Blue Topaz
Topaz actually has an exceptionally wide color range that, besides brown, includes various tones and saturation of blue, green, yellow, orange, red, pink, and purple. Colorless topaz is plentiful, and is often treated to give it a blue color. Topaz is also pleochroic, meaning that the gem can show different colors in different crystal directions.
There are a number of processes used to alter the color, apparent clarity, or improve the durability of gems.
Blue Topaz is treated. It comes in Various colors
Baby Sky Blue topaz (BSB)
Sky Blue topaz (SBT)
Swiss Blue Topaz (SWB)
London Blue topaz (LBT)