Staple textile fibers are shorter fibers that are measured in inches. As a general rule, all natural fibers are staple length. To give you an idea of their size, here are a few natural fiber lengths: cotton = ½” - 2 ½”, flax = 2” - 26”, and wool is about 1” - 18” long. But, there are a few exceptions to this rule. They are silk, metal, and rubber.