As everybody knows, cotton is a natural fiber extracted from the plant of the cotton. If you manufacture this natural fiber by spinning, you will obtain cotton yarn that can be transformed in the textile you want.
The fiber is more often spun into yarn or thread and used to make a soft breathable textile.
In underwear items we prefer lighter fiber, manufactured in Jersey, or ribbed embellished with a little percentage of Polyamide which will give elasticity because cotton is a 100% stiff fabric.
Wool is a natural fiber made from the manufacturing of the hair of the mantle, fleece, obtained by shearing a particular kind of sheep bred for this purpose. This fiber is well know its insulation.
Wool, after it is washed, cleaned and defatted, has a tint that is from ivory to white. It has a still structure and is warm to the touch thanks to the air among the fiber.
100% wool as almost disappeared from the market because it could harm skin so it is often commercialized blended with other more or less precious fiber (from satin to Polyester) which give it more steadiness during the washing-up and more comfort.
Silk is the most precious and light natural fiber that we can get. It is composed mainly of fibroin and is produced by certain insect larvae to form coccons.
The silk production reached its maximum development in Europe. It became one of the most important goods for international market when the demand for silk items increased until it started to be produced in the textile industry.
This production reached Italy, too but it has not increased because of the discovery and employment of cheaper synthetic fibers.
Its features of softness, brilliance and pleasant feel permit silk, even if it is expensive, to be see sought for the production of high quality textile and often is blended with wool and other synthetic fiber to get better quality.