Crystal structure of calcite<unk>  is a chemical compound with the formula<unk> . It is a common substance found in rocks as the minerals calcite and aragonite (most notably as limestone, which is a type of sedimentary rock consisting mainly of calcite) and is the main component of eggshells, gastropod shells, shellfish skeletons and pearls.<unk>  is the active ingredient in agricultural lime and is created when<unk>  ions in hard water react with<unk>  ions to create limescale. It has medical use as a<unk>  supplement or as an antacid, but excessive consumption can be hazardous and cause hypercalcemia and digestive issues.
Calcium carbonate
Strontium ranelate
Potassium fluoride
Sodium fluoride
Lanthanum carbonate
Aluminum chloride hexahydrate
Calcium fructoborate
Magnesium citrate