What Is Carbonate Rock?

Limestone

• Limestones are the most common of the carbonate rocks. However, the term "limestone" does not describe a single rock. Rather, "limestone" describes a grouping of similar carbonate rocks all composed of CaCO3 and reacting with dilute HCl acid. Limestone is soluble in water and weak acid solutions. It takes some time for limestone to dissolve in water, but it will eventually breakdown. Most underground cave systems have been carved by water eating away over hundreds of years at limestone.

Marble

• Marble is considered a metamorphic type of carbonic rock that mainly consists of recrystallized calcite from limestone. It is used as a building material and in artwork. The crystals in marble are small and it can range in color from white to black. Marble contains no fossils and was mostly formed ages ago underneath the Earth's crust under extreme heat temperatures. Like limestone, marble easily dissolves in acidic fluids.

Dolomite

• Dolomite is a type of carbonate rock that is found mainly in ancient rock formations, such as mountains. It is usually found in massive beds along the surface of the Earth that can be hundreds of feet thick. This rock is named after the French mineralogist that discovered its existence, Deodat de Dolomieu.

Fossils

• Limestone and other carbonate rocks often contain fossil particles. Pieces of carbonate rocks have been found with fossilized impressions of ammonites along their surfaces. Ammonites are an extinct group of marine invertebrate.