A variety of quartz ranging in color from yellow to brown. Rarely found naturally, true citrine shows dichroism, in which visible light is split into distinct beams of different wavelengths. Heat treated quartz, commonly amethyst or smokey quartz, has been artificially altered to imitate citrine and does not exhibit dichroism. Most natural citrine is mined in Brazil. The name is derived from the French word “citron” meaning lemon, used to express the common color of the stone.