Topic summary
Peridot
Peridot ( ), sometimes called chrysolite, is a yellow-green transparent variety of olivine, specifically the magnesium rich end member called forsterite. Peridot is one of the few gemstones that occur in only one color.
Peridot can be found in mafic and ultramafic rocks occurring in lava and peridotitexenoliths of the mantle. The gem occurs in silica-deficient rocks such as volcanic basalt and pallasiticmeteorites. Along with diamonds, peridot is one of only two gems observed to be formed not in Earth's crust, but in the molten rock of the upper mantle. Gem-quality peridot is rare on Earth's surface due to its susceptibility to alteration during its movement from deep within the mantle and weathering at the surface. Peridot has a chemical formula of (Mg,Fe)2SiO4.
Peridot is one of the birthstones for the month of August.