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.

Rose quartz can range from very pale pink to an almost cotton candy color and from nearly transparent to a milky opaque. Believed by some to represent love and healing, rose quartz is almost always found in large masses but rarely in crystals. Brazil, Sweden, Scotland and California all have significant deposits of rose quartz.