Indigo dye is an organic compound with a distinctive blue color. Indigo is a natural dye obtained from the leaves of some plants of the Indigofera genus, in particular Indigofera tinctoria. Dye-bearing Indigofera plants were once common throughout the world. It is now produced via chemical routes. Blue colorants are rare. Since indigo is insoluble, it is also referred to as a pigment.