Van Gogh Oil pastels contain a binder of mineral oils and waxes. They are available in a wide variety of colors. Each color sold seperately in a three-inch stick.
The last number in the color code indicates the tone of the pastel. Color swatches also reflect these differences in tone.
.3 = mixing shade with black
.5 = full shade
.7/.8/.9 = mixing shade with an increasing amount of white