Citrine is a variety of quartz named for its sunny citrusy color. Most commercial citrine on the market is heat treated amethyst (also a type of quartz). Natural citrine is lighter in color than the heat treated stones and is rather rare. Although its name inspires thoughts of tropical sun filled days, take care to avoid prolonged exposure to the sun, as sunlight can discolor your stone. Citrine has a more redish- orange hue than its citrusy cousin, lemon quartz. Citrine is one of November's birthstones.