Wool is the fibre that comes from sheep, goats and alpacas. The fibre on sheep has two qualities that are different from hair or fur; it looks likes shingles on a roof, and it is crimped looking. How much crimp it has corresponds with how fine the wool fibres will be. Fine wools will have 100 crimps an inch, while coarser wools will only have one or two crimps. Wool is very warm because its fibres do not conduct heat and its crimps trap still air in it. Its strength makes it one fourth stronger than cotton.

The sheep are sheared using mechanical clippers. The wool is then classified as lamb's wool (or first clip), hog wool (from 12 to 14 month old sheep), wether wool (from old sheep), taglocks (discolored wool), and pulled wool (from butchered sheep). Then, the wool is sorted by its crimp, fineness, and length. Any impurities are removed with detergent and alkali. Lastly, the wool is bleached, dyed, oiled to resist processing, and blended.