The November birthstone is found naturally in many colors: yellows, pinks, oranges, browns and even colorless. Reportedly, natural blue gems have also been mined in Russia, but the typical blue topaz found in the marketplace has been irradiated in a lab to obtain its blue coloring.
Topaz is a relatively hard stone, but it has a cleavage plane which can sheer if the gem is hit hard. Properly cut stones position this cleavage plane on an angle to minimize this possibility. Topaz crystals are found in large sizes, and per carat price does not carry a significant premium as gem size increases.
Natural crystals tend to be somewhat long in relationship to width, and polished gems are often cut in this same long-narrow fashion; well proportioned gems carry a premium price. Citrine, a yellow quartz, is sometimes incorrectly called "golden Topaz", but this name is misleading and should be avoided. Major topaz mines are in Brazil, Mexico and Sri Lanka.
