Smoky Citrine forms through the combination of Smoky Quartz and Citrine. Smoky Quartz, a variety of Quartz, gets its smoky color from natural radiation and the presence of aluminum impurities during its formation. Natural Citrine, on the other hand, is a variety of Quartz that derives its golden-yellow hue from iron impurities. The blend of these two stones results in the creation of Smoky Citrine.