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Definition of PERIDOTITE
: any of a group of granular igneous rocks composed of ferromagnesian minerals and especially olivine
Origin of PERIDOTITE
French péridotite, from péridot
First Known Use: 1878
Coarse-grained, heavy, igneous rock that contains at least 10% olivine, other iron- and magnesium-rich minerals (generally pyroxenes), and not more than 10% feldspar. Peridotite is the ultimate source of all chromium ore and naturally occurring diamonds, and of nearly all chrysotile asbestos. Nearly all peridotite is more or less altered to serpentine; in warm, humid climates peridotite and serpentine have weathered to soils and related deposits that, though now worked on a relatively small scale, are potential sources of iron, nickel, cobalt, and chromium.