01Nov Facts about Citrine
Citrine is the yellow variety of macrocrystalline quartz and comes in a range of yellow to orange colours. It can be very pale through to vivid. The colour comes from a trace element of iron in the crystal. Its chemical composition is silicon dioxide (silica) and it forms in the trigonal crystal system. It is often round in quite large crystals.
It is found in many locations, including Sri Lanka, Tanzania, Brazil, Madagascar, Canada, Myanmar and Bolivia.
Natural citrine is relatively rare and the majority of citrine on the market is heat-treated amethyst or smoky quartz. When made using this process, the colour comes from finely distributed iron minerals (mostly hematite and goethite). Hence, heated amethyst is not citrine in the strictest sense, even though it is still yellow quartz.
Citrine has a hardness of 7 on the Mohs Scale (out of 10), a refractive index of 1.544 to 1.553 and a specific gravity of 2.65. It has a vitreous lustre and is usually transparent or translucent.
Citrine is one of the birthstones for November. It is an affordable gemstone, with even large stones of 10-20 carats offered at reasonable prices.
When citrine and amethyst form in the same crystal, the stone is called ametrine.
For more information on citrine, check out this page - http://www.quartzpage.de/citrine.html