Essential oils are volatile, fragrant liquids extracted from plant leaves, bark, wood, stems, flowers, seeds, buds, roots, resins and petals, usually through steam distillation. In other words, they are raw materials that can be used to create perfumes. They are highly concentrated and apart from a few exceptions, should not be used directly on the skin, although they can be diluted in a carrier oil, such as jojoba, for such use. Perfume oils are fragrance components, natural or synthetic, in an oily base rather than an alcohol base, and can be used directly on the skin.