GEOLOGY & PLANETARY SCIENCE A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site marble Marble. Credit: Mineral Information Institute A metamorphic rock, composed chiefly of calcium carbonate (CaCO3). Marble is formed by the metamorphism of limestone and is often irregularly colored by impurities. It is used for architectural and ornamental purposes. Related category    • GEOLOGY AND PLANETARY SCIENCE Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP