Both Rugs we have for this face off are silk on silk and hand knotted. Similarities in these two rugs include more or less a similar design and quality.*
ABOVE AND BELOW: Both Rugs have very similar knot count within the 300 range.
But what is it that differentiates these rugs? First and foremost, origin: The Ghom carpet was woven in Iran circa 1970, and the Kashmir woven in India Circa 1975.
However, more than simple origin alone, there are other characteristics and technical aspects which make these rugs quite different from one another. Take for example the general design translation to the front of the rugs seen below:
While the kashmir rug actually has slightly more knots per square inch (on average), the Ghom has a much more fluid and optimized design execution. Pay particularly close attention to the first border on either rug (above and center.) The Kashmir on the right actually has a very simple "zig-zag" design: a highly simplified interpretation as compared to the Ghom silk which has a comparatively ornate design. Also note the differences in the flowers and vines in the second border. The Kashmir knot count is fully capable of demonstrating such detail of the Ghom, however the actual rug is far less intricate.
Above and Below: When we part the pile on each rug, there is an obvious difference in the way which the fibers were spun for weaving. On the Ghom above, there is a slight twist to the silk pile, however it's fairly uniform with a "loose" spin. This is a single ply milled silk. On the Kashmir seen below, each strand of silk is carefully spun with another, rendering a "rope-like" appearance. Each strand is actually a two ply silk. While a double ply has advantages, it is clear the silk used in the Kashmir below implimented a far more "mechanized" form of fiber than that used in the Ghom above.
Above and Below: A comparison between these two rugs regarding thickness. The Kashmir Rug seen below is almost double the thickness of the Ghom above. Many consumers equate more material with more value, however, this is not necessarily the case. What is important to remember is that correct pile height needs to be carefully assessed with the understanding of proper balances in regards to construction. The higher the knot count, the closer to the knot a rug's pile may be cut with little "pixelation". However, these two carpets have similar knot count. What differentiates the optimal pile height for these rugs is the actual fiber itself. Again, the Ghom carpet had a very loosely spun silk, which means it "blooms" or opens up sooner. If the Ghom had twice as tall a pile height, the design would appear much more muddled and less defined. However, because the Kashmir rug has a tightly spun double ply thread, the fiber has the support to stand taller with less "blooming". Therefore, in this example, the Kashmir rug's fiber actually allows for a thicker, fuller pile.
kilim / Fringe:
Above: Note the Ghom rug has a woven Kilim, which immediately underneath is finished with a red and yellow banding. It's not uncommon for these Persian Rugs to have other ornate and decorative details which would not be seen in other weavings from China or India. Above on the right, note where the fringe disappears into the Kashmir rug. Instead of flowing directly into the carpet, there is a short skirt which has been woven before the pile actually picks up. It's not so easy to see with this photograph, however if you look closesly, you can see the "knots" do not actually begin for a 1/2" or so. This flatwoven area is not uncommon to find on many Indian Rugs, however rarely, if at all, found on true Ghom silks.
The Ghom rug as shown was approximately twice the investment of the Kashmir. Keep in mind, these are much older examples from around the time where India was just about to "take on" Persian production before embargo. No one of these rugs is a "better rug," however, it is safe to say that each has their own specific attributes which may or may not be desirable to some. Again, there have been considerable changes to each of these types of weavings since these carpets particular carpets had been woven.