How to distinguish: good silk is made of high quality silk with bright color, neat silk road, strong adhesion, fine silk and strong hand feeling; Inferior silk is white, dull, with many impurities and dark yellow color. High-quality silk has pearl-like color and diffuse reflection on light. Clean impurities are few, and the Silk Road is orderly and tidy; However, poor quality silk, due to the addition of chemicals such as bleach, often looks pale, dull and wet, with more impurities, and the silk road is chaotic. The second touch: the good silk is made of high-quality silk, which is smooth, elastic, flat and not caked, while the inferior silk is rough and feels poor, with cocoons, stalks and cocoons. High-quality silk feels soft, smooth and elastic, without lumps; Inferior silk, on the other hand, feels rough, inflexible and moist, and there are relatively many cocoon stems, cocoons, raw cocoons and pupae sloughing. Three smells: good silk is made of high quality silk, without adding white silicone oil, which has a natural smell. Add silicone oil and softener to inferior silk to increase smoothness. Silk with oily or musty smell is inferior. Four burns: Good silk has a strong burnt smell when burned by real silk, and stops burning as soon as it leaves the flame. The burnt noodles are granular and can be rubbed into powder by hand. Inferior silk has a pungent oil smoke when it burns, and it has almost no smell of burnt hair, and it keeps burning after leaving the flame. Five pulls: Good silk is pulled hard by hand with high quality silk, which is not easy to pull, while inferior silk will be pulled gently by hand, and some will be pulled into a bundle. The better the strength and elongation of silk, the better the quality. The research shows that the tensile strength of super-grade mulberry silk should be greater than that of iron wire with the same diameter. High-quality silk with excellent elasticity; The fiber properties of inferior silk, such as tensile strength and resilience, are poor.