Cashmere is a thin layer of fine wool that grows in the outer cortex of the goat and covers the root of the coarse hair of the goat. It grows when it is cold in winter, resists the wind and cold, falls off when it turns warm in spring, and adapts to the climate naturally. It is a rare special animal fiber. Cashmere is very precious not only because of its rare output (only accounting for 0.2% of the total output of animal fiber in the world), but also because of its excellent quality and characteristics. It is considered as "fiber jewel" and "fiber Queen" in terms of its price per gram in the transaction. It is incomparable with all the textile materials available to human beings at present, so it is also called "soft gold". About 70% of cashmere in the world is produced in China, and its quality is better than other countries.
Cashmere fiber is composed of scale layer and cortex layer. There is no medulla layer and irregular crimp, but the crimp number is less than that of fine wool. The average diameter of cashmere fiber is 15-16 μ m and the length is mostly 35-45 mm. The strength and elasticity of cashmere are better than wool, but it is more sensitive to acid, alkali and heat. Even under the weaker treatment condition, the damage of fiber is more obvious.