The name is derived from its lemon yellow color. Coloring agent is Iron. Natural citrines are Rare. Most commercial citrines are heat- treated Amethyst or smokey quartz. Brazilian Amethyst turns light yellow at 878 degrees F(470 degrees C) and dark yellow to dark brown at 1022-1040 degrees F(550-560 degrees C). Some Smokey quartz turn into citrine color automatically at about 390 degrees F(200 degrees C).
All heat treated citrines have a reddish tint. Natural citrines are pale yellow. There are several names of citrine such as
Bahia, Madeira, Rio Grande etc
CHEMICAL COMPOSITION: SiO2 silicon dioxide SPECIFIC GRAVITY: 2.63 – 2.65 REFRACTIVE INDEX: 1.54 – 1.553 MOHS' HARDNESS: 7 CLEAVAGE: NONE DISPERSION: 0.013 GROWING TEMPERATURE: 350-360 C