WHERE DOES CHALK COME FROM?

The powdery white stuff used to make blackboard chalk was created way in the salty sea. It was made by mini creatures that have a long fancy name. Scientists call them foraminifera. Zillions of these midgets take chalky minerals dissolved in the sea water and used them to build tiny chalky shells. They live and die  and their bitsy shells fall to the bottom.

After long ages, thick carpets of these chalky shells collect on the sea bed. Sometimes this part of the sea lifts up and rises above the waves. Then a layer of chalky rock is left high and dry in the air. This is the material we dig up, sift and grind into powder.

A little gummy material is added, and the mixture is molded to make snowy white blackboard chalk. Sometimes other ingredients are added to make colored sticks of chalk.