The materials used most often in Oriental rugs are wool and cotton. Other common materials include goat’s hair, camel’s hair, and silk.
Materials Making up Fibers
Protein – (animal or insect) – There are a few that are used very often such as alpaca, angora, goat hair, camel hair, cashmere, cow hair, horsehair, fur, mohair, rabbit hair, silk, vicuna, etc.
The materials used in genuine oriental rugs are chiefly wool or silk, knotted onto a cotton foundation.
Wool – Wool is naturally flame retardant, is difficult to ignite, has a low flame spread and low heat release properties. Burning wool releases low levels of toxic fumes and smoke.
A lit cigarette dropped on a wool rug will form a slight char mark, which can be easily rubbed off the rug’s surface, leaving no permanent marking.
Live Wool – is sheared from living sheep. It is durable, soft and retains its lanolin, giving the fibers and yarns resilience.
Dead Wool – taken from slaughtered animals by chemicals, is dry, brittle, and abrasive. Such wool does not wear well and has little resilience
Silk – Silk is a two-part protein fiber consisting of fibroin and sericin. It is produced by reeling the cocoons of silkworms, which feed on the leaves of Mulberry trees.
Some threads are said is to be 4000 feet (1.22 km) long.
Other “hair” fibers – hair fiber, especially camel’s hair have central canals that are different from other wool fibers. As a rule, hair fibers are stiffer and wirier than other wool, and they do not felt as easily. Alkali attack hair fibers as quickly as they do other wool fibers, but dilute acids do not injure hair fibers.
Camel – Camel hair is a specialty fiber that sometimes is blended with wool.
Underhair is best since it is lightweight, lustrous and soft. Natural colors include light tan to brownish-black.
Alpaca – A member of the camel family that is native to the high Andean regions of southern Ecuador, Peru, Bolivia, and Argentina
Hides and Leather – A hide or skin that has been tanned into a non-perishable material, either with or without the hair removed.
This information is borrowed from the Rug Cleaning Technician Course.