Gaspra Black Henna are henna based hair dyes which are packed in powder form and are ready to use with just addition of water. Gaspra Black Henna’s main ingredient is natural henna powder. This natural henna powder also known as mehndi, is very nurturing for hair. Usage of Black Henna: Before using Natural Black henna hair color, clean the hair with shampoo or soap and dry it. Mix the henna hair color powder in water and form a paste. Immediately apply the paste and keep it on hair for 30 minutes, afterward wash the hair with water.