Marble. One of the earliest uses of marble in art was in ancient Greece, where it was used to create sculptures, architectural elements, and decorative objects. The Romans also valued marble for its beauty and durability, and used it extensively in their architecture and sculpture. During the Renaissance, marble became a popular material for sculpture once again, and artists such as Michelangelo and Donatello created some of their most famous works using this material. Marble was also used to create decorative elements for churches and palaces, such as columns, altarpieces, and flooring. In terms of painting, marble was not typically used as a surface for panel paintings. Wood panels were the most common support for paintings during the Renaissance, as they were relatively inexpensive, lightweight, and easy to transport. However, there are some examples of paintings that were created on marble, although these are relatively rare. Marble is a metamorphic rock consisting of carbonate minerals that have recrystallized under the influence of heat and pressure. It has a crystalline texture, and is typically not foliated, although there are exceptions. In geology, the term marble refers to metamorphosed limestone, but its use in stonemasonry more broadly encompasses unmetamorphosed limestone. Marble is commonly used for sculpture and as a building material. The Marble Boat, a lakeside pavilion in the Summer Palace in Beijing, China The word marble derives from the Ancient Greek, from, crystalline rock, shining stone, perhaps from the verb, to flash, sparkle, gleam; Beekes has suggested that a Pre-Greek origin is probable. This stem is also the ancestor of the English wordmarmoreal, meaning marble-like. While the English term marble resembles the French, most other European languages more closely resemble the original Ancient Greek. The Taj Mahal is clad entirely in marble. Folded and weathered marble at General Carrera Lake, Chile Marble is a rock resulting from metamorphism of sedimentary carbonate rocks, most commonly limestone or dolomite. Metamorphism causes variable recrystallization of the original carbonate mineral grains. The resulting marble rock is typically composed of an interlocking mosaic of carbonate crystals. Primary sedimentary textures and structures of the original carbonate rock have typically been modified or destroyed. Pure white marble is the result of metamorphism of a very pure limestone or dolomite protolith. The characteristic swirls and veins of many colored marble varieties, sometimes called striations, 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 magnesium-rich limestone or dolomite with silica impurities. These various impurities have been mobilized and recrystallized by the intense pressure and heat of the metamorphism. Outdoor marble statues, gravestones, or other marble structures are damaged by acid rain whether by carbonation, sulfation or the formation of black-crust. Vinegar and other acidic solutions should be avoided in the cleaning of marble products. Crystallization refers to a method of imparting a glossy, more durable finish on to a marble floor. It involves polishing the surface with an acidic solution and a steel wool pad on a flooring machine. The chemical reaction below shows a typical process using magnesium fluorosilicate and hydrochloric acid taking place.