Optical microscope image of rayon fibers. Rayon is a manufactured regenerated cellulose fiber. Rayon is produced from naturally occurring polymers and therefore it is not a truly synthetic fiber, nor is it a natural fiber. It is known by the names viscose rayon and art silk in the textile industry. The identification of different types of fibers is critical to investigating a crime scene. The magnification is 200 times when printed 10 inches wide.