Peridot is gem-quality olivine. Its green color is dependent on the iron contents within the structure of the gem. Gem variety of the mineral olivine: found in peridotite rock from theearth’s upper mantle.
Peridot
Peridot crystals are found in meteorites. Most gems are colored by impurities such as iron. Peridot's color is intrinsically yellow-green. Peridot has extremely high double refraction: when you look closely through the gem, you can see two of each pavilion facet.