Calcium carbonate
Calcium carbonate is a chemical compound, with the chemical formula CaCO3. The elements involved are calcium (Ca), carbon (C) and oxygen (O). It is a common substance found as rock in all parts of the world, and is the main component of seashells, snails, and eggshell.
Calcium carbonate is usually the main cause of hard water. It is used as a calcium supplement or as a treatment for antacid, but too much can be bad for your health.
Calcium carbonate is found naturally as the following minerals and rocks:
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.
Calcium Carbonate Media
Crystal structure of calcite
Crystal Structure of Calcite and Aragonite
Microscopic Calcite and Vaterite
Calcite is the most stable polymorph of calcium carbonate. It is transparent to opaque. A transparent variety called Iceland spar (shown here) was used to create polarized light in the 19th century.
Calcium carbonate chunks from clamshell
500-milligram calcium supplements made from calcium carbonate
Effects of salinity and pH on the maximum calcium ion level before scaling is anticipated at 25 C and 1 mM bicarbonate (e.g. in swimming pools)
