The finest grade of hand-spun wool, clipped from the neck and shoulders of a lamb's first shearing. Long, elastic and unusually rich in lanolin, kork takes dye with exceptional depth and gives rugs from workshops such as Kashan a distinctive silky handle. The presence of kork wool is one of the quiet markers separating a fine city rug from an ordinary one.
The natural wax that coats wool fibers, secreted by the sheep to waterproof its fleece. In a wool carpet, residual lanolin acts as a built-in stain repellent: spills bead on the surface for a few moments instead of soaking in, which is one reason wool rugs forgive accidents that would permanently mark most synthetics. Repeated harsh chemical cleaning strips lanolin away, which is why gentle washing is recommended for wool.