Cashmere wool comes from a goat rather than sheep; and unlike mohair, the other well-known goat wool, cashmere does not come from a single breed of goat; although there is a cashmere goat, and although it is the ideal source of the wool, in fact the term applies to wool that can be taken from a variety of breeds. The requirement is that the average diameter of each wool fibre does not exceed 19 microns, according to US trade legislation.
Cashmere comes primarily from the finest hair of the neck region of goats, normally harvesting during the spring moult. The fabric produced from it is fine in texture, strong, light, and soft; cashmere garments provide excellent insulation, and the material drapes elegantly over the body.
For men’s suits, cashmere is usually blended with sheep wool in proportions that can vary from 1% to 99%. The increased softness becomes noticeable at about 10% cashmere and is a definite asset at 20% and above – though the fabric will be weaker and less durable. At 40% cashmere, the sheep wool’s contribution to the blend starts to fall off and you might as well spring for 100% worsted cashmere.