It is important to watch out for fake silk or blended silk. Silk is the queen of fabrics, but with that high quality comes a higher price, and so people are always trying to use all sorts of strategies to trick you into buying various kinds of fake silk.
Unfortunately, unlike in life, you can’t fake it till you make it with silk. While you can’t always tell for certain just from an online listing if it’s real silk, there are a few tricks you can use to tell if something is 100 silk pillowcase.