Limestone Limestone is a kind of sedimentary stone that is very common all over the Mediterranean and Europe .
Limestone is made out of the shells of zillions of little tiny sea snails and creatures like that.
These snails and stuff lived in the sea, billions of years ago, and when they died they fell to the bottom of the sea and rotted, but their shells, which were made of calcium like your teeth, did not rot and just stayed there. Pressure from other shells, and from the water, and from sand being washed over the shells, squashed them all together into rock. When limestone gets even more squashed, it can turn into marble . Limestone is also the main way you get lime, which is one of the things you make cement out of. To get lime, you have to burn limestone in lime kilns, and then what is left is lime.