Natural blue topazes are rare.
Processing of a blue topaz: almost whole lot of blue topazes in the trade obtain their color after a processing by irradiation (gamma rays), from a natural white topaz.
The legislation is strict, and these topazes, once treated, must be stored before being put into service by laboratories, until there is not rémanente irradiation anymore. There is thus absolutely no risk for the health
There are various handled blue topazes. The clearest are said " topaz sky blue ". They have the color of Aquamarine. Then come topazes with a more intense royal blue color, more "neon"; they are said topazes " Swiss blue ".
Topaz " London blue " has the most intense tint of blue: a blue deep ultramarine with a point of green
According to the Magazine Colored Stone, the Topaz is the most popular second stone after the blue Sapphire.
To know more about the mineralogy of the blue Topaz, see mindat.org ->
