Wool is a natural fiber that consists of hair from animals such as sheep, goats, llamas, alpacas, camels, rabbits or other animals. Like our own, human hair, wool fibers have ”shells”, which can hold both air and water, and that is exactly what makes wool unique! Wool fibers are also frizzy and thus elastic.
The degree of softness of wool depends, among other things, on the thickness of the fiber and how scaly / effervescent the fiber is.
Merino wool comes from a breed of sheep called Merino and they originated in Spain. Merino wool has thinner and smoother fibers then, for example, wool from Swedish or Nordic sheep. This makes the merino wool feel soft and comfortable and can be used directly against the skin, unlike the Nordic wool which has a coarser surface and fiber which is better suited for thick wool sweaters than close-fitting underwear.