Citrine (from Latin "citrina"; for yellow) is a variety of the mineral Quartz.
Natural citrines are rare and are mostly pale yellow to golden in colour. Most commercial citrines are heat-treated amethysts or smoky quartzes. Sometimes citrine and amethyst can be found together in the same crystal, which is then referred to as ametrine.
Brazil is the leading producer of citrine, with much of its production coming from the state of Rio Grande do Sul. Other locations include Argentina, Madagascar, Myanmar, Scotland and Spain.
Citrine is one of three traditional birthstones for the month of November. In the Middle Ages people believed that the cosmos was reflected in gemstones. Citrine is assigned to planet Mercury. It was also thought that citrine was to have healing powers for back ache. In ancient times, citrine was carried as a protection against snake venom and evil thoughts. Today it is known as the merchant's stone and is associated with success and prosperity.