In general oriental & Persian rugs are woven using a cotton foundation and woollen knots. This type of rug construction was widely used throughout the orient.
Silk was used to highlight woollen rugs and give the rugs a greater value. Silk has a far greater tensile strength than wool or cotton hence; old silk rugs are more often in better condition for their age, giving them even greater value.
Silk was also used for the foundation of very fine rugs and Persian silk on silk rugs can have as many as one million knots per sq meter, making the patterns in the field so fine they look like photographs. Needless to say these rugs are extremely valuable and can fetch huge sums of money when sold.
Tribal rugs can be made from camel hair, but a buyer can be fooled into purchasing a Hamadan or some Kurdish rugs that are actually wool, dyed with walnut husks.
In my next entry, I will explain the virtues of different types of wools etc and how this can affect the value of some rugs.