Marble is metamorphosed rock comprised of limestone formed from calcite under heat and pressure from the earth over millions of years. Since ancient times, it has been used as a building material because of its beauty and durability. In fact, portions of Greek temples dating to 1000 B.C., still stand, including the Temple of Apollo at Delphi, Greece (left).
Today, architects and designers use marble, limestone and travertine not only for exteriors, but also to enhance interior flooring, walls, countertops and other elements in fine homes and commercial buildings. The purest calcite is white marble; other colors contain other minerals, such as limonite in yellow marble.