Topaz's durability makes it sufficient for everyday wear across fine jewelry categories without the protective-setting qualifications softer stones require.
Visually Speaking
London blue topaz sits at the darkest end of the blue topaz spectrum: deeper and cooler than Swiss blue's vivid medium, and significantly more saturated than sky blue's pale brightness. The color differences between grades is the direct result of variations in the irradiation and heat treatment process applied to the same colorless starting material.