So precious was peridot to ancient Egyptians that they enslaved residents of St. John's Island (present-day Zebirget) in the Red Sea, forcing them to mine this rich "oily" green mineral for use in jewelry. Class: semiprecious Origin of Name: a French word possibly derived from the Arabic faridat (gem) Color: pale yellowish green to brownish green Chemical Composition: magnesium iron silicate Crystal System: orthorhombic Hardness: 6.5-7 Specific Gravity: 3.22-3.40 Geographic Origins: Zebirget Island (Red Sea), Burma, Pakistan, Norway, Brazil, Arizona, New Mexico Next Photo: ©International Colored Gemstone Association The Science Behind the Sparkle | Diamonds in the Sky A Primer of Gemstones | See Inside a Diamond Resources | Transcript | Site Map | Diamond Deception Home Editor's Picks | Previous Sites | Join Us/E-mail | TV/Web Schedule About NOVA | Teachers | Site Map | Shop | Jobs | Search | To print PBS Online | NOVA Online | WGBH © | Updated November 2000