Marble has been the preferred material for stone monumental sculpture since ancient times, with several advantages over its more common geological "parent" limestone, in particular the ability to absorb light a small distance into the surface before refracting it in subsurface scattering. This gives an attractive soft appearance that is especially good for representing human skin, which can also be polished.
Of the many different types of marble the pure white ones are generally used for sculpture, with coloured ones preferred for many architectural and decorative uses. The degree of hardness is right to carve without too much difficulty, but still give a very durable result, if not exposed to acid rain or seawater.
Famous individual types and quarries include from classical times Parian marble from Paros, used for the Venus de Milo and many other Ancient Greek sculptures, and Pentelic marble, from near Athens, used for most of the Parthenon sculptures, and by the Romans. Carrara marble from northern Italy was used by the Romans, and very extensively up to recent decades, when the pure white statuario grade more or less ran out. This was used by Michelangelo and other Renaissance sculptors, and later exported, including to America.
Marble
Marble is a metamorphic rock derived from limestone, composed mostly of calcite (a crystalline form of calcium carbonate, CaCO3). The original source of the parent limestone is the seabed deposition of calcium carbonate in the form of microscopic animal skeletons or similar materials. Marble is formed when the limestone is transformed by heat and pressure after being overlain by other materials. The finest marbles for sculpture have no or few stains, though natural stains can be incorporated into the work itself.
Among the commonly available stones, only marble has a slight translucency i.e. subsurface scattering that is comparable to that of human skin. It is this translucency that gives a marble sculpture a visual depth beyond its surface and this evokes a certain realism when used for figurative works.