makes an ideal gem. A good hardness and desirable colors, combined with a
relative abundance and availability makes it one the most popular gemstones.
The most valuable colors of Topaz are the golden orange-yellow type,
called Imperial Topaz, and the dark pinkish-red and
orange-red colors. Value increases with a deepness of color in orange and
reddish hues. The most commonly used colors of Topaz in jewelry are the blue
types. It was not until this past century that blue Topaz became widespread on
the gem market, since virtually all blue gem Topaz is irradiated and heat treated.