Blue topaz is usually categorized on to one of the following: London blue, Swiss blue or Sky blue with London Blue being the darkest.
Topaz are usually colorless but natural imperfections give it color. The gem can be heat treated enhance colors. That is the way most blue topaz achieve their color. Naturally occurring blue topaz are very rare.
Topaz has been used medicinally for centuries for protection against disease and to increase strength. Historically they were given to Royalty to bring good health, strengthen the mind and expand wisdom. One of the worlds most famous topazes is set in the Portuguese Crown Jewels and is referred to as the "Braganza Diamond" as it was mistaken for a diamond weighing an estimated 1,680 carats.
All of our December birthstone Claddagh rings are set with lab created heart shaped blue topaz.