Iron oxides are inorganic compounds of iron and oxygen that have been used as coloring agents in cosmetics since the early 1900s. Iron oxides occur naturally, for example, rust is a type of iron oxide. However, the iron oxides used in cosmetics are synthetic. Iron oxides are available as three basic shades: black, yellow, and red. There are also various shades of brown iron oxides, but these are just mixtures of the three previously mentioned colors. If a cosmetic product has the name “CI 77499” on the ingredient list, this means that black iron oxide is used in that product.
Iron oxides are the main pigments used for matching skin tones in foundations, powders, concealers, and other makeup for the face. Iron oxides can also be found in eye shadows, blushes, powders, lipstick, and mineral makeup. Iron oxides are opaque and have excellent light stability, however, black iron oxides are sensitive to high temperatures. Iron oxides are also resistant to moisture, so they will not easily bleed or smear. Iron oxides have excellent “staying power”, which means that the product will last for a long time without needing to be reapplied.