Find provides evidence of earliest known use of diamond and sapphire by prehistoric people
Researchers have uncovered strong evidence that the ancient Chinese used diamonds to grind and polish ceremonial stone burial axes as long as 6,000 years ago -– and incredibly, did so with a level of skill difficult to achieve even with modern polishing techniques. The finding, reported in the February issue of the journal Archaeometry, places this earliest known use of diamond worldwide thousands of years earlier than the gem is known to have been used elsewhere.
The work also represents the only known prehistoric use of sapphire: The stone worked into polished axes by China’s Liangzhu and Sanxingcun cultures around 4000 to 2500 BC has as its most abundant element the mineral corundum, known as ruby in its red form and sapphire in all other colors. Most other known prehistoric artifacts were fashioned from rocks and minerals no harder than quartz. "The physics of polishing is poorly understood; it’s really more an art than a science," says author Peter J. Lu, a graduate student in physics at Harvard University’s Graduate School of Arts and Sciences. "Still, it’s absolutely remarkable that with the best polishing technologies available today, we couldn’t achieve a surface as flat and smooth as was produced 5,000 years ago."
Steve Bradt | EurekAlert!
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