Models display designer Cheng Yingfen's 2015 spring/summer collection, which highlights Idili silk, in Beijing. [Photo/China Daily]

Idili silk has been worn by people in the Xinjiang Uygur autonomous region for nearly 3,000 years. But for those outside of the region, the fabric was largely unknown until a recent fashion show in Beijing.

Xinjiang fashion designer Cheng Yingfen showed the 2015 spring/summer collection as part of the China Fashion Week in October. The collection presents evening dresses, gowns, blazers and pencil skirts, all highlighting the Idili silk.

The apparel can only be found in Hetian prefecture in Xinjiang. The threads are dyed with the juice of plants and flowers before being hand-woven into different patterns.

There is no written record of the technique. For thousands of years, the patterns are memorized by local craftsmen and passed down within their families. People wear it only at parties, weddings and family gatherings.

Now, as young people move out to the cities to find jobs, few are willing to stay at home to learn the technique.

Cheng and Zhao Yi, general manager of Siluzhixing Garment Co, both grew up in Xinjiang wearing Idili silk. The two traveled more than a thousand miles from Xinjiang's capital Urumqi to Hetian to do field research about the fabric.

They found that there are more than 1,000 family workshops in a single county that make Idili silk. However, the number of orders is declining rapidly.