Marble

Marble, rock form of limestone consisting of crystals of calcite or dolomite. Marble is formed when limestone is metamorphosed (changed by great heat and pressure) so that the rock is recrystallized and hardened. Pure marble, which is snow-white in color, has been prized by sculptors and architects since ancient times. Some of the finest marble comes from the Carrara quarries in Italy, and in the United States, from Vermont. Marble often contains impurities, which affect is color. Exposed to acid fumes and water, marble will corrode.