Colors
In its pure form, a topaz is a colorless stone. However, impurities may tint a topaz. There are also brownish and yellowish topaz found in nature, with pink, red, orange and blue ones much more rare.
Hardness
The topaz is an extremely hard mineral and is used on the Moh's scale of hardness, which goes from one to ten, to represent the hardness level associated with eight. This means that it can only be scratched by those minerals with a higher hardness number, such as diamonds.
Breakable
Despite its hardness, topaz tends to break rather easily along its cleavage lines. This makes it better suited for jewelry such as earrings and necklaces that do not get hit or bumped a great deal while being worn.
Geography
Countries such as Pakistan, Sri Lanka, Russia and Brazil are the leading producers of topaz. The mineral was believed by the ancient Greeks to have the ability to make people stronger, and the Egyptians employed the stone to protect themselves from injuries.
Blue topaz
One of the most popular kinds of topaz is the blue topaz. Since these are very hard to come by naturally, gemstone dealers will bombard a clear topaz with radiation and then heat it to attain a blue color. The majority of blue topaz on the market has been treated in this way.