Citrine’s name derives from its lemon yellow color, and from the old French word citrine, meaning “lemon.” It is a yellow to brownish quartz (silicon dioxide) and resembles yellow topaz. Citrine has been popular for thousands of years and revered for its rarity. Citrine occurs in igneous and metamorphic rocks, particularly in granite and gneiss. It is also found in clastic sediments. Because it resists weather, citrine is also found in alluvial sands and gravels.
The coloring agent of citrine, is iron. The most valuable stones are the darkest, sometimes known as “Madeira citrine” for its resemblance to the color of fortified wine. Natural citrine is less common than amethyst or smoky quartz, both of which can be heat-treated to turn their color into that of citrine. Most citrine that is available in the market today is heat treated amethyst.
Citrine is found in localities that produce amethyst, and it is sometimes found as a zone of citrine in amethyst, when it is known as ametrine. Natural, bright yellow citrine is the rarest of the quartz varieties. Well-colored citrines are used as ring stones and pendants; less attractive stones are used in making necklaces or ornaments.