Ask the rug distributor for the name of the rug. Most Persian rugs made in Iran are named from the town, village or district where they were weaved. Look up the name that is given to find out if the name matches with a region in Iran. Check out the link in resources for helping you identify the rug.
Examine the design of the rug. Different regions of Iran have their own signature design. For example, Tabriz rugs incorporate curves into their patterns and use vibrant colors. Baluch rugs generally use burgundy in their color scheme. They employ prayer rug designs or simple patterns.
Flip the rug over and look at the knots on the back of the rug. Most Persian rugs are made to have asymmetrical knots, which means they are not perfect if a line was drawn through the middle. In addition, they are usually very compact and packed down. Tabriz is one of the few Persian rugs made with a symmetrical knot.
Measure one square inch of the rug with measuring tape. Count the number of knots in a square inch. If there are less than 150 knots, the rug has a good chance of not being Persian.
Fold the rug to see how it folds. Rugs that fold over like stiff napkins are typically Persian. If the rug easily folds over, it is probably not a Persian but a replica of one.