Olivine is any of a group of silicate minerals which are orthosilicates of magnesium and iron (Mg, Fe)2SiO4.
Olivine forms olive-green crystals in the orthorhombic system, and occurs
commonly in igneous rock, chiefly basalt, gabbro, and peridotite.
The transparent variety peridot is used
as a gemstone. Olivine is also found in
some meteorites, such as carbonaceous chondrites.
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