Peridot: (Mg,Fe)2SiO4. Peridot, a green colored crystalline variety of the mineral chrysolite or olivine, is a magnesium iron silicate. The gemstone variety of the
mineral olivine is known as Peridot and the shade of green can vary from a yellow-green to brown-green color, however the most valuable is considered to be the dark
olive green. The San Carlos Apache Peridot, found in Southeastern Arizona, is often considered world class gem material. These mines on the Peridot Mesa are among
some of the largest Peridot deposits in the world. This lovely gemstone, which is August's birthstone, was formed during the volcanic Tertiary Period.