Crude oil is usually black or dark brown, but can also be yellowish, reddish, tan, or even greenish. Variations in color indicate the distinct chemical compositions of different supplies of crude oil. Petroleum that has few metals or sulfur, for instance, tends to be lighter (sometimes nearly clear). Petroleum is used to make gasoline, an important product in our everyday lives. It is also processed and part of thousands of different items, including tires, refrigerators, life jackets, and anesthetics.
