A description of the Wool used in the Construction of Antique Rugs
Most handmade antique rugs are created on a large wooden loom with a foundation of warp (north and south) and weft (east and west) threads often of cotton through which wool threads are knotted to create the pile of the rug. The wool sheared from sheep is spun and soaked in natural dyes made largely from insects, plants and water. The color concentration could vary slightly between dye lots which would sometimes result in a bit of a color change or abrash in a rug. This is normal.
There are many ways to distinguish where a rug was woven. One way is to identify the wool characteristics and how fine the yarn is which will also impact the type of foundation material used. The thicker wool from a rug woven near a mountain region would have a denser pile and a simpler perhaps geometric design. These rugs such as Bidjar rugs are woven on a stronger wool foundation.

Rugs woven nearer the cities may have a more finely spun wool which will allow for more complex designs such as vines and flowers or complex scenes often including bucolic or energetic scenes with animals and people such as is seen in Laver Kerman Rugs.
Beautifully spun very soft wool was also imported from Manchester, England. It is sheared from Merino sheep. These are some of the finest rugs made with the nicest, very finely spun soft wool. This wool was often used for fine Kashan rugs with beautiful fine intricate designs. These rugs are very soft underfoot. The Chinese were also known to import this wool and create beautiful designs.
The most expensive of all wool actually comes from a goat. This wool is known as mohair or angora. The pile rugs made using this rug mostly come from Turkey and have long silky feeling pile. It is very lustrous and dyed in pale beautiful colors and often found in Turkish Oushak rugs.
The last natural material used to weave rugs is from the camel. This is hair shed from a camel and is often used undyed and spun with sheeps wool to create a rug with a beautiful brown hue from a material that is readily available without shearing. This wool is often seen in rugs and runners from Serab and Hamadan regions of Persia.