The Yazd rugs have asymmetrical ( Persian ) knots with three wefts. The number of knots in square inch is much lower than Isfahan rugs and Nain rugs, but the pile is softer and longer. The quality of the wool which is from the local is fine and the natural dye makes the rug look lustrous. In the desert surrounding the city of Yazd,madder is cultivated and its root is used for different shades of deep and light red.