Identifying Antique Persian Rugs

Measure the rug. Size matters in the identification of an antique Persian rug. According to Stanley Reed, rug expert and author of "All Color Book of Oriental Carpets and Rugs," antique Persian rugs typically measure 9 by 6 feet or smaller. Larger pieces are considered carpets, not rugs.

Look at the fabric foundation of the rug to determine if it is woven of hand-spun natural fibers. The base or mesh of an antique Persian rug -- to which the individual knots are tied to make the design -- is called the foundation. Antique Persian rugs always either start with a woolen or, more commonly, a cotton foundation. These rugs began to be made in the sixth century B.C. As early as the late 1500s, they started showing up in European castles and homes. If there are any synthetic fibers in your rug, it cannot be identified as an antique Persian rug.

Examine the fibers used in the individual knots that make up the design of the rug, using the magnifying glass. In an antique Persian rug, these knots are made with either all woolen or all silk threads, which have been dyed with natural materials. Rub the fibers in the knots of the rug to see if they get warmer. If they do, the fibers are probably wool or silk. If the temperature in the knots does not seem to change, the rug is probably made of a synthetic lookalike fabric. This is not the most accurate test but it is the only practical one for laymen. Experts can be hired to perform a chemical test to absolutely identify whether the fibers are natural or synthetic. Another way to tell whether the fibers are natural is to burn one. Both wool and silk are protein based fibers so they will smell like burning hair when ignited while burning synthetic fibers produces a smell like burning paper. However, it is unlikely that you will elect to burn fibers from a rug that may be an antique Persian rug.

Determine what kind of knots were used in the rug. Two types of knots are found in antique Persian rugs: The Persian knot, which is a half knot; and the Turkish or Ghiordes knot, which is a full knot. To make a half knot the weaver inserts a thread behind one warp string, above and around the next warp string so that one end of the thread comes up from between the two warp strings and the other end comes up to the left or the right one of the warp strings. This differs from a full knot in which the weaver inserts both ends of the thread on top of two warp strings and pulls each end up through the middle of the two. The knots leave the threads hanging so that they can be shaved when the rug is finished to make the pile.

Count how many knots the rug contains per square inch. There can be be more than 1,000 knots per square inch of rug when they are made with silk threads, for example. The more knots per square inch in an antique Persian rug, the longer it took to make -- thus, the more money that rug is worth.

Observe the types of images in the rug's design. Curved lines are commonly found in antique Persian rugs. Dragons, birds, animals fighting, hunting, leaves, vines and floral arrangements are all typical subjects in these rugs. An expert will know whether your rug was made by a particular tribe or in a certain city like Isfahan, Kashan, Tabriz or Herat by examining the rug's design.

Appeal to a textile conservator or other expert in antique Persian rugs to authenticate your rug. This person will use sophisticated equipment like an optical or electron microscope to determine more precisely when, where, and by whom the rug was made. The expert will also be able to provide you with a good estimate of the value of the rug, either for insurance purposes or for resale.