Peridotite
Pronunciation : Per"i*do*tite
Part of Speech : n.
Etymology : [Cf. F. p?ridotite.] (Min.)
Definition : Defn: An eruptive rock characterized by the presence of chrysolite (peridot). It also usually contains pyroxene, enstatite, chromite, etc. It is often altered to serpentine.
Note: The chief diamond deposits in South Africa occur in a more or less altered peridotite.
Source : Webster's Unabridged Dictionary, 1913