GIA Lab Chief Tom Moses Retiring After Nearly 50 Years of Service

Tom Moses built the language gemologists speak. After 50 years at the Gemological Institute of America, the man who helped establish the grading standards printed on every GIA diamond report in circulation today announced he will step down from his operational role in May 2026, leaving behind a body of work that reaches from a small Santa Monica laboratory to 10 GIA labs and seven schools across 10 countries.

Moses, who serves as executive vice president and chief laboratory and research officer, joined GIA in 1976 after earning his Graduate Gemologist diploma, starting at the institute's California lab before relocating to New York City to work under Robert Crowningshield. By his own account, he spent roughly 20 years working closely alongside Crowningshield. "I have been extremely privileged to work with the two greatest gemmologists and have them as my mentors," Moses said in a statement. "I will always be grateful to Richard Liddicoat for hiring me and for his selfless guidance, and to Robert Crowningshield, with whom I worked closely for 20 years, for sharing his extraordinary knowledge and for his friendship. There is no better way to honour their legacy than through continued research that advances our understanding of Earth's treasures."

Upon his departure, Moses will be named Chief of Gemological Research, Emeritus. GIA confirmed it has no plans to name a direct replacement. The transition, which GIA and Moses say they have been preparing for several years, will move research and laboratory management to existing leadership teams. Last August, GIA appointed Sriram "Ram" Natarajan as senior vice president of laboratory operations, a move that now reads as a quiet piece of succession planning. Moses will remain through the end of May, focused on continuity in client relations and research.

The scope of what Moses oversaw is considerable. During his tenure, GIA expanded from a single domestic operation into a global institution. He co-authored more than 100 technical articles for Gems & Gemology and other peer-reviewed journals, and in 2002 received the Richard T. Liddicoat Award for Distinguished Achievement, the institute's highest honor. He was elected to GIA's board of governors in 2013 and will leave that seat when he departs the operational role in May.

GIA president and CEO Pritesh Patel credited Moses with defining the institution's scientific character. "The rigor Tom brought to grading, the discipline he brought to science, and the focus he brought to our customers reflect what we aspire to be," Patel said. "His legacy lives in the standards he helped shape and the generations of professionals he guided."

Those standards now underpin how engagement ring buyers, dealers, and appraisers around the world evaluate diamonds. Every GIA grading report that lands in a jeweler's hands, or gets tucked into a ring box ahead of a proposal, carries methodology that Moses spent five decades refining. The institute has not said who, if anyone, will carry that specific weight going forward.