Silk is a fine, tough, elastic fiber produced by caterpillars, commonly called silkworms. Silk is one of the oldest known textile fibers. Chinese tradition credits Lady Hsi-Ling-Shih, wife of the Emperor Huang Ti, with the discovery of the silkworm and the invention of the first silk reel. Dating to around 3000 BC, a group of ribbons, threads, and woven fragments was found in China. Also found, along the lower Yangzi River, were 7,000 year-old spinning tools, silk thread, and fabric fragments.

Silk filament was first woven into cloth in Ancient China. The Chinese successfully guarded this secret until 300AD, when Japan, and later India, learned the secret. In 550 AD, two Nestorian monks were sent to China to steal mulberry seeds and silkworm eggs, which they hid in their walking staffs, and then brought back to Rome. By the 17th century, France was the silk center of the West. Unfortunately, the silkworm did not flourish in the English climate, nor has it ever flourished in the US.

Sericulture is the term for the raising of silkworms. More than 500 tiny eggs are laid by the blind, flightless moth, Bombyx mori. After hatching, the tiny worms eat chopped mulberry leaves continuously until they are ready to spin their cocoons. After gathering the complete cocoons, the first step in silk manufacturing is to kill the insects inside the cocoons with heat. The cocoons are then placed in boiling water to loosen the gummy substance, sericin, holding the filament together. The filament is unwound, and then rewound in a process called reeling. Each cocoon’s silk filament is between 600 and 900 meters long. Four different types of silk thread may be produced: organzine, crepe, tram, and thrown singles. During the last 30 years, in spite of the use of man-made fibers, world silk production has doubled.

Raw silk is traded on the Kansai Agricultural Commodities Exchange (KANEX) in Japan. Dried cocoons are traded on the Chuba Commodity Exchange (CCE). Raw silk and dried cocoons are traded on the Yokohama Commodity Exchange.

Supply – World production of silk in 2000, the latest reporting year, rose +4.8% to 110,000 metric tons, recovering to a 5-year high after hitting a trough of 85,000 metric tons in 1997. China is the world’s largest producer of silk by far with 69% of world production. Other producers include India with 14.5% of world production, and North Korea and Turkmenistan, each with 4.5% of world production.

Trade – The world’s largest exporters of silk are China with 45.0% of world exports, Hong Kong with 3.2%, and North Korea with 2.8%. The world’s largest importers of silk (1999) were Italy (with 15.3% of world imports), Japan (11.7%), India (8.8%), and South Korea (7.0%).