The color of crude oil ranges from dark to light, mainly brown-black, brown-black, gray-black, black-brown, and black-brown; also gray-green, red-brown, light yellow, light yellow-green, colorless and transparent. It is mainly related to the chemical composition and content of pigments, non-hydrocarbons and asphaltenes in crude oil. In general, the higher the non-hydrocarbon and asphaltene content, the darker the crude oil.
Usually, crude oil is mostly black, commonly known as “black gold” and “industrial blood.