Centuries of selection for wool qualities are reflected in today's extraordinary range of fleece types, textures, and colors. Long wool fleeces are loose and open, and they hang in locks. The fibers grow up to twelve inches per year and have a sheen and strength that is imparted to finished products. At the opposite end of the spectrum are the fine wool breeds that produce tightly crimped fibers of very small diameter. These wools are prized for the manufacture of soft, delicate garments.
Medium wool falls between long wool and fine wool, and it is useful for many different purposes.
In North America, however, most medium wool breeds have been selected for meat production rather than wool quality, so that relatively few of them produce anything other than generic, white wool that is blended in large lots for processing. Carpet wool breeds are double coated, with a coarse, long outer coat for protection from rain, snow, and dust, and a medium to fine inner coat that provides insulation. This type of fleece is unsurpassed for the manufacture of rugs because of its durability. Carpet wool breeds are generally adapted to extreme environments, and the characteristics of the wool are part of that adaptation. They lack wool altogether and are covered instead by short hair that is shed annually.