1. Flip the rug over
The single most diagnostic thing you can do with a rug is look at the back. A hand-knotted rug shows its pattern almost as clearly on the back as on the front — every knot is individually tied around the warp and weft, and the colour changes follow the same lines on both sides. A machine-made rug has a uniform mechanical grid on the reverse, usually with a latex or glue backing that hides any pattern. A hand-tufted rug has a visible scrim backing glued to the primary weave — the pattern on the back is completely hidden.
If the back shows the pattern clearly, you are almost certainly looking at a hand-knotted rug. That alone puts the piece in a different value bracket from most area rugs.
2. Count the knots
On the back, measure a one-inch-square section and count the knots horizontally and vertically. Multiply the two numbers. That is the knot count per square inch (KPSI). Typical ranges:
- 40–100 KPSI: tribal and village rugs — Kazak, Baluch, Afghan, many Moroccans
- 100–200 KPSI: standard city rugs — Heriz, Hamadan, Yazd, most Turkish city production
- 200–300 KPSI: finer city rugs — Tabriz, Kerman, Kashan
- 300–800+ KPSI: fine Persians — Isfahan, Nain, Qum (silk Qum commonly over 500 KPSI, occasionally 1,000+)
Higher KPSI enables finer detail but is not automatically an indicator of value. A 100 KPSI antique Heriz can be worth more than a 300 KPSI contemporary Tabriz. Density is one factor among five.
3. Look at the knot type
There are two main knot types in handmade rugs:
- Symmetric (Turkish or Ghiordes) knot: both ends of the yarn loop over the warps. Used across Turkey, the Caucasus, and some Persian tribal weavings.
- Asymmetric (Persian or Senneh) knot: one end wraps, the other lies flat. Most fine Persian work, most of India, much of China.
Under a magnifier, the two look different on the back of the rug. The asymmetric knot allows finer detail per knot count because each knot carries a single yarn through a tighter space. Most people do not need to identify this level of detail — but the presence of one or the other narrows the origin significantly.
4. Check the foundation
Look at the warp and weft — the threads the pile is tied around. Cotton foundation is visible as pale off-white thread at the base of each knot and is the most common on Persian and Indian city rugs. Wool foundation (Turkish, tribal, nomadic) has a yellower, more lustrous appearance. Silk foundation is rare, gives the rug a characteristic sheen on the back, and is found on the finest Persian and some Chinese pieces.
The foundation material is one of the clearest origin clues and one of the factors a RICA-certified appraisal formally records.
5. Look at the dyes
Natural dyes and synthetic dyes age differently. Natural dyes (madder red, indigo blue, pomegranate yellow, walnut brown) fade gracefully and produce an effect called abrash — subtle striping in the field where different dye lots appear slightly different in tone. Abrash is a desirable feature, not a flaw.
Synthetic dyes (introduced from the 1860s onward) age more uniformly and can produce harsh shifts — bright pinks that have faded to dirty coral, magentas that have bleached to peach. Early synthetic dye production between roughly 1890 and 1925 was particularly variable; rugs from that window often show unexpected colour shifts today.
What you still cannot determine
Origin to the workshop level, date of manufacture within a decade, and market value. Those require comparative market analysis, documentation review, and physical inspection by a qualified appraiser. The five-factor framework we use — origin, material, age, condition, knot density — is explained in detail in how rug appraisal works.
For a free photo-based preliminary valuation, our what is my rug worth guide walks through how to submit the right photographs. For a defensible written number for insurance, estate, or sale, a formal appraisal is the right next step.