According to a 2009 article in the Los Angeles Times, cashmere is eight times warmer than sheep's wool. It is also significantly lighter if the garment is made of high-quality, 100-percent cashmere.
The best quality cashmere comes from the longest and finest hair closest to the skin of the goat, preferably on the underbelly and neck regions. Fiber lengths range from 0.8 inches for the least expensive cashmere up to 2.5 inches for the most valuable. To be considered genuine cashmere, the diameter of each fiber must be less than 19 microns, with the smaller fibers, which measure approximately 14 microns, reserved for the finer garments.