Citrine is the yellow to orange assortment of Quartz. Normal Citrine isn't normal; most Citrine on the pearl market is delivered by heat treating Amethyst and Smoky Quartz. It takes a generally low temperature to change the shading light to brilliant yellow, and warming to higher temperatures will give the stone a hazier yellow to earthy red tone. The name Citrine is gotten from the citron natural product, a yellow natural product like the lemon. (Indeed, citron signifies "lemon" in a few dialects.)
CITRIN Color Stone