Amethyst is an extremely sought-after gem which has been valued by many civilizations since antiquity. A variety of vitreous quartz, amethyst often forms dramatic prismatic crystals which are often formed into jewelry without being cut. Brazil and Uruguay are common sources of high quality amethyst. In the early Christian church, amethyst was believed to guard against intoxication, hence its derivation from the Greek "amethustos," meaning "not drunk."
Citrine is quartz generally occurring in a golden color. Citrine occurs naturally in Scotland and in the Ural Mountains of Russia. Much citrine available today is actually smoky quartz or amethyst that has been heat-treated to achieve its characteristic color.
Spring green peridot is the gem variety of ovaline, a silicate mineral thought to be common in the upper mantle of Earth's crust. Peridot-grade ovaline is most abundant in Pakistan and other dry areas. Used as early as 1580 BC in Egypt, peridot is held as a symbol of the Sun.
Derived from "tapaz," the Sanskrit word for fire, topaz is one of the most brilliant cut gemstones in existence. Topaz comes in a variety of colors from yellow to blue, and deeper blues and pinks are often created by heat-treating stones. Brazil is the world's top exporter of topaz.