Although pearl is not an inorganic mineral but rather the organic product of oysters, it is considered by many to be a precious gem, and indeed, the pearl known as La Régente, weighing in at 302.68 grains (or a little over half an ounce), was sold in 1988 for $859,280. Class: sometimes considered precious Origin of Name: perhaps from the Latin perna, a kind of sea mussel Color: creamy white to silver-white; also yellow, pink, green, blue, black Chemical Composition: mostly calcium carbonate, with some conchiolin and water Crystal System: n/a Hardness: n/a Specific Gravity: 2.60-2.78 Geographic Origins: Japan, Australia, Persian Gulf, Venezuela, California, Florida Next Photo: ©Dave G. Houser/Corbis 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