Former AGS Lab Director Pete Yantzer Dies

By Rob Bates | January 12, 2026

George Peter (“Pete”) Yantzer, the founding director of the American Gem Society’s (AGS) grading lab, died on Jan. 10, according to a story in the Roskin Gem News Report. He was 77.

Yantzer entered the world of gemology following a four-year stint in the Air Force (during which he got married). After leaving the service, he wasn’t sure what he wanted to do with his life.

“I never had a vocation or calling,” Yantzer told PriceScope in 2011. “Just didn’t know what I wanted to be or do….

“A friend whose father owned a retail jewelry store told me about the Gemological Institute of America. He told me if I became a gemologist that I could get a good job. So I used my GI Bill and went to GIA. GIA offered me a position in their New York gem trade lab. I was the seventh gemologist on the New York GIA staff in 1973.”

In 1976, he took over GIA’s West Coast lab. He left five years later and worked for over a decade as an air conditioning and heating contractor.

But in 1996, the industry called him back, and he became the first executive director of the AGS’ diamond grading lab. It quickly established itself as one of the first gem labs to offer a cut grade. Today, just about every diamond grading report, including those issued by GIA—which took over the AGS lab in 2022—feature a cut grade.

Yantzer retired in 2015, after leading the lab for two decades. Upon his retirement, he told JCK he believed the AGS lab helped change the way the industry thinks of cut.

“What we did absolutely improved the quality of cutting in the diamond industry,” he said. “I remember after we introduced it, at the Vancouver [AGS] Conclave, everyone was calling me a scientist. I am not a scientist. I’m just a guy.”

In 2005, the AGS gave Yantzer the Robert M. Shipley Award, its highest honor.

Following his passing, AGS executive director Katherine Bodoh wrote on Facebook: “Even in retirement, Peter often visited AGS headquarters, sharing stories from his time at the lab and in the industry—always lighting up the room with his warmth and signature smile. He truly embraced life and often said, ‘It’s a great day to be alive, isn’t it?’”

When I spoke with Yantzer in 2022, he told me he’d taken up photography as a hobby, and sent me some photos. Two are below.