Colored Drawing Chalk produces strong, brilliant colors for artwork on paper and surfaces other than chalkboards, such as construction paper, cardboard, paper bags and craft paper. Chalk delivers a smooth laydown as it glides onto these surfaces. It can be blended directly by applying one color over another or by rubbing with fingers. Chalk is a great craft supply in classrooms and craft rooms. Each nontoxic chalk stick is 3-1\/8" long x 3\/8" in diameter. Drawing Chalk is not designed for chalkboards.