C20H6Br4Na2O5 – eosin – is a crystalline powder with a red-yellow color. It is utilized as a dye in multiple industries. It is used in the manufacture of red printing ink, and can also be added to lipsticks and liquid blush to create a bright pink color. It is widely used in microbiology, biology, and medicine to dye bacteria, cells, muscle fibers, and proteins. It stains special white blood cells an intense red color. These white blood cells are actually named after eosin – they are known as eosinophils.