Kashmiri Carpets are very unique as they are always hand knotted. Knots per square inch determine how costly a carpet is. The pile is almost always silk, the warps and wefts are either cotton or silk. Carpets having silk pile and cotton warps and wefts are called cotton-silk carpets and are priced lower on the scale. The knottage is low, maximum being 320 knots per square inch. Carpets with silk pile and silk warps and wefts are called silk on silk carpets and are priced highest on the scale. Knottage is high starting at 500 or more knots per square inch. There have been silk on silk carpets sold with knottage as high as 3000 knots per square inch.