Silicones (an emollient and texture enhancer) are a group of synthetic compounds made of silicium, an element which is (after oxygen) the most present in the crust of the earth. It’s extracted from sand and undergoes a chemical reaction to obtain a polymer (liquid, solid or gel). In cosmetics they are used to lock moisture in the skin, but they can be too occlusive. They also create a silky and smooth texture and make the hair and skin shiny. 

Silicones are also used in adhesives, coatings, electronics and kitchen utensils. According to Plastic Soup Foundation, silicones can be classified as microplastics, because it’s a polymer and non-biodegradable. But because silicones are often liquid or gel, European law does not recognize them as microplastics (yet!).