: A broad category for all other stones, including Amethyst , Topaz , and Opal . Organic Gems : Non-minerals like Amber , Pearl , and Jet . The "4 Cs" of Gemstone Value
: Designed to maximize the stone’s brilliance and showcase its unique color. Carat : The measurement of the stone's weight. Popular Gemstones & Meanings GEMSTONES
Gemstone Buying Guide - The National Association of Jewellers : A broad category for all other stones,