The coat of a sheep and the original staple fibre used in the manufacture of carpet. Since wool is a natural fiber, it ranges in colour from off-white to black, with a number of earthen tones between. Although wool doesn't stand up to abrasion and moisture as well as synthetics, it cleans well and is known to age gracefully. Wool is the most expensive carpet fibre and represents less than one percent of today's U. S. Market.