Peridot is a beautiful and unique gemstone that has been used for centuries for its physical and spiritual properties. This August birthstone is one of the few gemstones that occur in only one color, olive green. It is also called the evening emerald because of the slight variations between brownish and olive green. Peridot is formed from magnesium and iron silicate and is most commonly found in volcanic rocks and meteorites. The name peridot is derived from the Arabic word "faridat," which means "gem."