In forensic science, comparative examinations are usually based on the physical or chemical nature of a substance, or both. Lipsticks are composed of waxes, oils, organic dyes and inorganic pigments. Color matching can do identifying the lipstick responsible for leaving a smear. This color analysis may be used to identify the lipstick found at the crime scene. The colors of lipstick are often due to a mixture of several pigment compounds. These pigments can be separated using thin layer chromatography. Depending on the type of pigment, the mobile phase will vary. Lipsticks are soluble in toluene, so toluene serves as the mobile phase. After separation, the chromatogram is complete and illustrates the different pigments that make up a particular color of lipstick.