Calcium carbonate is an element found around the world. Because of this, there are six common names for the element: calcite, chalk, eggshells, limestone, marble and Tums.
Calcium carbonate can be found in rocks, snails, pearls, and more. Most of it is mined from quarries, and pure sources of calcium carbonate can be extracted and used for foods and pharmaceuticals. It can also be created from calcium oxide. When water is added to calcium oxide, it produces calcium hydroxide. Passing carbon dioxide through calcium hydroxide produces calcium carbonate by means of precipitation, earning it the industry name of precipitated calcium carbonate, or PCC.