Play Live Radio
Next Up:
0:00 0:00
Available On Air Stations

Advanced Stone-Polishing Techniques Employed Earlier Than Thought

Chinese craftsmen used diamonds and sapphire to polish tools thousands of years earlier than previously believed, according to new research findings. Robert Siegel talks with Peter Lu, a physics graduate student at Harvard, who applied advanced material science microscopes and tools to ancient Chinese artifacts.

Lu says the finding rewrites ancient Chinese history "from a technological standpoint."

"Somehow, in the Stone Age… they were able to sort particles that were less than a millionth of a meter across," he says.

Lu's findings were published in the journal Archaeometry.

Copyright 2022 NPR. To see more, visit

Prior to his retirement, Robert Siegel was the senior host of NPR's award-winning evening newsmagazine All Things Considered. With 40 years of experience working in radio news, Siegel hosted the country's most-listened-to, afternoon-drive-time news radio program and reported on stories and happenings all over the globe, and reported from a variety of locations across Europe, the Middle East, North Africa, and Asia. He signed off in his final broadcast of All Things Considered on January 5, 2018.