Zircon is one of the most billiant natural gems that comes in colors ranging from golden brown to red to violet to blue. Pure zircon is colorless, but most zircon stones are brown. Zircon stones can be heat-treated to become blue or colorless; sometimes, heat-treated stones revert to their original color. In the middle ages, zircon was said to aid sleep, bring prosperity, and promote honor and wisdom in its owner. The name probably comes from the Persian word zargun which means "gold-colored."