Properties of Silk Fibers Fiber structure and Characteristics The raw silk strand has an irregular microscopic appearance with striations, but these do not tend to be characteristic. Degummed silk is a translucent fiber or filament, regular without any characteristic markings for identification. Its cross-sectional microscopic appearance is of characteristic triangular shape. The handle of degummed silk is smooth and medium than soft. Only degummed silk has a distinct, soft lustre, due to the smooth fibers or filaments reflecting much of the light falling on them. Identification, burns with smell of burned hair, leaving small, easily crushable ash beads; microscopically regular, but not as regular as synthetic fibers; dissolves within 5 minutes in 10 N hydrochloric acid, i.e. strongest hydrochloric acid available from chemical supplier Weighted and raw silk may make this identification less easy.
Strength Silk is a strong fiber, which is partly responsible for its durability. However, as silk fabrics are often very fine, they can wear through more quickly than a thicker fabric. When wet, silk loses about 20% in strength, which requires that silk garments be gently handled or laundered as their usual lightness makes them rather delicate.