earth colors
Pigments manufactured by refining naturally
colored clays, rocks, and earth, and also the pure
iron oxide reds, such as Indian red light red,
etc. The iron oxides, although artificial
counterparts, are classified with the native red
earths. Earth colors are also classified as
mineral pigments, along with the manufactured
inorganic pigments. They are characterized by good
light and heat fastness. (233 , 306 )