Topaz 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.
Topaz is a fairly common and inexpensive gemstone. It can be found in huge and flawless crystals, which can be faceted into giant gemstones which can weigh thousands of carats. Some of the largest gemstone pieces ever cut were of Topaz.
Topaz is a hard and durable gemstone, and will not dissolve in most chemical solvents. However, it does have perfect cleavage which can make it prone to chipping or forming flaws if banged hard. Topaz is also a pleochroic gemstone and can have varied color intensity when viewed at different angles. Due to its good cleavage and pleocroic nature, care must be exercised when faceting Topaz gemstones.