Wool is a natural textile fibre obtained from the fleece of sheep (sheep and some types of goats), rabbits and camelids (camels, llamas, vicuñas, alpacas). The product obtained from the shearing of these animals is called virgin wool.
The fibre, made up of a protein substance, keratin, has a length between 2 and 90 mm, has a circular section and is externally lined with scales. This particular fibre also has numerous elastic undulations, which gives the wool softness, elasticity, hygroscopic properties and dry thermal resistance, due to the air retained between the fibres.
Resistance to mechanical stress is poor.
Compared to other textile fibres, wool has very low tenacity (1.2-1.7 g / den), good elongation (30-50%), high hygroscopic properties and excellent resistance to mould and bacteria, but it can be attacked by moths.