September 7, 2013—Jade bi (discs), from China, that resemble modern-day CD's or donuts, and date to the late Neolithic Period, Liangzhu culture (ca. 3300-2250 BC) remain a mystery. Researchers at the Smithsonian's Freer and Sackler galleries in Washington, D.C., are among those who have studied the bi.
Transcript
Janet Douglas, Conservation Scientist, Smithsonian Freer and Sackler Galleries:
"Most people, I think, when they're thinking about jade imaging a bright green material that we commonly see in jewelry. But the Chinese jade tends not to be that bright green material. It tends to be darker, more subtle colors."
Keith Wilson, Curator of Ancient Chinese Art, Smithsonian Freer and Sackler Galleries:
"The Freer possesses one of the large collections of ancient jades from the Neolithic culture that we now call Liangzhu. The culture is names after its first discover site near Hangzhou, which is essentially southwest of Shanghai."
"Bi discs are essentially round, flat donuts. They're created from, in general, nephrite which is a specific kind of jade material. They were clearly important to the society that created them. They're found in Chinese tombs, elite burials, often in large number. The on-going mystery is exactly why they were made and why they were put in tombs."
Janet Douglas, Conservation Scientist, Smithsonian Freer and Sackler Galleries:
"I think that the shape of the bi was chosen because they learned how to work that shape using rotating tools, a turn-table or some sort of mechanical device to rotate the jade. We have a lot of ideas about how jades were worked. And we are quite sure they were largely worked with mineral abrasives. So through the abrasive process of rubbing the surface of the jade one way or another, whether it's sawing or creating a drill hole, mineral abrasives would have been used because not tool would have been available during the Neolithic period."
Keith Wilson, Curator of Ancient Chinese Art, Smithsonian Freer and Sackler Galleries:
"Clearly it was not made by average people. These were highly trained artisans who were responsible for making these objects. The material itself is rare. Notoriously difficult to work so that creation of these objects in nephrite represent a great expenditure of social wealth at the time."
Janet Douglas, Conservation Scientist, Smithsonian Freer and Sackler Galleries:
"Normally when jade objects come into our laboratory for examination, the first thing we do is we studied it visually under a microscope. They curator usually would like to know the mineral composition of the object. We use techniques such x-ray diffraction and Fourier transform-infrared spectroscopy to analyze the jade material. We look for evidence of manufacturing to learn how the object was made. That includes looking a the overall shape and form of the object and more detailed look at the tool marks left on the surface of the jade."
Keith Wilson, Curator of Ancient Chinese Art, Smithsonian Freer and Sackler Galleries:
"Because of the development of archaeology in China and the great interest in Liangzhu culture, it's encouraged us here at the museum to use our collection of some 125 objects as a kind of sample to improve our understanding of the manufacturing techniques of this ancient culture."
