Citrine

Citrine is the yellow to orange variety of Quartz. Natural Citrine is not common; most Citrine on the gem market is produced by heat treating Amethyst and Smoky Quartz. It takes a relatively low temperature to change the color light to golden yellow, and heating to higher temperatures will give the stone a darker yellow to brownish-red color. The name Citrine is derived from the citron fruit, a yellow fruit similar to the lemon. (In fact, citron means "lemon" in several languages.)

Chemical Formula	SiO2
Color	Yellow, Orange, Brown
Hardness	7
Crystal System	Hexagonal
Refractive Index	1.54Â -Â 1.55
SG	2.63Â -Â 2.65
Transparency	Transparent
Double Refraction	.009
Luster	Vitreous
Cleavage	Indiscernible
Mineral Class	Quartz