Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals.

As the concentration of carbonate increases, calcium carbonate precipitates as the salt Ca2 CO32 CaCO3.

Upon exposure to air, it forms a solid carbonate salt with carbon dioxide.

This is the case for , which is reduced by photosynthesis of plants, and which, after dissolving in the oceans, reacts to form carbonic acid and bicarbonate and carbonate ions (see ocean acidification).

There is tremendous amounts of hydrogen sulfide coming into this cave from volcanic sources and from the breakdown of evaporite minerals below the carbonates in which this cave is formed and it is a completely hostile environment for us.

When water that contains dissolved calcium carbonate is warmed, CO2 is removed from the water as gas causing the equilibrium of bicarbonate and carbonate to shift to the right, increasing the concentration of dissolved carbonate.

Similarly, it is also used in the maintaining reef aquaria, where it is commonly used in calcium reactors to temporarily lower the pH of water being passed over calcium carbonate in order to allow the calcium carbonate to dissolve into the water more freely where it is used by some corals to build their skeleton.