Possibly just a bum report from one of the ancient writer's sources -- but it may have been silk, or one of the alternative silk types and this is the only record of it. The Indus Valley civ had silk around the same time as the Neolithic Chinese, but it wasn't the same source (they used silk moths).
https://www.worldhistory.org/Silk/
Silk in Antiquity
Definition
Mark Cartwrightby Mark Cartwright
published on 28 July 2017
https://www.youtube.com/watch?v=PAu5SLSLXxU
The Silk Road: Trade Route of the Ancient World
March 26, 2021
World History Encyclopedia
The Silk Road was a network of trading routes that connected a number of different regions in the ancient world, stretching over four thousand miles from China, through India and Asia Minor and through Mesopotamia and the African continent, all the way to Greece, Rome and Britain. These routes were formally established by the Han dynasty of China in 130 BCE and although it was a number of different trading routes, the name the Silk Road has always been favoured. Despite its name, not only silk travelled along these routes, but many other goods, too!
https://core.ac.uk/download/pdf/188079348.pdf
The Archaeology of Early Silk
Irene Good
Harvard University, igood@fas.harvard.edu
2002