Calcium carbonate is a white, odorless powder or colorless crystals , practically insoluble in water, occurs extensive in rocks world-wide. Ground calcium carbonate results directly from the mining of limestone. The extraction process keeps the carbonate very close to its original state of purity and delivers a fine ground product either in dry or slurry form. Precipitated calcium carbonate (CAS: 471-34-1) is produced industrially by the decomposition of limestone to calcium oxide followed by subsequent recarbonization or as a by-product of the solvay process (which is used to make sodium carbonate). Precipitated calcium carbonate is purer than ground calcium carbonate and has different (and tailorable) handling properties.