A super common, waxy, white, solid stuff that helps water and oil to mix together and leaves the skin feeling soft and smooth.
It can be produced from most vegetable oils in a pretty simple, "green" process that is similar to soap making. It's readily biodegradable.
It also occurs naturally in our body and is used as a food additive. As cosmetic chemist Colins writes it, "its safety really is beyond any doubt".