Our Team
A passionate team of internationally certified gemologists dedicated to precision, integrity, and excellence in gemstone analysis. With laboratories in Antwerp, Belgium and Shanghai, China, we serve clients across Europe and Asia.
Leadership
Co-founders guiding ALGT's mission with decades of expertise

Segers Marc
Marc Segers is the co-founder of ALGT, which he established together with Mingyue in 2019. He plays an active role in gemstone testing, gemmological education, and laboratory management. He obtained his diamond grading and gemmology diplomas in the 1990s. From 1997 to 2001, he worked as a gemologist and instructor at the Gemological Institute of HRD in Antwerp, Belgium. He later joined the Worldwide Education Department of the International Gemological Institute (IGI) in Antwerp. Marc holds a FEEG diploma and is a member of the Academie voor Mineralogie (ACAM), Belgium, as well as the Raad voor Aardwetenschappen vzw (Council for Earth Sciences). In 2019, he was awarded the Laureaat Eliten van den Arbeid (KIEA) Gold Medal by the King of Belgium in recognition of his expertise in diamonds.
Qualifications & Expertise

Mingyue Yang
Mingyue Yang is the co-founder of ALGT, established together with Marc Segers in 2019. She serves as Director and Senior Gemmologist, with expertise in gemstone testing, laboratory operations, and gemmological research. Before joining ALGT, she worked as Senior Gemologist at Antwerp International Gemological Laboratories (AIG) in Belgium. Earlier, she held senior positions at ARY Jewellery LLC., ARY Group of Companies in Dubai, where she helped establish a fully equipped diamond and gemstone laboratory and gemmological academy, and at Zhongrong Holdings Group in Beijing, where she advised on the acquisition of important diamonds, coloured gemstones, pearls, and jadeite, while also supporting collection management and auction organisation. She has also contributed to gemmological research, including pearl-related publications and academic work on cultured pearl treatment and colouration.
Qualifications & Expertise
Sun Sijie
Sun completed his GG diploma in 2016. In 2019, he participated in the founding of ALGT Gem Laboratory. In 2022, he was responsible for preparing the establishment of the second laboratory in Shanghai, China. He currently oversees the daily administrative operations of the Shanghai laboratory.
Qualifications & Expertise
The Team
Specialists across gemology, analytics, operations, and technology
Dominique Flies
Dominique is a gemologist and diamond grading specialist with extensive experience in diamond analysis, certification, and education. Before joining ALGT, he worked as Senior Diamond Grader at the International Institute of Diamond Grading & Research at The De Beers Group of Companies. He also previously served as Diamond Grader and Gemologist at IGI in Antwerp, and as a gemologist at the Laboratoire Français de Gemmologie in Paris. Dominique holds qualifications in gemology, diamond grading, marketing, and management, combining strong technical expertise with valuable client communication and commercial insight.
Qualifications & Expertise
Ye Cao
Ye Cao is an experienced gemologist with a strong background in gemstone identification, laboratory management, and jewelry quality control. He previously worked at the ZhongBao Centre of Gem & Jade Identification in Shanghai and at AIGS Shanghai, where he focused on advanced gem testing instruments and the overall management of the gem testing laboratory. He holds the Occupational Qualification Certificate of Gemstone Inspector, Senior Technician, and is also a Certified Gemologist in the People's Republic of China.
Qualifications & Expertise
Shiqi Le
Shiqi Le is responsible for colored gemstone testing, microscopic examination, and instrument-based analysis. She graduated in Gem and Material Technology and later pursued continuing education in specialized jewelry identification. Before joining ALGT, she worked at AIGS for three years, focusing mainly on colored gemstone identification.
Qualifications & Expertise
Yunqing Zhu
Yunqing Zhu is a jewelry visual designer responsible for graphic design and web UI design in the laboratory.
Qualifications & Expertise
Leon Guan
Leon graduated from the Department of Electrical Engineering at Southeast University in China and has previously worked at Baosteel and BearingPoint. With more than 30 years of programming experience, he is currently responsible for the design, development, and support of ALGT's internal information systems as well as the laboratory's website and digital platforms.
Qualifications & Expertise
Our Values
The principles that guide every analysis
Precision
Every gemstone is analyzed with meticulous attention to detail using advanced instrumentation and classical gemological methods.
Integrity
Independent and unbiased certification you can trust. Our reports reflect only the truth of each gemstone.
Innovation
Continuously investing in cutting-edge technology and methodology to stay at the forefront of gemological science.
Excellence
From training to reporting, we pursue the highest standards in every aspect of our work.