Featured Research

from universities, journals, and other organizations

Chinese Used Diamonds To Polish Sapphire-rich Stone In 2500 BC

Date:
February 16, 2005
Source:
Harvard University
Summary:
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.

CAMBRIDGE, Mass. -- 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.

Related Articles


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."

Lu's work may eventually yield new insights into the origins of ancient China's trademark Neolithic artifacts, vast quantities of finely polished jade objects.

Lu began the research in 1999, as a Princeton University undergraduate. He studied four ceremonial axes, ranging in size from 13 to 22 centimeters, found at the tombs of wealthy individuals. Three of these axes, dating to the Sanxingcun culture of 4000 to 3800 BC and the later Liangzhu culture, came from the Nanjing Museum in China; the fourth, discovered at a Liangzhu culture site at Zhejiang Yuhang Wujiabu in 1993, dates roughly to 2500 BC.

"What's most amazing about these mottled brown and grey stones is that they have been polished to a mirror-like luster," Lu says. "It had been assumed that quartz was used to grind the stones, but it struck me as unlikely that such a fine finish could be the product of polishing with quartz sand."

Lu's subsequent X-ray diffraction, electron microprobe analysis, and scanning electron microscopy of the four axes' composition gave more evidence that quartz could not have polished the stones: Fully 40 percent corundum, the second-hardest material on earth, the only material that could plausibly have been used to finish them so finely was diamond.

To further test whether diamond might have been used to polish the axes, Lu subjected samples of the fourth axe, 4,500 years old and from the Liangzhu culture, to modern machine polishing with diamond, alumina, and a quartz-based silica abrasive. Using an atomic force microscope to examine the polished surfaces on a nanometer scale, he determined that the axe's original, exceptionally smooth surface most closely resembled -– although was still superior to -– modern polishing with diamond.

The use of diamond by Liangzhu craftsmen is geologically plausible, as diamond sources exist within 150 miles of where the burial axes studied by Lu were found. These ancient workers might have sorted diamonds from gravel using an age-old technique where wet diamond-bearing gravels are run over a greased surface such as a fatty animal hide; only the diamonds adhere to the grease.

The next known use of diamond occurred around 500 BC; it was used after 250 BC in ancient India to drill beads. The earliest authors to reference what is likely diamond, Manilius and Pliny the Elder, lived in Rome during the first century AD.

Lu's co-authors are Paul M. Chaikin of New York University; Nan Yao of Princeton University; Jenny F. So of the Chinese University of Hong Kong; George E. Harlow of the American Museum of Natural History; and Lu Jianfang and Wang Genfu of the Nanjing Museum. The work was supported primarily by Harvard University's Asia Center, with additional support from MRSEC grants and Princeton University's Department of Physics.


Story Source:

The above story is based on materials provided by Harvard University. Note: Materials may be edited for content and length.


Cite This Page:

Harvard University. "Chinese Used Diamonds To Polish Sapphire-rich Stone In 2500 BC." ScienceDaily. ScienceDaily, 16 February 2005. <www.sciencedaily.com/releases/2005/02/050213135123.htm>.
Harvard University. (2005, February 16). Chinese Used Diamonds To Polish Sapphire-rich Stone In 2500 BC. ScienceDaily. Retrieved October 24, 2014 from www.sciencedaily.com/releases/2005/02/050213135123.htm
Harvard University. "Chinese Used Diamonds To Polish Sapphire-rich Stone In 2500 BC." ScienceDaily. www.sciencedaily.com/releases/2005/02/050213135123.htm (accessed October 24, 2014).

Share This



More Fossils & Ruins News

Friday, October 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Fossil Treasures at Risk in Morocco Desert Town

Fossil Treasures at Risk in Morocco Desert Town

AFP (Oct. 23, 2014) Hundreds of archeological jewels in and around the town of 30,000 people prompt geologists and archeologists to call the Erfoud area "the largest open air fossil museum in the world". Duration: 02:17 Video provided by AFP
Powered by NewsLook.com
Oldest Bone Ever Sequenced Shows Human/Neanderthal Mating

Oldest Bone Ever Sequenced Shows Human/Neanderthal Mating

Newsy (Oct. 23, 2014) A 45,000-year-old thighbone is showing when humans and neanderthals may have first interbred and revealing details about our origins. Video provided by Newsy
Powered by NewsLook.com
Weird-Looking Dinosaur Solves 50-Year-Old Mystery

Weird-Looking Dinosaur Solves 50-Year-Old Mystery

Newsy (Oct. 23, 2014) You've probably seen some weird-looking dinosaurs, but have you ever seen one this weird? It's worth a look. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins