Blue Topaz Cut Stone, Octagon, Light, 10 x 12 mm

Blue Topaz is extremely rare to come across so the majority is irradiated, heat treated or both. Doing this, transforms the colourless topaz into a gemstone that is highly sought after. All gemstones that have been exposed to a high level of radiation cannot be made available for sale until the level of radiation has reduced enough to make the stone safe to handle.

Depending on the type of treatment applied, 3 different shades of blue can be produced and each of these have their own name; Sky Blue is the lightest shade and the most known variety of the Blue Topaz and Swiss Blue and London Blue are the shades that come in a deeper and richer blue, both of these are much more expensive then the sky blue shade because of the type of treatment they have been exposed to. 

Shape: Octagon

Size: 10x12mm

Weight: -

Colour: Glassy transparent blue

Moh's hardness:  8

Density: 3.49 - 3.57

Cleavage: Perfect

Refractive index: 1.609 - 1.643

Dispersion: 0.014 (0.008)