Tabriz is one of the oldest, largest, and most famous carpet-making centres in Iran. The quality of the rugs is measured in terms of Raj which shows the knot density of the carpets. A special style of knotting called Turkish nut is used in weaving Tabriz Rugs, making them more durable and putting them amongst the highest quality handmade Persian rugs. Tabriz carpets are well known for the diversity of colours and designs, which comes from the rich culture of different tribes live in the area. The main colours in Tabriz carpets are red and Blue. However, different colours such as cream, navy, beige, and pink can be found in the design.  Typical motives of Tabriz rugs are central medallion surrounded by flower and floral patterns. Fish (Mahi) design is one of the most famous Tabriz rugs motives and, which is also very popular in western countries. Other popular motives and designs are Gonbad (Dome), Pictoral, Heris, Four Season, and Tree of Life.