What is Calcium carbonate?
[[Image:Calcium carbonate.jpg|thumb|Calcium carbonate]] '''Calcium carbonate''' is a [[chemical compound]], with the [[chemical formula]] [[Calcium|Ca]][[Carbon|C]][[Oxygen|O]]<sub>3</sub>. The elements involved are calcium (Ca), carbon (C) and oxygen (O). It is a common substance found as [[Rock (geology)|rock]] in all parts of the world, and is the main component of [[Animal_shell#Seashells|seashells]], [[snail]]s, and [[Egg (biology)|eggshell]]. Calcium carbonate is usually the main cause of [[hard water]]. It is used as a [[calcium]] supplement or as a treatment for [[antacid]] (brand name Tums), but too much can be bad for your health. Calcium carbonate is found naturally as the following [[mineral]]s and rocks: * [[Aragonite]] * [[Calcite]] * [[Vaterite]] or (μ-CaCO<sub>3</sub>) * [[Chalk]] * [[Limestone]] * [[Marble]] * [[Travertine]] To test whether a mineral or rock contains calcium carbonate, strong acids, such as [[hydrochloric acid]], can be added to it. If the sample does contain calcium carbonate, it will fizz and produce carbon dioxide. Weak acids such as acetic acid will react, but less quickly. All of the rocks/minerals mentioned above will react with acid. ==Related pages== [[Image:CanarySpring.jpg|thumb|Travertine calcium carbonate deposits from a hot spring]] * [[Aragonite]] * [[Calcite]] * [[Limestone]] * [[Ocean acidification]] * [[Gesso]] * [[Cuttlefish]] * [[Cuttlebone]] {{chem-stub}} [[Category:Minerals]] [[Category:Geochemistry]] [[Category:Calcium compounds]] [[Category:Carbonates]]