Nylon yarn is a synthetic material yarn that can be made to resemble the look and feel of many natural fibers. Originally, nylon was created as a substitute for silk when the latter material became difficult to obtain. Nylon is strong, slightly stretchy, and generally cheaper than natural fiber yarns. This makes nylon good for many types of knitting projects. It is also usually easy to work with, so it may be a good material choice for beginner knitters. http://www.seagorcare.com/nylon-yarn/