Chalk
This is an old revision of this page, as edited by Pachyderm (talk | contribs) at 13:52, June 28, 2007. It may differ significantly from current revision.
Chalk is a white, Sedimentary rock, composed of calcite.
Nowadays, chalk has been replaced by other substances. For example, the "chalk" that is used in blackboard writing or in sidewalk chalk is actually gypsum.