Marble is a rock widely used in buildings, monuments, and sculptures. It consists chiefly of calcite or dolomite, or a combination of these carbonate minerals. Most marble of commercial value was formed in the Paleozoic Era or earlier in Precambrian Time. Marble is found in many countries, including Belgium, France, Greece, India, Italy, Spain, and the United Kingdom. South American nations also have large marble deposits. In the United States, Georgia produces the most marble. Other chief marble-producing states include Alabama, Colorado, Montana, Tennessee, Texas, and Vermont.