Pigment
A fine coloured powder that does not dissolve, mixed into a liquid to make paint or ink.
Also: colourant
A pigment is a solid colouring matter ground to a fine powder. It does not dissolve; the particles are held in place by something sticky, such as oil, gum or acrylic, which glues them to a surface. Pigments come from earths, minerals, plants, animals and, since the 19th century, chemical factories. Ochre, chalk and soot were among the first and were used in cave paintings tens of thousands of years ago. The difference from a dye is that a dye dissolves and soaks into a material, while a pigment sits on it.