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Gemmological Certification Services (GCS)

Deborah Mazza

Gemmological Certification Services was established in the heart of London’s Mayfair in 2014. We are the UK's leading gemmological laboratory for the origin determination of coloured gemstones; identification of synthetic material, including laboratory grown diamonds; differentiating natural and cultured pearls; and detecting treatment in all the major gemstones. Working in collaboration with Claude Bernard University in Lyon, France, we uphold a high academic standard, with a fully trained team of gemmologists and the most up-to-date technology. We are proud to provide gemmological certification services to the most prestigious jewellers and auction houses in the UK and worldwide.

Our parent company, the antique jewellery specialists, Gemroad had been established on the premises a decade earlier by Stephane Cohen-Scali, whose interest in gemstones stems back to his childhood, having grown up in the family jewellery business in Paris. France. As an interest in gemstones can only take one so far, Stephane went on to pursue his gemmological studies at the Institut National de Gemmologie and Claude Bernard University, obtaining a gemmological degree and diploma respectively. After founding Gemroad, Stephane, recognising a need for such a service, set up a gemmological laboratory in London.

The company is now managed by his daughter, Stephanie Seror, who has grown the team to three times its original size over the past year. With an experienced tutor on staff, we are now able to deliver gemmological education to the those with an interest in pursuing this fascinating and ever evolving subject.

Our pooled knowledge, coupled with our day-to-day operations as a laboratory, place us in a prime position to offer the most comprehensive level of gemmological education in the UK. We are looking forward to working with the World Gemmological Foundation.

Beth West, the principal tutor at GCS, is a gemmologist, educator and writer with over fifteen years’ experience in the jewellery industry in varying senior roles. As a Fellow and Diamond Fellow of the Gemmological Association of Great Britain and a member of the Federation of European Education in Gemmology, she has a wealth of passion for her subject, and is driven by a desire to share her knowledge with others. Outside of her immediate professional responsibilities as the laboratory director, she has worked as a diploma level tutor for Gem-A for over five years, and also as a consultant for De Beers Institute of Diamonds, designing and writing educational content. She is also involved in number of other projects, with a particular focus on the importance of gemmological education along the supply chain, which drives her work as a committed volunteer for the NGO, Diamonds for Peace.

Beth will be working together with our team-skilled gemmologists to support your learning experience with the World Gemmological Foundation.

Visit Gemmological Certification Services (GCS) at:

GCS Location GCS Lab GCS Lab Beth West


The World Gem Foundation is a not-for-profit organization that was formed in 2015 with the mandate to provide quality and affordable gemmological training to students, jewellers and professional gemmologists.

Currently consisting of seventeen national and regional gem academies in the United Kingdom, Holland, the U.S, Canada, Spain, Belgium, France/Monaco/Switzerland, Scandinavia (Norway, Sweden, Finland, Denmark and Iceland), Eastern Europe (Bulgaria, Croatia, Czech Republic, Hungary, Macedonia, Poland, Republic of Kosovo, Republic of Moldova, Romania, Russia, Serbia, Slovak Republic and Slovenia), East Africa (Burundi, Comoros, Djibouti, Eritrea, Ethiopia, French Southern and Antarctic Lands, Kenya, Madagascar, Malawi, Mauritius, Mayotte, Mozambique, Réunion, Rwanda, Seychelles, Somalia, Somaliland, Southern Sudan, Tanzania, Uganda, Zambia, Zimbabwe), South Central Africa (Angola, Cameroon, Central African Republic, Chad, Democratic Republic of the Congo, Equatorial Guinea, Gabon, Republic of the Congo, Sao Tome and Principe, Botswana, Eswatini, Lesotho, Namibia, South Africa), West Africa (Ascension, Benin, Burkina Faso, Cape Verde, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, Mauritania, Niger, Nigeria, Saint Helena, Senegal, Sierra Leone, The Gambia, Togo, Tristan da Cunha), Central America (Mexico, Guatemala, Honduras, Nicaragua, El Salvador, Costa Rica; Belize and Panama), South America (Brazil, Argentina, Bolivia, Chile, Colombia, Ecuador, Paraguay, Peru, Uruguay, Venezuela, Guyana and Suriname), the Caribbean (Aruba, Bahamas, Barbados, Belize, Cayman Islands (U.K.), Cuba, Puerto Rico, Curaçao (Netherlands), Dominican Republic, Guyana, Haiti, Jamaica, Antigua and Barbuda, Dominica, Grenada, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Sint Maarten, Suriname, Trinidad and Tobago and Turks and Caicos), Sri Lanka and India. We plan to establish more academies around the world in 2023.

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