The chalk cliffs on the English South coast are famous, especially the white cliffs of Dover, as they tell English people crossing the Channel by ferry that they are coming home.

Blackboard chalk used to be made of chalk, although now it's made from gypsum. In fact, the derivation of 'gypsum' is a Greek word for chalk, so the two minerals have got muddled in the past.

There is a type of building material called clunch, which is mainly chalk. It is poor quality rock for building, and only used where no other local stone is avilable, such as in certain parts of East Anglia. So chalk cannot really be described as a building stone.

Larger pictures of Chalk: