Artist's Palette is on the face of the Black Mountains and is
noted for having various colors of rock. These colors are caused
by the oxidation of different metals (red, pink and yellow is from
iron salts, green is from decomposing tuff-derived mica, and
manganese produces the purple). Chemical weathering and hydrothermal
alteration are also responsible for the variety of colors displayed
in the Artist Drive Formation and nearby exposures of the Furnace Creek Formation.

from: Wikipedia