Pile refers to the material (fiber) used for weaving rugs. Only natural fibers are used in handmade rugs. The main pile materials are wool, silk and cotton. Sometimes, goat and camel hair are also used by nomadic and village weavers.
Wool is the most frequently used pile material in handmade rugs because it is soft, durable, easy to work with and not too expensive. This combination of characteristics is not found in other natural fibers. Wool comes from the coat of sheep
Fibers from animals such as goat or camel are considered hair, and even though the use of some hair in rugs adds shine, their extensive use is undesirable because they do not dye well. Moderately coarse wool is more durable than fine wool, and the sheep producing this kind of wool can usually be found in the Middle East. In general, wool from sheep grazing at high altitudes is superior, and very high quality wool can be found at high altitudes of the Caucasian mountains and mountainous areas of Iran. Wool from China, Australia and New Zealand is also very good. Natural wool comes in colors of white, brown, fawn, yellow and gray, which are sometimes used directly without going through a dyeing process.
Silk is an expensive fiber, and therefore, it is less frequently used in handmade rugs. Silk comes from the cocoon of silkworms, which thrive on mulberry leaves. Silk originally came from China and it was then cultivated in countries such as Iran, Turkey, India and some countries of the ex-Soviet Union.
The best quality silk still comes from China and an area of Iran in the south shores of the Caspian Sea. Silk has the two qualities of fineness and strength, hardly found in other natural fibers. Silk can be used alone or in combination with wool. Because of their fineness, pure silk rugs require more care. Therefore, they are generally used as decorative items and hung on walls, or if used as floor coverings, they are placed in rooms with less traffic.