The traditional favorite for area rugs, and the most commonly used natural fiber would have to be wool. It offers a deep, rich look and feel to any rug, and is associated with quality and comfort. Wool is the textile fiber obtained primarily from sheep, but also from other animals. It consists mainly of protein together with a few percent lipids (lanolin). It is naturally renewable and biodegradable.
Wool has several qualities that distinguish it from hair or fur; a few of which would be that it is crimped and elastic. The amount of crimp corresponds to the fineness of the wool fibers. The quality of wool is determined by a number of factors, including: fiber diameter, crimp, yield, color, length, and staple strength (read about what a staple fiber is here). Fiber diameter is the single most important wool characteristic determining quality and price.
Wool has excellent resilience and durability, and is generally thought to have better resistance to pressure/crush than synthetic fibers. It also has excellent color/dye absorption and provides clear beautiful colors.
Wool fibers readily absorb moisture, but they are not hollow. Wool can absorb almost one-third of its weight in water and can absorb sound like many other fabrics. It is generally a creamy white color, although some breeds of sheep produce natural colors. There are area rug manufacturers that have capitalized on this and have begun to produce beautiful rugs, without dyes, using this naturally colored wool.
Wool fibers have microscopic scales that provide a natural resistance to soiling. These scales help to prevent dirt from embedding in the carpet fibers. Wool also has a lower rate of flame spread, a lower rate of heat release, a lower heat of combustion and does not melt or drip like most synthetic fibers. It also forms a char which is insulating and self-extinguishing, and it contributes less to toxic gases and smoke. Because of these factors, wool carpeting, and majority wool blends are the preferred choice of the International Marine Organization for use on ships and ocean going vessels.
This is an excellent demonstration of how wool does not carry a flame, and does not continue to burn after the fire source is removed. It even has a running commentary of the cute voice of a little girl, (albeit somewhat unwanted by her dad).
As mentioned earlier, wool is highly absorbent, which can be beneficial for the home environment. When the air is humid, wool will absorb moisture from the air, and when the air is drier it will in turn release moisture back into the air. Studies have also shown that wool flooring will help to neutralize several common contaminants often present in today's indoor environments.
Global production is about 2 million tonnes per year, of which 60% goes into apparel. The top 3 countries considered to have some of the best wool for the manufacturing of area rugs are:
The history of wool goes back to the beginning of time because of its versatility and many uses. Ancient civilizations quickly found that wool had a number of beneficial uses because of its innate insulating ability it was soon used for clothing. Over time the wool industry developed into a major economic driver of many European countries, right up to modern times when synthetics stole some of the fanfare away.
With the trend towards hard flooring in North America over the last few decades, there has been an equal trend towards area rugs, many of which are made of wool.
In addition to clothing, wool has been used for blankets, saddle blankets, insulation, upholstery and flooring (carpets and area rugs). Wool felt covers piano hammers (photos below), and it is used to absorb odors and provide noise absorption in a number of situations.