Citrine, the yellow variety of quartz is available in calibrated sizes as well as free sizes in larger individual stones. Citrine is the gem for 13th anniversaries and an alternative birthstone for November. Colours range from pale yellow to rich brandy tones. The hardness is 7 on Mohs scale. Citrine is mined in Brazil, Madagascar and several other African countries. Citrine is doubly refractive with an RI of 1.530 – 1.550 and the specific gravity of Citrine is 2.65 – 2.66.