I’ve been looking at a lot of local limestone and sandstone lately. Sandstone is made of sand, often in tiny annual layers. But limestone is made of the remains of tiny sea creatures. To be specific, much of it is formed by coccolithophores, which are distinguished by an ‘armour’ of tiny plates of calcium carbonate. Trillions of their skeletons formed the basis of some of the world’s most interesting landscapes.
They still dump 1.5 billion kg of calcite into the ocean every year.