Peridot << PEHR uh dot >> is a transparent gem that is almost always some shade of green because of its iron content. Peridots are a variety of a common rock-forming mineral called olivine. Jewelers cut and polish the highest-quality peridot stones so that each gem has many flat surfaces called facets. Faceted peridots are used in all types of fine jewelry. Jewelers cut lesser-quality peridots into a rounded style called cabochon, or polish them with abrasives in a process called tumbling. These lesser-quality peridots are used in costume jewelry and decorative objects. Peridot is one of the two birthstones for August.
Peridots have been known since Biblical times. The earliest source of peridots was Jazirat Zabarjad (St. John’s Island), off the Egyptian coast in the Red Sea. In the United States, Arizona and New Mexico are important commercial sources of peridots.
