Egyptians and their predecessors mined turquoise in Syria as far back as 4000 B.C., and ancient civilizations of Mexico also prized it for its superb color. Class: semiprecious Origin of Name: probably from the French pierre turquoise (Turkish stone) Color: sky blue Chemical Composition: hydrous phosphate of copper and aluminum Crystal System: triclinic (cryptocrystalline) Hardness: 5-6 Specific Gravity: 2.6-2.9 Geographic Origins: Iran, southwestern U.S. Next Photo: ©International Colored Gemstone Association/Bart Curren 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