Silk is a natural protein fiber, some forms of which can be woven into textiles. The best type of silk is obtained from cocoons made by the larvae of mulberry silk worm. The shimmering appearance for which silk is prized comes from the fibers triangular prism-like structure which allows silk cloth to refract incoming light at different angles.

Silks are produced by several other insects, but only the silk of moth caterpillars has been used for textile manufacture. Silk when held is smooth; soft textured and is not slippery like other synthetic fibers. It is very thin, strong finely meshed silk which can be used for archival work.

Silk thread is strongest of all natural fibers and does not lose up to 20% of its strength when wet. This is poor conductor of electricity making it comfortable to wear in cool weather. This thread can become weakened if exposed too much of sunlight. There are many lustrous colours available in silk. This thread is wonderful in heirloom embroidery, smocking, shadow work embroidery, and samplers, cross stitch, needle painting and black work.