December is upon us, and of course I have December’s birthstone, blue topaz, at Lava Jewelry.

Topaz occurs in a wide variety of colors, including clear, yellow, orange, brown, red, light to dark blue, pink, violet, and light green. Although topaz does naturally occur in blue, the blue topaz available on the gemstone market is treated. Colorless or light-colored topaz is first irradiated, then heat-treated to give it a blue color. The color of natural blue topaz is not stable, meaning that it fades in sunlight. Topaz that attains its blue color through treatment has a much more stable color.

Blue topaz is often divided into sky blue, Swiss blue, and London blue, with sky blue being the palest shades, and London blue being the darkest.

Topaz has a hardness of 8 on Moh’s hardness scale, but it is prone to cleaving, meaning that its toughness isn’t high. Topaz can be broken by a sharp blow, so it is considered to have a somewhat low durability, even though it is very resistant to scratching.

Topaz is found in pegmatites and placer deposits. (A pegmatite is a granite-type rock with very large crystals.) Quite a bit of the topaz found on the market today is from Brazil, although topaz is found all over the world (Afghanistan, Australia, Burma, China, Japan, Madagascar, Mexico, Namibia, Nigeria, Pakistan, Russia, Zimbabwe, Sir Lanka, U.S.).

Care for topaz is similar to care for most gemstones, but topaz should never been steam-cleaned or cleaned in an ultrasonic cleaner. The best method for cleaning topaz is warm water and a gentle soap. As with all gemstones, it is best not to expose topaz to chemicals (such as household cleaning chemicals) or extreme heat.