Indigo powder is a natural dye which is very famous now days for coloring hair black. Many people know it as black henna, but it gives a blue dye. When used with natural henna powder it gives a dark brown to shiny black color. Generally it gives a blue dye even though it looks just like henna. It is also used to dye clothes and get a denim blue color. In botanical language it is known as indogofera tinctoria. The indigo powder is made using the leaves of indigo plant.