Is there a difference between silk and satin?

Yes, and the difference is bigger than it sounds. Silk is a natural protein fibre. Satin is a weave, usually made from polyester or nylon. Polyester satin feels slippery, while silk is softer with less friction thanks to its charmeuse weave. Silk also regulates temperature, is hypoallergenic, and resists mould, mildew and dust mites.