Silk is the strongest natural textile in the world. This textile was just recently surpassed in strength by a lab-engineered biomaterial, but it remains the strongest fabric made through natural processes.

Comprised of natural protein fiber, silk mainly consists of fibroin, which is a protein that certain types of insect larvae secrete to make cocoons. While other insects also produce silk-like substances, most of the world’s silk is derived from Bombyx mori larvae, which are worms that only live on mulberry trees.

Originally, human beings harvested wild silk to make rudimentary fabrics. While worms spin silk in the wild in parts of China, India, and Europe, wild silk is never available in large enough quantities to satisfy the needs of full-blown textile production.

The cultivation of domesticated silk originated in China. One piece of archaeological evidence dates the use of silk textiles in China back to 6500 BC, and the ancient Chinese certainly used silk as early as 3600 BC.

While historical records of the origin of silk manufacturing in China are largely lacking, Chinese legends credit Empress Leizu with the development of sericulture, which is the art of making silk. In the early days of Chinese culture, only the nobility wore silk, but as Chinese civilization developed and became wealthier, commoners started wearing this soft and durable fabric as well.

Silk production in China eventually led to the development of prominent pre-industrial trade routes. The Silk Road stretched from China to Western Europe, and Chinese merchants traveled up and down this trade route to exchange silk for the commodities of distant nations.

For generations, the secrets of sericulture were the most prized and guarded pieces of knowledge of the Chinese nobility, but eventually, information on how to make refined silk spread to Korea and India during the first few centuries AD. India, Thailand, and other Asian nations already had highly-developed sericulture processes at this point, but the Chinese method of making silk was considered to be superior.

Based on limited legends and historical records, silk may have also been produced in the West during the distant past. Whatever the case may be, silk was highly prized by Westerners as far back as Roman times, and the popularity of this rare and mysterious substance only grew during the medieval period.

By the 11th century AD, silk production was widespread throughout Europe. Many Italian city-states, such as Lucca, Venice, and Florence, were highly economically reliant on silk production during the Middle Ages, and the silk industry gradually spread to France and Spain.

King James, I introduced silk production to the New World in the 17th century, and American states such as Connecticut and Massachusetts rapidly became hubs of silk production. World War II cut America off from Asian silk, and as a result, American corporations developed synthetic replacements such as nylon.

While the silk industry has expanded greatly during the last century, the processes used to make this fabric are still largely the same as they were in the ancient world.

Once silkworm breeders have harvested silkworm cocoons, they usually expose them to high heat to prevent the mature worms from emerging. Some animal rights activists protest this practice; they contend that it’s possible to harvest silk without killing silkworms, but not much credence is given to this position.

After the cocoons have been heated, silk producers carefully unravel the threads that the silkworms meticulously put into place. To do so, the silk cocoons may be boiled briefly to remove a small amount of the sericin in the cocoons, which is the glue-like substance that silkworms excrete to form their metamorphosis chambers.

Silkworms make cocoons out of one long strand of fiber, which means that a fully unraveled cocoon results in a single string of silk. To unravel a cocoon, a silk worker or an automated machine will brush the cocoon to find the loose end and load it through a porcelain eyelet onto a reel that unravels the silk strand.

As the silk strand loads onto the reel, it is automatically attached to another strand to make a continuous string. The sericin in the silk strand helps the strands stick together. Next, silk producers twist these long strings together to make yarn.

Silk producers may perform a variety of post-production processes to create silk yarn that has certain desired attributes, and then the silk yarn is put through a roller to make it more uniform. At this point, the yarn is ready to be woven into a garment or another type of textile.

Before they weave it, most silk textile manufacturers dye their yarn, and they may bleach it. These manufacturers may also stiffen or steam silk to achieve desired attributes.