A Pigment is the powdered coloring agent that is mixed with a binder such as oil, acrylic or gum to make various artists paints, pastels, chalks, and other materials for making artwork.
Until synthetically made pigments and dyes were invented, all pigments were derived directly from nature; leaves, roots, flowers, fruit and stems of plants, insects, shellfish, earth and minerals too.
Originally paint was hand made by the artist themselves or artist's apprentice, they would buy pigments in their raw form and grind them slowly by hand into a powder to then mix with a binder to make paint.
For a list of the most popular artists pigments see: Pigments List, or click on the links below. Pigments can be bought from most large Art Supply Stores. Pigment quality is comparable between paint brands by referring to the paint's ASTM rating.