What is silk?

Silk is a natural protein fiber. The word “silk” comes from Ancient Greece (σηρικός, serikos) and Asia (Chinese silk, Manchurian sirghe, Mongolian sirkek).

Some forms of silk are used into textiles.


Silk is produced by certain insect larvae, which are producing protein fiber to form cocoons. Generally silk is produced from the mulberry silkworm Bombyx mori larvae cocoons. Insects aren’t the only one which produces silk – bees, wasps, ants, silverfish, mayflies, thrips, leafhoopers, beetles, lacewings, fleas, flies, midges and spiders are producing it too.


The production process of silk consists of several steps – firstly, for extracting raw silk, silkworms are cultivated on mulberry leaves, secondly, when silkworms are pupating in their cocoons, they are dissolved in boiling water, thirdly, dissolved cocoons are formed in long fibers, fourthly, these fibers are fed into the spinning reel.

Physical characteristics

Silk shimmers because of silk fibres triangular prism-like structure. Bombyx mori silkworms silk fibers have a triangular cross section with rounded corners, and it’s 5 to 10 micrometers wide, but other silkworms silk fibers cross-section can vary in shape and diameter. Silks texture is smooth and soft, but is not slippery as many synthetic fibers. Silk is known as one of the strongest natural fibers, but unfortunately it loses at least 20% of its strength when it’s wet. Silk has a good moisture, but bad elasticity. Silk can be weakened by sunlight and be attacked by insects.

Chemical properties

Natural silk consists of two proteins – fibroin, which is the structural center of the silk, and sericin, which is the sticky material surrounding it.


Silk is used in clothing (daily, high fashion, national), furnishing accessories, wall coverings, window treatments, rugs, bed and wall hangings. Silk is used in such specific things as parachutes, bicycle tires, comforter filling and artillery gunpowder bags.