Chemical Formula: (MgFe)2SiO4 Mineral Name: Olivine Color: Varies from yellow to green color Hardness: 6.5 to 7 Peridot, a volcanic gemstone is a yellow-green variety of olivine. It is composed of silica, magnesia and iron. It is the traditional birthstone of August. The gemstone is formed of olivine, a silicate found in igneous rocks and a major constituent of the Earth's upper mantle. The word "peridot" is derived from French word "peritot" meaning unclear. It also believed to take its name from the Arabic word "faridat" meaning gem. Small crystallites of peridot are often found in the basalt rocks created by volcanoes and have been found in iron-nickel meteorites called pallasites. It is found in the USA, Myanmar, Egypt, China, Sri Lanka and Pakistan. Faceted peridot is highly prized gemstone and is also used as birthstone and in making jewelry. It is used both as a faceted and tumbled gem. The faceted stones are used in rings, earrings, pendants, bracelets, and as accent stones. The tumbled gems are embedded in baroque jewelry, drilled and strung as beads, used in mosaics and in producing gem trees.