April 7, 2006
In Lingjiatan, Hanshan County of Anhui Province in China, archaeologists have discovered a primitive tribal site that was inhabited 5,000 years ago.
Remarkably advanced drilling technology and the world’s earliest stone drill bits were found at the site. Archaeology professor Zhang Jingguo said there are still many mysteries in the Lingjiatan ruins waiting to be solved.
……Under 50 times magnification, they found a little hole on the back of a jade statue.
The diameter of the hole is only 0.15 millimeters. This would have required a drill with a diameter slightly thicker than a strand of hair. …