The most expensive color topaz are rich Pink or Red Topaz, followed by rich Orange Topaz. These vivid colors (red, pink, and orange) can cost excess of $1500/ct in contrast with the blue topaz (commonly treated) that is available by not more of $60/ct. Blue Topaz Gem is an affordable gem.
White or Colorless Topaz is ideal for jewelry, its hardness (8 Mohs Scale), transparency, brilliance and its low price, make this white gemstone an affordable choice for your jewels.
The most common color of the topaz is colorless and brown, not blue. The color blue, mostly, is caused by treatment.