Magnesite can be formed via talc carbonate metasomatism of peridotite and other ultramafic rocks. Among the rocks that commonly include peridotite xenoliths are basalt and kimberlite. Types of trap rock include basalt, peridotite, diabase, and gabbro. The rocks contain xenoliths of harzburgite, lherzolite and peridotite. C isotope ratio different from that typical of diamonds from peridotite xenoliths. These blocks of mantle peridotite and the metamorphic eclogites are exposed as ophiolite complexes. Layered intrusions with cumulate peridotite are typically associated with sulfide or chromite ores. Xenoliths of dunite, peridotite and spinel lherzolite in basaltic lava flows are one example. They have their origins in metamorphic alterations of peridotite and pyroxene. Xenoliths of peridotite are common in kimberlite and in some basalt. The word "peridotite" comes from the gemstone peridot, which consists of pale green olivine. The mantle part of the lithosphere consists largely of peridotite. Small pieces of peridotite have even been found in lunar breccias. Both continental and oceanic crust rest on peridotite of the mantle. Host rocks in a mantle keel include harzburgite and lherzolite, two type of peridotite.