Magnesium carbonate, also known as the mineral magnesite when found in nature, is a chemical compound with a variety of uses. It is a white, odorless, low density compound, with chemical formula: MgCO3. The chemical is used to make magnesium oxide. Magnesium carbonate is added to table salt to prevent caking and used in gymnastics, weightlifting, and climbing to absorb sweat providing better grip. It is also used, with calcium carbonate, in some antacid tablets.