Vintage Silk Foundation Isfahan Persian Rug The Iranian city of Isfahan has long been one of the centres for production of the famous Persian carpet (or rug). Isfahani carpets are renowned for their high quality. Isfahan rugs are knotted on either silk or cotton foundations, with up to 1.000.000 Persian knots/sqm(there have been pieces created by Seirafian master workshop with higher knot count), using exceptionally good quality (referred to as kork wool in Iran) wool for the pile, which is normally clipped quite low.