Sidewalk chalk are typically large colored (and sometimes white or cream) sticks of
chalk (
calcium sulfate rather than rock
chalk, calcium carbonate) mostly used for
drawing on
pavement or
cement sidewalk. It is sometimes used by children to draw a
four square court or a
hopscotch board.
Blackboard chalk is typically shorter and white.
There are several different types of sidewalk chalk, typically coming in solid-colored sticks. 3-D sidewalk chalk sets, in which each stick of chalk is created with two particular colors that appear
3-dimensional when viewed through the 3-D glasses that come with the chalk, also exist.
Sidewalk chalk can be cheaply homemade.