Knowledge Hub, and is an Associate Editor for GIA and Gem-A.

Dr. Emmanuel Fritsch is emeritus professor of physics at the University of Nantes (Nantes Université) in western France. He holds a geological engineering degree from the ENSG, Nancy, Eastern France, and a Ph.D. from the Sorbonne (University Paris VII) in Paris.

He worked for nearly ten years at the Gemological Institute of America (GIA) in the USA, where he became a Graduate Gemologist (GG), and was promoted manager of GIA Research from 1992 to 1995. His research is currently conducted at the Institut des Matériaux Jean Rouxel (IMN-CNRS) in Nantes.

Dr. Fritsch's interests range wide, with all aspects of science that can be applied to gems, and his self-assigned mission is to make gemmology more scientific, with special emphasis on origin of colour and luminescence. He has authored over 400 articles and collaborated on over 20 books. Before retiring, he was responsible for the DUG (Diplôme d'Université de Gemmologie) diploma, an internationally recognised advanced gemmology program.

Hanco Zwaan joined the National Museum of Natural History (now called Naturalis Biodiversity Center), Leiden, the Netherlands, in 1995, as curator of minerals and gems and became head of the Netherlands Gem Laboratory soon thereafter. Issuing gem and pearl identification reports and diamond grading reports is part of his daily work, as well as studying processes in the Earth's crust that have led to the formation of gemstones.

Dr. Zwaan has a PhD from the Free University of Amsterdam on Geology, specialising in the formation of emeralds. Apart from this focus on emeralds, he has published articles on a variety of other gemmological and mineralogical topics, among which on diamond, copper-bearing tourmaline, sapphire and pearls.

He teaches the Netherlands Gem Laboratory's education program in association with Gem-A, London (Gemmology Foundation and Gemmology Diploma, leading to the world-wide recognised qualification FGA), and is also involved in education leading to the European Gemmology diploma (FEEG).

Craig is head valuer at the Birmingham Assay Office, where he has worked as a jewellery valuer for the last 25 years. For 10 years he has also been Curator of the Office's extensive silver collection.

His responsibilities include training up the next generation of professional jewellery valuers, as well as giving talks and practical workshops on valuing, antique jewellery and silver-related topics, as well as expert witness work. He has a personal passion for the Arts and Crafts Movement and has a personal library of over 3,500 books on jewellery, gemmology and silverware. Craig has proudly been Chairman of the Midlands Gem-A branch for the last four years.

Marie-Laure is an art historian, gemmologist, jewellery expert and exhibition curator. After studying in Paris and Rome, she taught Art History for seven years at university. She was educated in Gemmology and obtained the ING, the FEEG and the GIA diplomas. She also followed courses in laboratory gemmology at Nantes University (DUG).

She taught Gemmology for twelve years and worked as a jewellery expert for auctioneers. Since 2016, she has been working for L'ECOLE as Lecturer and Researcher. Two years ago, she joined the Exhibition department. Currently, she is co-curator of the exhibition "Le Diamant rose" and co-editor of the reference book published on the occasion with Mathieu Deldicque, Director of the Musée Condé. She is also curating an upcoming exhibition on "The Emerald Routes" that will open at L'ECOLE on December 4th in Paris.

Klaus Schollenbruch studied Geology at the University of Tübingen, Germany, and completed his PhD at Goethe University Frankfurt, where he researched high-pressure and high-temperature phase transitions in Fe-bearing spinel phases. He subsequently spent four years as a gemmologist at the German Foundation of Gemstone Research (DGemG) and as an instructor for the German Gemmological Association.

Since 2015, Klaus Schollenbruch has been working at the Gübelin Gem Lab in Lucerne, Switzerland, first as a gemmologist and later as a senior gemmologist. Gemmological photomicrography is one of his main professional interests. His passion for photomicrography was recognized with second place in the GemA Photographer of the Year competition in 2024, and he teaches the Gemstone Photomicrography Workshop as part of the Gübelin Academy.

Klaus Schollenbruch has also participated in numerous gemmological field trips, conducting field research and collecting reference samples in countries including Madagascar, Brazil, Pakistan, Ethiopia, Greenland, Mozambique, and Vietnam.