Calcium Carbonate

One of the world’s most useful and versatile materials.

What is Calcium Carbonate?

Calcium carbonate is one of the most useful and versatile materials known to man. This family of essential minerals comprises more than four percent of the earth’s crust and is found worldwide. It is produced by the sedimentation of the shells of small fossilized snails, shellfish, and coral over millions of years.

The most common forms of calcium carbonate are chalk, limestone, and marble. Although all three varieties are chemically identical, they differ in many aspects, including purity, whiteness, thickness, and homogeneity.

Fun Facts

Eggshells are composed of up to 95 percent calcium carbonate.
Chalk has been used as a writing tool for more than 10,000 years and is a fine, microcrystalline material.
Large deposits of pure white “statuario” marble found in Carrara, Italy, were used by the Michelangelo to create his sculptures.
Stalactite and stalagmite formations in caves are created when water containing calcium carbonate drips, leaving some mineral at the tip of the drip at the roof of the cave and where it falls on the floor.

Where to Find Calcium Carbonate

Uses for Calcium Carbonate

Paper, Plastics, Paints, & Coatings Calcium carbonate is an essential mineral in the paper, plastics, paints, and coatings industries. It is used as a filler and, due to its special white color, as a pigment. In the paper industry it is valued for its brightness and light-scattering characteristics. As a filler it is used to make paper bright and smooth. As an extender, it can represent as much as 30 percent of the weight of paints. Calcium carbonate is also used as a filler in adhesives and sealants.

Personal Health & Food Production Calcium carbonate is widely used as a dietary calcium supplement, antacid, phosphate binder, and as a base material for medicinal tablets. It is also found in products such as baking powder, toothpaste, dry-mix dessert mixes, dough, and wine.

Building Materials & Construction Calcium carbonate is critical to the construction industry, both as a building material (e.g., marble) and as a key ingredient of cement. It contributes to the making of mortar used to bond bricks, concrete blocks, stones, roofing shingles, rubber compounds, and tiles.

Food and Health The human body is not capable of producing its own salt, and humans depend on various sources of salt in food to ensure their necessary daily intake. The U.S. Food and Drug Administration and the American Medical Association guidance for salt for people 14 years or older, with balanced nutrition, is limited to 2,300 milligrams per day. Salt is also used as a food preservative. Additionally, it is used by the pharmaceutical industry in a variety of applications including intravenous saline solutions and drug manufacturing.

Agriculture & Water Treatment Calcium carbonate is the active ingredient in agricultural lime, used to reduce the acidity of soils. It is also used in many animal feeds. Calcium carbonate also benefits the environment through water and waste treatment.

Related Resources

USGS Calcium Carbonate Mineral Commodity Summary

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