The luxurious silk and wool rugs of Qom are known for their high quality and are regarded among the most expensive in the world. Persian Qum rugs are often considered as investment, because their value is constantly increasing. Tree of life and medallion motifs feature heavily in rugs knotted in Qom. Shades are similar to most popular colors of Persian rugs - blue, red and ivory. Qom Rugs are typically smaller than other types of Persian rugs. They are often placed on walls.