The primary ingredient of viscose is wood pulp, but this organic ingredient goes through a lengthy production process before it becomes a wearable fabric. Therefore it is neither truly natural (like cotton, wool or silk) nor truly synthetic (like nylon or polyester) – it falls somewhere in between.
In more detail: Viscose is made of Rayon. Rayon is an artificial fiber made from cellulose, derived from wood pulp, cotton or other vegetable materials. Rayon is processed into fibers in a variety of ways, the process itself providing for the name of the material. The two most common production methods for rayon are the cupro-ammonium process and the viscose process. Modal and Tencel (brand names) or Lyocell as it is also called are made of rayon. Rayon absorbs well and is very suitable for dyeing and coloring.