Peridot is the official birthstone of August. Peridot is a gemstone-quality of the mineral Olivine. It is a stone of natural phenomenon because it forms under tremendous heat and pressure. As a result, it is a rare gemstone. In addition, Peridot has been found in rocks created by volcanoes. In fact, these gemstones have even been found in meteors that fall to Earth! Peridot colour ranges from yellow-green to olive green to brown-green. This gemstone is one of the few gemstones that are found in a single colour.