The majority of cosmetics use raw materials that are not compatible so a cream or emulsion is used. Emulsions are pseudo stable mixtures of immiscible liquids dispersed in another liquid. They are used for products like hand moisturizers, make up, hair conditioners, sunscreens, etc. To create them you need three formula components including an oil phase, aqueous phase, and an emulsifier. The formulas are made by heating up the oil and water phases separately, mixing them together (along with the emulsifier) when they are hot, and cooling them down with thorough mixing. The result is a cream with tiny particles of dispersed in the diluent phase. See our article on emulsion HLB for more information on creating emulsions.