Pastel is an art medium in the form of a stick, consisting of pure powdered pigment and a binder. Pastel sticks consist of pure powdered pigment combined with a binder. The exact composition and characteristics of an individual pastel stick depends on the type of pastel and the type and amount of binder used. It also varies by individual manufacturer.
Dry pastels have historically used binders such as gum arabic and gum tragacanth. Methyl cellulose was introduced as a binder in the twentieth century. Often a chalk or gypsum component is present. They are available in varying degrees of hardness, the softer varieties being wrapped in paper. Some pastel brands use pumice in the binder to abrade the paper and create more tooth.