The gemstone Peridot is one of only two gems, the other being Diamond, that is not formed in the Earth’s crust. Rather, it is born in the molten rock of the upper mantle, then brought to the surface by volcanoes and earthquakes. There is another form of Peridot that is not even native to the planet. It is found in rare pallasite meteorites believed to have been formed 4.5 billion years ago. Peridot is one of few stones that occurs naturally in only one color, which may range from yellow-green to olive green to brownish green, due to variations in iron content.