The word marble derives from the Greek marmaros, "shining stone".
Marble is a metamorphic rock resulting from the metamorphism of limestone, composed mostly of calcite. It is extensively used for sculpture, as a building material, and in many tile applications.
The metamorphic process causes a complete re-crystallization of the original rock into an interlocking mosaic of calcite and/or dolomite crystals. The high temperatures and intense pressures necessary to form marble usually destroy any fossils and sedimentary textures present in the original rock.
Pure white marble is the result of metamorphism of very pure limestone. The characteristic swirls and veins of many colored marble varieties are usually due to various mineral impurities such as clay, silt, sand, iron oxides, or chert which were originally present as grains or layers in the limestone. Green coloration is often due to serpentine resulting from originally high magnesium limestone with silica impurities.
Colorless marbles are a very pure source of calcium carbonate, which is used in a wide variety of industries. Finely ground marble powder is a component in paints, toothpaste, plastics, and used in many other trades.