Scientists have found evidence of silk dating back 8,500 years after testing soil samples from a Neolithic site in Henan province.

The discovery greatly advances the study of the material's history and Neolithic cultures, according to a report released on Monday by the University of Science and Technology of China.

Gong Decai, a professor with the college's scientific archaeology department, spent almost six years completing the research, which he also included in a recent article for Plos One, an international academic journal.

He said his team found evidence of prehistoric fibroin, an insoluble protein found in silk, in soil samples collected from three tombs at Jiahu, a Neolithic site in Henan's Wuyang county that had settlers as early as 7,000 BC.

Compared with other ancient relics such as pottery and bone or stone tools, which are often found in archaeological digs, textiles are highly susceptible to degradation, meaning it's rare they are preserved for thousands of years.

Gong said earlier studies had found proof of weaving skills and tools in the Neolithic period, such as spinning wheels, but until now, there had been a lack of direct evidence proving the existence of silk.

"The direct biomolecular evidence shows the existence of prehistoric silk fibroin, which was found in 8,500-year-old tombs," he said, adding that rough weaving tools and bone needles were also excavated, supporting the theory that Jiahu settlers possessed basic weaving and sewing skills.

The site is famous for the discovery of the earliest playable musical instrument, the bone flute; the earliest mixed fermented beverage of rice, honey and fruit; and the earliest domesticated rice in northern China.

"The archaeological discoveries are endless," Gong said. "With the application of science and technology, more methods have contributed to discoveries, which boost our knowledge of Neolithic civilizations step by step."

Zhu Lixin contributed to this story.

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