Founders & Senior Gemmologists
Willy Bieri
Chief Science Officer (CSO)
Willy Bieri brings over 20 years of specialised expertise in gemstone microscopy and advanced analytical methods. Having established and led laboratory operations across Switzerland, Paris, Hong Kong, and Bangkok, he has accumulated an exceptional range of hands-on analytical experience. As Chief Science Officer, Willy is responsible for maintaining the highest standards of scientific integrity across all laboratory operations, ensuring that every assessment reflects the precision and rigour that defines our work.
Lawrence Hahn
Chief Operating Officer (COO)
Lawrence Hahn combines over 15 years of gemmological expertise with 9 years of previous commercial and operational gem trade leadership. His experience spans laboratory management across Hong Kong, New York, Sri Lanka, and Bangkok, where he has built a career grounded in the analysis of a vast and diverse range of gemstones. With a strong foundation in gem trade commerce, valuation, and market strategy, complemented by hands-on experience in pearl farming and gemstone mining, Lawrence brings a uniquely comprehensive perspective to the business of gemmology. As Chief Operating Officer, he oversees the strategic commercial direction and operations of the company.
Matthias Alessandri
Chief Technology Officer (CTO)
Matthias Alessandri brings over 14 years of gemmological laboratory experience, complemented by a professional background in banking and information technology. Having worked across laboratories in Hong Kong, Sri Lanka, and Bangkok, he has developed a deep understanding of laboratory operations at scale and across a wide spectrum of gemstone types. As Chief Technology Officer, Matthias leads the development and optimisation of laboratory systems and data-driven processes, ensuring operational efficiency and analytical precision across all aspects of the business.
Our Values
Independence
SIG is a self-funded laboratory group, free from external conflicts of interest. This structure ensures impartial and independent analysis in every assessment.
Precision
Each gemstone is analysed without compromise and is assessed on its own merits, with conclusions derived from scientific findings and expert judgement, applied within SIG grading criteria and unaffected by external considerations.
Experience
Our laboratories are led by seasoned gemmologists with decades of senior-level laboratory grading and commercial experience.
Transparency
Our reports are written to be understood, presenting findings clearly and concisely within established market standards.
Vision
Through Swiss precision and global reach, we transform clarity into confidence – Creating a world where every coloured gemstone's story is verified, transparent, and every report is grounded in trust.
«Multiple reports are a reality of today’s gem trade. Our vision is for SIG to be both the first and the final report the market relies on by bridging market inefficiencies — delivering clarity, consistency, and confidence so each gemstone can move forward on its correct journey through the value chain.»
Lawrence Hahn, COO