The hardest substance known, diamond is prized for its exceptional luster and its ability to break up white light into all colors of the rainbow (known as dispersion), which lend the gem its famous fiery brilliance. In 1995, Sotheby's sold a 100.1-carat, pear-shaped "D" flawless diamond to a Saudi Arabian sheikh for $16,548,750, the highest price ever paid for a diamond. (One carat equals one-fifth of a gram.) Class: precious Origin of Name: from the Greek adamas (unconquerable), a nod to its unequaled hardness Color: clear, yellow, brown, green, blue, pink, and rarely, red Chemical Composition: carbon Crystal System: cubic Hardness: 10 Specific Gravity: 3.515 Geographic Origins: South Africa, India, Indonesia, China, Russia, Australia, Brazil, California, Colorado, Canada Next Photo: ©BBC 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