YINCHUAN, Oct. 30 (Xinhua) -- Chinese archaeologists have unearthed the world's smallest paleolithic ornamental beads, in northwest China's Ningxia Hui Autonomous Region.

The bead, made of a kind of eggshell and 1.26 millimeters in diameter, was discovered in an ancient site from the late Pleistocene dating between 8,000 and 12,000 years ago in Qingtongxia city.

Three similar beads, all smaller than 2 millimeters in diameter, were discovered at the same time, archeologists said Monday.

The excavation was jointly conducted by Ningxia Institute of Cultural Relics and Archeology, the Institute of Vertebrate Paleontology and Paleoanthropology and the cultural relics administration of Qingtongxia from May to August.

"It is incredible that it can be so well processed with such a small diameter. It is rare among similar ornaments unearthed in other sites around the world," said Wang Huimin, a researcher with the Ningxia Institute of Cultural Relics and Archeology.

Archeologists said the beads showed excellent craftsmanship and the aesthetic tastes of ancient humans. They said further research is needed to determine the exact purpose or meaning of the beads.

It took the archeologists five years to sift and wash thousands of cubic meters of dirt to find the beads. As many as eight sets of steel sieves were worn out in the process.

In 2016, three beads all smaller than 2 millimeters in diameter, were found at the site, among which the smallest was 1.42 millimeters in diameter.

The excavation of the site in Qingtongxia is one of China's top 10 archaeological finds of 2016, which unveiled more than 10,000 items, including stoneware, ornaments and plant seeds.