Chalk

The name for white drawing material, it is called Native Chalk, when derived from calcium carbonate or limestone, and Precipitated Chalk, when made from artificial calcium carbonate. Chalks can be used by themselves or mixed with pigments for color and gum binder to make pastels. Source: Ralph Mayer, "A Dictionary of Art Terms and Techniques"; Kimberley Reynolds & Richard Seddon, "Illustrated Dictionary of Art Terms"