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 peridotite A dark, course-grained igneous rock composed mainly of olivine with some pyroxene and hornblende but little feldspar; it alters to serpentine. Some varieties of peridotite bear chromium ore, platinum, or diamonds. Rocks that consist mainly of olivine are called dunites. 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