Topaz can come in a variety of colours including white, yellow, amber, pink, blue, green, gray as well as a colourless stone. The colourless version is most commonly found naturally and it is rare to find natural pink and blue pieces of the stone. Most of the blue topaz sold is actually treated colourless topaz. Pink and red topaz are the most expensive colours as they are rare to find naturally. Gold-Yellow topaz, known as Imperial Topaz, is expensive as it is quite rare to be found naturally.
Topaz can be broken if knocked constantly if it is set in something like a ring. This makes it a good stone for setting in pendants and earrings that wouldn’t get many knocks like a ring.
You can also get man made topaz which should be marked that is has been created so you know what you are buying. Coloured and treated topaz should also be marked when being bought.
On the Mohs scale Topaz has a hardness level of 8.