Topaz is an excellent, hard-wearing gemstone that comes in many different colours, including white (colourless), green, yellow, blue, pink and brown. With a rating of 8 on the Mohs Scale of Hardness, topaz is sufficiently resistant to scratching that it can be worn regularly when set in jewellery.
Almost all blue topaz on the market has undergone a treatment using both radiation and heat. This variety of topaz is available in a wide range of shades from light to dark blue. The treatment is stable and the stones are very reasonably priced.
Colourless topaz is also relatively abundant, which means that it is often a very affordable gemstone. On the other hand, the so-called Imperial Topaz which has a red-orange colour can fetch quite a high price.
The name topaz is thought to come from the island Topazios in the Red Sea, where gemstones were found in ancient times, but could also have derived from the Greek word "topazos" (meaning "to seek") or the Sanskrit word "tapas" (meaning "fire").
Topaz can occur in large crystals, which means that gem cutters often have the flexibility to transform the rough material into fascinating fancy shapes. One of the biggest faceted examples is the "American Golden" topaz on display at the Smithsonian National Museum of Natural History in Washington, D.C.
It is one of the birthstones for December.
The most significant producer of topaz in the world is Brazil. This gemstone is also found in several other countries, including Sri Lanka, USA, Tasmania, Namibia and Mexico.