GIA's Tom Moses Examines the World's Second

For Tom Moses, it was a peak moment in his career.

“Think of something that’s as big as your closed fist — and it’s a diamond that weighs slightly more than one pound. There’s a sense of overwhelming disbelief and excitement that comes over you,” he said.

Moses, the executive vice president and chief research and laboratory officer at the Gemological Institute of America (GIA), was recounting his experience July 14 and 15 at the institute’s laboratory in Gaborone, Botswana. That’s where he examined the world’s second-largest diamond — the 2,492-carat Lucara Diamond discovered in August 2024 at Botswana’s Karowe Mine, which has a track record of producing rare and large, high-quality diamonds.

GIA, a nonprofit organization, has a team of more than 60 scientists, researchers and technical