Petrolatum, also known as petroleum jelly, is a mineral oil derivative used for its emollient properties in cosmetics. When I first learned this fact, I was on the search for a moisturizer without petrolatum and found it extremely difficult to find. Ninety-five percent of the moisturizers I looked at not only contained the ingredient, but it was the main ingredient listed on the product, no matter if it was an expensive or an inexpensive brand.