One important way to determine the quality of an oriental rug is by studying the compactness of the weave, measured as the number of knots per square inch. More knots per square inch require more labor invested in the rug, which commands a higher price for the rug.

However, knot count is only one factor which affects rug quality. It is not always true that a carpet with fewer knots per square inch is less valuable or of lower quality than a rug with a high knot count. Quality standards differ in different classes of rugs.

Great skill and time is required for intricate patterns, which will also raise the price of the rug. Well made rugs have knot counts that are the same throughout the rug. Regularly spaced, even knots are an indicator of quality, as is a pattern which looks sharp and regular when viewed on the back of the rug.

Wool

Wool used in the pile is available in many grades and affects the finished look, quality and price of the rug. Quality wool is resilient enough to return to its original appearance after being compressed. Many different brands of sheep produce rug wools; each with its own sheen and softness characteristics.

Antiques

An increased demand for antique rugs recently has caused diminishing supplies and, consequently, high prices. With antique and old rugs, place of origin, age, condition, and availability in the market affect the price.

Last but not least, colors and their balance and harmony within the design affect the price of the rug.