What type of fibers are spun by silk worms to create silk?

Silk is produced by silk worms, specifically from the cocoons they create, which are made up of proteins. The key component of silk is fibroin, a protein that forms the structure of the silk fibers. This categorizes silk as a protein fiber, which is derived from the secretions of living organisms.

Protein fibers, such as silk, are known for their unique properties, including a lustrous sheen, strength, and softness, making them highly valued in textile production. This contrasts with other types of fibers such as cellulose fibers, which are derived from plants, synthetic fibers that are man-made from chemical substances, and mineral fibers, which come from natural mineral sources. In the context of silk production, it is the protein nature of the fibers that accounts for its luxurious qualities and applications in fashion and textiles.