Topaz actually has an exceptionally wide color range that,
besides brown, includes various tones and saturations 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. Topaz is often
treated with heat or radiation to make it a deep blue, reddish-orange, pale
green, pink, or purple.